HYBRID MOBILE ELEMENT, METHOD AND DEVICE FOR INTERFACING A PLURALITY OF HYBRID MOBILE ELEMENTS WITH

专利摘要:
The subject of the invention is in particular a hybrid mobile element for a device for interfacing a plurality of mobile elements with a computer system, said hybrid mobile element comprising at least one location module comprising the following means: means for transmitting an electromagnetic signal enabling determining the position of said location module; and, means for receiving an activation signal and, according to at least one information of said activation signal, activating said means for transmitting an electromagnetic signal; said hybrid mobile element being characterized in that it further comprises: an inertial unit integral with said location module; and - means of communication with said device, for transmitting data relating to a displacement of the inertial unit.
公开号:FR3046261A1
申请号:FR1563352
申请日:2015-12-24
公开日:2017-06-30
发明作者:Valentin Lefevre；Laurent Chabin；Christophe Duteil
申请人:EPAWN；
IPC主号:

专利说明:

où E désigne la tension aux bornes du solénoïde 300, R désigne la tension du signal reçu aux bornes 301 de la boucle de réception 211, D est la distance entre le solénoïde 300 et la boucle de réception 211 et k est une constante liée à des facteurs intrinsèques du système comprenant le solénoïde et la boucle de réception, notamment le nombre de spires du solénoïde et la taille de la boucle.
La figure 3b illustre schématiquement un mécanisme d’interpolation permettant de déterminer la position d’un solénoïde placé sur une surface de détection, selon un axe donné, à partir de mesures obtenues par un système tel que celui décrit en référence à la figure 2. Ce mécanisme peut être mis en œuvre dans l’étape 403 (figure 4) de calcul de la position de l’élément mobile hybride à partir du signal (champ électromagnétique) reçu de son module de localisation.
Il est supposé ici que le solénoïde se situe à proximité de boucles verticales B3, B4 et B5, positionnées selon des abscisses X3, X4 et X5, les tensions mesurées aux bornes de ces boucles étant notées V3, V4 et V5, respectivement. Le solénoïde se trouve ici a une position, en abscisse, notée XS.
Les coordonnées X3, X4 et X5 peuvent être obtenues par l’unité centrale de traitement de l’élément de sol (ou dispositif d’interfaçage) à partir d’un identifiant de la boucle correspondante (ces valeurs sont prédéfinies selon le schéma de routage de la surface de détection et, de préférence, mémorisées dans une mémoire non volatile).
La portion de courbe 302 représentée sur la figure 3b illustre la variation de tension pour la position XS du solénoïde selon les positions des boucles couplées avec le solénoïde, extrapolée à partir des valeurs mesurées par les boucles B3, B4 et B5. Elle peut être assimilée à une fonction du second degré de type parabolique. Cette approximation locale correspond, en pratique, au phénomène de couplage électromagnétique entre un solénoïde et des boucles d’une grille conductrice.
Les relations suivantes illustrent cette propriété :
où a et b sont des constantes, a étant une constante inférieure à zéro (a<0).
Par ailleurs, compte tenu de l’hypothèse d’une fonction du second degré, les relations entre les abscisses X3, X4 et X5 peuvent s’exprimer sous la forme suivante :
ΔΧ représentant la distance entre les abscisses X3 et X4 et entre les abscisses X4 et X5).
Ainsi, il est possible d’interpoler la position du solénoïde selon la formule suivante :
Il est également possible, selon la même logique, de déterminer la position du solénoïde selon l’axe des ordonnées.
En outre, la distance entre le solénoïde et la boucle (c’est à dire l’altitude du solénoïde par rapport à la surface de détection) peut être définie selon la relation suivante :
La distance D est donc fonction de la valeur R représentant la tension aux bornes des boucles considérées de la surface de détection. Elle peut être extrapolée à partir des mesures réalisées. Il est noté que la précision de ce calcul de distance est notamment liée à la stabilité du signal E émis par le solénoïde dont la valeur doit être aussi constante que possible au cours du temps, ce qui nécessite une alimentation stabilisée dans le module de localisation qui ne doit pas chuter lors de la décharge de la batterie. Ceci peut être assuré par un régulateur de tension du module de localisation.
Les figures 4a et 4b sont des organigrammes représentant des étapes mises en oeuvre respectivement par un dispositif d’interfaçage (figure 4a) et un élément mobile hybride (figure 4b) selon un premier mode de réalisation de l’invention.
Les figures 4a et 4b illustrent un premier exemple d’algorithme pouvant être utilisé pour calculer les positions et/ou orientations d’éléments mobiles hybrides.
Dans ce premier exemple, le calcul hybride de la position en cas de défaut de réception d’un signal électromagnétique en provenance du module de localisation sélectionné (c’est-à-dire en l’absence de réception d’un signal électromagnétique lors de l’activation du module de localisation) est mis en œuvre dans le dispositif d’interfaçage, par exemple par une unité centrale de traitement de l’élément de sol 101 représenté sur la figure 1.
On décrit ici les étapes mises en œuvre par le dispositif d’interfaçage selon ce premier mode de réalisation en référence à la figure 4a.
Au cours d’une première étape 401, un module de localisation intégré à un élément mobile hybride est sélectionné et activé par le dispositif d’interfaçage.
En pratique, le dispositif d’interfaçage sélectionne un identifiant de module de localisation parmi une pluralité d’identifiants. A titre d’illustration, l’unité centrale de traitement 230 du dispositif d’interfaçage transmet à l’émetteur radio 227 du dispositif d’interfaçage un identifiant d’un module de localisation à activer. Cet identifiant est codé afin d’être transmis à l’ensemble des modules de localisation sous forme de signal numérique ou analogique d’activation. Chaque module de localisation recevant ce signal peut alors comparer l’identifiant reçu avec son propre identifiant et s’activer si les identifiants sont identiques. Cette activation consiste par exemple à alimenter le solénoïde 300 du module de localisation sélectionné pour qu’il émette un champ électromagnétique.
Au cours d’une étape 402, un test est réalisé pour savoir si un signal en provenance du module sélectionné est reçu.
En pratique, lorsqu’un module de localisation est sélectionné et activé comme décrit précédemment, il émet un signal, par exemple un champ électromagnétique, à l’attention du dispositif d’interfaçage, en particulier de sa surface de détection 210.
Toutefois, lorsque le module de localisation émet ce champ électromagnétique alors qu’il est hors de la portée de détection de la surface de détection 210 du dispositif d’interfaçage, celui-ci ne peut pas détecter le champ électromagnétique émis et ne peut donc pas calculer la position à partir de celui-ci. L’étape 402 consiste à détecter une telle situation.
Lorsque le champ électromagnétique émis par le module de localisation activé est détecté au cours de l’étape 402, cela signifie que celui-ci est dans la portée de détection de la surface de détection 210 du dispositif d’interfaçage.
Une information de position peut alors être calculée à l’étape 403, à partir du champ électromagnétique reçu, par exemple par interpolation comme décrit en référence à la figure 3b.
Cette information de position est ensuite mémorisée en association avec la date de son calcul dans une mémoire du dispositif d’interfaçage (étape 404). Comme il sera expliqué plus en détails par la suite, cette information de position ainsi que la date associée seront utilisées pour recaler des données de déplacement issues de la centrale inertielle de l’élément mobile hybride sélectionné, préalablement ou au cours du calcul hybride d’une nouvelle information de position à un moment où le calcul de l’information de position selon l’étape 403 n’est pas possible.
Lorsqu’aucun champ électromagnétique n’est détecté par la surface de détection 210 du dispositif d’interfaçage au cours de l’étape 402, cela signifie que le module de localisation sélectionné est hors de portée de la surface de détection 210.
Dans ce cas, des données de déplacement d’une centrale inertielle solidaire du module de localisation sélectionné sont obtenues (étape 405). En pratique, ces données de déplacement sont datées et sont reçues via les moyens de communication 228 (éventuellement confondus avec l’émetteur-récepteur HF 227) du dispositif d’interfaçage. Par exemple, ces données de déplacement sont obtenues sur requête du dispositif d’interfaçage. En variante, l’élément mobile hybride peut transmettre régulièrement des données de déplacement dispositif d’interfaçage, par exemple toutes les secondes ou 100 fois par seconde, selon l’application visée (par exemple réalité augmentée ou virtuelle).
Comme mentionné précédemment, les données de déplacement du module de localisation mesurées par la centrale inertielle solidaire de ce module de localisation comprennent par exemple : - une (ou plusieurs) vitesse(s) de rotation à un instant donné fournie par un gyromètre ; - une (ou plusieurs) accélération(s) à un instant donné fournie par un accéléromètre ; - une (ou plusieurs) estimation(s) de la direction du champ magnétique à un instant donné fournie par un magnétomètre.
Cette liste n’est pas limitative. Ces données de déplacement peuvent être obtenues par différents capteurs.
Au cours d’une étape 406 optionnelle, les données de déplacement obtenues à l’étape 405 sont traitées de sorte à corriger une éventuelle dérive temporelle ou l’effet d’un choc subis par la centrale inertielle. Ce traitement, appelé « recalage », est basé sur une ou plusieurs positions calculées au cours de l’étape 403 à partir d’un signal électromagnétique émis à un instant précédent par le module de localisation sélectionné alors qu’il était dans la portée de la surface de détection 210. Comme mentionné précédemment, une telle position est mémorisée avec sa date de calcul (étape 404). La connaissance de la date du calcul et de la valeur de la position à ce moment précis permet de recaler les données de la centrale inertielle, elles-mêmes datées. A titre d’illustration, le dispositif d’interfaçage peut suivre, à partir de calcul successifs de la position d’un même module de localisation, l’évolution au cours du temps de sa position et ainsi identifier les moments où ce module de localisation a une vitesse nulle caractérisant un contact sans glissement. Ces moments particuliers (de contact sans glissement) permettent de recaler les positions calculées à partir des données de déplacement de la centrale inertielle, par exemple en réinitialisant la vitesse estimée à zéro.
On remarquera qu’un élément mobile hybride comprenant deux modules de localisation permet d’ores et déjà de corriger la dérive des données de déplacement de la centrale inertielle autour de l’axe vertical de l’élément mobile hybride.
Au cours d’une étape 407, le dispositif d’interfaçage effectue un calcul hybride d’une nouvelle information de position du module de localisation sélectionné. Ce calcul particulier est qualifié d’hybride car il utilise d’une part les données de déplacement de la centrale inertielle obtenues à l’étape 405, éventuellement recalées (si besoin) à l’étape 406, et d’autre part une ou plusieurs information(s) de position précédemment calculée(s) alors que le module de localisation sélectionné était dans la portée de détection (i.e. selon une étape 403). L’homme du métier comprend que ce calcul hybride (étape 407) prend en compte la date des données de déplacement et celle de l’information de position antérieure, préalablement mémorisée à l’étape 404.
En effet, afin de permettre le calcul hybride cohérent, les données de déplacement reçues de l’élément mobile hybride et les informations de position calculées par le dispositif d’interfaçage sont synchronisées.
Pour ce faire, le dispositif d’interfaçage peut envoyer un top à rythme régulier, en indiquant à quel instant (dans son horloge locale) correspond ce top. Ainsi l’élément mobile hybride est capable de déterminer la date des données qu’il envoie, notamment des données de déplacement de la centrale inertielle, exprimée dans l’horloge locale du dispositif d’interfaçage.
En variante, il est possible d’utiliser un compteur de tops au niveau du dispositif d’interfaçage et d’affecter un numéro de top aux données de déplacement reçues.
Selon une autre possibilité, un protocole de synchronisation d’horloges peut être utilisé, par exemple le protocole NTP (acronyme pour Network Time Protocol en terminologie anglo-saxonne) pour synchroniser les horloges de l’élément mobile hybride et du dispositif d’interfaçage.
Ainsi, le calcul hybride 407 permet, en l’absence d’un champ électromagnétique émis par le solénoïde du module de localisation sélectionné, de déterminer une information de position instantanée, à partir d’une ancienne information de position et de données de déplacement. A titre d’illustration, supposons que les données de déplacement comprennent la vitesse V(T1) de déplacement du module de localisation. Alors, le calcul hybride de la position P(T1) du module de déplacement au temps T1 peut être effectué par application de la formule suivante : 7(71) = 7(70) + V(71).(71 - 70) Où P(T1) est la position du module de localisation calculée au temps T1, P(T0) est la position du module de localisation calculée au temps T0 (antérieur à T1 ), V(T 1 ) est la vitesse du module de localisation au temps T1.
Cet exemple n’est pas limitatif et des calculs plus complexes, par exemple comprenant une ou plusieurs intégrations dans le temps peuvent être mis en œuvre.
Notamment, un tel calcul hybride comprenant éventuellement le recalage susmentionné, peut par exemple se baser sur des algorithmes d’hybridation bien connus de l’homme du métier tel que les filtres de Kalman, de Kalman étendu ou des filtres complémentaires.
Ainsi, l’invention permet d’obtenir en temps réel une information de position d’un module de localisation activé (étape 403 ou étape 407), que l’élément mobile hybride soit ou non dans la portée de détection de la surface de détection, ceci à partir de deux types de données : les données de déplacement de la centrale inertielle solidaire du module de localisation, et les signaux électromagnétiques émis par celui-ci lorsque qu’il est dans la portée de détection de la surface de détection.
Avantageusement, la combinaison de la centrale inertielle avec le module de localisation, constituant des systèmes différents aux caractéristiques complémentaires, permet de pallier les insuffisances de chacun d’eux. Par exemple, le calcul de la position du module de localisation à partir de signaux électromagnétiques qu’il émet (étape 403), est précis et ne souffre pas de problème de dérive dans le temps, mais ce calcul est subordonné à la portée de détection limitée de la surface de détection 210.
La centrale inertielle quant à elle constitue un autre moyen de positionnement basé sur des principes physiques différents, à savoir l’inertie, dont les mesures sont autonomes et fiables. Les problèmes de dérive dans le temps ou l’effet de chocs subis par la centrale inertielle peuvent être solutionnés par l’utilisation d’anciennes positions calculées au cours d’étapes 403.
De manière correspondante, et comme représenté sur la figure 4b, l’élément mobile hybride reçoit un signal d’activation (étape 408) envoyé par le dispositif d’interfaçage à l’étape 401. A titre d’illustration, le récepteur radio 602 de l’élément mobile hybride représenté sur la figure 6 reçoit une commande d’activation comprenant un identifiant de module de localisation sous forme codée. L’élément mobile hybride recevant ce signal peut alors comparer l’identifiant reçu avec l’identifiant de son ou ses modules de localisation et activer celui-ci si les identifiants sont identiques. Cette activation consiste par exemple à alimenter le solénoïde 300 du module de localisation sélectionné pour qu’il émette un champ électromagnétique.
Au cours d’une étape 409, le module de localisation ainsi activé émet un signal, par exemple un champ électromagnétique. Toutefois, même si un tel signal est émis, il n’est pas nécessairement reçu par le dispositif d’interfaçage. Notamment, si le module de localisation est hors de portée de la surface de détection 210, alors le signal électromagnétique est émis mais n’est pas perçu par la surface de détection 210.
Au cours d’une étape 410, l’élément mobile hybride transmet des données de déplacement de la centrale inertielle, lesquelles sont reçues par le dispositif d’interfaçage au cours de l’étape 405.
En pratique, comme représenté sur la figure 6, ces données de déplacement sont générées par les capteurs de la centrale inertielle 607 et sont récupérées (et datées) par l’unité de traitement 609 de l’élément mobile hybride afin d’être envoyées via les moyens de communication 608 (éventuellement confondus avec l’émetteur-récepteur 602). La date potentiellement affectée aux données de déplacement a pour but de permettre la synchronisation de ces dernières avec les positions mémorisées dans le dispositif d’interfaçage à l’étape 404. Comme mentionné précédemment, cette synchronisation est permise soit par une datation des données de déplacement au niveau de l’élément hybride, dans l’horloge du dispositif d’interfaçage avant envoi (envoi de tops à rythme régulier et de dates correspondantes dans le référentiel de l’horloge du dispositif d’interfaçage, utilisation de protocole de synchronisation d’horloges par exemple NTP), soit au niveau du dispositif d’interfaçage (compteur de tops).
Cette étape 410 peut être effectuée sur requête du dispositif d’interfaçage ou bien régulièrement, par exemple toutes les secondes ou 100 fois par seconde, selon l’application visée (par exemple réalité augmentée ou virtuelle).
Les figures 4c et 4d sont des organigrammes représentant des étapes mises en oeuvre respectivement par un dispositif d’interfaçage (figure 4c) et un élément mobile hybride (figure 4d) selon un second mode de réalisation de l’invention.
Les figures 4c et 4d illustrent un second exemple d’algorithme pouvant être utilisé pour calculer les positions et/ou orientations d’éléments mobiles hybrides.
Dans ce second exemple, le calcul hybride de la position en cas de défaut de réception d’un signal électromagnétique en provenance du module de localisation sélectionné (c’est-à-dire en l’absence de réception d’un signal électromagnétique lors de l’activation du module de localisation) est mis en œuvre dans l’élément mobile hybride sélectionné et activé par dispositif d’interfaçage, par exemple par l’unité de traitement 609 représentée sur la figure 6 et chargée du traitement des données issues de la centrale inertielle ou du module de localisation associé.
On décrit ici les étapes mises en œuvre par le dispositif d’interfaçage selon ce second mode de réalisation en référence à la figure 4c.
Au cours d’une première étape 411, similaire à l’étape 401 de la figure 4a, un module de localisation intégré à un élément mobile hybride est sélectionné et activé par le dispositif d’interfaçage.
Au cours d’une étape 412, similaire à l’étape 402 de la figure 4a, un test est réalisé pour savoir si un signal en provenance du module sélectionné est reçu.
En pratique, lorsqu’un module de localisation est sélectionné et activé comme décrit précédemment, il émet un signal, par exemple un champ électromagnétique, à l’attention du dispositif d’interfaçage, en particulier de sa surface de détection 210.
Toutefois, lorsque le module de localisation émet ce champ électromagnétique alors qu’il est hors de la portée de détection de la surface de détection 210 du dispositif d’interfaçage, celui-ci ne peut pas détecter le champ électromagnétique émis et ne peut donc pas calculer la position à partir de celui-ci. L’étape 412 consiste à détecter une telle situation.
Lorsque le champ électromagnétique émis par le module de localisation activé est détecté au cours de l’étape 412, cela signifie que celui-ci est dans la portée de détection de la surface de détection 210 du dispositif d’interfaçage.
Une information de position peut alors être calculée à l’étape 413, similaire à l’étape 403 de la figure 4a, à partir du champ électromagnétique reçu, par exemple par interpolation comme décrit en référence à la figure 3b.
Cette information de position est ensuite mémorisée en association avec la date de son calcul dans une mémoire du dispositif d’interfaçage (étape 414 similaire à l’étape 404 de la figure 4a).
Comme il sera expliqué plus en détails par la suite, cette information de position ainsi que la date associée seront utilisées par l’élément mobile hybride pour recaler des données de déplacement issues de la centrale inertielle, préalablement ou au cours du calcul hybride d’une nouvelle information de position à un moment où le calcul de l’information de position par le dispositif d’interfaçage selon l’étape 413 n’est pas possible.
Pour ce faire, le dispositif d’interfaçage transmet des données de recalage basées sur la position calculée à l’étape 413 et mémorisée avec sa date à l’étape 414. Selon un mode de réalisation particulier, ces données de recalage comprennent directement cette position ainsi que sa date. Selon un autre mode de réalisation particulier, les données de recalage peuvent par exemple comprendre une instruction de réinitialisation des capteurs de la centrale inertielle, de sorte que les prochaines données de déplacement mesurées par celle-ci seront représentatives d’un déplacement du module de localisation par rapport à sa position telle que calculée à l’étape 413. Les données de recalage peuvent comprendre en variante d’autres informations basées sur une ou plusieurs positions calculées par le dispositif d’interfaçage, par exemple une vitesse ou une accélération à un moment donné.
Lorsqu’aucun champ électromagnétique n’est détecté par la surface de détection 210 du dispositif d’interfaçage au cours de l’étape 412, cela signifie que le module de localisation sélectionné est hors de portée de la surface de détection 210.
Dans ce cas, le dispositif d’interfaçage en informe l’élément mobile hybride comprenant le module de localisation correspondant, au cours d’une étape 416. En pratique, cette information est envoyée via les moyens de communication 228 (éventuellement confondus avec l’émetteur-récepteur HF 227) commandés par l’unité de traitement 230 du dispositif d’interfaçage.
Cette information peut être directement la dernière position calculée par le dispositif d’interfaçage à partir d’un signal électromagnétique. A noter que dans certains modes de réalisation dans lesquels les données de recalage envoyées à l’étape 415 comprennent directement la position ou permettent de déduire cette position, l’élément mobile hybride est d’ores-et-déjà en possession de cette information de position. Ainsi, l’information envoyée à l’étape 416 peut consister simplement en une instruction de déclenchement du calcul hybride.
Au cours d’une étape 417, le dispositif d’interfaçage reçoit la position de l’élément mobile hybride, laquelle, dans ce mode de réalisation, est calculée par l’élément mobile hybride, comme cela sera décrit plus en détail en référence à la figure 4d qui représente les étapes mises en œuvre au niveau de l’élément mobile hybride dans ce second mode de réalisation.
Ainsi, l’invention permet d’obtenir en temps réel une information de position d’un module de localisation activé (étape 413 ou étape 417), que l’élément mobile hybride soit ou non dans la portée de détection de la surface de détection, ceci à partir de deux types de données : les données de déplacement de la centrale inertielle solidaire du module de localisation, et les signaux électromagnétiques émis par celui-ci lorsque qu’il est dans la portée de détection de la surface de détection.
De manière correspondante, et comme représenté sur la figure 4d, l’élément mobile hybride reçoit un signal d’activation (étape 418 similaire à l’étape 408 de la figure 4b) envoyé par le dispositif d’interfaçage à l’étape 411.
Au cours d’une étape 419, similaire à l’étape 409 de la figure 4b, le module de localisation ainsi activé émet un signal, par exemple un champ électromagnétique. Il est rappelé que même si un tel signal est émis, il n’est pas nécessairement reçu par le dispositif d’interfaçage. Notamment, si le module de localisation est hors de portée de la surface de détection 210, alors le signal électromagnétique est émis mais n’est pas perçu par la surface de détection 210.
Au cours d’une étape 420, un test est réalisé pour savoir si une information en provenance du dispositif d’interfaçage est reçue, indiquant que celui-ci n’a pas reçu le signal électromagnétique attendu. Comme expliqué précédemment, cette situation se présente lorsque le module de localisation émettant ce signal à l’étape 419 est situé hors de portée de la surface de détection 210.
Lorsqu’aucune information de ce type n’est reçue après un certain temps prédéterminé, par exemple égal à la durée entre deux tops d’horloge de l’élément mobile hybride, cela signifie que le signal électromagnétique émis par le module de localisation à l’étape 419 a bien été reçu (celui-ci est alors situé dans la portée de la surface de détection 210) par le dispositif d’interfaçage et qu’une information de position peut être calculée par celui-ci à partir de ce signal (étape 413 de la figure 4c).
Au cours d’une étape 421, l’élément mobile hybride reçoit des données de recalage envoyées par le dispositif d’interfaçage (étape 415 de la figure 4c). Pour rappel, ces données de recalage sont calculées par le dispositif d’interfaçage à partir de la position calculée grâce au signal électromagnétique reçu en provenance du module de localisation activé.
Lorsqu’au contraire l’élément mobile hybride reçoit une information indiquant qu’aucun signal n’a été reçu de la part du module de localisation activé, cela signifie que le signal électromagnétique émis par le module de localisation à l’étape 419 n’a pas atteint la surface de détection 210 et que le module de localisation est situé hors de portée de la surface de détection 210.
Dans ce cas, l’élément mobile hybride récupère les données de déplacement de la centrale inertielle ainsi que leur date (étape 422), par exemple dans une mémoire associée à celle-ci. En pratique, comme représenté sur la figure 6, c’est l’unité de traitement 609 qui obtient les données de déplacement de la centrale inertielle 607.
Au cours d’une étape 423, similaire à l’étape 406 de la figure 4a à ceci près qu’elle est basée sur les données de recalage reçues en 421, les données de déplacement obtenues à l’étape 422 sont traitées par l’élément mobile hybride de sorte à corriger une éventuelle dérive temporelle ou l’effet d’un choc subis par la centrale inertielle.
Ce traitement de recalage est basé sur une ou plusieurs positions calculées par le dispositif d’interfaçage à partir d’un signal électromagnétique émis à un instant précédent par le module de localisation sélectionné alors qu’il était dans la portée de la surface de détection 210. Comme mentionné précédemment, une telle position est typiquement reçue sous forme de données de recalage avec la date associée. Selon une variante de réalisation, une position calculée par le dispositif d’interfaçage peut être reçue en tant qu’information en 420. La connaissance de la date du calcul de la position reçue et de la valeur de la position à ce moment précis permet de recaler les données de la centrale inertielle, elles-mêmes datées, comme expliqué en référence à l’étape 406 de la figure 4a.
Au cours d’une étape 424, similaire à l’étape 407 de la figure 4a, l’élément mobile hybride effectue un calcul hybride d’une nouvelle information de position du module de localisation sélectionné. Il est rappelé que ce calcul particulier est qualifié d’hybride car il utilise d’une part les données de déplacement de la centrale inertielle recalées à l’étape 423, et d’autre part une ou plusieurs information(s) de position précédemment calculée(s) (par exemple reçues comme données de recalage à l’étape 421) par le dispositif d’interfaçage alors que le module de localisation sélectionné était dans la portée de détection (i.e. selon une étape 413 de la figure 4c). Des détails sur le calcul hybride ont été donnés précédemment en référence à l’étape 407 de la figure 4a (premier mode de réalisation), ils ne seront pas répétés ici.
Il est rappelé toutefois qu’un tel calcul hybride (ainsi que le recalage) peut par exemple se baser sur des algorithmes d’hybridation bien connus de l’homme du métier tel que les filtres de Kalman, de Kalman étendu ou des filtres complémentaires.
Ainsi, dans ce second mode de réalisation également, le calcul hybride 424 permet, en l’absence d’un champ électromagnétique émis par le module de localisation sélectionné, de déterminer une information de position instantanée, à partir d’une ancienne information de position et de données de déplacement.
Enfin, l’élément mobile hybride transmet la position ainsi calculée au dispositif d’interfaçage au cours d’une étape 425. Ainsi, le dispositif d’interfaçage obtient une information de position bien qu’il n’ait pas pu la calculer lui-même en l’absence de détection du champ électromagnétique émis par module de localisation.
Les figures 5a et 5b illustrent schématiquement deux exemples d’éléments mobiles hybrides dont la position peut être déterminée et dont la position et l’orientation peuvent être déterminées, respectivement, conformément à des modes particuliers de réalisation de l’invention. L’élément mobile hybride 500 représenté sur la figure 5a comprend un seul module de localisation 501. Comme illustré, le module de localisation comprend un solénoïde. L’axe radial du solénoïde est avantageusement perpendiculaire au plan de l’élément de sol afin que le rayonnement électromagnétique du solénoïde se propage de façon optimale vers cette surface.
Cet élément mobile hybride 500 comprend en outre une centrale inertielle 502 solidaire du module de localisation 401, ainsi que des moyens de communication 503 pour envoyer des données relatives au déplacement de la centrale inertielle 502.
La position tridimensionnelle de l’élément mobile hybride 500, comprenant un seul solénoïde, peut être calculée conformément à l’invention, comme décrit précédemment. En effet, à partir des données de déplacement de la centrale inertielle solidaire 502 et/ou à partir du signal émis par le solénoïde du module de localisation 501, il est possible de calculer la position hybride à tout instant. Lorsque plusieurs éléments mobiles sont présents sur la surface de détection 210, la position de chaque élément mobile hybride est déterminée de façon séquentielle. L’élément mobile hybride 500’ représenté sur la figure 5b comprend deux modules indépendants de localisation 501-1 et 501-2. A nouveau, comme illustré, l’axe radial des solénoïdes est avantageusement perpendiculaire au plan de la surface de détection afin que le rayonnement électromagnétique du solénoïde se propage de façon optimale vers cette surface.
Cet élément mobile hybride 500’ comprend en outre une centrale inertielle 502’ solidaire des modules de localisation 501-1 et 501-2, ainsi que des moyens de communication 503’ pour envoyer des données relatives au déplacement de la centrale inertielle 502’.
Chaque solénoïde 501-1 et 501-2 de l’élément mobile hybride 500’ peut être activé indépendamment l’un de l’autre, de façon séquentielle. Ainsi, il est possible de déterminer la position de l’élément mobile hybride 500’ en déterminant la position de chaque solénoïde des modules de localisation 501-1 et 501-2 et en connaissant leur position dans l’élément mobile hybride 500’. De même, il est possible de connaître l’orientation de cet élément mobile hybride à partir des positions relatives des solénoïdes des modules de localisation 501-1 et 501-2 et de leur position dans l’élément mobile hybride 500’. Il convient d’observer ici que l’utilisation des coordonnées des solénoïdes des modules de localisation 501-1 et 501-2, dans le plan de la surface de détection, permet de déterminer l’orientation de l’élément mobile hybride 500’ dans ce plan tandis que l’utilisation de l’altitude des solénoïdes des modules de localisation 501-1 et 501-2 permet de calculer le tangage de l’élément mobile hybride 500’.
La position tridimensionnelle et l’orientation de l’élément mobile hybride 500’, comprenant deux solénoïdes, peuvent être calculées conformément à l’invention, comme décrit précédemment. En effet, à partir des données de déplacement de la centrale inertielle 502’ et/ou à partir des signaux émis séquentiellement par les solénoïdes des modules de localisation 501-1 et 501-2, il est possible de calculer la position hybride à tout instant. Lorsque plusieurs éléments mobiles sont présents sur la surface de détection 210, la position de chaque élément mobile hybride est déterminée de façon séquentielle.
Il est noté ici que des éléments mobiles hybrides comprenant un seul solénoïde et comprenant deux solénoïdes peuvent être utilisés conjointement sur une surface de détection à condition que l’intelligence de celle-ci soit capable d’activer chaque solénoïde indépendamment des autres.
La capture de l’orientation d’éléments mobiles hybrides peut donc être obtenue en dotant chaque élément mobile hybride d’au moins deux modules de localisation (ne devant pas être alignés selon une perpendiculaire à la surface de détection) et en définissant une règle d’identification de ces modules de localisation. L’activation séquentielle de modules de localisation, par l’élément de sol, permet d’estimer la position et/ou l’orientation d’une pluralité d’éléments mobiles hybrides pourvus de ces modules de localisation.
Lorsqu’un module de localisation reçoit une commande d’activation qui lui est dédiée, il déclenche une émission électromagnétique. Le système de détection, connaissant l’identification du module de localisation en cours d’émission, peut alors lier les informations de position calculées à l’identifiant du module de localisation.
Il est ainsi possible de construire un tableau contenant, pour chaque élément mobile hybride, un identifiant, une abscisse, une ordonnée et, de préférence, une altitude dans un repère de la surface de détection. L’activation séquentielle de l’émission électromagnétique des modules de localisation permet l’utilisation d’une unique fréquence d’émission pour l’ensemble des éléments mobiles hybrides gérés par le système.
La figure 6 illustre schématiquement des blocs logiques d’un élément mobile hybride dont la position peut être déterminée à partir d’un dispositif d’interfaçage (ou élément de sol) tel qu’illustré sur la figure 2.
Un tel élément mobile hybride est, de préférence, autonome tant en ce qui concerne son alimentation électrique que la réception de signaux de commande d’émission électromagnétique.
Dans cet exemple, on considère un élément mobile hybride comprenant un unique module de localisation, comme sur la figure 5a. L’homme du métier pourra sans difficulté adapter le présent enseignement à un élément mobile hybride comprenant deux ou plus de modules de localisation (comme représenté sur la figure 5b). L’élément mobile hybride comprend ainsi un module d’alimentation électrique 601 fournissant une tension pour l’ensemble des composants du module de localisation ainsi qu’un module de réception et détection de commande 602 qui reçoit et démodule un signal, par exemple un signal HF, émis par un module externe de l’élément de sol, pour déterminer si le signal reçu vise l’activation de ce module de localisation. Comme décrit précédemment, une telle détection peut être réalisée par la comparaison d’un identifiant reçu avec un identifiant préalablement mémorisé. L’élément mobile hybride 600 comprend en outre un commutateur 603, commandé par le module de réception et détection de commande 602, ainsi qu’un amplificateur sélectif 604 commandé par le commutateur 603. Enfin, l’élément mobile hybride 600 comprend un oscillateur local 605 générant une fréquence, de préférence, fixe, stable et de type carré et un solénoïde 606. L’élément mobile hybride 600 comprend également une centrale inertielle 607 et des moyens de communication 608 avec les moyens de communication 228 de l’élément de sol 101. En variante, les moyens de communication 608 pourraient être rattachés ou confondus avec le récepteur HF 602 et communiquer avec l’émetteur HF 227 de l’élément de sol. L’élément mobile hybride comprend une unité de traitement 609 configurée pour récupérer les données de déplacement brutes de la centrale inertielle 607, les mémoriser dans une mémoire de l’élément mobile hybride (non représentée) et pour commander leur envoi via les moyens de communication 608.
Dans certains modes de réalisation, comme par exemple celui décrit en référence aux figures 4c et 4d, l’unité de traitement 609 est configurée pour mettre en œuvre des calculs hybride d’informations de position tels que décrits précédemment.
En variante, la centrale inertielle 607 peut intégrer une telle intelligence, c’est-à-dire intégrer l’unité de traitement 609. L’amplificateur sélectif 604 génère, selon la position du commutateur 603 et à partir du signal issu de l’oscillateur local 605, une tension sinusoïdale aux bornes du solénoïde 606, permettant au solénoïde 606 de générer une certaine puissance de rayonnement.
Plusieurs types d’alimentation électrique 601 peuvent être utilisés. L’alimentation peut être obtenue à partir d’une batterie rechargeable et un circuit de contrôle standard. Elle peut également être obtenue à partir d’une batterie et d’un régulateur de tension permettant d’obtenir une tension constante durant toute une plage d'utilisation de la batterie. Cette solution est particulièrement avantageuse lorsque le système doit calculer l’altitude d’éléments mobiles hybrides mis en œuvre. L’alimentation peut également être fournie de façon indirecte, par télé-alimentation couplée avec l’utilisation de moyens de stockage d’énergie.
Selon ce mode de réalisation, une couche de solénoïdes rayonnants dédiés est placée sous la surface de détection. Ces solénoïdes sont parcourus par un signal sinusoïdal et la puissance émise par chaque solénoïde est suffisante pour télé-alimenter les modules de localisation positionnés au-dessus de lui. Les modules de localisation sont également équipés d'un solénoïde pour la réception, par induction, du signal émis par les solénoïdes présents sous la surface de détection. D’autres moyens de télé-alimentation peuvent être utilisés, par exemple des antennes utilisant la technologie Powercast (Powercast est une marque).
Les moyens de stockage d’énergie comprennent par exemple un condensateur de forte capacité qui est chargé à partir du solénoïde du module de localisation. Le condensateur est utilisé comme source de tension pour alimenter les autres modules.
Alternativement, les moyens de stockage d’énergie comprennent une batterie présente dans l’élément mobile hybride, par exemple une batterie au lithium. Le solénoïde du module de localisation recharge alors constamment cette batterie dès qu'il est parcouru par un courant induit. Un circuit de protection de charge/décharge est avantageusement associé à la batterie pour qu’elle reste dans sa plage de tensions acceptables. Si l’altitude d’éléments mobiles doit être évaluée, la source de tension est, de préférence, régulée pour que la tension d'alimentation soit constante durant une durée d'utilisation de cette source de tension, c'est-à-dire durant une estimation de position et/ou d’orientation de l’élément mobile hybride.
Les éléments mobiles hybrides situés sur une surface de détection et utilisés conjointement peuvent utiliser des types d’alimentation différents.
Par ailleurs, lorsqu’un élément mobile hybride comprend plus d’un module de localisation, certains composants, notamment l’alimentation électrique, peuvent être communs à certains ou à tous les modules de localisation.
La figure 7 illustre un exemple d’application dans laquelle des éléments mobiles hybrides selon l’invention peuvent être avantageusement utilisés.
Dans un environnement 700, l’utilisateur est équipé d’un système de réalité augmenté ou réalité virtuelle comprenant un casque 701, par exemple de type HMD (sigle de Head-Mounted Display en terminologie anglo-saxonne).
Ce système comprend par exemple une centrale inertielle 702 solidaire du casque 701 et intégrant par exemple un ou plusieurs magnétomètres, accéléromètres, gyromètres. Ainsi, les données de déplacement issues de la centrale inertielle 702 permettent de décrire le déplacement du casque 701 selon plusieurs degrés de liberté, par exemple six degrés de liberté.
Dans cet exemple, l’utilisateur est équipé à chaque pied d’un élément mobile hybride 703 et 704 tel que décrit précédemment et se déplace sur un élément de sol 705 similaire à l’élément de sol 101 décrit précédemment. Il est ici rappelé que l’invention n’est toutefois pas limitée à un dispositif d’interfaçage localisé au sol, mais qu’elle couvre également des cas où le dispositif d’interfaçage est disposé sur des murs latéraux ou au plafond.
Ainsi, par application des méthodes décrites précédemment, il est possible de suivre la position des deux pieds de l’utilisateur dans le repère de l’élément de sol 705.
Avantageusement, les données de position ainsi obtenues permettent de recaler la centrale inertielle 702 localisée au niveau du casque 701.
Par exemple, en supposant que l’utilisateur se déplace de manière à ce que la distance D entre le casque 701 et l’élément de sol 705 est constante, alors la centrale inertielle 702 peut être recalée à l’aide des informations de position calculées au niveau des pieds de l’utilisateur, la composante dans la direction perpendiculaire au plan de l’élément de sol étant translatée de la distance D.
En variante, il est possible de placer un moyen de mesure de l’altitude (baromètre ou télémètre) au niveau du casque 701. Ceci permet de recaler les données de la centrale inertielle 702, même si l’altitude (distance D) varie dans le temps.
Le recalage de la centrale inertielle 702 peut aussi se faire plus précisément si on implémente un modèle de cinématique inverse lié au corps humain.
Il est rappelé que la cinématique inverse permet par exemple, pour un modèle humain, de déterminer la torsion de la colonne vertébrale, des chevilles, des genoux, du cou, ou de tout autre articulation du corps humain, à partir des trajectoires ou des positions des mains ou des pieds. Plutôt que de spécifier manuellement un ensemble de coordonnées articulaires, un modèle de cinématique inverse permet de formuler un mouvement du squelette à partir de ses composants significatifs, par exemple la trajectoire respective des mains ou des pieds, l’orientation du bassin.
Lorsqu’il tel modèle de cinématique inverse est utilisé, la connaissance des données de position des pieds par les éléments mobiles hybrides 703 et 704 ainsi que les données issues de la centrale inertielle 702 permet de calculer la position des différentes parties qui composent le corps humain (jambes, colonne vertébrale, cou, tête). On obtient ainsi une position plus précise de l’élément 702 par rapport aux éléments 703 et 704 grâce à ce modèle de cinématique inverse.
Les figures 8 et 9 illustrent des variantes de réalisation de la figure 7, selon lesquelles il est possible de calculer plus précisément la position des différentes parties du corps humain de l’utilisateur. Bien entendu, l’invention peut aussi avantageusement s’appliquer à la localisation précise des différents membres d’un robot ou de tout autre objet complexe, par exemple articulé.
Dans les exemples représentés sur les figures 8 et 9, l’utilisateur se déplace dans un environnement 800 (figure 8), respectivement 900 (figure 9). Il est équipé d’un système de réalité augmenté ou réalité virtuelle comprenant un casque 801 (figure 8), respectivement 901 (figure 9), similaires à 701 (figure 7).
Il s’agit par exemple d’un casque de type HMD (sigle de Head-Mounted Display en terminologie anglo-saxonne).
Egalement, le système comprend une centrale inertielle 802 (figure 8), respectivement 902 (figure 9), similaires à 702 (figure 7), solidaire du casque 801, respectivement 901. La centrale inertielle intègre par exemple un ou plusieurs magnétomètres, accéléromètres, gyromètres.
Ainsi, les données de déplacement issues de la centrale inertielle 802, respectivement 902 permettent de décrire le déplacement du casque 801, respectivement 901 selon plusieurs degrés de liberté, par exemple six degrés de liberté. L’utilisateur est en outre équipé à chaque pied d’un élément mobile hybride 803 et 804 (figure 8), respectivement 903 et 904 (figure 9) similaires à 703 et 704 (figure 7) et se déplace sur un élément de sol 805 (figure 8), respectivement 905 (figure 9), similaires à 705 (figure 7).
Dans l’exemple de la figure 8, l’utilisateur est en plus équipé à la ceinture d’une autre centrale inertielle 808, et sur le casque 801, d’un moyen 809 de mesure de l’altitude du casque 801 comme par exemple un télémètre ou un baromètre.
Un télémètre visant vers le haut permet par exemple de mesurer la distance de la tête de l’utilisateur par rapport au plafond et au final de calculer l’altitude de la tête de l’utilisateur par la connaissance de la distance sol / plafond. Un baromètre permet quant à lui de mesurer l’altitude à partir de la pression de l’air.
Avantageusement, par application des méthodes décrites précédemment, il est possible de suivre la position des deux pieds de l’utilisateur équipés des éléments mobiles hybrides 803, 804, dans le repère de l’élément de sol 805.
La connaissance de l’altitude la tête de l’utilisateur grâce au moyen 809 permet de connaître la position du casque même si la distance D entre le casque 801 et l’élément de sol 805 varie en temps réel, ce qui arrive par exemple lorsque l’utilisateur se baisse ou saute par rapport à l’élément de surface 805.
Les données issues de la centrale inertielle 802 peuvent être recalées à l’aide des informations de position calculées au niveau des pieds de l’utilisateur, la composante dans la direction perpendiculaire au plan de l’élément de sol étant translatée de la distance D qui varie dynamiquement.
Le recalage de la centrale inertielle 802 peut aussi se faire plus précisément si on implémente un modèle de cinématique inverse lié au corps humain. Dans ce cas, la connaissance des données de position des pieds par les éléments mobiles hybrides 803 et 804 ainsi que les données issues de la centrale inertielle 802 permettent de calculer la position des différentes parties qui composent le corps humain Gambes, colonne vertébrale, cou, tête), étant entendu que les différents éléments 801 à 804, 808 et 809 sont capables de communiquer ensemble.
Ainsi, la centrale inertielle 808 permet d’obtenir un modèle de cinématique inverse encore plus précis, puisqu’il permet d’obtenir des données de position du milieu du corps et augmente donc la précision du modèle de cinématique inverse.
Dans l’exemple de la figure 9, l’utilisateur est équipé d’un système magnétique (champs magnétiques constants ou pulsés) constitué d’un émetteur magnétique 908 émettant un champ magnétique dans une pluralité de directions (préférentiellement dans trois directions perpendiculaires) ainsi que d’une pluralité de récepteurs (capteurs) magnétiques 909, 910 et 911. Par exemple, un tel système est connu sous le nom de Polhemus Fastrak (Polhemus Fastrak est une marque) et Razer Hydra (Razer Hydra est une marque). L’émetteur comprend par exemple trois solénoïdes émettant chacun un champ magnétique dans des directions orthogonales.
Comme représenté sur la figure 9, l’émetteur 908 est par exemple localisé au niveau de la ceinture de l’utilisateur. Le récepteur 909 est localisé au niveau de la tête de l’utilisateur, par exemple sur le casque 901. Les récepteurs 910 et 911 (qui sont par exemple des manettes) sont localisés dans les mains de l’utilisateur. Dans son principe, le système magnétique (constitué des éléments 908 à 911) permet d'obtenir les coordonnées de chaque récepteur 909, 910 et 911, dans le repère de l’émetteur 908, ceci de manière fiable et déterministe.
Les différents éléments 901 (casque), 903 (élément mobile hybride), 904 (élément mobile hybride) et 908 (émetteur magnétique) communiquent ensemble.
La position de l’émetteur 908 par rapport aux pieds équipés des éléments mobiles hybrides 903 et 904 peut être obtenue en faisant l’hypothèse que la distance D entre l’émetteur 908 et l’élément de sol 905 est constante. Ainsi la composante de la position de l’émetteur 908 dans la direction perpendiculaire au plan de l’élément de sol 905 peut être obtenue par une simple d’une translation de la distance D.
Selon une variante, il est possible de placer un télémètre ou un baromètre (similaires à 809 sur la figure 8) au niveau de l’émetteur 908, afin de mesurer une altitude dynamique, c’est-à-dire une distance D variable entre l’émetteur 908 et l’élément de sol 905. Ceci est notamment avantageux pour les cas où l’utilisateur saute ou se baisse par rapport à l’élément de sol 905.
Ainsi, des méthodes selon l’invention permettent de calculer la position de l’émetteur 908 dans le repère de l’élément de sol 905.
De plus, il est possible de connaître les positions respectives des récepteurs 909, 910 et 911 dans ce même repère, grâce à la réception des coordonnées des récepteurs dans le repère de l’émetteur 908.
Avantageusement, grâce à l’utilisation du système magnétique décrit, les positions des mains de l’utilisateur (récepteurs 910 et 911) peuvent être connues en temps réel et la connaissance de la position de la tête (récepteur 909) permet de recaler avec une très bonne précision les données de la centrale inertielle 902 dans le repère de l’élément de sol 905, par exemple comme décrit précédemment en référence à l’étape 406 de la figure 4a.
Bien entendu le recalage de la centrale inertielle 902 peut aussi se faire plus précisément si on implémente un modèle de cinématique inverse lié au corps humain. Dans ce cas, la connaissance des données de position des pieds par les éléments mobiles hybrides 903 et 904 ainsi que les données issues de la centrale inertielle 902 et la position du récepteur 909 dans le repère de l’élément de sol 905 permettent de calculer la position des différentes parties qui composent le corps humain (jambes, colonne vertébrale, cou, tête).
Ainsi, dans les exemples des figures 8 et 9, la connaissance des données de position des pieds par les éléments mobiles hybrides (803 et 804 sur la figure 8 ; 903 et 904 sur la figure 9) ainsi que les données issues des centrales inertielles (802 et 808 sur la figure 8, 902 sur la figure 9) et du système magnétique (figure 9), permettent de calculer de manière fiable la position de différentes parties du corps humain (jambes, colonne vertébrale, cou, tête). On obtient ainsi une position plus précise du casque (801, 901) ainsi que des autres équipements par rapport aux éléments mobiles hybrides 803, 804, respectivement 903, 904.
Naturellement, pour satisfaire des besoins spécifiques, une personne compétente dans le domaine de l’invention pourra appliquer des modifications dans la description précédente.
FIELD OF THE INVENTION
The present invention relates to the location of mobile elements by a computer system, particularly in the field of intelligent floors. It has particular applications in the field of virtual reality or augmented reality. More particularly, the invention relates to a hybrid mobile element, a device and a method for interfacing a plurality of hybrid mobile elements with a computer system.
BACKGROUND OF THE INVENTION
In many situations, it may be necessary for a computer system to detect the location (eg position, orientation, altitude) of moving elements to allow the moving elements to respond accordingly, and to allow the use of these elements. mobile devices as the interface of a computer system.
The present invention is particularly interested in the detection of mobile elements for example worn by human users or robots. These users can for example move on a playground, or inside a building. In addition, these users can perform movements of large amplitude, which imposes particular constraints, particularly in terms of position tracking.
Locating systems are available for continuous monitoring of large displacements.
One solution is to use an inertial unit, which is defined as a set of sensors (for example, gyroscopes and accelerometers, magnetometers) for measuring parameters of the movement of a movable element. However, in practice, the operation deviates from the ideal equations because of the errors that affect the measurements of rotations and accelerations (for example bias, noise, scale factors, non-linearities) and which generate drifts during time estimates for example the speed and position of the mobile element considered. Also, shocks to the moving element can cause significant errors in the measurements of the inertial unit.
Thus, such a solution is not suitable for applications whose duration exceeds a few minutes or even a few seconds, such as for example applications of virtual reality or augmented reality.
Another possible solution not suffering from such a drift is the location by a differential GPS (Differential Global Positioning System) which uses a network of reference fixed stations transmitting to a receiver the difference between the positions indicated by the satellites. and their known real positions. The receiver thus receives the difference between the pseudodistances measured by the satellites and the real pseudo-distances and can thus correct its own measurements.
However, this type of location is not adapted to the location of mobile elements located inside a building. In addition, the precision of the differential GPS is of the order of ten centimeters, which may be insufficient for some applications, including virtual reality or augmented reality. In addition, this technology is very sensitive to the presence of metal objects, which can distort the position measurements.
There are other localization technologies, including those using terrestrial triangulation, for example UWB (Ultra Wide Band English) or iBeacon, allowing the location of elements inside buildings. In principle, these technologies are used for positioning mobile devices carrying tags capable of transmitting data received by receivers distributed in the environment, for example inside a building. These receivers evaluate the distance separating them respectively from the beacons by measuring the propagation time of the signals, which enables the system to calculate the position of the mobiles by triangulation.
These technologies have the disadvantage of requiring calibration tags. In addition, the accuracy of the position calculated by triangulation is of the order of 15 cm, which may be insufficient for certain applications, for example virtual reality or augmented reality. In addition, the triangulation methods used are poorly suited to the location of a plurality of elements, problems of congestion of the system being rapidly observed. These technologies are also sensitive to the presence of metal elements (for example metal-walled partitions, metal girders or metal cabinets) which considerably disturb the position measurements due to the multiple paths of the waves. The presence of these metal elements greatly reduces the accuracy of the final calculation of the position (accuracy of more than 1 m).
In the particular field of virtual reality and augmented reality applications, there are location solutions based on optical means, including cameras.
However, these solutions require special installations (eg LED rails to be placed in the environment, many cameras sometimes carrying calculating means for the analysis of real-time images, or even constellations of infrared targets allowing cameras to calculate positions) and often very expensive so unrealistic for consumer applications. In addition, these solutions are particularly sensitive to the environment in which the mobile element evolves, including the visual quality of the environment, which can be altered for example by smoke, fog, or low light. They are also sensitive to the masking of the optical means by physical obstacles, typically by another mobile element, and are therefore unsuitable for tracking over time a plurality of mobile elements.
SUMMARY OF THE INVENTION The invention solves at least one of the problems discussed above. The invention thus relates to a hybrid mobile element for a device for interfacing a plurality of hybrid mobile elements with a computer system, said hybrid mobile element comprising at least one location module comprising the following means: means for transmitting an electromagnetic signal for calculating (or determining) the position of said location module; and, means for receiving an activation signal and, according to at least one information of said activation signal, activating said means for transmitting an electromagnetic signal; said hybrid mobile element being characterized in that it further comprises: an inertial unit integral with said location module; and - means of communication with said device, for transmitting data relating to a displacement of the inertial unit. The hybrid mobile element according to the invention thus enables a computer system to simply and effectively determine the position of a large number of mobile elements that can be used to interact with this computer system, even when some of these mobile elements are momentarily out of reach of the interfacing device so that their location module can not send signal at any given time.
Indeed, thanks to the use of an inertial unit integral with a given location module, although it can not emit a signal to directly calculate a position information, it is nevertheless possible to calculate this information of position from displacement data of the inertial unit and an earlier position information calculated at a time when the device could receive a signal from this location module. This type of calculation, since it is based on two types of data, namely a position information computed from a signal received from the location module and displacement data from the integral inertial unit of this module, is called hybrid calculation.
Advantageously, the position information that can be derived from the displacement data of the inertial unit will be representative of the position of the hybrid mobile element since it is fixed relative to (rigidly linked with) the inertial unit.
Moreover, the combined use of the inertial unit and the location module makes it possible to avoid the data drift phenomenon of the inertial unit.
According to a particular embodiment, the communication means of the hybrid mobile element are further configured to receive at least one position information of said location module. For example, this position information has been calculated by the device from electromagnetic signals emitted by the location module.
According to a particular embodiment, the hybrid calculation of the position is performed at the hybrid mobile element.
In this mode, the hybrid mobile element further comprises hybrid computing means of new position information of said location module, from the received position information and the displacement data of the inertial unit.
The communication means can then be further configured to transmit said new position information of said location module, for example to the device.
According to a particular embodiment, the communication means of the hybrid mobile element are configured to receive data for resetting the displacement data of the inertial unit, said resetting data being based on position information calculated from a electromagnetic signal emitted by said location module.
These registration data are for example a position information calculated by the device from electromagnetic signals transmitted by the location module at a given instant.
According to a particular embodiment, the hybrid mobile element is configured to reset the displacement data of the inertial unit with each activation of the location module. In this mode, each position information calculated by the device from electromagnetic signals transmitted by the location module is sent to the hybrid mobile element.
The means for transmitting a signal comprise, for example, a solenoid emitting an electromagnetic field when it is activated, to make it possible to determine the position and / or the orientation of the hybrid mobile element. In a variant, the means for transmitting the signal may comprise any other means for emitting an electromagnetic field. The hybrid mobile element may further comprise remote power supply means for electrically powering the components of the location module.
For example, the hybrid mobile element may comprise at least one solenoid, excitable by induction. The hybrid mobile element may comprise any other remote power supply means, for example antennas using Powercast technology (Powercast is a trademark). The hybrid mobile element may include energy storage means such as a battery, a battery, or a capacitor. The invention also relates to a device for interfacing a plurality of hybrid mobile elements with a computer system, the device comprising a detection surface and being characterized in that it comprises the following means: means for activating sequentially at least a location module integrated with each hybrid mobile element of said plurality of hybrid mobile elements, a single location module being able to be activated at a given time; means for receiving at least one electromagnetic signal from said at least one activated location module; means for calculating in real time, from said at least one electromagnetic signal received, at least one position information, in a reference frame associated with said detection surface, of a hybrid mobile element comprising said activated location module; communication means for receiving data relating to a displacement of an inertial unit integral with said at least one activated location module in the absence of reception of an electromagnetic signal upon activation of said at least one location module; means for real-time hybrid computation, from the received displacement data and the calculated position information, of new position information of said at least one activated location module.
According to a particular embodiment, the communication means of the device are further configured to: transmit the position information calculated from the received electromagnetic signal to the hybrid mobile element; and - to receive said new position information, calculated by the hybrid moving element from the transmitted position information.
According to a particular embodiment, the communication means of the device are configured to transmit data for resetting the displacement data of the inertial unit, said resetting data being based on position information calculated from an electromagnetic signal received. .
These registration data are for example a position information calculated by the device from electromagnetic signals transmitted by the location module at a given instant. The invention also relates to a device comprising a plurality of devices as described above, a device of the plurality of devices controlling at least some means implemented in the other devices of the plurality of devices. It is thus possible to increase the size of the surface on which the mobile hybrid elements can evolve.
Advantageously, the means for sequentially activating at least one location module could comprise means for transmitting a high frequency signal comprising an identifier of a location module. The device could thus easily select a particular location module according to its identifier.
The received signal could for example be an electromagnetic field. The means for receiving at least one signal from an activated location module could also comprise a conductive gate formed of a set of conductive loops, and the device could then comprise means for sequentially selecting each conducting loop of this set of conductive loops. . It would thus be possible to determine the position of a location module according to characteristics of the received signals and selected conductive loops.
Advantageously, the device could also comprise means of filtering the received signal in order to eliminate the parasitic signals.
The detection surface comprises for example a PET plastic surface on which the conductive grid has been formed by silver screen printing. For example, the conductive grid was formed by printing using a conductive ink jet containing silver particles.
In a variant, the detection surface comprises, for example, a PET plastic surface on which the conductive grid has been formed with copper tracks. According to another variant, the conductive grid is formed by weaving with a conductive wire.
According to yet another variant, the detection surface comprises for example a PCB type PCB (acronym Printed Circuit Board in English terminology) for electromagnetic reception, flexible or rigid. The invention also relates to a method for interfacing a plurality of hybrid mobile elements with a computer system, the method being characterized in that it comprises the following steps: - obtaining at least one position information of a hybrid mobile element of said plurality, said hybrid mobile element comprising at least one activated location module, the at least one position information being calculated from at least one electromagnetic signal emitted by said at least one integrated activated location module the hybrid mobile element, a single location module that can be activated at a given time; then, in the absence of subsequent reception of an electromagnetic signal upon activation of said at least one location module: obtaining data relating to a displacement of an inertial unit integral with said at least one activated location module; and - real-time hybrid computation, from the displacement data obtained and the position information obtained, of new position information of said at least one activated location module.
According to a particular embodiment, the method further comprises a step of resetting the displacement data of the inertial unit.
This data is for example calculated from one or more position information calculated from signals received from the location module.
According to a first embodiment, the method further comprises a step of storing said position information obtained with the date of its calculation, said resetting step being implemented from said stored position information.
According to a second embodiment, the method further comprises a step of receiving information indicating a failure to receive an electromagnetic signal from said at least one activated location module.
In this second mode, the method may further comprise a step of receiving registration data, said resetting step being implemented from the received registration data.
In this second mode, the method may further comprise a step of transmitting the new calculated position information. The hybrid mobile element or the device, depending on the modes, can thus readjust the displacement data of the inertial unit with the aid of the registration data. This avoids the problems of drift over time sometimes observed during the prolonged use of an inertial unit or shock suffered by it.
Advantageously, such a method could further include a step of checking the validity of the at least one location module, the sequential activation step of the location module being performed in response to the validity check step. Thus, only the positions and / or orientations of the hybrid moving elements located in the (electromagnetic) range of the detection surface would be determined.
Such a method could also include a step of assigning a state of validity or invalidity to the location module, the state of validity or invalidity being determined according to the position information or information.
The method could also include a step of sequentially selecting a plurality of receivers, said at least one signal being received from at least one selected receiver in the plurality of receivers. It would thus be possible to determine the position of a location module according to characteristics of the received electromagnetic signals and the selected receivers. The subject of the invention is also an assembly for a virtual or augmented reality system intended to equip a user in motion, said system comprising: at least one hybrid mobile element as mentioned above, adapted to be worn by the user; at least one interfacing device as mentioned previously; a virtual or augmented reality headset adapted to be worn by the user, said headset being connected to said hybrid mobile element or to said interfacing device so as to enable the position of the headset to be tracked as a function of the relative position of the headset; the hybrid mobile element and helmet and the position of the hybrid mobile element.
According to a particular embodiment, this assembly further comprises a magnetic positioning system comprising means for transmitting a magnetic field in a plurality of directions and a plurality of means for receiving said magnetic field emitted by the transmitting means. said magnetic positioning system being configured to determine the position of at least one of the receiving means in a coordinate system centered on the transmitting means, from the magnetic field received by said receiving means.
BRIEF DESCRIPTION OF THE FIGURES Other advantages, objects and features of the present invention will become apparent from the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings, in which: FIG. 1, composed of FIGS. and 1b, schematically illustrates a context in which embodiments of the invention may advantageously be implemented; FIG. 2 illustrates an example of an interfacing device according to a particular embodiment; FIG. 3, composed of FIGS. 3a and 3b, schematically illustrates the physical principle of inductive coupling between a solenoid and a conductive loop of a detection surface (FIG. 3a), as well as an interpolation mechanism (FIG. 3b). for determining the position of a solenoid placed on a detection surface, along a given axis, from the measurements obtained by a system such as that described with reference to Figure 2; FIGS. 4a and 4b are flowcharts showing steps implemented respectively by a device (FIG. 4a) and a hybrid mobile element (FIG. 4b) according to a first embodiment of the invention; FIGS. 4c and 4d are flow charts representing steps implemented respectively by a device (FIG. 4c) and a hybrid mobile element (FIG. 4d) according to a second embodiment of the invention; FIGS. 5a and 5b schematically illustrate two examples of hybrid mobile elements whose position can be determined and whose position and orientation can be determined, respectively, according to particular embodiments of the invention; FIG. 6 schematically illustrates logic blocks of a hybrid mobile element whose position can be determined from an interfacing device as illustrated in FIG. 2; FIGS. 7, 8 and 9 illustrate three examples of applications in which hybrid mobile elements according to the invention can advantageously be used.
DETAILED DESCRIPTION OF THE INVENTION
In general, the object of the invention is to determine the position (abscissa, ordinate and / or altitude) and / or orientation (heading, pitch and / or roll) of hybrid mobile elements used jointly, and for example worn. by a user (or a robot) capable of making large movements.
There are solutions for detecting the position and / or orientation of a plurality of real objects, especially when they are located near or on a game board for using these objects as interface of a system computer. For example, French Patent No. 1057014 proposes such a solution. Unfortunately, this solution makes it possible to calculate such position information only insofar as these objects are in the detection field of a detection surface, for example less than ten centimeters from this detection surface.
In what follows, the detection range of a detector is defined as a space-limited area, in which an electromagnetic field emitted by a transmitter located in this area can be detected by a detector. Thus, when the transmitter leaves the detection range of the detector, the detector will not be able to pick up an electromagnetic field emitted by the transmitter.
Thus, a hybrid mobile element carried by a user moving on a floor consisting for example of a set of detection surfaces (also called smart floor) can, by the movements of the user (or robot), substantially move away from the detection surface and out of its detection range, so that tracking of this hybrid mobile element by the computer system can not be continuous.
Also, when the detection surfaces only partially cover a building, for example for cost reasons, there may be discontinuities in the tracking of the position of the hybrid mobile element, especially when the user (or the robot) which carries it enters an area not covered by a detection surface.
In order to allow the tracking of such mobile elements, especially when they are worn by one or more users (or robots) performing movements of large amplitude, the invention provides a hybrid mobile element provided with at least one integrated location module an inertial unit whose autonomous operation makes it possible to obtain displacement data, as well as communication means (transmitter-receiver) with the detection surface.
When such a hybrid mobile element is outside the detection range of the detection surface, position information of its location module can nevertheless be obtained from displacement data of the inertial unit secured to the location module. Such a determination mode is called hybrid calculation of the position information, since it is based on both the displacement data of the inertial unit, but also on a position information previously calculated when the location module was in the detection range.
In the context of the present invention, several embodiments are envisaged for the hybrid calculation.
According to a first embodiment, the hybrid calculation is performed at the detection surface. In this mode, displacement data measured by the inertial unit are directly transmitted to the detection surface via the communication means. New position information is then calculated by the detection surface from these displacement data and previously calculated position information.
According to a second embodiment, the hybrid calculation is performed at the hybrid mobile element. In this mode, the detection surface sends previously calculated position information to the hybrid mobile element. This position information has typically been calculated from an electromagnetic signal received from the location module while in the detection range of the detection surface. This is for example the last position calculated before the hybrid mobile element exits the scope of the detection surface. The hybrid mobile element then calculates new position information using the received position information and displacement data measured by the inertial unit. This hybrid position is then transmitted via the communication means provided on the hybrid mobile element.
Thus, the displacement data obtained by virtue of the autonomous operation of the inertial unit enable the position of the hybrid mobile element to be monitored, even when the location module that it integrates momentarily leaves the scope of the detection of the surface of the inertial unit. detection.
In addition, when the locating module of a hybrid mobile element is in the detection range of the detection surface, it is possible to calculate location information of the locator module with a certain reliability, which allows to reset the displacement data of the associated inertial unit, for example with registration data based on these reliable position information.
Figure 1, consisting of Figures 1a and 1b, schematically illustrates a context in which embodiments of the invention may be implemented. The applications of the present invention are not limited to the example illustrated in this figure. A hybrid mobile element according to the invention can indeed equip any type of object (worn clothing, robot, joystick, etc.).
In particular, Figures 1a and 1b show the same scene but at two different times.
In this scene, a user whose only shoes 102 and 103 are shown, is on a floor element 101 (or interfacing device) according to embodiments of the invention. Even if in this example, the interfacing device is a floor element, the invention is not limited to interfacing devices placed at ground level. In the following, all that is described with reference to the floor element 101 can be easily transposed by the skilled person to any interfacing device placed elsewhere than the ground, for example on side walls or ceiling . The floor element 101 comprises, for example, a material module as well as a detection surface as described with reference to FIG. 2. Because of its structure, this detection surface has a limited detection range, for example of the order of ten centimeters.
The hardware module of the floor element 101 comprises communication means (transceiver), for example a wireless communication module of WIFI or Bluetooth type or communicating in an ISM band (acronym for Industrial, Scientific and Medical) for example 2.4 GHz. These communication means allow the ground element to interact with hybrid mobile elements in accordance with embodiments.
For example, these communication means may correspond to a radio transmitter enabling activation of a locating module of a hybrid mobile element, as described with reference to FIG. 2, so that it emits an electromagnetic field that is useful in the calculation of his position.
The hardware module of the floor element 101 further comprises a calculation module comprising a central processing unit. This processing unit controls for example the aforementioned communication means.
In this example, each shoe 102 (respectively 103) is equipped with a hybrid movable member 104 (respectively 105) according to embodiments of the invention. Of course, the invention is not limited to two hybrid mobile elements and a much larger number of hybrid mobile elements can be supported by the same floor element 101.
These hybrid mobile elements each comprise at least one location module as described with reference to FIGS. 5 and 6.
According to particular embodiments of the present invention, the hybrid mobile elements 104 and 105 further comprise an inertial unit integral with each location module. Thus a given inertial unit is fixed relative to the associated location module.
Such an inertial unit comprises for example one or more accelerometers, one or more magnetometers, and / or one or more gyrometers. Thus, an inertial unit makes it possible to obtain displacement data such as, for example, a rotation speed at a given instant around a certain axis, an acceleration at a given instant along a certain axis, or an estimate of the direction of travel. magnetic field at a given moment.
Still according to particular embodiments of the present invention, the hybrid mobile elements 104 and 105 respectively comprise means of communication (not shown) wireless WIFI or Bluetooth type or communicating in an ISM band (acronym for Industrial, Scientific and Medical) for example 2.4 GHz. These communication means allow the hybrid mobile elements to interact with the corresponding communication means of the floor element 101.
For example, these communication means may correspond to an activation control radio transmitter / receiver, as described with reference to FIG. 6.
Alternatively, it may be separate means. For example, the inertial unit may comprise these communication means.
When the shoes 102 and 103 of the user are placed on the floor element 101, as shown in FIG. 1a, the hybrid mobile elements 104 and 105 that they carry are in the detection range of the floor element 101.
It is therefore possible to sequentially activate the location modules of the hybrid mobile elements 104 and 105 and determine their respective position by implementing a calculation step based on the signals (magnetic fields) received from these location modules, such as described with reference to FIG.
On the other hand, when the user moves one of his shoes, for example the shoe 102, as shown in FIG. 1b, the hybrid mobile element 104 carried by it can leave the detection range of the floor element. 101.
When the hybrid mobile element leaves the detection range of the ground element as is the case in FIG. 1b, it can not receive a signal (magnetic field) emitted by the activated location module and therefore can not determine the position of this module from it.
There are other situations in which the hybrid moving element leaves the detection range, for example when a room is equipped with one or more floor elements (intelligent floor) such as the floor element 101, covering the floor surface discontinuously. Thus, when a user is on a surface not provided with a floor element, the hybrid mobile element that he wears can almost always be out of reach of the floor elements equipping the room. The hybrid mobile element according to the invention advantageously allows the floor element 101 not to lose, however, the tracking of the position of this hybrid mobile element when such situations occur.
Indeed, as mentioned above, the hybrid mobile element comprises an inertial unit integral with the location module, so that the displacement of this location module can be measured autonomously by the inertial unit.
The communication means of the hybrid mobile element are not subject to the detection range of the floor element 101, which makes it possible to transmit displacement data from the inertial unit to the floor element 101 by this method. bias when the hybrid moving element is out of range. From these received data, the ground element 101 can calculate the position of the hybrid mobile element whose electromagnetic signal emitted by the activated location module could not be received, by implementing a calculation step hybrid based on the received data, as described with reference to FIG. 4.
As a variant, the communication means of the hybrid mobile element make it possible to receive, from the ground element, position information previously calculated from a signal transmitted by the location module at a time when it was in the detection range of the floor element. From this position information and the displacement data of the inertial unit, the hybrid mobile element calculates the position of the associated location module, by implementing a hybrid calculation step based on the received data, as described in FIG. reference to Figure 4.
FIG. 2 illustrates an example of an interfacing device according to a particular embodiment. The floor element or interfacing device comprises a detection surface 210 constituted by a mesh in the form of rows and columns constituting a conductive grid. The latter comprises a set of conductive loops along two orthogonal axes. Each loop is a sensor for measuring the intensity of the current or the voltage induced by a solenoid (belonging to a hybrid moving element whose position and / or orientation must be calculated) which is positioned on the detection surface.
Advantageously, the detection surface may be a PET plastic surface on which the conductive grid has been formed by silver screen printing. For example, the conductive grid was formed by printing using a conductive ink jet containing silver particles. Alternatively, the detection surface is for example a PET plastic surface on which the conductive grid has been formed with copper tracks. Alternatively, the conductive grid is formed by weaving with a conductive wire.
Alternatively, the detection surface may be a PCB type PCB (acronym Printed Circuit Board in English terminology) for electromagnetic reception, flexible or rigid. By way of illustration, it is admitted here that a solenoid is placed at position 211, that is to say at the intersection of loops 212 and 213, one end of which is connected to a mass and the other end. is connected to the electronic components used to calculate a position. When the solenoid at position 211 is energized, it generates an inductive current in loops 212 and 213 which can be analyzed and compared to the current induced in the other loops. It is thus possible, by inductive coupling between the solenoid and the gate and by measuring the induced current, to determine the solenoid position.
Multiplexers 214 and 215 are connected to each loop of each of the two axes of the gate, that is to say here to each of the vertical and horizontal loops, respectively. The outputs of the multiplexers 214 and 215 are connected to the Automatic Gain Controllers (AGC) 221 and 222, respectively, to a module 220 of the hardware module of the floor element 101.
The output signals of the automatic gain controllers 221 and 222 are first demodulated in the demodulators 223 and 224, respectively. Demodulation produces a continuous signal (DC, acronym for Direct Current in English terminology) proportional to the original sinusoid complemented by alternative components (AC, acronym for Alternating Current in English terminology) that are multiples of the fixed frequency emitted by the solenoid.
According to a scheme currently implemented, the calculation module, referenced here 230, of the hardware module of the ground element 101, drives the multiplexers 214 and 215 in order to activate sequentially the loops, that is to say the activate an n + 1 loop after a loop n. When the last loop is reached, the processor initiates a new cycle and controls the activation of the first loop.
A bandpass filter is advantageously implemented in each automatic gain controller 221 and 222 to suppress the unwanted harmonics of the signal as well as the electromagnetic background noise. This filtering makes it possible to refine the measurements of the signals coming from the multiplexers 214 and 215 which are demodulated in the demodulators 223 and 224 and then digitized in the analog / digital converters (CAN) 225 and 226, respectively.
The numerical values obtained are transmitted to the central processing unit (CPU) 230 of the calculation module for storage. As illustrated, the central processing unit 230 controls the demodulators 223 and 224.
After the values have been stored, the CPU increments the address of the multiplexers to digitize the signals from subsequent loops. When a last loop is reached, the central processing unit resets the address of the multiplexer corresponding to the value of the first loop of the axis considered. At the end of a cycle, the central processing unit has stored, for each axis, as many numerical values as there are adjacent loops close to the position of the solenoid. From these values, the central processing unit calculates the position of the solenoid by interpolation as described below.
It is observed here that the grounding of the loops can be ensured by metal strips positioned between the different loops in order to protect them from electromagnetic interference. An alternative is to have a uniform ground plane under the conductive grid.
Furthermore, the module 210 here comprises a radio transmitter 227, controlled by the central processing unit 230 of the calculation module, for activating a location module of a hybrid mobile element. By way of illustration, the central processing unit 230 transmits to the radio transmitter 227 an identifier of a location module to be activated. This identifier is coded and then transmitted as a digital or analog radio signal. Each location module receiving this signal can then compare the received identifier with its own identifier and activate if the identifiers are identical.
The module 220 further comprises communication means 228, for example similar to the radio transmitter 227. These communication means make it possible to communicate with the hybrid mobile elements in order to obtain displacement data from inertial units that are integral with the location modules. , particularly useful when the activated location module is out of the detection range of the module 210. These communication means also allow the central unit 230 to send to a given hybrid mobile element a previously calculated position information through the signal transmitted by the localization module that it integrates, or to send data for resetting the displacement data of the inertial unit. Alternatively, the communication means 228 may be merged with the element 227.
The modules 220 and 230 allow the real-time calculation of a hybrid position as described above.
Thus, to estimate the position of a location module assembly, it is necessary to perform a cycle on each location module and, for each of these cycles, according to the embodiment described here, a cycle on each set of location modules. loops.
A plurality of sensing surfaces may be combined with each other, the area of the resulting sensing surface being the sum of the areas of the combined sensing surfaces. For these purposes, a detection surface is considered as master, the others being considered as slaves. The sequential activation of the moving elements is managed by the master detection surface which preferably receives the positions calculated by the hardware modules associated with each slave detection surface and consolidates them by producing a table containing the coordinates and angles of freedom of the location modules.
Figure 3 is composed of Figures 3a and 3b.
Figure 3a schematically illustrates the physical principle of inductive coupling between a solenoid and a conductive loop of a detection surface.
Each hybrid mobile element whose position and / or orientation must be calculated comprises at least one solenoid whose axis is preferably oriented towards the detection surface.
The solenoid 300 is traversed by an alternating current and emits an electromagnetic field which propagates towards the detection surface, in particular, in this example, towards the loop 211. The loop 211, receiving an electromagnetic field coming from the solenoid 300, couples with solenoid 300. It is then possible to measure an alternating signal at the terminals of this loop, referenced 301.
The coupling between the solenoid 300 and the loop 211 can be expressed in the form of the following relation,
where E is the voltage across the solenoid 300, R is the voltage of the signal received at the terminals 301 of the receive loop 211, D is the distance between the solenoid 300 and the receive loop 211, and k is a constant related to intrinsic factors of the system including the solenoid and the receiving loop, including the number of turns of the solenoid and the size of the loop.
FIG. 3b schematically illustrates an interpolation mechanism making it possible to determine the position of a solenoid placed on a detection surface, along a given axis, from measurements obtained by a system such as that described with reference to FIG. 2. This mechanism can be implemented in step 403 (FIG. 4) for calculating the position of the hybrid mobile element from the signal (electromagnetic field) received from its location module.
It is assumed here that the solenoid is located near vertical loops B3, B4 and B5, positioned at abscissa X3, X4 and X5, the voltages measured at the terminals of these loops being denoted V3, V4 and V5, respectively. The solenoid is here at a position, on the abscissa, denoted XS.
The coordinates X3, X4 and X5 can be obtained by the central processing unit of the ground element (or interfacing device) from an identifier of the corresponding loop (these values are predefined according to the routing scheme of the detection surface and, preferably, stored in a non-volatile memory).
The curve portion 302 shown in FIG. 3b illustrates the voltage variation for the XS position of the solenoid according to the positions of the loops coupled with the solenoid, extrapolated from the values measured by the loops B3, B4 and B5. It can be assimilated to a function of the second degree of parabolic type. This local approximation corresponds, in practice, to the phenomenon of electromagnetic coupling between a solenoid and loops of a conductive grid.
The following relationships illustrate this property:
where a and b are constants, where a is a constant less than zero (a <0).
On the other hand, considering the hypothesis of a function of the second degree, the relations between abscissas X3, X4 and X5 can be expressed in the following form:
Where ΔΧ is the distance between abscissas X3 and X4 and between abscissa X4 and X5).
Thus, it is possible to interpolate the position of the solenoid according to the following formula:
It is also possible, according to the same logic, to determine the position of the solenoid along the ordinate axis.
In addition, the distance between the solenoid and the loop (ie the altitude of the solenoid relative to the detection surface) can be defined according to the following relation:
The distance D is therefore a function of the value R representing the voltage at the terminals of the considered loops of the detection surface. It can be extrapolated from the measurements made. It is noted that the accuracy of this distance calculation is particularly related to the stability of the signal E emitted by the solenoid whose value must be as constant as possible over time, which requires a stabilized power supply in the localization module which should not drop when discharging the battery. This can be provided by a voltage regulator of the location module.
FIGS. 4a and 4b are flowcharts showing steps implemented respectively by an interfacing device (FIG. 4a) and a hybrid moving element (FIG. 4b) according to a first embodiment of the invention.
FIGS. 4a and 4b illustrate a first example of an algorithm that can be used to calculate the positions and / or orientations of hybrid mobile elements.
In this first example, the hybrid calculation of the position in case of failure to receive an electromagnetic signal from the selected location module (that is to say in the absence of reception of an electromagnetic signal during the activation of the location module) is implemented in the interfacing device, for example by a central processing unit of the floor element 101 shown in FIG.
The steps implemented by the interfacing device according to this first embodiment are described here with reference to FIG. 4a.
During a first step 401, a location module integrated with a hybrid mobile element is selected and activated by the interfacing device.
In practice, the interfacing device selects a location module identifier from a plurality of identifiers. By way of illustration, the central processing unit 230 of the interfacing device transmits to the radio transmitter 227 of the interfacing device an identifier of a location module to be activated. This identifier is coded in order to be transmitted to all the location modules in the form of a digital or analog activation signal. Each location module receiving this signal can then compare the received identifier with its own identifier and activate if the identifiers are identical. This activation consists, for example, in feeding the solenoid 300 of the selected location module so that it emits an electromagnetic field.
During a step 402, a test is performed to know if a signal from the selected module is received.
In practice, when a location module is selected and activated as described above, it emits a signal, for example an electromagnetic field, to the attention of the interfacing device, in particular its detection surface 210.
However, when the locating module emits this electromagnetic field while it is outside the detection range of the detection surface 210 of the interfacing device, it can not detect the electromagnetic field emitted and therefore can not calculate the position from it. Step 402 is to detect such a situation.
When the electromagnetic field emitted by the activated location module is detected in step 402, this means that it is in the detection range of the detection surface 210 of the interfacing device.
Position information can then be calculated in step 403 from the received electromagnetic field, for example by interpolation as described with reference to FIG. 3b.
This position information is then stored in association with the date of its calculation in a memory of the interfacing device (step 404). As will be explained in more detail later, this position information and the associated date will be used to recalibrate displacement data from the inertial unit of the selected hybrid moving element, before or during the hybrid calculation of new position information at a time when calculation of the position information according to step 403 is not possible.
When no electromagnetic field is detected by the sensing surface 210 of the interfacing device during step 402, this means that the selected locator module is out of range of the sensing surface 210.
In this case, displacement data of an integral inertial unit of the selected location module are obtained (step 405). In practice, these displacement data are dated and are received via the communication means 228 (possibly coinciding with the HF transceiver 227) of the interfacing device. For example, these displacement data are obtained on request of the interfacing device. As a variant, the hybrid mobile element may regularly transmit interface device displacement data, for example every second or 100 times per second, depending on the targeted application (for example augmented or virtual reality).
As mentioned above, the displacement data of the locating module measured by the integral inertial unit of this locating module comprise for example: one (or more) speed (s) of rotation at a given instant provided by a gyro; one (or more) acceleration (s) at a given moment provided by an accelerometer; - one (or more) estimate (s) of the direction of the magnetic field at a given instant provided by a magnetometer.
This list is not exhaustive. These displacement data can be obtained by different sensors.
During an optional step 406, the displacement data obtained in step 405 are processed so as to correct a possible time drift or the effect of an impact on the inertial unit. This processing, called "resetting", is based on one or more positions calculated during step 403 from an electromagnetic signal emitted at a previous instant by the selected location module while it was within range of the detection surface 210. As mentioned above, such a position is stored with its calculation date (step 404). The knowledge of the date of the calculation and the value of the position at this precise moment makes it possible to recalibrate the data of the inertial unit, themselves dated. As an illustration, the interfacing device can follow, from successive calculations of the position of the same location module, the evolution over time of its position and thus identify the moments when this location module at a zero speed characterizing a contact without sliding. These particular moments (non-slip contact) make it possible to reset the positions calculated from the displacement data of the inertial unit, for example by resetting the estimated speed to zero.
It will be noted that a hybrid mobile element comprising two location modules already makes it possible to correct the drift of the displacement data of the inertial unit around the vertical axis of the hybrid mobile element.
During a step 407, the interfacing device performs a hybrid calculation of a new position information of the selected location module. This particular calculation is described as hybrid because it uses on the one hand the displacement data of the inertial unit obtained in step 405, optionally adjusted (if necessary) in step 406, and on the other hand one or more previously calculated position information (s) while the selected location module was in the detection range (ie in a step 403). Those skilled in the art understand that this hybrid calculation (step 407) takes into account the date of the displacement data and that of the prior position information previously stored in step 404.
Indeed, in order to allow the coherent hybrid computation, the displacement data received from the hybrid mobile element and the position information calculated by the interfacing device are synchronized.
To do this, the interfacing device can send a top at a regular rate, indicating when (in its local clock) corresponds this top. Thus, the hybrid mobile element is capable of determining the date of the data that it sends, in particular displacement data of the inertial unit, expressed in the local clock of the interfacing device.
Alternatively, it is possible to use a tops counter at the interfacing device and assign a top number to the received movement data.
According to another possibility, a clock synchronization protocol can be used, for example the NTP protocol (acronym for Network Time Protocol in English terminology) for synchronizing the clocks of the hybrid mobile element and the interfacing device.
Thus, the hybrid computation 407 makes it possible, in the absence of an electromagnetic field emitted by the solenoid of the selected location module, to determine instantaneous position information, based on old position information and displacement data. By way of illustration, suppose that the displacement data comprise the speed V (T1) of displacement of the location module. Then, the hybrid computation of the position P (T1) of the displacement module at time T1 can be carried out by applying the following formula: (71) = 7 (70) + V (71). (71 - 70) Where P (T1) is the position of the location module calculated at time T1, P (T0) is the position of the location module calculated at time T0 (prior to T1), V (T 1) is the speed of the location module at T1 time.
This example is not limiting and more complex calculations, for example comprising one or more integrations over time can be implemented.
In particular, such a hybrid calculation possibly comprising the abovementioned registration may, for example, be based on hybridization algorithms well known to those skilled in the art such as Kalman filters, extended Kalman filters or complementary filters.
Thus, the invention makes it possible to obtain, in real time, position information from an activated location module (step 403 or step 407), whether or not the hybrid mobile element is in the detection range of the detection surface. , this from two types of data: the displacement data of the inertial unit integral with the location module, and the electromagnetic signals emitted by the latter when it is in the detection range of the detection surface.
Advantageously, the combination of the inertial unit with the location module, constituting different systems with complementary characteristics, makes it possible to overcome the shortcomings of each of them. For example, calculating the position of the location module from electromagnetic signals that it emits (step 403) is accurate and does not suffer from a drift problem over time, but this calculation is subordinate to the detection range. limited detection area 210.
The inertial unit is another means of positioning based on different physical principles, namely inertia, whose measurements are autonomous and reliable. The problems of drift over time or the effect of shocks to the inertial unit can be solved by the use of old positions calculated during steps 403.
Correspondingly, and as shown in Fig. 4b, the hybrid mobile element receives an activation signal (step 408) sent by the interfacing device in step 401. By way of illustration, the radio receiver 602 of the hybrid mobile element shown in FIG. 6 receives an activation command comprising a location module identifier in coded form. The hybrid mobile element receiving this signal can then compare the received identifier with the identifier of its location module (s) and activate it if the identifiers are identical. This activation consists, for example, in feeding the solenoid 300 of the selected location module so that it emits an electromagnetic field.
During a step 409, the location module thus activated emits a signal, for example an electromagnetic field. However, even if such a signal is emitted, it is not necessarily received by the interfacing device. In particular, if the locating module is out of range of the detection surface 210, then the electromagnetic signal is emitted but is not perceived by the detection surface 210.
During a step 410, the hybrid mobile element transmits movement data of the inertial unit, which are received by the interfacing device during step 405.
In practice, as shown in FIG. 6, these displacement data are generated by the sensors of the inertial unit 607 and are retrieved (and dated) by the processing unit 609 of the hybrid mobile element in order to be sent via the communication means 608 (possibly confused with the transceiver 602). The date potentially assigned to the displacement data is intended to allow synchronization of the latter with the positions stored in the interfacing device in step 404. As mentioned above, this synchronization is allowed either by a dating of the displacement data. at the hybrid element level, in the interfacing device clock before sending (sending regular rate tops and corresponding dates in the interfacing device clock repository, using synchronization protocol of clocks for example NTP), or at the level of the interfacing device (tops counter).
This step 410 can be performed on request of the interfacing device or regularly, for example every second or 100 times per second, depending on the intended application (eg augmented or virtual reality).
FIGS. 4c and 4d are flowcharts showing steps implemented respectively by an interfacing device (FIG. 4c) and a hybrid moving element (FIG. 4d) according to a second embodiment of the invention.
FIGS. 4c and 4d illustrate a second example of an algorithm that can be used to calculate the positions and / or orientations of hybrid mobile elements.
In this second example, the hybrid calculation of the position in the event of a failure of reception of an electromagnetic signal from the selected location module (that is to say in the absence of reception of an electromagnetic signal during activation of the location module) is implemented in the hybrid mobile element selected and activated by interfacing device, for example by the processing unit 609 shown in FIG. 6 and responsible for processing data from the inertial unit or associated location module.
The steps implemented by the interfacing device according to this second embodiment are described here with reference to FIG. 4c.
During a first step 411, similar to step 401 of FIG. 4a, a location module integrated into a hybrid mobile element is selected and activated by the interfacing device.
During a step 412, similar to step 402 of FIG. 4a, a test is performed to know if a signal coming from the selected module is received.
In practice, when a location module is selected and activated as described above, it emits a signal, for example an electromagnetic field, to the attention of the interfacing device, in particular its detection surface 210.
However, when the locating module emits this electromagnetic field while it is outside the detection range of the detection surface 210 of the interfacing device, it can not detect the electromagnetic field emitted and therefore can not calculate the position from it. Step 412 is to detect such a situation.
When the electromagnetic field emitted by the activated location module is detected in step 412, this means that it is in the detection range of the detection surface 210 of the interfacing device.
Position information can then be calculated in step 413, similar to step 403 of FIG. 4a, from the received electromagnetic field, for example by interpolation as described with reference to FIG. 3b.
This position information is then stored in association with the date of its calculation in a memory of the interfacing device (step 414 similar to step 404 of FIG. 4a).
As will be explained in more detail later, this position information and the associated date will be used by the hybrid moving element to read off displacement data from the inertial unit, before or during the hybrid calculation of a new position information at a time when calculation of the position information by the interfacing device according to step 413 is not possible.
To do this, the interfacing device transmits registration data based on the position calculated in step 413 and stored with its date in step 414. According to a particular embodiment, these registration data directly comprise this position. as well as its date. According to another particular embodiment, the registration data may for example comprise an instruction for resetting the sensors of the inertial unit, so that the next displacement data measured by it will be representative of a displacement of the location module. with respect to its position as calculated in step 413. The registration data may alternatively include other information based on one or more positions calculated by the interfacing device, for example a one-off speed or acceleration given.
When no electromagnetic field is detected by the sensing surface 210 of the interfacing device in step 412, this means that the selected locator module is out of range of the sensing surface 210.
In this case, the interfacing device informs the hybrid mobile element comprising the corresponding location module, during a step 416. In practice, this information is sent via the communication means 228 (possibly coinciding with the HF transceiver 227) controlled by the processing unit 230 of the interfacing device.
This information can be directly the last position calculated by the interfacing device from an electromagnetic signal. Note that in certain embodiments in which the registration data sent to step 415 directly include the position or allow to deduce this position, the hybrid mobile element is already in possession of this information of position. Thus, the information sent at step 416 may simply consist of a trigger instruction of the hybrid computation.
During a step 417, the interfacing device receives the position of the hybrid mobile element, which, in this embodiment, is calculated by the hybrid mobile element, as will be described in more detail with reference to FIG. 4d which represents the steps implemented at the level of the hybrid mobile element in this second embodiment.
Thus, the invention makes it possible to obtain, in real time, position information from an activated location module (step 413 or step 417), whether or not the hybrid mobile element is in the detection range of the detection surface. , this from two types of data: the displacement data of the inertial unit integral with the location module, and the electromagnetic signals emitted by the latter when it is in the detection range of the detection surface.
Correspondingly, and as shown in Fig. 4d, the hybrid mobile element receives an activation signal (step 418 similar to step 408 of Fig. 4b) sent by the interfacing device at step 411.
During a step 419, similar to step 409 of FIG. 4b, the location module thus activated emits a signal, for example an electromagnetic field. It is recalled that even if such a signal is emitted, it is not necessarily received by the interfacing device. In particular, if the locating module is out of range of the detection surface 210, then the electromagnetic signal is emitted but is not perceived by the detection surface 210.
During a step 420, a test is performed to know if information from the interfacing device is received, indicating that it has not received the expected electromagnetic signal. As explained above, this situation occurs when the location module transmitting this signal in step 419 is located out of range of the detection surface 210.
When no information of this type is received after a predetermined time, for example equal to the duration between two clock ticks of the hybrid mobile element, it means that the electromagnetic signal emitted by the localization module to the step 419 has been received (it is then located in the range of the detection surface 210) by the interfacing device and a position information can be calculated by it from this signal ( step 413 of Figure 4c).
During a step 421, the hybrid mobile element receives reset data sent by the interfacing device (step 415 of Figure 4c). As a reminder, these registration data are calculated by the interfacing device from the position calculated by the electromagnetic signal received from the activated location module.
When, on the other hand, the hybrid mobile element receives information indicating that no signal has been received from the activated location module, it means that the electromagnetic signal emitted by the location module at step 419 does not occur. has not reached the detection surface 210 and the location module is located out of range of the detection surface 210.
In this case, the hybrid mobile element retrieves the displacement data of the inertial unit and their date (step 422), for example in a memory associated therewith. In practice, as shown in FIG. 6, it is the processing unit 609 that obtains the displacement data of the inertial unit 607.
In a step 423, similar to step 406 of FIG. 4a except that it is based on the reset data received at 421, the displacement data obtained at step 422 is processed by the hybrid moving element so as to correct a possible temporal drift or the effect of a shock suffered by the inertial unit.
This resetting processing is based on one or more positions calculated by the interfacing device from an electromagnetic signal emitted at a previous instant by the selected location module while it was within the range of the detection surface 210 As previously mentioned, such a position is typically received as a registration data with the associated date. According to an alternative embodiment, a position calculated by the interfacing device can be received as information at 420. Knowledge of the date of calculation of the position received and the value of the position at this precise moment makes it possible to to recal the data of the inertial unit, themselves dated, as explained with reference to step 406 of Figure 4a.
During a step 424, similar to step 407 of FIG. 4a, the hybrid mobile element performs a hybrid calculation of new position information of the selected location module. It is recalled that this particular calculation is described as hybrid because it uses on the one hand the displacement data of the inertial unit recaled in step 423, and on the other hand one or more information position (s) previously calculated (s) (eg received as reset data in step 421) by the interfacing device while the selected location module was in the detection range (ie in a step 413 of Figure 4c). Details on the hybrid calculation have been given previously with reference to step 407 of Fig. 4a (first embodiment), they will not be repeated here.
It is recalled however that such a hybrid calculation (as well as the registration) can for example be based on hybridization algorithms well known to those skilled in the art such as Kalman filters, extended Kalman or complementary filters.
Thus, in this second embodiment also, the hybrid computation 424 makes it possible, in the absence of an electromagnetic field emitted by the selected location module, to determine an instantaneous position information, based on an old position information. and displacement data.
Finally, the hybrid mobile element transmits the position thus calculated to the interfacing device during a step 425. Thus, the interfacing device obtains position information although it could not calculate it itself. even in the absence of detection of the electromagnetic field emitted by location module.
FIGS. 5a and 5b schematically illustrate two examples of hybrid mobile elements whose position can be determined and whose position and orientation can be determined, respectively, according to particular embodiments of the invention. The hybrid mobile element 500 shown in FIG. 5a comprises a single locator module 501. As illustrated, the locator module comprises a solenoid. The radial axis of the solenoid is advantageously perpendicular to the plane of the ground element so that the electromagnetic radiation of the solenoid propagates optimally towards this surface.
This hybrid mobile element 500 further comprises an inertial unit 502 integral with the locator module 401, as well as communication means 503 for sending data relating to the displacement of the inertial unit 502.
The three-dimensional position of the hybrid moving element 500, comprising a single solenoid, can be calculated in accordance with the invention as previously described. Indeed, from the displacement data of the integral inertial unit 502 and / or from the signal emitted by the solenoid of the locating module 501, it is possible to calculate the hybrid position at any time. When several moving elements are present on the detection surface 210, the position of each hybrid mobile element is determined sequentially. The hybrid mobile element 500 'shown in FIG. 5b comprises two independent location modules 501-1 and 501-2. Again, as illustrated, the radial axis of the solenoids is preferably perpendicular to the plane of the sensing surface so that the electromagnetic radiation of the solenoid propagates optimally to that surface.
This hybrid mobile element 500 'furthermore comprises an inertial unit 502' integral with locating modules 501-1 and 501-2, as well as communication means 503 'for sending data relating to the displacement of the inertial unit 502'.
Each solenoid 501-1 and 501-2 of the hybrid movable element 500 'can be activated independently of one another sequentially. Thus, it is possible to determine the position of the hybrid movable member 500 'by determining the position of each solenoid of the locator modules 501-1 and 501-2 and knowing their position in the hybrid movable member 500'. Likewise, it is possible to know the orientation of this hybrid mobile element from the relative positions of the solenoids of the locating modules 501-1 and 501-2 and their position in the hybrid mobile element 500 '. It should be observed here that the use of the coordinates of the solenoids of the locating modules 501-1 and 501-2, in the plane of the detection surface, makes it possible to determine the orientation of the hybrid mobile element 500 'in this plan while the use of the altitude of the solenoids of the locating modules 501-1 and 501-2 makes it possible to calculate the pitch of the hybrid mobile element 500 '.
The three-dimensional position and the orientation of the hybrid moving element 500 ', comprising two solenoids, can be calculated in accordance with the invention as previously described. In fact, from the displacement data of the inertial unit 502 'and / or from the signals emitted sequentially by the solenoids of the location modules 501-1 and 501-2, it is possible to calculate the hybrid position at any moment . When several moving elements are present on the detection surface 210, the position of each hybrid mobile element is determined sequentially.
It is noted here that hybrid mobile elements comprising a single solenoid and comprising two solenoids may be used together on a detection surface provided that the intelligence thereof is capable of activating each solenoid independently of the others.
The capture of the orientation of hybrid mobile elements can thus be obtained by providing each hybrid mobile element with at least two location modules (not to be aligned along a perpendicular to the detection surface) and defining a rule of thumb. identification of these location modules. The sequential activation of location modules, by the ground element, makes it possible to estimate the position and / or the orientation of a plurality of hybrid mobile elements provided with these location modules.
When a location module receives an activation command dedicated to it, it triggers an electromagnetic emission. The detection system, knowing the identification of the location module being transmitted, can then link the calculated position information to the identifier of the location module.
It is thus possible to construct an array containing, for each hybrid mobile element, an identifier, an abscissa, an ordinate and, preferably, an altitude in a reference of the detection surface. The sequential activation of the electromagnetic emission of the location modules allows the use of a single transmission frequency for all the hybrid mobile elements managed by the system.
FIG. 6 schematically illustrates logic blocks of a hybrid mobile element whose position can be determined from an interfacing device (or floor element) as illustrated in FIG. 2.
Such a hybrid mobile element is preferably autonomous as regards both its power supply and the reception of electromagnetic emission control signals.
In this example, consider a hybrid mobile element comprising a single location module, as in Figure 5a. Those skilled in the art will be able without difficulty to adapt the present teaching to a hybrid mobile element comprising two or more locating modules (as shown in FIG. 5b). The hybrid mobile element thus comprises a power supply module 601 supplying a voltage for all the components of the location module as well as a reception and control detection module 602 which receives and demodulates a signal, for example a signal HF, emitted by an external module of the ground element, to determine whether the signal received aims to activate this location module. As described above, such detection can be performed by comparing a received identifier with a previously stored identifier. The hybrid mobile element 600 further comprises a switch 603, controlled by the reception and control detection module 602, as well as a selective amplifier 604 controlled by the switch 603. Finally, the hybrid mobile element 600 comprises a local oscillator 605 generating a frequency, preferably fixed, stable and square type and a solenoid 606. The hybrid mobile element 600 also comprises an inertial unit 607 and communication means 608 with the communication means 228 of the floor element 101. Alternatively, the communication means 608 could be attached to or confused with the HF receiver 602 and communicate with the HF transmitter 227 of the floor element. The hybrid mobile element comprises a processing unit 609 configured to recover the raw displacement data of the inertial unit 607, store them in a memory of the hybrid mobile element (not shown) and to control their sending via the communication means 608.
In some embodiments, such as that described with reference to Figures 4c and 4d, the processing unit 609 is configured to implement hybrid position information calculations as previously described.
In a variant, the inertial unit 607 can integrate such an intelligence, that is to say integrate the processing unit 609. The selective amplifier 604 generates, according to the position of the switch 603 and from the signal coming from the local oscillator 605, a sinusoidal voltage across the solenoid 606, allowing the solenoid 606 to generate some radiation power.
Several types of power supply 601 can be used. Power can be obtained from a rechargeable battery and a standard control circuit. It can also be obtained from a battery and a voltage regulator to obtain a constant voltage throughout a range of use of the battery. This solution is particularly advantageous when the system must calculate the altitude of hybrid mobile elements implemented. The power supply can also be provided indirectly, by remote power coupled with the use of energy storage means.
According to this embodiment, a layer of dedicated radiating solenoids is placed under the detection surface. These solenoids are traversed by a sinusoidal signal and the power emitted by each solenoid is sufficient to remotely power the positioning modules positioned above it. The locator modules are also equipped with a solenoid for receiving, by induction, the signal emitted by the solenoids present under the detection surface. Other remote power supply means may be used, for example antennas using Powercast technology (Powercast is a brand).
The energy storage means comprise for example a capacitor of high capacity which is loaded from the solenoid of the location module. The capacitor is used as a voltage source to power the other modules.
Alternatively, the energy storage means comprise a battery present in the hybrid mobile element, for example a lithium battery. The solenoid of the localization module then constantly recharges this battery as soon as it is traversed by an induced current. A charge / discharge protection circuit is advantageously associated with the battery so that it remains within its acceptable voltage range. If the moving element altitude is to be evaluated, the voltage source is preferably regulated so that the supply voltage is constant during a period of use of this voltage source, i.e. during an estimation of position and / or orientation of the hybrid moving element.
Mobile hybrid elements located on a sensing surface and used together may use different power types.
Moreover, when a hybrid mobile element comprises more than one location module, certain components, in particular the power supply, may be common to some or all of the location modules.
FIG. 7 illustrates an exemplary application in which hybrid mobile elements according to the invention can be advantageously used.
In an environment 700, the user is equipped with an augmented reality system or virtual reality comprising a helmet 701, for example HMD type (acronym for Head-Mounted Display in English terminology).
This system comprises for example an inertial unit 702 secured to the helmet 701 and incorporating for example one or more magnetometers, accelerometers, gyrometers. Thus, the displacement data from the inertial unit 702 make it possible to describe the displacement of the helmet 701 according to several degrees of freedom, for example six degrees of freedom.
In this example, the user is equipped at each foot with a hybrid mobile element 703 and 704 as described above and moves on a floor element 705 similar to the floor element 101 described above. It is recalled here that the invention is however not limited to a localized interfacing device on the ground, but it also covers cases where the interfacing device is disposed on side walls or on the ceiling.
Thus, by applying the methods described above, it is possible to follow the position of the two feet of the user in the reference of the floor element 705.
Advantageously, the position data thus obtained make it possible to reset the inertial unit 702 located at the level of the helmet 701.
For example, assuming the user moves so that the distance D between the helmet 701 and the ground member 705 is constant, then the inertial unit 702 can be recalibrated using the calculated position information. at the feet of the user, the component in the direction perpendicular to the plane of the floor element being translated from the distance D.
Alternatively, it is possible to place an altitude measuring means (barometer or range finder) at the level of the helmet 701. This makes it possible to readjust the data of the inertial unit 702, even if the altitude (distance D) varies in the weather.
The registration of the inertial unit 702 can also be done more precisely if one implements a model of inverse kinematics linked to the human body.
It is recalled that the inverse kinematics allows for example, for a human model, to determine the torsion of the vertebral column, ankles, knees, neck, or any other articulation of the human body, from the trajectories or the positions hands or feet. Rather than manually specifying a set of joint coordinates, a model of inverse kinematics makes it possible to formulate a movement of the skeleton from its significant components, for example the respective trajectory of the hands or feet, the orientation of the pelvis.
When a model of inverse kinematics is used, the knowledge of the position data of the feet by the hybrid mobile elements 703 and 704 as well as the data coming from the inertial unit 702 makes it possible to calculate the position of the different parts that make up the human body. (legs, spine, neck, head). This gives a more precise position of the element 702 with respect to the elements 703 and 704 thanks to this model of inverse kinematics.
Figures 8 and 9 illustrate alternative embodiments of Figure 7, according to which it is possible to calculate more precisely the position of the different parts of the human body of the user. Of course, the invention can also advantageously apply to the precise location of the different members of a robot or any other complex object, for example hinged.
In the examples shown in Figures 8 and 9, the user moves in an environment 800 (Figure 8), respectively 900 (Figure 9). It is equipped with an augmented reality or virtual reality system comprising a helmet 801 (FIG. 8), respectively 901 (FIG. 9), similar to 701 (FIG. 7).
This is for example a helmet HMD type (acronym of Head-Mounted Display in English terminology).
Also, the system comprises an inertial unit 802 (FIG. 8), respectively 902 (FIG. 9), similar to 702 (FIG. 7), integral with the helmet 801, respectively 901. The inertial unit integrates, for example, one or more magnetometers, accelerometers, gyros.
Thus, the displacement data from the inertial unit 802, 902 respectively make it possible to describe the displacement of the helmet 801, respectively 901 according to several degrees of freedom, for example six degrees of freedom. The user is furthermore equipped on each leg with a hybrid mobile element 803 and 804 (FIG. 8), respectively 903 and 904 (FIG. 9) similar to 703 and 704 (FIG. 7), and moves on a floor element 805. (Figure 8), respectively 905 (Figure 9), similar to 705 (Figure 7).
In the example of FIG. 8, the user is additionally equipped at the belt with another inertial unit 808, and on the helmet 801 with a means 809 for measuring the altitude of the helmet 801, for example a rangefinder or a barometer.
An upward looking telemeter for example allows to measure the distance of the user's head from the ceiling and finally to calculate the altitude of the user's head by the knowledge of the distance between ground and ceiling. A barometer is used to measure the altitude from the air pressure.
Advantageously, by applying the methods described above, it is possible to follow the position of the two feet of the user equipped with the hybrid mobile elements 803, 804, in the reference of the floor element 805.
The knowledge of the altitude of the user's head by the means 809 makes it possible to know the position of the helmet even if the distance D between the helmet 801 and the ground element 805 varies in real time, which happens for example when the user bends or jumps with respect to the surface element 805.
Data from the inertial unit 802 can be readjusted using the position information calculated at the feet of the user, the component in the direction perpendicular to the plane of the ground element being translated from the distance D which dynamically varies.
The registration of the inertial unit 802 can also be done more precisely if one implements a model of inverse kinematics linked to the human body. In this case, the knowledge of the position data of the feet by the hybrid moving elements 803 and 804 as well as the data coming from the inertial unit 802 makes it possible to calculate the position of the different parts that make up the human body Gambes, vertebral column, neck, head), it being understood that the different elements 801 to 804, 808 and 809 are capable of communicating together.
Thus, the inertial unit 808 makes it possible to obtain an even more precise inverse kinematics model, since it makes it possible to obtain position data of the middle of the body and thus increases the precision of the inverse kinematic model.
In the example of FIG. 9, the user is equipped with a magnetic system (constant or pulsed magnetic fields) consisting of a magnetic transmitter 908 emitting a magnetic field in a plurality of directions (preferably in three perpendicular directions) and A plurality of magnetic receivers (sensors) 909, 910 and 911. For example, such a system is known as Polhemus Fastrak (Polhemus Fastrak is a trademark) and Razer Hydra (Razer Hydra is a trademark). The transmitter comprises for example three solenoids each emitting a magnetic field in orthogonal directions.
As shown in Figure 9, the transmitter 908 is for example located at the waist of the user. The receiver 909 is located at the head of the user, for example on the headset 901. The receivers 910 and 911 (which are for example joysticks) are located in the hands of the user. In principle, the magnetic system (consisting of elements 908 to 911) makes it possible to obtain the coordinates of each receiver 909, 910 and 911, in the reference of the transmitter 908, this in a reliable and deterministic manner.
The different elements 901 (helmet), 903 (hybrid mobile element), 904 (hybrid mobile element) and 908 (magnetic transmitter) communicate together.
The position of the transmitter 908 relative to the feet equipped with the hybrid moving elements 903 and 904 can be obtained by assuming that the distance D between the transmitter 908 and the floor element 905 is constant. Thus the component of the position of the transmitter 908 in the direction perpendicular to the plane of the floor element 905 can be obtained by a simple translation of the distance D.
Alternatively, it is possible to place a rangefinder or barometer (similar to 809 in Figure 8) at the transmitter 908, to measure a dynamic altitude, that is, a variable distance D between the transmitter 908 and the floor element 905. This is particularly advantageous for cases where the user jumps or lowers with respect to the floor element 905.
Thus, methods according to the invention make it possible to calculate the position of the transmitter 908 in the reference of the floor element 905.
In addition, it is possible to know the respective positions of the receivers 909, 910 and 911 in this same frame, by receiving the coordinates of the receivers in the reference of the transmitter 908.
Advantageously, thanks to the use of the magnetic system described, the positions of the hands of the user (receivers 910 and 911) can be known in real time and the knowledge of the position of the head (receiver 909) can be readjusted with a very good accuracy the data of the inertial unit 902 in the reference of the floor element 905, for example as described above with reference to step 406 of Figure 4a.
Of course, the registration of the inertial unit 902 can also be done more precisely if a model of inverse kinematics linked to the human body is implemented. In this case, the knowledge of the position data of the feet by the hybrid mobile elements 903 and 904 as well as the data coming from the inertial unit 902 and the position of the receiver 909 in the reference of the floor element 905 make it possible to calculate the position of the different parts that make up the human body (legs, spine, neck, head).
Thus, in the examples of FIGS. 8 and 9, the knowledge of the position data of the feet by the hybrid mobile elements (803 and 804 in FIG. 8, 903 and 904 in FIG. 9) as well as the data coming from the inertial units ( 802 and 808 in Figure 8, 902 in Figure 9) and the magnetic system (Figure 9), can reliably calculate the position of different parts of the human body (legs, spine, neck, head). This gives a more precise position of the helmet (801, 901) and other equipment relative to the hybrid mobile elements 803, 804, respectively 903, 904.
Naturally, to meet specific needs, a person skilled in the field of the invention may apply modifications in the foregoing description.

权利要求:
Claims (20)
[1" id="c-fr-0001]
A hybrid mobile element (104, 105, 500, 600) for a device for interfacing a plurality of mobile elements with a computer system, said hybrid mobile element comprising at least one locator module (501) comprising the following means: (606) for transmitting an electromagnetic signal for calculating the position of said locator module; and, means (602) for receiving an activation signal and, according to at least one information of said activation signal, activating said means for transmitting an electromagnetic signal; said hybrid mobile element (104, 105, 500, 600) being characterized in that it further comprises: - an inertial unit (502, 607) integral with said locating module; and - communication means (503, 608) with said device for transmitting data relating to a displacement of the inertial unit.
[2" id="c-fr-0002]
The hybrid mobile element (104, 105, 500, 600) according to claim 1, wherein the communication means (503, 608) is further configured to receive at least one position information of said locator module (501).
[3" id="c-fr-0003]
The hybrid mobile element (104, 105, 500, 600) according to claim 2, further comprising hybrid calculating means (609) for new position information of said locator module (501), from the received position information and displacement data of the inertial unit.
[4" id="c-fr-0004]
The hybrid mobile element (104, 105, 500, 600) according to claim 3, wherein the communication means (503, 608) is further configured to transmit said new position information of said location module.
[5" id="c-fr-0005]
The hybrid mobile element (104, 105, 500, 600) according to one of claims 1 to 4, wherein said communication means (503, 608) is configured to receive data of resetting the displacement data of the plant. inertial (502), said resetting data being based on position information calculated from an electromagnetic signal emitted by said locator module.
[6" id="c-fr-0006]
The hybrid mobile element (104, 105, 500, 600) according to any one of claims 1 to 4, wherein the hybrid mobile element is configured to reset the displacement data of the inertial unit with each activation of said module. location (501).
[7" id="c-fr-0007]
7. hybrid mobile element (104, 105, 500, 600) according to any one of claims 1 to 6, further comprising remotely powered means for electrically powering components of said locator module.
[8" id="c-fr-0008]
8. hybrid mobile element (104, 105, 500, 600) according to any one of claims 1 to 7, further comprising energy storage means.
[9" id="c-fr-0009]
A device (101) for interfacing a plurality of hybrid mobile elements (104, 105, 500, 600) with a computer system, the device comprising a detection surface (210) and characterized by comprising the means following: - means (227) for sequentially activating at least one location module integrated with each hybrid mobile element of said plurality of hybrid mobile elements, a single location module can be activated at a given time; means (212, 213) for receiving at least one electromagnetic signal from said at least one activated location module; means (220, 230) for calculating in real time, from said at least one received electromagnetic signal, at least one position information, in a reference frame associated with said detection surface, of a hybrid mobile element comprising said module of activated location; communication means (228) for receiving data relating to a displacement of an inertial unit integral with said at least one activated location module in the absence of reception of an electromagnetic signal upon activation of said at least one module location; means (230) for real-time hybrid computation, from the received displacement data and the calculated position information, of new position information of said at least one activated location module.
[10" id="c-fr-0010]
The device (101) according to claim 9, wherein the communication means (228) is further configured to: - transmit the position information calculated from the received electromagnetic signal to the hybrid mobile element; and - to receive said new position information, calculated by the hybrid moving element from the transmitted position information.
[11" id="c-fr-0011]
Apparatus (101) according to claim 9 or 10, wherein the communication means (228) is further configured to transmit data for resetting the displacement data of the inertial unit, said resetting data being based on information calculated from an electromagnetic signal received.
[12" id="c-fr-0012]
A device (101) comprising a plurality of devices according to any one of claims 9 to 11, a device of said plurality of devices controlling at least some of the means implemented in the other devices of said plurality of devices.
[13" id="c-fr-0013]
13. A method for interfacing a plurality of hybrid mobile elements (104, 105, 500, 600) with a computer system, the method being characterized in that it comprises the following steps: - obtaining (403) at least one position information of a hybrid mobile element of said plurality, said hybrid mobile element comprising at least one activated location module, the at least one position information being calculated from at least one electromagnetic signal emitted by said at least one an activated localization module integrated in the hybrid mobile element, a single location module that can be activated at a given instant; then, in the absence of subsequent reception of an electromagnetic signal during the activation of said at least one location module: - obtaining (405, 422) data relating to a displacement of an inertial unit integral with said at least one activated location module; and - hybrid computing (407, 424) in real time, from the displacement data obtained and the position information obtained, a new position information of said at least one activated location module.
[14" id="c-fr-0014]
The method of claim 13, further comprising a step of resetting (406, 423) the displacement data of the inertial unit.
[15" id="c-fr-0015]
The method of claim 14, further comprising a step of storing (404) said position information obtained with the date of its calculation, said resetting step (406) being implemented from said stored position information .
[16" id="c-fr-0016]
The method of claim 14, further comprising a step of receiving (420) information indicative of a failure to receive an electromagnetic signal from said at least one activated locator module.
[17" id="c-fr-0017]
The method of claim 16, further comprising a step of receiving (421) registration data, said resetting step (423) being implemented from the received registration data.
[18" id="c-fr-0018]
The method of claim 17, further comprising a step of transmitting (425) the new calculated position information.
[19" id="c-fr-0019]
19. An assembly for virtual or augmented reality system, intended to equip a user in motion, said system comprising: at least one hybrid mobile element according to any one of claims 1 to 8, adapted to be worn by the user; at least one interfacing device according to any one of claims 9 to 12; a virtual or augmented reality headset adapted to be worn by the user, said headset being connected to said hybrid mobile element or to said interfacing device so as to enable the position of the headset to be tracked as a function of the relative position of the headset; the hybrid mobile element and helmet and the position of the hybrid mobile element.
[20" id="c-fr-0020]
20. An assembly according to claim 19, further comprising a magnetic positioning system comprising means for transmitting a magnetic field in a plurality of directions and a plurality of means for receiving said magnetic field emitted by the transmitting means, said magnetic positioning system being configured to determine the position of at least one of the receiving means in a coordinate system centered on the transmitting means, from the magnetic field received by said receiving means.

类似技术:

---

公开号 | 公开日 | 专利标题

---

EP3185110B1|2020-09-02|Hybrid mobile element, method and device for interfacing a plurality of hybrid mobile elements with a computer system, and assembly for virtual or augmented reality system

---

US11057751B1|2021-07-06|User identification system using directional antennas and cameras

---

US10414494B2|2019-09-17|Systems and methods for reliable relative navigation and autonomous following between unmanned aerial vehicle and a target object

---

EP1984696B1|2009-07-08|Motion capture device and associated method

---

US20140293266A1|2014-10-02|Local Alignment and Positioning Device and Method

---

CN107850901A|2018-03-27|Merged using the sensor of inertial sensor and imaging sensor

---

EP3227705B1|2021-11-24|Electronic device for the near locating of a terrestrial object, and method of locating such an object

---

FR2886501A1|2006-12-01|METHOD AND DEVICE FOR LOCALIZING A TERMINAL IN A WIRELESS LOCAL NETWORK

---

WO2015091402A1|2015-06-25|Method of determining the orientation of a sensor reference frame tied to a mobile terminal furnished with a sensor assembly, carried or worn by a user and comprising at least one motion tied motion sensor

---

WO2015058986A1|2015-04-30|Method for indoor and outdoor positioning and portable device implementing such a method

---

WO2017060660A1|2017-04-13|Method for estimating the movement of a pedestrian

---

US10515337B1|2019-12-24|User identification system

---

CN106662649B|2021-01-12|Dynamic tracking system and automatic guiding method based on 3D time-of-flight camera

---

JP2019517662A|2019-06-24|Accelerometer

---

EP1788357A1|2007-05-23|System for locating pedestrian user

---

EP2932182B1|2021-04-14|Method for accurately geolocating an image sensor installed on board an aircraft

---

FR3051952B1|2019-06-14|METHOD AND DEVICE FOR LOCATING OBJECTS OR MOBILE PERSONS

---

JP7014243B2|2022-02-01|Equipment, methods and programs

---

JP2022044671A|2022-03-17|Equipment, methods and programs

---

EP3109668A1|2016-12-28|Handheld apparatus for a visually impaired user

---

Cai2016|Towards Autonomous Unmanned Vehicle Systems

---

Yingcai2018|Multi-Sensor State Estimation for Micro Aerial Vehicles in Complex Environments

---

Rahnavard et al.2006|RoboCupRescue 2006-Robot League Team Ariana |

---

FR3054324A1|2018-01-26|GUIDING SYSTEM FOR GUIDING AN AIRCRAFT ALONG AT LEAST ONE AIR ROAD PORTION

---

Ahmed2013|Navigation: a novel approach for indoor localization with improved accuracy

同族专利:

---

公开号 | 公开日

---

US20170184387A1|2017-06-29|

---

FR3046261B1|2018-08-31|

---

US10527400B2|2020-01-07|

---

EP3185110B1|2020-09-02|

---

JP2017151087A|2017-08-31|

---

JP6985007B2|2021-12-22|

---

KR20170076608A|2017-07-04|

---

EP3185110A1|2017-06-28|

---

CN106918800A|2017-07-04|

引用文献:

---

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

GB2428802A|2005-07-30|2007-02-07|Peter Mccarthy|Wearable motion sensor device with RFID tag|

---

WO2012028827A1|2010-09-03|2012-03-08|Epawn|Method and devices for interfacing in real time a plurality of mobile elements with a computing system|

---

FR1057014A|1952-03-07|1954-03-04|Friedmann Kg Alex|Hot air heating installation|

---

US20090054077A1|2007-08-23|2009-02-26|Telefonaktiebolaget Lm Ericsson |Method and apparatus for sending data relating to a target to a mobile device|

---

US8675018B2|2007-09-05|2014-03-18|Microsoft Corporation|Electromechanical surface of rotational elements for motion compensation of a moving object|

---

CN102645222B|2012-04-10|2015-07-22|惠州市德赛西威汽车电子有限公司|Satellite inertial navigation method|

---

CN103399337B|2013-07-04|2015-08-19|Tcl通讯（宁波）有限公司|A kind of have mobile terminal and the method that GPS locates calibration function|

---

CN104703130B|2014-12-11|2018-08-24|上海智向信息科技有限公司|Localization method based on indoor positioning and its device|

---

CN105091882B|2015-06-30|2018-04-24|小米科技有限责任公司|Air navigation aid and device|

---

CN105093249A|2015-08-12|2015-11-25|浙大正呈科技有限公司|Inertial navigation device|US10838207B2|2015-03-05|2020-11-17|Magic Leap, Inc.|Systems and methods for augmented reality|

---

US10180734B2|2015-03-05|2019-01-15|Magic Leap, Inc.|Systems and methods for augmented reality|

---

EP3384468A4|2015-12-04|2019-01-30|Magic Leap, Inc.|Relocalization systems and methods|

---

US20170262049A1|2016-03-11|2017-09-14|Empire Technology Development Llc|Virtual reality display based on orientation offset|

---

AU2017305227B2|2016-08-02|2021-12-16|Magic Leap, Inc.|Fixed-distance virtual and augmented reality systems and methods|

---

US10812936B2|2017-01-23|2020-10-20|Magic Leap, Inc.|Localization determination for mixed reality systems|

---

CA3054617A1|2017-03-17|2018-09-20|Magic Leap, Inc.|Mixed reality system with multi-source virtual content compositing and method of generating virtual content using same|

---

US10769752B2|2017-03-17|2020-09-08|Magic Leap, Inc.|Mixed reality system with virtual content warping and method of generating virtual content using same|

---

EP3596705A1|2017-03-17|2020-01-22|Magic Leap, Inc.|Mixed reality system with color virtual content warping and method of generating virtual content using same|

---

US10477355B1|2017-12-13|2019-11-12|Amazon Technologies, Inc.|System for locating users|

---

EP3514566A1|2018-01-19|2019-07-24|Centre National d'Etudes Spatiales|Indoor positioning surface waveguide|

---

EP3514564A1|2018-01-19|2019-07-24|Centre National D'etudes Spatiales|Indoor positioning system|

法律状态:
2016-11-18| PLFP| Fee payment|Year of fee payment: 2 |

---

2017-06-30| PLSC| Publication of the preliminary search report|Effective date: 20170630 |

---

2017-10-20| PLFP| Fee payment|Year of fee payment: 3 |

---

2017-12-29| CA| Change of address|Effective date: 20171127 |

---

2017-12-29| CD| Change of name or company name|Owner name: STARBREEZE PARIS, FR Effective date: 20171127 |

---

2018-10-22| PLFP| Fee payment|Year of fee payment: 4 |

---

2019-12-20| PLFP| Fee payment|Year of fee payment: 5 |

---

2020-12-07| PLFP| Fee payment|Year of fee payment: 6 |

---

2021-11-04| PLFP| Fee payment|Year of fee payment: 7 |

优先权:

---

申请号 | 申请日 | 专利标题

---

FR1563352|2015-12-24|

---

FR1563352A|FR3046261B1|2015-12-24|2015-12-24|HYBRID MOBILE ELEMENT, METHOD AND DEVICE FOR INTERFACING A PLURALITY OF HYBRID MOBILE ELEMENTS WITH A COMPUTER SYSTEM, AND ASSEMBLY FOR A VIRTUAL OR INCREASED REALITY SYSTEM|FR1563352A| FR3046261B1|2015-12-24|2015-12-24|HYBRID MOBILE ELEMENT, METHOD AND DEVICE FOR INTERFACING A PLURALITY OF HYBRID MOBILE ELEMENTS WITH A COMPUTER SYSTEM, AND ASSEMBLY FOR A VIRTUAL OR INCREASED REALITY SYSTEM|

---

JP2016247514A| JP6985007B2|2015-12-24|2016-12-21|Hybrid mobile elements, methods and devices for interfacing multiple hybrid mobile elements with information processing systems, and assemblies for virtual reality or augmented reality systems.|

---

EP16205902.6A| EP3185110B1|2015-12-24|2016-12-21|Hybrid mobile element, method and device for interfacing a plurality of hybrid mobile elements with a computer system, and assembly for virtual or augmented reality system|

---

US15/388,592| US10527400B2|2015-12-24|2016-12-22|Hybrid mobile entity, method and device for interfacing a plurality of hybrid mobile entities with a computer system, and a set for a virtual or augmented reality system|

---

CN201611273015.0A| CN106918800A|2015-12-24|2016-12-23|Mixing moving element, interface connecting method and device and the sub-assembly for system|

---

KR1020160178374A| KR20170076608A|2015-12-24|2016-12-23|Hybrid mobile element, method and device for interfacing a plurality of hybrid mobile elements with a computer system, and assembly for virtual or augmented reality system|