Calibration device and method for a pose sensor

Abstract

The application provides a calibration device and method for a pose sensor, the calibration device comprising: a fixed base; a moving platform fixed to the fixed base, the moving platform being used for fixing a rotating shaft, the moving platform being movable along the horizontal plane in the transverse and longitudinal directions; a fixed frame comprising a fixed platform, a first limiting part and a second limiting part, the fixed platform being used for placing the pose sensor, the pose sensor being arranged outside the rotating shaft, the first limiting part being arranged on the fixed platform; the first limiting part abutting against the pose sensor to limit the circumferential movement of the pose sensor, the second limiting part abutting against the fixed base to limit the movement of the fixed frame; the rotating shaft is moved by moving the moving platform to calibrate the pose sensor. The calibration device in the application can significantly improve the calibration efficiency of the pose sensor.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, and specifically relates to a calibration device and method for a pose sensor. Background Technology

[0002] The pose sensor provides pose measurement information for the magnetic levitation rotary joint control system based on the eddy current displacement sensor. The accuracy of the pose sensor's parameters directly affects the control precision of the magnetic levitation rotary joint. Therefore, it is necessary to calibrate the scaling factor, nonlinearity, and zero position of the eddy current displacement sensor in the pose sensor.

[0003] However, existing calibration methods for pose sensors are only suitable for calibrating displacement measurement channels in one degree of freedom direction, failing to meet the calibration requirements for multiple displacement measurement channels within two degrees of freedom. Calibrating multiple displacement measurement channels within two degrees of freedom requires multiple setups and separate calibrations for each channel, which introduces additional calibration errors and results in low calibration efficiency. Therefore, it is necessary to research a calibration device and method that can meet the calibration requirements for multiple displacement channels within two degrees of freedom of pose sensors. Summary of the Invention

[0004] This invention provides a calibration device and method for a pose sensor, which can meet the calibration requirements of an eddy current displacement sensor in multiple directions within two degrees of freedom, while significantly improving the calibration efficiency of the pose sensor.

[0005] In a first aspect, embodiments of the present invention provide a calibration device for a pose sensor, comprising:

[0006] Fixed base;

[0007] A mobile platform is fixed on the fixed base. The mobile platform is used to fix the rotating shaft and can move along the horizontal and vertical directions of the horizontal plane.

[0008] The fixing frame includes a fixing platform, a first limiting part and a second limiting part. The fixing platform is used to place the pose sensor, which is disposed outside the rotation axis. The first limiting part is disposed on the fixing platform.

[0009] The first limiting part abuts against the pose sensor to restrict the circumferential movement of the pose sensor, and the second limiting part abuts against the fixed base to restrict the movement of the fixed frame;

[0010] The pose sensor is calibrated by moving the mobile platform to drive the rotation axis to move.

[0011] Preferably, it also includes a vibration isolation platform, wherein the fixed base and the fixed frame are both fixed on the vibration isolation platform.

[0012] Preferably, the first limiting part is provided with a groove, and the pose sensor is provided with a protrusion. The groove and the protrusion are inserted and engaged to limit the circumferential movement of the pose sensor.

[0013] Preferably, the fixed platform is provided with a through hole for the rotating shaft to pass through, the diameter of the through hole being larger than the diameter of the rotating shaft and smaller than the diameter of the pose sensor.

[0014] In a second aspect, the present invention provides a calibration method for a pose sensor, wherein calibration is performed based on the calibration apparatus described in any one of the first aspects above, comprising:

[0015] The pose sensor is placed on the fixed platform;

[0016] The mobile platform is moved to move the rotation axis, thereby calibrating the pose sensor.

[0017] Preferably, the step of moving the mobile platform to drive the rotation axis to move, thereby calibrating the pose sensor, includes:

[0018] The pose sensor and the calibration device are zero-position adjusted;

[0019] Within the measurement range of the pose sensor, n preset displacement measurement values ​​P are taken. i The moving platform is moved to drive the rotating axis to n nominal displacement measurement points respectively, and the n measured displacement values ​​output by the pose sensor are determined as D. i ;

[0020] Based on n preset displacement measurement values ​​P i and n measured displacement values ​​D i This allows for the calibration of the pose sensor.

[0021] Preferably, the moving platform is moved to drive the rotating shaft to n nominal displacement measurement points respectively, and the n measured displacement values ​​output by the calibration device are respectively determined as D. i ,include:

[0022] With the center of the rotation axis as the origin O, establish a plane rectangular coordinate system OXY on a horizontal plane perpendicular to the central axis of the rotation axis;

[0023] The fixed angle between each eddy current displacement sensor in the pose sensor and the OX axis of the plane rectangular coordinate system is determined as α;

[0024] The moving platform is moved a first distance along the OX axis of the Cartesian coordinate system, and the displacement platform is moved a second distance along the OY axis of the Cartesian coordinate system. The n measured displacement values ​​output by the pose sensor are respectively determined as D. i .

[0025] Preferably, the first distance is P i cosα, the second distance is P i sinα.

[0026] Preferably, the step of using n preset displacement measurement values ​​P i and n measured displacement values ​​D i The pose sensor is calibrated, including:

[0027] Based on the n preset displacement measurement values ​​P i and n measured displacement values ​​D i Calculate the scaling factor K and zero position Z of each eddy current displacement sensor in the pose sensor;

[0028] The scaling factor K and zero point Z of each eddy current sensor in the pose sensor are calculated using the following formulas:

[0029]

[0030]

[0031] In the formula, P i D is the preset displacement measurement value. i The measured displacement value is n, which is a positive integer, and S0 is the measurement range of the pose sensor.

[0032] Preferably, the nonlinearity L of each eddy current sensor in the pose sensor is calculated using the following formula:

[0033]

[0034] In the formula, P i D is the preset measurement value. i The measured displacement value is n, which is a positive integer, and S0 is the measurement range of the pose sensor.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] This invention provides a calibration device and method for a sensor. The calibration device includes a fixed base, a movable platform, and a fixed frame. A rotating shaft is fixed on the movable platform, and the pose sensor is placed outside the rotating shaft. The rotating shaft is moved by moving the movable platform in the horizontal and vertical directions in the horizontal plane, thereby completing the calibration of the pose sensor. When calibrating multiple displacement measurement channels of a pose sensor using the calibration device of this invention, the pose sensor only needs to be placed on the fixed platform, and the calibration of multiple displacement measurement channels in the pose sensor can be completed by moving the movable platform. This not only avoids the error caused by repeatedly installing the pose sensor and improves the calibration accuracy of the pose sensor, but also improves the calibration efficiency of the pose sensor. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a cross-sectional structural schematic diagram of a calibration device for a pose sensor provided in an embodiment of the present invention;

[0039] Figure 2 This is a cross-sectional structural schematic diagram of a calibration device for a pose sensor provided in another embodiment of the present invention;

[0040] Figure 3 This is a cross-sectional view of a pose sensor placed in a calibration device according to an embodiment of the present invention;

[0041] Figure 4 This is a top view of a pose sensor placed in a calibration device according to an embodiment of the present invention;

[0042] Figure 5 This is a top view of a pose sensor placed in a calibration device according to another embodiment of the present invention;

[0043] In the figure, 100: fixed base; 200: moving platform; 300: rotating shaft; 400: fixed frame; 401: fixed platform; 402: first limiting part; 403: second limiting part; 500: pose sensor; 600: vibration isolation platform; 4021: groove; 5001: protrusion; 5002: eddy current displacement sensor. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0045] Generally speaking, the specifications of a pose sensor directly affect the measurement accuracy of the object under test. Therefore, calibrating the specifications of the pose sensor before use is crucial. A pose sensor provides pose measurement information based on the detection signals of eddy current displacement sensors. To measure the displacement of the object under test in multiple directions in the horizontal plane, it is generally necessary to coordinate eddy current displacement sensors in different displacement measurement channels. Therefore, it is necessary to calibrate the eddy current displacement sensors in different displacement measurement channels of the pose sensor. However, existing calibration devices and methods are only suitable for calibrating pose sensors with a displacement measurement channel in one direction within one degree of freedom. They cannot meet the calibration requirements of pose sensors with displacement measurement channels in multiple directions within two degrees of freedom. Calibrating multiple displacement measurement channels of the pose sensor requires multiple mounting and calibrating operations, which introduces additional calibration errors, resulting in poor calibration accuracy and low calibration efficiency.

[0046] Based on the above issues, such as Figure 1 As shown, an embodiment of the present invention provides a calibration device for a pose sensor, comprising:

[0047] Fixed base 100;

[0048] The mobile platform 200 is fixed on the fixed base 100. The mobile platform 200 is used to fix the rotating shaft 300. The mobile platform 200 can move along the horizontal and vertical directions of the horizontal plane.

[0049] The fixing frame 400 includes a fixing platform 401, a first limiting part 402 and a second limiting part 403. The fixing platform 401 is used to place the pose sensor 500. The pose sensor 500 is disposed outside the rotation axis 300. The first limiting part 402 is disposed on the fixing platform 401.

[0050] The first limiting part 402 abuts against the pose sensor 500 to restrict the circumferential movement of the pose sensor 500, and the second limiting part 403 abuts against the fixed base 100 to restrict the movement of the fixed frame 400.

[0051] The pose sensor 500 is calibrated by moving the mobile platform 200 to drive the rotation axis 300 to move.

[0052] This invention provides a calibration device for a sensor, such as... Figure 1 As shown, the calibration device includes a fixed base 100, a moving platform 200, and a fixed frame 400. First, the rotating shaft 300 is fixed on the moving platform 200, and the pose sensor 500 is placed outside the rotating shaft 300. By moving the moving platform 200 in the horizontal and vertical directions in the horizontal plane, the rotating shaft 300 is moved, thereby completing the calibration of the pose sensor 500. When calibrating the multiple displacement measurement channels of the pose sensor 500 using the calibration device of this invention, it is only necessary to place the pose sensor 500 on the fixed platform 401, and by moving the moving platform 200, the calibration of the multiple displacement measurement channels of the pose sensor 500 can be completed sequentially. This not only avoids the error caused by repeatedly installing the pose sensor 500 and improves the calibration accuracy of the pose sensor 500, but also significantly improves the calibration efficiency of the pose sensor 500. The calibration device of this invention will not damage the rotating shaft 300 during the calibration process and is simple to operate.

[0053] According to some preferred embodiments, it also includes a vibration isolation platform 600, on which both the fixed base 100 and the fixed frame 400 are fixed.

[0054] In this embodiment, such as Figure 2 As shown, by fixing the fixed base 100 and the fixed frame 400 to the vibration isolation platform 600, the vibration isolation platform 600 can offset the unnecessary vibrations generated by the working environment on the posture sensor 500 and the calibration device, thereby improving the calibration accuracy of the posture sensor 500.

[0055] According to some preferred embodiments, the first limiting part 402 is provided with a groove 4021, and the pose sensor 500 is provided with a protrusion 5001. The groove 4021 and the protrusion 5001 are inserted and engaged to restrict the circumferential movement of the pose sensor 500.

[0056] In this embodiment, such as Figure 2 and Figure 3As shown, the first limiting part 402 is disposed on the fixed platform 401. The first limiting part 402 has a reference surface a, and the pose sensor 500 has a reference surface b. The pose sensor 500 is placed on the fixed platform 401, and the reference surface b of the pose sensor 500 is fitted with the reference surface a of the first limiting part 402. Specifically, the reference surface a of the first limiting part 402 is provided with a groove 4021, and the reference surface b of the pose sensor 500 is provided with a protrusion 5001 that cooperates with the structure of the groove 4021. The pose sensor 500 restricts the circumferential movement of the pose sensor 500 through the insertion and cooperation of the structure of the protrusion 5001 and the structure of the groove 4021. The second limiting part 403 is located below the fixed platform 401 and is used to abut against the fixed base 100 to prevent the fixed frame 400 from moving. The second limiting part 403 has a reference surface c, and the moving platform 200 has a reference surface d. The reference surface c of the second limiting part 403 and the reference surface d of the moving platform 200 are in contact to restrict the movement of the fixed frame 400 and the moving platform 200, thereby further ensuring the stability of the calibration device.

[0057] According to some preferred embodiments, the fixed platform 401 is provided with a through hole for passing through the rotating shaft 300, the diameter of the through hole being larger than the diameter of the rotating shaft 300 and smaller than the diameter of the pose sensor 500.

[0058] In this embodiment, the rotating shaft 300 is cylindrical, such as... Figure 4 As shown, a through hole is provided on the fixed platform 401, and a pose sensor 500 is placed circumferentially in the through hole. The pose sensor 500 is composed of multiple eddy current displacement sensors located in multiple displacement measurement channels. Each eddy current displacement sensor is opposite to the circumferential surface of the rotation shaft 300 and perpendicular to the central axis of the rotation shaft 300. One end of the rotation shaft 300 is fixed on the moving platform 200, and the other end passes through the through hole on the fixed platform 401 so that the rotation shaft 300, the fixed platform 401, and the pose sensor 500 are on the same horizontal plane. At the same time, the diameter of the through hole is larger than the diameter of the rotation shaft 300 but smaller than the diameter of the pose sensor 500. This is more conducive to ensuring the stability of the pose sensor 500 on the fixed platform 401 and preventing calibration errors caused by the instability of the pose sensor 500.

[0059] This invention also provides a calibration method for a pose sensor 500, which is calibrated based on the calibration device described in any of the above embodiments, including:

[0060] The pose sensor is placed on the fixed platform 401;

[0061] The mobile platform 200 is moved to move the rotation axis 300, thereby calibrating the pose sensor 500.

[0062] In this embodiment, such as Figure 4 As shown, the pose sensor 500 is placed on the fixed platform 401, and the pose sensor 500 is fixed by the first limiting part 402 on the fixed platform 401 to prevent the pose sensor 500 from moving circumferentially, so that the rotation axis 300 is located at the center position of the pose sensor 500 measurement. The rotating axis 300 is driven to move laterally and / or longitudinally on the horizontal plane by the moving platform 200, thereby continuously changing the distance between the pose sensor 500 and the rotation axis 300, and thus completing the calibration of the pose sensor 500.

[0063] According to some preferred embodiments, moving the mobile platform 200 to move the rotation axis 300, thereby calibrating the pose sensor 500, includes:

[0064] Zero-position adjustment is performed on the pose sensor 500 and the calibration device;

[0065] Within the measurement range of the pose sensor 500, n preset displacement measurement values ​​P are taken. i The mobile platform 200 is moved to drive the rotating shaft 300 to n nominal displacement measurement points respectively, and the n measured displacement values ​​output by the pose sensor 500 are determined as D. i ;

[0066] Based on n preset displacement measurement values ​​P i and n measured displacement values ​​D i This allows for the calibration of the pose sensor 500.

[0067] In this embodiment, before calibrating the pose sensor 500, it is necessary to first perform zero-position adjustment on both the pose sensor 500 and the calibration device. The rotating shaft 300 is moved to the center position measured by the moving platform 200 (so that the distance between the rotating shaft 300 and each eddy current displacement sensor is equal), so that the center of the rotating shaft 300 coincides with the center of the pose sensor 500. At this time, the output value of the pose sensor 500 is zero, and the output displacement signal of the calibration device is also set to zero, thereby realizing the zero-position adjustment of the pose sensor 500 and the calibration device.

[0068] According to some preferred embodiments, the moving platform 200 is moved to drive the rotating shaft 300 to n nominal displacement measurement points respectively, and the n measured displacement values ​​output by the calibration device are respectively determined as D. i ,include:

[0069] With the center of the rotation axis 300 as the origin O, a plane rectangular coordinate system OXY is established on a horizontal plane perpendicular to the central axis of the rotation axis 300;

[0070] The fixed angle between each eddy current displacement sensor in the pose sensor 500 and the OX axis of the plane rectangular coordinate system is determined as α;

[0071] The moving platform 200 is moved a first preset distance along the OX axis of the Cartesian coordinate system, and the displacement platform is moved a second preset distance along the OY axis of the Cartesian coordinate system. The n measured displacement values ​​output by the pose sensor 500 are respectively determined as D. i .

[0072] In this embodiment, such as Figure 5 As shown, with the center of the rotation axis 300 as the origin O, a Cartesian coordinate system OXY is established on a horizontal plane perpendicular to the central axis of the rotation axis 300 (i.e., on the horizontal plane of the fixed platform 401). Since the installation positions of the multiple eddy current displacement sensors in the pose sensor 500 are fixed, the angle between each eddy current displacement sensor and the OX axis in the Cartesian coordinate system can be determined and denoted as α, where 0 ≤ α ≤ 360°. Furthermore, the displacement measurement range of the pose sensor 500 is known. Then, within the measurement range of the pose sensor 500 (-S0 to +S0), n preset displacement measurement values ​​P are taken at equal intervals. i The mobile platform 200 is moved a preset distance along the OX axis and OY axis in the horizontal plane of the Cartesian coordinate system, respectively. At this time, the pose sensor 500 outputs n displacement measurement values ​​D. i .

[0073] According to some preferred embodiments, the first distance is P. i cosα, the second distance is P i sinα.

[0074] For example, such as Figure 5 As shown, taking the eddy current displacement sensor 5002 in the pose sensor 500 as an example, the angle between the eddy current displacement sensor 5002 and the OX axis of the Cartesian coordinate system is α. When calibrating it, the measurement range of the eddy current displacement sensor 5002 is known to be S0. First, n equally spaced displacement measurement values ​​P are taken within the displacement measurement range S0 of the eddy current displacement sensor 5002. i , i = 1: n, then move the mobile platform 200 along the OX axis and OY axis of the Cartesian coordinate system respectively. i cosα and P i sinα, at this time the coordinate point of the rotation axis 300 in the plane rectangular coordinate system is (P icosα, P i sinα), and correspondingly record the n displacement measurement values ​​D output by the moving eddy current displacement sensor 5002. i , i = 1: n, through the known preset displacement measurement value P i i = 1:n and the measured displacement value D i i = 1:n, thereby achieving the calibration of the eddy current displacement sensor 5002; each eddy current displacement sensor in the pose sensor 500 is calibrated sequentially according to the above method, thereby completing the calibration of the pose sensor 500.

[0075] According to some preferred embodiments, the step of using n preset displacement measurement values ​​P i and n measured displacement values ​​D i The pose sensor 500 is calibrated, including:

[0076] Based on the n preset displacement measurement values ​​P i and n measured displacement values ​​D i Calculate the scaling factor K and zero position Z of each eddy current displacement sensor in the pose sensor 500;

[0077] The scaling factor K and zero point Z of each eddy current sensor in the pose sensor 500 are calculated using the following formulas:

[0078]

[0079]

[0080] In the formula, P i D is the preset displacement measurement value. i The measured displacement value is n, which is a positive integer, and S0 is the measurement range of the pose sensor 500.

[0081] According to some preferred embodiments, the nonlinearity L of each eddy current sensor in the pose sensor 500 is the fitted displacement, which is calculated by the following formula:

[0082]

[0083] In the formula, P i D is the preset measurement value. i The measured displacement value is n, which is a positive integer, and S0 is the measurement range of the pose sensor 500.

[0084] In this invention, the pose sensor 500 is placed in the calibration device. After completing one calibration product mounting, the parameter calibration of the eddy current displacement sensor in multiple measurement directions can be completed simply by moving the moving platform 200. The calibration device and calibration method in this invention can not only realize the calibration of measurement channels in multiple directions within two degrees of freedom, but also eliminate the calibration error caused by multiple mountings in the calibration system of the prior art, improve the calibration accuracy of the pose sensor 500, and improve the calibration efficiency of the pose sensor 500.

[0085] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calibration device for a pose sensor, characterized in that, include: Fixed base; A mobile platform is fixed on the fixed base. The mobile platform is used to fix the rotating shaft and can move along the horizontal and vertical directions of the horizontal plane. The fixing frame includes a fixing platform, a first limiting part and a second limiting part. The fixing platform is used to place the pose sensor, which is disposed outside the rotation axis. The first limiting part is disposed on the fixing platform. The first limiting part abuts against the pose sensor to restrict the circumferential movement of the pose sensor, and the second limiting part abuts against the fixed base to restrict the movement of the fixed frame; The pose sensor is calibrated by moving the mobile platform to drive the rotation axis to move. The method for calibrating the pose sensor using a calibration device is as follows: Place the pose sensor on the fixed platform; The pose sensor and the calibration device are zero-position adjusted; Within the measurement range of the pose sensor, n preset displacement measurement values ​​P are taken. i The moving platform is moved to drive the rotating axis to n nominal displacement measurement points respectively, and the n measured displacement values ​​output by the pose sensor are determined as D. i ; Based on n preset displacement measurement values ​​P i and n measured displacement values ​​D i This allows for the calibration of the pose sensor. The moving platform is moved to drive the rotating shaft to n nominal displacement measurement points respectively, and the n measured displacement values ​​output by the calibration device are respectively determined as D. i ,include: With the center of the rotation axis as the origin O, establish a plane rectangular coordinate system OXY on a horizontal plane perpendicular to the central axis of the rotation axis; The fixed angle between each eddy current displacement sensor in the pose sensor and the OX axis of the plane rectangular coordinate system is determined as α; The mobile platform is moved a first distance along the OX axis of the Cartesian coordinate system, and a second distance along the OY axis of the Cartesian coordinate system. The n measured displacement values ​​output by the pose sensor are respectively determined as D. i .

2. The calibration device according to claim 1, characterized in that, It also includes a vibration isolation platform, and the fixed base and the fixed frame are both fixed on the vibration isolation platform.

3. The calibration device according to claim 1, characterized in that, The first limiting part is provided with a groove, and the pose sensor is provided with a protrusion. The groove and the protrusion are inserted and engaged to limit the circumferential movement of the pose sensor.

4. The calibration device according to claim 1, characterized in that, The fixed platform is provided with a through hole for the rotating shaft to pass through, the diameter of which is larger than the diameter of the rotating shaft and smaller than the diameter of the pose sensor.

5. The calibration device according to claim 1, characterized in that, The first distance is P i cosα, the second distance is P i sinα.

6. The calibration device according to claim 1, characterized in that, The method is based on n preset displacement measurement values ​​P i and n measured displacement values ​​D i The pose sensor is calibrated, including: Based on the n preset displacement measurement values ​​P i and n measured displacement values ​​D i Calculate the scaling factor K and zero position Z of each eddy current displacement sensor in the pose sensor; The scaling factor K and zero point Z of each eddy current sensor in the pose sensor are calculated using the following formulas: In the formula, P i D is the preset displacement measurement value. i The measured displacement value is n, where n is a positive integer.

7. The calibration device according to claim 6, characterized in that, The nonlinearity L of each eddy current sensor in the pose sensor is calculated using the following formula: In the formula, S0 is the measurement range of the pose sensor.

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