Magnetorheological polishing equipment based on electromagnetic flowmeter sensing and polishing method thereof

Abstract

The invention relates to the technical field of magneto-rheological polishing, in particular to magneto-rheological polishing equipment based on sensing of an electromagnetic flowmeter and a polishing method of the magneto-rheological polishing equipment based on sensing of the electromagnetic flowmeter. Coarse-fine two-stage adjustment of magnetorheological fluid flow fluctuation is achieved by controlling the rotating speed of a liquid pump and controlling the position of a magnet or the position of a polishing wheel, so that the magnetorheological fluid flow fluctuation of each polishing point meets the high-precision polishing requirement, and it is guaranteed that a removal function is constant in the polishing process. An additional follow-up device is not needed, the equipment cost is lower, the flow change is small, and the flow fluctuation of the magnetorheological fluid is more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetorheological polishing, and particularly to a magnetorheological polishing device and a polishing method thereof based on the perception of an electromagnetic flowmeter. Background Art

[0002] Magnetorheological Finishing (MRF) is an advanced optical manufacturing and processing technology developed in recent years. It has many advantages such as a stable removal function, controllable edge effect, small damage layer on the lower surface, no copying effect, strong shaping ability, and high processing accuracy. Therefore, the magnetorheological polishing technology has received extensive attention in high-precision optical processing. The existing magnetorheological polishing technology mainly integrates the magnetorheological polishing module on a numerical control machine tool. The supply system of the magnetorheological polishing module mainly uses a centrifugal pump as the supply source. However, there is still a major problem with using a centrifugal pump as the supply source of the supply system: when the nozzle of the magnetorheological polishing module processes along the curved surface of the optical element, the nozzle will move up and down with the tool end of the industrial robot in the working area. When the position of the centrifugal pump is constant, the pressure between the centrifugal pump and the nozzle will change, and the originally stable magnetorheological fluid will also change, resulting in a change in the removal function and affecting the final processing accuracy. [[ID=_{1}0]]

[0003] To address this problem, the commonly used method at present is to add a follow-up device to keep the vertical distance between the centrifugal pump and the liquid outlet of the nozzle unchanged. However, this method requires an additional follow-up device with high motion performance to always keep the vertical distance between the centrifugal pump and the liquid outlet of the nozzle unchanged. Some solutions even place the follow-up device on the Z-axis of the numerical control machine tool, which undoubtedly increases the motion load of the motion mechanism and the equipment cost, reduces the motion performance of the equipment, and the follow-up device cannot strictly ensure that the vertical distance between the centrifugal pump and the liquid outlet of the nozzle is constant. Therefore, the height difference between the centrifugal pump and the nozzle often changes at all times, affecting the stability of the magnetorheological fluid in the magnetorheological supply system, resulting in a change in the removal function during the processing, affecting the processing result, and increasing the equipment cost. Summary of the Invention

[0004] The purpose of the present invention is to provide a magnetorheological polishing device and a polishing method thereof based on the perception of an electromagnetic flowmeter to solve the problem that the removal function cannot be ensured to be constant during the processing even with the addition of a follow-up device in the prior art.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows: A magnetorheological polishing device based on the perception of an electromagnetic flowmeter, comprising: A polishing platform, on which a component to be polished and a test polishing component are provided; A polishing assembly, comprising 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 or 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 and a liquid pump. The magnetorheological mounting frame is installed at the tool end of the industrial robot. The polishing wheel, the nozzle 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 element or the element to be polished. An electromagnetic flowmeter is arranged on the industrial robot and is used to monitor the flow rate of the magnetorheological fluid at the liquid outlet of the nozzle. A laser tracker is arranged on one side of the polishing platform and is used in cooperation with a target ball to measure the vertical distance between the nozzle and the liquid pump. A computer is used to respectively establish a first conversion relationship between the vertical distance and the rotational speed of the liquid pump, a second conversion relationship between the vertical distance and the flow rate of the magnetorheological fluid, and a third conversion relationship between the position of the magnet or the position of the polishing wheel and the flow rate of the magnetorheological fluid according to the flow rate of the magnetorheological fluid monitored by the electromagnetic flowmeter. And the computer is used to respectively adjust the rotational speed of the liquid pump, the pose of the industrial robot, and the position of the magnet or the position of the polishing wheel according to the first conversion relationship to the third conversion relationship to keep the removal function of each polishing point of the element to be polished constant.

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

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

[0008] A magnetorheological polishing method based on the pose adjustment of an industrial robot, which is realized by using the above-mentioned magnetorheological polishing equipment based on the perception of an electromagnetic flowmeter, includes the following steps: S1: Set the theoretical initial values of the liquid pump speed and the corresponding magnetorheological fluid flow rate for each polishing point of the test polishing element, polish the test polishing element, change the vertical distance between the liquid pump and the nozzle, measure the magnetorheological fluid flow rate corresponding to different vertical distances through an electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the liquid pump speed so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the liquid pump speed, and obtain the first conversion relationship between the vertical distance and the liquid pump speed through data fitting; among them, the first conversion relationship is expressed as , represents the liquid pump speed, represents the vertical distance, represents the conversion relationship between the vertical distance and the liquid pump speed; And at each vertical distance, set different polishing gaps, measure the magnetorheological fluid flow rate corresponding to different polishing gaps at each vertical distance through an electromagnetic flowmeter, obtain the discrete data of the polishing gap and the magnetorheological fluid flow rate at each vertical distance, and obtain the second conversion relationship between the polishing gap and the corresponding magnetorheological fluid flow rate at each vertical distance through data fitting. The second conversion relationship can be expressed as , where represents the polishing gap at each vertical distance, represents the magnetorheological fluid flow rate corresponding to the polishing gap at each vertical distance, represents the conversion relationship between the polishing gap and the magnetorheological fluid flow rate at each vertical distance; S2: According to the surface height change of the element to be polished, calculate the change of the liquid pump speed based on the first conversion relationship to obtain the theoretical liquid pump speed corresponding to each polishing point of the element to be polished. Polish the element to be polished according to the theoretical liquid pump speed of each polishing point, and at the same time, monitor the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to each polishing point in real time through an electromagnetic flowmeter and send it to the computer; among them, the theoretical liquid pump speed is expressed as , where represents the theoretical liquid pump speed of each polishing point, i = 1, 2, 3... m, m represents the number of polishing points, represents the vertical distance of the i-th polishing point; S3: Set the flow rate fluctuation tolerance range in the computer, judge whether the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to each polishing point exceeds the set flow rate fluctuation tolerance range. If it does not exceed, keep the polishing gap of the polishing point unchanged. If it exceeds, adjust the pose of the industrial robot according to the adjustment amount of the polishing gap to change the polishing gap of the polishing point until the actual magnetorheological fluid flow rate does not exceed the flow rate fluctuation tolerance range to maintain the removal function of each polishing point constant.

[0009] Further, when polishing each polishing point of the polishing element, a dwell time is set for each polishing point, and the specific steps are as follows: S210: Establish a measurement coordinate system of the laser tracker so that the measurement coordinate system is parallel to the tool coordinate system of the industrial robot; S220: Drive the industrial robot to move towards the polishing platform so that the lowest point of the polishing wheel just touches the polishing platform. Place the target ball at the liquid outlet of the nozzle and measure the Z-axis coordinate Z4 of the target ball at this time; S230: Place the target ball on the polishing platform near the lowest point of the polishing wheel and measure the Z-axis coordinate of the target ball at this time , then the vertical distance between the nozzle and the lowest point of the polishing wheel is , and the time required for the magnetorheological fluid ejected by the magnetorheological supply system to reach the lowest point of the polishing wheel is , where represents the number of revolutions per second of the polishing wheel, represents the length of the pipeline between the electromagnetic flowmeter and the nozzle, represents the flow rate of the magnetorheological fluid, represents the radius of the polishing wheel.

[0010] Further, when the computer generates a polishing control program, if the dwell time of each polishing point is, then the generated polishing control program is appropriate; if there is a dwell time of a certain polishing point , then extend the dwell time of this polishing point , and regenerate the polishing control program so that the dwell time of each polishing point .

[0011] Further, in step S3, the maximum adjustment amount of the Z-axis regulation amount of the industrial robot is set in the computer to be ; and, If the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to the current polishing point is within the set flow rate fluctuation tolerance range , keep the polishing gap of the polishing point unchanged; If the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the Z-axis coordinate adjustment amount of the current industrial robot [[ID=5)]], then adjust the Z-axis coordinate of the current industrial robot according to the following formula : ; If the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the adjustment amount of the Z-axis coordinate of the current industrial robot , then adjust the Z-axis coordinate of the industrial robot according to the following formula : ; wherein, represents the initial Z-axis coordinate of the industrial robot

[0012] A magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position, which is realized by using the above-mentioned magnetorheological polishing equipment based on the electromagnetic flowmeter perception, and includes the following steps: S1: Set the theoretical initial values of the liquid pump speed and the corresponding magnetorheological fluid flow rate at each polishing point of the test polishing element, polish the test polishing element, change the vertical distance between the liquid pump and the nozzle, measure the magnetorheological fluid flow rate corresponding to different vertical distances through the electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the liquid pump speed so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the liquid pump speed, and obtain the first conversion relationship between the vertical distance and the liquid pump speed through data fitting; wherein, the first conversion relationship is expressed as , represents the liquid pump speed, represents the vertical distance, represents the conversion relationship between the vertical distance and the liquid pump speed; And at each vertical distance, set different polishing gaps, set different magnet positions or polishing wheel positions at each polishing gap, measure the magnetorheological fluid flow rate corresponding to different positions of the magnet or the polishing wheel at each polishing gap through the electromagnetic flowmeter, obtain the discrete data of the magnet or the polishing wheel at different positions and the corresponding magnetorheological fluid flow rate at each polishing gap, and obtain the third conversion relationship between the magnet or the polishing wheel at different positions and the corresponding magnetorheological fluid flow rate at each polishing gap through data fitting. The third conversion relationship can be expressed as , wherein, represents the magnet position or the polishing wheel position, represents the magnetorheological fluid flow rate corresponding to different positions of the magnet or the polishing wheel at each polishing gap, represents the conversion relationship between the magnet or the polishing wheel at different positions and the magnetorheological fluid flow rate at each vertical distance; S2: According to the height change of the curved surface of the element to be polished, calculate the change in the rotational speed of the liquid pump based on the first conversion relationship, obtain the theoretical rotational speed of the liquid pump corresponding to each polishing point of the element to be polished, polish the element to be polished according to the theoretical rotational speed of each polishing point, and simultaneously monitor the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point in real time through an electromagnetic flowmeter and send it to the computer; where the theoretical rotational speed of the liquid pump is expressed as , where represents the theoretical rotational speed of the liquid pump at each polishing point, i = 1, 2, 3…m, m represents the number of polishing points, represents the vertical distance of the i-th polishing point; S3: Set the allowable range of flow rate fluctuation in the computer, and determine whether the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point exceeds the set allowable range of flow rate fluctuation. If it does not exceed, keep the position of the magnet or the position of the polishing wheel unchanged at the polishing point. If it exceeds, the position adjustment device adjusts the position of the magnet or the position of the polishing wheel according to the adjustment amount of the position of the magnet or the position of the polishing wheel until the actual flow rate of the magnetorheological fluid does not exceed the allowable range of flow rate fluctuation, so as to maintain the removal function of each polishing point constant.

[0013] Further, when polishing each polishing point of the element to be polished, a dwell time is set for each polishing point, which specifically includes the following steps: S210: Establish a measurement coordinate system of the laser tracker so that the measurement coordinate system is parallel to the tool coordinate system of the industrial robot; S220: Drive the industrial robot to move towards the polishing platform so that the lowest point of the polishing wheel just touches the polishing platform, place the target ball at the liquid outlet of the nozzle and measure the Z-axis coordinate Z4 of the target ball at this time; S230: Place the target ball on the polishing platform near the lowest point of the polishing wheel and measure the Z-axis coordinate of the target ball at this time , then the vertical distance between the nozzle and the lowest point of the polishing wheel is , and the time required for the magnetorheological fluid ejected by the magnetorheological supply system to reach the lowest point of the polishing wheel is , where represents the number of revolutions per second of the polishing wheel, represents the length of the pipeline between the electromagnetic flowmeter and the nozzle, represents the flow velocity of the magnetorheological fluid, represents the radius of the polishing wheel.

[0014] Further, when the computer generates a polishing control program, if the dwell time of each polishing point then the generated polishing control program is appropriate; if there is a dwell time of a certain polishing point , then extend the dwell time of this polishing point , regenerate the polishing control program so that the dwell time of each polishing point .

[0015] Furthermore, in step S3, set the maximum adjustment amount of the magnet position or the polishing wheel position in the computer to be ; and, If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is within the set flow rate fluctuation tolerance range , keep the magnet position or the polishing wheel position unchanged; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the adjustment amount of the current magnet position or the polishing wheel position , then adjust the current magnet position or the polishing wheel position according to the following formula: ; where, represents the current magnet position or the polishing wheel position; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the adjustment amount of the current magnet position or the polishing wheel position , then adjust the magnet position or the polishing wheel position according to the following formula: ; where, represents the initial position of the magnet or the polishing wheel.

[0016] Compared with the prior art, the present invention uses an electromagnetic flowmeter to measure the change in the flow rate of the magnetorheological fluid during the polishing process, and realizes the coarse and fine two-stage regulation of the flow rate fluctuation of the magnetorheological fluid by controlling the rotational speed of the liquid pump and controlling the magnet position or the polishing wheel position, so that the flow rate fluctuation of the magnetorheological fluid at each polishing point meets the high-precision polishing requirements and ensures the constancy of the removal function during the polishing process. The present invention does not require an additional follow-up device, has a lower equipment cost, a small flow rate change, and a more stable flow rate fluctuation of the magnetorheological fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the magnetorheological polishing device based on electromagnetic flowmeter sensing according to an embodiment of the present invention from one perspective; Figure 2 is a schematic structural diagram of the magnetorheological polishing device based on electromagnetic flowmeter sensing according to an embodiment of the present invention from another perspective; Figure 3Schematic structural diagram of the magnetorheological polishing module according to an embodiment of the present invention from one perspective; Figure 4 Schematic structural diagram of the magnetorheological polishing module according to an embodiment of the present invention from another perspective; Figure 5 Schematic structural diagram of the position adjustment device according to an embodiment of the present invention.

[0018] Reference numerals: polishing platform 1, element to be polished 101, test polishing element 102, industrial robot 201, magnetorheological mounting bracket 202, polishing wheel 203, magnet 204, nozzle 205, liquid pump 206, support fixing bracket 207, ball screw stepping motor 208, connecting plate 209, drive motor 210, driving pulley 211, driven pulley 212, synchronous belt 213, lead screw 214, guide rail 215, slider 216, nut 217, position adjustment device 218, mounting bracket 219, electromagnetic flowmeter 3, laser tracker 4, target ball 401, computer 5. Detailed implementation manners

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

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

[0021] In a first aspect, the present embodiment provides a magnetorheological polishing device based on electromagnetic flowmeter sensing. The structure of the device is as Figures 1 - 5 shown and includes: A polishing platform 1, on which an element to be polished 101 and a test polishing element 102 are provided; A polishing component, which includes an industrial robot 201 and a magnetorheological polishing module. The industrial robot 201 is used to drive the magnetorheological polishing module to move to the position where the test polishing element 102 is located or drive the magnetorheological polishing module to move to the position where the element to be polished 101 is located; the magnetorheological polishing module is used to polish the element to be polished 101 or the test polishing element 102. The magnetorheological polishing module includes a magnetorheological mounting frame 202, a polishing wheel 203, a magnet 204, a nozzle 205, a liquid pump 206, two sets of position adjustment devices 218 and a set of polishing wheel driving devices. The magnetorheological mounting frame 202 is installed at the tool end of the industrial robot 201. The polishing wheel driving device is installed on the magnetorheological mounting frame 202 and is used to drive the polishing wheel 203 to rotate to polish the element to be polished 101 or the test polishing element 102; the nozzle 205 is installed on the magnetorheological mounting frame 202 and is used to spray magnetorheological fluid onto the polishing wheel 203; the liquid pump 206 is installed on the industrial robot 201 or on the mounting bracket 219 on one side of the industrial robot 201. The liquid pump 206 is connected to the nozzle 205 through a pipeline and is used to pump magnetorheological fluid into the nozzle 205. The liquid pump 206 selects the DFLD vertical multistage pump of Shanghai Dongfang Pump Industry Company; the two sets of position adjustment devices 218 are respectively installed on the magnetorheological mounting frame 202. One set of position adjustment device 218 is used to adjust the position of the magnet 204, and the magnet 204 is used to change the stiffness of the magnetorheological fluid; the other set of position adjustment device 218 is used to adjust the position of the polishing wheel 203; An electromagnetic flowmeter 3, which is arranged on the industrial robot 201 and is used to monitor the flow rate of the magnetorheological fluid at the liquid outlet of the nozzle 205; A laser tracker 4, which is arranged on one side of the polishing platform 1 and is used in cooperation with the target ball 401 to measure the vertical distance (hereinafter referred to as the vertical distance) between the nozzle 205 and the liquid pump 206; A computer 5, which is used to establish a first conversion relationship between the vertical distance and the rotational speed of the liquid pump 206, a second conversion relationship between the vertical distance and the flow rate of the magnetorheological fluid, and a third conversion relationship between the position of the magnet 204 or the position of the polishing wheel 203 and the flow rate of the magnetorheological fluid respectively according to the flow rate of the magnetorheological fluid monitored by the electromagnetic flowmeter 3. And the computer 5 is used to adjust the rotational speed of the liquid pump 206, the pose of the industrial robot 201 and the position of the magnet 204 or the position of the polishing wheel 203 respectively according to the first conversion relationship to the third conversion relationship to maintain the removal function of each polishing point of the element to be polished 101 constant.

[0022] The structures of the two sets of position adjustment devices 218 are the same, and each includes a support fixing frame 207, a ball screw stepping motor 208, and a connecting plate 209. The ball screw stepping motor 208 is vertically installed on the magnetorheological mounting frame 202 through the support fixing frame 207. The nut 217 of the ball screw stepping motor 208 is fixedly connected to the connecting plate 209. The magnet 204 and the polishing wheel ²⁰³ are respectively connected to the connecting plates 209 of the two sets of position adjustment devices. The ball screw stepping motors 208 of the two sets of position adjustment devices 218 drive the magnet 204 and the polishing wheel 203 to adjust their positions.

[0023] The polishing wheel driving device includes a driving motor 210, a driving wheel 211, a driven wheel 212, and a synchronous belt 213. The driving motor 210 is installed on the connecting plate 209. A bearing seat is installed on the connecting plate 209. A bearing is installed in the bearing seat. The bearing is connected to the polishing wheel 203. The driven wheel 212 is sleeved on the bearing. The driving wheel 211 is sleeved on the output end of the driving motor 210. The synchronous belt 213 is tensioned between the driven wheel 212 and the driving wheel 211. The driving motor 210 drives the polishing wheel 203 to rotate. For details, reference can be made to the Chinese patent with the publication date of July 12, 2024 and the publication number of CN118322074A.

[0024] In the embodiment of the present invention, to ensure that the polishing wheel 203 and the magnet 204 can move stably along the screw rod 214 of the ball screw stepping motor 208, it is preferably to install a guide rail 215 on each side of the screw rod 214 on the support fixing frame 228, and the two guide rails 215 are parallel to the screw rod 214. A slider 216 is slidably connected to the two guide rails 215. At this time, the connecting plate 209 is fixedly connected to the nut 217 and the two sliders 216 at the same time. During polishing, the computer 5 sends a control signal to the ball screw stepping motor 208, and the ball screw stepping motor 208 drives the connecting plate 209 to move linearly under the sliding cooperation of the guide rail 215 and the slider 216.

[0025] 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.

[0026] In the second aspect, this embodiment also provides a magnetorheological polishing method based on the pose adjustment of an industrial robot, which is implemented by using the above-mentioned magnetorheological polishing equipment based on electromagnetic flowmeter sensing, and includes the following steps: S1: Set the theoretical initial values of the liquid pump speed and the corresponding magnetorheological fluid flow rate for each polishing point of the test polishing element, polish the test polishing element, change the vertical distance between the liquid pump and the nozzle, measure the magnetorheological fluid flow rate corresponding to different vertical distances through an electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the liquid pump speed so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the liquid pump speed, and obtain the first conversion relationship between the vertical distance and the liquid pump speed through data fitting; among them, the first conversion relationship is expressed as , represents the liquid pump speed, represents the vertical distance, represents the conversion relationship between the vertical distance and the liquid pump speed; And at each vertical distance, set different polishing gaps, measure the magnetorheological fluid flow rate corresponding to different polishing gaps at each vertical distance through an electromagnetic flowmeter, obtain the discrete data of the polishing gap and the magnetorheological fluid flow rate at each vertical distance, and obtain the second conversion relationship between the polishing gap and the corresponding magnetorheological fluid flow rate at each vertical distance through data fitting. The second conversion relationship can be expressed as , where represents the polishing gap at each vertical distance, represents the magnetorheological fluid flow rate corresponding to the polishing gap at each vertical distance, represents the conversion relationship between the polishing gap and the magnetorheological fluid flow rate at each vertical distance.

[0027] The purpose of step S1 is to establish the first conversion relationship between the vertical distance and the liquid pump speed and the second conversion relationship between the polishing gap and the corresponding magnetorheological fluid flow rate at each vertical distance by using an electromagnetic flowmeter, specifically as follows: Set the theoretical initial value of the liquid pump speed and the theoretical initial value of the corresponding magnetorheological fluid flow rate for each polishing point of the test polishing element, set the vertical distance between the liquid pump and the nozzle at at least 10 different values, measure the magnetorheological fluid flow rate corresponding to different vertical distances through an electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the liquid pump speed so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the liquid pump speed, and perform data fitting using the Polyfit instruction in Matlab (this instruction is a basic general instruction in the matlab software) to obtain the first conversion relationship; At each vertical distance, the polishing gap is set at at least 10 different values, and the polishing gap and the corresponding magnetorheological fluid flow rate at different vertical distances are measured by an electromagnetic flowmeter to obtain discrete data of the polishing gap and the corresponding magnetorheological fluid flow rate at each vertical distance. The Polyfit instruction of Matlab (this instruction is a basic general instruction of the Matlab software) is used for data fitting to obtain the second conversion relationship.

[0028] S2: According to the surface height change of the element to be polished, based on the first conversion relationship, calculate the change in the liquid pump speed, obtain the theoretical liquid pump speed corresponding to each polishing point of the element to be polished, polish the element to be polished according to the theoretical liquid pump speed of each polishing point, and at the same time, the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to each polishing point is monitored in real time by an electromagnetic flowmeter and sent to the computer; among them, the theoretical liquid pump speed is expressed as , where represents the theoretical liquid pump speed of each polishing point, i = 1, 2, 3…m, m represents the number of polishing points, represents the vertical distance of the i-th polishing point.

[0029] The surface height change of the element to be polished reflects the change in the vertical distance between the liquid pump and the nozzle. According to the height of each polishing point on the surface of the element to be polished, the theoretical liquid pump speed of each polishing point is calculated using the first conversion relationship, and the liquid pump speed is adjusted in real time according to the theoretical liquid pump speed of each polishing point, completing the rough adjustment of the magnetorheological fluid flow rate change during the large-range height movement of the entire surface when the polishing equipment polishes the element to be polished.

[0030] Since the magnetorheological fluid measured by the electromagnetic flowmeter needs to be transported through the pipeline and driven by the polishing wheel to reach the working area of the polishing wheel, the current flow of the magnetorheological fluid will reach the working area of the polishing wheel after a period of time. In order to ensure the adjustment of the removal function change at each polishing point, it is necessary to set the residence time of the polishing point. The specific setting method is as follows: S210: Establish the measurement coordinate system of the laser tracker so that the measurement coordinate system is parallel to the tool coordinate system of the industrial robot.

[0031] S220: Drive the industrial robot to move towards the test bench so that the lowest point of the polishing wheel just touches the test bench, place the target ball of the laser tracker at the liquid outlet of the nozzle and measure the Z-axis coordinate Z4 of the target ball at this time.

[0032] S230: Place the target ball on the polishing platform near the lowest point of the polishing wheel and measure the Z-axis coordinate of the target ball at this time , then the vertical distance between the nozzle and the lowest point of the polishing wheel is , The Z-axis coordinate obtained by placing the target ball on the nozzle, and the time required for the magnetorheological fluid ejected by the magnetorheological supply system to reach the lowest point of the polishing wheel is , where represents the number of revolutions per second of the polishing wheel, represents the length of the pipeline between the electromagnetic flowmeter and the nozzle, represents the flow rate of the magnetorheological fluid, represents the radius of the polishing wheel.

[0033] When the computer generates the polishing control program, if the dwell time of each polishing point then the generated polishing control program is appropriate; if there is a dwell time of a certain polishing point , then extend the dwell time of this polishing point , and regenerate the polishing control program so that the dwell time of each polishing point .

[0034] S3: Set the allowable range of flow rate fluctuations in the computer, and judge whether the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to each polishing point exceeds the set allowable range of flow rate fluctuations. If it does not exceed, keep the polishing gap of the polishing point unchanged. If it exceeds, adjust the pose of the industrial robot according to the adjustment amount of the polishing gap to change the polishing gap of the polishing point until the actual magnetorheological fluid flow rate does not exceed the allowable range of flow rate fluctuations, so as to maintain the removal function of each polishing point constant.

[0035] Since the polishing of optical elements is a variable-speed movement of the polishing equipment, the movement speeds between two adjacent polishing points are often not the same. There is often a situation where the theoretical polishing position does not match the actual polishing position during the process from one polishing point to the next polishing point, the magnetorheological fluid flow rate fluctuates, and the removal function changes.

[0036] Therefore, it is necessary to set the allowable range of magnetorheological fluid flow rate fluctuations in the computer, is the lower limit value of the magnetorheological fluid flow rate fluctuation, is the upper limit value of the magnetorheological fluid flow rate fluctuation.

[0037] During the polishing process, the actual magnetorheological fluid flow rate value at the liquid outlet of the nozzle corresponding to each polishing point is measured in real time by the electromagnetic flowmeter. If the measured actual magnetorheological fluid flow rate value is within range, then the magnetorheological fluid flow rate fluctuation meets the high-precision polishing requirements, and the measurement data does not need to be output and processed. If the measured actual magnetorheological fluid flow rate value is not within If it is not within the range, the fluctuation of the magnetorheological fluid flow does not meet the requirements of high-precision polishing. The measured data needs to be output to a computer for processing, and the data processed by the computer is sent to an industrial robot. Finally, the change in the magnetorheological fluid flow is regulated by adjusting the Z-axis coordinate of the industrial robot to maintain a constant removal function.

[0038] To ensure polishing safety, the maximum adjustment wheel of the Z-axis regulation amount of the industrial robot needs to be set in the computer to , place the component to be polished on the polishing platform and fix it, drive the polishing equipment to polish the component to be polished, and at the same time use an electromagnetic flowmeter to measure the actual magnetorheological fluid flow at the liquid outlet of the nozzle .

[0039] If the actual magnetorheological fluid flow at the liquid outlet of the nozzle corresponding to the current polishing point is within the set allowable range of flow fluctuation , keep the polishing gap at the polishing point unchanged; If the actual magnetorheological fluid flow at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set allowable range of flow fluctuation and the adjustment amount of the Z-axis coordinate of the current industrial robot , then adjust the Z-axis coordinate of the current industrial robot according to the following formula : ; If the actual magnetorheological fluid flow at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set allowable range of flow fluctuation and the adjustment amount of the Z-axis coordinate of the current industrial robot , then adjust the Z-axis coordinate of the industrial robot according to the following formula : ; Among them, represents the initial Z-axis coordinate of the industrial robot.

[0040] By adjusting the pose of the industrial robot (i.e., adjusting the Z-axis coordinate), the polishing gap between the polishing wheel and the component to be polished is changed, and the precise adjustment of the small-range change in the magnetorheological fluid flow is completed, so that the fluctuation of the magnetorheological fluid flow at each polishing point meets the requirements of high-precision polishing and ensures the constancy of the removal function during the polishing process.

[0041] Compared with the current mainstream real-time control scheme for the flow rate change of the magnetorheological fluid supply system based on a follow-up device, the present invention uses an electromagnetic flowmeter to measure the flow rate change during the polishing process of the polishing equipment and realizes coarse and fine two-stage regulation of the flow rate fluctuation by controlling the rotational speed of the liquid pump and the pose of the industrial robot, thereby realizing the real-time control of the change of the removal function. Without the need for an additional follow-up device, the equipment cost is lower, the flow rate change is small, and the flow rate fluctuation of the magnetorheological fluid is more stable.

[0042] In a third aspect, the present embodiment further provides a magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position, which is realized by using the above-mentioned magnetorheological polishing equipment based on the electromagnetic flowmeter perception, and includes the following steps: S1: Set the theoretical initial values of the rotational speed of the liquid pump and the corresponding magnetorheological fluid flow rate at each polishing point of the test polishing element, polish the test polishing element, change the vertical distance between the liquid pump and the nozzle, measure the magnetorheological fluid flow rate corresponding to different vertical distances through the electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the rotational speed of the liquid pump so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the rotational speed of the liquid pump, and obtain the first conversion relationship between the vertical distance and the rotational speed of the liquid pump through data fitting; where the first conversion relationship is expressed as , represents the rotational speed of the liquid pump, represents the vertical distance, represents the conversion relationship between the vertical distance and the rotational speed of the liquid pump; And at each vertical distance, set different polishing gaps, set different magnet positions or polishing wheel positions at each polishing gap, measure the magnetorheological fluid flow rate corresponding to different positions of the magnet or the polishing wheel at each polishing gap through the electromagnetic flowmeter, obtain the discrete data of the different positions of the magnet or the polishing wheel and the corresponding magnetorheological fluid flow rate at each polishing gap, and obtain the third conversion relationship between the different positions of the magnet or the polishing wheel and the corresponding magnetorheological fluid flow rate at each polishing gap through data fitting. The third conversion relationship can be expressed as , where represents the magnet position or the polishing wheel position, represents the magnetorheological fluid flow rate corresponding to different positions of the magnet or the polishing wheel at each polishing gap, represents the conversion relationship between the different positions of the magnet or the polishing wheel and the magnetorheological fluid flow rate at each vertical distance.

[0043] At different polishing gaps and vertical distances, by changing the magnet position or the polishing wheel position, make the removal function constant, and then collect each data to obtain the complete third conversion relationship between the different positions of the magnet or the polishing wheel and the corresponding magnetorheological fluid flow rate at each polishing gap, which is convenient for subsequent parameter regulation.

[0044] The different polishing gaps refer to the situation where the relative distance between the polishing wheel and the magnet remains unchanged, while the distance between the entire magnetorheological polishing module and the workpiece to be polished changes.

[0045] The purpose of step S1 is to establish a first conversion relationship between the vertical distance and the rotational speed of the liquid pump, as well as a third conversion relationship between the magnet or the polishing wheel at different positions and the corresponding magnetorheological fluid flow rate under each polishing gap, specifically as follows: Set the theoretical initial values of the rotational speed of the liquid pump and the theoretical initial values of the corresponding magnetorheological fluid flow rate at each polishing point of the test polishing element. Set the vertical distance between the liquid pump and the nozzle at at least 10 different values. Measure the magnetorheological fluid flow rate corresponding to different vertical distances through the electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the rotational speed of the liquid pump so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtaining discrete data of the vertical distance and the rotational speed of the liquid pump. Use the Polyfit instruction in Matlab (this instruction is a basic general instruction in the Matlab software) to perform data fitting to obtain the first conversion relationship; Under each polishing gap, set the magnet position or the polishing wheel position at at least 10 different values. Measure the magnet position and the corresponding magnetorheological fluid flow rate or the polishing wheel position and the corresponding magnetorheological fluid flow rate under different polishing gaps through the electromagnetic flowmeter, obtaining discrete data of the magnet position and the corresponding magnetorheological fluid flow rate or discrete data of the polishing wheel position and the corresponding magnetorheological fluid flow rate under each polishing gap. Use the Polyfit instruction in Matlab (this instruction is a basic general instruction in the Matlab software) to perform data fitting to obtain the third conversion relationship.

[0046] S2: According to the height changes of the curved surface of the workpiece to be polished, calculate the change in the rotational speed of the liquid pump based on the first conversion relationship to obtain the theoretical rotational speed of the liquid pump corresponding to each polishing point of the workpiece to be polished. Polish the workpiece to be polished according to the theoretical rotational speed of each polishing point. At the same time, monitor the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to each polishing point in real time through the electromagnetic flowmeter and send it to the computer; where the theoretical rotational speed of the liquid pump is expressed as , where represents the theoretical rotational speed of the liquid pump at each polishing point, i = 1, 2, 3... m, m represents the number of polishing points, represents the vertical distance of the i-th polishing point.

[0047] The height variation of the curved surface of the element to be polished reflects the variation of the vertical distance between the liquid pump and the nozzle. According to the height of each polishing point on the curved surface of the element to be polished, the theoretical liquid pump speed of each polishing point is calculated using the first conversion relationship, and the liquid pump speed is adjusted in real time according to the theoretical liquid pump speed of each polishing point, completing the rough adjustment of the large-range removal function flow rate variation of the entire curved surface height movement during the polishing of the element to be polished by the polishing equipment.

[0048] Since the magnetorheological fluid measured by the electromagnetic flowmeter needs to be transported through the pipeline and driven by the polishing wheel to reach the working area of the polishing wheel, the magnetorheological fluid of the current flow rate will reach the working area of the polishing wheel after a period of time. In order to ensure the adjustment of the removal function variation at each polishing point, the residence time of the polishing point needs to be set. The specific setting method is as follows: S210: Establish the measurement coordinate system of the laser tracker so that the measurement coordinate system is parallel to the tool coordinate system of the industrial robot.

[0049] S220: Drive the industrial robot to move towards the test bench so that the lowest point of the polishing wheel just touches the test bench, place the target ball of the laser tracker at the liquid outlet of the nozzle and measure the Z-axis coordinate Z4 of the target ball at this time.

[0050] S230: Place the target ball on the polishing platform near the lowest point of the polishing wheel and measure the Z-axis coordinate of the target ball at this time , then the vertical distance between the nozzle and the lowest point of the polishing wheel is , and the time required for the magnetorheological fluid ejected by the magnetorheological supply system to reach the lowest point of the polishing wheel is , where represents the number of revolutions per second of the polishing wheel, represents the pipeline length between the electromagnetic flowmeter and the nozzle, represents the flow rate of the magnetorheological fluid, represents the radius of the polishing wheel.

[0051] When the computer generates the polishing control program, if the residence time of each polishing point is satisfied, the generated polishing control program is appropriate; if there is a residence time of a certain polishing point , then extend the residence time of this polishing point , and regenerate the polishing control program so that the residence time of each polishing point .

[0052] S3: Set the allowable range of flow rate fluctuation in the computer, and determine whether the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point exceeds the set allowable range of flow rate fluctuation. If it does not exceed, keep the position of the magnet or the position of the polishing wheel at the polishing point unchanged. If it exceeds, the position adjustment device adjusts the position of the magnet or the position of the polishing wheel according to the adjustment amount of the magnet position or the polishing wheel position until the actual flow rate of the magnetorheological fluid does not exceed the allowable range of flow rate fluctuation, so as to maintain the constant removal function of each polishing point.

[0053] Since the polishing of optical elements is a variable-speed movement of the polishing equipment, the movement speeds between two adjacent polishing points are often not the same. There is often a situation where the theoretical polishing position does not match the actual polishing position during the process from one polishing point to the next polishing point, resulting in fluctuations in the flow rate of the magnetorheological fluid and changes in the removal function.

[0054] Therefore, it is necessary to set the allowable range of flow rate fluctuation of the magnetorheological fluid during the polishing process in the computer. , is the lower limit value of the flow rate fluctuation of the magnetorheological fluid, is the upper limit value of the flow rate fluctuation of the magnetorheological fluid.

[0055] During the polishing process, the actual flow rate value of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point is measured in real time by an electromagnetic flowmeter. If the measured actual flow rate value of the magnetorheological fluid is within range, the flow rate fluctuation of the magnetorheological fluid meets the requirements of high-precision polishing, and the measurement data does not need to be output and processed. If the measured actual flow rate value of the magnetorheological fluid is not within range, the flow rate fluctuation of the magnetorheological fluid does not meet the requirements of high-precision polishing, and the measurement data needs to be output to the computer for processing. The data processed by the computer is sent to the industrial position adjustment device to adjust the position of the magnet or the position of the polishing wheel to control the change of the flow rate of the magnetorheological fluid and maintain the constant removal function.

[0056] To ensure polishing safety, it is necessary to set the maximum adjustment amount of the polishing wheel position or the magnet position in the computer to Place the component to be polished on the polishing platform and fix it, drive the polishing equipment to polish the component to be polished, and at the same time measure the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle by using an electromagnetic flowmeter. .

[0057] If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is within the set allowable range of flow rate fluctuation , keep the position of the magnet or the position of the polishing wheel unchanged; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set allowable range of flow rate fluctuation and the adjustment amount of the current magnet position or polishing wheel position , then adjust the current magnet position or polishing wheel position according to the following formula: ; wherein, represents the current magnet position or polishing wheel position; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the adjustment amount of the current magnet position or polishing wheel position , then adjust the magnet position or polishing wheel position according to the following formula: ; wherein, represents the initial position of the magnet or polishing wheel.

[0058] Through the position adjustment of the polishing wheel or magnet, the precise adjustment of the small-range change of the magnetorheological fluid flow rate is completed, so that the flow rate fluctuation of the magnetorheological fluid at each polishing point meets the high-precision polishing requirements, and the constancy of the removal function during the polishing process is ensured.

[0059] Compared with the current mainstream real-time control scheme for the flow rate change of the magnetorheological fluid supply system based on the follow-up device, the present invention uses an electromagnetic flowmeter to measure the change of the flow rate during the polishing process of the polishing equipment and realizes the coarse and fine two-stage adjustment of the flow rate fluctuation by controlling the rotation speed of the liquid pump and controlling the magnet position or polishing wheel position, so as to realize the real-time control of the change of the removal function, without the need for an additional follow-up device, with lower equipment cost, smaller flow rate change, and more stable flow rate fluctuation of the magnetorheological fluid.

[0060] It should be understood that the various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps recorded 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.

[0061] 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A magnetorheological polishing device based on the sensing of an electromagnetic flowmeter, characterized in that, Comprising: A polishing platform, on which an element to be polished and a test polishing element are arranged; A polishing assembly, including an industrial robot and a magnetorheological polishing module. The industrial robot is used to drive the magnetorheological polishing module to move to the position where the test polishing element is located or the position where the element to be polished is located. The magnetorheological polishing module is used to polish the element to be polished or the test polishing element. The magnetorheological polishing module includes a magnetorheological mounting frame, a polishing wheel, a nozzle, a magnet and a liquid pump. The magnetorheological mounting frame is installed at the tool end of the industrial robot. The polishing wheel, the nozzle 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 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; An electromagnetic flowmeter, arranged on the industrial robot, for monitoring the flow rate of the magnetorheological fluid at the liquid outlet of the nozzle; A laser tracker, arranged on one side of the polishing platform, used in cooperation with a target ball to measure the vertical distance between the nozzle and the liquid pump; A computer, used to establish a first conversion relationship between the vertical distance and the rotational speed of the liquid pump, a second conversion relationship between the vertical distance and the flow rate of the magnetorheological fluid, and a third conversion relationship between the position of the magnet or the position of the polishing wheel and the flow rate of the magnetorheological fluid respectively according to the flow rate of the magnetorheological fluid monitored by the electromagnetic flowmeter. And the computer is used to adjust the rotational speed of the liquid pump, the pose of the industrial robot and the position of the magnet or the position of the polishing wheel respectively according to the first conversion relationship to the third conversion relationship to keep the removal function of each polishing point of the element to be polished constant.

2. The magnetorheological polishing equipment based on the sensing of an electromagnetic flowmeter according to claim 1, wherein, The magnetorheological polishing module further includes two sets of position adjustment devices. Each set of position adjustment devices includes a support fixing frame, a ball screw stepping motor and a connecting plate. The ball screw stepping motor is vertically installed on the magnetorheological mounting frame through the support fixing frame. The nut of the ball screw stepping motor is fixedly connected with the connecting plate. The magnet and the polishing wheel are respectively connected to the corresponding connecting plates.

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

4. A magnetorheological polishing method based on the pose adjustment of an industrial robot, which is realized by using the magnetorheological polishing equipment sensed by an electromagnetic flowmeter according to claim 1, and is characterized in that, Including the following steps: S1: Set the theoretical initial values of the liquid pump speed and the corresponding magnetorheological fluid flow rate for each polishing point of the test polishing element. Polish the test polishing element, change the vertical distance between the liquid pump and the nozzle, measure the magnetorheological fluid flow rate corresponding to different vertical distances through an electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the liquid pump speed so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the liquid pump speed, and obtain the first conversion relationship between the vertical distance and the liquid pump speed through data fitting; among them, the first conversion relationship is expressed as , represents the liquid pump speed, represents the vertical distance, represents the conversion relationship between the vertical distance and the liquid pump speed; And at each vertical distance, different polishing gaps are set, and the flow rate of the magnetorheological fluid corresponding to different polishing gaps at each vertical distance is measured by an electromagnetic flowmeter, discrete data of the polishing gap and the magnetorheological fluid flow rate at each vertical distance are obtained, and a second conversion relationship between the polishing gap and the corresponding magnetorheological fluid flow rate at each vertical distance is obtained through data fitting. The second conversion relationship can be expressed as , where represents the polishing gap at each vertical distance, represents the flow rate of the magnetorheological fluid corresponding to the polishing gap at each vertical distance, represents the conversion relationship between the polishing gap and the magnetorheological fluid flow rate at each vertical distance; S2: According to the height change of the curved surface of the element to be polished, calculate the change in the rotational speed of the liquid pump based on the first conversion relationship, obtain the theoretical rotational speed of the liquid pump corresponding to each polishing point of the element to be polished, polish the element to be polished according to the theoretical rotational speed of each polishing point, and simultaneously monitor the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point in real time through an electromagnetic flowmeter and send it to the computer; wherein, the theoretical rotational speed of the liquid pump is expressed as , where represents the theoretical rotational speed of the liquid pump at each polishing point, i = 1, 2, 3... m, m represents the number of polishing points, represents the vertical distance of the i-th polishing point; S3: Set a flow rate fluctuation tolerance range in the computer, and judge whether the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point exceeds the set flow rate fluctuation tolerance range. If not, keep the polishing gap of the polishing point unchanged. If it exceeds, adjust the pose of the industrial robot according to the adjustment amount of the polishing gap to change the polishing gap of the polishing point until the actual flow rate of the magnetorheological fluid does not exceed the flow rate fluctuation tolerance range to keep the removal function of each polishing point constant.

5. The magnetorheological polishing method based on the pose adjustment of an industrial robot according to claim 4, wherein, When polishing each polishing point of the element to be polished, a dwell time is set for each polishing point. Specifically, it includes the following steps: S210: Establish a measurement coordinate system for the laser tracker so that the measurement coordinate system is parallel to the tool coordinate system of the industrial robot; S220: Drive the industrial robot to move towards the polishing platform so that the lowest point of the polishing wheel just touches the polishing platform. Place the target ball at the liquid outlet of the nozzle and measure the Z-axis coordinate Z4 of the target ball at this time; S230: Place the target ball on the polishing platform near the lowest point of the polishing wheel and measure the Z-axis coordinate of the target ball at this time. , then the vertical distance between the nozzle and the lowest point of the polishing wheel is , and the time required for the magnetorheological fluid ejected by the magnetorheological supply system to reach the lowest point of the polishing wheel is , where represents the number of revolutions per second of the polishing wheel, represents the length of the pipeline between the electromagnetic flowmeter and the nozzle, represents the flow rate of the magnetorheological fluid, represents the radius of the polishing wheel.

6. The magnetorheological polishing method based on the pose adjustment of an industrial robot according to claim 5, wherein, When a polishing control program is generated by a computer, if the dwell time of each polishing point is the case, the generated polishing control program is appropriate; if there is a dwell time of a certain polishing point , then extend the dwell time of this polishing point , and regenerate the polishing control program so that the dwell time of each polishing point .

7. The magnetorheological polishing method based on the pose adjustment of an industrial robot according to claim 4, characterized in that In step S3, the maximum adjustment amount of the Z-axis adjustment amount of the industrial robot is set in the computer to be ; And, If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is within the set allowable range of flow rate fluctuation the polishing gap at the polishing point remains unchanged; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the allowable tolerance range of the set flow rate fluctuation and the adjustment amount of the Z-axis coordinate of the current industrial robot , then adjust the Z-axis coordinate of the current industrial robot according to the following formula : ； If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the Z-axis coordinate adjustment amount of the current industrial robot , then adjust the Z-axis coordinate of the industrial robot according to the following formula : ； Among them, represents the initial Z-axis coordinate of the industrial robot.

8. A magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position, which is realized by using the magnetorheological polishing equipment based on electromagnetic flowmeter sensing described in claim 2, characterized in that, It includes the following steps: S1: Set the theoretical initial values of the liquid pump speed and the corresponding magnetorheological fluid flow rate for each polishing point of the test polishing element, polish the test polishing element, change the vertical distance between the liquid pump and the nozzle, measure the magnetorheological fluid flow rate corresponding to different vertical distances through an electromagnetic flowmeter. If the magnetorheological fluid flow rate is different from the set theoretical initial value, adjust the liquid pump speed so that the magnetorheological fluid flow rate is the same as the set theoretical initial value, obtain the discrete data of the vertical distance and the liquid pump speed, and obtain the first conversion relationship between the vertical distance and the liquid pump speed through data fitting; among them, the first conversion relationship is expressed as , represents the liquid pump speed, represents the vertical distance, represents the conversion relationship between the vertical distance and the liquid pump speed; And at each vertical distance, different polishing gaps are set, and at each polishing gap, different magnet positions or polishing wheel positions are set. The flow rate of the magnetorheological fluid corresponding to different positions of the magnet or polishing wheel at each polishing gap is measured by an electromagnetic flowmeter, and discrete data of the flow rate of the magnetorheological fluid corresponding to different positions of the magnet or polishing wheel at each polishing gap is obtained. Through data fitting, a third conversion relationship between the positions of the magnet or polishing wheel at different positions and the corresponding flow rate of the magnetorheological fluid at each polishing gap is obtained. The third conversion relationship can be expressed as , where represents the magnet position or the polishing wheel position, represents the flow rate of the magnetorheological fluid corresponding to different positions of the magnet or polishing wheel at each polishing gap, represents the conversion relationship between the positions of the magnet or polishing wheel at different positions and the flow rate of the magnetorheological fluid at each vertical distance; S2: According to the height change of the curved surface of the element to be polished, calculate the change in the rotational speed of the liquid pump based on the first conversion relationship, obtain the theoretical rotational speed of the liquid pump corresponding to each polishing point of the element to be polished, polish the element to be polished according to the theoretical rotational speed of each polishing point, and at the same time, monitor the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to each polishing point in real time through an electromagnetic flowmeter and send it to the computer; where the theoretical rotational speed of the liquid pump is expressed as , where represents the theoretical rotational speed of the liquid pump at each polishing point, i = 1, 2, 3... m, m represents the number of polishing points, represents the vertical distance of the i-th polishing point; S3: Set the allowable range of flow rate fluctuation in the computer, and determine whether the actual magnetorheological fluid flow rate at the liquid outlet of the nozzle corresponding to each polishing point exceeds the set allowable range of flow rate fluctuation. If it does not exceed, keep the magnet position or the polishing wheel position at the polishing point unchanged. If it exceeds, the position adjustment device adjusts the magnet position or the polishing wheel position according to the adjustment amount of the magnet position or the polishing wheel position until the actual magnetorheological fluid flow rate does not exceed the allowable range of flow rate fluctuation, so as to maintain the constant removal function of each polishing point.

9. The magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position according to claim 8, characterized in that, When polishing each polishing point of the element to be polished, set the dwell time for each polishing point, which specifically includes the following steps: S210: Establish a measurement coordinate system for the laser tracker so that the measurement coordinate system is parallel to the tool coordinate system of the industrial robot; S220: Drive the industrial robot to move towards the polishing platform so that the lowest point of the polishing wheel just touches the polishing platform. Place the target ball at the liquid outlet of the nozzle and measure the Z-axis coordinate Z4 of the target ball at this time; S230: Place the target ball on the polishing platform near the lowest point of the polishing wheel and measure the Z-axis coordinate of the target ball at this time , then the vertical distance between the nozzle and the lowest point of the polishing wheel is , and the time required for the magnetorheological fluid ejected by the magnetorheological supply system to reach the lowest point of the polishing wheel is , where represents the number of revolutions per second of the polishing wheel, represents the length of the pipeline between the electromagnetic flowmeter and the nozzle, represents the flow rate of the magnetorheological fluid, represents the radius of the polishing wheel.

10. The magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position according to claim 9, characterized in that, When the computer generates a polishing control program, if the dwell time of each polishing point is as such, the generated polishing control program is appropriate; if there exists a dwell time of a certain polishing point , then extend the dwell time of this polishing point , and regenerate the polishing control program so that the dwell time of each polishing point .

11. The magnetorheological polishing method based on the adjustment of the magnet position or the polishing wheel position according to claim 8, characterized in that, In step S3, the maximum adjustment amount of the magnet position or the polishing wheel position is set in the computer as ; And, If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is within the set allowable flow rate fluctuation range keep the position of the magnet or the position of the polishing wheel unchanged; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set flow rate fluctuation tolerance range and the adjustment amount of the current magnet position or polishing wheel position , then adjust the current magnet position or polishing wheel position according to the following formula: ； Among them, represents the current magnet position or polishing wheel position; If the actual flow rate of the magnetorheological fluid at the liquid outlet of the nozzle corresponding to the current polishing point is not within the set allowable tolerance range of the flow rate fluctuation and the adjustment amount of the current magnet position or polishing wheel position , then adjust the magnet position or polishing wheel position according to the following formula: ； Among them, represents the initial position of the magnet or the polishing wheel.

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