WO2022016721A1 - Precise calibration apparatus and method for magnetorheological polishing device - Google Patents

Abstract

Provided are a precise calibration apparatus and method for a magnetorheological polishing device. The magnetorheological polishing device comprises a polishing wheel (3) and a support (7) which is used to install the polishing wheel (3). The precise calibration apparatus comprises: an arc-shaped bracket (5), a sensor (4), a signal acquisition circuit (8), an industrial control upper computer (9) and a motion control circuit (10); the apparatus can implement an automated rapid calibration process, ensuring that the polishing clearance stays within a permitted error range when the magnetorheological polishing device processes the surfaces of various optical elements (2), so as to effectively control a removal function, reduce or eliminate low-frequency and middle-frequency errors introduced by the insufficient trajectory precision of a mechanic arm (1) within a profile residual error after processing, thus increasing the process precision of the mechanic arm (1)-based magnetorheological polishing device.

Description

A precision calibration device and method for magnetorheological polishing equipment

This application claims the priority of the Chinese patent application filed on July 21, 2020 with the application number 202010704882.5 and the invention titled "A device and method for precision calibration of magnetorheological polishing equipment", the entire contents of which are Incorporated herein by reference.

technical field

The invention relates to the technical field of magnetorheological polishing equipment, in particular to a precision calibration device and method for magnetorheological polishing equipment.

Background technique

The moving carrier of the existing magnetorheological polishing equipment is mainly based on the multi-axis linkage CNC machining center. With the development of science and technology, the magnetorheological polishing module can be integrated on the manipulator, that is, the manipulator is used as the motion carrier of the magnetorheological polishing equipment, which has the advantages of large motion speed and acceleration, flexible motion and high processing efficiency. The same processing range, the cost is much lower than the multi-axis CNC machining center, and the floor area is small.

However, compared with multi-axis CNC machine tools, the robot arm has the disadvantage of low motion trajectory accuracy, that is, the end of the robot arm cannot accurately execute the preset trajectory in the optical processing process, and the trajectory accuracy error often reaches the sub-millimeter level. The accuracy of the machine tool motion trajectory is often an order of magnitude higher than that of the robotic arm. The reason for the low accuracy of the motion trajectory is closely related to the multi-joint series structure of the manipulator. The low precision of the motion trajectory leads to unstable or uncontrollable changes in the "polishing gap" between the magnetorheological polishing wheel and the workpiece surface, which in turn leads to unstable or unpredictable changes in the removal function, which is ultimately manifested as robotic arm-based The machining accuracy of magnetorheological polishing equipment is limited, and there are typical low-frequency and medium-frequency errors introduced by the robotic arm in the surface shape residual after machining.

Therefore, how to keep the polishing gap within the allowable error range when the magnetorheological polishing equipment processes various optical elements is a technical problem that those skilled in the art need to solve urgently.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a precision calibration device for magnetorheological polishing equipment, which can effectively improve the machining accuracy of the magnetorheological polishing equipment, and another object is to provide a precision calibration method for magnetorheological polishing equipment.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

A precision calibration device for magnetorheological polishing equipment, the magnetorheological polishing equipment includes a polishing wheel and a support for installing the polishing wheel, including: an arc bracket, a sensor, a signal acquisition module, an industrial control host computer and a motion control module;

The arc-shaped bracket is detachably connected to the support, the arc-shaped bracket has an arc-shaped surface that is mutually abutted with the polishing wheel, and the sensor is fixed on the arc-shaped bracket for detecting the polishing gap. ;

The signal acquisition module is connected to the sensor, the industrial control host computer is respectively connected to the signal acquisition module and the motion control module, the motion control module is connected to the control system of the magnetorheological polishing equipment, the industrial control The host computer is used to send instructions to the signal acquisition module and the motion control module, the signal acquisition module is used to control the sensor to collect data, and the motion control module is used to send instructions to the control system to make The polishing wheel moves on a preset processing track.

Preferably, the sensor is a displacement sensor or a pressure sensor.

Preferably, the arc-shaped support is provided with a through hole, the effective working hole of the sensor coincides with the through hole, and the center of the effective working hole of the sensor coincides with the apex of the spherical cap of the polishing wheel.

Preferably, the arc-shaped bracket is provided with an adjusting frame, the adjusting frame is provided with a bar-shaped hole for adjusting its upper and lower heights, and the adjusting frame is fixed on the on the stand.

Preferably, the adjusting bracket is provided with two sets of the strip-shaped holes arranged in parallel with each other.

A method for calibrating the precision of magnetorheological polishing equipment, comprising the following steps:

Install the optical components to be processed on the magnetorheological polishing equipment, and align the workpiece coordinate system with the processing coordinate system;

Install the arc support of the precision calibration device on the support of the polishing wheel;

Controlling the sensor to collect the displacement value between the sensor and the optical element to be processed, and controlling the polishing wheel to move with a preset processing track;

obtaining the error value between the displacement value and the preset value;

Determine whether the error value meets the accuracy requirements;

If so, the error value is compensated to the preset processing track of the magnetorheological polishing equipment;

If not, correct the preset machining trajectory according to the error value;

The error value between the displacement value and the preset value is repeatedly acquired according to the corrected preset processing trajectory.

Preferably, the steps of controlling the sensor to collect the displacement value between the sensor and the optical element to be processed, and simultaneously controlling the polishing wheel to move with a preset processing track are as follows:

The industrial control host computer sends instructions to the signal acquisition circuit and the motion control circuit, the signal acquisition circuit controls the sensor to collect data, and the motion control circuit issues instructions to the control system of the magnetorheological polishing equipment, so that the polishing The wheel moves on a preset machining path.

Preferably, the step of acquiring the error value between the displacement value and the preset value is specifically:

The data collected by the sensor is processed in the industrial control host computer, and each collected displacement value is compared with a preset value to obtain an error value.

Preferably, the error value includes a low frequency error, an intermediate frequency error and a high frequency error.

Compared with the prior art, the above technical solution has the following advantages:

The accuracy calibration device of the magnetorheological polishing equipment provided by the present invention, when the accuracy calibration needs to be performed, the arc-shaped support provided with the sensor is installed on the support. The installation method of the displacement sensor of the present invention ensures that the distance between the polishing wheel and the optical element to be processed can be very short during precision calibration, and the distance corresponds to the polishing gap of the order of millimeters during actual processing, which can effectively ensure the calibration accuracy and Accuracy in actual use. After the calibration is completed, the arc-shaped bracket carrying the sensor can be disassembled from the support as a whole, and then the actual optical element can be processed using the magnetorheological polishing equipment.

The method for calibrating the accuracy of magnetorheological polishing equipment provided by the present invention can effectively ensure that the measured data corresponds to the motion position of the manipulator because the data collection by the accuracy calibrating device is synchronized with the motion of the manipulator, and the accuracy of the data is guaranteed. Effectiveness; all frequency band errors affecting the "polishing gap" can be measured, and effective compensation can be made to the low frequency, intermediate frequency and high frequency of the system error part, thereby improving the accuracy of the equipment; the direct measurement error can be converted into actual processing time Therefore, it is easier to obtain the actual machining code with significantly improved motion trajectory accuracy after error compensation.

Description of drawings

In order to explain the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are of the present invention. For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic structural diagram of a precision calibration device of a magnetorheological polishing apparatus provided by a specific embodiment of the present invention;

Fig. 2 is the enlarged view of A area in Fig. 1;

Fig. 3 is the schematic diagram that the precision calibration device is not installed in Fig. 2;

Fig. 4 is the schematic diagram observed along the Y positive direction in Fig. 2;

FIG. 5 is a schematic diagram viewed along the positive Z direction in FIG. 2 .

The reference numbers are as follows:

1 is the mechanical arm, 2 is the optical element, 3 is the polishing wheel, 4 is the sensor, 5 is the arc bracket, 6 is the adjustment bracket, 7 is the support, 8 is the signal acquisition circuit, 9 is the industrial control host computer, and 10 is the motion For the control circuit, 11 is a cable, and 12 is a through hole.

detailed description

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the following description, specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar promotions without departing from the connotation of the present invention. Accordingly, the present invention is not limited by the specific embodiments disclosed below.

Please refer to FIGS. 1 to 5. FIG. 1 is a schematic structural diagram of a precision calibration device for a magnetorheological polishing apparatus provided by a specific embodiment of the present invention; FIG. 2 is an enlarged view of area A in FIG. 1; FIG. 3 Fig. 2 is a schematic diagram without the precision calibration device installed; Fig. 4 is a schematic diagram viewed along the positive Y direction in Fig. 2; Fig. 5 is a schematic diagram viewed along the positive Z direction in Fig. 2 .

A specific embodiment of the present invention provides a precision calibration device for magnetorheological polishing equipment. The magnetorheological polishing equipment includes a polishing wheel and a support for installing the polishing wheel, including: an arc support, a sensor, a signal acquisition module, industrial control host computer and motion control module. The arc-shaped bracket is provided with an arc-shaped surface, and the sensor is fixed on the arc-shaped bracket. The sensor is preferably a displacement sensor, or a pressure sensor, to measure the contact force to determine the size of the polishing gap. The signal acquisition module can be connected with the sensor through the signal and power cable. The industrial control host computer can be connected with the signal acquisition module and the motion control module respectively through the signal and power cable. The motion control module can be controlled by the magnetorheological polishing equipment through the signal and power cable. system connection. When precision calibration is required, the arc-shaped bracket provided with the sensor is installed on the support, and the surface of the arc-shaped bracket in contact with the polishing wheel is set as an arc-shaped surface, and the arc-shaped surface is consistent with the radius of curvature of the polishing wheel. The arc-shaped bracket is provided with a through hole, the effective working hole of the sensor coincides with the through hole, and the center of the effective working hole of the sensor coincides with the vertex of the spherical cap of the polishing wheel. In order to ensure the positional coincidence relationship, it can be done through the following aspects: a. Ensure as much as possible in the mechanical design, at the same time use the arc bracket to fully fit the polishing wheel, and install the sensor in a specific position; b. Use a three-coordinate or laser tracker, etc. The coordinate measuring equipment checks the magnetorheological polishing module after installing the calibration device; c performs effective error compensation. The installation method of the displacement sensor of the present invention ensures that the distance between the polishing wheel and the optical element to be processed can be very short during precision calibration, and the distance corresponds to the polishing gap of the order of millimeters during actual processing, which can effectively ensure the calibration accuracy and Accuracy in actual use. It can also be understood that the position and attitude of each joint of the manipulator arm in the precision calibration state of the present invention and the actual processing state are consistent, which can effectively improve the precision of the polishing gap during actual processing. After the calibration is completed, the entire arc-shaped bracket carrying the sensor can be disassembled from the support, that is, once calibrated once, the positional relationship of each sub-component does not need to be calibrated again when it is used again. When the accuracy calibration is performed, the industrial control host computer sends instructions to the signal acquisition module and the motion control module, the signal acquisition module controls the sensor to collect data, and the motion control module sends instructions to the control system to make the polishing wheel move with the preset processing track. The data collected by the sensor is processed in the industrial control host computer, and each displacement value collected is compared with the preset value to obtain an error value, and it is judged whether the error value meets the accuracy requirements. The preset processing trajectory is compensated, and the error value is continuously obtained until the accuracy requirements are met. When the error value meets the accuracy requirements, the error value is compensated to the preset processing trajectory of the magnetorheological polishing equipment, and the accuracy calibration operation can be completed. , after removing the calibration device, the actual optical components can be processed using magnetorheological polishing equipment.

Further, the arc-shaped bracket is provided with an adjustment frame, and the adjustment frame is provided with a bar-shaped hole, wherein preferably two parallel bar-shaped holes are arranged, and the adjustment frame is fixed on the support through the fastener through the bar-shaped hole, The height position of the adjusting frame can be easily adjusted through the strip hole, and then the height position of the sensor can be adjusted.

A specific embodiment of the present invention also provides a method for calibrating the accuracy of magnetorheological polishing equipment, comprising the following steps:

Step 1: The workpiece is pre-aligned, and the optical element to be processed is installed on the magnetorheological polishing equipment. The optical element can be a plane, a spherical surface, a spherical surface, a free-form surface, etc. Various materials such as SiC ceramics and alloys can be mirrors or lenses. The workpiece coordinate system can be aligned with the machining coordinate system using existing methods.

Step 2: Install the accuracy calibration device, install the arc-shaped bracket of the accuracy calibration device on the support of the polishing wheel, specifically, assemble the accuracy calibration device provided in the above embodiment first. When designing, try to make the sensor The center of the effective working hole is located at the vertex position of the spherical cap of the magnetorheological polishing wheel; after the hardware design is completed, the adjustment amount is reserved, and the space coordinate measuring device such as high-precision three-coordinate or high-precision laser tracker is used for the first use. Check, once the check is completed, the sensor and the arc bracket are no longer disassembled, and their relative positions are fixed. The position of the effective working hole does not need to be checked again.

Step 3: Processing trajectory planning, determine a reasonable processing trajectory according to the geometric parameters of the optical element to be processed, the initial surface shape error, etc. and other complex trajectories.

Step 4: The robot arm executable code. In this step, the processing trajectory is converted into the robot arm executable code by combining the geometric parameters of the optical element to be processed and the motion axis parameters of the robot magnetorheological polishing equipment. The converted code guarantees two points: 1. Without considering the motion accuracy of the robotic arm, ensure that the distance between the sensor installed on the magnetorheological polishing wheel and the surface of the optical element to be processed is as close as possible, that is, within the effective working range, and Keep the distance consistent in different areas of the full aperture of the optical element, which corresponds to the concept of "polishing gap"; 2. Set the speed between the dwell points on the processing track, which can be between all dwell points The speed is the same, that is, the robot arm drives the magnetorheological polishing module to move at a uniform speed, or the speed between the dwell points is different, or it can be the speed converted from the actual dwell time calculated according to the surface error of the actual optical element. Among them, the movement speed of the equipment in the code executed by the robotic arm is adjustable, which ensures that the calibration process can shorten the time and reduce the occupation of the actual processing cycle.

Step 5: The robotic arm is turned on and ready to run. The industrial control host computer is used to automatically import the executable code in Step 4 into the motion control module of the robotic arm, and the robotic arm is turned on and adjusted to the motion ready state.

Step 6: Set the parameters of the precision calibration device, set the parameters of the sensor of the precision calibration device, and set the sampling frequency, working range, dynamic range, etc. in the industrial control host computer.

Step 7: The accuracy calibration device is turned on and ready to run, and the signal acquisition circuit and sensors in the accuracy calibration device are turned on and adjusted to a state of being run.

Step 8: The precision calibration device and the magnetorheological polishing equipment run synchronously, and the industrial control host computer is used to send instructions to the signal acquisition circuit and the motion control circuit respectively. The signal acquisition circuit controls the displacement sensor to start data acquisition, and the motion control circuit gives the robotic arm control system. Command the robot arm to start moving according to the code in step 4. That is, in this step, the synchronizing operation of the calibration device and the robot magnetorheological equipment should be realized, and the two should be guaranteed to be performed under the same clock. Because the precision calibration device synchronizes the data collection and the movement of the robot arm, it can effectively ensure that the measured data corresponds to the movement position of the robot arm, and the validity of the data is ensured.

Step 9: data processing, the data collected by the signal collection circuit is processed in the industrial control host computer, and each collected displacement data is compared with the set theoretical displacement value to obtain an error value. Various types of errors are extracted from the error value, including low frequency error, intermediate frequency error and high frequency error. The low-frequency error comes from misalignment: a. The low-order error caused by the pre-alignment of the workpiece in step 1; b. The low-order error caused by the misalignment between the effective working hole of the displacement sensor and the apex of the spherical crown of the magnetorheological polishing wheel in step 2, These low-frequency errors mainly exist in the form of tilt, defocus, astigmatism and coma in the collected data. The intermediate frequency error is mainly caused by the movement of the manipulator. The high-frequency error is mainly caused by the vibration of the robot magnetorheological polishing equipment in motion. The low frequency error, intermediate frequency error and part of the high frequency error (systematic error part) are extracted.

Step 10: Error compensation, performing error compensation on the low-frequency error, intermediate-frequency error and part of the high-frequency error extracted in step 9, that is, taking the measured error into account in the processing track of step 3.

Step 11: The manipulator can execute code correction. According to the error compensation in step 10, combined with the geometric parameters of the optical element and the motion axis parameters of the robot magnetorheological polishing equipment, the processing trajectory is converted into the manipulator executable code again.

Step 12: When the robotic arm is ready to run, use the industrial control host computer to automatically import the code in Step 11 into the motion control system of the robotic arm, and adjust the robotic arm to the ready-to-run state.

Step 13: The parameter setting of the calibration device. The parameter settings of the sampling frequency, working range and dynamic range can be optimized in the industrial control host computer 9 according to the measurement results in step 10, or do not need to be set again.

Step 14: The precision calibration device is ready to run. In this step, the industrial control host computer is used to adjust the signal acquisition circuit and the displacement sensor to the standby state.

Step 15: Synchronous operation. This step is the same as step 8. The industrial control host computer 9 is used to issue instructions to the signal acquisition circuit 8 and the motion control circuit 10 respectively. The signal acquisition electronic control 8 controls the displacement sensor 4 to start data acquisition, while the motion control circuit 10. Send an instruction to the robotic arm control system to start moving the robotic arm according to the code in step 11. That is, in this step, the synchronizing operation of the calibration device and the robot magnetorheological equipment should be realized, and the two should be guaranteed to be performed under the same clock. However, the executable code of the robot arm running in this step is the code after the error compensation in step 11.

Step 16: data processing, the data collected by the signal collection circuit 8 is processed again in the industrial control host computer 9, and the theoretical values set by the collected displacement data are compared to obtain an error value.

Step 17: Judging whether the error value satisfies the accuracy condition, in this step, the error data in step 16 is compared with the required accuracy. The main comparison here is the systematic error part of low frequency error, intermediate frequency error and high frequency error, whether it has reached the requirements of robot magnetorheological polishing equipment, which is determined by the requirements of the corresponding optical processing technology for "polishing gap".

If the required accuracy conditions are not met, the preset machining trajectory is corrected according to the error value; according to the corrected preset machining trajectory, the error value between the displacement value and the preset value is repeatedly obtained, that is, steps 10 to 10 are repeated. 16. Among them, the industrial control host computer is used to automatically control the calibration device and the manipulator. After the parameters are preset, the key steps 10 to 17 of the error calibration are automated processes without manual participation.

If the required accuracy conditions are met, proceed to the next step.

Step 18: Error compensation processing code. When it is judged in Step 17 that the accuracy condition is met, this step is performed to compensate the error value to the preset processing track of the magnetorheological polishing equipment. In this step, various types of errors during the error compensation in step 10 are accumulated and compensated into the machining code, which is synthesized from the machining trajectory and the dwell time calculated according to the actual surface shape error. It should be noted here that the displacement values measured in steps 9 and 16 are not the real "polishing gap", but the distance between the displacement sensor 4 installed on the magnetorheological polishing wheel mentioned in step 4 and the surface of the optical element being processed distance, but this displacement value corresponds to the "polishing gap". Therefore, when performing code conversion after error compensation in this step, the difference between the calibrated displacement value and the "polishing gap" should be considered, and the linear difference between the two should be eliminated, and then the truly compensated can guarantee " Polishing Gap" constant machining code.

Step 19: Remove the precision calibration device. After completing Step 18, before actually processing the optical element, remove the precision calibration device as a whole for subsequent use.

Step 20: The actual workpiece is processed. After all the above calibrations are completed, the robot magnetorheological polishing equipment can be used to process the actual optical components.

To sum up, the accuracy calibration device and method for magnetorheological polishing equipment provided by the present invention can realize an automatic and rapid calibration process, and ensure that when the magnetorheological polishing equipment processes the surfaces of various optical workpieces, the polishing gap is kept within the allowable range. Within the error range, the removal function can be effectively controlled to reduce or eliminate the low-frequency and intermediate-frequency errors caused by the insufficient track accuracy of the residual robot arm after processing, and improve the machining accuracy of the robot-based magnetorheological polishing equipment. It has at least the following advantages:

1. The range of error frequency bands that can be calibrated is wide, all frequency band errors affecting the "polishing gap" can be measured, and the low frequency, medium frequency and high frequency of the system error part can be effectively compensated, thereby improving the processing accuracy of the equipment.

2. Strong applicability: optical components can be plane, spherical, aspherical, free-form surface, etc., or convex or concave, or optical glass, SiC ceramics, alloys and other materials; the calibration equipment is not only Limited to robotic magnetorheological polishing equipment, other equipment based on robotic arms or equipment based on multi-axis linkage machine tools can be directly adopted or used for reference to the content of the present invention for accuracy calibration and improvement

3. The calibration accuracy of the present invention is high, and the accuracy of the existing displacement sensors can generally reach the order of micrometers. On this basis, the present invention performs error compensation through repeated iterations, which can effectively improve the accuracy; The displacement corresponding to the final demand "polishing gap" has a linear relationship, which can also ensure the calibration accuracy of the present invention; the movement trajectory of the robot arm in the calibration process is consistent with the movement trajectory during actual processing, ensuring the calibration and The accuracy of actual machining is consistent.

4. Improve the accuracy of the actual processing of optical components by the equipment: improve the accuracy of the motion trajectory of the robotic arm itself, ensure the constant "polishing gap", and then ensure the stability of the magnetorheological removal function, which is the most important improvement in processing. On the other hand, the calibration step of the present invention also compensates for errors such as workpiece alignment, and further improves the actual machining accuracy.

5. High calibration efficiency: The calibration hardware is quick to install and disassemble; the running speed in the code of the robotic arm can be adjusted during calibration; the more automated error measurement and iterative compensation process.

6. Wide range of applicable structures. It is not only suitable for the workpiece (mirror 2) on the bottom, but also the tool (magnetorheological polishing module and robot arm 3) on the top. It is also applicable to other forms, such as the position-dependent replacement of the mirror 2 with the magnetorheological polishing module (including the magnetorheological polishing wheel) in Figure 1, that is, the mirror is grasped by the robot arm above and the magnetorheological polishing module is below. , that is, the form where the workpiece is on the top and the tool is on the bottom. The structure of the workpiece on the bottom and the tool on the top or the workpiece on the top and the tool on the bottom can also be placed horizontally. All forms conforming to the principle of the relative relationship between workpiece and tool positions in the present invention are applicable to the present invention.

In addition, the present invention ensures the stability of the magnetorheological polishing removal function by ensuring that the "polishing gap" is constant. It can also be replaced by ensuring a controllable change in the "polishing gap" to ensure a controllable change in the magnetorheological polishing removal function. High-precision machining of optical components is also possible based on this controllable variation.

It should also 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 those entities or operations There is no such actual relationship or order between them. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A precision calibration device for magnetorheological polishing equipment, the magnetorheological polishing equipment includes a polishing wheel and a support for installing the polishing wheel, and is characterized in that it includes: an arc-shaped bracket, a sensor, a signal acquisition module, an industrial control upper position machine and motion control modules;

   The arc-shaped bracket is detachably connected to the support, the arc-shaped bracket has an arc-shaped surface that is mutually abutted with the polishing wheel, and the sensor is fixed on the arc-shaped bracket for detecting the polishing gap. ;

   The signal acquisition module is connected to the sensor, the industrial control host computer is respectively connected to the signal acquisition module and the motion control module, the motion control module is connected to the control system of the magnetorheological polishing equipment, the industrial control The host computer is used to send instructions to the signal acquisition module and the motion control module, the signal acquisition module is used to control the sensor to collect data, and the motion control module is used to send instructions to the control system to make The polishing wheel moves on a preset processing track.
2. The precision calibration device according to claim 1, wherein the sensor is a displacement sensor or a pressure sensor.
3. The precision calibration device according to claim 1, wherein a through hole is provided on the arc-shaped support, the effective working hole of the sensor coincides with the through hole, and the center of the effective working hole of the sensor Coincide with the apex of the spherical cap of the polishing wheel.
4. The precision calibration device according to claim 1, characterized in that, an adjusting frame is provided on the arc-shaped bracket, and the adjusting frame is provided with a bar-shaped hole for adjusting its upper and lower heights, and the adjusting frame is tightened by tightening The piece is fixed on the support through the strip hole.
5. The precision calibration device according to claim 4, wherein the adjustment bracket is provided with two groups of the strip holes arranged in parallel with each other.
6. A method for calibrating the accuracy of magnetorheological polishing equipment, comprising the following steps:

   Install the optical components to be processed on the magnetorheological polishing equipment, and align the workpiece coordinate system with the processing coordinate system;

   Install the arc support of the precision calibration device on the support of the polishing wheel;

   Controlling the sensor to collect the displacement value between the sensor and the optical element to be processed, and controlling the polishing wheel to move with a preset processing track;

   obtaining the error value between the displacement value and the preset value;

   Determine whether the error value meets the accuracy requirements;

   If so, the error value is compensated to the preset processing track of the magnetorheological polishing equipment;

   If not, correct the preset machining trajectory according to the error value;

   The error value between the displacement value and the preset value is repeatedly acquired according to the corrected preset processing trajectory.
7. The accuracy calibration method according to claim 6, wherein the steps of controlling the sensor to collect the displacement value between the sensor and the optical element to be processed, and simultaneously controlling the polishing wheel to move with a preset processing track are concrete for:

   The industrial control host computer sends instructions to the signal acquisition circuit and the motion control circuit, the signal acquisition circuit controls the sensor to collect data, and the motion control circuit issues instructions to the control system of the magnetorheological polishing equipment, so that the polishing The wheel moves on a preset machining path.
8. The precision calibration method according to claim 7, wherein the step of obtaining the error value between the displacement value and the preset value is specifically:

   The data collected by the sensor is processed in the industrial control host computer, and each collected displacement value is compared with a preset value to obtain an error value.
9. The precision calibration method according to claim 8, wherein the error value includes a low frequency error, an intermediate frequency error and a high frequency error.

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