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    • 专利摘要:
    A height adjustment system of an agricultural implement (O), comprising an arm (1) operable to raise and lower the agricultural implement, a measurement sensor of height, and a computer configured to provide an instruction for controlling the height of the arm from the measurements made by the height measuring sensor, characterized in that the height measuring sensor is an imaging system (2) comprising at least one camera mounted so as to be able to image a scene located in front of the agricultural tool in a travel direction of a vehicle equipped with the arm, and a computer processing unit configured to produce, from the delivered images by the at least one camera, a 3D reconstruction representative of the relief of the pictorial scene.
    公开号:FR3029389A1
    申请号:FR1462003
    申请日:2014-12-05
    公开日:2016-06-10
    发明作者:Nolwenn Briquet-Kerestedjian；Frederic Colledani；Baptiste Lelong；Patrick Sayd
    申请人:Commissariat a lEnergie Atomique CEA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    [0001] BACKGROUND OF THE INVENTION 1. Field of the invention is that of agricultural robotic systems.
    [0002] The invention relates more particularly to a system for automatically adjusting the position of an agricultural implement, such as a tool for cutting or tearing plants. It finds particular application in the automation of mechanical castration operations of seed corn fields. STATE OF THE PRIOR ART Corn is an autogamous plant strongly subject to the effect of heterosis, that is to say to the improvement of the capacities and the vigor of the hybrid species with respect to the pure line self-reproduction. Breeders are seeking to cross two pure breeding lines in order to obtain a hybrid variety that will be more productive and more vigorous. For each line, the male flower, called panicle, is at the top of the plant and is responsible for pollen emission. The female part consists of silks that develop around the ear, closer to the plant's foot, and receive pollen. The objective is therefore to register the panicle of the female spawning rows of one line so that the pollen of the other line comes to be deposited within the bristles of the first. The topping of the male panicle is thus an essential step in the process of producing hybrid maize seed. This topping is done in two stages by two different tools. At first, a knife crossing is performed on the female breeder ranks: rotating blades cut the top of the male plant. The ideal cutting height is three-quarters of the cornet, that is, the leaf surrounding the panicle, from its top or three-quarters of the panicle if it exceeds the horn. Between two and five days later, when the panicle has pushed back a little (2 to 5 cm) but before it is open enough to emit pollen, a pulling on the rollers or the tires is carried out. The objective is to catch the panicle with the rollers or the tires by pulling as little as possible the cornet or the sheets which would be still around. For this, it is necessary to place the rollers at the base of the panicle while remaining above the leaves. The purpose of the first cut is to clear the row so that the panicle protrudes from the foliage, which has remained relatively straight since the tassel grows faster than the leaves. The goal of the second cut is to tear off the rest of the panicle and thus eliminate any risk of self-reproduction. During these operations, the farmer visually assesses the optimum cutting height of the tassel from the nacelle of his machine and actuates a handle that controls the height of the cutting and pulling tools. In addition, two rows are cut simultaneously at the same height which saves time but may penalize cutting one of the two ranks. The quality of the cut is therefore limited by the responsiveness of the driver but also by the precision that the current architecture of the machine allows. As a result, many panicles are not cut to the correct height. At the end of the two stages of mechanical castration, only 70 to 80% of the panicles are eliminated. It is then necessary to iron the rows to tear the remaining panicles by hand because the purity rate to be respected for the production of corn seed is very demanding. Every summer and for a few weeks, farmers hire dozens of workers to do this tedious and painful job. It is therefore sought to carry out these mechanical castration operations in an automated manner in order to improve the efficiency, reduce the costs and reduce the difficulty.
    [0003] Several approaches propose a solution for automatic adjustment of the common two-row cutting height with a measurement sensor specific to each row. The system proposed by US Pat. No. 4,197,691 uses a measurement sensor consisting of vertical rods juxtaposed mounted on a pivoting shaft more or less in contact with the sheets which triggers the sending of a rising signal or descent. However, this contact sensor system requires a permanent adjustment of the cutting height. In addition, two rows are always cut simultaneously at a common height. Other approaches provide distance measurement sensors seen from above, as for the system proposed by US Patent 4,507,910 which studies the measurement and height control during harvesting by a harvester. The sensor used is an ultrasonic sensor located upstream of the threshing wheel. It is placed above crops and measures the relative distance between crops and the sensor. Then a signal is sent to adjust the height of the threshing wheel relative to the desired height for harvesting.
    [0004] The model proposed by US Pat. No. 8,381,502 is similar to the previous system but is adapted to an agricultural corn castration machine. Photocells placed upstream above the maize feet mark the top of the leaves two rows at a time, then send a rising or falling signal to cut the two rows at a common height. Due to differences in heights, ground roughness and vehicle speed, the system constantly attempts to adjust the setpoint to maintain a uniform cutting height. A system proposed by SARL Duissard is also known, based on two batches of transmitting / receiving photocells placed upstream of the cutting tools and located 13 cm one below the other, on either side. two rows. These cells operate in direct detection: an infrared beam is emitted by the photocell while a reflector, located opposite, reflects the beam to the cell that receives it. If corn is on the path of the beam, then it will not be received by the photocell. The maximum height is detected when the lower cell sees corn (the beam obstructed by the maize and therefore not perceived by the lower cell) and the upper cell does not see it (the beam perceived by the upper cell), the precision near the gap between the two photocells is 13 cm. Thus, when both cells see corn (the two bundles are clogged) then the cutting height is too low and a jack lengthens so that the arm carrying the cutting tools goes up. On the other hand, when neither of the two cells see maize (the two bundles are received by the cells) then the cutting height is too high and the rod of the jack returns to lower the arm. . The installation of a delay is necessary to keep the setpoint for several seconds because the detection time and the sending of the setpoint are too short compared to the time required to move the arm.
    [0005] This system thus sends an "all or nothing" instruction to the actuator (up or down) because of the presence of only two photocells. The system therefore tries constantly to adjust the cutting height with repeated and sometimes contrary instructions which solicit strongly. Moreover, as soon as the cells see a void, for example between two feet of corn, the entire arm will descend to have to go up again immediately to the level of the next foot. Similarly, at the end of one row the entire system will descend and probably miss the first few feet of the next row. The degree of precision is also limited by the vertical spacing between the two lots of photocells, 13 cm. The cells further process the information for two rows simultaneously so the lowest rank cornstalk will be cut too high. Finally, the congestion of the overall system remains a problem for farmers. PRESENTATION OF THE INVENTION The invention aims at improving the existing systems for automating cutting or tearing operations of plants, and proposes for this purpose a system 20 for adjusting the height of an agricultural implement, comprising a arm adapted to be controlled to allow raising and lowering the agricultural implement, a height measuring sensor, and a computer configured to provide an instruction to control the height of the arm from the measurements made by the sensor of height measurement, characterized in that the height measuring sensor is an imaging system comprising at least one camera mounted so as to be able to image a scene located in front of the agricultural tool in a direction of travel. a vehicle equipped with the arm, and a computer processing unit configured to develop, from the images delivered by the at least one camera, a 3D reconstruction representative of the relief of the pictorial scene.
    [0006] Some preferred but non-limiting aspects of this system are as follows: the imaging system is a stereoscopic imaging system comprising two cameras mounted so as to be able to image the same scene from two distant points of view, and the computer processing unit is configured to develop the 3D reconstruction from a pair of stereoscopic images delivered by the cameras; the at least one camera of the imaging system is a flight time camera, and the computer processing unit is configured to perform a measurement of 10 flight times between the imaged scene and the camera. the 3D reconstruction provides information representative of the relief of the image scene in matrix form in rows and columns, and the computer processing unit is further configured to identify for each line or line portion of the 3D reconstruction the highest point ; The computer processing unit is configured to identify one or more ranks of plants in the 3D reconstruction; it further comprises a memory in which the measurements made by the height measurement sensor are recorded, the computer being configured to supply the control command of the height of the arm on the basis of measurements previously stored in the memory and corresponding to a plurality of 3D reconstructions of pictorial scenes of which at least one point is at a distance from the current position of the cutting tool less than a predetermined distance. It further comprises a speed measuring sensor in the direction of travel of the vehicle, and the computer is configured to determine the distance traveled along the direction of travel between two successive 3D reconstructions developed by the unit. computer processing; the computer is configured to provide the control command of the height of the arm from the average of said measurements previously stored in the memory; The computer is configured to provide the control command of the height of the arm from the maximum of said measurements previously stored in the memory; the calculator is configured to calculate a leaf density indicating, for each pitch interval of a set of successive intervals, the percentage of measurements of said previously stored measurements in the memory which indicate a height greater than the lower limit of the height interval, and to provide the control command of the arm height from the lower limit of a height interval corresponding to a threshold percentage. BRIEF DESCRIPTION OF THE DRAWINGS Other aspects, objects, advantages and features of the invention will become more apparent upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the accompanying drawings in which: Figure 1 is a schematic perspective view of a system according to a possible embodiment of the invention; Figure 2 is a diagram illustrating the geometric model of a stereoscopic imaging system; Figures 3 and 4 are simplified model diagrams of the arm carrying the agricultural tool and the height measuring sensor; Fig. 5 is a diagram showing a leaf density that can be determined in a possible embodiment of the invention.
    [0007] DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS The invention relates to a system for adjusting the height of an agricultural implement. It is generally applicable to any field where a measurement and a height adjustment are necessary, especially for tools for cutting or tearing plants such as those used for the castration of corn or for harvesting cereal. Referring to Figure 1, the invention relates to a system for adjusting the height of an agricultural implement O. This system is formed of an arm 1 capable of being controlled to allow raising and lowering the agricultural tool, a height measurement sensor 2, and a computer configured to provide an instruction for controlling the height of the arm from the measurements made by the height measurement sensor. The agricultural tool is typically a cutting tool (for example a knife cutting tool) or tearing (for example tires or rollers) of plants. Such a tool generally comprises a cutting or tearing instrument (knives, tires or rollers), an instrument drive motor, a vegetation guide and a protective cover. For corn castration, the vehicle used is a straddle that straddles male breeding lines that will not be cut or torn off and cut or snatch several female breeder ranks at a time. A conventional straddle generally has two or four arms upstream of the vehicle, each arm carrying two cutting or tearing tools to castrate simultaneously two rows at the same height, which saves time but may penalize the cut of one or both rows.
    [0008] In a possible embodiment of the invention, only one cutting or pulling tool is used per arm in order to individualize the cut per crop row. Returning to FIG. 1, the arm 1 comprises a rear vertical upright 11 forming the main structural connection with the agricultural vehicle, and a vertical upright 12 which carries at its lower end a horizontal support bar 25 of agricultural tool 13 which extends perpendicularly to the direction of travel and on which is mounted the agricultural tool O. In an alternative embodiment, the arm can carry several agricultural tools, two typically, for carrying out simultaneous operations on several rows of culture. The vertical uprights 11 and 12 are interconnected by link posts 14 and 15 pivotally mounted relative to the vertical upright 3029389 8 11. A jack 16 is mounted between the rear upright 11 and the upright 14. and provides a means for adjusting the height of the connecting post 14, and thereby the height of the vertical front post 12 and the cutting tool O, by pivoting the connecting post 14 with respect to the rear vertical post 11.
    [0009] The height measurement sensor 2 is an imaging system comprising at least one camera mounted so as to be able to image a scene located in front of the agricultural tool in the direction of travel of the vehicle equipped with the arm. The imaging system further comprises a computer processing unit configured to produce, from the images delivered by the at least one camera, a 3D reconstruction representative of the relief of the imaged scene. The computer processing unit can be deported from the at least one camera. In another possible embodiment, the imaging system is a flight time system comprising a flight time camera and a computer processing unit configured to realize a time of flight measurement between the imaged scene and the flight scene. camera and allow 3D reconstruction. Such a measurement system delivers in real time and at a rate of several tens of Hz a 3D map of the observed environment. It is an active system that illuminates the scene from an infrared flash imperceptible to man but captured by the camera. The sent light pulse is reflected by the surfaces present in the scene and is picked up by the pixel array of the camera. The computer processing unit calculates the pulse return time on each pixel, generally by a phase shift calculation. So for each pixel, we establish the distance between the camera and the point of the surface having reflected the pulse. Indeed, the return time corresponds to the travel time of return / return of the light wave between the camera and the surface. This technology 25 is very similar to Lidar technologies (scanning laser scanner) with the essential advantage of having a 3D image whose pixels are acquired simultaneously, which is advantageous in the context of the invention where the system measuring in motion. The main limitation of this time-of-flight technology concerns the range, a few meters in a favorable environment, and even more limited in the external environment (sensor disturbances by the infrared radiation 3029389 9 solar). But because of the short distance between the camera and the image area as well as the orientation of the camera towards the ground (strong limitation of the risks of glare) make it possible to circumvent this limitation. In another possible embodiment, the imaging system is a stereoscopic system comprising two cameras mounted so as to be able to image, from two distant points of view, the same scene located in front of the agricultural tool in the direction of travel of the vehicle equipped with the arm. Both cameras are carried by a stereoscopic head. The computer processing unit is then configured to develop the 3D reconstruction.
    [0010] The cameras of the stereoscopic imaging system produce at the same time two twin photographs, called stereoscopic pair, slightly spatially shifted. These will allow to restore the relief of the canopy according to the following principle shown in Figure 2 and which comprises the following steps: the calibration of the shooting system; 15 the rectification of the images; the matching of homologous points between the two images (resulting from the projection of the same point of the environment); the reconstruction of the 3D point of the environment from the pairs of homologous points.
    [0011] Since the baseline 3 between the two cameras is assumed to be fixed, the calibration step is made prior to the reconstruction campaign and remains valid as long as the mechanical stability of the stereo head is guaranteed. The following steps are performed at each moment to produce a new 3D reconstruction of the environment to take into account a change in either the vehicle position or the observed surface. The calibration step can be performed by observing a known object (a pattern) from different angles and viewed simultaneously by the two cameras. The mapping on each image pair of several characteristic points of the pattern makes it possible to estimate the projection matrix of each camera (intrinsic parameters) as well as the geometrical transformation connecting the two cameras (extrinsic parameters). The parameters resulting from the calibration make it possible to apply a correction function which aligns the lines of the left camera with those of the right camera: a point P of the environment projected on the line i of the camera 1 will be projected. on the line i of the camera 2. This operation makes it possible to accelerate and make more robust the pairing between the points of the two images corresponding to the same 3D point. The chosen transformation must take care to preserve the quality of the signal contained in the image (minimization of smoothing and interpolation). An example of this type of algorithm is presented in the article by Loop and Chang entitled Computing rectifying homographies for stereo vision Int. Conference CVPR, 1999. Once the two images rectified, a mapping of the images 11 and 12 of the pair of stereoscopic images provided by the cameras is then performed, the purpose of which is to find the homologous points pl, p2 between the two images. , that is to say the projections of the same points P of the pictorial scene. It is thus identified that the point pl (ul, v1) in the left image 11 and the point p2 (u2, v2) in the right image 12 are the projection of the same point P of the image scene. The X, Y, Z coordinates of this point P can then be calculated. To do this, the first image 11 is scanned and for each pixel of this image, the second image 12 acquired at the same time is searched for the pixel corresponding to the same physical point. Thanks to the correction, this pixel is on the same line of the second image 12 as the original pixel of the first image 11. This constraint reduces the search times and the risks of error. To perform the search, we consider a neighborhood of the original pixel and we search along the line 25 the pixel having the most similar neighborhood. Different correlation scores have been proposed in the literature, compromised between quality and speed. This search is iterated for all the pixels of the line of the original image, then to all the lines of this same image. Order constraints between successive pairings as well as so-called "global" algorithms make it possible to consolidate the pairings made by eliminating the aberrant results. For each pairing, the distance between the columns of the two paired pixels can be saved: it is called disparity, this disparity being linearly related to the depth of the corresponding 3D point. During the last step, for each pairing made between the two images and using the knowledge of the calibration parameters of the system, the corresponding 3D point can be reconstructed by triangulation. For all the pairings made between the two images, we reconstruct a set of 3D points whose coordinates are expressed in the reference of one of the cameras (or in an arbitrary reference rigidly linked to one of the cameras). By orienting the at least one camera of the imaging system (stereoscopic or time-of-flight system) to the maize rows, the reconstructed 3D points correspond to points of the canopy. It is thus possible to reconstruct a surface based on these reconstructed 3D points and thus to model the canopy of the pictorial scene. Once reconstructed, this surface can be analyzed to determine the ridges connecting the vertices of the feet belonging to the same rank and the valleys 15 corresponding to the inter-row space. In addition, to facilitate the search for these areas of maximum curvatures, the reconstructed 3D surface being expressed in the reference of the at least one camera and can therefore be expressed in the reference system of the vehicle, the desired ridge lines and valleys are in a direction parallel to the movement of the vehicle.
    [0012] Depending on the width of the field of view of the at least one camera, several ranks can be imaged simultaneously. The imaging system can thus be adapted to allow simultaneously imaging and measuring the height of several rows of culture. The 3D reconstruction thus provides information representative of the relief of the scene imaged in matrix form in lines and columns where each point of the matrix provides information representative of the distance between the imaging system (more precisely the midpoint between the cameras on the baseline 3 in the case of a stereoscopic system) and the top of the plants present in the pictorial scene.
    [0013] The computer processing unit may be configured to identify for each line or line portion of the 3D reconstruction the highest point, or calculate for each line or line portion of the 3D reconstruction the average of the points present on the line. line or portion of line, so as to provide the height measurement information. In one embodiment of the invention, the at least one camera of the imaging system is mounted so as to be stationary relative to the agricultural vehicle. As shown in FIGS. 1 and 3, it can in particular be mounted on the rear vertical upright 11 of the arm 1 which serves as the main structural connection with the agricultural vehicle 10. In this case, the position of the at least one camera of the imaging system 2 is known in the absolute reference of the vehicle and more particularly its absolute height h absolute camera which is constant. The reconstitution of the 3D surface of the canopy at the level of the seedlings upstream of the tool O makes it possible to know the relative relative height of the maize of the top of the plants with respect to the camera. Thus we obtain the absolute height inhabited corn of the top of the plants with the relation: habsolue corn = h absolute camera - hrelative maize with hrelative maize positive. (1) In another embodiment shown in FIG. 4, the at least one camera of the imaging system is mounted to be fixed with respect to the cutting tool O. As shown in FIG. it can in particular be mounted on the top of the vertical upright before 12 of the arm 1. In this case, the absolute height of the camera's camera varies. Thanks to the reconstruction of the 3D surface of the canopy, we know the relative height of the maize top corn relative to the camera. Thus, it is possible to deduce the absolute height of corn from the top of the seedlings with the relation: habsolue corn = h absolute camera - hrelative maize with hrelative maize positive. (1) 25 In this case, it is necessary here to calculate the absolute height of the camera camera, which is expressed by: habsolue camera = habsolue tools + Tools-camera (2) 3029389 13 With habsolue tools calculated later and Houtils -came the constant height between the tool (s) O and the camera. A simplified model of the arm with tool (s) O and the height measurement sensor upstream in the direction of travel is proposed in FIG. 2. The acquisitions 5 are made for example every millisecond. However, the setpoint is calculated for example every 100 ms, from a number of acquisitions preceding the calculation. An inverter coupled to a motor can be used to control the elongation of the jack 16, here electric. The voltage sent to the drive is connected to the motor angular position by the relation: ° motor = 1 (360 Cverin) U variator Umax drive (3) 10 With Umax drive the maximum voltage that can be sent to the drive (10V for example), Cverin the stroke of the electric cylinder (300 mm for example) and p the pitch of the motor screw (10mm / rev for example). The invention extends however to other types of cylinders, including hydraulic cylinders. During an acquisition, the elongation of the jack 16 is recovered by means of an angular position sensor, for example a resolver, then in the case of FIG. 4, it is necessary to find the absolute height of the tool's tools. tool O by geometry to deduce the absolute height habsolue maize corn. During the calculation loop of the setpoint, the absolute heights of the maize can be treated according to different strategies, examples of which will be presented below, in order to obtain the height-of-cut instruction, that is to say the setpoint. absolute height of the tools. The latter is then converted into cylinder extension and voltage which is sent to the drive. The objective is first of all to know the relation between the elongation of the cylinder and the absolute height of the tools as well as that between the absolute height of the tools and the absolute height of the corn, in order to be able to apply the different strategies to the 25 heights absolute maize. The engine position sensor makes it possible to know the number of increments nincrements of the engine driving the jack 16 which is to be converted into engine position engine ° then elongation cylinder X elongation through the formulas: 2 / r ° engine - 2m nincrements - ° initial motor (4) 3029389 14 Xlength - 2, .6 motor (5) With m increment unit (20 for motor used), p screw pitch (10mm / rev for cylinder used) and ° initial motor the initial position of the engine. To compute the tools according to X elongation, the angle θ 0 is used between the vertical upright 11 and the connecting amount 14. By geometry, the following relation is obtained: 2 L21 + L23 + L24 + I-1 + 2sin0 (LiL3 - L4112) - (10 + X elongation j = (6) 2COS0 (L1H243L4) Hence, (10 + X elongation j = L12 + L32 + L42 + H22 + 2sin (O - a) ', / ( LiL3 - L4112) 2 + (Id 1112 + L 3 L 4) (7) With (sin a) (2 (L11-12431.4)) a = atan = atan ,, .. ii cos Cr L 1,11 , 3 - L 4112) Thus: ## EQU2 ## where ## STR1 ## more, we have: cos0 = H1 + H2 -113 - habsolue tools L2 So we obtain the following relation, necessary in the case of the figure 4: 20 habsolue tools = H1 + H2 - H3 - L2 COSO (10) On the other hand once the height setpoint has been calculated using the different strategies, ie the height of the tools to which the tools are to be placed. uver at the time when the plant to be cut is located at the level of the tools, it is necessary to know the setpoint which corresponds in terms of elongation of the cylinder X elongation For this, thanks to the relation (9) the necessary angle 0 is calculated to get the habsolue tools desired height. Then equation (6) makes it possible to deduce (11): (8) (9) 3029389 extension = 1 + 12 + L 32 + L 42 + H 22 + 7 i ar -1-3 -1 H - 7 CO n, a 1-2 + -3-4, 10 (11) Furthermore, one can take care to limit the elongation setpoint between 0 and the stroke of the jack (300 mm for the cylinder used) in order not to obtain negative instructions or greater than the maximum elongation of the cylinder. Finally, one calculates the voltage Uariator, between Umin drive and Umax drive (between 0 and 10V for the drive used), to send to the drive thanks to the formula (12): Umax drive - Umin drive 10 Uvariateur = extension Umin drive Cverin ( 12) The development by the computer of the command setpoint of the height of the arm (determination of actual tools and hence of the variator) from the measurements made by the height measuring sensor (measurement of 15) is described below. hrelative maize). The objective of the cut with the knives is to clear the view on the row by cutting just enough leaves and panicles so that they can still push back later. The cut must therefore be relatively homogeneous, without creating too many irregularities. The ideal cutting height is three-quarters of the panicle. This involves locating the height of the base and top of the panicle to locate three quarters, which is difficult to reproduce with sensors, especially since the panicle can be hidden in the cornet. In addition, imposing a cutting height to a certain number of centimeters below the top of the foot is not suitable because the panicle may as well be close to this vertex as much lower. It is therefore necessary to obtain a relative measure, adapted to each foot of maize and to different architectures of plants (upright growth, drooping leaves, etc.). When pulling, it is necessary to remove all panicles that have repelled. As the panicles grow faster than the leaves, the goal is to keep the leaves evenly above the panicle. For this, it is necessary to limit abrupt variations in height during cutting in order to then follow these variations during tearing. For the pulling, it is necessary to come to place the rollers or the tires as close as possible to the top of the leaves in order to tear out the panicles that protrude without removing too much leaves.
    [0014] Several strategies can therefore be envisaged according to their relevance for cutting or grubbing up. Each strategy can be based on the fact that the elapsed time between two 3D reconstructions elaborated by the height measurement imaging system is converted into distance traveled thanks to the speed calculated at each instant. The imaging system developing 3D reconstructions of scenes located upstream of the tool or tools, the instruction to be sent to the actuator at a time t is not calculated thanks to the reconstruction developed at the same time t but thanks to previous reconstructions. Thus, the reconstructions are memorized progressively and then the setpoint is calculated from a small sample of reconstructions of pictorial scenes of which at least one point is at a distance from the current position of the cutting tool, in the vehicle travel direction, less than a predetermined distance dEch. The setpoint sent is thus calculated from the previous reconstructions performed while the imaging system imaged the canopy over a distance dEch in the direction of travel of the vehicle upstream of the current position of the tool or tools.
    [0015] Thus, the system according to the invention may furthermore comprise a memory in which the measurements made by the height measurement sensor are recorded, and the computer may be configured to supply the control instruction of the height of the arm on the base. measurements previously recorded in the memory and corresponding to several 3D reconstructions of pictorial scenes of which a point at least 25 is at a distance from the current position of the cutting tool less than the predetermined distance dEch- In the context of this mode of realization, it is important to know precisely the speed of movement at each moment of development of a 3D reconstruction in order to work not in time elapsed but in distance traveled.
    [0016] To do this, the system may include a sensor for measuring the speed of travel in the vehicle travel direction, and the computer is then configured to determine the distance traveled along the travel direction between two measurements. successively realized by the height measurement sensor. In other words, it is possible to time stamp the samples in memory with the instantaneous speed, then to make it possible to determine, at the time of calculating the height setpoint, which are the samples corresponding to the 3D reconstructions carried out while the imaging system imaged the canopy over the distance dEch in the vehicle's travel direction upstream of the current position of the tool (s) (more or fewer samples depending on whether the movement is fast or slow).
    [0017] The forward speed measuring sensor may consist of an inductive proximity sensor associated with a plastic wheel fixed in the rim of a vehicle wheel and on the periphery of which metal pins are arranged. At each passage in front of a metal pin, the signal at the output of the sensor is modified. Thus, the forward speed can be deduced by calculating the elapsed time between two output signal edges, i.e. between two metal pins, knowing the length of the string between these two points. For each acquisition, we memorize the maximum absolute height of maize habsolue maize- Then we calculate the height set habsolue tools to which the tools must come cut the plant.
    [0018] This calculation can be done in different ways depending on the chosen strategy. In one embodiment, the computer is configured to provide the control setpoint of the arm height from the average of said measurements previously made by the height measurement sensor over said predetermined distance dEch. This embodiment corresponds to a strategy called "average" according to which for the acquisitions of dEch, one calculates the average height of corn. The instruction sent habsolue tools is then equal to this average height to which we can subtract a height hoffset that depends on the variety cut. This strategy has the advantage of encompassing the voids between two feet. It is intended to be used for cutting knives. In another embodiment, the computer is configured to provide the control command of the height of the arm from the maximum of said measurements previously made by the height measurement sensor on said predetermined distance dEch. This embodiment corresponds to a so-called "maximum" strategy according to which, for the acquisitions of dEch, the maximum height among the heights of corn on this sample is determined. The instruction sent to the tools is then equal to this maximum height at which we can subtract a height hOffset that depends on the cut variety. This strategy is more for pulling up the rollers. It has indeed been verified that the panicles measuring about 10 mm in diameter are not detectable by the light curtain, only the leaves are detected by drawing a relatively straight profile after cutting the knives. The objective here is therefore to place the rollers just at the top of this profile, knowing that everything that exceeds can only be the tassel and will be torn off. In yet another embodiment, the computer is configured to calculate a leaf density indicating, for each pitch interval of a set of successive intervals, the percentage of measurements among said measurements previously made by the height measurement sensor. over said predetermined distance dEch which indicate a height greater than the lower limit of the height interval, and to provide the control command of the height of the arm from the lower limit of the height interval corresponding to a threshold percentage .
    [0019] This embodiment corresponds to a so-called "leaf density" strategy according to which for the dEch acquisitions, the minimum height among the corn heights on this sample is identified. Then a loop is created which defines a current height equal to the minimum incremented height of 5 mm for example at each loop turn and the percentage of acquisitions which correspond to a height greater than this new current height is calculated. Thus, for the minimum height 3029389 19 of the sample, 100% of the acquisitions of the sample have a height greater than the minimum height. Then as the current height increases, fewer and fewer acquisitions have a height greater than the current height. This percentage corresponds to what is called a leaf density. FIG. 5 shows an example of a leaf density that can be determined in this embodiment. On the y-axis is the height of the hreiative maize plants and on the x-axis the percentage of plants higher than this hreiative maize height- A threshold S is defined from which it is estimated that the leaf density is sufficiently low (30% in the example of FIG. 5) to correspond to the optimum cutting height: in fact, the closer one gets to the top of the plant, the more the leaf density is supposed to decrease. It will be noted that conversely the leaf density can be estimated starting from the maximum height and coming to verify the percentage of acquisitions having a lower height. The instruction sent habsolue tools is then equal to the current height corresponding to this threshold S (around + 175mm in the example of Figure 5), to which we can subtract a height hoffset that depends on the cut variety. This strategy is intended to be used for knife cutting. It is closer to the ideal measure of three quarters of panicles: indeed, we imagine that at this ideal height there is only a certain percentage of leaves. In addition, it takes into account the architecture of the plant: for a variety with drooping leaves, there will be more leaves around the panicle than for an upright variety. The invention is not limited to the system as previously described but also extends to a vehicle, including a straddle, equipped with one or more systems according to the invention. It also extends to a method of adjusting the height of an agricultural implement by means of a system comprising an operable arm for raising and lowering the agricultural implement, comprising the steps of to acquire measurements of a height measurement sensor, the height measurement sensor being an imaging system comprising at least one camera mounted so as to be able to image the same scene located in front of the tool in a direction of travel of a vehicle equipped with the arm, and a computer processing unit configured to produce, from the 20 images delivered by the at least one camera, a 3D reconstruction representative of the relief of the pictorial scene. ; - Determining a control command of the arm height from the acquired measurements.
    [0020] The invention provides a gain in accuracy by coming to determine a height set quantified, accurate and adapted to each foot of corn through the development of calculation algorithms adapted to the issues of cutting and tearing. In addition, the invention also brings a gain in productivity since the system can be reproduced on several arms to cut or tear several rows simultaneously, independently of each other. Finally, this system makes it possible to reduce the hardness of the work of the farmer, who no longer has to constantly watch for corn heights and adjust the height of the tools. Thus, this system improves the profitability of the mechanical castration operations and reduces the number of remaining panicles to tear by hand. 15
    权利要求:
    Claims (13)
    [0001]
    REVENDICATIONS1. An agricultural implement height adjusting system (0), comprising an arm (1) operable to raise and lower the agricultural implement, a height measuring sensor, and a calculator configured to provide an arm height control setpoint from the measurements made by the height measuring sensor, characterized in that the height measuring sensor is an imaging system (2) comprising at least one mounted camera so as to image a scene located in front of the agricultural tool in a travel direction of a vehicle equipped with the arm, and a computer processing unit configured to develop, from the images delivered by the at least one camera, a 3D reconstruction representative of the relief of the pictorial scene.
    [0002]
    2. System according to claim 1, wherein the imaging system is a stereoscopic imaging system (2) comprising two cameras mounted so as to be able to image the same scene from two distant points of view, and in which computer processing unit is configured to develop the 3D reconstruction from a pair of stereoscopic images delivered by the cameras.
    [0003]
    3. System according to claim 1, wherein the at least one camera of the imaging system is a flight time camera, the computer processing unit being configured to perform a measurement of flight time between the scene and the image. camera.
    [0004]
    4. System according to one of claims 1 to 3, wherein the 3D reconstruction providing information representative of the relief of the scene imaged in matrix form in rows and columns, the computer processing unit is further configured to identify for each line or line portion of the 3D reconstruction the highest point. 3029389 22
    [0005]
    5. System according to one of claims 1 to 4, wherein the computer processing unit is configured to identify one or more ranks of plants in the 3D reconstruction. 5
    [0006]
    6. System according to one of claims 1 to 5, further comprising a memory in which are recorded the measurements made by the height measurement sensor, the computer being configured to provide the control command of the height of the arm on the base of measurements previously stored in the memory and corresponding to several 3D reconstructions of pictorial scenes of which a point at least 10 is at a distance from the current position of the cutting tool less than a predetermined distance.
    [0007]
    The system of claim 6, further comprising a forward speed measuring sensor in the vehicle travel direction, and wherein the calculator is further configured to determine the distance traveled along the direction of travel. path between two 3D reconstructions successively developed by the computer processing unit.
    [0008]
    8. System according to one of claims 6 and 7, wherein the computer is configured to provide the control command of the arm height from the average of said measurements previously stored in the memory.
    [0009]
    9. System according to one of claims 6 and 7, wherein the computer is configured to provide the control command of the height of the arm from the maximum 25 said measurements previously stored in the memory.
    [0010]
    10. System according to one of claims 6 and 7, wherein the computer is configured to calculate a leaf density indicating, for each height interval of a set of successive intervals, the percentage of measurements among said previously recorded measurements. in the memory which indicate a height greater than the lower limit of the height interval, and to provide the command reference of the arm height from the lower limit of a height interval corresponding to a threshold percentage. .
    [0011]
    11. System according to one of claims 1 to 10, wherein the agricultural tool is a tool for cutting or tearing plants, especially maize.
    [0012]
    Vehicle equipped with a system according to one of claims 1 to 11.
    [0013]
    A method of adjusting the height of an agricultural implement (0) by means of a system comprising an arm (1) operable to raise and lower the agricultural implement, including steps: - acquisition of measurements of a height measurement sensor, the height measurement sensor being an imaging system (2) comprising at least one camera mounted so as to image a scene located in front of The agricultural tool in a direction of travel of a vehicle equipped with the arm, and a computer processing unit configured to produce, from the images delivered by the at least one camera, a 3D reconstruction representative of the relief of the scene. pictorial; determination of a control command of the height of the arm from the measurements acquired.
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    同族专利:
    公开号 | 公开日
    FR3029389B1|2017-01-13|
    WO2016087529A1|2016-06-09|
    EP3226672A1|2017-10-11|
    US20180279556A1|2018-10-04|
    EP3226672B1|2018-11-28|
    US10172289B2|2019-01-08|
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    法律状态:
    2015-12-31| PLFP| Fee payment|Year of fee payment: 2 |
    2016-06-10| PLSC| Publication of the preliminary search report|Effective date: 20160610 |
    2016-12-29| PLFP| Fee payment|Year of fee payment: 3 |
    2018-01-02| PLFP| Fee payment|Year of fee payment: 4 |
    2019-12-31| PLFP| Fee payment|Year of fee payment: 6 |
    2020-12-28| PLFP| Fee payment|Year of fee payment: 7 |
    2021-12-31| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1462003A|FR3029389B1|2014-12-05|2014-12-05|SYSTEM AND METHOD FOR AUTOMATICALLY ADJUSTING THE HEIGHT OF AN AGRICULTURAL TOOL USING 3D RECONSTRUCTION|FR1462003A| FR3029389B1|2014-12-05|2014-12-05|SYSTEM AND METHOD FOR AUTOMATICALLY ADJUSTING THE HEIGHT OF AN AGRICULTURAL TOOL USING 3D RECONSTRUCTION|
    EP15804457.8A| EP3226672B1|2014-12-05|2015-12-02|System and method for the automatic adjustment of the height of an agricultural implement using 3d reconstruction|
    US15/531,617| US10172289B2|2014-12-05|2015-12-02|System and method for the automatic adjustment of the height of an agricultural implement using 3D reconstruction|
    PCT/EP2015/078386| WO2016087529A1|2014-12-05|2015-12-02|System and method for the automatic adjustment of the height of an agricultural implement using 3d reconstruction|
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