法国专利FR3048085A1 ACCELEROMETER OF MAGNETIC LEVITATION WITH HIGH PRECISION

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专利摘要:
The present invention relates to a high precision magnetic levitation accelerometer for measuring the linear acceleration of the flying apparatus, comprising a magnetic shielding vacuum chamber system, a luminous interference displacement detection system, a control system magnetic and a small magnetic body serving as a test mass. With the implementation of the light interference detection technique, the accelerometer accurately measures the position and attitude of the small magnetic body in real time, and the magnetic levitation technology is applied to accurately place the small magnetic body in its position. and his attitude, so that the small body serving as a test piece is always in the center of the control system chamber.
公开号:FR3048085A1
申请号:FR1751323
申请日:2017-02-20
公开日:2017-08-25
发明作者:Liqing Pan；Zhihui Luo；Xianwei Yang；Hua Zhao；Mingxue Shao；Qiongying Ren；Chao Tan；Min Liu；Chao Wang；Chao Zhang；Sheng Zheng；Hongguang Piao；Guangze Lu；Yunli Xu；Xiufeng Huang
申请人:China Three Gorges University CTGU；
IPC主号:

专利说明:

MAGNETIC LEVITATION ACCELEROMETER WITH HIGH PRECISION TECHNICAL FIELD
The present invention relates to the field of acceleration measuring apparatus, more particularly to a high-precision accelerometer with magnetic levitation.
STATE OF THE ART
Accelerometers are used as instruments for measuring satellite-based linear acceleration, where the accuracy of these instruments is the key to improving measurement accuracy when gravimetric measurement satellites are used to measure the overall gravitational field, which allows to increase the measurement accuracy of the global gravitational field and to establish an altitudinal criterion. High precision accelerometers are also used to improve the spatial ambience model, increasing the accuracy of measurement and prediction of satellite orbits. For high-altitude orbiting satellites, the calculation and orbiting can be done by measuring the solar pressure. These accelerometers can also be used to monitor the micro-gravitational environment of space devices for the tests that are going on in them. Several high-precision accelerometers can be a gradiometer of gravity.
Depending on the movements of the test mass, accelerometers are classified as linear or pendulum accelerometers. According to the detection method for which if the input is controlled by the output, there are open loop accelerometers and others in closed loop. The electrostatic levitation accelerometers commonly used are restricted by the machining processes at the orthogonality of the electrodes and the symmetry of the electrical panels, in addition, the impact of circuit noise, noise due to parasitic forces, and ambient noise is important.
STATEMENT OF THE INVENTION
The present invention aims to circumvent restrictions of high precision machining processes, by proposing a magnetic levitation accelerometer which ensures better measurement accuracy.
For this, the present invention proposes the following solution.
A high-precision magnetic levitation accelerometer, comprising: a vacuum chamber magnetic shielding system, a light interference displacement detection system, a magnetic levitation control system, and a small magnetic body serving as a proof mass. The vacuum chamber magnetic shielding system comprises an outer magnetic shielding chamber and an internal chamber of the system, said internal chamber of the system being within said outer magnetic shielding chamber, said internal chamber of the system being under vacuum said small magnetic body serving as test mass being inside said internal chamber of the system. Said light interference displacement detection system, which is above said internal chamber of the system, sends light signals to said small magnetic body serving as proof mass and receives light signals reflected by the latter to obtain the position and attitude of said small magnetic body serving as a test mass in real time. Said magnetic levitation control system also located above said internal chamber of the system, controls in real time the position and attitude of said small magnetic body serving test mass by putting the latter constantly levitating in the center of said internal chamber of the system which coincides with the center of mass of the flying apparatus.
With the implementation of the proposed solution, advantageously, the high-precision magnetic levitation accelerometer according to the invention has the qualities of high-precision electrostatic levitation accelerometers and avoids manufacturing difficulties of sensitive structures in terms of machining. . The vacuum chamber magnetic shielding system is simple to perform. The position and the attitude of said small magnetic body serving as test mass can be precisely measured with the light interference displacement detection system, avoiding effects due to light ray pathways. It can also be precisely controlled with the magnetic levitation control system. In addition, the acceleration of the flying apparatus is proportional to the current of the position control coil, which makes it possible to measure the acceleration with high accuracy.
For its purpose, the present invention proposes another solution which is the following.
A high-precision magnetic levitation accelerometer, comprising: a vacuum chamber magnetic shielding system, a magnetic displacement sensing system, a magnetic levitation control system, and a small magnetic body serving as a proof mass. The vacuum chamber magnetic shielding system comprises an outer magnetic shielding chamber and an internal chamber of the system, said internal chamber of the system being inside said outer magnetic shielding chamber, said internal chamber of the system being unladen. said small magnetic body serving as test mass being inside said internal chamber of the system. The magnetic displacement sensing system includes a plurality of high precision magnetic sensors located in different locations of said internal chamber of the system. The position and the attitude of said small magnetic body serving as test mass are obtained in real time with the measurement of magnetic fields of said small magnetic body serving as test mass by these magnetic sensors. The magnetic levitation control system includes a plurality of position control coils located symmetrically on the left wall and the right wall of said internal chamber of the system, and a plurality of attitude control coils located symmetrically on the walls. upper, lower, front and rear of said internal chamber of the system. With the position control coils and the attitude control coils, said magnetic levitation control system receives feedback from said magnetic displacement detection system, and controls in real time the position and attitude of said small body magnetic test mass by putting the latter constantly levitating in the center of said internal chamber of the system which coincides with the center of mass of the flying apparatus.
With the implementation of this proposed solution, advantageously, the high-precision magnetic levitation accelerometer according to the invention has the qualities of high-precision electrostatic levitation accelerometers and avoids manufacturing difficulties of sensitive structures in terms of machining. . The vacuum chamber magnetic shielding system is simple to perform. The position and attitude of said small magnetic body serving as a proof mass can be accurately measured with the high precision magnetic sensors. The magnetic levitation control system can precisely control said small magnetic body serving as a test mass, performing acceleration measurements with high accuracy.
In the case of the high-precision accelerometer of magnetic levitation:
Advantageously, the light interference displacement detection system comprises a plurality of pairs of probes of the interferometer, each pair of which is connected to an optical device for detecting displacement by light interference by an optical fiber, the interferometer being of Michelson type or Fabry-Perot type; said interferometer probes being in the different locations of said internal chamber of the system; by each pair of probes, a light source sends light signals to said small magnetic body serving as test mass and receives light signals reflected by the latter, light signals carrying information of the position and attitude of said small magnetic body serving as test mass being transmitted to the optical displacement detection device which processes the light signals, by the principle of light interferences, to transform the displacement and the angle of deflection of said small magnetic body serving as mass of test in identifiable luminous changes, and for which with the measurements by each pair of probes, the displacement of the small magnetic body serving as test mass with respect to the center of the internal chamber of the system and its angles of rotation with respect to the two axes perpendicular to the magnetic moment are calculated, by principle of vector addition, and then sent in response to the magnetic levitation control system to control in real time the position and attitude of the small magnetic body serving as a test mass.
According to a particular embodiment, the interferometer comprises 5 pairs of probes, of which 3 pairs are on the X axis of the internal chamber of the system, more precisely on its left and right walls; a pair is on the Y axis of the chamber internal to the system, more precisely in the center of its upper and lower walls, to measure the displacement by translation along the Y axis of the small magnetic body serving as test mass; and a pair is on the Z axis of the chamber internal to the system, more precisely in the center of its front and rear walls, to measure the displacement by translation along the Z axis of the small magnetic body serving as test mass; among those on the X axis of the chamber internal to the system, a pair of the right wall being on the Y axis and symmetrical with respect to the center of the right wall, to measure the rotation of the small magnetic body serving as mass of test with respect to the Z axis; a pair of the right wall being on the Z axis and symmetrical with respect to the center of the right wall, for measuring the rotation of the small magnetic body serving as test mass with respect to the Y axis; and a pair being in the center of the left and right walls, to measure the translation displacement along the X axis of the small magnetic body serving as test mass.
Said magnetic levitation control system advantageously comprises a plurality of position control coils located symmetrically on the left wall and the right wall of said internal chamber of the system, and a plurality of attitude control coils lying symmetrically on the upper, lower, front and rear walls of said internal chamber of the system, with position control coils and attitude control coils, said magnetic levitation control system receives feedback from said magnetic displacement detection system , and control in real time the position and the attitude of said small magnetic body serving test mass by putting the latter constantly levitating in the center of said internal chamber of the system which coincides with the center of gravity of the flying apparatus.
Preferably on the two right-hand walls of the internal chamber of the system, 4 pairs of position control coils are symmetrical with respect to the axis X and are fed with currents of different directions and different values, so that the the center of the mass of the small magnetic body serving as a proof mass is maintained at that of the internal chamber of the system.
Advantageously, a pair of attitude control coils are provided at the upper and lower wall centers on the Y axis, and a pair of attitude control coils are provided at the front and rear wall centers on the Z axis. the size of the attitude control coils being much larger than that of the magnetic body serving as a proof mass to achieve precise control of the latter, so that the equivalent magnetic moment of the small magnetic body serving as test mass either in the X-axis direction. According to a particular embodiment, when the translational displacement and the rotation of the small magnetic body serving as a proof mass is controlled, the electromagnetic force by position control coils counterbalancing the acceleration of the flying apparatus caused by nonconservative forces, so as to maintain the center of mass of the small magnetic body serving as the test mass and that of the flying apparatus in coincidence, the relation between the vector of the electromagnetic force F and that of the acceleration a being F = ma, where m is the mass of the small magnetic body serving as mass of test, the electromagnetic force being proportional to the magnetic field generated by position control coils which is proportional to the current supplied, the measurement of the acceleration of the flying apparatus being then performed by the currents supplying the position control coils .
Advantageously said small magnetic body serving test mass is cylindrical.
According to a particular embodiment, said small magnetic body serving as test mass is made of permanent magnetic material, or said small magnetic body serving as test mass has a core of permanent magnetic material and this core is enveloped by non-magnetic materials .
In the case of the high-precision magnetic levitation accelerometer, when the translational displacement and rotation of the small magnetic body serving as the proof mass is controlled, the electromagnetic force of the position control coils counterbalances the acceleration of the magnetism. flying apparatus caused by non-conservative forces, maintaining the center of mass of the small magnetic body serving as a test mass and that of the flying apparatus in coincidence, the relation between the vector of electromagnetic force F and that of the acceleration a being F = ma, where m is the mass of the small magnetic body serving as a proof mass, the electromagnetic force being proportional to the magnetic field generated by position control coils which is proportional to the current supplied, the measurement the acceleration of the flying apparatus being thus carried out by the currents supplying the control coils position.
Advantageously, the magnetic field measured by a magnetic sensor depends on the position and the attitude of the small magnetic body serving as test mass and for which the position and the attitude of the small magnetic body serving as test mass at all times are obtained by the following calculation using a computer program according to the resolution formula of the magnetic field at the point of detection,
for which the magnetic inductions of the n detection points are known, a system of equations with 3n of nonlinear equations for which there are six unknowns: χ0, γ0, ζ0, α, β andM; when n> 2, is solved with a non-linear method.
According to a particular embodiment, said magnetic levitation control system comprises 4 pairs of position control coils and 2 pairs of attitude control coils, the position control coils being fed with currents of different directions and different values, so that the center of the mass of the small magnetic body serving as a proof mass is maintained at that of the internal chamber of the system, and the attitude control coils being used to control the attitude of the small body the magnetic mass serving as a test mass, so that the equivalent magnetic moment of the latter is in the direction of the x-axis.
According to a particular embodiment for which said small magnetic body serving test mass is ellipsoid rotary, or round or cylindrical.
Advantageously, said small magnetic body serving as test mass is made of permanent magnetic material, or said small magnetic body serving as test mass has a core of permanent magnetic material and this core is enveloped by non-magnetic materials.
PRESENTATION OF FIGURES
In order to more clearly illustrate the embodiments and the prior art of the present invention, the figures necessary for the description of embodiments are given by way of example, and it is obvious that other figures can be derived from from these figures provided for a person skilled in the art, without an inventive step. Among these figures, - Figure 1 is the schematic structure of the first embodiment of a high-precision accelerometer of magnetic levitation according to the invention; FIG. 2 is the theoretical diagram of the detection of a displacement by optical interference; - Figure 3 schematically illustrates the measurement of the deflection angle of a small magnetic body serving as a test mass; FIG. 4 illustrates the schematic structure of a levitation control system of a small magnetic body serving as a test mass; FIGS. 5-7 are schematic analyzes of the forces undergone by a magnetic dipole in a magnetic field; - Figure 8 schematically illustrates a torque applied to a small magnetic body serving as a test mass by a first attitude control coil; - Figure 9 schematically illustrates a torque applied to a small magnetic body serving as a test mass by a second attitude control coil; FIG. 10 is the schematic structure of the second embodiment of a high-precision magnetic levitation accelerometer according to the invention; - Figure 11 illustrates theoretically the essential theory of the technology of detecting a displacement in a magnetic field.
DETAILED DESCRIPTION OF EMBODIMENTS
With the accompanying drawings, the present invention will be described in an even clearer and more complete manner. It is clear that the embodiments described are merely a part of the embodiments of the present invention. On the basis of these, all other embodiments that one skilled in the art can achieve without inventive step is of course within the scope of the present invention.
In order to make apparent the objectives, features and advantages of the present invention, it will be described in more detail with the accompanying drawings and embodiments described hereinafter.
As shown in FIG. 1, the high-precision magnetic levitation accelerometer according to the invention comprises: a vacuum chamber magnetic shielding system, a light interference displacement detection system, a magnetic levitation control system and a small magnetic body b serving as a test mass. The vacuum chamber magnetic shielding system comprises an outer magnetic shielding chamber and a chamber internal to the system, said internal chamber to the system being inside said outer magnetic shielding chamber, said internal chamber to the system being empty. said small magnetic body b serving as test mass being within said internal chamber of the system. In FIG. 1, the chamber internal to the system is dimensioned as 10 cm × 10 cm × 10 cm, with a void ratio of 10 5 Pa and a temperature stability of less than 10 -2 K / Hz 1/2. Said small magnetic body serving Test mass is permanent magnetic material and cylindrical, with a magnetic moment M = 6.25 X 10 "2 Air, i2 and a mass of 1g. In order to reduce the external disturbances on the acceleration measurements of the small magnetic body b serving as a test mass, the latter is enveloped by non-magnetic materials, increasing its mass to 0.1 kg.
The light interference displacement detection system, which is located above said internal chamber of the system, sends light signals to the small magnetic body b serving as test mass and receives light signals reflected by the latter in order to obtain the position and the attitude of said small magnetic body b serving as a test mass in real time. Said magnetic levitation control system also located above said chamber internal to the system, controls in real time the position and the attitude of said small magnetic body b serving test mass by putting the latter constantly levitating in the center of said internal chamber in the system coincides with the center of mass of the flying apparatus.
As shown in FIG. 2, the light interference displacement detection system comprises a plurality of probe pairs of the interferometer. Each pair of probes 31 is connected to an optical device 33 for detecting displacement by light interference by an optical fiber 32. The probes 31 of the interferometer are located in the various locations of said internal chamber of the system.
Through each pair of probes 31, a light source sends light signals to said small magnetic body b serving as test mass and receives light signals reflected by the latter. Light signals carry information of the position and the attitude of said small magnetic body serving as test mass and are transmitted to the optical displacement detection device 33 which process the light signals, by the principle of light interferences, for transforming the displacement and the angle of deflection of said small magnetic body b serving as test mass into identifiable light signals. With the measurements by each pair of probes 31, the displacement of the small magnetic body serving as test mass with respect to the center of the chamber internal to the system and its angles of rotation with respect to the two axes perpendicular to the magnetic moment are calculated by the principle of vector addition, then sent in reaction to the magnetic levitation control system in order to control in real time the position and attitude of the small magnetic body serving as test mass.
It is expected that the interferometer has 5 pairs of probes. Of these, 3 pairs are on the X axis of the chamber internal to the system, specifically on its left and right walls; a pair is on the Y axis of the chamber internal to the system, more precisely in the center of its upper and lower walls, to measure the displacement by translation along the Y axis of the small magnetic body serving as test mass; and a pair is on the Z axis of the chamber internal to the system, more precisely in the center of its front and rear walls, to measure the translation displacement along the Z axis of the small magnetic body serving as a test mass. Among those on the X axis of the internal chamber of the system, the probes of a pair of the right wall are on the Y axis and symmetrical with respect to the center of the right wall, to measure the rotation of the small magnetic body serving test mass with respect to the Z axis; the probes of a pair of the right wall are on the Z axis and symmetrical with respect to the center of the right wall, to measure the rotation of the small magnetic body serving as test mass with respect to the Y axis; and the probes of a pair are at the centers of the left and right walls, to measure the translational displacement along the X axis of the small magnetic body serving as a test mass.
A first method of detection of displacement by light interference is as follows.
Consider an Michelson interferometer with equal arms as an example, and analyze the displacement measurement of the small magnetic body serving as a test mass. (1) Measurement of displacement by translation of the small magnetic body serving as test mass Since the small magnetic body b serving as test mass is of cylindrical shape, height h and radius r and that the origin The marker system is the center of the internal chamber of the system. As shown in FIG. 2, in the initial state, the small magnetic body b serving as a test mass is located in the center of the chamber internal to the system and its cylinder axis coincides with the axis X of the marking system. a pair of probes 31_1 and 31_1 'located on the centers of the walls of the chamber in the direction of the X axis. This pair of probes emit light signals arriving at the small magnetic body b serving as a test mass in two points (h / 2, 0, 0) and (-h / 2, 0, 0) as detection points. The phase of the light signals emitted by this pair of probes and then reflected by the small magnetic body b serving as a proof mass is zero, the output of the light interference displacement detection system being a constant continuous signal. When the small magnetic body b serving as a proof mass moves with a translation of AX towards the positive direction of the X axis, for the arms of the interferometer which connects this pair of probes, the step of light ray in the sense negative increases by 2AX and that in the positive direction decreases by 2AX, the cumulative variation of these two light signals being:
(1) then, the corresponding phase shift is:
(2) where λ is the wavelength emitted by the laser source. The ΔΦΧ phase shift can be sent to the digital phase demodulation circuit 34 by the Michelson interferometer 33 with equal arms. The translation displacement along the X axis of the small magnetic body b serving as a test mass is thus obtained:
(3)
Likewise, two pairs of probes respectively for the Y and Z axes make it possible to detect displacements by translation along these two axes. (2) Measurement of the deflection angle of the small magnetic body serving as a test mass Since the small magnetic body serving as test mass rotates along the Z axis, and the angle of deflection is Θ , we have
(4) where e is the vertical distance between the two probes 31 _2 and 31 _2 ', where e is a constant. Al is the length of the projection on the X axis of the line connecting the detection points to the small magnetic body serving as test mass, and these detection points are formed with the light signals emitted by this pair of probes . The variation of the ray of light rays received by the two probes 31 _2 and 31 _2 'is then 2AI, with a variation of phase shift:
(5) and
(6)
We then have the angle of deflection around the Z axis of the small magnetic body serving as mass: (7)
Similarly, the angle of deflection around the Y axis of the small magnetic body serving as a test mass can be obtained with a pair of probes which are located at the upper wall of the chamber internal to the system and are orthogonal. with probes 31 _2 and 31_2 '.
In addition, when the small magnetic body serving as a mass rotates along an axis, the probes 31_1 and 31_1 'increase or decrease in the same light beam step, ie the phase shift of the received signals is zero. The rotation of the small magnetic body serving as test mass therefore has no consequence on the measurement of its displacement by translation.
The theoretical accuracy of the measurement by the general luminous interference is in the nanometer range, on the other hand, the introduction of a Michelson interferometer with equal arms and the detection method with the difference between two arms make it possible to a 4-fold increase in measurement accuracy and possibly lower accuracy than a nanometer. The rotational detection measurement accuracy of the small magnetic body serving as the proof mass is less than 0.002 degrees per second.
A second light interference displacement detection method is as follows.
Measurement of the displacement of the small magnetic body b serving as test mass can also be carried out with a detection device of the Fabry-Perot interferometer (F-P) type. As shown in FIG. 2, when the small magnetic body b serving as test mass moves with a translation of AX towards the positive direction of the X axis, the variation in the length of the wave detected by the probes 31_1 and 31_1 'connecting FP type detection device is:
(8) Where λ0 is the length of the center wave of the interference spectrum, 1 is the length of the FP interferometer chamber, ng is the index of refraction of the index, and the measured variation of l comprises the translation displacement Δλ of the test mass. With the displacement demodulation device 34 which compensates for errors due to the environment, a measurement accuracy in the order of the pm is obtained. This method avoids the effects of varying the light intensity on the measurement and having a measurement system that is more invulnerable to jamming. Moreover, according to a one-to-one relationship between the chamber length of the F-P interferometer and the interferometer spectrum peak distances, displacement measurement is an absolute measure. Likewise, two pairs of probes for the Y and Z axes, respectively, make it possible to detect displacements by translation along these two axes.
For the measurement of the deflection angle of the small magnetic body serving as a test mass, Al of the formula (4) is the displacement measured by the probes 31 _2 and 31_2 'connecting the detection device 33 of the F-P type. We then have the angle of deflection of the small magnetic body serving as test mass rotates along the Z axis,
(9)
Similarly, the deflection angle around the Y axis of the small magnetic body serving as mass can be obtained with a pair of probes which are located at the upper wall of the chamber internal to the system and are orthogonal with the probes. 31 _2 and 31_2 '. The rotational detection measurement accuracy of the small magnetic body serving as a mass is less than 0.002 degrees per second, with the F-P interference technology.
As shown in Figure 4, the magnetic levitation control system includes 4 pairs of position control coils and 2 pairs of attitude control coils. On the two left-hand walls of the internal chamber of the system, 4 pairs of position control coils are symmetrical with respect to the X axis. These position control coils are fed with currents of different directions and different values. so that the center of mass of the small magnetic body serving as test mass is maintained at that of the internal chamber of the system. A pair of attitude control coils are provided at the upper and lower wall centers on the Y axis, and a pair of attitude control coils are provided at the front and rear wall centers on the Z axis. size of the attitude control coils is much larger than that of the magnetic body serving as a test mass to achieve precise control of the latter, so that the equivalent magnetic moment of the small magnetic body serving as a test mass is In addition, the currents can be fed precisely through 7 orders of magnitude, for example from 1nA to 10mA.
With the position control coils 41 and the attitude control coils 42, said magnetic levitation control system receives feedback from said light interference displacement detection system, and controls in real time the position and attitude of said a small magnetic body serving as a test mass by constantly placing the latter in levitation at the center of said internal chamber of the system which coincides with the center of mass of the flying apparatus.
For the 4 pairs of position control coils whose diameters are all 0.56 cm and the number of turns are all 100, the coordinates of their centers in the reference of Figure 1 are: (-5 cm, 1 cm, 0), (5 cm, 1 cm, 0), (-5 cm, 0, 1 cm), (5 cm, 0, 1 cm), (-5 cm, -1 cm, 0), (5 cm, -1 cm, 0), (-5 cm, 0, -1 cm), (5 cm, 0, -1 cm). For the 2 pairs of attitude control coils whose diameters are all 1.2 cm and the number of turns are all 100, the coordinates of their centers in the reference of FIG. 1 are: (0.5 cm, 0 ), (0, -5 cm, 0), (0, 0, 5 cm), and (0, 0, -5 cm).
The control method of the small magnetic body serving as test mass is as follows.
When the size of the small magnetic body serving as test mass is very small, it is considered as a magnetic couple whose magnetic moment is M. For a magnetic couple which is in a magnetic field whose magnetic induction is B, there is a double effect. First, when the direction of the torque is different from that of the external field, the torque undergoes a moment of rotation M x B and turns to the position in which it has the same meaning as the magnetic field. At this position, the magnetic pair has a status where the potential energy reaches its minimum, and magnetic charges of different signs are approaching, those of the same signs are moving away. If the external field is heterogeneous, the differences of the magnetic inductions between positions where magnetic charges of positive and negative sign are found lead to the magnetic torque receiving a resultant force whose direction points to the stronger field. When the magnetic field is homogeneous, the resultant force is zero.
As shown in FIGS. 5 to 7, a toroidal current generates a gradient magnetic field. A magnetic couple in the latter undergoes both a moment of rotation and a translational force, whereas, that which is in a homogeneous magnetic field undergoes only one moment of rotation, the resultant translation force being nothing. Thus, a moment of rotation can be achieved by a homogeneous magnetic field, while a translational force can be realized by a gradient magnetic field, thus, the position and attitude control of the small magnetic body serving as a mass of test is carried out.
The position control of the small magnetic body serving as test mass Since the magnetic moments of the 4 pairs of position control coils are M1, M1, M1, Mc, M1, and M4. These coils generate magnetic fields at the position of the small magnetic body serving as test mass. As the size of the small magnetic body serving as test mass is very small, it is considered a magnetic couple. To show the direction of the moment of the coils, the moments are denoted as (t = 1,2,3,4,1 ', 2', 3 ', 4'). Mt represents the value of magnetic moment, and φ indicates the direction of magnetic moment, the magnetic moment being along the positive direction of the X axis with St = 1 and following the negative direction of the X axis with $ = -1.
Note that the magnetic moment of the small magnetic body serving as test mass is M and calculate its electromagnetic force by the control coils. Take the first pair 1 and 1 'as an example. Let us first calculate the electromagnetic control force of M, where M is the vector of M towards, the coordinates of the center of M being (x, y, z) and the coordinates of M1 with respect to the center being (a, b , vs). We then,
(10) their interaction potential is:
(11)
With (12) (13) (14) (15) the electromagnetic force experienced by the small magnetic body serving as a test mass is:
(16) (17) (18)
In the same way, for the control of M by, by a strict symmetry, the coordinates of the center of M ^ are (-a, b, c), and r , = (-a - χ) ΐ + (b - y) j + (c - z) k, its action potential with M is:
(19) we then
(20) (21) (22)
Since x - »0, y -> 0, z -> 0, the commands are carried out so that the center of mass of the small magnetic body serving as proof mass remains at the origin of the mark. Moreover, the first pair of control coils 1 and 1 'of position are symmetrical strictly with respect to an axis and of the same size, with the same current, so we have,
(23)
Thus, for the first pair of position control coils 1 and 1 'to be able to control individually the three divisional vectors on the three axes of the electromagnetic force of the small magnetic body serving as test mass, it is sufficient to control δ ±, δ2 and (a, b, c). (1) for the first pair of position control coils 1 and 1 ', let's take
We then,
(24) the divisional force along the Y axis is thus controlled individually.
Moreover, when δ ± = 1, δν = -1 or δ ± = -1, δν = 1, c = 0, we have,
(25) the divisional force along the X axis is thus controlled individually. (2) for the second pair of position control coils 2 and 2 ', take δ2 = δ2, = 1 or - 1, and b = 0, we have
(26) The divisional force along the Z axis is thus controlled individually.
Moreover, when δ2 = 1, δ2, = -1 or δ2 = -1, δ2, = 1, b = 0, we have,
(27) the divisional force along the X axis is thus controlled individually. (3) for the third pair of position control coils 3 and 3 ', take δ3 = 1, δ3ι = -1 or δ3 = -1, δ3, = 1 and c = 0, we have
(28) The divisional force along the X axis is thus controlled individually. Similarly, the third pair can control the divisional force along the Y axis individually. (4) for the fourth pair of position control coils 3 and 3 ', the operation is similar to that of the previous three pairs. It is therefore necessary 3 pairs of position control coils to simultaneously control the displacement by translation along the three axes X, Y, Z. This fourth pair 4 and 4 'serves as a redundant pair that will replace those among the other three pairs that are out of order to control the corresponding divisional force.
The attitude control of the small magnetic body serving as test mass
The control of the attitude of the small magnetic body serving as test mass is achieved with the two pairs of attitude control coils 5, 5 ', 6, 6' whose magnetic moments are denoted as ΈΙ, ΈΙ, M ^, M ^ ,. Magnetic inductions generated by these coils at the position of the small magnetic body serving as test mass are 5 ^. The distance between the centers of the coils and the origin of the mark is 1. As the coils of each pair are of the same size and with the same current (same value and direction), we have ΈΙ = M ^, (1) The first pair of attitude control coils 5 and 5 ': as the mounts FIG. 8, if the magnetic moment of the small magnetic body serving as test mass derives from the direction of the X axis, then undergoes a moment of force f5 generated by the first pair of attitude control coils 5 and 5. 'and we have
(29)
Since the size of the first pair of attitude control coils 5 and 5 'is larger than the small magnetic body serving as proof mass, the magnetic field generated at the location of the latter may be considered as a field approximately homogeneous whose direction is at the Y axis. According to the method of computation of the field of a magnetic couple, we have
(30) the corresponding moment of force is of value
(31) and it is perpendicular to the plane formed by M and Under the effect of this moment of force, M will rotate from the Y axis to the X axis in the XY plane. (2) The second pair of attitude control coils 6 and 6 ': as shown in FIG. 9, it is similar for this pair to the first pair of attitude control coils at the control level of the small magnetic body serving as a test mass. Under the effect of the moment of force%, M will rotate from the Z axis to the X axis in the XZ plane and we have
(32)
In summary, the direction of the magnetic moment of the small magnetic body serving as test mass can be maintained in that of the X axis with these two coils.
The high accuracy measurement of acceleration.
When the translational displacement and rotation of the small magnetic body serving as a proof mass is controlled, the electromagnetic force generated by position control coils counterbalances the acceleration of the flying apparatus caused by non-conservative forces, for maintain the center of mass of the small magnetic body serving as a test mass in coincidence with that of the flying apparatus. We have a relation between the vector of the electromagnetic force F and that of the acceleration a: F = ma, where m is the mass of the small magnetic body serving as test mass. The electromagnetic force is proportional to the magnetic field generated by position control coils which is proportional to the current supplied. Thus, the measurement of the acceleration of the flying apparatus can be performed by the currents fed to the position control coils.
Advantageously, the high-precision magnetic levitation accelerometer according to the invention exhibits the qualities of high-precision accelerometers of electrostatic levitation, avoiding difficulties in manufacturing sensitive structures in terms of machining. The vacuum chamber magnetic shielding system is simple to perform. The position and the attitude of the small magnetic body serving as test mass can be precisely measured with the light interference displacement detection system, avoiding effects due to light ray paths. They can also be precisely controlled with the magnetic levitation control system. In addition, the acceleration of the flying apparatus is proportional to the current of the position control coil, which makes it possible to measure the acceleration with high accuracy.
By simulation on Earth, we have obtained the main characteristics of high-precision magnetic levitation accelerometers such as the noise power spectral density which is better than 10-8m * s-2 * Hz-1/2 and the measurement band which is 5 - 100 mHz.
Another embodiment of the accelerometer will be presented to measure the linear acceleration of the flying apparatus. As shown in FIG. 10, a high-precision magnetic levitation accelerometer according to the invention comprises a vacuum chamber magnetic shielding system, a magnetic displacement detection system, a magnetic levitation control system and a small magnetic levitation system. magnetic body 10 serving as test mass. The vacuum chamber magnetic shielding system includes an outer magnetic shielding chamber and an internal chamber 7 of the system. The internal chamber 7 of the system is located inside said outer magnetic shielding chamber, and is under vacuum. The small magnetic body serving as test mass is inside the internal chamber 7 of the system. The magnetic displacement detection system comprises a plurality of high precision magnetic sensors 8 which are in different locations of the internal chamber of the system. The position and the attitude of the small magnetic body 10 serving as test mass are obtained in real time with the measurement of magnetic fields of the small magnetic body serving as test mass by these magnetic sensors. The magnetic levitation control system has a plurality of position control coils located symmetrically on the left wall and the right wall of the internal chamber of the system, and a plurality of attitude control coils located symmetrically on the walls. upper, lower, front and rear of the internal chamber of the system. With the position control coils and the attitude control coils, the magnetic levitation control system receives feedback from said magnetic displacement detection system, and controls in real time the position and attitude of said small body magnetic 10 serving test mass by putting the latter constantly levitating in the center of said internal chamber of the system which coincides with the center of mass 9 of the flying apparatus. The small magnetic body 10 serving as proof mass may be the same as that of the previous embodiment.
In this embodiment, eight high-precision magnetic sensors 8 are attached to the vertices of the internal chamber of the system. The magnetic field data measured by these sensors make it possible to locate the position and the attitude of the small magnetic body serving as a test mass in real time.
The small magnetic body 10 serving as test mass may be rotary ellipsoid, round, or cylindrical, or other shapes. The size of the small magnetic body serving as test mass or its magnetic moment are known precisely.
In this embodiment, the method of controlling the position and attitude of the small magnetic body 10 serving as proof mass is identical to that of the previous embodiment, as well as measuring the acceleration. The high-precision magnetic levitation accelerometer according to the invention is made of non-magnetic materials, whose magnetic permeability rate is identical to that of vacuum. Thus, the distribution of the magnetic field generated by the small magnetic body serving as test mass depends only on its position and its attitude. Moreover, the measured magnetic field also depends on the detection point. As shown in Figure 11, take the magnetic sensor related reference as the general reference. Suppose that the center of mass coordinates of the small magnetic body serving as the proof mass is (x0, y0, z0), that those of the detection point are (x, y, z) and that the distance between the center of mass the small magnetic body serving as test mass and the detection point is r. When r is greater than the size of the small magnetic body serving as proof mass, the latter can be considered approximately as a magnetic couple. Suppose that the equivalent magnetic moment of the small magnetic body serving as a test mass is M which has for an azimuth angle α and an elevation angle β in a spatial reference (attitude of the small magnetic body serving as a test mass ).
According to the resolution formula of the magnetic field at the point of detection, we have
Suppose that the magnetic inductions of the n detection points are known. We can then formulate a system of equations with 3n nonlinear equations for which there are six unknowns: x0, y0, z0, α, β andM. When n> 2, the system is overdetermined and can then be solved with a nonlinear method. This equation system can be solved using a computer program. Thus, the position and the attitude of the small magnetic body serving as test mass at any time are obtained.
With a magnetic displacement detection system using a high-precision sensor, for example, with a sensitivity of 0.01 nT, the location accuracy is less than 2 nm and the accuracy of rotation measurement is less than 0, 02 degrees per second.
The magnetic levitation control system comprises 4 pairs of position control coils and 2 pairs of attitude control coils. As shown in FIG. 10, with different currents supplied for the 4 pairs of position control coils (1, 1 '), (2, 2'), (3, 3 ') and (4, 4'), the three divisions along the X, Y and Z axes of the electromagnetic force of the small magnetic body serving as a test mass are individually controlled and its position is also controlled. Finally, the center of mass of the small magnetic body serving as test mass coincides with that of the internal chamber of the system which is also that of the flying apparatus. With the two pairs of attitude control coils (5, 5 '), (6, 6'), the attitude of the small magnetic body serving as test mass is controlled, so that the magnetic moment of the small body The magnetic field serving as test mass is maintained in the X-axis direction. In addition, the currents can be fed precisely over 7 orders of magnitude, for example from 1 nA to 10 mA. The high-precision magnetic levitation accelerometer according to the invention has the qualities of high-precision electrostatic levitation accelerometers and avoids manufacturing difficulties of sensitive structures in terms of machining. The vacuum chamber magnetic shielding system is simple to perform. The position and attitude of the small magnetic body serving as proof mass can be precisely measured with high precision magnetic sensors. The magnetic levitation control system can precisely control the small magnetic body serving as test mass, performing acceleration measurements with high accuracy.
By simulation on Earth, we have obtained the main characteristics of high-precision magnetic levitation accelerometers such as the noise power spectral density which is better than 10-8m * s-2 * Hz-1/2 and the measurement band which is 5 - 100 mHz.
The described embodiments are in progressive order. Each embodiment highlights the differences with others that can be accessed for the same or similar parts.
The principle and embodiments are described using the specific examples, and exemplary embodiments serve to understand the method of the present invention as well as its basic theories. The invention described with reference to the embodiments described is not limited to them, but covers any modification that the skilled person is able to achieve.

权利要求:
Claims (15)
[1" id="c-fr-0001]
1 - Accelerometer with high precision magnetic levitation, characterized in that it comprises a magnetic vacuum chamber shielding system, a light interference displacement detection system, a magnetic levitation control system and a small magnetic body serving test mass, said vacuum chamber magnetic shielding system comprising an outer magnetic shielding chamber and an internal chamber of the system, said internal chamber of the system being inside said outer magnetic shielding chamber, said chamber internal system being empty, said small magnetic body serving as test mass being inside said internal chamber of the system; said light interference displacement detection system, which is above said internal chamber of the system, sending light signals to said small magnetic body serving as proof mass and receiving light signals reflected by the latter to obtain the position and attitude of said small magnetic body serving as a test mass in real time; said magnetic levitation control system which is located above said internal chamber of the system, controlling in real time the position and the attitude of said small magnetic body serving as a test mass by putting the latter constantly levitating in the center of said internal chamber of the system which coincides with the center of mass of the flying apparatus.
[2" id="c-fr-0002]
The high-precision magnetic levitation accelerometer according to claim 1, wherein: said light interference displacement detection system comprises a plurality of probe pairs of the interferometer each pair of which is connected to an optical displacement detecting device by light interference by an optical fiber, the interferometer being Michelson type or Fabry-Perot type; said interferometer probes being in the different locations of said internal chamber of the system; by each pair of probes, a light source sends light signals to said small magnetic body serving as test mass and receives light signals reflected by the latter, light signals carrying information of the position and attitude of said small magnetic body serving as test mass being transmitted to the optical displacement detection device which processes the light signals, by the principle of light interferences, to transform the displacement and the angle of deflection of said small magnetic body serving as mass of test in identifiable luminous changes, and for which with the measurements by each pair of probes, the displacement of the small magnetic body serving as test mass with respect to the center of the internal chamber of the system and its angles of rotation with respect to the two axes perpendicular to the magnetic moment are calculated, by principle of vector addition, and then sent in response to the magnetic levitation control system to control in real time the position and attitude of the small magnetic body serving as a test mass.
[3" id="c-fr-0003]
3 - Accelerometer high-precision magnetic levitation of claim 2, wherein the interferometer comprises 5 pairs of probes, 3 pairs are on the X axis of the internal chamber of the system, more precisely on its left and right walls; a pair is on the Y axis of the chamber internal to the system, more precisely in the center of its upper and lower walls, to measure the displacement by translation along the Y axis of the small magnetic body serving as test mass; and a pair is on the Z axis of the chamber internal to the system, more precisely in the center of its front and rear walls, to measure the displacement by translation along the Z axis of the small magnetic body serving as test mass; among those on the X axis of the chamber internal to the system, a pair of the right wall being on the Y axis and symmetrical with respect to the center of the right wall, to measure the rotation of the small magnetic body serving as mass of test with respect to the Z axis; a pair of the right wall being on the Z axis and symmetrical with respect to the center of the right wall, for measuring the rotation of the small magnetic body serving as test mass with respect to the Y axis; and a pair being in the center of the left and right walls, to measure the translation displacement along the X axis of the small magnetic body serving as test mass.
[4" id="c-fr-0004]
A high-precision magnetic levitation accelerometer according to claim 1, wherein said magnetic levitation control system comprises a plurality of position control coils located symmetrically on the left wall and the right wall of said internal chamber of the system, and a plurality of attitude control coils located symmetrically on the upper, lower, front and rear walls of said internal chamber of the system, with the position control coils and the attitude control coils, said control system of magnetic levitation receives reactions from said magnetic displacement detection system, and controls in real time the position and attitude of said small magnetic body serving as a test mass by constantly putting the latter in levitation at the center of said internal chamber of the system which coincides with the center of gravity of the apparatus nt.
[5" id="c-fr-0005]
5 - Accelerometer high-precision magnetic levitation according to claim 4, wherein on the two left-right walls of the internal chamber of the system, 4 pairs of position control coils are symmetrical with respect to the X axis and are powered with currents of different directions and different values, so that the center of mass of the small magnetic body serving as test mass is maintained at that of the internal chamber of the system.
[6" id="c-fr-0006]
The high-precision magnetic levitation accelerometer of claim 4, wherein a pair of attitude control coils are provided at the upper and lower wall centers on the Y axis, and a pair of attitude control coils. are provided at the front and rear center centers on the Z axis, the size of the attitude control coils being much larger than that of the magnetic body serving as a test mass to achieve precise control of the latter, so that the equivalent magnetic moment of the small magnetic body serving as test mass is in the direction of the X axis.
[7" id="c-fr-0007]
7 - A high-precision magnetic levitation accelerometer according to claim 4, wherein when the translational displacement and the rotation of the small magnetic body serving as proof mass is controlled, the electromagnetic force by position control coils counterbalancing the acceleration of the flying apparatus caused by nonconservative forces, so as to maintain the center of mass of the small magnetic body serving as a test mass and that of the flying apparatus in coincidence, the relation between the vector of the electromagnetic force F and that of acceleration a being F = ma, where m is the mass of the small magnetic body serving as a proof mass, the electromagnetic force being proportional to the magnetic field generated by position control coils which is proportional to the powered current, the measurement of the acceleration of the flying apparatus being then carried out by the currents supplying the position control coils.
[8" id="c-fr-0008]
8 - Accelerometer high-precision magnetic levitation according to any one of the preceding claims, wherein said small magnetic body serving test mass is cylindrical.
[9" id="c-fr-0009]
9 - A high-precision magnetic levitation accelerometer according to any one of the preceding claims, wherein said small magnetic body serving as test mass is permanent magnetic material, or said small magnetic body serving test mass has a core permanent magnetic material and this core is enveloped by non-magnetic materials.
[10" id="c-fr-0010]
10 - Accelerometer with high precision magnetic levitation, characterized in that it comprises a magnetic vacuum chamber shielding system, a magnetic displacement detection system, a magnetic levitation control system and a small magnetic body serving test mass, said vacuum chamber magnetic shielding system having an outer magnetic shielding chamber and an internal chamber of the system, said internal chamber of the system being inside said outer magnetic shielding chamber, said chamber internal system being vacuum, said small magnetic body serving as test mass being within said internal chamber of the system; said magnetic displacement sensing system having a plurality of high precision magnetic sensors located in different locations of said internal chamber of the system, wherein the position and attitude of said small magnetic body serving as test mass is obtained in real time with the measurement of magnetic fields of said small magnetic body serving as test mass by these magnetic sensors; said magnetic levitation control system having a plurality of position control coils which are symmetrically located on the left wall and the right wall of said internal chamber of the system, and a plurality of attitude control coils which are located symmetrically on the upper, lower, front and rear walls of said internal chamber of the system, with position control coils and attitude control coils, said magnetic levitation control system receiving feedback from said motion detection system by means of magnetic, and controlling in real time the position and attitude of said small magnetic body serving test mass by putting the latter constantly levitating in the center of said internal chamber of the system which coincides with the center of mass of the flying apparatus .
[0011]
11 - A high-precision magnetic levitation accelerometer according to claim 10, wherein when the translational displacement and the rotation of the small magnetic body serving as a proof mass is controlled, the electromagnetic force of the position control coils counterbalances the acceleration. of the flying apparatus caused by nonconservative forces, maintaining the center of mass of the small magnetic body serving as a test mass and that of the flying apparatus in coincidence, the relation between the vector of the electromagnetic force F and that of acceleration a being F = ma, where m is the mass of the small magnetic body serving as a proof mass, the electromagnetic force being proportional to the magnetic field generated by position control coils which is proportional to the current supplied, the measurement of the acceleration of the flying apparatus being thus carried out by the food currents t the position control coils.
[12" id="c-fr-0012]
12- high-precision magnetic levitation accelerometer according to claim 10, wherein the magnetic field measured by a magnetic sensor depends on the position and the attitude of the small magnetic body serving test mass and for which the position and the attitude of the small magnetic body serving as test mass at any time are obtained by the following calculation using a computer program according to the resolution formula of the magnetic field at the point of detection,

for which the magnetic inductions of the n detection points are known, a system of equations with 3n of nonlinear equations for which there are six unknowns: χ0, γ0, ζ0, α, β andM; when n> 2, is solved with a non-linear method.
[13" id="c-fr-0013]
A high-precision magnetic levitation accelerometer according to claim 10, wherein said magnetic levitation control system comprises 4 pairs of position control coils and 2 pairs of attitude control coils, the position control coils being fed with currents of different directions and different values, so that the center of mass of the small magnetic body serving as a proof mass is maintained at that of the internal chamber of the system, and the attitude control coils being used to control the attitude of the small magnetic body serving as test mass, so that the equivalent magnetic moment of the latter is in the direction of the x-axis.
[14" id="c-fr-0014]
14- A high-precision magnetic levitation accelerometer according to any one of claims 10 to 13, wherein said small magnetic body serving test mass is ellipsoid rotatable, or round or cylindrical.
[15" id="c-fr-0015]
15- high-precision magnetic levitation accelerometer according to any one of claims 10 to 14, wherein said small magnetic body serving test mass is permanent magnetic material, or said small magnetic body serving test mass has a core of permanent magnetic material and this core is enveloped by non-magnetic materials.

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公开号 | 公开日

FR3048085B1|2019-07-19|

US20170242050A1|2017-08-24|

US10444257B2|2019-10-15|

引用文献:

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

US5485748A|1994-01-26|1996-01-23|Zeamer; Geoffrey H.|Magnetically levitated force/weight measurement system|

WO2000054060A1|1999-03-05|2000-09-14|Iwaki Electronics Co., Ltd.|Displacement sensor and movement information collecting device comprising the same|

US7252001B2|2002-09-02|2007-08-07|Ecole Polytechnique Federale De Lausanne |Three axis active magnetic levitation for inertial sensing systems|

US6898970B2|2003-06-05|2005-05-31|International Business Machines Corporation|Inertial navigation device for ion propulsion driven spacecraft|

JP2005283428A|2004-03-30|2005-10-13|Denso Corp|Dynamic quantity sensor unit|CN108645407A|2018-04-23|2018-10-12|中国科学院光电研究院|A kind of compound no drag mode realization device and method towards high-precision independent navigation|

US11119116B2|2019-04-01|2021-09-14|Honeywell International Inc.|Accelerometer for determining an acceleration based on modulated optical signals|

US11079227B2|2019-04-01|2021-08-03|Honeywell International Inc.|Accelerometer system enclosing gas|

US10956768B2|2019-04-22|2021-03-23|Honeywell International Inc.|Feedback cooling and detection for optomechanical devices|

US10705112B1|2019-04-22|2020-07-07|Honeywell International Inc.|Noise rejection for optomechanical devices|

US11119114B2|2019-07-17|2021-09-14|Honeywell International Inc.|Anchor structure for securing optomechanical structure|

RU2721589C1|2019-07-23|2020-05-20|Акционерное общество «Информационные спутниковые системы» имени академика М.Ф. Решетнёва»|Space accelerometer|

US11150264B2|2019-08-13|2021-10-19|Honeywell International Inc.|Feedthrough rejection for optomechanical devices using elements|

CN113484538A|2021-07-05|2021-10-08|南京大学|Acceleration measurement method based on anti-magnetic suspension mechanical system|

法律状态:
2018-02-28| PLFP| Fee payment|Year of fee payment: 2 |

2018-11-30| PLSC| Publication of the preliminary search report|Effective date: 20181130 |

2020-02-28| PLFP| Fee payment|Year of fee payment: 4 |

2021-02-26| PLFP| Fee payment|Year of fee payment: 5 |

优先权:

申请号 | 申请日 | 专利标题

CN201610090220.7|2016-02-18|

CN201610090218.XA|CN105675920B|2016-02-18|2016-02-18|Quiet magnetic suspension accelerometer in high precision|

CN201610090218.X|2016-02-18|

CN201610090220.7A|CN105738653B|2016-02-18|2016-02-18|High-precision optical is displaced magnetic suspension accelerometer|

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