Magnetorheological polishing equipment and method based on sensor-adjusted electromagnet

Abstract

The present invention relates to the field of optical processing technology, and in particular to a magnetorheological polishing device and method based on sensor-regulated electromagnets. The device comprises a laser tracker, a control unit, a robot, a magnetorheological processing module, and a sensor module. The magnetorheological processing module is arranged at the end of the robot, and the robot drives the magnetorheological processing module to process an optical element. The sensor module is arranged on the magnetorheological processing module. The laser tracker cooperates with a target ball to measure the spatial coordinates of the sensor module and the working points of the polishing wheel in the magnetorheological processing module. In the method, the laser tracker and the sensor module cooperate to measure the real-time changes in the robot's posture and the position of the magnetorheological processing module during the processing, and the position or magnetic field strength of the electromagnet in the magnetorheological processing module is regulated in real time, thereby achieving real-time constant control of the removal function of the optical element.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical processing, and in particular relates to a magnetorheological polishing device and method based on sensor-adjusted electromagnets. Background Art

[0002] Magnetorheological finishing (MRF) is an advanced optical manufacturing technology that has developed in recent years. It boasts numerous advantages, including stable removal function, controllable edge effects, minimal subsurface damage, no photocopying, strong reshaping capabilities, and high machining accuracy. Consequently, MRF has garnered widespread attention in high-precision optical processing. Existing MRF processes primarily integrate MRF modules onto CNC machine tools. However, CNC machine tools have several limitations (such as low degrees of freedom, large footprint, and high cost), which limit the deviation of aspheric surfaces and make precise pose control along the surface normal difficult.

[0003] To address these shortcomings of CNC machine tools, researchers have introduced six-degree-of-freedom (6DOF) industrial robots into the field of optical processing in recent years. These robots offer advantages such as high degrees of freedom, a small footprint, a large processing range, and low cost, which offset the shortcomings of CNC machine tools. Therefore, integrating a magnetorheological polishing module into an industrial robot can theoretically achieve high-precision processing of large-diameter, complex-curved optical components. However, due to the influence of factors such as machining, assembly, load, trajectory planning, and reduction ratio generated during the integration of the robot and the magnetorheological polishing module, the robot's end-of-process execution accuracy is low, and the polishing gap varies significantly during processing. Furthermore, magnetorheological polishing technology is an optical processing technology with a high degree of determinism in the removal function, which places high demands on the polishing gap variation during the polishing process. The polishing gap variation of a typical magnetorheological CNC machining center is in the tens of microns (PV < 0.1mm), while the trajectory accuracy of common commercial robots is generally in the sub-millimeter to millimeter range. This results in significant variations in the polishing gap during processing. Large changes in the polishing gap will lead to a decrease in the certainty of the removal function, affecting the final processing accuracy. Therefore, the motion accuracy of currently commercial large-scale six-degree-of-freedom industrial robots often cannot meet the requirements of magnetorheological polishing technology for changes in the removal function during high-precision polishing.

[0004] To address the issue of low robot motion precision, real-time control solutions for constant-force grinding and polishing have become a research hotspot. Force-position control has become a common method for controlling constant-force grinding and polishing in robots. A common application involves placing a force sensor between the machining tool and the robot. The force sensor is first calibrated with gravity to ensure accurate measurement. The position error is calculated by measuring force changes. This position error is then compensated for using the robot itself or other motion compensation mechanisms to achieve constant-force control. High-efficiency machining of large-aperture optical components requires a magnetorheological machining module with large polishing wheels, which typically weigh hundreds of kilograms. However, for a magnetorheological machining module weighing hundreds of kilograms, the force variation caused by the robot's position error is only tens of Newtons. High-precision machining requires maintaining a constant force of a few Newtons or even a fraction of a Newton. This requires measurement equipment such as force sensors to achieve an absolute accuracy of one part per ten thousand. Furthermore, the force sensor must be able to operate at varying speeds and positions. Force sensors that meet these requirements are often extremely expensive, significantly increasing the cost of the equipment. Summary of the Invention

[0005] In view of this, the present invention aims to provide a magnetorheological polishing device and method based on sensor-adjusted electromagnets, using a laser tracker and a sensor module to measure the real-time changes in the robot's posture and the position of the magnetorheological processing module during processing, and to adjust the position or magnetic field strength of the electromagnet in the magnetorheological processing module in real time, thereby achieving real-time constant control of the removal function of the optical element to be processed.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0007] A magnetorheological polishing device based on sensor-adjusted electromagnets includes a laser tracker, a control unit, a robot, a magnetorheological processing module, and a sensor module. The magnetorheological processing module is disposed at the free end of the robot, and the robot drives the magnetorheological processing module to process optical components. The sensor module is disposed on the magnetorheological processing module. The laser tracker cooperates with a target ball disposed on the magnetorheological processing module to measure the spatial coordinates of the sensor module and the working point of the polishing wheel in the magnetorheological processing module.

[0008] The interior of the control unit includes:

[0009] The coordinate relationship module integrates and calculates the spatial coordinates collected by the laser tracker and the position information collected by the sensor module, and outputs the integrated position information;

[0010] A conversion relationship module is configured to fit the magnetic field strength of the electromagnet in the magnetorheological processing module with the polishing gap of the polishing wheel to obtain a first conversion relationship, and to fit the electromagnet position of the electromagnet with the polishing gap to obtain a second conversion relationship;

[0011] The real-time control module adjusts the magnetic field strength according to the integrated position information and the first conversion relationship, and / or adjusts the position of the electromagnet according to the integrated position information and the second conversion relationship, so as to maintain the stability of the removal function when processing the optical element.

[0012] Furthermore, the magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a supply system, a real-time adjustment device and a magnetorheological mounting frame; wherein, the magnetorheological mounting frame is arranged on the free end of the robot, the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, and the real-time adjustment device is connected to the polishing wheel, so that the real-time adjustment device adjusts the position of the polishing wheel, thereby changing the polishing gap of the polishing wheel; the polishing motor is arranged on the magnetorheological mounting frame and is connected to the polishing wheel through a transmission belt, so that the polishing motor controls the rotation of the polishing wheel, thereby causing the polishing wheel to process the optical element; the nozzle is arranged on the magnetorheological mounting frame. The invention relates to a magnetorheological fluid mounting frame, wherein the nozzle direction of the nozzle is consistent with the rotation direction of the polishing wheel; the supply system is connected to the nozzle through a pipeline, and the supply system transports the magnetorheological fluid to the nozzle, so that the polishing wheel processes the optical element with the magnetorheological fluid as the medium; the electromagnet is connected to the real-time adjustment device, and the electromagnet is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the electromagnet and changes the stiffness of the magnetorheological fluid; at the same time, the real-time adjustment device adjusts the magnetic field strength and the distance between the electromagnet and the polishing wheel; the sensor module is set on the magnetorheological mounting frame, and the laser tracker measures the spatial coordinates of the sensor module through the target ball.

[0013] Furthermore, the sensor module includes an acceleration sensor; the laser tracker, the sensor module, the robot and the real-time adjustment device are respectively connected to the control unit to form respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

[0014] Furthermore, the real-time adjustment device includes a displacement output motor, a screw, a support and fixing frame, and a current intensity controller; wherein, the support and fixing frame is arranged on a magnetorheological mounting frame, the displacement output motor is arranged on the support and fixing frame, and the displacement output motor is connected to the screw arranged on the support and fixing frame; the electromagnet or polishing wheel is simultaneously connected to the nut on the screw, so that the screw drives the electromagnet or polishing wheel to move; the current intensity controller is connected to the electromagnet through a wire, and power is supplied to the electromagnet to generate a magnetic field; the current intensity controller is communicatively connected to the control unit, and the control unit sends a control signal to the current intensity controller, and the current intensity controller adjusts the current transmitted to the electromagnet according to the control signal, thereby changing the magnetic field strength of the electromagnet.

[0015] A magnetorheological polishing method based on magnetic field strength, based on a magnetorheological polishing device based on sensor-adjusted electromagnets provided by the present invention, comprises the following steps:

[0016] A1: Use a laser tracker to obtain the first coordinate of the sensor module and the second coordinate of the polishing wheel working point; use the coordinate relationship module to calculate the coordinate transformation relationship based on the two coordinates;

[0017] A2: Using the coordinate relationship module, the first theoretical coordinates of the working point of the polishing wheel at different polishing trajectory points are converted into the second theoretical coordinates of the sensor module through the coordinate transformation relationship, and the theoretical straight-line distance is obtained based on the current second theoretical coordinate and the previous second theoretical coordinate;

[0018] A3: Use the coordinate relationship module to record the measurement results of the sensor module to obtain the actual straight-line distance. The coordinate relationship module is used to calculate the distance error between the actual straight-line distance and the theoretical straight-line distance.

[0019] A4: Controlling the magnetorheological processing module to perform fixed-point processing on the test optical element, and obtaining a first conversion relationship through the conversion relationship module;

[0020] A5: Set the distance error threshold, the maximum control value, and the maximum magnetic field strength; determine the processing conditions based on the distance error, the distance difference threshold, and the maximum control value; based on the processing conditions, process the optical element to be processed in combination with the first conversion relationship and the maximum magnetic field strength, and control the magnetic field strength of the electromagnet in real time through the real-time control module during the processing.

[0021] Furthermore, in step A1, the laser tracker obtains the coordinates of no less than four positions on the sensor module through the target sphere, and obtains the first coordinate (x1, y1, z1) by calculation;

[0022] The laser tracker obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel through the target ball, and then calculates the coordinates of the center point of the polishing wheel (x2, y2, z2). The straight line passing through the coordinates of the center point is:

[0023] ;

[0024] Among them, (a, b, c) represents the normal vector of the line at the center point coordinates;

[0025] By solving the following set of equations, we can find the spatial coordinates corresponding to the minimum value of the Z-axis coordinate and use them as the second coordinates (x, y, z):

[0026] ;

[0027] Where R represents the radius of the polishing wheel;

[0028] The coordinate transformation relationship is obtained by combining the second coordinate with the first coordinate:

[0029] ;

[0030] Where T represents the coordinate transformation relationship.

[0031] Furthermore, in step A2, the theoretical straight-line distance is obtained by the following formula:

[0032] ;

[0033] in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

[0034] Furthermore, in step A3, the actual straight-line distance is obtained by the following formula:

[0035] ;

[0036] Among them, d ri Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; a i-1 represents the acceleration measured by the sensor module at the previous polishing track point, v i-1 represents the speed measured by the sensor module at the previous polishing track point, and t represents the measurement time of the sensor module; the distance error is obtained by the following formula :

[0037] .

[0038] Furthermore, step A4 specifically includes the following steps:

[0039] A41: Under different polishing gaps, the magnetic field strength is changed separately, and processing is performed at different positions of the test optical element. The removal function volume removal rate of each polishing track point is calculated, and the third conversion relationship between the removal function volume removal rate and the magnetic field strength is obtained:

[0040] B=F bm (MRR);

[0041] Where B represents the magnetic field strength, MRR represents the removal function volume removal rate, and F bm Indicates the third conversion relationship;

[0042] A42: Control the polishing wheel to perform fixed-point processing at different positions of the test optical element with different polishing gaps for a period of time, and calculate the removal function volume removal rate of each polishing track point to obtain the fourth conversion relationship between the removal function volume removal rate and the polishing gap:

[0043] MRR=F mg(gap);

[0044] Among them, gap represents the polishing gap, F mg Indicates the fourth conversion relationship;

[0045] A43: According to the third conversion relationship and the fourth conversion relationship, the first conversion relationship is obtained:

[0046] B=F bg (gap)=F bm (F mg (gap));

[0047] Among them, F bg Indicates the first conversion relationship.

[0048] Further, in step A5, when the polishing wheel is located at the i-th polishing track point, the distance error Distance difference threshold Compare:

[0049] like , then the current magnetic field strength B i to regulate;

[0050] like , then for the current magnetic field strength B i To regulate:

[0051] If the current magnetic field strength B i Less than the maximum magnetic field strength |B max |, the real-time control module is based on the first conversion relationship F bg The current magnetic field strength B i Make adjustments;

[0052] ;

[0053] If the current magnetic field strength B i Greater than or equal to the maximum magnetic field strength |B max |, the current magnetic field strength B i Adjust to ±|B max |.

[0054] A magnetorheological polishing method based on electromagnet position adjustment, based on the magnetorheological polishing device based on sensor adjustment of electromagnet provided by the present invention, comprises the following steps:

[0055] B1: Use a laser tracker to obtain the first coordinate of the sensor module and the second coordinate of the polishing wheel working point; use the coordinate relationship module to calculate the coordinate transformation relationship based on the two coordinates;

[0056] B2: Using the coordinate relationship module, the first theoretical coordinates of the working point of the polishing wheel at different polishing trajectory points are converted into the second theoretical coordinates of the sensor module through the coordinate conversion relationship, and the theoretical straight-line distance is obtained based on the current second theoretical coordinate and the previous second theoretical coordinate;

[0057] B3: Use the coordinate relationship module to record the measurement results of the sensor module to obtain the actual straight-line distance; the actual straight-line distance and the theoretical straight-line distance are calculated using the coordinate relationship module to obtain the distance error;

[0058] B4: Control the magnetorheological processing module to perform fixed-point processing on the test optical element, and obtain a second conversion relationship through the conversion relationship module;

[0059] B5: Set the distance error threshold, the maximum control value, and the maximum electromagnet position; determine the processing conditions based on the distance error, the distance difference threshold, and the maximum control value; based on the processing conditions, the optical element to be processed is processed in combination with the second conversion relationship and the maximum electromagnet position, and the magnetorheological processing module is controlled in real time through the real-time control module during the processing.

[0060] Furthermore, in step B1, the laser tracker obtains the coordinates of no less than four positions on the sensor module through the target sphere, and obtains the first coordinate (x1, y1, z1) by calculation;

[0061] The laser tracker obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel through the target ball, and then calculates the coordinates of the center point of the polishing wheel (x2, y2, z2). The straight line passing through the center point coordinates is:

[0062] ;

[0063] Among them, (a, b, c) represents the normal vector of the line at the center point coordinates;

[0064] By solving the following set of equations, we can find the spatial coordinates corresponding to the minimum value of the Z-axis coordinate and use them as the second coordinates (x, y, z):

[0065] ;

[0066] Where R represents the radius of the polishing wheel;

[0067] Obtain the coordinate transformation relationship through the second coordinate and the first coordinate

[0068] ;

[0069] Where T represents the coordinate transformation relationship.

[0070] Furthermore, in step B2, the theoretical straight-line distance is obtained by the following formula:

[0071] ;

[0072] Among them, d i Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

[0073] Furthermore, in step B3, the actual straight-line distance is obtained by the following formula:

[0074] ;

[0075] Among them, d ri Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; a i-1 represents the acceleration measured by the sensor module at the previous polishing track point, v i-1 Represents the speed measured by the sensor module at the previous polishing track point, Represents the measurement time of the sensor module; the distance error is obtained by the following formula :

[0076] .

[0077] Furthermore, step B4 includes the following steps:

[0078] B41: Under different polishing gaps, the electromagnet position is changed individually. The test optical element is processed at different polishing gaps for a period of time. The removal function volume removal rate of each polishing track point is calculated, and the fifth conversion relationship between the removal function volume removal rate and the electromagnet position is obtained:

[0079] LT=F tm (MRR);

[0080] Where LT represents the position of the electromagnet, MRR represents the removal function volume removal rate, F tm Indicates the fifth conversion relationship;

[0081] B42: Keeping the distance between the polishing wheel and the electromagnet constant, control the robot to drive the polishing wheel to process different positions of the test optical element with different polishing gaps, and calculate the removal function volume removal rate of each polishing trajectory point to obtain the sixth conversion relationship between the removal function volume removal rate and the polishing gap:

[0082] MRR=F mg (gap);

[0083] Among them, gap represents the polishing gap, F mg Indicates the sixth conversion relationship;

[0084] B43: Obtain the second conversion relationship based on the fifth conversion relationship and the sixth conversion relationship, namely:

[0085] LT=F tg (gap)=F tm (F mg (gap));

[0086] Among them, F tg Indicates the second conversion relationship.

[0087] Further, in step B5, when the polishing wheel is located at the i-th polishing track point, the distance error Distance difference threshold Compare:

[0088] like , then the current electromagnet position LT is not correct i Make adjustments:

[0089] like , then the current electromagnet position LT i Make adjustments:

[0090] If the current electromagnet position LT i Less than the maximum solenoid position |LT max |When the current electromagnet position LT i Control is performed according to the following formula:

[0091] ;

[0092] If the current electromagnet position LT i Greater than the maximum solenoid position |LT max |When the current electromagnet position LT i Adjust to ±|LT max |.

[0093] A magnetorheological polishing method based on magnetic field strength and polishing wheel movement is based on a magnetorheological polishing device based on sensor-adjusted electromagnets provided by the present invention, comprising the following steps:

[0094] C1: Use a laser tracker to obtain the first coordinate of the sensor module and the second coordinate of the polishing wheel working point; use the coordinate relationship module to calculate the coordinate transformation relationship based on the two coordinates;

[0095] C2: Using the coordinate relationship module, through the coordinate transformation relationship, the first theoretical coordinates of the working point of the polishing wheel at different polishing trajectory points are converted into the second theoretical coordinates of the sensor module, and the theoretical straight-line distance is obtained based on the current second theoretical coordinate and the previous second theoretical coordinate;

[0096] C3: Use the coordinate relationship module to record the measurement results of the sensor module to obtain the actual straight-line distance; the actual straight-line distance and the theoretical straight-line distance are calculated through the coordinate relationship module to obtain the distance error;

[0097] C4: Set the distance error threshold, control maximum value, maximum electromagnet position, maximum magnetic field strength and maximum polishing gap; determine the processing conditions based on the distance error, distance difference threshold and control maximum value; based on the processing conditions, the optical element to be processed is processed in combination with the maximum magnetic field strength and maximum polishing gap, and the magnetorheological processing module is controlled in real time through the real-time control module during the processing.

[0098] Furthermore, in step C1, the laser tracker obtains the coordinates of no less than four positions on the sensor module through the target sphere, and obtains the first coordinate (x1, y1, z1) by calculation;

[0099] The laser tracker obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel through the target ball, and then calculates the coordinates of the center point of the polishing wheel (x2, y2, z2). The straight line passing through the center point coordinates is:

[0100] ;

[0101] Among them, (a, b, c) represents the normal vector of the line at the center point coordinates;

[0102] By solving the following set of equations, we can find the spatial coordinates corresponding to the minimum value of the Z-axis coordinate and use them as the second coordinates (x, y, z):

[0103] ;

[0104] Where R represents the radius of the polishing wheel;

[0105] The coordinate transformation relationship is obtained by combining the second coordinate with the first coordinate:

[0106] ;

[0107] Where T represents the coordinate transformation relationship.

[0108] Furthermore, in step C2, the theoretical straight-line distance is obtained by the following formula:

[0109] ;

[0110] in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

[0111] Furthermore, in step C3, the actual straight-line distance is obtained by the following formula:

[0112] ;

[0113] Among them, d ri Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; a i-1 represents the acceleration measured by the sensor module at the previous polishing track point, v i-1 represents the speed measured by the sensor module at the previous polishing track point, and t represents the measurement time of the sensor module; the distance error is obtained by the following formula :

[0114] .

[0115] Furthermore, in step C4, when the polishing wheel is located at the i-th polishing track point, the distance error Distance difference threshold Compare:

[0116] like , then the current magnetic field strength and the current polishing gap are not regulated;

[0117] like , then the current magnetic field strength and the current polishing gap are regulated:

[0118] If the current magnetic field strength B i Less than the maximum magnetic field strength |B max |, and the current polishing gap gap i Smaller than the maximum polishing gap max |, current magnetic field strength B i and the current polishing gap i They are regulated according to the following formulas:

[0119] ;

[0120] Wherein, gap0 is the initial polishing gap of the polishing wheel, r is the distance between the lowest point of the polishing wheel and the electromagnet, M is the magnetic moment, and k is the proportional coefficient;

[0121] If the current magnetic field strength B i Greater than or equal to the maximum magnetic field strength |B max|, and the current polishing gap gap i Greater than or equal to the maximum polishing gap|gap max |, current magnetic field strength B i Adjust to ±|B max |, current polishing gap i Adjust to ±|gap max |.

[0122] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0123] In the magnetorheological polishing equipment and method based on sensor-adjusted electromagnets created by the present invention, the six-dimensional posture information of the robot during the processing is measured in real time by cooperating with a laser tracker and a sensor module, and the position or magnetic field strength of the electromagnet in the magnetorheological processing module is adjusted in real time, thereby realizing real-time constant control of the removal function change under multi-factor coupling during the processing of optical elements; at the same time, the acquisition of posture information does not need to rely on the actual processing process, and the posture error information of the processing equipment can be obtained during the processing trial run (in which magnetorheological fluid is not introduced and no processing effect is produced), and there is no need to place the measuring equipment at the lowest point of the polishing wheel, which will not affect the actual processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0125] Figure 1 A schematic structural diagram of a magnetorheological polishing device based on sensor-adjusted electromagnets according to an embodiment of the present invention from one perspective;

[0126] Figure 2 A schematic structural diagram of a magnetorheological polishing device based on sensor-adjusted electromagnets according to an embodiment of the present invention from another perspective;

[0127] Figure 3 This is a schematic structural diagram of the magnetorheological processing module according to an embodiment of the present invention. Figure 3 (a) is a structural diagram of the magnetorheological processing module from one perspective. Figure 3 (b) is a structural diagram of the magnetorheological processing module from another perspective;

[0128] Figure 4 This is a structural diagram of the real-time adjustment device described in an embodiment of the present invention.

[0129] Description of reference numerals:

[0130] 1. Robot; 2. Sensor module; 3. Laser tracker; 4. Control unit; 5. Laboratory bench; 6. Optical element to be processed; 7. Test optical element; 8. Target ball; 9. Polishing wheel; 10. Electromagnet; 11. Transmission belt; 12. Polishing motor; 13. Nozzle; 14. Real-time adjustment device; 15. Magnetorheological mounting bracket; 16. Displacement output motor; 17. Guide rail; 18. Slider; 19. Lead screw; 20. Nut; 21. Support bracket; 22. Connecting plate; 23. Current intensity controller. DETAILED DESCRIPTION

[0131] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0132] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0133] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0134] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0135] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0136] like Figures 1 to 4 As shown, the magnetorheological polishing device based on sensor-adjusted electromagnets according to an embodiment of the present invention includes a robot 1, a magnetorheological processing module, a sensor module 2, a laser tracker 3, and a control unit 4. The magnetorheological processing module is arranged at the free end of the robot 1, and the robot 1 drives the magnetorheological processing module to process the optical element 6 to be processed and the test optical element 7 placed on the experimental table 5. The sensor module 2 is arranged on the magnetorheological processing module, and the laser tracker 3 cooperates with the target ball 8 arranged on the magnetorheological processing module to measure the spatial coordinates of the working points of the sensor module 2 and the polishing wheel 9 in the magnetorheological processing module. In this embodiment of the present invention, the laser tracker 3 is set on one side of the experimental table 5, and the position of the target ball 8 is adjusted according to the needs of the measurement object. For example, when the spatial coordinates of the sensor module 2 need to be measured, the target ball 8 is installed at the corresponding position of the sensor module 2, and when the polishing wheel 9 needs to be measured, the target ball 8 is installed at the corresponding position of the polishing wheel 9.

[0137] The control unit 4 includes a coordinate relationship module, a conversion relationship module and a real-time control module. Among them, the coordinate relationship module integrates and calculates the spatial coordinates collected by the laser tracker 3 and the position information collected by the sensor module 2, and outputs the integrated position information. The conversion relationship module fits the magnetic field strength of the electromagnet 10 in the magnetorheological processing module with the polishing gap of the polishing wheel 9 to obtain a first conversion relationship, and fits the electromagnet position of the electromagnet 10 with the polishing gap of the polishing wheel 9 to obtain a second conversion relationship. In the embodiment of the present invention, the electromagnet position is defined as the distance between the electromagnet 10 and the optical element to be processed 6 or the test optical element 7. The real-time control module adjusts the magnetic field strength of the electromagnet 10 according to the integrated position information and the first conversion relationship, and / or adjusts the position of the electromagnet 10 according to the integrated position information and the second conversion relationship, so as to maintain the stability of the removal function when processing the optical element 6 to be processed.

[0138] Figure 3 (a) and (b) in the figure respectively show the structural schematic diagrams of the magnetorheological processing module from two different perspectives. Figure 3As shown, the magnetorheological processing module also includes a transmission belt 11, a polishing motor 12, a nozzle 13, a supply system, a real-time adjustment device 14, and a magnetorheological mounting frame 15. The magnetorheological mounting frame 15 is mounted on the free end of the robot 1, and the polishing wheel 9 and the real-time adjustment device 14 are mounted on the magnetorheological mounting frame 15. The real-time adjustment device 14 is connected to the polishing wheel 9 via a connecting plate 22. Specifically, the head end of the connecting plate 22 is mounted on the real-time adjustment device 14, and the polishing wheel 9 is mounted on the end of the connecting plate 22. The real-time adjustment device 14 adjusts the position of the polishing wheel 9, thereby changing the polishing gap of the polishing wheel 9. The polishing motor 12 is mounted on the magnetorheological mounting frame 15. The output end of the polishing motor 12 passes through the end of the connecting plate 22, so that the output end of the polishing motor 12 is connected to the bearing of the polishing wheel 9 through the transmission belt 11, so that the polishing motor 12 controls the rotation of the polishing wheel 9, thereby causing the polishing wheel 9 to process the optical element 6 to be processed or the test optical element 7. The manner in which the polishing motor 12 drives the polishing wheel 9 to rotate in the embodiment of the present invention can be referred to the invention patent application with Chinese patent publication number CN118322074A, publication date July 12, 2024, and patent name "Self-rotating polishing module processing system". The nozzle 13 is arranged on the magnetorheological mounting frame 15 along the rotation direction of the polishing wheel 9. The supply system delivers magnetorheological fluid to the nozzle 13, and the nozzle 13 sprays magnetorheological fluid toward the working point of the polishing wheel 9, thereby causing the polishing wheel 9 to process the optical element 6 to be processed or the test optical element 7 using the magnetorheological fluid as a medium. In the embodiment of the present invention, the working point of the polishing wheel 9 is specified to be along the normal direction of the surface of the optical element 6 to be processed or the test optical element 7, and the closest point between the polishing wheel 9 and the surface of the optical element is the working point of the polishing wheel 9. The electromagnet 10 is connected to the real-time adjustment device 14 via a connecting plate 22, and is positioned close to the working point of the polishing wheel 9. Specifically, one end of the connecting plate 22 is mounted on the real-time adjustment device 14, and the electromagnet 10 is mounted on the other end of the connecting plate 22. This allows the magnetorheological fluid to be affected by the magnetic field strength of the electromagnet 10, changing its stiffness, and allowing the polishing wheel 9 to process the optical element 6 to be processed or the test optical element 7 using the magnetorheological fluid with a certain stiffness as a medium. Simultaneously, the real-time adjustment device 14 adjusts the magnetic field strength and the distance between the electromagnet 10 and the polishing wheel 9. The sensor module 2 is placed on the magnetorheological mounting frame 15, and the laser tracker 3 measures the spatial coordinates of the sensor module 2 via the target sphere 8.

[0139] In the embodiment of the present invention, the structure of the real-time adjustment device 14 for controlling the electromagnet 10 and the polishing wheel 9 is as follows: Figure 2 and Figure 4As shown, the apparatus comprises a displacement output motor 16, a lead screw 19, a support bracket 21, and a current intensity controller 23. The lead screw 19 and a nut 20 with a ball bearing thereon together form a ball screw. The support bracket 21 is mounted on the magnetorheological mounting frame 15. The displacement output motor 16 is mounted on top of the support bracket 21. The displacement output motor 16 is connected to the lead screw 19 mounted on the support bracket 21. The electromagnet 10 and the polishing wheel 9 are simultaneously connected to the nut 20. In an embodiment of the present invention, the electromagnet 10 and the polishing wheel 9 are connected to the nut 20 via a connecting plate 22, so that the lead screw 19 drives the electromagnet 10 and the polishing wheel 9 to move along the lead screw 19. In an embodiment of the present invention, to ensure stable movement of the electromagnet 10 and the polishing wheel 9, two guide rails 17 parallel to the lead screw 19 are further provided on the support bracket 21. The two guide rails 17 are located on either side of the lead screw 19. At this time, the connecting plate 22 is simultaneously fixedly connected to the sliders 18 on the two guide rails 17 and the nut 20. During the machining process, control unit 4 sends a control signal to displacement output motor 16. When displacement output motor 16 drives lead screw 19 to rotate, lead screw 19 cooperates with two guide rails 17 to pull connecting plate 22, thereby driving electromagnet 10 or polishing wheel 9 to move along lead screw 19. Current intensity controller 23 is connected to electromagnet 10 via a wire and is used to energize electromagnet 10 to generate a magnetic field. Current intensity controller 23 is also in communication with control unit 4. Control unit 4 sends a control signal to current intensity controller 23. Current intensity controller 23 adjusts the current transmitted to electromagnet 10 based on the control signal, thereby changing the magnetic field strength of electromagnet 10. In this embodiment of the present invention, current intensity controller 23 preferably adopts Siemens Smart200 series DA conversion module.

[0140] In an embodiment of the present invention, the sensor module 2 includes an acceleration sensor. The robot 1, sensor module 2, laser tracker 3, and real-time adjustment device 14 are each connected to the control unit 4 to form respective communication lines, enabling the control unit 4 to receive and send signals via the corresponding communication lines. Specifically, the control unit 4 receives signals from the sensor module 2 and laser tracker 3 via the communication lines. The control unit 4 sends a control signal to change the position of the electromagnet 10 or polishing wheel 9 to the displacement output motor 16 in the real-time adjustment device 14 via the communication lines. The control unit 4 also sends a control signal to change the magnetic field strength of the electromagnet 10 to the current intensity controller 23 in the real-time adjustment device 14 via the communication lines. Because a strong magnetic field is generated around the polishing wheel 9 during polishing, the communication lines avoid strong magnetic fields.

[0141] Based on the magnetorheological polishing equipment based on sensor-adjusted electromagnets described in the embodiments of the present invention, the embodiments of the present invention also provide a magnetorheological polishing method based on sensor-adjusted electromagnets, including a magnetorheological polishing method based on magnetic field strength, a magnetorheological polishing method based on electromagnet position adjustment, and a magnetorheological polishing method based on magnetic field strength and polishing wheel movement.

[0142] Specific embodiment 1: The magnetorheological polishing method based on magnetic field strength provided in this specific embodiment is based on the magnetorheological polishing device based on sensor-adjusted electromagnets according to the invention, combined with Figures 1 to 4 , including the following steps:

[0143] A1: Use the laser tracker 3 to obtain the first coordinate of the sensor module 2 and the second coordinate of the working point of the polishing wheel 9. Use the coordinate relationship module to calculate the coordinate transformation relationship based on the two coordinates.

[0144] In step A1, this specific embodiment uses a cylindrical or rectangular acceleration sensor as the sensor module 2, and obtains the coordinates of no less than four positions on the sensor module 2 through the laser tracker 3 and the target ball 8, and obtains the first coordinate .

[0145] Specifically, for the cylindrical acceleration sensor, the target ball 8 is placed at least three different positions on the cylindrical bottom of the cylindrical acceleration sensor, and the spatial coordinates of the target ball 8 are measured using the laser tracker 3. The circle fitting function of the laser tracker 3 (this function is the basic function of the laser tracker 3) is used to obtain the XY coordinates of the cylindrical acceleration sensor. , based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the bottom surface of the cylindrical accelerometer , k represents the number of measurement points. The target ball 8 is placed at least three different positions on the top of the cylindrical acceleration sensor and its spatial coordinates are measured using the laser tracker 3. The Z-axis coordinates of the target ball 8 at different positions are Calculate the Z-axis coordinate of the top surface of the cylindrical accelerometer. , where j represents the number of measurement points, and the first coordinate of the cylindrical accelerometer is , r is the radius of the target sphere 8. In this specific embodiment, for the cylindrical acceleration sensor, 10 different positions are selected at the bottom and top thereof.

[0146] For the rectangular acceleration sensor, the target balls 8 are placed at the bottom of the four sides of the rectangular acceleration sensor and the spatial coordinates are measured using the laser tracker 3. The coordinates of the eight points of the target ball are measured at the bottom of each side. The coordinates of the bottom of the four sides of the rectangular acceleration sensor are obtained as follows: 、 、 、 , solve the XY axis coordinates of the rectangular acceleration sensor as , based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the bottom surface of the rectangular accelerometer and get The target ball 8 is placed at least three different positions on the top of the rectangular acceleration sensor and its spatial coordinates are measured using a laser tracker 3, based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the top surface of the rectangular accelerometer. , the first coordinate of the rectangular acceleration sensor is In this specific embodiment, for the rectangular parallelepiped acceleration sensor, 10 different positions are selected on the top thereof.

[0147] The laser tracker 3 obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel 9 through the target ball 8 (in this specific embodiment, the coordinates of 10 different positions are obtained). The coordinate calculation function of the laser tracker 3 itself can obtain the coordinates of the center point of the polishing wheel 9. , and the straight line passing through the center point coordinates is obtained through the teaching pendant of robot 1:

[0148] ;

[0149] in, The normal vector of the line representing the coordinates of the center point;

[0150] By solving the following equations, the spatial coordinate corresponding to the minimum value of the Z-axis coordinate is used as the second coordinate :

[0151] ;

[0152] in, Indicates the radius of the polishing wheel 9.

[0153] The coordinate transformation relationship is obtained by combining the second coordinate with the first coordinate:

[0154] ;

[0155] in, Represents the coordinate transformation relationship.

[0156] A2: Using the coordinate relationship module, the first theoretical coordinates of the working point of the polishing wheel 9 at different polishing trajectory points are converted into the second theoretical coordinates of the sensor module 2 through the coordinate transformation relationship. The theoretical straight-line distance is calculated based on the current second theoretical coordinate and the previous second theoretical coordinate. In this specific embodiment, the theoretical straight-line distance is the distance in the Z-axis direction.

[0157] In step A2, the theoretical straight-line distance is obtained by the following formula:

[0158] ;

[0159] in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

[0160] A3: Use the coordinate relationship module to record the measurement results of sensor module 2 to obtain the actual straight-line distance. The coordinate relationship module calculates the distance error between the actual straight-line distance and the theoretical straight-line distance. In this specific embodiment, the actual straight-line distance is the distance in the Z-axis direction.

[0161] In step A3, the actual straight-line distance is obtained by the following formula:

[0162] ;

[0163] in, Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; represents the acceleration measured by sensor module 2 at the previous polishing track point, represents the speed measured by sensor module 2 at the previous polishing track point, represents the measurement time of sensor module 2. The distance error is obtained by the following formula: :

[0164] .

[0165] A4: Control the magnetorheological processing module to perform fixed-point processing on the test optical element 7, and obtain a first conversion relationship through the conversion relationship module. Step A4 specifically includes the following steps:

[0166] A41: Under different polishing gaps, the magnetic field strength is changed individually, and processing is performed at different positions of the test optical element 7. The removal function volume removal rate of each polishing track point is calculated, and the third conversion relationship between the removal function volume removal rate and the magnetic field strength is obtained:

[0167] ;

[0168] in, represents the magnetic field strength, represents the removal function volume removal rate, It represents the third conversion relationship. In this specific embodiment, the fixed-point processing is performed at different positions of the test optical element 7 for a period of time with different magnetic field intensities.

[0169] A42: Control the polishing wheel 9 to perform fixed-point processing at different positions of the test optical element 7 for a period of time with different polishing gaps, and calculate the volume removal rate of the removal function at each polishing trajectory point to obtain a fourth conversion relationship between the volume removal rate of the removal function and the polishing gap:

[0170] ;

[0171] in, Indicates the polishing gap, It represents the fourth conversion relationship. In this specific embodiment, it specifically controls the polishing wheel 9 to perform fixed-point processing at different positions of the test optical element 7 for a period of time with different polishing gaps.

[0172] A43: According to the third conversion relationship and the fourth conversion relationship, the first conversion relationship is obtained:

[0173] ;

[0174] in, Indicates the first conversion relationship.

[0175] A5: Set a distance error threshold, a maximum control value, and a maximum magnetic field strength; determine processing conditions based on the distance error, the distance difference threshold, and the maximum control value; based on the processing conditions, process the optical element 6 to be processed in combination with the first conversion relationship and the maximum magnetic field strength, and during the processing, use the real-time control module to control the magnetic field strength of the electromagnet 10 in real time. The distance error threshold, the maximum control value, and the maximum magnetic field strength are set adaptively based on actual conditions and are not limited in this embodiment.

[0176] When the polishing wheel 9 is at When there are 3 polishing track points, the distance error Distance difference threshold Compare:

[0177] like , then the current magnetic field strength is not to regulate;

[0178] like , then the current magnetic field strength To regulate:

[0179] If the current magnetic field strength Less than the maximum magnetic field strength When The real-time control module is based on the first conversion relationship Current magnetic field strength Make adjustments;

[0180] ;

[0181] If the current magnetic field strength Greater than or equal to the maximum magnetic field strength When , current magnetic field strength Adjust to .

[0182] In this specific embodiment, the amount of discrete data corresponding to different polishing gaps obtained experimentally is limited. The polishing gap actually measured during processing may not be equal to the polishing gap data value obtained experimentally. The solution is to use the closest data, that is, the rounding principle. For example: the removal function volume removal rate MRR and magnetic field strength corresponding to polishing gaps of 1mm and 2mm were obtained experimentally. The fourth conversion relationship between them is used to obtain the corresponding first conversion relationship, but the polishing gap during the processing is 1.6 mm. At this time, the fourth conversion relationship is used to calculate the 2 mm removal function volume removal rate MRR.

[0183] Specific embodiment 2: The magnetorheological polishing method based on electromagnet position adjustment provided in this specific embodiment is based on the magnetorheological polishing device based on sensor adjustment of electromagnet according to the embodiment of the invention, combined with Figures 1 to 4 , including the following steps:

[0184] B1: Use the laser tracker 3 to obtain the first coordinate of the sensor module 2 and the second coordinate of the working point of the polishing wheel 9; and use the coordinate relationship module to calculate the coordinate conversion relationship through the two coordinates.

[0185] In step B1, in this specific embodiment, a cylindrical or rectangular acceleration sensor is used as the sensor module 2, and the coordinates of no less than four positions on the sensor module 2 are obtained by using the laser tracker 3 in conjunction with the target ball 8. The first coordinate is obtained by calculation. .

[0186] Specifically, for the cylindrical acceleration sensor, the target ball 8 is placed at least three different positions on the cylindrical bottom of the cylindrical acceleration sensor and its spatial coordinates are measured using the laser tracker 3. The circle fitting function of the laser tracker 3 (this function is the basic function of the laser tracker 3) is used to obtain the XY coordinates of the cylindrical acceleration sensor. , based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the bottom surface of the cylindrical accelerometer. , k represents the number of measurement points. The target ball 8 is placed at least three different positions on the top of the cylindrical acceleration sensor and its spatial coordinates are measured using the laser tracker 3. The Z-axis coordinates of the target ball 8 at different positions are Calculate the Z-axis coordinate of the top surface of the cylindrical accelerometer. , where j represents the number of measurement points, and the first coordinate of the cylindrical accelerometer is , r is the radius of the target sphere 8. In this specific embodiment, for the cylindrical acceleration sensor, 10 different positions are selected at the bottom and top thereof.

[0187] For the rectangular acceleration sensor, the target balls 8 are placed at the bottom of the four sides of the rectangular acceleration sensor and the spatial coordinates are measured using the laser tracker 3. The coordinates of the eight points of the target ball are measured at the bottom of each side. The coordinates of the bottom of the four sides of the rectangular acceleration sensor are obtained as follows: 、 、 、 , solve the XY axis coordinates of the rectangular acceleration sensor as , based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the bottom surface of the rectangular accelerometer and get The target ball 8 is placed at least three different positions on the top of the rectangular acceleration sensor and its spatial coordinates are measured using a laser tracker 3, based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the top surface of the rectangular accelerometer. , the first coordinate of the rectangular acceleration sensor is In this specific embodiment, for the rectangular parallelepiped acceleration sensor, 10 different positions are selected on the top thereof.

[0188] The laser tracker 3 obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel 9 through the target ball 8 (in this specific embodiment, the coordinates of 10 different positions are obtained). The coordinate calculation function of the laser tracker 3 itself can obtain the coordinates of the center point of the polishing wheel 9. , and the straight line passing through the center point coordinates is obtained through the teaching pendant of robot 1:

[0189] ;

[0190] in, The normal vector of the line representing the coordinates of the center point;

[0191] By solving the following equations, the spatial coordinate corresponding to the minimum value of the Z-axis coordinate is used as the second coordinate :

[0192] ;

[0193] in, Indicates the radius of the polishing wheel 9.

[0194] The coordinate transformation relationship is obtained by combining the second coordinate with the first coordinate:

[0195] ;

[0196] in, Represents the coordinate transformation relationship.

[0197] B2: Using the coordinate relationship module, the first theoretical coordinates of the working point of the polishing wheel 9 at different polishing trajectory points are converted into the second theoretical coordinates of the sensor module 2 through the coordinate conversion relationship. The theoretical straight-line distance is obtained based on the current second theoretical coordinate and the previous second theoretical coordinate. In this specific embodiment, the theoretical straight-line distance is the distance in the Z-axis direction.

[0198] In step B2, the theoretical straight-line distance is obtained by the following formula:

[0199] ;

[0200] in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

[0201] B3: Use the coordinate relationship module to record the measurement results of the sensor module 2 to obtain the actual straight-line distance; the coordinate relationship module calculates the distance error between the actual straight-line distance and the theoretical straight-line distance. In this specific embodiment, the actual straight-line distance is the distance in the Z-axis direction.

[0202] In step B3, the actual straight-line distance is obtained by the following formula:

[0203] ;

[0204] in, Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; represents the acceleration measured by sensor module 2 at the previous polishing track point, represents the speed measured by sensor module 2 at the previous polishing track point, Represents the measurement time; the distance error is obtained by the following formula :

[0205] .

[0206] B4: Control the magnetorheological processing module to perform fixed-point processing on the test optical element 7, and obtain a second conversion relationship through the conversion relationship module, specifically:

[0207] B41: Under different polishing gaps, the electromagnet position is changed individually, and the test optical element 7 is processed with different polishing gaps. The removal function volume removal rate of each polishing track point is calculated to obtain the fifth conversion relationship between the removal function volume removal rate and the electromagnet position:

[0208] ;

[0209] in, Indicates the position of the electromagnet, represents the removal function volume removal rate, Indicates the fifth conversion relationship; in this specific embodiment, the test optical element 7 is specifically processed at a fixed point for a period of time with different polishing gaps;

[0210] B42: Keeping the distance between the polishing wheel 9 and the electromagnet 10 unchanged, control the robot 1 to drive the polishing wheel 9 to process different positions of the test optical element 7 with different polishing gaps, and calculate the removal function volume removal rate of each polishing trajectory point to obtain the sixth conversion relationship between the removal function volume removal rate and the polishing gap:

[0211] ;

[0212] in, Indicates the polishing gap, Indicates the sixth conversion relationship; in this specific embodiment, specifically with different polishing gaps Performing fixed-point processing for a period of time at different positions of the test optical element 7;

[0213] B44: Obtain the second conversion relationship based on the fifth conversion relationship and the sixth conversion relationship, namely:

[0214] ;

[0215] in, Indicates the second conversion relationship.

[0216] B5: Setting a distance error threshold, a maximum control value, and a maximum electromagnet position; determining processing conditions based on the distance error, the distance difference threshold, and the maximum control value; processing the optical element 6 to be processed based on the processing conditions, in combination with the second conversion relationship and the maximum electromagnet position, and performing real-time control of the magnetorheological processing module during processing using the real-time control module. The distance error threshold, the maximum control value, and the maximum electromagnet position are set based on actual conditions and are not limited in this embodiment.

[0217] Further, in step B5, when the polishing wheel 9 is located at When there are 3 polishing track points, the distance error Distance difference threshold Compare:

[0218] like , then the current electromagnet position is not correct Make adjustments:

[0219] like , then the current electromagnet position Make adjustments:

[0220] If the current electromagnet position Less than the maximum solenoid position When , current electromagnet position Control is performed according to the following formula:

[0221] ;

[0222] If the current electromagnet position Greater than or equal to the maximum electromagnet position When , current electromagnet position Adjust to .

[0223] In this specific embodiment, the amount of discrete data corresponding to different polishing gaps obtained experimentally is limited. The polishing gap actually measured during processing may not be equal to the polishing gap data value obtained experimentally. The solution is to use the closest data, that is, the rounding principle. For example: the removal function volume removal rate MRR and electromagnet position corresponding to polishing gaps of 1mm and 2mm were obtained experimentally. The fifth conversion relationship between them is used to obtain the corresponding second conversion relationship, but the polishing gap during the processing is 1.6mm. At this time, the fifth conversion relationship is used to calculate the 2mm removal function volume removal rate MRR.

[0224] Specific embodiment 3: The magnetorheological polishing method based on magnetic field strength and polishing wheel movement provided in this specific embodiment is based on the magnetorheological polishing device based on sensor-adjusted electromagnet of the invention, combined with Figures 1 to 4 , including the following steps:

[0225] C1: Use the laser tracker 3 to obtain the first coordinate of the sensor module 2 and the second coordinate of the working point of the polishing wheel 9; use the coordinate relationship module to calculate the coordinate conversion relationship through the two coordinates.

[0226] In step C1, in this specific embodiment, a cylindrical or rectangular acceleration sensor is used as the sensor module 2, and the coordinates of no less than four positions on the sensor module 2 are obtained by using the laser tracker 3 in conjunction with the target ball 8. The first coordinate is obtained by calculation. .

[0227] For the cylindrical acceleration sensor, the target ball 8 is placed at least three different positions on the cylindrical bottom of the cylindrical acceleration sensor and its spatial coordinates are measured using the laser tracker 3. The circle fitting function of the laser tracker 3 (this function is the basic function of the laser tracker) is used to obtain the XY coordinates of the cylindrical acceleration sensor. , based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the bottom surface of the cylindrical accelerometer. , k represents the number of measurement points. The target ball 8 is placed at least three different positions on the top of the cylindrical acceleration sensor and its spatial coordinates are measured using the laser tracker 3. The Z-axis coordinates of the target ball 8 at different positions are Calculate the Z-axis coordinate of the top surface of the cylindrical accelerometer. , where j represents the number of measurement points, and the first coordinate of the cylindrical accelerometer is , r is the radius of the target sphere 8. In this specific embodiment, for the cylindrical acceleration sensor, 10 different positions are selected at the bottom and top thereof.

[0228] For the rectangular acceleration sensor, the target balls 8 are placed at the bottom of the four sides of the rectangular acceleration sensor and the spatial coordinates are measured using the laser tracker 3. The coordinates of the eight points of the target ball are measured at the bottom of each side. The coordinates of the bottom of the four sides of the rectangular acceleration sensor are obtained as follows: 、 、 、 , solve the XY axis coordinates of the rectangular acceleration sensor as , based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the bottom surface of the rectangular accelerometer and get The target ball 8 is placed at least three different positions on the top of the rectangular acceleration sensor and its spatial coordinates are measured using a laser tracker 3, based on the Z-axis coordinates of the target ball 8 at different positions Calculate the Z-axis coordinate of the top surface of the rectangular accelerometer. , the first coordinate of the rectangular acceleration sensor is In this specific embodiment, for the rectangular parallelepiped acceleration sensor, 10 different positions are selected on the top thereof.

[0229] The laser tracker 3 obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel 9 through the target ball 8 (in this specific embodiment, the coordinates of 10 different positions are obtained). The coordinate calculation function of the laser tracker 3 itself can obtain the coordinates of the center point of the polishing wheel 9. , and the straight line passing through the center point coordinates is obtained through the teaching pendant of robot 1:

[0230] ;

[0231] in, The normal vector of the line representing the coordinates of the center point;

[0232] By solving the following equations, the spatial coordinate corresponding to the minimum value of the Z-axis coordinate is used as the second coordinate :

[0233] ;

[0234] in, Indicates the radius of the polishing wheel 9.

[0235] The coordinate transformation relationship is obtained by combining the second coordinate with the first coordinate:

[0236] ;

[0237] in, Represents the coordinate transformation relationship.

[0238] C2: Using the coordinate relationship module, the first theoretical coordinates of the working point of the polishing wheel 9 at different polishing trajectory points are converted into the second theoretical coordinates of the sensor module 2 through the coordinate transformation relationship. The theoretical straight-line distance is calculated based on the current second theoretical coordinate and the previous second theoretical coordinate. In this specific embodiment, the theoretical straight-line distance is the distance in the Z-axis direction.

[0239] In step C2, the theoretical straight-line distance is obtained by the following formula:

[0240] ;

[0241] in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

[0242] C3: Use the coordinate relationship module to record the measurement results of sensor module 2 to obtain the actual straight-line distance; the coordinate relationship module calculates the distance error between the actual straight-line distance and the theoretical straight-line distance. In this specific embodiment, the actual straight-line distance is the distance in the Z-axis direction.

[0243] In step C3, the actual straight-line distance is obtained by the following formula: :

[0244] ;

[0245] in, Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; represents the acceleration measured by sensor module 2 at the previous polishing track point, represents the speed measured by sensor module 2 at the previous polishing track point, represents the measurement time of sensor module 2. The distance error is obtained by the following formula: :

[0246] .

[0247] C4: Setting a distance error threshold, maximum control value, maximum electromagnet position, maximum magnetic field strength, and maximum polishing gap; determining processing conditions based on the distance error, distance difference threshold, and maximum control value; processing the optical element 6 to be processed based on the processing conditions and the maximum magnetic field strength and maximum polishing gap, and performing real-time control of the magnetorheological processing module during processing using the real-time control module. The distance error threshold, maximum control value, maximum electromagnet position, maximum magnetic field strength, and maximum polishing gap are adaptively set based on actual conditions and are not limited in this embodiment.

[0248] In step C4, when the polishing wheel 9 is at the When there are 3 polishing track points, the distance error Distance difference threshold Compare:

[0249] like , then the current magnetic field strength and the current polishing gap are not regulated;

[0250] like , then the current magnetic field strength and the current polishing gap are regulated:

[0251] If the current magnetic field strength Less than the maximum magnetic field strength ,Right now , and the current polishing gap Smaller than the maximum polishing gap ,Right now When the current magnetic field strength and current polishing gap They are regulated according to the following formulas:

[0252] ;

[0253] ;

[0254] in, is the initial polishing gap of the polishing wheel 9, Indicates the distance between the lowest point of the polishing wheel and the electromagnet, specifically the distance between the electromagnet 10 and the lowest point of the polishing wheel 9, represents the magnetic moment, is the proportional coefficient.

[0255] If the current magnetic field strength Greater than or equal to the maximum magnetic field strength When , and the current polishing gap Greater than or equal to the maximum polishing gap ,Right now When the current magnetic field strength Adjust to , current polishing gap Adjust to .

[0256] It should be noted that, since the change of magnetic field strength is consistent with the change of polishing gap, the comparison between the current magnetic field strength and the maximum magnetic field strength will not occur in the actual processing process, which is the opposite of the comparison between the current polishing gap and the maximum polishing gap. Greater than or equal to the maximum magnetic field strength The current polishing gap Smaller than the maximum polishing gap , and the current magnetic field strength Less than the maximum magnetic field strength The current polishing gap Greater than or equal to the maximum polishing gap situation occurs.

[0257] The fitting process in the above specific embodiment includes, but is not limited to, importing discrete data into Matlab software, performing data fitting using Matlab's polyfit fitting command, and solving the respective transformation relationships. Polyfit fitting command is a basic general command in Matlab software. This method can more intuitively see the corresponding relationship between correlations and the corresponding function curve.

[0258] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0259] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A magnetorheological polishing device based on sensor-adjusted electromagnets, characterized in that: The system comprises a laser tracker, a control unit, a robot, a magnetorheological processing module, and a sensor module; the magnetorheological processing module is arranged at the free end of the robot, and the robot drives the magnetorheological processing module to process the optical element; the sensor module is arranged on the magnetorheological processing module; the laser tracker cooperates with a target ball arranged on the magnetorheological processing module to measure the spatial coordinates of the sensor module and the working point of the polishing wheel in the magnetorheological processing module; The interior of the control unit includes: A coordinate relationship module integrates and calculates the spatial coordinates collected by the laser tracker and the position information collected by the sensor module, outputs the integrated position information, and obtains the distance error; a conversion relationship module, which fits the magnetic field strength of the electromagnet in the magnetorheological processing module with the polishing gap of the polishing wheel to obtain a first conversion relationship, and fits the electromagnet position of the electromagnet with the polishing gap to obtain a second conversion relationship; A real-time control module adjusts the magnetic field strength according to the integrated position information and the first conversion relationship, and / or adjusts the position of the electromagnet according to the integrated position information and the second conversion relationship, so as to maintain the stability of the removal function when processing the optical element.

2. The magnetorheological polishing device based on sensor-adjusted electromagnet according to claim 1, characterized in that: The magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a supply system, a real-time adjustment device and a magnetorheological mounting frame; wherein, The magnetorheological mounting frame is arranged on the free end of the robot, the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, and the real-time adjustment device is connected to the polishing wheel, so that the real-time adjustment device adjusts the position of the polishing wheel, thereby changing the polishing gap of the polishing wheel; The polishing motor is connected to the polishing wheel via the transmission belt, so that the polishing motor controls the polishing wheel to rotate, thereby causing the polishing wheel to process the optical element; The nozzle is arranged on the magnetorheological mounting frame, and the nozzle direction of the nozzle is consistent with the rotation direction of the polishing wheel; The supply system is connected to the nozzle via a pipeline, and the supply system delivers the magnetorheological fluid to the nozzle, so that the polishing wheel processes the optical element using the magnetorheological fluid as a medium; The electromagnet is connected to the real-time adjustment device and is brought close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the electromagnet and changes the stiffness of the magnetorheological fluid; at the same time, the real-time adjustment device adjusts the magnetic field strength and the distance between the electromagnet and the polishing wheel; The sensor module is arranged on the magnetorheological mounting frame, and the laser tracker measures the spatial coordinates of the sensor module through the target sphere.

3. The magnetorheological polishing device based on sensor-adjusted electromagnet according to claim 2, characterized in that: The sensor module includes an acceleration sensor; the laser tracker, the sensor module, the robot and the real-time adjustment device are respectively connected to the control unit to form respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

4. The magnetorheological polishing device based on sensor-adjusted electromagnet according to claim 3, characterized in that: The real-time adjustment device includes a displacement output motor, a lead screw, a support and fixing frame, and a current intensity controller; wherein, the support and fixing frame is arranged on the magnetorheological mounting frame, the displacement output motor is arranged on the support and fixing frame, and the displacement output motor is connected to the lead screw arranged on the support and fixing frame; the electromagnet or the polishing wheel is connected to the nut on the lead screw, so that the lead screw drives the electromagnet or the polishing wheel to move; the current intensity controller is connected to the electromagnet through a wire, and power is supplied to the electromagnet to generate a magnetic field; the current intensity controller is communicatively connected to the control unit, and the control unit sends a control signal to the current intensity controller, and the current intensity controller adjusts the current transmitted to the electromagnet according to the control signal, thereby changing the magnetic field strength of the electromagnet.

5. A magnetorheological polishing method based on magnetic field strength, based on the magnetorheological polishing device based on sensor-adjusted electromagnets according to any one of claims 1 to 4, characterized in that: The following steps are involved: A1: Using the laser tracker to obtain the first coordinate of the sensor module and the second coordinate of the polishing wheel working point; using the coordinate relationship module to calculate the coordinate transformation relationship based on the two coordinates; A2: using the coordinate relationship module, through the coordinate conversion relationship, converting the first theoretical coordinates of the working point of the polishing wheel at different polishing trajectory points into the second theoretical coordinates of the sensor module, and obtaining the theoretical straight-line distance based on the current second theoretical coordinate and the previous second theoretical coordinate; A3: Using the coordinate relationship module to record the measurement results of the sensor module to obtain an actual straight-line distance; the actual straight-line distance and the theoretical straight-line distance are calculated by the coordinate relationship module to obtain a distance error; A4: controlling the magnetorheological processing module to perform fixed-point processing on the test optical element, and obtaining the first conversion relationship through the conversion relationship module; A5: Set a distance error threshold, a control maximum value, and a maximum magnetic field strength; determine processing conditions based on the distance error, the distance difference threshold, and the control maximum value; based on the processing conditions, process the optical element to be processed in combination with the first conversion relationship and the maximum magnetic field strength, and during the processing, perform real-time control on the magnetic field strength of the electromagnet through the real-time control module.

6. The magnetorheological polishing method based on magnetic field intensity according to claim 5, characterized in that: In step A1, the laser tracker obtains the coordinates of no less than four positions on the sensor module through the target sphere, and obtains the first coordinate (x1, y1, z1) by calculation; The laser tracker obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel through the target ball, and then calculates the coordinates of the center point of the polishing wheel (x2, y2, z2). The straight line passing through the center point coordinates is: ； Wherein, (a, b, c) represents the normal vector of the straight line; By solving the following equations, the spatial coordinate corresponding to the minimum value of the Z-axis coordinate is used as the second coordinate (x, y, z): ； Wherein, R represents the radius of the polishing wheel; The coordinate transformation relationship is obtained by combining the second coordinate and the first coordinate: ； Wherein, T represents the coordinate transformation relationship.

7. The magnetorheological polishing method based on magnetic field intensity according to claim 6, characterized in that: In step A2, the theoretical straight-line distance is obtained by the following formula: ； in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

8. The magnetorheological polishing method based on magnetic field intensity according to claim 7, characterized in that: In step A3, the actual straight-line distance is obtained by the following formula: ； Among them, d ri Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; a i-1 represents the acceleration measured by the sensor module at the previous polishing track point, v i-1 represents the speed measured by the sensor module at the previous polishing track point, and t represents the measurement time of the sensor module; the distance error is obtained by the following formula : 。 9. The magnetorheological polishing method based on magnetic field intensity according to claim 8, characterized in that: Step A4 specifically includes the following steps: A41: Under different polishing gaps, the magnetic field strength is individually changed, and processing is performed at different positions of the test optical element. The removal function volume removal rate of each polishing track point is calculated to obtain a third conversion relationship between the removal function volume removal rate and the magnetic field strength: B=F bm (MRR); Wherein, B represents the magnetic field strength, MRR represents the removal function volume removal rate, F bm represents the third conversion relationship; A42: Controlling the polishing wheel to process different positions of the test optical element with different polishing gaps, and calculating the removal function volume removal rate of each polishing trajectory point to obtain a fourth conversion relationship between the removal function volume removal rate and the polishing gap: MRR=F mg (gap); Wherein, gap represents the polishing gap, F mg represents the fourth conversion relationship; A43: Obtain the first conversion relationship according to the third conversion relationship and the fourth conversion relationship: B=F bg (gap)=F bm (F mg (gap)); Among them, F bg Indicates the first conversion relationship.

10. The magnetorheological polishing method based on magnetic field intensity according to claim 9, characterized in that: In step A5, when the polishing wheel is located at the i-th polishing track point, the distance error Distance difference threshold Compare: like , then the current magnetic field strength B i to regulate; like , then for the current magnetic field strength B i To regulate: If the current magnetic field strength B i Less than the maximum magnetic field strength |B max |, the real-time control module is based on the first conversion relationship F bg The current magnetic field strength B i Make adjustments; ； If the current magnetic field strength B i Greater than or equal to the maximum magnetic field strength |B max |, the current magnetic field strength B i Adjust to ±|B max |.

11. A magnetorheological polishing method based on electromagnet position adjustment, based on the magnetorheological polishing device based on sensor-adjusted electromagnet according to any one of claims 1 to 4, characterized in that: The following steps are involved: B1: using the laser tracker to obtain a first coordinate of the sensor module and a second coordinate of the polishing wheel working point; using the coordinate relationship module to calculate a coordinate transformation relationship based on the two coordinates; B2: using the coordinate relationship module to convert the first theoretical coordinates of the working point of the polishing wheel at different polishing track points into the second theoretical coordinates of the sensor module through the coordinate conversion relationship, and obtaining the theoretical straight-line distance based on the current second theoretical coordinate and the previous second theoretical coordinate; B3: Using the coordinate relationship module to record the measurement results of the sensor module to obtain an actual straight-line distance; the actual straight-line distance and the theoretical straight-line distance are calculated by the coordinate relationship module to obtain a distance error; B4: controlling the magnetorheological processing module to perform fixed-point processing on the test optical element, and obtaining the second conversion relationship through the conversion relationship module; B5: Setting a distance error threshold, a control maximum value, and a maximum electromagnet position; determining processing conditions based on the distance error, the distance difference threshold, and the control maximum value; processing the optical element to be processed based on the processing conditions, in combination with the second conversion relationship and the maximum electromagnet position, and performing real-time control of the magnetorheological processing module through the real-time control module during the processing.

12. The magnetorheological polishing method based on electromagnet position adjustment according to claim 11, characterized in that: In step B1, the laser tracker obtains the coordinates of no less than four positions on the sensor module through the target sphere, and obtains the first coordinate (x1, y1, z1) by calculation; The laser tracker obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel through the target ball, and then calculates the coordinates of the center point of the polishing wheel (x2, y2, z2). The straight line passing through the center point coordinates is: ； Wherein, (a, b, c) represents the normal vector of the straight line of the center point coordinates; By solving the following equations, the spatial coordinate corresponding to the minimum value of the Z-axis coordinate is used as the second coordinate (x, y, z): ； Wherein, R represents the radius of the polishing wheel; The coordinate transformation relationship is obtained by combining the second coordinate and the first coordinate: ； Wherein, T represents the coordinate transformation relationship.

13. The magnetorheological polishing method based on electromagnet position adjustment according to claim 12, characterized in that: In step B2, the theoretical straight-line distance is obtained by the following formula: ； in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

14. The magnetorheological polishing method based on electromagnet position adjustment according to claim 13, characterized in that: In step B3, the actual straight-line distance is obtained by the following formula: ； Among them, d ri Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; a i-1 represents the acceleration measured by the sensor module at the previous polishing track point, v i-1 represents the speed measured by the sensor module at the previous polishing track point, Represents the measurement time of the sensor module; the distance error is obtained by the following formula : 。 15. The magnetorheological polishing method based on electromagnet position adjustment according to claim 14, characterized in that: Step B4 includes the following steps: B41: Under different polishing gaps, the position of the electromagnet is changed individually, the test optical element is processed with different polishing gaps, and the removal function volume removal rate of each polishing trajectory point is calculated to obtain a fifth conversion relationship between the removal function volume removal rate and the position of the electromagnet: LT=F tm (MRR); Wherein, LT represents the position of the electromagnet, MRR represents the volume removal rate of the removal function, and F tm represents the fifth conversion relationship; B42: Control the robot to drive the polishing wheel to process different positions of the test optical element with different polishing gaps, and calculate the removal function volume removal rate of each polishing trajectory point to obtain a sixth conversion relationship between the removal function volume removal rate and the polishing gap: MRR=F mg (gap); Wherein, gap represents the polishing gap, F mg represents the sixth conversion relationship; B43: Obtain the second conversion relationship according to the fifth conversion relationship and the sixth conversion relationship, namely: LT=F tg (gap)=F tm (F mg (gap)); Among them, F tg Indicates the second conversion relationship.

16. The magnetorheological polishing method based on electromagnet position adjustment according to claim 15, characterized in that: In step B5, When the polishing wheel is located at the i-th polishing track point, the distance error The distance difference threshold Compare: like , then the current electromagnet position LT is not correct i Make adjustments: like , then the current electromagnet position LT i Make adjustments: If the current electromagnet position LT i Less than the maximum solenoid position |LT max |When the current electromagnet position LT i Control is performed according to the following formula: ； If the current electromagnet position LT i Greater than or equal to the maximum solenoid position |LT max |When the current electromagnet position is LT i Adjust to ±|LT max |.

17. A magnetorheological polishing method based on magnetic field strength and polishing wheel movement, based on the magnetorheological polishing device based on sensor-adjusted electromagnets according to any one of claims 1 to 4, characterized in that: The following steps are involved: C1: using the laser tracker to obtain the first coordinate of the sensor module and the second coordinate of the polishing wheel working point; using the coordinate relationship module to calculate the coordinate transformation relationship based on the two coordinates; C2: using the coordinate relationship module to convert the first theoretical coordinates of the working point of the polishing wheel at different polishing track points into the second theoretical coordinates of the sensor module through the coordinate conversion relationship, and obtaining the theoretical straight-line distance based on the current second theoretical coordinate and the previous second theoretical coordinate; C3: Using the coordinate relationship module to record the measurement results of the sensor module to obtain an actual straight-line distance; the actual straight-line distance and the theoretical straight-line distance are calculated by the coordinate relationship module to obtain a distance error; C4: Setting a distance error threshold, a maximum control value, a maximum electromagnet position, a maximum magnetic field strength, and a maximum polishing gap; determining processing conditions based on the distance error, the distance difference threshold, and the maximum control value; processing the optical element to be processed based on the processing conditions, in combination with the maximum magnetic field strength and the maximum polishing gap, and performing real-time control of the magnetorheological processing module through the real-time control module during the processing.

18. The magnetorheological polishing method based on magnetic field intensity and polishing wheel movement according to claim 17, characterized in that: In step C1, the laser tracker obtains the coordinates of no less than four positions on the sensor module through the target sphere, and obtains the first coordinate (x1, y1, z1) by calculation; The laser tracker obtains the coordinates of no less than 10 different positions on the outer surface of the polishing wheel through the target ball, and then calculates the coordinates of the center point of the polishing wheel (x2, y2, z2). The straight line passing through the center point coordinates is: ； Wherein, (a, b, c) represents the normal vector of the straight line of the center point coordinates; By solving the following equations, the spatial coordinate corresponding to the minimum value of the Z-axis coordinate is used as the second coordinate (x, y, z): ； Wherein, R represents the radius of the polishing wheel; The coordinate transformation relationship is obtained by combining the second coordinate and the first coordinate: ； Wherein, T represents the coordinate transformation relationship.

19. The magnetorheological polishing method based on magnetic field intensity and polishing wheel movement according to claim 18, characterized in that: In step C2, the theoretical straight-line distance is obtained by the following formula: ； in, Indicates the theoretical straight-line distance between the current polishing track point and the previous polishing track point, Indicates the Z coordinate in the current second theoretical coordinate, Indicates the Z coordinate in the previous second theoretical coordinate.

20. The magnetorheological polishing method based on magnetic field intensity and polishing wheel movement according to claim 19, characterized in that: In step C3, the actual straight-line distance is obtained by the following formula: ； Among them, d ri Indicates the actual straight-line distance between the current polishing track point and the previous polishing track point; a i-1 represents the acceleration measured by the sensor module at the previous polishing track point, v i-1 represents the speed measured by the sensor module at the previous polishing track point, and t represents the measurement time of the sensor module; the distance error is obtained by the following formula : 。 21. The magnetorheological polishing method based on magnetic field intensity and polishing wheel movement according to claim 20, characterized in that: In step C4, when the polishing wheel is located at the i-th polishing track point, the distance error The distance difference threshold Compare: like , then the current magnetic field strength and the current polishing gap are not regulated; like , then the current magnetic field strength and the current polishing gap are regulated: If the current magnetic field strength B i Less than the maximum magnetic field strength |B max |, and the current polishing gap gap i Smaller than the maximum polishing gap max |, current magnetic field strength B i and the current polishing gap i They are regulated according to the following formulas: ； Wherein, gap0 is the initial polishing gap of the polishing wheel, r represents the distance between the lowest point of the polishing wheel and the electromagnet, M represents the magnetic moment, and k is the proportional coefficient; If the current magnetic field strength B i Greater than or equal to the maximum magnetic field strength |B max |, and the current polishing gap gap i Greater than or equal to the maximum polishing gap|gap max |, current magnetic field strength B i Adjust to ±|B max |, current polishing gap i Adjust to ±|gap max |.

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