Magnetorheological polishing equipment and method for adjusting machining posture based on machine vision

Abstract

The invention relates to the technical field of optical machining, in particular to magneto-rheological polishing equipment and method for adjusting the machining posture based on machine vision, and the equipment comprises a robot, a control unit, a magneto-rheological machining module and machine vision equipment; the magneto-rheological processing module is arranged at the free end of the robot; the robot drives a polishing wheel in the magneto-rheological machining module to machine the optical element with magneto-rheological fluid as a medium, and machine vision equipment measures the ribbon thickness of the magneto-rheological fluid in the machining process; according to the method, the real-time change of the ribbon thickness of the magnetorheological fluid in the machining process is measured through machine vision equipment, then the machining postures of the robot and the magnetorheological machining module are regulated and controlled in real time, and then real-time constant control over the removal function is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical processing, and particularly relates to a magnetorheological finishing device and method for adjusting the processing posture based on machine vision. Background Technique

[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 damage layer on the lower surface, no copying effect, strong shape correction ability, and high processing accuracy. Therefore, the magnetorheological finishing technology has received extensive attention in high-precision optical processing. The existing magnetorheological finishing equipment mainly includes three major parts in terms of hardware: a motion execution mechanism, a circulation system, and a polishing wheel module. Among them, the motion execution mechanism is mainly a numerical control machine tool, but the numerical control machine tool has some deficiencies (such as low degrees of freedom, large floor area, high cost, etc.) that limit the deviation amount of aspheric surfaces and make it difficult to perform precise pose control along the surface normal. The most important component in the circulation system is the supply source. Peristaltic pumps and centrifugal pumps are the main types of magnetorheological fluid supply sources currently. When a peristaltic pump is working, it will generate a pulse effect, which will affect the stability of the magnetorheological fluid during pipeline transportation and ultimately affect the stability of the removal function. The centrifugal pump has a small pulse effect when working, and the magnetorheological fluid is more stable during pipeline transportation and has a smaller impact on the change of the removal function. Therefore, it is more suitable for use as a magnetorheological supply system. However, there is still a relatively large problem when using a centrifugal pump as the supply source of the magnetorheological fluid supply system: when the water outlet (nozzle) of the supply system moves up and down along the curved surface of the optical element during processing, the pressure between the centrifugal pump and the nozzle will change when the position of the centrifugal pump is constant. The originally stable magnetorheological fluid will also change, and the thickness and width of the ribbon formed by the magnetorheological fluid after passing through the polishing gap will also change accordingly, resulting in a change in the removal function and affecting the final processing accuracy.

[0003] In view of these deficiencies of the numerical control machine tool, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. Six-degree-of-freedom industrial robots have the advantages of high degrees of freedom, small floor area, large processing range, low cost, etc., making up for the deficiencies of the numerical control machine tool. Therefore, when integrating the magnetorheological finishing module into an industrial robot, it is theoretically possible to achieve high-precision processing of large-aperture complex-curved optical elements.

[0004] However, due to factors such as machining, assembly, load, trajectory planning, and reduction ratio, the execution accuracy of the free end of the robot is relatively low, and the polishing gap changes significantly during the machining process. At the same time, the magnetorheological polishing technology is an optical machining technology with a high degree of determinacy of the removal function, and it has high requirements for changes in the polishing gap during the polishing process. Generally, the change in the polishing gap of a magnetorheological numerical control machining center is in the order of dozens of micrometers (PV < 0.1 mm), while the trajectory accuracy of common commercial robots is generally in the sub-millimeter to millimeter range. This leads to a large change in the polishing gap during the machining process, and the thickness of the ribbon will change after the magnetorheological fluid passes through the polishing gap, reducing the determinacy of the removal function and affecting the final machining accuracy. Therefore, the motion accuracy of currently commercial large six-degree-of-freedom industrial robots often fails to meet the requirements of the magnetorheological polishing technology for changes in the removal function during high-precision polishing.

[0005] Regarding the problem of flow rate change in the centrifugal pump supply system, the commonly used method at present is to add a follow-up device to keep the vertical distance between the centrifugal pump and the nozzle outlet unchanged. However, these methods require the additional follow-up device to have high motion performance to always keep the vertical distance from the nozzle unchanged. In some solutions, the follow-up device is even placed on the Z-axis of the numerical control machine tool, which undoubtedly increases the motion load and equipment cost of the motion mechanism, reduces the motion performance of the equipment, and the follow-up device cannot strictly guarantee the constancy of the vertical distance between the centrifugal pump and the nozzle, resulting in changes in the removal function and affecting the final machining accuracy. Summary of the Invention

[0006] In view of this, the present invention aims to provide a magnetorheological polishing device and method for adjusting the machining posture based on machine vision. The machine vision device measures the real-time change in the ribbon thickness of the magnetorheological fluid during the magnetorheological machining process, and then adjusts the machining posture in real time during the optical element machining, so as to achieve real-time constant control of the removal function.

[0007] To achieve the above object, the technical solution of the present invention is realized as follows: A magnetorheological finishing device for adjusting the machining posture based on machine vision, comprising a robot, a control unit, a magnetorheological machining module and a machine vision device; wherein: the magnetorheological machining module is arranged at the free end of the robot; the robot drives the polishing wheel in the magnetorheological machining module to machine an optical element with magnetorheological fluid as the medium, and during the machining process, the machine vision device measures the ribbon thickness of the magnetorheological fluid; the interior of the control unit includes: a time calculation module, which calculates the measurement time of the machine vision device and the adjustment time of the magnetorheological machining module, and adjusts the machine vision device and the magnetorheological machining module according to the measurement time and the adjustment time; a conversion relationship module, which obtains a first conversion relationship according to the ribbon thickness and the polishing gap of the polishing wheel, and obtains a second conversion relationship according to the ribbon thickness and the position of the polishing wheel of the polishing wheel; a machining program module, which obtains a machining program according to the removal function obtained by the magnetorheological machining module and imports the machining program into the magnetorheological machining module; a real-time regulation module, which adjusts the pose of the robot according to the first conversion relationship, or adjusts the position of the polishing wheel according to the second conversion relationship, so as to keep the removal function stable when machining the optical element.

[0008] Furthermore, the magnetorheological machining module further includes a transmission belt, a polishing motor, a nozzle, a supply system, a magnet, a real-time adjustment device and a magnetorheological mounting frame; wherein, the magnetorheological mounting frame is arranged on the free end; the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, and the real-time adjustment device adjusts the position of the polishing wheel; the polishing motor is arranged on the magnetorheological mounting frame and is connected to the polishing wheel through the transmission belt, so that the polishing motor controls the polishing wheel to rotate, and further the polishing wheel machines the optical element; the nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the supply system conveys magnetorheological fluid to the nozzle; the magnet is arranged on the magnetorheological mounting frame, and the magnet is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field intensity of the magnet and changes the stiffness of the magnetorheological fluid.

[0009] Furthermore, the real-time adjustment device includes a displacement output motor, a lead screw and a support fixing frame; wherein, the support fixing frame is arranged on the magnetorheological mounting frame, the displacement output motor is arranged on the support fixing frame, and the displacement output motor is connected to the lead screw arranged on the support fixing frame; the polishing wheel is connected to the nut on the lead screw, so that the lead screw drives the polishing wheel to move; the control unit sends a control signal to the displacement output motor, and when the displacement output motor drives the lead screw to rotate, the lead screw drives the polishing wheel to move.

[0010] Furthermore, the machine vision device, the robot and the displacement output motor are respectively connected to the control unit to form their respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

[0011] A magnetorheological polishing method based on robot pose control, based on the magnetorheological polishing equipment for adjusting the processing pose based on machine vision provided by the present invention, includes the following steps: A1: Control the pose of the robot, drive the polishing wheel to process the test optical element with different polishing gaps, and obtain the first conversion relationship in the conversion relationship module; A2: Set the first variable range of the polishing gap, and obtain the corresponding second variable range of the ribbon thickness according to the first conversion relationship; set the maximum polishing gap, and obtain the corresponding maximum ribbon thickness according to the first conversion relationship; A3: Control the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum polishing gap; A4: Combine the second variable range, the maximum polishing gap and the maximum ribbon thickness to process the optical element to be processed. During the processing, the real-time regulation module adjusts the pose of the robot in real time, and uses the change amount of the polishing gap generated after the adjustment as the input when processing the next processing position, so that the ribbon thickness at the next processing position is within the second variable range.

[0012] Further, in step A1, control the polishing wheel to process the test optical element with different polishing gaps, measure the ribbon thickness in real time through the machine vision device, and obtain in the conversion relationship module: ; Wherein, represents the polishing gap, represents the ribbon thickness, represents the first conversion relationship.

[0013] Further, in step A4, when controlling the polishing wheel to move to the current processing position , compare the current ribbon thickness measured by the machine vision device with the second variable range : If the current ribbon thickness is within the second variable range , there is no need to adjust the current pose of the robot; If the current ribbon thickness is not within the second variable range , it is necessary to adjust the current pose of the robot: If the change amount of the current ribbon thickness is greater than or equal to the maximum ribbon thickness change amount , represents the initial ribbon thickness, represents the maximum ribbon thickness, and adjust the pose of the robot according to the following formula: ; Wherein, represents the position of the free end at the current machining position; represents the position of the free end at the previous machining position, represents the maximum polishing gap, represents the initial polishing gap; If the change amount of the current ribbon thickness is less than the set maximum ribbon thickness change amount , the current polishing gap is adjusted according to the following formula: ; Wherein, represents the polishing gap at the current machining position.

[0014] A magnetorheological polishing method based on the position control of a polishing wheel, based on the magnetorheological polishing equipment for adjusting the machining posture based on machine vision provided by the present invention, includes the following steps: B1: Control the polishing wheel to machine the test optical element with different polishing gaps, and obtain the second conversion relationship in the conversion relationship module; B2: Set the third variable range of the polishing wheel position, and obtain the corresponding fourth variable range of the ribbon thickness according to the second conversion relationship; set the maximum polishing wheel position, and obtain the corresponding maximum ribbon thickness according to the second conversion relationship; B3: Control the time calculation module to adjust the machine vision device and the magnetorheological machining module in combination with the maximum polishing wheel position; B4: Machine the optical element to be machined in combination with the third variable range, the maximum polishing wheel position and the maximum ribbon thickness, and during the machining process, the real-time control module adjusts the polishing wheel position in real time.

[0015] Further, step B1 includes the following steps: B11: Control the polishing wheel to machine the test optical element with different polishing gaps, calculate the volume removal rate of the removal function at each machining position, and at the same time the machine vision device measures the ribbon thickness at each machining position, and obtain in the conversion relationship module: ; Wherein, represents the volume removal rate of the removal function and the ribbon thickness between the third conversion relationship; B12: Independently change the position of the polishing wheel at different polishing gaps, and perform processing on the test optical element to obtain the volume removal rate of the removal function at each processing position, and then obtain in the conversion relationship module: ; wherein, represents the position of the polishing wheel and the fourth conversion relationship between the volume removal rate of the removal function ; B13: According to the third conversion relationship and the fourth conversion relationship, obtain through the following formula: ; wherein, represents the second conversion relationship.

[0016] Furthermore, in step B4, when controlling the polishing wheel to move to the current processing position , compare the current ribbon thickness measured by the machine vision device with the fourth variable range : If the current ribbon thickness is within the fourth variable range , there is no need to adjust the current polishing wheel position ; If the current ribbon thickness is not within the fourth variable range , it is necessary to adjust the current polishing wheel position : If the current ribbon thickness is greater than or equal to the maximum ribbon thickness , adjust the current polishing wheel position to the maximum polishing wheel position ; If the current ribbon thickness is less than the maximum ribbon thickness , adjust the current polishing wheel position according to the following formula: .

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: In the magnetorheological finishing equipment and method for adjusting the machining posture based on machine vision of the present invention, the ribbon thickness of the magnetorheological fluid during the six-dimensional machining process of the robot driving the magnetorheological machining module is measured in real time by the machine vision device, so as to adjust the machining posture of the magnetorheological machining module in real time, and further realize the real-time constant control of the change of the removal function under the coupling of multiple factors during the machining process of the optical element; at the same time, the acquisition of the pose information does not need to depend on the actual machining process, and the pose error information of the machining equipment can be obtained during the trial operation link of machining (no magnetorheological fluid is introduced in this link and no machining effect is generated), and it is not necessary to place the measuring device at the lowest point of the polishing wheel, which will not affect the actual machining. Brief Description of the Drawings

[0018] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 Fig. is a schematic structural diagram of the magnetorheological finishing equipment for adjusting the machining posture based on machine vision according to an embodiment of the present invention from one perspective; Figure 2 Fig. is a schematic diagram of the magnetorheological finishing equipment for adjusting the machining posture based on machine vision according to an embodiment of the present invention from another perspective; Figure 3 Fig. is a schematic structural diagram of the magnetorheological machining module according to an embodiment of the present invention; Figure 4 Fig. is a schematic structural diagram of the real-time adjustment device according to an embodiment of the present invention.

[0019] Description of the Reference Numerals in the Drawings: 1. Robot; 2. Control unit; 3. Machine vision device; 4. Polishing wheel; 5. Test bench; 6. Optical element to be machined; 7. Test optical element; 8. Real-time adjustment device; 9. Transmission belt; 10. Polishing motor; 11. Nozzle; 12. Magnet; 13. Magnetorheological mounting bracket; 14. Support fixing bracket; 15. Displacement output motor; 16. Lead screw; 17. Nut; 18. Guide rail; 19. Slide block; 20. Connecting plate. Detailed Embodiments

[0020] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0021] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0023] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0024] The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0025] As Figures 1 to 2As shown in the figure, the magnetorheological finishing equipment based on machine vision for adjusting the machining posture according to the embodiments of the present invention includes a robot 1, a control unit 2, a magnetorheological machining module, and a machine vision device 3. The magnetorheological machining module is arranged at the free end of the robot 1. The robot 1 drives the polishing wheel 4 in the magnetorheological machining module to place an optical element 6 to be machined or a test optical element 7 on the experimental table 5 with magnetorheological fluid as the medium for machining. During the machining process, the ribbon thickness of the magnetorheological fluid is affected by the supply system providing the magnetorheological fluid and the polishing gap, and the polishing gap is changed by the position of the polishing wheel, the pose adjustment of the robot, etc. Therefore, it is necessary to use the machine vision device 3 installed on one side of the experimental table 5 to measure the change of the ribbon thickness of the magnetorheological fluid in real time. In the embodiments of the present invention, the machine vision device 3 uses a binocular stereo camera of the Stereo ace model of Basler Company. The process of using the machine vision device 3 to measure the ribbon thickness of the magnetorheological fluid includes: the machine vision device 3 collects the contour information of the polishing wheel 4 and the ribbon of the magnetorheological fluid. Taking any point in the non-working area of the surface of the polishing wheel 4 as the reference point and the highest point on the surface of the ribbon of the magnetorheological fluid as the measurement point, the height difference between the measurement point and the reference point is the change data of the ribbon thickness.

[0026] The interior of the control unit 2 includes a time calculation module, a conversion relationship module, and a real-time regulation module. The time calculation module is used to calculate the measurement time of the machine vision device 3 and the adjustment time of the magnetorheological machining module, and adjust the machine vision device 3 and the magnetorheological machining module according to the measurement time and the adjustment time. The conversion relationship module is used to obtain a first conversion relationship according to the ribbon thickness and the polishing gap of the polishing wheel 4, and obtain a second conversion relationship according to the ribbon thickness and the polishing wheel position of the polishing wheel 4. In the embodiments of the present invention, it is stipulated that the polishing wheel position is the distance between the working point of the polishing wheel 4 and the optical element 6 to be machined or the test optical element 7. The working point of the polishing wheel 4 is defined as the closest point along the normal direction of the surface of the optical element 6 to be machined or the test optical element 7 between the polishing wheel 4 and the surface of the optical element 6 to be machined or the test optical element 7. The machining program module is used to obtain a machining program according to the removal function obtained by the magnetorheological machining module and import the machining program into the magnetorheological machining module. The real-time regulation module is used to adjust the pose of the robot 1 or the polishing wheel position of the polishing wheel 4 according to the machining program and the conversion relationship, so as to keep the removal function stable when machining the optical element 6 to be machined or the test optical element 7.

[0027] Figure 3 Figure (a) in shows a schematic structural diagram of the magnetorheological machining module from one perspective, Figure 3 Figure (b) in shows a schematic structural diagram of the magnetorheological machining module from another perspective. As Figure 3As shown, the magnetorheological machining module further includes a real-time adjustment device 8, a transmission belt 9, a motor 10, a nozzle 11, a supply system, a magnet 12, and a magnetorheological mounting bracket 13. The magnetorheological mounting bracket 13 is fixedly installed on the free end of the robot 1. The polishing wheel 4 and the real-time adjustment device 8 are installed on the magnetorheological mounting bracket, and the real-time adjustment device 8 is connected to the polishing wheel 4. Specifically, the head end of the connecting plate 20 is installed on the real-time adjustment device 8, and the polishing wheel 4 is installed at the tail end of the connecting plate 20, so that the real-time adjustment device 8 adjusts the position of the polishing wheel 4, thereby changing the polishing gap of the polishing wheel 4. The polishing motor 10 is mounted on the connecting plate 20. The output end of the polishing motor 10 passes through the connecting plate 20, and the bearing of the polishing wheel 4 passes through the tail end of the connecting plate 20. The output end of the polishing motor 10 is connected to the bearing of the polishing wheel 4 through the transmission belt 9, so that the polishing motor 10 controls the polishing wheel 4 to rotate. In the embodiment of the present invention, the manner in which the polishing motor 10 drives the polishing wheel 4 to rotate can refer to the invention patent application with the Chinese patent publication number CN118322074A, the publication date of July 12, 2024, and the patent name "Self-rotating Polishing Module Processing System". The nozzle 11 is installed on the magnetorheological mounting bracket 13 along the rotation direction of the polishing wheel 4. The supply system conveys the magnetorheological fluid to the nozzle 11, and the nozzle 11 sprays the magnetorheological fluid at the working point of the polishing wheel 4, so that the polishing wheel 4 processes the optical element 6 to be processed or the test optical element 7 with the magnetorheological fluid as the medium. The magnet 12 is fixed on the magnetorheological mounting bracket 13 through the connecting plate 20, and the magnet 12 is close to the working point of the polishing wheel 4, so that the magnetorheological fluid changes its stiffness under the influence of the magnetic field strength of the magnet 12. In addition, in the embodiment of the present invention, the supply system uses the DFLD vertical multistage pump of Shanghai Orient Pump Industry Co., Ltd.

[0028] The structure of the real-time adjustment device 8 that controls the polishing wheel 4 is as Figure 4As shown in the figure, it includes a support fixing frame 14, a displacement output motor 15 and a lead screw 16. The lead screw 16 and the nut 17 with balls thereon together form a ball screw. The support fixing frame 14 is installed on the magnetorheological mounting frame 13. The displacement output motor 15 is installed on the top of the support fixing frame 14. The output end of the displacement output motor 15 is connected to the lead screw 16 installed on the support fixing frame 14. The polishing wheel 4 is connected to the nut 17 on the lead screw 16 through a connecting plate 20, so that the lead screw 16 drives the polishing wheel 4 to move. In the embodiment of the present invention, in order to ensure that the polishing wheel 4 can move stably along the lead screw 16, it is preferably that a guide rail 18 is installed on both sides of the lead screw 16 on the support fixing frame 14, and the two guide rails 18 are parallel to the lead screw 16. At this time, the head end of the connecting plate 20 is fixedly connected to the nut 17 on the lead screw 16 and the sliders 19 on the two guide rails 18 at the same time. During the processing, the control unit 2 sends a control signal to the displacement output motor 15. When the displacement output motor 15 drives the lead screw 16 to rotate, the lead screw 16 cooperates with the two guide rails 18 to pull the connecting plate 20, and then drives the polishing wheel 4 to move up and down.

[0029] The displacement output motors 15 of the robot 1, the machine vision device 3 and the real-time adjustment device 8 are respectively connected to the control unit 2 to form their respective communication lines, so that the control unit 2 receives and sends signals through the corresponding communication lines. Specifically, the control unit 2 receives signals from the machine vision device 3 through the communication line, and the control unit 2 sends a control signal for changing the position of the polishing wheel 4 to the displacement output motor 15 in the real-time adjustment device 8 through the communication line. Since a strong magnetic region is generated around the polishing wheel 4 during the polishing operation, the communication line avoids the strong magnetic region.

[0030] Based on the magnetorheological polishing equipment for adjusting the machining posture based on machine vision described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological polishing method for adjusting the machining posture based on machine vision, including a magnetorheological polishing method based on robot pose control and a magnetorheological polishing method based on polishing wheel position control.

[0031] Specific Embodiment 1: The magnetorheological polishing method based on robot pose control provided in this specific embodiment, according to the magnetorheological polishing equipment for adjusting the machining posture based on machine vision in the embodiment of the present invention, combined with Figures 1 to 4 , includes the following steps: A1: Control the pose of the robot 1 to drive the polishing wheel 4 to process the test optical element 7 with different polishing gaps, and obtain the first conversion relationship in the conversion relationship module. In step A1, control the magnetorheological processing module to process the test optical element 7 with different polishing gaps, and measure the ribbon thickness in real time through the machine vision device 3. In the conversion relationship module, obtain: ; Wherein, represents the polishing gap, represents the ribbon thickness, represents the first conversion relationship. In this specific embodiment, specifically, the magnetorheological machining module is controlled to perform fixed-point machining on the test optical element 7 for a period of time with different polishing gaps.

[0032] A2: Set the first variable range of the polishing gap , and according to the first conversion relationship obtain the second variable range corresponding to the ribbon thickness , that is: ; ; Set the maximum polishing gap , and obtain the maximum polishing gap change amount as: ; Among them, represents the initial polishing gap; According to the first conversion relationship obtain the corresponding maximum ribbon thickness , that is: ; At this time, the maximum ribbon thickness change amount is obtained as : ; Among them, is the set initial ribbon thickness, represents the maximum ribbon thickness.

[0033] The first variable range and the maximum polishing gap are adaptively set according to the actual situation, and this specific embodiment does not limit this.

[0034] A3: Control the time calculation module to adjust the machine vision device 3 and the magnetorheological machining module in combination with the maximum polishing gap. Step A3 includes the following steps: A31. Statistically analyze b data measured by the machine vision device 3 within a seconds to obtain the time for the machine vision device 3 to measure one point ; ; A32. Calculate the time required to adjust the magnetorheological machining module under the maximum polishing gap change amount : ; Among them, Represents the maximum moving speed of the magnetorheological machining module A33. Measure the vertical distance from the measurement position of the machine vision device 3 to the working point of the polishing wheel 4 , and based on the vertical distance and the set number of revolutions per second n of the polishing wheel 4, calculate the time required for the working point of the polishing wheel 4 : ; Among them, represents the radius of the polishing wheel 4; A34. Calculate the minimum moving time between two adjacent machining positions of the robot 1 at the maximum moving speed : : ; Among them, represents the distance between two adjacent machining positions; A35. Calculate whether the condition holds: If the condition holds, there is no need to adjust the machine vision device 3 and the polishing wheel 4; if the condition does not hold, it is necessary to adjust the data sampling frequency of the machine vision device 3 and the number of revolutions per second n of the polishing wheel 4 to make the condition hold; A36. Perform mean filtering processing on the measurement data between every two adjacent machining positions and then output it. At the same time, the number of data for mean filtering needs to satisfy .

[0035] A4: Combine the second variable range, the maximum polishing gap, and the maximum ribbon thickness to process the optical element 6 to be processed. During the processing, the real-time control module adjusts the pose of the robot 1 in real time, and uses the change amount of the polishing gap generated after the adjustment as the input for processing the next machining position, so that the ribbon thickness at the next machining position is within the second variable range. The adjustment process is as follows: Control the polishing wheel 4 to move to the current machining position When, compare the current ribbon thickness measured by the machine vision device 3 with the second variable range : If the current ribbon thickness is within the second variable range , that is , there is no need to adjust the current pose of the robot 1; If the current ribbon thickness is not within the second variable range , that is , it is necessary to adjust the current pose of the robot 1: If the change amount of the current ribbon thickness is greater than or equal to the maximum ribbon thickness change amount , that is , adjust the pose of the robot 1 according to the following formula: ; Among them, represents the position where the free end of the robot 1 drives the magnetorheological processing module at the current processing position; represents the position where the free end of the robot 1 drives the magnetorheological processing module at the previous processing position; If the change amount of the current ribbon thickness is less than the maximum ribbon thickness change amount , that is , adjust the current polishing gap according to the following formula:

[0036] Among them, represents the polishing gap at the current processing position, represents the set initial polishing gap.

[0037] Specific Embodiment 2: The magnetorheological polishing method based on the polishing wheel position control provided in this specific embodiment, according to the magnetorheological polishing equipment for adjusting the processing posture based on machine vision in the embodiment of the present invention, combined with Figures 1 to 4 , includes the following steps: B1: Control the polishing wheel 4 to process the test optical element 7 with different polishing gaps, and obtain the second conversion relationship in the conversion relationship module. Step B1 includes the following steps: B11: Control the polishing wheel 4 to process the test optical element 7 with different polishing gaps, calculate the volume removal rate of the removal function at each processing position, and at the same time, the machine vision device 3 measures the ribbon thickness at each processing position in real time, and obtain in the conversion relationship module: ; Among them, represents the volume removal rate of the removal function and the ribbon thickness between; in this specific embodiment, specifically, control the polishing wheel 4 to perform fixed-point processing on the test optical element 7 for a period of time with different polishing gaps; B12: Under different polishing gaps, separately change the polishing wheel position, and process on the test optical element 7 to obtain the volume removal rate of the removal function at each processing position, and then obtain in the conversion relationship module: ; in, Indicates the polishing wheel position Between the removal function volume removal rate In this specific embodiment, specifically for controlling the polishing wheel 4 at different polishing gaps, individually changing the polishing wheel position, performing fixed-point processing on the test optical element 7 for a period of time; B13: According to the third conversion relationship and the fourth conversion relationship, the following formula is obtained: ; in, Indicates the second conversion relationship.

[0038] B2: Set the third variable range of the polishing wheel position , and according to the second conversion relationship Get the fourth variable range corresponding to the ribbon thickness ,Right now: ; ; Setting the maximum polishing wheel position , and according to the second conversion relationship Get the corresponding maximum ribbon thickness ,Right now: .

[0039] The third variable range and maximum polishing wheel position The configuration is adaptive according to the actual situation and is not limited in this embodiment.

[0040] B3: The control time calculation module adjusts the machine vision device 3 and the magnetorheological processing module in combination with the maximum polishing wheel position. Step B3 includes the following steps: Step B3 includes the following steps: B31. Count b data points measured by machine vision device 3 within a second and obtain the time it takes for machine vision device 3 to measure a point. ; ; B32. Calculate the maximum adjustment amount of the polishing wheel position The time required to control the magnetorheological processing module : ; in, Indicates the maximum moving speed of robot 1; B33, measure the vertical distance between the measuring position of the machine vision device 3 and the working point of the polishing wheel 4 , according to the vertical distance And the time required to calculate the working point of the polishing wheel 4 based on the set number of revolutions per second n of the polishing wheel 4 : ; in, Indicates the radius of the polishing wheel 4; B34. Calculate the maximum speed of robot 1 Minimum moving time between two adjacent processing positions : ; in, Indicates the distance between two adjacent processing positions; B35. Calculation conditions Is it true: If the condition is true, then there is no need to adjust the machine vision device 3 and the polishing wheel 4; if the condition is not true, then it is necessary to adjust the data sampling frequency of the machine vision device 3 and the number of revolutions per second n of the polishing wheel 4 to make the condition true; B36, perform mean filtering on the measurement data between each two adjacent processing positions before outputting them, and the number of mean filtered data Needs to be satisfied .

[0041] B4: Combine the third variable range, the maximum polishing wheel position and the maximum ribbon thickness to process the optical element to be processed, and during the processing, the real-time control module adjusts the polishing wheel position in real time. Specifically including: Control the polishing wheel to move to the current processing position The current ribbon thickness measured by the machine vision device With the fourth variable range Compare: If the current ribbon thickness In the fourth variable range Within, that is , then there is no need to adjust the current polishing wheel position Make adjustments; If the current ribbon thickness Not in the fourth variable range Within, that is , you need to check the current polishing wheel position Make adjustments: If the current ribbon thickness Greater than or equal to the maximum ribbon thickness ,Right now , the current polishing wheel position Adjust to the maximum polishing wheel position ; If the current ribbon thickness Less than the maximum ribbon thickness ,Right now , according to the following formula to calculate the current polishing wheel position Make adjustments: .

[0042] All transformation relationships in the above specific embodiments are obtained through fitting. The fitting process includes but is not limited to importing discrete data into Matlab software, using Matlab's polyfit fitting command to complete data fitting, and solving the respective transformation relationships. Polyfit fitting command is a basic general command of Matlab software. This method can more intuitively see the corresponding relationship between correlations and the corresponding function curve.

[0043] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0044] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A magnetorheological polishing device for adjusting the machining posture based on machine vision, characterized in that: It includes a robot, a control unit, a magnetorheological processing module, and a machine vision device; wherein: the magnetorheological processing module is arranged at the free end of the robot; the robot drives the polishing wheel in the magnetorheological processing module to process an optical element with magnetorheological fluid as the medium, and during the processing, the machine vision device measures the ribbon thickness of the magnetorheological fluid; The interior of the control unit includes: A time calculation module that calculates the measurement time of the machine vision device and the adjustment time of the magnetorheological processing module, and adjusts the machine vision device and the magnetorheological processing module according to the measurement time and the adjustment time; A conversion relationship module that obtains a first conversion relationship according to the ribbon thickness and the polishing gap of the polishing wheel, and obtains a second conversion relationship according to the ribbon thickness and the position of the polishing wheel of the polishing wheel; A machining program module that obtains a machining program according to the removal function obtained by the magnetorheological processing module and imports the machining program into the magnetorheological processing module; A real-time regulation module that adjusts the pose of the robot according to the first conversion relationship, or adjusts the position of the polishing wheel according to the second conversion relationship to keep the removal function stable during the processing of the optical element.

2. The magnetorheological polishing equipment for adjusting the machining posture based on machine vision according to claim 1, wherein: The magnetorheological processing module further includes a transmission belt, a polishing motor, a nozzle, a supply system, a magnet, a real-time adjustment device, and a magnetorheological mounting bracket; wherein, The magnetorheological mounting bracket is arranged on the free end; the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting bracket, and the real-time adjustment device adjusts the position of the polishing wheel; The polishing motor is arranged on the magnetorheological mounting bracket and is connected to the polishing wheel through the transmission belt, so that the polishing motor controls the polishing wheel to rotate, and further the polishing wheel processes the optical element; The nozzle is arranged on the magnetorheological mounting bracket along the rotation direction of the polishing wheel, and the supply system conveys magnetorheological fluid to the nozzle; The magnet is arranged on the magnetorheological mounting bracket and is close to the working point of the polishing wheel, so that the magnetorheological fluid changes the stiffness of the magnetorheological fluid under the influence of the magnetic field strength of the magnet.

3. The magnetorheological polishing equipment for adjusting the machining posture based on machine vision according to claim 2, wherein: The real-time adjustment device includes a displacement output motor, a lead screw, and a support fixing bracket; wherein, the support fixing bracket is arranged on the magnetorheological mounting bracket, the displacement output motor is arranged on the support fixing bracket, and the displacement output motor is connected to the lead screw arranged on the support fixing bracket; the polishing wheel is connected to the nut on the lead screw, so that the lead screw drives the polishing wheel to move; the control unit sends a control signal to the displacement output motor, and when the displacement output motor rotates the lead screw, the lead screw drives the polishing wheel to move.

4. The magnetorheological polishing equipment for adjusting the machining posture based on machine vision according to claim 3, wherein: The machine vision device, the robot, and the displacement output motor are respectively connected to the control unit to form their respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

5. A magnetorheological polishing method based on robot pose control, based on the magnetorheological polishing equipment for adjusting the machining pose based on machine vision according to any one of claims 1 to 4, characterized in that, It includes the following steps: A1: Control the pose of the robot, drive the polishing wheel to process the test optical element with different polishing gaps, and obtain the first conversion relationship in the conversion relationship module; A2: Set the first variable range of the polishing gap, and obtain the corresponding second variable range of the ribbon thickness according to the first conversion relationship; Set the maximum polishing gap, and obtain the corresponding maximum ribbon thickness according to the first conversion relationship; A3: Control the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum polishing gap; A4: Combine the second variable range, the maximum polishing gap and the maximum ribbon thickness to process the optical element to be processed. During the processing, the real-time regulation module adjusts the pose of the robot in real time, and uses the change amount of the polishing gap generated after the adjustment as the input when processing the next processing position, so that the ribbon thickness at the next processing position is within the second variable range.

6. The magnetorheological polishing method based on robot pose control according to claim 5, characterized in that: In step A1, control the polishing wheel to process the test optical element with different polishing gaps, measure the ribbon thickness in real time through the machine vision device, and obtain in the conversion relationship module: ； Among them, represents the polishing gap, represents the ribbon thickness, represents the first conversion relationship.

7. The magnetorheological polishing method based on robot pose control according to claim 6, characterized in that: In step A4, control the polishing wheel to move to the current machining position At this time, compare the currently measured ribbon thickness by the machine vision device with the second variable range and make a comparison: If the current ribbon thickness is within the second variable range then there is no need to adjust the current pose of the robot; If the current ribbon thickness is not within the second variable range then the current pose of the robot needs to be adjusted: If the change amount of the current ribbon thickness is greater than or equal to the maximum ribbon thickness change amount , where represents the initial ribbon thickness represents the maximum ribbon thickness, adjust the pose of the robot according to the following formula: ； Among them, represents the position of the free end at the current machining position; represents the position of the free end at the previous machining position, represents the maximum polishing gap, represents the initial polishing gap; If the change amount of the current ribbon thickness is less than the maximum ribbon thickness change amount , the current polishing gap is adjusted according to the following formula: ； Among them, represents the polishing gap at the current machining position.

8. A magnetorheological polishing method based on the position control of a polishing wheel, which is based on the magnetorheological polishing equipment for adjusting the machining posture based on machine vision according to any one of claims 1 to 4, characterized in that, The method includes the following steps: B1: Control the polishing wheel to process the test optical element with different polishing gaps, and obtain the second conversion relationship in the conversion relationship module; B2: Set the third variable range of the polishing wheel position, and obtain the corresponding fourth variable range of the ribbon thickness according to the second conversion relationship; Set the maximum polishing wheel position, and obtain the corresponding maximum ribbon thickness according to the second conversion relationship; B3: Control the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum polishing wheel position; B4: Combine the third variable range, the maximum polishing wheel position and the maximum ribbon thickness to process the optical element to be processed. During the processing, the real-time regulation module adjusts the polishing wheel position in real time.

9. The magnetorheological polishing method based on the polishing wheel position control according to claim 8, wherein: Step B1 includes the following steps: B11: Control the polishing wheel to process the test optical element with different polishing gaps, calculate the volume removal rate of the removal function at each processing position, and at the same time, the machine vision device measures the ribbon thickness of each processing position in real time, and obtain in the conversion relationship module: ； Among them, represents the third conversion relationship between the volume removal rate of the removal function and the ribbon thickness ; B12: Under different polishing gaps, separately change the polishing wheel position and process on the test optical element to obtain the volume removal rate of the removal function at each processing position, and then obtain in the conversion relationship module: ； Among them, represents the position of the polishing wheel and the volume removal rate of the removal function has a fourth conversion relationship; B13: According to the third conversion relationship and the fourth conversion relationship, obtain through the following formula: ； Among them, represents the second conversion relationship.

10. The magnetorheological polishing method based on the position control of the polishing wheel according to claim 9, wherein: In step B4, control the polishing wheel to move to the current machining position When the current ribbon thickness measured by the machine vision device is compared with the fourth variable range as follows: If the current ribbon thickness is within the fourth variable range , there is no need to adjust the current position of the polishing wheel ; If the current ribbon thickness is not within the fourth variable range then the current polishing wheel position needs to be adjusted: If the current ribbon thickness is greater than or equal to the maximum ribbon thickness , adjust the current polishing wheel position to the maximum polishing wheel position ; If the current ribbon thickness is less than the maximum ribbon thickness , the position of the current polishing wheel is adjusted according to the following formula: 。

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