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

Abstract

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

Description

Technical Field

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

[0002] Magnetorheological Finishing (MRF) is an advanced optical manufacturing technology developed in recent years. It has many advantages such as a stable removal function, controllable edge effect, small subsurface damage layer, no replication effect, strong shape correction ability, and high processing accuracy. Therefore, magnetorheological polishing technology has received extensive attention in high-precision optical processing. The existing magnetorheological polishing machining centers mainly integrate magnetorheological polishing modules on numerical control machine tools. However, some deficiencies of numerical control machine tools (such as low degrees of freedom, large floor area, high cost, etc.) limit the deviation of aspherical surfaces and it is difficult to perform precise pose control along the surface normal. In view of these deficiencies of numerical control machine tools, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. Six-degree-of-freedom industrial robots have the advantages of high degrees of freedom, small floor area, large processing range, low cost, etc., which make up for the deficiencies of numerical control machine tools. Therefore, when integrating magnetorheological polishing modules on industrial robots, it is theoretically possible to achieve high-precision processing of large-aperture complex surface optical elements. 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 processing. At the same time, 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 processing, a decrease in the certainty of the removal function, and affects the final processing 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] Regarding the problem of low motion accuracy of industrial robots, the current real-time control scheme based on constant-force grinding and polishing has become a research hotspot, and the force-position control method has become a common method for controlling the constant-force grinding and polishing of robots. A common application method is to place a force sensor between the processing tool and the industrial robot. First, the gravity calibration of the force sensor is carried out to ensure the accurate determination of the measurement. The pose error is calculated by measuring the change of the force, and then the pose error of the industrial robot is compensated by means of the industrial robot body or other motion compensation mechanisms to achieve constant-force control. The high-efficiency processing of large-aperture optical elements relies on the magnetorheological processing equipment of large-size polishing wheels, and the weight of the magnetorheological processing module of large-size polishing wheels is generally more than one hundred kilograms. However, for a magnetorheological processing module weighing hundreds of kilograms, the force change caused by the pose error of the industrial robot is only dozens of Newtons. When high-precision processing is required, the force needs to be constant at several Newtons or even a fraction of a Newton. This requires the absolute measurement accuracy of measurement equipment such as force sensors to reach one ten-thousandth, and the force sensor also needs to be in a state of variable speed and variable pose movement. Force sensors that meet these requirements are often extremely expensive, greatly increasing the cost of the equipment. Summary of the Invention

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

[0005] To achieve the above purpose, the technical solution of the present invention is realized as follows: A magnetorheological polishing device based on the perception of a laser tracker includes: A polishing platform, on which a component to be polished and a test polishing component 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 component is located or the position where the component to be polished is located; the magnetorheological polishing module is used to polish the component to be polished or the test polishing component. The magnetorheological polishing module includes a magnetorheological mounting frame, a polishing wheel, a nozzle, a magnet, and a liquid pump. The magnetorheological mounting frame is installed at the tool end of the industrial robot. The nozzle, the polishing wheel, and the magnet are respectively installed on the magnetorheological mounting frame. The liquid pump is arranged on the industrial robot. The liquid pump is used to pump magnetorheological fluid into the nozzle, and the nozzle is used to spray the magnetorheological fluid onto the polishing wheel. The magnet is used to change the stiffness of the magnetorheological fluid, and the polishing wheel is used to polish the test polishing component or the component to be polished; A laser tracker, the target ball of which is installed at 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 poses, 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 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 adjust the rotational speed of the liquid pump according to the conversion relationship between the rotational speed of the liquid pump and the polishing gap or adjust the rotational speed of the polishing wheel according to the conversion relationship between the rotational speed of the polishing wheel and the polishing gap when the distance error exceeds the set error range, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point.

[0006] Further, the magnetorheological polishing module further includes a polishing wheel driving device. The polishing wheel driving device includes a driving motor, a driving wheel, a driven wheel and a synchronous belt. The driving motor is installed on the magnetorheological mounting frame. A bearing seat is installed on the magnetorheological mounting frame. A bearing is installed in the bearing seat. The bearing is connected to the polishing wheel. The driven wheel is sleeved on the bearing. The driving wheel is sleeved on the output end of the driving motor. The synchronous belt is tensioned between the driven wheel and the driving wheel.

[0007] A magnetorheological polishing method based on the adjustment of the rotational speed of the liquid pump, which is realized by using the above-mentioned magnetorheological polishing equipment based on the laser tracker perception, 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; S2: At different polishing gaps, by changing the rotational speed 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 gaps, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding liquid pump speeds at different polishing gaps to obtain the conversion relationship between the polishing gap and the liquid pump speed ; where represents the polishing gap corresponding to each volume removal rate of the removal function, represents the rotational speed of the liquid pump, represents the conversion relationship between the polishing gap and the rotational speed of the liquid pump; S3: Use the magnetorheological polishing equipment to polish the element to be polished. Measure the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point in real time 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; S4: Judge whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the rotational speed of the liquid pump at the current polishing trajectory point unchanged; if it exceeds, adjust the rotational speed of the liquid pump through the computer 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.

[0008] Further, the distance error , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, and represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point; The maximum adjustment amount of the liquid pump speed is set to in the computer, and the set error range is . Let represent the maximum value of the distance error, then: When , keep the liquid pump speed at the current polishing trajectory point unchanged; When and the liquid pump speed at the current polishing trajectory point , adjust the liquid pump speed at the current polishing trajectory point according to the following formula: When and the liquid pump speed at the current polishing trajectory point , adjust the liquid pump speed at the current polishing trajectory point according to the following formula: ; wherein, represents the set initial speed of the liquid pump.

[0009] Further, 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.

[0010] Further, 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. 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: ; where a, b, and c are the normal vectors of the straight line, obtained through the teach pendant of the industrial robot; Solve for 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 : ; where R represents the radius of the polishing wheel.

[0011] A magnetorheological polishing method based on the adjustment of the polishing wheel speed, realized by using the above magnetorheological polishing equipment based on laser tracker sensing, includes the following steps: 1]S1: Establish a measurement coordinate system for the laser tracker. Use the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different postures, and calculate the pose conversion relationship between the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball. According to the pose conversion relationship, convert the theoretical 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: At different polishing gaps, by changing the polishing wheel speed, 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 polishing wheel speeds under different polishing gaps to obtain the conversion relationship between the polishing gap and the polishing wheel speed ; where represents the polishing gap corresponding to each volume removal rate of the removal function, represents the polishing wheel speed, represents the conversion relationship between the polishing gap and the polishing wheel speed; S3: Use the magnetorheological polishing equipment 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 of the target ball at each polishing trajectory point and the theoretical Z-axis spatial coordinate; S4: Determine whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the polishing wheel speed at the current polishing trajectory point unchanged; if it exceeds, adjust the polishing wheel speed by computer controlling the drive 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.

[0012] 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 polishing wheel speed in the computer to , and set the error range to , represents the maximum value of the distance error, then: When , keep the polishing wheel speed at the current polishing trajectory point unchanged; When and the polishing wheel speed at the current polishing trajectory point , adjust the polishing wheel speed at the current polishing trajectory point according to the following formula: ; When and the polishing wheel speed at the current polishing trajectory point , adjust the polishing wheel speed at the current polishing trajectory point according to the following formula: ; where represents the set initial speed of the polishing wheel.

[0013] 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.

[0014] 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 working point of the polishing wheel : ; wherein, R represents the radius of the polishing wheel.

[0015] Compared with the prior art, the present invention measures the real-time change of the pose of the magnetorheological polishing equipment during the polishing process through a laser tracker, and realizes the real-time constant control of the removal function by adjusting the polishing wheel speed or the liquid pump speed. This method does not require calibration of measurement devices such as force sensors, and is not affected by the weight of the magnetorheological polishing equipment, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the pose change of the polishing equipment can be measured in real time, and the pose error of the polishing equipment can be intuitively reflected, which has the advantages of low equipment cost and high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. is a schematic structural diagram of the magnetorheological polishing equipment based on laser tracker perception according to an embodiment of the present invention.

[0017] Reference numerals: polishing platform 1, element to be polished 101, test polishing element 102, industrial robot 201, magnetorheological mounting bracket 202, polishing wheel 203, nozzle 205, liquid pump 206, drive motor 207, driving wheel 208, driven wheel 209, synchronous belt 210, laser tracker 3, target ball 301, computer 4. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described with reference to the 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.

[0019] 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 do not constitute a limitation to the present invention.

[0020] In view of the deficiencies of the force-position control method based on force sensors, the present invention proposes a magnetorheological polishing device and polishing method based on laser tracker sensing. By measuring the real-time changes in the pose of the polishing device during the polishing process with a laser tracker, different control methods (polishing wheel speed adjustment / liquid pump speed adjustment) are used to achieve real-time constancy of the removal function. This method does not require calibration of measurement devices such as force sensors and is not affected by factors such as the weight of the magnetorheological processing module, the operating accuracy of the device itself, the operating speed, the posture, and other factors. During the optical polishing process, the pose changes of the polishing device can be measured in real time, intuitively reflecting the pose error of the polishing device, and having the advantage of high measurement accuracy.

[0021] The following uses specific embodiments to elaborate in detail on maintaining the constancy of the removal function.

[0022] In a first aspect, this embodiment provides a magnetorheological polishing device based on laser tracker sensing. The structure of the device is as Figure 1 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 (not shown in the figure), a nozzle 205, a liquid pump 206, and a polishing wheel driving device. The magnetorheological mounting frame 202 is installed at the tool end of the industrial robot 201. The polishing wheel driving device is installed on the magnetorheological mounting frame 202 and is used to drive the polishing wheel 203 to rotate to polish the component to be polished 101 or the test polishing component 102; the nozzle 205 is installed on the magnetorheological mounting frame 202 and is used to spray magnetorheological fluid onto the polishing wheel 203; the magnet is installed on the magnetorheological mounting frame 202 and is used to change the stiffness of the magnetorheological fluid; the liquid pump 206 is installed on the industrial robot 201 and is connected to the nozzle 205 through a pipeline and is used to pump magnetorheological fluid into the nozzle 205. The liquid pump 206 selects the DFLD vertical multistage pump of Shanghai Dongfang Pump Industry Co., Ltd. A laser tracker 3, which is arranged on one side of the polishing platform 1 and is used in cooperation with a target ball 301. The target ball 301 is at the tool end of the industrial robot 201. The laser tracker 3 is used to measure the spatial coordinates of the polishing wheel working point (the polishing wheel working point refers to the lowest point of the polishing wheel when the magnetorheological polishing device 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 polishing wheel working point 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 adjust the rotational speed of the liquid pump according to the conversion relationship between the rotational speed of the liquid pump and the polishing gap or adjust the rotational speed of the polishing wheel according to the conversion relationship between the rotational speed of the polishing wheel and the polishing gap when the distance error exceeds the set error range, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point.

[0023] The polishing wheel driving device includes a driving motor 207, a driving pulley 208, a driven pulley 209 and a synchronous belt 210. The driving motor 207 is installed on the magnetorheological mounting bracket 202. A bearing seat is installed on the magnetorheological mounting bracket 202. A bearing is installed in the bearing seat. The bearing is connected to the polishing wheel 203. The driven pulley 209 is sleeved on the bearing. The driving pulley 208 is sleeved on the output end of the driving motor 207. The synchronous belt 210 is tensioned between the driven pulley 209 and the driving pulley 208. The polishing wheel 203 is driven to rotate by the driving motor 207. Reference can be made to the Chinese patent with the publication date of July 12, 2024 and the publication number of CN118322074A.

[0024] 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.

[0025] The working principle of the magnetorheological polishing equipment based on the perception of the laser tracker is as follows: First, use the laser tracker 3 to calibrate the pose conversion relationship between the target ball 301 and the lowest point of the polishing wheel 203; then set the operation control parameters of the magnetorheological polishing equipment; then use the laser tracker 3 and the target ball 301 to measure the pose error of the magnetorheological polishing equipment in the 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 rotational speed of the polishing wheel 203 or the rotational speed of the liquid pump 206 to control the change of the removal function, achieve the desired control parameters, and ultimately achieve the purpose of keeping the removal function constant at each polishing point.

[0026] In a second aspect, the present embodiment also provides a magnetorheological polishing method based on the adjustment of the rotational speed of the liquid pump, which is implemented by using the above-mentioned magnetorheological polishing equipment based on the perception of the laser tracker, 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.

[0027] 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.

[0028] 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.

[0029] 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. The spatial coordinates of the corresponding target ball measured in each posture are .

[0030] 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. 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.

[0031] Repeat the above measurement process for the tool end of the industrial robot in different poses to obtain the spatial coordinates of the working points of the polishing wheel corresponding to each pose. 。

[0032] 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 is as follows: 。

[0033] 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.

[0034] S2: At different polishing gaps, by changing the liquid pump speed, perform fixed-point machining on each machining point of the test polishing element, calculate the volume removal rate of the removal function for each machining point at different polishing gaps, and perform data fitting on the discrete volume removal rates of the removal function and their corresponding liquid pump speeds at different polishing gaps to obtain the conversion relationship between the polishing gap and the liquid pump speed ; where represents the polishing gap corresponding to each volume removal rate of the removal function, represents the liquid pump speed, represents the conversion relationship between the polishing gap and the liquid pump speed.

[0035] In the present invention, the change of the removal function is adjusted by adjusting the liquid pump speed. 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 for a period of time at different positions on the surface of the test polishing element with different polishing gaps. The liquid pump speeds of each machining point are different. Calculate the volume removal rate of the removal function for each machining point at different polishing gaps. Based on the discrete volume removal rates of the removal function and their corresponding liquid pump speeds at different polishing gaps, use the Polyfit instruction of Matlab (this instruction is a basic general instruction of the Matlab software) to perform data fitting to obtain the conversion relationship between the polishing gap and the liquid pump speed. This conversion relationship can be characterized as: 。

[0036] 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.

[0037] Due to the limited amount of discrete data corresponding to different polishing gaps obtained from experiments, the actual polishing gap measured during the processing may not be equal to the polishing gap data value obtained from experiments. The solution is to adopt 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 liquid pump speed SV corresponding to the polishing gaps of 1 mm and 2 mm is obtained from experiments. However, the polishing gap during the processing 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 gap and the liquid pump speed SV.

[0038] S3: Use the magnetorheological polishing equipment 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.

[0039] Continuously measure the spatial coordinates of the target ball during the polishing of the component 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.

[0040] S4: Determine whether the distance error at each polishing trajectory point exceeds the set error range; if not, keep the liquid pump speed at the current polishing trajectory point unchanged; if it exceeds, adjust the liquid pump speed 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.

[0041] Adjust the change of the removal function by adjusting the liquid pump speed. 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 equipment meets the high-precision processing requirements, and the current liquid pump speed is maintained unchanged; if , the trajectory error of the magnetorheological polishing equipment does not meet the high-precision processing requirements. At this time, it is necessary to calculate the polishing gap , represents the set initial polishing gap. According to the conversion relationship between the polishing gap and the liquid pump speed at the current polishing trajectory point Calculate the rotational speed of the liquid pump based on the set theoretical removal function volume removal rate, and send it to the motor of the liquid pump through the computer. Finally, regulate the change of the removal function by adjusting the rotational speed of the liquid pump to achieve the regulation of the trajectory error of the magnetorheological polishing equipment.

[0042] Since the change amount of the operating pose error of the magnetorheological polishing equipment is small, the change can be regarded as the change of the polishing gap.

[0043] Set the maximum adjustment amount of the rotational speed of the liquid pump in the computer to be ; then: When , keep the rotational speed of the liquid pump at the current polishing trajectory point unchanged; When and the rotational speed of the liquid pump at the current polishing trajectory point , adjust the rotational speed of the liquid pump at the current polishing trajectory point according to the following formula: ; When and the rotational speed of the liquid pump at the current polishing trajectory point , adjust the rotational speed of the liquid pump at the current polishing trajectory point SV i according to the following formula: ; Among them, represents the set initial rotational speed of the liquid pump.

[0044] Calculate the time required to regulate the magnetorheological processing module when the adjustment amount of the rotational speed of the liquid pump is the maximum value : ; Among them, represents the fastest adjustment rate of the rotational speed of the liquid pump; 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.

[0045] When generating the processing 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 trajectory point .

[0046] During the entire machining process, a laser tracker and a target ball are used to continuously measure the pose error of the magnetorheological finishing equipment, and the running trajectory is adjusted in real time through the magnetorheological finishing equipment to achieve the desired control parameters, ensure the stability of the removal function during machining, and finally achieve the high-precision machining goal.

[0047] 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 finishing equipment during polishing through a laser tracker, and realizes the real-time constant control of the removal function by adjusting the rotational speed of the liquid pump. This method does not require calibration of measuring devices such as force sensors, and is not affected by the weight of the magnetorheological finishing equipment, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the pose changes of the polishing equipment can be measured in real time, and the pose error of the polishing equipment can be intuitively reflected, which has the advantages of low equipment cost and high measurement accuracy.

[0048] In a third aspect, the present embodiment further provides a magnetorheological polishing method based on the adjustment of the polishing wheel rotational speed, which is realized by using the above-mentioned magnetorheological finishing equipment 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 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.

[0049] 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.

[0050] 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, drive the polishing wheel to at least 12 different poses 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 using a laser tracker.

[0051] 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 .

[0052] The process of measuring the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates. Obtain the center point coordinates of the polishing wheel through the sphere fitting function of the laser tracker , and the straight line passing through the center point of the polishing wheel is: ; where a, b, and c are the normal vectors of the straight line, obtained through the teach pendant of the industrial robot; Since the straight line passes through the working point of the polishing wheel, the spatial coordinates of the working point of the polishing wheel can be obtained by solving the following system of equations , and the spatial coordinates of the working point of the polishing wheel are the spatial coordinates corresponding to the minimum value of the Z-axis coordinate in the solution of the system of equations: ; where R is the radius of the polishing wheel.

[0053] Repeat the above measurement process when the tool end of the industrial robot is in different postures to obtain the spatial coordinates of the working point of the polishing wheel corresponding to each posture .

[0054] 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: .

[0055] 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.

[0056] S2: At different polishing clearances, by changing the polishing wheel speed, 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 polishing wheel speeds at different polishing clearances to obtain the conversion relationship between the polishing clearance and the polishing wheel speed ; where Denote the polishing gap corresponding to the volume removal rate of each removal function. Denote the polishing wheel rotation speed. Denote the conversion relationship between the polishing gap and the polishing wheel rotation speed.

[0057] In the present invention, the adjustment of the removal function is achieved by adjusting the polishing wheel rotation speed. The operation for determining the relationship between the polishing wheel rotation speed 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 polishing wheel rotation speeds 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 polishing wheel rotation speeds 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 polishing wheel rotation speed. This conversion relationship can be characterized as: .

[0058] The different polishing gaps refer to 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.

[0059] 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 rotation speed V 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, select the volume removal rate MRR of 2 mm to calculate the conversion relationship between the polishing gap and the polishing wheel rotation speed V.

[0060] S3: Use the magnetorheological polishing equipment 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.

[0061] 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 , Denote the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point. Denote the theoretical Z-axis spatial coordinates of the target ball at each polishing trajectory point. Denote the error range of the set distance error. Denote the maximum value of the distance error.

[0062] S4: Determine whether the distance error of each polishing trajectory point exceeds the set error range; if not, keep the polishing wheel speed of the current polishing trajectory point unchanged; if it exceeds, adjust the polishing wheel speed by computer-controlled drive motor to change the removal function of the current polishing trajectory point, and finally maintain the constancy of the removal function of each polishing trajectory point.

[0063] Adjust the change of the removal function by adjusting the polishing wheel speed. During the polishing process of the element to be polished, the laser tracker continuously measures the spatial coordinates of the target ball. If the distance error is within the allowable change error range, that is , then the trajectory error of the magnetorheological polishing equipment meets the high-precision machining requirements, and the current polishing wheel speed is maintained unchanged; if , the trajectory error of the magnetorheological polishing equipment 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 of the current polishing trajectory point and the polishing wheel speed, and the set theoretical removal function volume removal rate, calculate the polishing wheel speed and send it to the drive motor through the computer. Finally, regulate the change of the removal function by adjusting the polishing wheel speed to achieve the regulation of the trajectory error of the magnetorheological polishing equipment.

[0064] Since the change amount of the running pose error of the magnetorheological polishing equipment is small, the change of can be regarded as the change of the polishing gap.

[0065] To ensure processing safety and that the polishing wheel speed does not affect processing, set the maximum adjustment amount of the polishing wheel speed in the computer to , then: When , keep the polishing wheel speed of the current polishing trajectory point unchanged; When and the polishing wheel speed of the current polishing trajectory point, adjust the polishing wheel speed of the current polishing trajectory point according to the following formula: ; When and the polishing wheel speed of the current polishing trajectory point, adjust the polishing wheel speed of the current polishing trajectory point according to the following formula: ; Among them, Represents the initial rotational speed of the set polishing wheel.

[0066] Calculate when the adjustment amount of the polishing wheel rotational speed is the maximum value The time required to control the magnetorheological machining module : ; Among them, Represents the fastest adjustment rate of the polishing wheel rotational speed; 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 ; ; The minimum movement time between adjacent two polishing trajectory points when the magnetorheological machining module is moving at the highest speed Calculate the magnetorheological machining module at the highest moving speed : : ; Among them, Represents the distance between adjacent two polishing trajectory points.

[0067] 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 .

[0068] During the entire machining process, the laser tracker and the target ball are used to continuously measure the pose error of the magnetorheological polishing equipment, and the running trajectory is adjusted in real time through the magnetorheological polishing equipment to achieve the desired control parameters, ensure the stability of the removal function during the machining process, and finally achieve the high-precision machining goal.

[0069] 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 equipment during the polishing process through a laser tracker, and uses the adjustment of the polishing wheel to achieve real-time constant control of the removal function. This method does not require calibration of measurement devices such as force sensors, is not affected by factors such as the weight of the magnetorheological polishing equipment, the running accuracy of the equipment itself, the running speed, the posture, and other factors. During the optical polishing process, the pose change of the polishing equipment can be measured in real time, intuitively reflecting the pose error of the polishing equipment, and having the advantages of low equipment cost and high measurement accuracy.

[0070] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps recited 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 imposed herein.

[0071] The above specific embodiments 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 device based on laser tracker sensing, characterized in that, Including: A polishing platform, on which a component to be polished and a test polishing component 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 component is located or the position where the component to be polished is located. The magnetorheological polishing module is used to polish the component to be polished or the test polishing component. The magnetorheological polishing module includes a magnetorheological mounting frame, a polishing wheel, a nozzle, a magnet, and a liquid pump. The magnetorheological mounting frame is installed at the tool end of the industrial robot. The nozzle, the polishing wheel, and the magnet are respectively installed on the magnetorheological mounting frame. The liquid pump is arranged on the industrial robot or on one side of the industrial robot. The liquid pump is used to pump magnetorheological fluid into the nozzle. The nozzle is used to spray the 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 component or the component to be polished; A laser tracker, whose target ball is installed at the tool end of the industrial robot. The laser tracker is used 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 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; 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 adjust the rotational speed of the liquid pump according to the conversion relationship between the rotational speed of the liquid pump and the polishing gap or adjust the rotational speed of the polishing wheel according to the conversion relationship between the rotational speed of the polishing wheel and the polishing gap when the distance error exceeds the set error range, so as to adjust the removal function and maintain the constancy of the removal function at each polishing trajectory point.

2. The magnetorheological polishing device based on laser tracker sensing according to claim 1, wherein, The magnetorheological polishing module further includes a polishing wheel driving device. The polishing wheel driving device includes a driving motor, a driving wheel, a driven wheel, and a synchronous belt. The driving motor is installed on the magnetorheological mounting frame. A bearing seat is installed on the magnetorheological mounting frame. A bearing is installed in the bearing seat. The bearing is connected to the polishing wheel. The driven wheel is sleeved on the bearing. The driving wheel is sleeved on the output end of the driving motor. The synchronous belt is tensioned between the driven wheel and the driving wheel.

3. A magnetorheological polishing method based on the rotational speed adjustment of a liquid pump, which is realized by using the magnetorheological polishing equipment based on laser tracker sensing described in claim 1 or 2, and is characterized in that Including the following steps: S1: Establish a measurement coordinate system of the laser tracker, use the laser tracker to measure the spatial coordinates of the polishing wheel working point 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 polishing wheel working point and the spatial coordinates of the target ball, and 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 according to the pose conversion relationship; S2: At different polishing clearances, by changing the rotational speed 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 rotational speeds under different polishing clearances to obtain the conversion relationship between the polishing clearance and the liquid pump rotational speed. ; Among them, represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the rotational speed of the liquid pump, represents the conversion relationship between the polishing clearance and the liquid pump rotational speed; S3: Use the magnetorheological polishing equipment to polish the component to be polished, and use the laser tracker to measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point in real time, 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 rotational speed of the liquid pump at the current polishing trajectory point unchanged; if it exceeds, adjust the rotational speed of the liquid pump 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.

4. The magnetorheological polishing method based on the rotational speed adjustment of the liquid pump according to claim 3, wherein Distance error , represents the actual Z-axis spatial coordinate of the target ball at each polishing trajectory point, represents the theoretical Z-axis spatial coordinate of the target ball at each polishing trajectory point; Set the maximum adjustment amount of the liquid pump speed in the computer to be , and set the error range to be , represents the maximum value of the distance error, then: When the liquid pump speed at the current polishing trajectory point remains unchanged; When and the liquid pump speed at the current polishing trajectory point then, adjust the liquid pump speed at the current polishing trajectory point according to the following formula as follows: ； When and the liquid pump speed at the current polishing trajectory point then, the liquid pump speed at the current polishing trajectory point is adjusted according to the following formula as follows: ； Among them, represents the set initial rotational speed of the liquid pump.

5. The magnetorheological polishing method based on the rotational speed adjustment of the liquid pump according to claim 3, wherein The process of establishing the measurement coordinate system of the laser tracker is as follows: Use the laser tracker to measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system respectively. The number of measured points on each axis is not less than 10. Use the line fitting function of the laser tracker to perform linear fitting on the measured points on each axis, and use the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

6. The magnetorheological polishing method based on the rotational speed adjustment of the liquid pump according to claim 3, wherein, The process of using the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different 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 working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in each pose; The measurement process of the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates, and obtain the coordinates of the center point of the polishing wheel through the ball fitting function of the laser tracker. , and the straight line passing through the center point of the polishing wheel is: ； Where a, b, and c are the normal vectors of the straight line, obtained through the teach pendant of the industrial robot; 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 : ； Where R represents the radius of the polishing wheel.

7. A magnetorheological polishing method based on the adjustment of the polishing wheel rotation speed, which is realized by using the magnetorheological polishing equipment based on the perception of a laser tracker 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 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 coordinates of the set working point of the polishing wheel into the theoretical Z-axis spatial coordinates of the target ball according to the pose conversion relationship; S2: At different polishing clearances, by changing the polishing wheel speed, 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 polishing wheel speeds under different polishing clearances to obtain the conversion relationship between the polishing clearance and the polishing wheel speed. ; Among them, represents the polishing clearance corresponding to each volume removal rate of the removal function, represents the polishing wheel speed, represents the conversion relationship between the polishing clearance and the polishing wheel speed; S3: Use the magnetorheological polishing equipment to polish the element to be polished, and use the laser tracker to measure the actual Z-axis spatial coordinates of the target ball at each polishing trajectory point in real time, 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 polishing wheel speed at the current polishing trajectory point unchanged; if it exceeds, adjust the polishing wheel speed by controlling the drive 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.

8. The magnetorheological polishing method based on the polishing wheel rotation speed adjustment according to claim 7, 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 polishing wheel rotation speed set in the computer is , and the set error range is , represents the maximum value of the distance error, then: When the polishing wheel speed of the current polishing trajectory point remains unchanged; When and the polishing wheel speed of the current polishing trajectory point at this time, adjust the polishing wheel speed of the current polishing trajectory point according to the following formula as follows: ； When and the polishing wheel speed at the current polishing trajectory point then, adjust the polishing wheel speed at the current polishing trajectory point according to the following formula as follows: ； Among them, represents the initially set rotational speed of the polishing wheel.

9. The magnetorheological polishing method based on the polishing wheel speed adjustment according to claim 7, wherein The process of establishing the measurement coordinate system of the laser tracker is as follows: Use the laser tracker to measure the coordinates of points on each axis when the industrial robot moves along the X-axis and Y-axis of the tool coordinate system respectively. The number of measured points on each axis is not less than 10. Use the line fitting function of the laser tracker to perform linear fitting on the measured points on each axis, and use the fitted line as the measurement coordinate system of the laser tracker, that is, the measurement coordinate system of the laser tracker is parallel to the tool coordinate system of the industrial robot.

10. The magnetorheological polishing method based on the adjustment of the polishing wheel rotation speed according to claim 7, wherein, The process of using the laser tracker to measure the spatial coordinates of the working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in different 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 working point of the polishing wheel and the spatial coordinates of the target ball when the industrial robot is in each pose; The measurement process of the spatial coordinates of the working point of the polishing wheel is as follows: Place the target ball at at least 10 different positions on the outer surface of the polishing wheel and measure its coordinates. 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 taking them as the spatial coordinates of the working point of the polishing wheel : ； Among them, R represents the radius of the polishing wheel.

Images