Magnetorheological polishing system based on sensing of laser tracker and polishing method thereof

Abstract

The invention relates to the field of magneto-rheological polishing, in particular to a magneto-rheological polishing system based on sensing of a laser tracker and a polishing method of the magneto-rheological polishing system based on sensing of the laser tracker. Real-time constant control over the removal function is achieved through actuator output displacement adjustment or liquid pump height adjustment or nozzle position adjustment; or a removal function corresponding to the polishing gap of each polishing track point is calculated and serves as a machining parameter of next machining, so that the removal function change of each polishing track point conforms to the removal function caused by the actual polishing gap change. Measurement equipment does not need to be calibrated, influences of the weight of the magneto-rheological polishing system, the running precision of the equipment, the running speed, the posture and other factors are avoided, the posture change of the polishing system can be measured in real time in the optical polishing process, the posture error of the polishing system is visually reflected, and the precision of the polishing system is improved. The device has the advantages of low equipment cost and high measurement precision.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetorheological polishing, and in particular to a magnetorheological polishing system based on laser tracker sensing and a polishing method thereof. 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 copying effect, strong shaping ability, and high machining accuracy. Therefore, the magnetorheological polishing technology has received extensive attention in high-precision optical processing. The existing magnetorheological polishing machining centers mainly integrate the magnetorheological polishing module on a numerically controlled machine tool. However, some deficiencies of the numerically controlled machine tool (such as low degrees of freedom, large floor area, high cost, etc.) limit the deviation of the aspherical surface and it is difficult to perform precise pose control along the surface normal. In view of these deficiencies of the numerically controlled machine tool, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. The six-degree-of-freedom industrial robot has the advantages of high degrees of freedom, small floor area, large processing range, low cost, etc., making up for the deficiencies of the numerically controlled machine tool. Therefore, when integrating the magnetorheological polishing module on an industrial robot, in theory, high-precision machining of large-aperture complex surface optical elements can be achieved. However, due to the influence of factors such as machining, assembly, load, trajectory planning, and reduction ratio, the execution accuracy at the end of the industrial robot is relatively low, and the polishing gap changes greatly during the machining process. At the same time, the magnetorheological polishing technology is an optical processing technology with a high degree of certainty of the removal function, and has high requirements for the change of the polishing gap during the polishing process. Generally, the change of the polishing gap in 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 leads to a large change in the polishing gap during the machining process, reducing the certainty of the removal function and affecting 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 polishing technology for the change of the removal function during high-precision polishing.

[0003] Aiming at 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. Among them, the force-position control method has become a common robot constant-force regulation grinding and polishing control method. A common application method is to place a force sensor between the processing tool and the industrial robot. First, gravity calibration is performed on the force sensor to ensure accurate 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-diameter 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. During high-precision processing, the force needs to be kept 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. Moreover, the force sensor also needs to be in a state of variable speed and variable pose movement, and 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 system and its polishing method based on laser tracker perception 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 system based on laser tracker perception, 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, an actuator group, and a supply device. One end of the actuator group is connected to the magnetorheological mounting frame, and the other end of the actuator group is connected to the tool end of the industrial robot. The polishing wheel and the magnet are respectively installed on the magnetorheological mounting frame. The nozzle is installed on the magnetorheological mounting frame through a nozzle adjustment seat. The nozzle adjustment seat is used to adjust the position of 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 supply device is arranged on one side of the polishing platform and is used to pump magnetorheological fluid into the nozzle; A laser tracker, with its target ball 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 Z-axis spatial coordinate of the set working point of the polishing wheel into the theoretical Z-axis spatial coordinate of the target ball; A computer, which is used to 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. The computer is also used to, when the distance error exceeds the set error range, adjust the output displacement of the actuator group according to the conversion relationship between the output displacement of the actuator group and the polishing gap, or adjust the height of the supply device according to the conversion relationship between the height of the liquid pump and the polishing gap, or adjust the position of the nozzle according to the conversion relationship between the nozzle 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; or, the computer is used to calculate the removal function of each polishing trajectory point according to the conversion relationship between the removal function and the polishing gap, and input it as a new processing parameter into the industrial robot control instruction generation program, so that the change of the removal function at each polishing trajectory point is consistent with the removal function caused by the actual change of the polishing gap.

[0006] Furthermore, the supply device includes a liquid pump, a mounting bracket, a mounting plate, a linear guide rail and a ball screw stepping motor; wherein, the linear guide rail and the ball screw stepping motor are respectively vertically installed on the mounting bracket, and the linear guide rails are distributed on both sides of the ball screw stepping motor. The liquid pump is installed on the mounting plate, and the mounting plate is respectively connected to the slider of the linear guide rail and the nut of the ball screw stepping motor.

[0007] Furthermore, the nozzle is installed on the magnetorheological mounting frame through a nozzle adjusting seat, and the position of the nozzle relative to the polishing wheel is adjusted through the nozzle adjusting seat; the nozzle adjusting seat includes a fixed frame, a nozzle adjusting motor, a pushing plate, a nozzle mounting frame and an arc guide rail; wherein, the fixed frame is installed on the magnetorheological mounting frame, the nozzle adjusting motor and the arc guide rail are respectively installed on the fixed frame, the pushing plate is installed at the output end of the nozzle adjusting motor, the nozzle mounting frame is respectively connected to the pushing plate and the slider of the arc guide rail, and the nozzle is installed on the nozzle mounting frame.

[0008] Furthermore, the magnetorheological polishing module further includes a polishing wheel driving device, and 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, and the synchronous belt is tensioned between the driven wheel and the driving wheel.

[0009] A magnetorheological polishing method based on actuator adjustment, which is realized by using the above-mentioned magnetorheological polishing system 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 polishing wheel working points 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 polishing wheel working points and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinate of the set polishing wheel working point into the theoretical Z-axis spatial coordinate of the target ball; S2: At different polishing clearances, by changing the output displacement of the actuator group, 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 under different polishing clearances, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding actuator group output displacements under different polishing clearances to obtain the conversion relationship between the polishing clearance and the actuator group output displacement ; where, represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the output displacement of the actuator group, represents the conversion relationship between the polishing clearance and the actuator group output displacement; S3: Use the magnetorheological polishing system to polish the element to be polished. Through the laser tracker, measure the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point in real time, 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; S4: Judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the output displacement of the actuator group at the current polishing trajectory point unchanged; if it exceeds, adjust the output displacement of the actuator group 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.

[0010] Further, the 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 maximum adjustment amount of the output displacement of the actuator group in the computer to be , set the error range to be , represents the maximum value of the distance error, then: When , keep the output displacement of the actuator group at the current polishing trajectory point unchanged; When and the output displacement of the actuator group at the current polishing trajectory point , adjust the output displacement of the actuator group at the current polishing trajectory point according to the following formula: ; When and the output displacement of the actuator group at the current polishing trajectory point is, the output displacement of the actuator group at the current polishing trajectory point is adjusted according to the following formula : ; wherein, represents the set initial output displacement of the actuator group.

[0011] 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.

[0012] Furthermore, the process of using the 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 the 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 , 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, 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 using them as the spatial coordinates of the polishing wheel working point : ; wherein, R represents the radius of the polishing wheel.

[0013] A magnetorheological polishing method based on the height adjustment of a liquid pump, which is realized by using the above-mentioned magnetorheological polishing system based on laser tracker perception, 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 polishing wheel working points 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 polishing wheel working points and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinate of the set polishing wheel working point into the theoretical Z-axis spatial coordinate of the target ball; S2: At different polishing clearances, by changing the height of the liquid pump, 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 under different polishing clearances, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding liquid pump heights under different polishing clearances to obtain the conversion relationship between the polishing clearance and the liquid pump height ; where, represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the height of the liquid pump, represents the conversion relationship between the polishing clearance and the liquid pump height; S3: Use the magnetorheological polishing system to polish the element to be polished. Through the laser tracker, measure the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point in real time, 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; S4: Determine whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the height of the liquid pump at the current polishing trajectory point unchanged; if it exceeds, adjust the height of the liquid pump by controlling the ball screw stepper motor 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.

[0014] Further, the 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 maximum adjustment amount of the liquid pump height in the computer to , and set the error range to , represents the maximum value of the distance error, then: When , keep the height of the liquid pump at the current polishing trajectory point unchanged; When and the height of the liquid pump at the current polishing trajectory point , adjust the height of the liquid pump at the current polishing trajectory point according to the following formula: ; When and the liquid pump height of the current polishing trajectory point When, the liquid pump height of the current polishing trajectory point is adjusted according to the following formula as follows: ; wherein, represents the set initial height of the liquid pump.

[0015] 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.

[0016] Furthermore, the process of using the 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 the 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 , 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, which are obtained through the teach pendant of the industrial robot; Obtain 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 polishing wheel working point : ; wherein, R represents the radius of the polishing wheel.

[0017] A magnetorheological polishing method based on nozzle position adjustment is realized by using the above-mentioned magnetorheological polishing system based on laser tracker sensing, 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 points 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 points of the polishing wheel and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinates of the set working points of the polishing wheel into the theoretical Z-axis spatial coordinates of the target ball; S2: At different polishing clearances, by changing the nozzle position, 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 under different polishing clearances, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding nozzle positions under different polishing clearances to obtain the conversion relationship between the polishing clearance and the nozzle position ; where represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the nozzle position, represents the conversion relationship between the polishing clearance and the nozzle position; S3: Use the magnetorheological polishing system to polish the element to be polished. Through the laser tracker, real-time measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point, 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; S4: Judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the nozzle position at the current polishing trajectory point unchanged; if it exceeds, adjust the nozzle position by controlling the nozzle adjustment motor 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.

[0018] Further, the distance error , represents the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinates of the target ball at each polishing trajectory point; Set the maximum adjustment amount of the nozzle position in the computer to be , set the error range to be , represents the maximum value of the distance error, then: When , keep the nozzle position at the current polishing trajectory point unchanged; When and the nozzle position at the current polishing trajectory point , adjust the nozzle position at the current polishing trajectory point according to the following formula: ; When And the nozzle position of the current polishing trajectory point When, the nozzle position of the current polishing trajectory point is adjusted according to the following formula : ; Wherein, represents the set initial position of the nozzle.

[0019] 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.

[0020] Furthermore, the process of using the 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 the 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: ; Wherein, 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 using them as the spatial coordinates of the polishing wheel working point : ; Wherein, R represents the radius of the polishing wheel.

[0021] A magnetorheological polishing method based on removal function adjustment, which is realized by using the above-mentioned magnetorheological polishing system based on laser tracker perception, 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 points 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 points of the polishing wheel and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinate of the set working point of the polishing wheel into the theoretical Z-axis spatial coordinate of the target ball; S2: Perform fixed-point machining on each machining point of the test polishing element at different polishing gaps, calculate the volume removal rate of the removal function at each machining point under different polishing gaps, and perform data fitting on the discrete volume removal rates of the removal functions and their corresponding removal functions under different polishing gaps to obtain the conversion relationship between the polishing gap and the removal function ; where, represents the polishing gap corresponding to each volume removal rate of the removal function, represents the removal function, represents the conversion relationship between the polishing gap and the removal function; S3: Use the magnetorheological polishing system to polish the element to be polished. Real-time measure the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point through the laser tracker, 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 ; where, the 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; S4: Set the error range in the computer as , represents the maximum value of the distance error, and judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, calculate the removal function corresponding to the polishing trajectory point according to ; if it exceeds, let the distance error , and calculate the removal function corresponding to the polishing trajectory point according to ; Input the removal function corresponding to each polishing trajectory point as the new machining parameter into the industrial robot control instruction generation program, so that the change of the removal function at each polishing trajectory point is consistent with the removal function caused by the actual polishing gap change.

[0022] Further, 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 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.

[0023] Furthermore, 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 , 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 equations and use them as the spatial coordinates of the polishing wheel working point : ; Among them, R represents the radius of the polishing wheel.

[0024] Compared with the prior art, the present invention measures the real-time change of the pose of the magnetorheological polishing system during the polishing process through a laser tracker, and uses the output displacement adjustment of the actuator or the height adjustment of the liquid pump or the nozzle position adjustment to realize the real-time constant control of the removal function; or calculates the removal function corresponding to the polishing gap of each polishing trajectory point, and inputs it as a new processing parameter into the industrial robot control instruction generation program, so that the change of the removal function at each polishing trajectory point is consistent with the removal function caused by the actual polishing gap change, realizing the deterministic processing 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 system, the running accuracy of the equipment itself, the running speed, the posture, and other factors, can measure the pose change of the polishing system in real time during the optical polishing process, intuitively reflect the pose error of the polishing system, and has the advantages of low equipment cost and high measurement accuracy. Description of the Drawings

[0025] Figure 1 Schematic structural diagram of the magnetorheological polishing system based on laser tracker sensing according to an embodiment of the present invention from one perspective; Figure 2 Schematic structural diagram of the magnetorheological polishing system based on laser tracker sensing according to an embodiment of the present invention from another perspective; Figure 3 Schematic structural diagram of the actuator according to an embodiment of the present invention; Figure 4 Schematic structural diagram of the supply device according to an embodiment of the present invention; Figure 5 Schematic structural diagram of the nozzle adjustment seat according to an embodiment of the present invention.

[0026] 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, drive motor 206, driving pulley 207, driven pulley 208, synchronous belt 209, transition plate 210, cylinder block 211, chamber A 212, chamber B 213, oil scraping ring 214, connecting plate 215, moving piston 216, liquid pump 217, mounting bracket 218, mounting plate 219, linear guide 220, ball screw stepping motor 221, fixing bracket 222, nozzle adjustment motor 223, pushing plate 224, nozzle mounting bracket 225, arc guide 226, actuator group 227, nozzle adjustment seat 228, laser tracker 3, target ball 301, computer 4. Detailed implementation manners

[0027] Hereinafter, 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.

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, 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, but not to limit the present invention.

[0029] In view of the deficiencies of the force-position control method based on force sensors, the present invention proposes a magnetorheological polishing system and a polishing method based on laser tracker sensing. By measuring the real-time changes in the pose of the polishing system during the polishing process with a laser tracker, different control methods (actuator output displacement adjustment / liquid pump height adjustment / nozzle position adjustment) are used to achieve real-time constancy of the removal function; or calculate the removal function corresponding to the polishing gap at each polishing trajectory point and input it as new processing parameters into the industrial robot control instruction generation program, so that the change in the removal function at each polishing trajectory point matches the removal function caused by the actual change in the polishing gap, realizing deterministic processing 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 processing module, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the real-time changes in the pose of the polishing system can be measured, intuitively reflecting the pose error of the polishing system, and having the advantage of high measurement accuracy.

[0030] The following uses specific embodiments to elaborate in detail on maintaining the constancy of the removal function.

[0031] In a first aspect, the present embodiment provides a magnetorheological polishing system based on laser tracker sensing, and the structure of the magnetorheological polishing system is as Figures 1-5 shown, including: A polishing platform 1, on which a component to be polished 101 and a test polishing component 102 are arranged; A polishing assembly, 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 component 102 is located or drive the magnetorheological polishing module to move to the position where the component to be polished 101 is located; the magnetorheological polishing module is used to polish the component to be polished 101 or the test polishing component 102. The magnetorheological polishing module includes a magnetorheological mounting frame 202, a polishing wheel 203, a magnet 204, a nozzle 205, an actuator group 227, a nozzle adjustment seat 228, a supply device, and a polishing wheel driving device. One end of the actuator group 227 is connected to the magnetorheological mounting frame 202, and the other end of the actuator group 227 is connected to the tool end of the industrial robot 201. The actuator group 227 is used to adjust the polishing gap; the magnetorheological mounting frame 202 is installed at the tool end of the industrial robot 201, and 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 component to be polished 101 or the test polishing component 102; the nozzle 205 is installed on the magnetorheological mounting frame 202 through the nozzle adjustment seat 228 and is used to spray magnetorheological fluid onto the polishing wheel 203. The magnet 204 is used to change the stiffness of the magnetorheological fluid, and the nozzle adjustment seat 228 is used to adjust the position of the nozzle 205; the supply device is arranged on one side of the polishing platform and is used to pump magnetorheological fluid into the nozzle 205; A laser tracker 3 is provided 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 working point of the polishing wheel (the working point of the polishing wheel refers to the lowest point of the polishing wheel when the magnetorheological polishing system is at zero) of the industrial robot 201 in different postures and the spatial coordinates of the target ball 301, and convert the theoretical Z-axis spatial coordinate of the set working point of the polishing wheel into the theoretical Z-axis spatial coordinate of the target ball 301; A computer 4 is used to calculate the distance error between the actual Z-axis spatial coordinate and the theoretical Z-axis spatial coordinate of the target ball 301 at each polishing trajectory point. The computer 4 is also used to, when the distance error exceeds the set error range, adjust the output displacement of the actuator group 227 according to the conversion relationship between the output displacement of the actuator group 227 and the polishing gap, or adjust the height of the supply device according to the conversion relationship between the height of the liquid pump and the polishing gap, or adjust the position of the nozzle 205 according to the conversion relationship between the position of the nozzle 205 and the polishing gap, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point; alternatively, the computer 4 is used to calculate the removal function of each polishing trajectory point according to the conversion relationship between the removal function and the polishing gap, and input it as a new processing parameter into the industrial robot 201 control instruction generation program, so that the change of the removal function at each polishing trajectory point conforms to the removal function caused by the actual change of the polishing gap.

[0032] The polishing wheel driving device includes a driving motor 206, a driving pulley 207, a driven pulley 208, and a synchronous belt 209. The driving motor 206 is installed on the magnetorheological mounting frame 202. A bearing seat is installed on the magnetorheological mounting frame 202. A bearing is installed in the bearing seat. The bearing is connected to the polishing wheel 203. The driven pulley 208 is sleeved on the bearing. The driving pulley 207 is sleeved on the output end of the driving motor 206. The synchronous belt 209 is tensioned between the driven pulley 208 and the driving pulley 207. The polishing wheel 203 is driven to rotate by the driving motor 206. Reference can be made to the Chinese patent with the publication date of July 12, 2024 and the publication number of CN118322074A.

[0033] The actuator group 227 consists of two cascaded high-frequency actuators, that is, one high-frequency actuator is installed on the output end of the other high-frequency actuator, so that the total output displacement of the actuator group 227 is the sum of the output displacements of the two high-frequency actuators. In the embodiment of the present invention, the high-frequency actuator preferably adopts the SG model hydrostatic linear cylinder of Jilin Huakong Test Instrument Co., Ltd. The structures of the two high-frequency actuators are the same, and both include a transition plate 210, a cylinder block 211, an A chamber 212, a B chamber 213, an oil scraper ring 214, a connecting plate 215, and a moving piston 216. The transition plate 210 is used to connect the tool end of the industrial robot 201 to the cylinder block 211. The A chamber 212 and the B chamber 213 are used to control the inflow and outflow of hydraulic oil. The oil scraper ring 214 is used to prevent the hydraulic oil from flowing out of the cylinder block 211. The moving piston 216 is used for position output. The connecting plate 215 is used to connect the moving piston 216 to the magnetorheological polishing module or another high-frequency actuator, and then output displacement to the magnetorheological polishing module or another high-frequency actuator.

[0034] The supply device includes a liquid pump 217, a mounting bracket 218, a mounting plate 219, a linear guide rail 220, and a ball screw stepping motor 221. Among them, the linear guide rail 220 and the ball screw stepping motor 221 are respectively vertically installed on the mounting bracket 218, and the linear guide rail 220 is distributed on both sides of the ball screw stepping motor 221. The liquid pump 217 is installed on the mounting plate 219. The mounting plate 219 is respectively connected to the slider of the linear guide rail 220 and the nut of the ball screw stepping motor 221. The ball screw stepping motor 221 drives the liquid pump 217 to vertically lift, and adjusts the height of the liquid pump 217 relative to the polishing wheel 203. The liquid pump 217 selects the CFLC vertical multistage pump of Shanghai Dongfang Pump Industry Co., Ltd.

[0035] The nozzle adjustment seat 228 includes a fixed frame 222, a nozzle adjustment motor 223, a push plate 224, a nozzle mounting frame 225, and an arc guide rail 226. The fixed frame 222 is installed on the magnetorheological mounting frame 202. The fixed frame 222 is of an L-shaped structure. The nozzle adjustment motor 223 and the arc guide rail 226 are respectively installed on two perpendicular parts of the fixed frame 222, and the length direction of the arc guide rail 226 is the telescopic direction of the nozzle adjustment motor 223. The push plate 224 is installed on the output end of the nozzle adjustment motor 223. One end of the nozzle mounting frame 225 is respectively connected to the push plate 224 and the slider of the arc guide rail 226. The other end of the nozzle mounting frame 225 is used to install the nozzle 205. The nozzle 205 is driven to move by the nozzle adjustment motor 223 to adjust the distance between the nozzle 205 and the polishing wheel 203.

[0036] 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.

[0037] The working principle of the magnetorheological polishing system 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 operating control parameters of the magnetorheological polishing system; next, use the laser tracker 3 and the target ball 301 to measure the pose error of the magnetorheological polishing system in the moving state, compare the measured moving pose with the theoretical pose data to obtain the pose error information, calculate the polishing gap change data through the measured moving pose, and then obtain the change data of the removal function. Finally, adjust the output displacement of the actuator group 227 or adjust the height of the liquid pump 217 or the position of the nozzle 205 to control the change of the removal function, achieve the desired control parameters, and ultimately achieve the purpose of keeping the removal function of each polishing point constant; or calculate the removal function of each polishing trajectory point according to the conversion relationship between the removal function and the polishing gap, and input it as a new processing parameter into the control instruction generation program of the industrial robot 201, so that the change of the removal function of each polishing trajectory point is consistent with the change of the removal function caused by the actual polishing gap change.

[0038] In the second aspect, the present embodiment further provides a magnetorheological polishing method based on actuator adjustment, which is realized by using the above magnetorheological polishing system 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, 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 Z-axis spatial coordinate of the set working point of the polishing wheel into the theoretical Z-axis spatial coordinate of the target ball according to the pose conversion relationship.

[0039] 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 a 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.

[0040] 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.

[0041] The process of measuring the spatial coordinates of the target ball is as follows: when the tool end of the industrial robot is in different postures, the position coordinates of the target ball are measured, and the spatial coordinates of the target ball corresponding to each posture are (x1, y1, z1).

[0042] The process of measuring the spatial coordinates of the target ball is as follows: when the tool end of the industrial robot is in different postures, the position coordinates of the target ball are measured, and the spatial coordinates of the target ball corresponding to each posture are 。

[0043] The process of measuring the spatial coordinates of the working point of the polishing wheel is as follows: the target ball is placed at at least 10 different positions on the outer surface of the polishing wheel and its coordinates are measured, and the center point coordinates of the polishing wheel are obtained through the sphere fitting function of the laser tracker ,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, 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 ,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.

[0044] The tool end of the industrial robot repeats the above measurement process in different postures to obtain the spatial coordinates of the working point of the polishing wheel corresponding to each posture 。

[0045] 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: 。

[0046] 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.

[0047] S2: Under different polishing gaps, by changing the output displacement of the actuator group, fixed-point machining is performed on each machining point of the test polishing element, the volume removal rate of the removal function at each machining point under different polishing gaps is calculated, and data fitting is performed on the discrete volume removal rates of the removal function and the corresponding output displacements of the actuator group under different polishing gaps to obtain the conversion relationship between the polishing gap and the output displacement of the actuator group ;where, Indicates the polishing gap corresponding to the volume removal rate of each removal function Indicates the output displacement of the actuator group Indicates the conversion relationship between the polishing gap and the output displacement of the actuator group

[0048] In the present invention, the change adjustment of the removal function is realized by adjusting the output displacement of the actuator group. The operation for determining the relationship between the output displacement of the actuator group and the change of the removal function is as follows: Use an industrial robot to drive the tool end to perform fixed-point machining for a period of time at different positions on the surface of the test polishing element with different polishing gaps. The output displacements of the actuator group at each machining point are different. Calculate the volume removal rate of the removal function at each machining point under different polishing gaps. Based on the discrete volume removal rates of the removal function and their corresponding output displacements of the actuator group under 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 output displacement of the actuator group. This conversion relationship can be characterized as: 。

[0049] 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

[0050] S3: Use the magnetorheological polishing system to polish the element to be polished. Real-time measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point through a laser tracker, 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

[0051] 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 coordinates and the theoretical Z-axis spatial coordinates of the target ball at each polishing trajectory point , Represents the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point Represents the theoretical Z-axis spatial coordinates 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

[0052] S4: Judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the output displacement of the actuator group at the current polishing trajectory point unchanged; if it exceeds, adjust the output displacement of the actuator group 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

[0053] The adjustment of the removal function variation is achieved by adjusting the output displacement of the actuator group. 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 variation error range, that is , then the trajectory error of the magnetorheological polishing system meets the high-precision machining requirements, and the output displacement of the current actuator group remains unchanged; if , the trajectory error of the magnetorheological polishing system does not meet the high-precision machining requirements. At this time, it is necessary to calculate the polishing gap at the current polishing trajectory point, represents the set initial polishing gap. According to the conversion relationship between the polishing gap at the current polishing trajectory point and the output displacement of the actuator group, as well as the set theoretical removal function volume removal rate, calculate the output displacement of the actuator group and send it to the actuator group through the computer. Finally, regulate the variation of the removal function by adjusting the output displacement of the actuator group to achieve the regulation of the trajectory error of the magnetorheological polishing system.

[0054] Since the variation of the operating pose error of the magnetorheological polishing system is small, the variation can be regarded as the variation of the polishing gap.

[0055] Set the maximum adjustment amount of the output displacement of the actuator group in the computer to be , and the set error range to be , represents the maximum value of the distance error, then: When , keep the output displacement of the actuator group at the current polishing trajectory point unchanged; When and the output displacement of the actuator group at the current polishing trajectory point , adjust the output displacement of the actuator group at the current polishing trajectory point according to the following formula: When and the output displacement of the actuator group at the current polishing trajectory point , adjust the output displacement of the actuator group at the current polishing trajectory point according to the following formula: Among them, represents the set initial output displacement of the actuator group.

[0056] Calculate the time required to regulate the magnetorheological machining module when the actuator group outputs the maximum displacement : ; Among them, represents the output regulation rate of the actuator group; 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 movement time between two adjacent polishing trajectory points when the magnetorheological machining module is at the highest moving speed : : ; Among them, represents the distance between two adjacent polishing trajectory points.

[0057] 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 .

[0058] During the entire machining process, the laser tracker and the target ball are used to continuously measure the pose error of the magnetorheological polishing system, and the running trajectory is adjusted in real time through the magnetorheological polishing system to achieve the desired control parameters, ensure the stability of the removal function during the machining process, and finally achieve the high-precision machining goal.

[0059] Compared with the current mainstream real-time control scheme based on force sensors, the present invention measures the real-time change of the pose of the magnetorheological polishing system during the polishing process through a laser tracker, and uses the output displacement adjustment of the actuator group to achieve real-time constant control of the removal function. This method does not require calibration of measuring devices such as force sensors, is not affected by factors such as the weight of the magnetorheological polishing system, the running accuracy of the equipment itself, the running speed, the posture, and other factors, can measure the pose change of the polishing system in real time during the optical polishing process, intuitively reflect the pose error of the polishing system, and has the advantages of low equipment cost and high measurement accuracy.

[0060] In the third aspect, this embodiment also provides a magnetorheological polishing method based on the height adjustment of a liquid pump, which is implemented by using the above-mentioned magnetorheological polishing system 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 polishing wheel working points 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 polishing wheel working points and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinates of the set polishing wheel working points into the theoretical Z-axis spatial coordinates of the target ball.

[0061] 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. With the help of the line fitting function of the laser tracker (this function is the basic function of the laser tracker), 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.

[0062] The process of using the laser tracker to measure the spatial coordinates of the polishing wheel working points 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 polishing wheel working points and the spatial coordinates of the target ball in each pose.

[0063] 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 .

[0064] The process of measuring the spatial coordinates of the polishing wheel working points is: 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: ; where 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 polishing wheel working point can be obtained by solving the following system of equations , the spatial coordinates of the polishing wheel working point is the spatial coordinate 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.

[0065] Repeat the above measurement process for the tool end of the industrial robot in different postures to obtain the spatial coordinates of the working points of the polishing wheel corresponding to each posture. 。

[0066] Calculate the spatial coordinates of the working points of the polishing wheel according to the following formula and the spatial coordinates of the target ball The pose transformation relationship T between them: 。

[0067] After obtaining the pose transformation relationship T, the theoretical Z-axis spatial coordinates of the set working points 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.

[0068] S2: At different polishing gaps, by changing the height of the liquid pump, 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 under different polishing gaps, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding liquid pump heights under different polishing gaps to obtain the conversion relationship between the polishing gap and the liquid pump height ; where represents the polishing gap corresponding to each volume removal rate of the removal function, represents the height of the liquid pump, represents the conversion relationship between the polishing gap and the liquid pump height.

[0069] The present invention realizes the adjustment of the removal function by adjusting the height of the liquid pump. The operation for determining the relationship between the liquid pump speed and the change of the removal function is as follows: Use the industrial robot to drive the tool end to perform fixed-point machining at different positions on the surface of the test polishing element at different polishing gaps for a period of time. The heights of the liquid pumps at each machining point are different. Calculate the volume removal rate of the removal function at each machining point under different polishing gaps. Based on the discrete volume removal rates of the removal function and their corresponding liquid pump heights under 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 liquid pump height. This conversion relationship can be characterized as: 。

[0070] 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.

[0071] Due to the limited amount of discrete data corresponding to different polishing clearances obtained from experiments, the actual polishing clearance measured during the machining process may not be equal to the polishing clearance data value obtained from experiments. The solution is to use the closest data, that is, the rounding principle. For example: The conversion relationship between the material removal rate MRR of the removal function and the polishing wheel position LW corresponding to the polishing clearances of 1 mm and 2 mm is obtained from experiments. However, the polishing clearance during the machining process is 1.6 mm. At this time, the material removal rate MRR of 2 mm is selected to calculate the conversion relationship between the polishing clearance and the liquid pump height.

[0072] S3: Use the magnetorheological polishing system to polish the component to be polished. Real-time measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point through a laser tracker, 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.

[0073] During the polishing of the component 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 coordinates of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinates 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.

[0074] S4: Judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the liquid pump height at the current polishing trajectory point unchanged; if it exceeds, adjust the liquid pump height through a computer-controlled ball screw stepper motor 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.

[0075] Adjust the change of the removal function by adjusting the liquid pump height. During the polishing of the component 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 system meets the high-precision machining requirements, and the current liquid pump height is maintained unchanged; if , the trajectory error of the magnetorheological polishing system does not meet the high-precision machining requirements. At this time, it is necessary to calculate the polishing clearance at the current polishing trajectory point, represents the set initial polishing clearance. According to the conversion relationship between the polishing clearance and the liquid pump height at the current polishing trajectory point Calculate the height of the liquid pump based on the set theoretical removal function volume removal rate, send it to the drive motor via the computer, and finally adjust the change of the removal function by regulating the height of the liquid pump to achieve the regulation of the trajectory error of the magnetorheological polishing system.

[0076] Since the change amount of the operating pose error of the magnetorheological polishing system is small, the change can be regarded as the change of the polishing gap.

[0077] Set the maximum adjustment amount of the liquid pump height in the computer to be , and set the error range to be , represents the maximum value of the distance error, then: When , keep the height of the liquid pump at the current polishing trajectory point unchanged; When and the height of the liquid pump at the current polishing trajectory point , adjust the height of the liquid pump at the current polishing trajectory point according to the following formula: ; When and the height of the liquid pump at the current polishing trajectory point , adjust the height of the liquid pump at the current polishing trajectory point according to the following formula: ; Among them, represents the set initial height of the liquid pump.

[0078] Calculate the time max required to regulate the magnetorheological processing module when the adjustment amount of the liquid pump height is the maximum value |∆SP |: ; Among them, is the highest adjustment rate of the liquid pump height.

[0079] 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 movement time between two adjacent polishing trajectory points of the magnetorheological processing module at the highest moving speed : ; Among them, represents the distance between two adjacent polishing trajectory points.

[0080] 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 at each polishing track point .

[0081] During the entire machining process, a laser tracker and a target ball are used to continuously measure the pose error of the magnetorheological polishing system, and the running trajectory is adjusted in real time through the magnetorheological polishing system to achieve the desired control parameters, ensure the stability of the removal function during machining, and ultimately achieve the high-precision machining goal.

[0082] 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 system during polishing through a laser tracker, and uses the height adjustment of the liquid pump to achieve real-time constant control of the removal function. This method does not require calibration of measuring devices such as force sensors, is not affected by factors such as the weight of the magnetorheological polishing system, the running accuracy of the equipment itself, the running speed, the posture, and other factors, can measure the pose changes of the polishing system in real time during optical polishing, intuitively reflect the pose error of the polishing system, and has the advantages of low equipment cost and high measurement accuracy.

[0083] In a fourth aspect, this embodiment also provides a magnetorheological polishing method based on nozzle position adjustment, which is implemented by using the above-mentioned magnetorheological polishing system sensed by a laser tracker, 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 polishing wheel working point 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 polishing wheel working point and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinate of the set polishing wheel working point into the theoretical Z-axis spatial coordinate of the target ball.

[0084] 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.

[0085] The process of using the 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: 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 by using the industrial robot. Measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball in each posture by using a laser tracker.

[0086] The process of measuring the spatial coordinates of the target ball is as follows: When the tool end of the industrial robot is in different postures, measure the position coordinates of the target ball, and the spatial coordinates of the corresponding target ball measured in each posture are .

[0087] 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 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, 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: ; wherein, R is the radius of the polishing wheel.

[0088] When the tool end of the industrial robot is in different postures, repeat the above measurement process to obtain the spatial coordinates of the working point of the polishing wheel corresponding to each posture .

[0089] 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: .

[0090] 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.

[0091] S2: At different polishing gaps, by changing the nozzle position, 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 nozzle positions at different polishing gaps to obtain the conversion relationship between the polishing gap and the nozzle position ; wherein, Represents the polishing gap corresponding to the volume removal rate of each removal function. Represents the nozzle position. Represents the conversion relationship between the polishing gap and the nozzle position.

[0092] In the present invention, the change of the removal function is adjusted by adjusting the nozzle position. The operation for determining the relationship between the nozzle position and the change of the removal function is as follows: The industrial robot is used to drive the tool end to perform fixed-point machining for a period of time at different positions on the surface of the test polishing element with different polishing gaps. The nozzle positions of each machining point are different. Calculate the volume removal rate of the removal function at each machining point under different polishing gaps. Based on the discrete volume removal rates of the removal function and their corresponding nozzle positions under 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 nozzle position. This conversion relationship can be characterized as: .

[0093] The different polishing gaps refer to the situation where 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.

[0094] Since the amount of discrete data corresponding to different polishing gaps obtained from the experiment is limited, the actual polishing gap measured during the machining process 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 relationship between the volume removal rate MRR of the removal function and the polishing wheel position LW corresponding to the polishing gaps of 1 mm and 2 mm is obtained from the experiment. However, the polishing gap during the machining process is 1.6 mm. At this time, the volume removal rate MRR of 2 mm is selected to calculate the conversion relationship between the polishing gap and the nozzle position.

[0095] S3: Use the magnetorheological polishing system to polish the element to be polished. Real-time measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point through a laser tracker, 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.

[0096] During the polishing of 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 coordinates of the target ball at each polishing trajectory point. Represents the theoretical Z-axis spatial coordinates 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.

[0097] S4: Determine whether the distance error of each polishing trajectory point exceeds the set error range; if not, keep the nozzle position of the current polishing trajectory point unchanged; if it exceeds, adjust the nozzle position by controlling the nozzle adjustment motor through the computer, change the removal function of the current polishing trajectory point, and finally maintain the constancy of the removal function of each polishing trajectory point.

[0098] Adjust the change of the removal function by adjusting the nozzle position. 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 system meets the high-precision machining requirements, and the current nozzle position remains unchanged; if , the trajectory error of the magnetorheological polishing system does not meet the high-precision machining requirements. At this time, it is necessary to calculate the polishing gap of the current polishing trajectory point, represents the set initial polishing gap. According to the conversion relationship between the polishing gap and the nozzle position of the current polishing trajectory point and the set theoretical removal function volume removal rate, calculate the nozzle position and send it to the nozzle adjustment motor through the computer. Finally, adjust the change of the removal function by adjusting the nozzle position to achieve the control of the trajectory error of the magnetorheological polishing system.

[0099] Since the change amount of the operating pose error of the magnetorheological polishing system is small, the change of <x can be regarded as the change of the polishing gap.

[0100] Set the maximum adjustment amount of the nozzle position in the computer as , and set the error range as , represents the maximum value of the distance error, then: When , keep the nozzle position of the current polishing trajectory point unchanged; When and the nozzle position of the current polishing trajectory point is adjusted according to the following formula: ; When and the nozzle position of the current polishing trajectory point is adjusted according to the following formula: ; Among them, Indicates the set initial position of the nozzle.

[0101] Calculate the adjustment amount at the nozzle position to the maximum value |∆NL max |, and the time required to control the magnetorheological machining module : ; Wherein, is the highest adjustment rate of the nozzle position.

[0102] Count 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 movement time between two adjacent polishing trajectory points of the magnetorheological machining module at the highest moving speed : : ; Wherein, represents the distance between two adjacent polishing trajectory points.

[0103] 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 .

[0104] During the entire machining process, the laser tracker and the target ball are used to continuously measure the pose error of the magnetorheological polishing system, and the running trajectory is adjusted in real time through the magnetorheological polishing system to achieve the desired control parameters, ensure the stability of the removal function during the machining process, and finally achieve the high-precision machining goal.

[0105] Compared with the current mainstream real-time control scheme based on force sensors, the present invention measures the real-time change of the pose of the magnetorheological polishing system during the polishing process through a laser tracker, and uses the adjustment of the nozzle position 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 the weight of the magnetorheological polishing system, the running accuracy of the equipment itself, the running speed, the posture, and other factors, can measure the pose change of the polishing system in real time during the optical polishing process, intuitively reflect the pose error of the polishing system, and has the advantages of low equipment cost and high measurement accuracy.

[0106] In a fifth aspect, this embodiment also provides a magnetorheological polishing method based on removal function adjustment, which is realized by using the above-mentioned magnetorheological polishing system 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 polishing wheel working points 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 polishing wheel working points and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinate of the set polishing wheel working point into the theoretical Z-axis spatial coordinate of the target ball.

[0107] 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.

[0108] The process of using the laser tracker to measure the spatial coordinates of the polishing wheel working points 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 polishing wheel working points and the spatial coordinates of the target ball in each pose.

[0109] 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 .

[0110] The process of measuring the spatial coordinates of the polishing wheel working points is: 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: ; where 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 polishing wheel working point can be obtained by solving the following system of equations , the spatial coordinates of the polishing wheel working point is the spatial coordinate 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.

[0111] Repeat the above measurement process for the tool end of the industrial robot in different postures to obtain the spatial coordinates of the working points of the polishing wheel corresponding to each posture. 。

[0112] Calculate the spatial coordinates of the working points of the polishing wheel according to the following formula and the spatial coordinates of the target ball to obtain the pose transformation relationship T therebetween: 。

[0113] After obtaining the pose transformation relationship T, the theoretical Z-axis spatial coordinates of the set working points 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.

[0114] S2: Perform fixed-point machining on each machining point of the test polishing element at different polishing gaps, 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 the corresponding removal functions at different polishing gaps to obtain the conversion relationship between the polishing gap and the removal function ; where represents the polishing gap corresponding to each volume removal rate of the removal function, represents the removal function, represents the conversion relationship between the polishing gap and the removal function.

[0115] In the present invention, the change of the corresponding removal function during the machining process is calculated through the change information of the polishing gap, and the variable removal function set is used as the input for the next machining during the next machining to realize the deterministic machining of the removal function. Since the pose error of the magnetorheological polishing system is a small quantity, the pose error ±∆d i can be regarded as the change of the polishing gap of the magnetorheological polishing system. In order to compensate for the change of the removal function caused by the polishing gap trajectory error, it is necessary to determine the relationship between the polishing gap and the change of the removal function. The operation is as follows: Perform fixed-point machining for a period of time at different positions on the surface of the test polishing element at different polishing gaps, calculate the volume removal rate of the removal function at each machining point, and based on the discrete volume removal rates of the removal function and the corresponding polishing gap data, 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 removal function, and this conversion relationship can be characterized as: 。

[0116] It is used as the input for the next machining during the next machining to realize the deterministic machining of the removal function. Since the pose error of the magnetorheological polishing system is a small quantity, the pose error ±∆d According to the conversion relationship between the polishing gap and the removal function, calculate the polishing gap at each machining point during the machining process corresponding to the removal function , to obtain the variable removal function set , and use the variable removal function set As new processing parameters Input into the industrial robot control instruction generation program, so that the change of the removal function at each polishing trajectory point is consistent with the removal function caused by the actual polishing gap change, ensuring the certainty of the removal function change in the actual processing process and achieving the high-precision processing goal.

[0117] S3: Use the magnetorheological polishing system to polish the element to be polished. Measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point in real time through a laser tracker, 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 ; Among them, the distance error , represents the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinates of the target ball at each polishing trajectory point.

[0118] 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 coordinates and the theoretical Z-axis spatial coordinates 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.

[0119] S4: Set the error range in the computer to be , represents the maximum value of the distance error, and judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, calculate the removal function corresponding to the polishing trajectory point according to ; if it exceeds, set the distance error , and calculate the removal function corresponding to the polishing trajectory point according to ; Input the removal function corresponding to each polishing trajectory point as new processing parameters into the industrial robot control instruction generation program, so that the change of the removal function at each polishing trajectory point is consistent with the removal function caused by the actual polishing gap change. ; Input the removal function corresponding to each polishing trajectory point

[0120] 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 movement time between two adjacent polishing trajectory points under the highest moving speed of the magnetorheological processing module: ; Among them, represents the distance between two adjacent polishing trajectory points.

[0121] 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 .

[0122] During the entire machining process, a laser tracker and a target ball are used to continuously measure the pose error of the magnetorheological polishing system. After machining is completed, the change in the polishing gap is solved using the measured pose error information, and the corresponding change in the removal function is calculated. When machining next time, a set of variable removal functions is used as the input of the machining parameters, and deterministic machining of the removal function is realized without compensating for the running pose error of the magnetorheological polishing system, and finally, a high-precision machining target is achieved.

[0123] Compared with the current mainstream real-time control scheme based on force sensors, the present invention measures the real-time change in the pose of the magnetorheological polishing system during the polishing process through a laser tracker, and realizes real-time constant control of the removal function by adjusting the output displacement of the actuator group. This method does not require calibration of measuring devices such as force sensors, is not affected by factors such as the weight of the magnetorheological polishing system, the running accuracy of the equipment itself, the running speed, the pose, and other factors. During the optical polishing process, the change in the pose of the polishing system can be measured in real time, intuitively reflecting the pose error of the polishing system, and having the advantages of low equipment cost and high measurement accuracy.

[0124] It should be understood that various forms of the flow shown above can be used, reordering, adding, or deleting steps. 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 limitation is made herein.

[0125] The above specific implementation manners do not constitute a limitation on 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 system based on laser tracker sensing, characterized in that, Including: 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, an actuator group and a supply device. One end of the actuator group is connected to the magnetorheological mounting frame, and the other end of the actuator group is connected to the tool end of the industrial robot. The polishing wheel and the magnet are respectively mounted on the magnetorheological mounting frame. The nozzle is mounted on the magnetorheological mounting frame through a nozzle adjusting seat. The nozzle adjusting seat is used to adjust the position of 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 supply device is arranged on one side of the polishing platform and is used to pump magnetorheological fluid into the nozzle; 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 Z-axis spatial coordinates of the set working point of the polishing wheel into the theoretical Z-axis spatial coordinates of the target ball; A computer, which is used to 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. The computer is also used to, when the distance error exceeds the set error range, adjust the output displacement of the actuator group according to the conversion relationship between the output displacement of the actuator group and the polishing gap, or adjust the height of the supply device according to the conversion relationship between the height of the liquid pump and the polishing gap, or adjust the position of the nozzle according to the conversion relationship between the position of the nozzle and the polishing gap, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point; Alternatively, the computer is used to calculate the removal function at each polishing trajectory point according to the conversion relationship between the removal function and the polishing gap, and input it as a new processing parameter into the industrial robot control instruction generation program, so that the change of the removal function at each polishing trajectory point is consistent with the removal function caused by the actual change of the polishing gap.

2. The magnetorheological polishing system based on laser tracker sensing according to claim 1, wherein The supply device includes a liquid pump, a mounting bracket, a mounting plate, a linear guide rail and a ball screw stepping motor. Among them, the linear guide rail and the ball screw stepping motor are respectively vertically mounted on the mounting bracket, and the linear guide rails are distributed on both sides of the ball screw stepping motor. The liquid pump is mounted on the mounting plate, and the mounting plate is respectively connected to the slider of the linear guide rail and the nut of the ball screw stepping motor.

3. The magnetorheological polishing system based on laser tracker sensing according to claim 1, characterized in that, The nozzle is mounted on the magnetorheological mounting frame through a nozzle adjusting seat, and the position of the nozzle relative to the polishing wheel is adjusted through the nozzle adjusting seat. The nozzle adjusting seat includes a fixed frame, a nozzle adjusting motor, a push plate, a nozzle mounting frame and an arc guide rail. Among them, the fixed frame is mounted on the magnetorheological mounting frame, the nozzle adjusting motor and the arc guide rail are respectively mounted on the fixed frame, the push plate is mounted on the output end of the nozzle adjusting motor, the nozzle mounting frame is respectively connected to the push plate and the slider of the arc guide rail, and the nozzle is mounted on the nozzle mounting frame.

4. The magnetorheological polishing system based on laser tracker sensing according to claim 1, wherein The magnetorheological polishing module further includes a polishing wheel driving device, which 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, and a bearing is installed in the bearing seat. The bearing is connected to the polishing wheel. The driven wheel is sleeved on the bearing, and 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.

5. A magnetorheological polishing method based on actuator adjustment, which is realized by using the magnetorheological polishing system based on laser tracker sensing described in any one of claims 1-4, 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 polishing wheel working point and the spatial coordinates of the target ball when the industrial robot is in different postures, and calculate the pose transformation relationship between the spatial coordinates of the polishing wheel working point and the spatial coordinates of the target ball. According to the pose transformation relationship, convert the theoretical Z-axis spatial coordinates of the set polishing wheel working point into the theoretical Z-axis spatial coordinates of the target ball; S2: At different polishing clearances, by changing the output displacement of the actuator group, perform point-by-point machining on each machining point of the test polishing element, calculate the volume removal rate of the removal function at each machining point under different polishing clearances, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding output displacements of the actuator group under different polishing clearances to obtain the conversion relationship between the polishing clearance and the output displacement of the actuator group ; where represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the output displacement of the actuator group, represents the conversion relationship between the polishing clearance and the output displacement of the actuator group; S3: Use the magnetorheological polishing system to polish the element to be polished. Real-time measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point through the laser tracker, and calculate the distance error between the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point and the theoretical Z-axis spatial coordinates; S4: Judge whether the distance error of each polishing trajectory point exceeds the set error range; if not, keep the output displacement of the actuator group at the current polishing trajectory point unchanged; if it exceeds, adjust the output displacement of the actuator group through the computer, change the removal function at the current polishing trajectory point, and finally maintain the removal function of each polishing trajectory point constant.

6. The magnetorheological polishing method based on actuator adjustment according to claim 5, 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; The maximum adjustment amount of the output displacement of the actuator group is set in the computer to be , and the set error range is , represents the maximum value of the distance error, then: When the output displacement of the actuator group at the current polishing trajectory point remains unchanged; When and the output displacement of the actuator group at the current polishing trajectory point then, the output displacement of the actuator group at the current polishing trajectory point is adjusted according to the following formula: ； When and the output displacement of the actuator group at the current polishing trajectory point then, the output displacement of the actuator group at the current polishing trajectory point is adjusted according to the following formula: ； Among them, represents the initial output displacement of the set actuator group.

7. The magnetorheological polishing method based on actuator adjustment according to claim 5, characterized in that 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.

8. The magnetorheological polishing method based on actuator adjustment according to claim 5, wherein The process of using the 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 the 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 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.

9. A magnetorheological polishing method based on the height adjustment of a liquid pump, which is realized by using the magnetorheological polishing system based on laser tracker sensing described in claim 2, 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 polishing wheel working point and the spatial coordinates of the target ball when the industrial robot is in different postures, and calculate the pose transformation relationship between the spatial coordinates of the polishing wheel working point and the spatial coordinates of the target ball. According to the pose transformation relationship, convert the theoretical Z-axis spatial coordinates of the set polishing wheel working point into the theoretical Z-axis spatial coordinates of the target ball; S2: At different polishing clearances, by changing the height of the liquid pump, 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 liquid pump heights at different polishing clearances to obtain the conversion relationship between the polishing clearance and the liquid pump height ; where represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the height of the liquid pump, represents the conversion relationship between the polishing clearance and the liquid pump height; S3: Use the magnetorheological polishing system to polish the element to be polished. Measure the actual Z-axis 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 Z-axis spatial coordinates and the theoretical Z-axis 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 height of the liquid pump at the current polishing trajectory point unchanged. If it exceeds, adjust the height of the liquid pump by controlling the ball screw stepper motor 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.

10. The magnetorheological polishing method based on the height adjustment of a liquid pump according to claim 9, 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; The maximum adjustable amount of the height of the liquid pump set in the computer is , and the set error range is , represents the maximum value of the distance error, then: When the liquid pump height at the current polishing trajectory point remains unchanged; When and the liquid pump height of the current polishing trajectory point at this time, adjust the liquid pump height of the current polishing trajectory point according to the following formula as follows: ； When and the liquid pump height of the current polishing trajectory point at this time, adjust the liquid pump height of the current polishing trajectory point according to the following formula as follows: ； Among them, represents the set initial height of the liquid pump.

11. The magnetorheological polishing method based on the height adjustment of a liquid pump according to claim 9, characterized in that, 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 measurement 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.

12. The magnetorheological polishing method based on the height adjustment of the liquid pump according to claim 9, wherein 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 process of measuring 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 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. 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 : ； Among them, R represents the radius of the polishing wheel.

13. A magnetorheological polishing method based on nozzle position adjustment, which is realized by using the magnetorheological polishing system based on laser tracker perception described in claim 3, 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 polishing wheel working point and the target ball when the industrial robot is in different postures, and calculate the pose conversion relationship between the spatial coordinates of the polishing wheel working point and the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinates of the set polishing wheel working point into the theoretical Z-axis spatial coordinates of the target ball. S2: At different polishing gaps, by changing the nozzle position, 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 under different polishing gaps, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding nozzle positions under different polishing gaps to obtain the conversion relationship between the polishing gap and the nozzle position ; among them, represents the polishing gap corresponding to each volume removal rate of the removal function, represents the nozzle position, represents the conversion relationship between the polishing gap and the nozzle position; S3: Use the magnetorheological polishing system to polish the element to be polished. Measure the actual Z-axis 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 Z-axis spatial coordinates and the theoretical Z-axis 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 nozzle position at the current polishing trajectory point unchanged. If it exceeds, adjust the nozzle position by controlling the nozzle adjustment motor 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.

14. The magnetorheological polishing method based on nozzle position adjustment according to claim 13, 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; The maximum adjustment amount of the nozzle position set in the computer is , and the set error range is , represents the maximum value of the distance error, then: When the nozzle position of the current polishing trajectory point remains unchanged; When and the nozzle position of the current polishing trajectory point at this time, adjust the nozzle position of the current polishing trajectory point according to the following formula as follows: ； When and the nozzle position of the current polishing trajectory point then, according to the following formula, adjust the nozzle position of the current polishing trajectory point as follows: ； Among them, represents the set initial position of the nozzle.

15. The magnetorheological polishing method based on nozzle position adjustment according to claim 13, wherein The process of establishing the measurement coordinate system of the laser tracker is as follows: Use a 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 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.

16. The magnetorheological polishing method based on nozzle position adjustment according to claim 13, characterized in that, 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. The center point coordinates of the polishing wheel can be obtained 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; 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 : ； Among them, R represents the radius of the polishing wheel.

17. A magnetorheological finishing method based on removal function adjustment, which is realized by using the magnetorheological finishing system based on laser tracker perception described in any one of claims 1-4, 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 polishing wheel working point 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 polishing wheel working point and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical Z-axis spatial coordinate of the set polishing wheel working point into the theoretical Z-axis spatial coordinate of the target ball; S2: Perform fixed-point machining on each machining point of the test polishing element at different polishing clearances, calculate the volume removal rate of the removal function at each machining point under different polishing clearances, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding removal functions under different polishing clearances to obtain the conversion relationship between the polishing clearance and the removal function ; where represents the polishing clearance corresponding to the volume removal rate of each removal function, represents the removal function, represents the conversion relationship between the polishing clearance and the removal function; S3: Use the magnetorheological polishing system to polish the element to be polished. Real-time measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point through a laser tracker, 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 ; Among them, the distance error , represents the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinates of the target ball at each polishing trajectory point; S4: Set the error range in the computer to , Indicates the maximum value of the distance error, and judges whether the distance error of each polishing track point exceeds the set error range; if not, according to Calculate the removal function corresponding to the polishing trajectory point If exceeded, the distance error ,according to Removal function corresponding to polishing trajectory points ; The removal function corresponding to each polishing trajectory point The new processing parameters are input into the industrial robot control instruction generation program so that the change of the removal function of each polishing trajectory point is consistent with the removal function caused by the actual polishing gap change.

18. The magnetorheological polishing method based on removal function adjustment according to claim 17, wherein The process of establishing the measurement coordinate system of the laser tracker is as follows: Use a 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 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.

19. The magnetorheological polishing method based on removal function adjustment according to claim 17, wherein, 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 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 using 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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