Magnetorheological polishing equipment based on sensing of laser tracker and polishing method of magnetorheological polishing equipment

Abstract

The invention relates to the technical field of magneto-rheological polishing, in particular to magneto-rheological polishing equipment based on sensing of a laser tracker and a polishing method of the magneto-rheological polishing equipment based on sensing of the laser tracker. And real-time constant control over the removal function is achieved through robot pose adjustment, polishing wheel position adjustment or magnet position adjustment. According to the method, measurement equipment such as a force sensor does not need to be calibrated; the device is simple in structure, is not affected by the weight of the magneto-rheological polishing equipment, the operation precision, the operation speed, the posture and other factors, can measure the posture change of the magneto-rheological polishing equipment in the machining process in real time, visually reflects the posture error of the magneto-rheological polishing equipment, and has the advantages of being low in equipment cost and high in measurement precision.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetorheological finishing, and in particular to a magnetorheological finishing device and a finishing method thereof based on laser tracker sensing. Background Art

[0002] Magnetorheological Finishing (MRF) is an advanced optical manufacturing technology developed in recent years. It has many advantages such as a stable removal function, controllable edge effect, small subsurface damage layer, no replication effect, strong shape correction ability, and high processing accuracy. Therefore, magnetorheological finishing technology has received extensive attention in high-precision optical processing. The existing magnetorheological finishing machining centers mainly integrate magnetorheological finishing modules on numerically controlled machine tools. However, there are some deficiencies in numerically controlled machine tools (such as low degrees of freedom, large floor area, high cost, etc.), which limit the deviation of aspherical surfaces and make it difficult to perform precise pose control along the surface normal. In view of these deficiencies of numerically controlled machine tools, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. Six-degree-of-freedom industrial robots have the advantages of high degrees of freedom, small floor area, large processing range, low cost, etc., making up for the deficiencies of numerically controlled machine tools. Therefore, when integrating magnetorheological finishing modules on industrial robots, high-precision machining of large-aperture complex-curved optical elements can theoretically be achieved. However, due to the influence of factors such as machining, assembly, load, trajectory planning, and reduction ratio, the execution accuracy of the end of the industrial robot is relatively low, and the polishing gap changes greatly during the machining process. At the same time, magnetorheological finishing technology is an optical processing technology with a high degree of certainty of the removal function, and has high requirements for changes in the polishing gap during the polishing process. Generally, the change in the polishing gap of a magnetorheological numerical control machining center is within dozens of micrometers (PV < 0.1 mm), while the trajectory accuracy of common commercial industrial robots is generally in the sub-millimeter to millimeter range. This results in a large change in the polishing gap during the machining process, a decrease in the certainty of the removal function, and an impact on the final machining accuracy. Therefore, the motion accuracy of current commercial large six-degree-of-freedom industrial robots often fails to meet the requirements of the magnetorheological finishing technology for changes in the removal function during high-precision polishing.

[0003] In response to the problem of low motion accuracy of industrial robots, the current real-time control scheme based on constant-force grinding and polishing has become a research hotspot, and the force-position control method has become a common method for controlling the constant-force grinding and polishing of robots. A common application method is to place a force sensor between the processing tool and the industrial robot. First, the gravity calibration of the force sensor is performed to ensure the accurate determination of the measurement. The pose error is calculated by measuring the change in force, and then the pose error of the industrial robot is compensated by means of the industrial robot body or other motion compensation mechanisms to achieve constant-force control. The high-efficiency processing of large-aperture optical elements relies on the magnetorheological processing equipment of large-size polishing wheels, and the weight of the magnetorheological processing module of large-size polishing wheels is generally over a hundred kilograms. However, for a magnetorheological processing module weighing over a hundred kilograms, the force change caused by the pose error of the industrial robot is only a few dozen Newtons. When high-precision processing is required, the force needs to be constant at a few Newtons or even a fraction of a Newton, which requires the absolute measurement accuracy of measurement equipment such as force sensors to reach one ten-thousandth, and the force sensor also needs to be in variable-speed and variable-attitude motion. Force sensors that meet these requirements are often extremely expensive, greatly increasing the cost of the equipment. Summary of the Invention

[0004] The purpose of the present invention is to provide a magnetorheological polishing device and its polishing method based on laser tracker sensing to solve the problem that the use of high-precision force sensors will greatly increase the equipment cost.

[0005] To achieve the above purpose, the technical solution of the present invention is realized as follows: A magnetorheological polishing device based on laser tracker sensing, comprising: A polishing platform, on which there are elements to be polished and test polishing elements; A polishing assembly, including an industrial robot and a magnetorheological polishing module. The industrial robot is used to drive the magnetorheological polishing module to move to the position where the test polishing element is located or the position where the element to be polished is located; the magnetorheological polishing module is used to polish the element to be polished or the test polishing element. The magnetorheological polishing module includes a magnetorheological mounting frame, a polishing wheel, a nozzle, a magnet, a liquid pump, and two sets of position adjustment devices. The magnetorheological mounting frame is installed at the tool end of the industrial robot. The polishing wheel and the magnet are respectively installed on the magnetorheological mounting frame through the position adjustment devices. The nozzle is installed on the magnetorheological mounting frame. The liquid pump is arranged on the industrial robot. The liquid pump is used to pump magnetorheological fluid into the nozzle. The nozzle is used to spray magnetorheological fluid onto the polishing wheel. The magnet is used to change the stiffness of the magnetorheological fluid. The polishing wheel is used to polish the test polishing element or the element to be polished. The two sets of position adjustment devices are respectively used to adjust the position of the polishing wheel and the position of the magnet; A laser tracker, whose target ball is installed at the tool end of an industrial robot. The laser tracker is used to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, and convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball; A computer, which is used to calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point. The computer is also used to adjust the posture of the industrial robot when the distance error exceeds the set error range, or adjust the position of the magnet according to the conversion relationship between the magnet position and the polishing gap, or adjust the position of the polishing wheel according to the conversion relationship between the polishing wheel position and the polishing gap, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point.

[0006] Furthermore, each set of position adjustment devices includes a support fixing frame, a ball screw stepping motor, and a connecting plate. The ball screw stepping motor is vertically installed on the magnetorheological mounting frame through the support fixing frame. The nut of the ball screw stepping motor is fixedly connected to the connecting plate. The magnet and the polishing wheel are respectively connected to the corresponding connecting plates.

[0007] Furthermore, the magnetorheological polishing module further includes a polishing wheel driving device. The polishing wheel driving device includes a driving motor, a motor connecting plate, a driving wheel, a driven wheel, and a synchronous belt. The driving motor is installed on the connecting plate. A bearing seat is installed on the connecting plate. A bearing is installed in the bearing seat. The bearing is connected to the polishing wheel. The driven wheel is sleeved on the bearing. The driving wheel is sleeved on the output end of the driving motor. The synchronous belt is tensioned between the driven wheel and the driving wheel.

[0008] A magnetorheological polishing method based on the posture adjustment of an industrial robot, which is realized by using the above-mentioned magnetorheological polishing equipment based on laser tracker perception, and includes the following steps: S1: Establish a measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, and calculate the posture conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball. According to the posture conversion relationship, convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball; S2: Use the magnetorheological polishing equipment to polish the element to be polished, measure the actual spatial coordinates of the target ball at each polishing trajectory point in real time through the laser tracker, and calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point; S3: Judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the posture of the industrial robot at the current polishing trajectory point unchanged; if it exceeds, adjust the posture of the industrial robot through the computer, change the removal function at the current polishing trajectory point, and finally maintain the constancy of the removal function at each polishing trajectory point.

[0009] Furthermore, the distance error , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, and represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point; Set the Z-axis adjustment amount of the industrial robot at the current polishing trajectory point in the computer to , the maximum value of the Z-axis adjustment amount of the industrial robot is , and the set error range is . Let represent the maximum value of the distance error, then: When , keep the pose of the industrial robot at the current polishing trajectory point unchanged; When and , adjust the pose of the industrial robot at the current polishing trajectory point according to the following formula: When and , adjust the pose of the industrial robot at the current polishing trajectory point according to the following formula: .

[0010] Furthermore, the process of establishing the measurement coordinate system of the laser tracker is as follows: Use the laser tracker to measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system respectively. The number of measured points on each axis is not less than 10. Use the line fitting function of the laser tracker to perform linear fitting on the measured points on each axis, and use the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

[0011] Furthermore, the process of using the laser tracker to measure the spatial coordinates of the polishing wheel working point and the target ball when the industrial robot is in different postures is as follows: Set the tool end of the industrial robot to at least 12 postures, and use the industrial robot to drive the polishing wheel to at least 12 different poses; Use the laser tracker to measure the spatial coordinates of the polishing wheel working point and the target ball when the industrial robot is in each pose; The measurement process of the spatial coordinates of the polishing wheel working point is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates, and obtain the center point coordinates of the polishing wheel through the sphere fitting function of the laser tracker , and the straight line passing through the center point of the polishing wheel is: ; wherein, a, b, and c are the normal vectors of the straight line, obtained through the teach pendant of the industrial robot; By solving the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the following system of equations and using them as the spatial coordinates of the working point of the polishing wheel : ; wherein, R represents the radius of the polishing wheel.

[0012] A magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position, realized by using the above magnetorheological polishing equipment based on laser tracker sensing, includes the following steps: S1: Establish a measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, calculate the pose conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball, and convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball according to the pose conversion relationship; S2: At different polishing gaps, change the position of the magnet or the polishing wheel relative to the test polishing element through the position adjustment device, perform fixed-point processing on each processing point of the test polishing element, calculate the volume removal rate of the removal function at each processing point at different polishing gaps, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding magnet positions or polishing wheel positions at different polishing gaps to obtain the conversion relationship between the polishing gap and the magnet position or the conversion relationship between the polishing gap and the polishing wheel position ; wherein, represents the polishing gap corresponding to each volume removal rate of the removal function, LT represents the magnet position, represents the conversion relationship between the polishing gap and the magnet position, LW represents the polishing wheel position, represents the conversion relationship between the polishing gap and the polishing wheel position; S3: Use the magnetorheological polishing equipment to polish the element to be polished, measure the actual spatial coordinates of the target ball at each polishing trajectory point in real time through the laser tracker, and calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point; S4: Determine whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the polishing wheel position and the magnet position at the current polishing trajectory point unchanged; if it exceeds, adjust the magnet position or the polishing wheel position through the computer-controlled position adjustment device to change the removal function at the current polishing trajectory point, and finally maintain the constancy of the removal function at each polishing trajectory point.

[0013] Furthermore, the distance error , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, and represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point; The maximum adjustment amount of the polishing wheel position is set in the computer to , the maximum adjustment amount of the magnet position is set to , and the error range is set to . Let represent the maximum value of the distance error, then: When , keep the polishing wheel position and the magnet position at the current polishing trajectory point unchanged; When and the polishing wheel position at the current polishing trajectory point or the magnet position at the current polishing trajectory point , adjust the polishing wheel position or the magnet position at the current polishing trajectory point according to the following formula: When and the polishing wheel position at the current polishing trajectory point or the magnet position at the current polishing trajectory point , adjust the polishing wheel position or the magnet position at the current polishing trajectory point according to the following formula: ; where represents the set initial position of the polishing wheel, and

[0014] represents the set initial position of the magnet. Furthermore, the process of establishing the measurement coordinate system of the laser tracker is as follows:

[0015] Use the laser tracker to measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system. The number of measured points on each axis is not less than 10. Use the line fitting function of the laser tracker to perform linear fitting on the measured points on each axis, and use the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.Further, the process of using a laser tracker to measure the spatial coordinates of the polishing wheel working point and the spatial coordinates of the target ball when the industrial robot is in different postures is as follows: Set the tool end of the industrial robot to at least 12 postures, and use the industrial robot to drive the polishing wheel to at least 12 different poses; Use a laser tracker to measure the spatial coordinates of the polishing wheel working point and the spatial coordinates of the target ball when the industrial robot is in each pose; The measurement process of the spatial coordinates of the polishing wheel working point is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates, and obtain the center point coordinates of the polishing wheel through the sphere fitting function of the laser tracker , the straight line passing through the center point of the polishing wheel is: ; Among them, a, b, and c are the normal vectors of the straight line, which are obtained through the teach pendant of the industrial robot; By solving the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the following system of equations and taking them as the spatial coordinates of the polishing wheel working point : ; Among them, R represents the radius of the polishing wheel.

[0016] Compared with the prior art, the present invention measures the real-time change of the posture of the magnetorheological polishing equipment during the polishing process through a laser tracker, and realizes the real-time constant control of the removal function by adjusting the posture of the industrial robot, the position of the magnet, or the position of the polishing wheel. This method does not require calibration of measurement devices such as force sensors, and is not affected by factors such as the weight of the magnetorheological polishing equipment, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the posture change of the polishing equipment can be measured in real time, and the posture error of the polishing equipment can be intuitively reflected. It has the advantages of low equipment cost and high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the magnetorheological polishing equipment based on laser tracker perception according to the embodiment of the present invention; Figure 2 is a schematic structural diagram of the magnetorheological polishing module according to the embodiment of the present invention from one perspective; Figure 3 is a schematic structural diagram of the magnetorheological polishing module according to the embodiment of the present invention from another perspective; Figure 4 is a schematic structural diagram of the position adjustment device according to the embodiment of the present invention.

[0018] Reference Numerals: polishing platform 1, element to be polished 101, test polishing element 102, industrial robot 201, magnetorheological mounting bracket 202, polishing wheel 203, magnet 204, nozzle 205, liquid pump 206, support fixing bracket 207, ball screw stepping motor 208, connecting plate 209, drive motor 210, driving wheel 211, driven wheel 212, synchronous belt 213, lead screw 214, guide rail 215, slider 216, nut 217, position adjustment device 218, laser tracker 3, target ball 301, computer 4. Detailed Embodiment

[0019] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be 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 to the present invention.

[0021] Aiming at the deficiencies of the force-position control method based on a force sensor, the present invention proposes a magnetorheological polishing device and its polishing method based on laser tracker perception. By measuring the real-time changes in the pose of the polishing device during the polishing process with a laser tracker, and using different control methods (adjusting the pose of the industrial robot / changing the relative distance between the polishing wheel and the element to be polished or the relative distance between the magnet and the element to be polished), the real-time constancy of the removal function is achieved. This method does not require calibration of measurement devices such as force sensors, is not affected by factors such as the weight of the magnetorheological processing module, the running accuracy, running speed, attitude of the device itself, and other factors, can measure the pose changes of the polishing device in real time during the optical polishing process, intuitively reflect the pose error of the polishing device, and has the advantage of high measurement accuracy.

[0022] The following will describe in detail the maintenance of the constancy of the removal function with specific embodiments.

[0023] In a first aspect, the present embodiment provides a magnetorheological polishing device based on laser tracker perception. The structure of the device is as Figures 1 - 4 shown and includes: A polishing platform 1, on which an element to be polished 101 and a test polishing element 102 are arranged; A polishing component, which includes an industrial robot 201 and a magnetorheological polishing module. The industrial robot 201 is used to drive the magnetorheological polishing module to move to the position where the test polishing element 102 is located or drive the magnetorheological polishing module to move to the position where the element to be polished 101 is located. The magnetorheological polishing module is used to polish the element to be polished 101 or the test polishing element 102. The magnetorheological polishing module includes a magnetorheological mounting frame 202, a polishing wheel 203, a magnet 204, a nozzle 205, a liquid pump 206, two sets of position adjustment devices 218 and a set of polishing wheel driving devices. The magnetorheological mounting frame 202 is installed at the tool end of the industrial robot 201. The polishing wheel driving device is installed on the magnetorheological mounting frame 202 and is used to drive the polishing wheel 203 to rotate to polish the element to be polished 101 or the test polishing element 102. The nozzle 205 is installed on the magnetorheological mounting frame 202 and is used to spray magnetorheological fluid onto the polishing wheel 203. The liquid pump 206 is installed on the industrial robot 201 or arranged on one side of the industrial robot 201. The liquid pump 206 is connected to the nozzle 205 through a pipeline and is used to pump magnetorheological fluid into the nozzle 205. The liquid pump 206 selects the DFLD vertical multi-stage pump of Shanghai Orient Pump Industry Co., Ltd. Two sets of position adjustment devices 218 are respectively installed on the magnetorheological mounting frame 202. One set of position adjustment device 218 is used to adjust the position of the magnet 204, and the magnet 204 is used to change the stiffness of the magnetorheological fluid. The other set of position adjustment device 218 is used to adjust the position of the polishing wheel 203. A laser tracker 3, which is arranged on one side of the polishing platform 1 and is used in cooperation with a target ball 301. The target ball 301 is at the tool end of the industrial robot 201. The laser tracker 3 is used to measure the spatial coordinates of the polishing wheel working point (the polishing wheel working point refers to the lowest point of the polishing wheel when the magnetorheological polishing equipment is in the zero position) of the industrial robot 201 in different postures and the spatial coordinates of the target ball 301, and convert the theoretical spatial coordinates of the set polishing wheel working point into the theoretical spatial coordinates of the target ball 301. A computer 4, which is used to calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball 301 at each polishing trajectory point. The computer 4 is also used to adjust the pose of the industrial robot 201 or adjust the position of the magnet 204 according to the conversion relationship between the position of the magnet 204 and the polishing gap or adjust the position of the polishing wheel 203 according to the conversion relationship between the position of the polishing wheel 203 and the polishing gap when the distance error exceeds the set error range, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point.

[0024] The structures of the two sets of position adjustment devices 218 are the same, and each includes a support fixing frame 207, a ball screw stepper motor 208, and a connecting plate 209. The ball screw stepper motor 208 is vertically installed on the magnetorheological mounting frame 202 through the support fixing frame 207. The nut 217 of the ball screw stepper motor 208 is fixedly connected to the connecting plate 209. The magnet 204 and the polishing wheel 203 are respectively connected to the connecting plates 209 of the two sets of position adjustment devices 218. The magnet 204 and the polishing wheel 203 are driven by the ball screw stepper motors 208 of the two sets of position adjustment devices 218 for position adjustment.

[0025] The polishing wheel driving device includes a driving motor 210, a driving wheel 211, a driven wheel 212, and a synchronous belt 213. The driving motor 210 is installed on the connecting plate 209 of the position adjustment device 218 (for adjusting the position of the polishing wheel 203). A bearing seat is installed on the connecting plate 209, and a bearing is installed in the bearing seat. The bearing is connected to the polishing wheel 203. The driven wheel 212 is sleeved on the bearing, the driving wheel 211 is sleeved on the output end of the driving motor 210, and the synchronous belt 213 is tensioned between the driven wheel 212 and the driving wheel 211. The polishing wheel 203 is driven to rotate by the driving motor 210. Reference can be made to the Chinese patent with the publication date of July 12, 2024 and the publication number of CN118322074A.

[0026] In the embodiment of the present invention, to ensure that the polishing wheel 203 and the magnet 204 can move stably along the lead screw 214 of the ball screw stepper motor 208, it is preferably to install a guide rail 215 on each side of the lead screw 214 on the support fixing frame 228, and the two guide rails 215 are parallel to the lead screw 214. A slider 216 is slidably connected to the two guide rails 215. At this time, the connecting plate 209 is fixedly connected to the nut 217 and the two sliders 216 at the same time. During polishing, the computer 4 sends a control signal to the ball screw stepper motor 208, and the ball screw stepper motor 208 drives the connecting plate 209 to move linearly under the sliding fit of the guide rail 215 and the slider 216.

[0027] It should be noted that there is a strong magnetic phenomenon in the working area where the magnetorheological polishing module is located. The connection of various circuits needs to avoid the working area to prevent the wires from being adsorbed to the magnetorheological polishing module and affecting the normal operation.

[0028] The working principle of the magnetorheological polishing equipment based on laser tracker sensing is as follows: First, use the laser tracker 3 to calibrate the pose conversion relationship between the target ball 301 and the lowest point of the polishing wheel 203; then set the operation control parameters of the magnetorheological polishing equipment; then use the laser tracker 3 and the target ball 301 to measure the pose error of the magnetorheological polishing equipment in the motion state, compare the measured motion pose with the theoretical pose data to obtain the pose error information, calculate the polishing gap change data through the measured motion pose, and then obtain the change data of the removal function. Finally, adjust the pose of the industrial robot 201 or the position of the magnet 204 or the position of the polishing wheel 203 to control the change of the removal function, achieve the desired control parameters, and finally achieve the purpose of keeping the removal function of each polishing point constant.

[0029] In a second aspect, the present embodiment further provides a magnetorheological polishing method based on the pose adjustment of an industrial robot, which is implemented by using the above-mentioned magnetorheological polishing equipment based on laser tracker sensing, and includes the following steps: S1: Establish a measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, and calculate the pose conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball.

[0030] The process of establishing the measurement coordinate system of the laser tracker is as follows: Use the laser tracker to measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system respectively. The number of measured points on each axis shall not be less than 10. Use the line fitting function of the laser tracker (this function is the basic function of the laser tracker) to perform linear fitting on the measured points on each axis, and use the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

[0031] The process of using the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures is as follows: Set the tool end of the industrial robot to at least 12 postures, that is, use the industrial robot to drive the polishing wheel to at least 12 different poses. Use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball in each pose.

[0032] The process of measuring the spatial coordinates of the target ball is: measure the position coordinates of the target ball when the tool end of the industrial robot is in different postures, and the spatial coordinates of the corresponding target ball measured in each posture are .

[0033] The process of measuring the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates. The coordinates of the center point of the polishing wheel can be obtained through the sphere fitting function of the laser tracker. , and the straight line passing through the center point of the polishing wheel is: ; Among them, a, b, and c are the normal vectors of the straight line, which are obtained through the teach pendant of the industrial robot; Since the straight line passes through the working point of the polishing wheel, the spatial coordinates of the working point of the polishing wheel can be obtained by solving the following system of equations , and the spatial coordinates of the working point of the polishing wheel are the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the solution of the system of equations: ; Among them, R is the radius of the polishing wheel.

[0034] Repeat the above measurement process when the tool end of the industrial robot is in different postures to obtain the spatial coordinates of the working point of the polishing wheel corresponding to each posture .

[0035] Calculate the pose transformation relationship T between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball according to the following formula: .

[0036] After obtaining the pose transformation relationship T, the theoretical Z-axis spatial coordinate of the set working point of the polishing wheel can be converted into the theoretical Z-axis spatial coordinate of the target ball according to the pose transformation relationship T.

[0037] S2: Use the magnetorheological polishing equipment to polish the element to be polished. Measure the actual spatial coordinates of the target ball at each polishing trajectory point in real time through the laser tracker, and calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point.

[0038] Continuously measure the spatial coordinates of the target ball during the polishing of the element to be polished, and calculate the distance error between the actual Z-axis spatial coordinate and the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point, represents the error range of the set distance error, represents the maximum value of the distance error.

[0039] S3: Determine whether the distance error of each polishing trajectory point exceeds the set error range; if not, keep the pose of the industrial robot at the current polishing trajectory point unchanged; if it exceeds, adjust the pose of the industrial robot through the computer, change the removal function at the current polishing trajectory point, and finally maintain the constancy of the removal function at each polishing trajectory point.

[0040] Adjust the change of the removal function by adjusting the pose of the industrial robot. During the polishing process of the element to be polished, the laser tracker continuously measures the spatial coordinates of the target ball. If the distance error is within the allowable change error range, that is , then the trajectory error of the magnetorheological polishing equipment meets the high-precision machining requirements, and the industrial robot does not need to adjust its pose; if , the trajectory error of the magnetorheological polishing equipment does not meet the high-precision machining requirements, then it is necessary to adjust the pose of the industrial robot, that is, adjust the running trajectory of the industrial robot on the Z-axis, and the adjustment amount is , and the adjustment direction is judged by comparing the actual Z-axis coordinate value and the theoretical Z-axis coordinate value of the measured target ball. If the actual Z-axis coordinate value of the target ball is less than the theoretical Z-axis coordinate value, the adjustment direction of the industrial robot is upward, that is, the adjustment amount is ; if the actual Z-axis coordinate value of the target ball is greater than the theoretical Z-axis coordinate value, the adjustment direction of the industrial robot is downward, that is, the adjustment amount is .

[0041] To ensure processing safety, set the maximum value of the Z-axis adjustment amount of the industrial robot in the computer to , then: When , keep the pose of the industrial robot at the current polishing trajectory point unchanged; When and , adjust the pose of the industrial robot at the current polishing trajectory point according to the following formula: ; When and , adjust the pose of the industrial robot at the current polishing trajectory point according to the following formula: .

[0042] Calculate the time required to adjust the magnetorheological processing module when the Z-axis adjustment amount of the industrial robot is the maximum value : ; Among them, is the maximum moving speed of the magnetorheological processing module.

[0043] Statistically analyze b data measured by the laser tracker within a seconds to obtain the time taken by the laser tracker to measure a polishing trajectory point ; ; Calculate the minimum movement time between two adjacent polishing trajectory points when the magnetorheological machining module is at the highest moving speed : : ; wherein represents the distance between two adjacent polishing trajectory points

[0044] When generating the machining control program, if , the generated machining control program is appropriate; if , it is necessary to increase the material removal thickness, extend the machining time, and regenerate the machining control program so that the machining dwell time of each polishing trajectory point .

[0045] During the entire machining process, the laser tracker and the target ball are used to continuously measure the pose error of the magnetorheological polishing equipment, and the running trajectory is adjusted in real time through the magnetorheological polishing equipment to achieve the desired control parameters, ensure the stability of the removal function during the machining process, and ultimately achieve the high-precision machining goal

[0046] Compared with the current mainstream real-time control scheme based on force sensors, the present invention measures the real-time changes in the pose of the magnetorheological polishing equipment during the polishing process through a laser tracker, and uses the pose adjustment of the industrial robot to achieve real-time constant control of the removal function. This method does not require calibration of measurement devices such as force sensors, is not affected by factors such as the weight of the magnetorheological polishing equipment, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the pose changes of the polishing equipment can be measured in real time, intuitively reflecting the pose error of the polishing equipment, and having the advantages of low equipment cost and high measurement accuracy

[0047] In a third aspect, the present embodiment further provides a magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position, which is implemented by using the above-mentioned magnetorheological polishing equipment based on laser tracker perception, and includes the following steps S1: Establish the measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, calculate the pose conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball, and convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball according to the pose conversion relationship

[0048] The process of establishing the measurement coordinate system of the laser tracker is as follows Measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system using a laser tracker. The number of measured points on each axis shall not be less than 10. Use the line fitting function of the laser tracker (this function is a basic function of the laser tracker) to perform linear fitting on the measured points on each axis, and take the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

[0049] The process of using a laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures is as follows: Set the tool end of the industrial robot to at least 12 postures, that is, drive the polishing wheel to at least 12 different poses using the industrial robot. Use a laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball in each pose.

[0050] The process of measuring the spatial coordinates of the target ball is as follows: Measure the position coordinates of the target ball when the tool end of the industrial robot is in different postures. The spatial coordinates of the corresponding target ball measured in each posture are .

[0051] The process of measuring the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates. Obtain the center point coordinates of the polishing wheel through the sphere fitting function of the laser tracker , and the straight line passing through the center point of the polishing wheel is: ; where a, b, and c are the normal vectors of the straight line, obtained through the teach pendant of the industrial robot; Since the straight line passes through the working point of the polishing wheel, the spatial coordinates of the working point of the polishing wheel can be obtained by solving the following system of equations , and the spatial coordinates of the working point of the polishing wheel are the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the solution of the system of equations: ; where R is the radius of the polishing wheel.

[0052] Repeat the above measurement process when the tool end of the industrial robot is in different postures to obtain the spatial coordinates of the working point of the polishing wheel corresponding to each posture .

[0053] Calculate the pose transformation relationship T between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball according to the following formula: .

[0054] After obtaining the pose transformation relationship T, the theoretical Z-axis spatial coordinates of the set working point of the polishing wheel can be converted into the theoretical Z-axis spatial coordinates of the target ball according to the pose transformation relationship T.

[0055] S2: At different polishing gaps, change the position of the magnet or the polishing wheel relative to the test polishing element through the position adjustment device, perform fixed-point machining on each machining point of the test polishing element, calculate the volume removal rate of the removal function at each machining point at different polishing gaps, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding magnet positions or polishing wheel positions at different polishing gaps to obtain the conversion relationship between the polishing gap and the magnet position or the conversion relationship between the polishing gap and the polishing wheel position ; where represents the polishing gap corresponding to each volume removal rate of the removal function, LT represents the magnet position, represents the conversion relationship between the polishing gap and the magnet position, LW represents the polishing wheel position, represents the conversion relationship between the polishing gap and the polishing wheel position.

[0056] The present invention realizes the adjustment of the change of the removal function by adjusting the position of the polishing wheel or the magnet relative to the element to be polished.

[0057] The operation for determining the relationship between the position of the magnet relative to the element to be polished and the change of the removal function is as follows: Keep the position of the polishing wheel unchanged (this polishing wheel position is the set initial value in the actual machining process). At different polishing gaps, separately change the position of the magnet relative to the test polishing element, and perform fixed-point machining on each machining point on the surface of the test polishing element by the magnet at different positions for a period of time. Calculate the volume removal rate of the removal function at each machining point at different polishing gaps. Based on the discrete volume removal rates of the removal function and their corresponding magnet position data at different polishing gaps, use the Polyfit instruction of Matlab (this instruction is a basic general instruction of the matlab software) to perform data fitting to obtain the conversion relationship between the polishing gap and the magnet position. This conversion relationship can be characterized as: .

[0058] The operation for determining the relationship between the position of the polishing wheel relative to the element to be polished and the change of the removal function is as follows: Keep the position of the magnet unchanged (this magnet position is the set initial value in the actual processing process). At different polishing gaps, by separately changing the position of the polishing wheel relative to the test polishing element, and performing fixed-point machining at each machining point on the surface of the test polishing element for a period of time at different positions of the polishing wheel, calculate the volume removal rate of the removal function at each machining point at different polishing gaps. Based on the discrete volume removal rates of the removal function and their corresponding polishing wheel position data at different polishing gaps, use the Polyfit instruction in Matlab (this instruction is a basic general instruction in the Matlab software) to perform data fitting to obtain the conversion relationship between the polishing gap and the polishing wheel position. This conversion relationship can be characterized as: 。

[0059] The different polishing gaps mean that the relative distance between the polishing wheel and the magnet remains unchanged, and the distance between the entire magnetorheological polishing module and the element to be polished changes. Separately changing the position of the polishing wheel or the magnet is to change the position of the polishing wheel or the magnet on the basis of each polishing gap.

[0060] For example: Set the polishing gaps to 1 mm and 2 mm. When collecting experimental data, first adjust the polishing gap to 1 mm, then separately change the position of the polishing wheel or the magnet and collect data. After this set of experiments; adjust the polishing gap to 2 mm, then separately change the position of the polishing wheel or the magnet and collect data.

[0061] Since the discrete data volume corresponding to different polishing gaps obtained from the experiment is limited, the actual polishing gap measured during the processing may not be equal to the polishing gap data value obtained from the experiment. The solution is to adopt the closest data, that is, the rounding principle. For example: The conversion relationships between the volume removal rate MRR of the removal function and the polishing wheel position or the magnet position corresponding to the polishing gaps of 1 mm and 2 mm are obtained from the experiment, but the polishing gap during the processing is 1.6 mm. At this time, select the volume removal rate MRR of 2 mm to calculate the conversion relationship between the polishing gap and the polishing wheel position or the magnet position.

[0062] S3: Use the magnetorheological polishing equipment to polish the element to be polished, and use a laser tracker to measure the actual spatial coordinates of the target ball at each polishing trajectory point in real time, and calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point.

[0063] When polishing the element to be polished, continuously measure the spatial coordinates of the target ball and calculate the distance error between the actual Z-axis spatial coordinates and the theoretical Z-axis spatial coordinates of the target ball at each polishing trajectory point , , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point, Indicates the error range of the set distance error Indicates the maximum value of the distance error

[0064] S4: Determine whether the distance error of each polishing trajectory point exceeds the set error range; if not, keep the positions of the polishing wheel and the magnet at the current polishing trajectory point unchanged; if it exceeds, adjust the position of the magnet or the polishing wheel through the computer-controlled position adjustment device to change the removal function of the current polishing trajectory point, and finally maintain the constancy of the removal function of each polishing trajectory point

[0065] Adjust the change of the removal function by adjusting the pose of the industrial robot. During the polishing process of the element to be polished, the laser tracker continuously measures the spatial coordinates of the target ball. If the distance error is within the allowable change error range, that is , then the trajectory error of the magnetorheological polishing equipment meets the requirements of high-precision machining, and the positions of the polishing wheel and the magnet remain unchanged; if , the trajectory error of the magnetorheological polishing equipment does not meet the requirements of high-precision machining. At this time, it is necessary to calculate the polishing gap of the current polishing trajectory point Indicates the set initial polishing gap. According to the conversion relationship between the polishing gap of the current polishing trajectory point and the position of the polishing wheel or according to the conversion relationship between the polishing gap of the current polishing trajectory point and the position of the magnet and the set theoretical removal function volume removal rate, calculate the adjustment amount of the position of the polishing wheel or the magnet, and send it to the position adjustment device through the computer. Finally, regulate the change of the removal function by adjusting the position of the polishing wheel or the magnet to achieve the regulation of the trajectory error of the magnetorheological polishing equipment

[0066] Since the change amount of the operating pose error of the magnetorheological polishing equipment is small, the change of can be regarded as the change of the polishing gap

[0067] To ensure processing safety and that the position of the magnet or the polishing wheel does not affect processing, set the maximum adjustment amount of the polishing wheel position in the computer to and the maximum adjustment amount of the magnet position to , then When , keep the position of the polishing wheel and the position of the magnet at the current polishing trajectory point unchanged When and the position of the polishing wheel at the current polishing trajectory point or the position of the magnet When, the position of the polishing wheel at the current polishing trajectory point or the position of the magnet at the current polishing trajectory point is adjusted according to the following formula: ; ; When and the position of the polishing wheel at the current polishing trajectory point or the position of the magnet at the current polishing trajectory point When, the position of the polishing wheel at the current polishing trajectory point or the position of the magnet at the current polishing trajectory point is adjusted according to the following formula: ; ; Wherein, represents the set initial position of the polishing wheel, represents the set initial position of the magnet.

[0068] Calculate the adjustment amount of the polishing wheel position when it is the maximum value or the adjustment amount of the magnet position when it is the maximum value When, the time required to control the magnetorheological processing module or ; Wherein, is the maximum moving speed of the position adjusting device.

[0069] Statistically analyze b data measured by the laser tracker within a seconds to obtain the time for the laser tracker to measure a polishing trajectory point; ; Calculate the minimum moving time between two adjacent polishing trajectory points under the maximum moving speed of the magnetorheological processing module: ; Wherein, represents the distance between two adjacent polishing trajectory points.

[0070] When generating the processing control program, if , the generated processing control program is appropriate; if , it is necessary to increase the material removal thickness, extend the processing time, and regenerate the processing control program so that the processing dwell time of each polishing trajectory point.

[0071] During the entire processing, a laser tracker and a target ball are used to continuously measure the pose error of the magnetorheological polishing equipment, and the running trajectory is adjusted in real time through the magnetorheological polishing equipment to achieve the desired control parameters, ensure the stability of the removal function during the processing, and finally achieve the high-precision processing goal.

[0072] Compared with the current mainstream real-time control scheme based on force sensors, in the present invention, the real-time changes in the pose of the magnetorheological polishing equipment during the polishing process are measured by a laser tracker, and the real-time constant control of the removal function is achieved by adjusting the magnet position or the polishing wheel position. This method does not require calibration of measurement devices such as force sensors, and is not affected by the weight of the magnetorheological polishing equipment, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the pose changes of the polishing equipment can be measured in real time, intuitively reflecting the pose error of the polishing equipment, and having the advantages of low equipment cost and high measurement accuracy.

[0073] It should be understood that various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitations are imposed herein.

[0074] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A magnetorheological polishing device based on laser tracker sensing, characterized in that, Comprising: A polishing platform, on which an element to be polished and a test polishing element are arranged; A polishing assembly, including an industrial robot and a magnetorheological polishing module. The industrial robot is used to drive the magnetorheological polishing module to move to the position where the test polishing element is located or the position where the element to be polished is located. The magnetorheological polishing module is used to polish the element to be polished or the test polishing element. The magnetorheological polishing module includes a magnetorheological mounting frame, a polishing wheel, a nozzle, a magnet, a liquid pump and two sets of position adjusting devices. The magnetorheological mounting frame is mounted on the tool end of the industrial robot. The polishing wheel and the magnet are respectively mounted on the magnetorheological mounting frame through the position adjusting devices. The nozzle is mounted on the magnetorheological mounting frame. The liquid pump is arranged on the industrial robot or on one side of the industrial robot. The liquid pump is used to pump magnetorheological fluid into the nozzle. The nozzle is used to spray magnetorheological fluid onto the polishing wheel. The magnet is used to change the stiffness of the magnetorheological fluid. The polishing wheel is used to polish the test polishing element or the element to be polished. The two sets of position adjusting devices are respectively used to adjust the position of the polishing wheel and the position of the magnet; A laser tracker, the target ball of which is mounted on the tool end of the industrial robot. The laser tracker is used to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, and convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball; A computer, which is used to calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point, and is also used to adjust the pose of the industrial robot or adjust the position of the magnet according to the conversion relationship between the magnet position and the polishing gap or adjust the position of the polishing wheel according to the conversion relationship between the polishing wheel position and the polishing gap when the distance error exceeds the set error range, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point.

2. The magnetorheological polishing equipment based on laser tracker sensing according to claim 1, wherein Each set of position adjusting devices includes a support fixing frame, a ball screw stepping motor and a connecting plate. The ball screw stepping motor is vertically mounted on the magnetorheological mounting frame through the support fixing frame. The nut of the ball screw stepping motor is fixedly connected with the connecting plate. The magnet and the polishing wheel are respectively connected to the corresponding connecting plates.

3. The magnetorheological polishing device based on laser tracker sensing according to claim 1, characterized in that, The magnetorheological polishing module further includes a polishing wheel driving device. The polishing wheel driving device includes a driving motor, a motor connecting plate, a driving wheel, a driven wheel and a synchronous belt. The driving motor is mounted on the connecting plate. A bearing seat is mounted on the connecting plate. A bearing is mounted in the bearing seat. The bearing is connected with the polishing wheel. The driven wheel is sleeved on the bearing. The driving wheel is sleeved on the output end of the driving motor. The synchronous belt is tensioned between the driven wheel and the driving wheel.

4. A magnetorheological finishing method based on the pose adjustment of an industrial robot, which is realized by using the magnetorheological finishing equipment based on laser tracker perception described in any one of claims 1-3, and is characterized in that Including the following steps: S1: Establish a measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, calculate the pose conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball, and convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball according to the pose conversion relationship; S2: Use a magnetorheological finishing equipment to finish the element to be polished. Measure the actual spatial coordinates of the target ball at each polishing trajectory point in real time with a laser tracker, and calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point. S3: Determine whether the distance error at each polishing trajectory point exceeds the set error range. If it does not exceed, keep the pose of the industrial robot at the current polishing trajectory point unchanged. If it exceeds, adjust the pose of the industrial robot through a computer, change the removal function at the current polishing trajectory point, and finally maintain the constancy of the removal function at each polishing trajectory point.

5. The magnetorheological polishing method based on the pose adjustment of an industrial robot according to claim 4, wherein Distance error , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point; Set the Z-axis adjustment amount of the current polishing trajectory point of the industrial robot in the computer to be , the maximum value of the Z-axis adjustment amount of the industrial robot is , set the error range to be , represents the maximum value of the distance error, then: When the pose of the industrial robot at the current polishing trajectory point remains unchanged; When and At this time, adjust the pose of the industrial robot at the current polishing trajectory point according to the following formula: ； When and At this time, adjust the pose of the industrial robot at the current polishing trajectory point according to the following formula: 。 6. The magnetorheological polishing method based on the pose adjustment of an industrial robot according to claim 4, wherein The process of establishing the measurement coordinate system of the laser tracker is as follows: Use the laser tracker to measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system respectively. The number of measured points on each axis is not less than 10. Use the line fitting function of the laser tracker to perform linear fitting on the measured points on each axis, and use the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

7. The magnetorheological polishing method based on the pose adjustment of an industrial robot according to claim 4, wherein The process of using the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different poses is as follows: Set the tool end of the industrial robot to at least 12 poses, and use the industrial robot to drive the polishing wheel to at least 12 different poses. Use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in each pose. The process of measuring the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates, and obtain the coordinates of the center point of the polishing wheel through the ball fitting function of the laser tracker , and the straight line passing through the center point of the polishing wheel is: ； Among them, a, b, and c are the normal vectors of the straight line, which are obtained through the teach pendant of the industrial robot. Solve the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the following system of equations and use them as the spatial coordinates of the working point of the polishing wheel : ； Among them, R represents the radius of the polishing wheel.

8. A magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position, which is realized by using the magnetorheological polishing equipment based on laser tracker perception described in any one of claims 1-3, and is characterized in that, It includes the following steps: S1: Establish the measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different poses, calculate the pose conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball, and convert the theoretical spatial coordinates of the set working point of the polishing wheel into the theoretical spatial coordinates of the target ball according to the pose conversion relationship. S2: At different polishing clearances, change the positions of the magnet or the polishing wheel relative to the test polishing element through the position adjustment device, perform fixed-point machining on each machining point of the test polishing element, calculate the volume removal rate of the removal function at each machining point at different polishing clearances, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding magnet positions or polishing wheel positions at different polishing clearances to obtain the conversion relationship between the polishing clearance and the magnet position or the conversion relationship between the polishing clearance and the polishing wheel position ; where represents the polishing clearance corresponding to each volume removal rate of the removal function, LT represents the magnet position, represents the conversion relationship between the polishing clearance and the magnet position, LW represents the polishing wheel position, represents the conversion relationship between the polishing clearance and the polishing wheel position; S3: Use a magnetorheological finishing equipment to finish the element to be polished. Measure the actual spatial coordinates of the target ball at each polishing trajectory point in real time with a laser tracker, and calculate the distance error between the actual spatial coordinates and the theoretical spatial coordinates of the target ball at each polishing trajectory point. S4: Determine whether the distance error at each polishing trajectory point exceeds the set error range. If it does not exceed, keep the positions of the polishing wheel and the magnet at the current polishing trajectory point unchanged. If it exceeds, control the position adjustment device through a computer to adjust the position of the magnet or the position of the polishing wheel, change the removal function at the current polishing trajectory point, and finally maintain the constancy of the removal function at each polishing trajectory point.

9. The magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position according to claim 8, characterized in that Distance error , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point; The maximum adjustment amount for setting the position of the polishing wheel in the computer is , and the maximum adjustment amount for setting the position of the magnet is , and the set error range is , represents the maximum value of the distance error, then: When maintain the polishing wheel position and magnet position of the current polishing trajectory point unchanged; ​ When and the polishing wheel position of the current polishing trajectory point or the magnet position of the current polishing trajectory point is reached, adjust the polishing wheel position of the current polishing trajectory point or the magnet position of the current polishing trajectory point according to the following formula: ； ； When and the position of the polishing wheel at the current polishing trajectory point or the position of the magnet at the current polishing trajectory point is the case, adjust the position of the polishing wheel at the current polishing trajectory point or the position of the magnet at the current polishing trajectory point according to the following formula: ； ； Among them, represents the initial position of the set polishing wheel, represents the initial position of the set magnet.

10. The magnetorheological polishing method based on adjusting according to the position of the magnet or the position of the polishing wheel as claimed in claim 8, wherein, The process of establishing the measurement coordinate system of the laser tracker is as follows: Measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system using a laser tracker. The number of measured points on each axis is not less than 10. Use the line fitting function of the laser tracker to perform linear fitting on the measured points on each axis, and take the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

11. The magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position according to claim 8, characterized in that, The process of measuring the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures using a laser tracker is as follows: Set the tool end of the industrial robot to at least 12 postures, and use the industrial robot to drive the polishing wheel to at least 12 different poses; Use a laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in each pose; The measurement process of the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates, and obtain the coordinates of the center point of the polishing wheel through the ball fitting function of the laser tracker , the straight line passing through the center point of the polishing wheel is: ； Among them, a, b, and c are the normal vectors of the straight line, which are obtained through the teach pendant of the industrial robot; By solving the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the following system of equations and taking them as the spatial coordinates of the working point of the polishing wheel : ； Among them, R represents the radius of the polishing wheel.

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