Magnetorheological polishing equipment and method based on force sensor adjustment

Abstract

The invention relates to the technical field of optical machining, in particular to magnetorheological polishing equipment and method based on force sensor adjustment, and the equipment comprises a robot, a control unit, a magnetorheological machining module and a force sensor; wherein the magneto-rheological machining module is arranged at the tail end of the robot, and the force sensor is arranged between the magneto-rheological machining module and the robot; the robot drives the magneto-rheological machining module to machine the optical element, and the force sensor measures the machining force applied to the optical element by the magneto-rheological machining module in the machining process; according to the method, the real-time change of force in the magneto-rheological machining process is measured through a force sensor, a supply system, a nozzle and an actuator set in the magneto-rheological 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 polishing device and method based on force sensor adjustment. Background Art

[0002] Magnetorheological Finishing (MRF) is an advanced optical manufacturing technology developed in recent years, which has many advantages such as a stable removal function, controllable edge effect, small subsurface damage layer, no replication 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 processing mainly integrates the magnetorheological polishing module on a numerically controlled machine tool. However, the numerically controlled machine tool has some deficiencies (such as low degrees of freedom, large floor area, high cost, etc.), which lead to limitations on the deviation of aspheric surfaces and difficulties in precise pose control along the surface normal. In view of these deficiencies of the numerically controlled machine tool, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. The six-degree-of-freedom industrial robot has the advantages of high degrees of freedom, small floor area, large processing range, low cost, etc., making up for the deficiencies of the numerically controlled machine tool. Therefore, when the magnetorheological polishing module is integrated into the industrial robot, high-precision processing of large-aperture complex surface optical elements can be theoretically achieved. However, after combining the industrial robot with the magnetorheological polishing module, there are factors such as processing, assembly, load, trajectory planning, and reduction ratio, resulting in a relatively low accuracy of the robot end effector, which causes a large change in the polishing gap during the processing. At the same time, the magnetorheological polishing technology is an optical processing technology with a high degree of certainty of the removal function, and has high requirements for the change of the polishing gap during the polishing process. Generally, the change of the polishing gap in a magnetorheological numerical control processing center is within dozens of micrometers (PV < 0.1 mm), while the trajectory accuracy of common commercial robots is generally in the sub-millimeter to millimeter range, which leads to a large change in the polishing gap during the processing. The large change in the polishing gap will reduce the certainty of the removal function, thereby affecting the final processing accuracy. Therefore, the motion accuracy of current commercial large six-degree-of-freedom industrial robots often fails to meet the requirements of the magnetorheological polishing technology for the change of the removal function during high-precision polishing.

[0003] In view of the problem of low robot motion accuracy, the current real-time control scheme based on constant-force grinding and polishing has become a research hotspot, and the force-position control method has become a common robot constant-force regulation grinding and polishing control method. A common application method is to place a force sensor between the processing tool and the robot, calculate the pose error by measuring the change of force, and then compensate the robot pose error by means of the robot body or other motion compensation mechanisms to achieve constant-force control. Summary of the Invention

[0004] In view of this, the present invention aims to provide a magnetorheological polishing device and method based on force sensor adjustment. By measuring the real-time change of the force during magnetorheological processing with a force sensor, the supply system, nozzle, and actuator in the magnetorheological processing module are regulated in real time, thereby realizing the real-time constant control of the removal function.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows: A magnetorheological polishing device based on force sensor adjustment includes a robot, a control unit, an actuator group, a magnetorheological processing module, and a force sensor. Among them, the actuator group is connected to the end of the robot through the force sensor. The magnetorheological processing module is arranged at the output end of the actuator group, so that the robot and the actuator group drive the magnetorheological processing module to process the optical element, and during the processing, the force sensor measures the force applied by the polishing wheel in the magnetorheological processing module to the optical element. The interior of the control unit includes: A conversion relationship module, which obtains a first conversion relationship according to the force value collected by the force sensor and the first position of the supply system in the magnetorheological processing module, and obtains a second conversion relationship according to the force value and the second position of the nozzle in the magnetorheological processing module. A processing program module, which obtains a processing program according to the removal function generated when the magnetorheological processing module processes the optical element, and imports the processing program into the magnetorheological processing module. A real-time regulation module, which adjusts the actuator group, or adjusts the first position according to the first conversion relationship, or adjusts the second position according to the second conversion relationship, or combines the processing program to adjust the removal function during the processing, so that the removal function is stable during the process of processing the optical element.

[0006] Furthermore, the magnetorheological processing module further includes a transmission belt, a polishing motor, a magnet, and a magnetorheological mounting bracket. Among them, the magnetorheological mounting bracket is arranged at the output end of the actuator group, and the polishing wheel is arranged on the magnetorheological mounting bracket. 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. The nozzle is installed on the magnetorheological mounting bracket along the rotation direction of the polishing wheel through a nozzle mounting seat, and the nozzle mounting seat adjusts the installation angle of the nozzle, thereby changing the second position. The supply system conveys magnetorheological fluid to the nozzle. The magnet is arranged on the magnetorheological mounting bracket and near the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field intensity of the magnet to change the stiffness of the magnetorheological fluid, thereby processing the optical element.

[0007] Further, the supply system includes a liquid pump, a supply mounting bracket, a supply motor, and a lead screw. Among them, the supply motor and the lead screw are arranged on the supply mounting bracket, so that the supply motor drives the lead screw to rotate. The liquid pump is arranged on the nut of the lead screw, so that the lead screw drives the liquid pump to move along the lead screw, thereby changing the first position. The liquid pump transports the magnetorheological fluid to the nozzle through a pipeline.

[0008] Further, the nozzle mounting seat includes a fixing frame, a nozzle adjustment motor, a push rod, and a nozzle support frame. Among them, the fixing frame is arranged on the magnetorheological mounting frame, and arc-shaped slide rails are arranged on the inner side wall of the fixing frame. The nozzle adjustment motor is arranged on the magnetorheological mounting frame. One end of the push rod passes through the fixing frame and is connected to the nozzle adjustment motor, so that the nozzle adjustment motor pushes the slider on the arc-shaped slide rail through the push rod. One end of the nozzle support frame is arranged on the slider, and the nozzle is connected to the other end of the nozzle support frame, so that the nozzle adjustment motor pushes the slider through the push rod, and then the nozzle support frame drives the nozzle to move, thereby completing the adjustment of the second position.

[0009] Further, the force sensor, the robot, the actuator group, the nozzle adjustment motor, and the supply 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.

[0010] A magnetorheological polishing method for adjusting the position of a supply system, based on the magnetorheological polishing equipment for adjustment based on a force sensor provided by the present invention, includes the following steps: A1: Control the polishing wheel to process the test optical element with different polishing gaps, and record the change of force at each processing point through the force sensor, and obtain the third conversion relationship between the force and the polishing gap in the conversion relationship module; A2: Change the first position, control the polishing wheel to process at different positions of the test optical element with different polishing gaps, keep the force unchanged during the processing, and obtain the fourth conversion relationship between the polishing gap and the first position in the conversion relationship module; A3: In the conversion relationship module, calculate and obtain the first conversion relationship according to the third conversion relationship and the fourth conversion relationship; A4: Set a force change threshold and a maximum first position; combine the first conversion relationship, the force change threshold, and the maximum first position, control the magnetorheological processing module to process the optical element to be processed, and during the processing, the real-time regulation module adjusts the first position in real time.

[0011] Further, in step A4, control the magnetorheological processing module to move to the current processing position when comparing the current force measured by the force sensor with the force change threshold : If the current force Less than the force change threshold , do not adjust the current first position ; If the current force is greater than or equal to the force change threshold , adjust the current first position : If the current first position is less than the maximum first position , adjust the current first position according to the following formula:

[0012] wherein, represents the first conversion relationship; If the current first position is greater than or equal to the maximum first position , adjust the current first position to the maximum first position .

[0013] A magnetorheological polishing method for nozzle adjustment, based on the magnetorheological polishing equipment adjusted by a force sensor provided by the present invention, includes the following steps: B1: Control the polishing wheel to process the test optical element with different polishing gaps, record the force changes at each processing point through the force sensor, and obtain the fifth conversion relationship between the force and the polishing gap in the conversion relationship module; B2: Keep the force unchanged, at different polishing gaps, separately change the second position, and process at different positions of the test optical element, and obtain the sixth conversion relationship between the polishing gap and the second position in the conversion relationship module; B3: In the conversion relationship module, calculate the second conversion relationship according to the fifth conversion relationship and the sixth conversion relationship; B4: Set the force change threshold and the maximum second position; combine the second conversion relationship, the force change threshold and the maximum second position, control the magnetorheological processing module to process the optical element to be processed, and during the processing, the real-time regulation module adjusts the second position in real time.

[0014] Further, in step B4, when controlling the magnetorheological processing module to move to the current processing position , compare the current force measured by the force sensor with the force change threshold : If the current force is less than the force change threshold , do not adjust the current second position ; If the current force Greater than or equal to the force change threshold , adjust the current second position as follows: If the current second position is less than the maximum second position , the current second position is adjusted according to the following formula:

[0015] wherein, represents the second conversion relationship; If the current second position is greater than or equal to the maximum second position , the current second position is adjusted to the maximum second position .

[0016] A magnetorheological polishing method with a variable removal function, based on the magnetorheological polishing equipment regulated by a force sensor provided by the present invention, includes the following steps: C1: Control the polishing wheel to process the test optical element with different polishing gaps to obtain the removal function; meanwhile, record the force change at each processing point through the force sensor during the processing, and obtain the seventh conversion relationship between the volume removal rate of the removal function and the force at each processing point in the conversion relationship module; C2: Use the machining program module to obtain the machining program according to the removal function, and import the machining program into the magnetorheological machining module; C3: Set the force change threshold and the maximum force; combine the seventh conversion relationship, the force change threshold and the maximum force, control the magnetorheological machining module to process the optical element to be machined, and calculate the removal function of each processing point during the processing to obtain a variable removal function set, and then generate a new machining program; C4: Import the new machining program into the magnetorheological machining module, and then perform secondary machining on the optical element to be machined.

[0017] Further, obtaining the seventh conversion relationship in step C1 includes the following steps: C11: Control the polishing wheel to process the test optical element with different polishing gaps, and record the corresponding force change at each processing point through the force sensor, and obtain in the conversion relationship module:

[0018] wherein, represents the force and the polishing gap between the eighth conversion relationship; C12: Control the polishing wheel to process at different positions of the test optical element with different polishing gaps, and calculate the volume removal rate of the removal function at each processing point. In the conversion relationship module, obtain:

[0019] where, represents the volume removal rate of the removal function and the ninth conversion relationship between the polishing gap ; C13: In the conversion relationship module, calculate the seventh conversion relationship according to the eighth conversion relationship and the ninth conversion relationship, that is:

[0020] where, represents the seventh conversion relationship.

[0021] Further, in step C3, when controlling the magnetorheological processing module to move to the current processing position , compare the current force measured by the force sensor with the force change threshold : If the current force is less than the force change threshold , do not calculate the change of the current removal function; If the current force is greater than or equal to the force change threshold , calculate the change of the current removal function: If the current force is less than the force maximum , calculate the removal function corresponding to the current processing point , and then obtain the variable removal function set :

[0022] where, represents the volume removal rate of the removal function corresponding to the current processing point ; If the current force is greater than or equal to the force maximum , obtain the removal function corresponding to the current processing point , and then obtain the variable removal function set :

[0023] where, represents the force maximum The corresponding maximum removal function volume removal rate.

[0024] An actuator-adjusted magnetorheological polishing method, based on the magnetorheological polishing equipment adjusted based on a force sensor provided by the present invention, includes the following steps: D1: Set the force change threshold and the maximum value regulation of the actuator group; D2: Control the magnetorheological processing module to move to the current processing position When, compare the current force measured by the force sensor with the force change threshold: If the current force is less than the force change threshold, execute step D4; if the current force is greater than the force change threshold, execute step D3; D3: If the current position change of the polishing wheel is less than the maximum value regulation, control the output displacement of the actuator group to be the current position change, and process the optical element to be processed; if the current position change of the polishing wheel is greater than the maximum value regulation, control the output displacement of the actuator group to be the maximum value regulation, and process the optical element to be processed; D4: Control the magnetorheological processing module to move to the next processing position, and repeat steps D2 and D3 until the magnetorheological processing module traverses all the processing points on the optical element to be processed.

[0025] Compared with the prior art, the present invention can achieve the following beneficial effects: In the magnetorheological polishing equipment and method adjusted based on a force sensor according to the present invention, the force applied by the magnetorheological processing module to the optical element during six-dimensional processing driven by the robot is measured in real time by the force sensor, so as to perform real-time regulation on the supply system, nozzle and actuator group in the magnetorheological processing module, and then realize real-time constant control of the change of the removal function under multi-factor coupling during the processing of the optical element; at the same time, the acquisition of the pose information does not need to rely on the actual processing process, and the pose error information of the processing equipment can be obtained during the processing trial operation link (no magnetorheological fluid is introduced in this link and no processing effect is generated), and it is not necessary to place the measuring equipment at the lowest point of the polishing wheel, which will not affect the actual processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings forming 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 is a schematic structural diagram of the magnetorheological polishing equipment adjusted based on a force sensor according to an embodiment of the present invention from one perspective; Figure 2 is a schematic structural diagram of the magnetorheological polishing equipment adjusted based on a force sensor according to an embodiment of the present invention from another perspective; Figure 3 Structural schematic diagram of the actuator according to the embodiment of the present invention Figure 4 Structural schematic diagram of the supply system according to the embodiment of the present invention Figure 5 Structural schematic diagram of the liquid pump according to the embodiment of the present invention Figure 6 Structural schematic diagram of the nozzle mounting seat according to the embodiment of the present invention

[0027] Explanation of reference numerals in the drawings: 1. Robot; 2. Control unit; 3. Force sensor; 4. High-frequency actuator; 5. Test bench; 6. Optical element to be processed; 7. Test optical element; 8. Supply system; 9. Nozzle; 10. Polishing wheel; 11. Transmission belt; 12. Polishing motor; 13. Magnet; 14. Magnetorheological mounting bracket; 15. Nozzle mounting seat; 16. Liquid pump; 17. Supply mounting bracket; 18. Supply motor; 19. Lead screw; 20. Mounting fixing plate; 21. Slide rail; 22. Liquid pump body; 23. Cooling chamber; 24. Magnetorheological fluid storage chamber; 25. Cooling water inlet; 26. Magnetorheological fluid inlet; 27. Cooling water outlet; 28. Magnetorheological fluid outlet; 29. Nozzle support frame; 30. Nozzle adjustment motor; 31. Fixed frame; 32. Push rod; 33. Slide block; 34. Arc slide rail; 35. Transition plate; 36. Cylinder block; 37. Chamber A; 38. Chamber B; 39. Oil scraping ring; 40. Connecting plate; 41. Moving piston. Detailed implementation manners

[0028] 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 accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0029] 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.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. These terms are only used 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 construed 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.

[0031] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should 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.

[0032] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0033] As Figure 1 and Figure 2 shown, the magnetorheological finishing equipment based on force sensor adjustment described in the embodiment of the present invention includes a robot 1, a control unit 2, a magnetorheological processing module, a force sensor 3, and an actuator group. The actuator group is arranged at the end of the robot 1, and the force sensor 3 is arranged on the actuator group and the robot 1; the magnetorheological processing module is mounted on the output end of the actuator group, so that the robot 1 and the actuator group drive the magnetorheological processing module to process the optical element 6 to be processed or the test optical element 7 placed on the experimental table 5, and during the processing, the force sensor 3 measures the force applied by the polishing wheel 10 in the magnetorheological processing module to the optical element 6 to be processed or the test optical element 7. In the embodiment of the present invention, it is preferably to arrange the force sensor 3 between the actuator group and the robot 1, which simplifies the mechanical structure while reducing the weight of the magnetorheological processing module; in addition, by arranging the magnetorheological processing module and the robot 1 on both sides of the force sensor 3, the force balance of the force sensor 3 is ensured, the service life of the force sensor 3 is extended, thereby reducing the complexity and cost of the equipment, while improving the assembly accuracy of the equipment and the final movement accuracy of the equipment.

[0034] In the embodiment of the present invention, the actuator group is composed of two cascaded high-frequency actuators 4, that is, one high-frequency actuator 4 is installed on the output end of the other high-frequency actuator 4, so that the total output displacement of the actuator group is the sum of the output displacements of the two high-frequency actuators 4. In the embodiment of the present invention, the high-frequency actuator 4 preferably adopts the SG model hydrostatic linear cylinder of Jilin Huakong Test Instrument Co., Ltd., and the structure of each high-frequency actuator 4 is as Figure 3 shown, including a transition plate 35, a cylinder block 36, an A chamber 37, a B chamber 38, an oil scraping ring 39, a connecting plate 40 and a moving piston 41. The transition plate 35 is used to connect the end flange of the robot 1 with the cylinder block 36 of the high-frequency actuator 4. The A chamber 37 and the B chamber 38 are used to control the inflow and outflow of hydraulic oil. The oil scraping ring 39 is used to prevent the hydraulic oil from flowing out of the cylinder block 36. The moving piston 41 is used for position output. The connecting plate 40 is used to connect the moving piston 41 with the magnetorheological processing module or another high-frequency actuator 4, so as to output displacement to the magnetorheological processing module or another high-frequency actuator 4.

[0035] The interior of the control unit 2 includes a conversion relationship module, a machining program module and a real-time regulation module. Among them, the conversion relationship module obtains a first conversion relationship according to the force value collected by the force sensor 3 and the first position of the supply system 8 in the magnetorheological processing module, and obtains a second conversion relationship according to the force value and the second position of the nozzle 9 in the magnetorheological processing module. In the embodiment of the present invention, it is stipulated that the first position of the supply system 8 is the vertical distance between the nozzle orifice of the nozzle 9 and the working point of the supply system 8 (that is, the liquid outlet of the supply system 8). When the vertical distance between the nozzle orifice of the nozzle 9 and the working point of the supply system 8 changes, the flow rate will change, and then the removal function will change. It is stipulated that the second position of the nozzle 9 is the vertical distance between the nozzle orifice of the nozzle 9 and the working point of the polishing wheel 10 (that is, along the normal direction of the surface of the optical element 6 to be processed or the test optical element 7, the closest point between the polishing wheel 10 and the surface of the optical element 6 to be processed or the test optical element 7). The machining program module is used to obtain a machining program according to the removal function generated when the magnetorheological processing module processes the optical element 6 to be processed or the test optical element 7, and import the machining program into the magnetorheological processing module. The real-time regulation module is used to adjust the actuator group, or adjust the first position according to the first conversion relationship, or adjust the second position according to the second conversion relationship, or adjust the removal function during the machining process in combination with the machining program, so as to stabilize the removal function during the process of machining the optical element.

[0036] In the embodiment of the present invention, the structure of the supply system 8 is as Figure 1 , Figure 2 and Figure 4As shown, it includes a liquid pump 16, a supply mounting bracket 17, a supply motor 18, and a lead screw 19. The lead screw 19 and the nut with balls thereon form a ball screw. Among them, the supply motor 18 and the lead screw 19 are installed on the supply mounting bracket 17, and the output end of the supply motor 18 is connected to one end of the lead screw 19, so that the supply motor 18 drives the lead screw 19 to rotate. The liquid pump 16 is installed on the moving block of the lead screw 19, so that the lead screw 19 drives the liquid pump 16 to move, thereby changing the first position. Specifically, a nut adapted to the lead screw 19 is provided on the lead screw 19, and there are balls in the nut. The lead screw 19 and the nut together form a ball screw. The moving block is fixed on the nut. At this time, when the lead screw 19 rotates, the cooperation between the lead screw 19 and the nut drives the moving block to move along the lead screw 19, and further realizes the lead screw 19 driving the liquid pump 16 to move. The liquid pump 16 conveys the magnetorheological fluid to the nozzle 9 through a pipeline. In the embodiment of the present invention, in order to enable the liquid pump 16 to move smoothly along the direction of the lead screw 19 without deviation, a slide rail 21 parallel to the lead screw 19 is installed on each side of the lead screw 19, and the liquid pump 16 is fixedly connected to the moving block of the lead screw 19 and the sliders on the two slide rails 21 through a mounting fixing plate 20, so that the supply motor 18 drives the lead screw 19, and the lead screw 19 cooperates with the two slide rails 21 to drive the mounting fixing plate 20 and the liquid pump 16 on the mounting fixing plate 20 to move smoothly.

[0037] In the embodiment of the present invention, the liquid pump body 22 of the liquid pump 16 selects the DFLD vertical multi-stage pump of Shanghai Orient Pump Industry Co., Ltd. The structure of the entire liquid pump 16 is as Figure 5 shown, including a liquid pump body 22, a cooling chamber 23, and a magnetorheological fluid storage chamber 24. The liquid pump body 22 is used to supply the magnetorheological fluid; the cooling chamber 23 is mainly used to store cooling water and cool down the magnetorheological fluid; the magnetorheological fluid storage chamber 24 is mainly used for storing the magnetorheological fluid. When the liquid pump 16 works, the cooling water enters the cooling chamber 23 from the cooling water inlet 25 to cool down the magnetorheological fluid. The magnetorheological fluid enters the liquid pump body 22 from the magnetorheological fluid inlet 26 through the magnetorheological fluid storage chamber 24; after the cooling water completes the cooling of the magnetorheological fluid in the liquid cooling chamber 23, it is discharged from the cooling water outlet 27; the cooled magnetorheological fluid is output from the magnetorheological fluid outlet 28 and conveys the magnetorheological fluid to the nozzle 9 through a pipeline. At this time, the liquid outlet of the supply system 8 is the magnetorheological fluid outlet 28. Further, the first position of the supply system 8 is the vertical distance between the nozzle orifice of the nozzle 9 and the magnetorheological fluid outlet 28.

[0038] The magnetorheological processing module further includes a conveyor belt 11, a polishing motor 12, a magnet 13, and a magnetorheological mounting bracket 14. The magnetorheological mounting bracket 14 is fixedly installed on the output end of the actuator group, and the polishing wheel 10 is arranged on the magnetorheological mounting bracket 14. The polishing motor 12 is installed on the magnetorheological mounting bracket 14, and the output end of the polishing motor 12 is connected to the bearing of the polishing wheel 10 through the conveyor belt 11, so that the polishing motor 12 controls the rotation of the polishing wheel 10. In the embodiment of the present invention, the manner in which the polishing motor 12 drives the polishing wheel 10 to rotate can refer to the invention patent application with the publication number of CN118322074A, the publication date of July 12, 2024, and the patent name of "Self-rotating Polishing Module Processing System". The nozzle 9 is installed on the magnetorheological mounting bracket 14 along the rotation direction of the polishing wheel 10 through the nozzle mounting seat 15, and the nozzle mounting seat 15 adjusts the mounting angle of the nozzle 9, thereby changing the second position of the nozzle orifice of the nozzle 9. The supply system 8 conveys the magnetorheological fluid to the nozzle 9 through a pipeline, and the nozzle 9 sprays the magnetorheological fluid to the working point of the polishing wheel 10, so that the polishing wheel 10 processes the optical element 6 to be processed or the test optical element 7 with the magnetorheological fluid as the medium. The magnet 13 is installed on the magnetorheological mounting bracket 14 and close to the working point of the polishing wheel 10, so that the magnetorheological fluid changes its stiffness under the influence of the magnetic field strength of the magnet 13.

[0039] The structure of the nozzle mounting seat 15 is as Figure 6 shown. Among them Figure 6 Figure (a) shows a schematic structural diagram when the nozzle 9 is installed on the nozzle mounting seat 15, Figure 6 and figure (b) shows a schematic structural diagram when the nozzle 9 is not installed on the nozzle mounting seat 15. In the nozzle mounting seat 15, the fixing frame 31 is an L-shaped structure and is fixed on the magnetorheological mounting bracket 14, and an arc slide rail 34 is arranged on the inner side wall of the fixing frame 31. The nozzle adjustment motor 30 is installed on the magnetorheological mounting bracket 14, and one end of the push rod 32 passes through the bottom edge of the fixing frame 31 and is connected to the output end of the nozzle adjustment motor 30, so that the nozzle adjustment motor 30 pushes the push rod 32, and then the push rod 32 pushes the slider 33 on the arc slide rail 34 to move along the arc slide rail 34. One end of the nozzle support frame 29 is fixed on the slider 33, and the nozzle 9 is installed at the other end of the nozzle support frame 29. When controlling the nozzle mounting seat 15 to adjust the position of the nozzle 9, the nozzle adjustment motor 30 outputs displacement, so that the push rod 32 pushes the slider 33, and then the nozzle support frame 29 drives the nozzle 9 to move, thereby completing the adjustment of the second position of the nozzle 9.

[0040] The robot 1, force sensor 3, supply system 8, actuator assembly, and nozzle mounting bracket 15 are each connected to the control unit 2 to form a communication circuit, enabling the control unit 2 to receive and send signals via the corresponding communication circuit. Specifically, the control unit 2 is in communication with the supply motor 18 via a circuit. During operation, the control unit 2 sends control instructions to the supply motor 18, which drives the lead screw 19 to rotate. The rotating lead screw 19 drives the mounting plate 20 up and down, thereby changing the vertical position of the liquid pump 16 and thus the first position of the supply system 8. The control unit 2 controls the hydraulic oil pressure in the high-frequency actuator 4, thereby controlling the extension and retraction of the moving piston 41 to achieve position control of the magnetorheological processing module, thereby changing the output of the actuator assembly. The control unit 2 controls the nozzle adjustment motor 30 to change the position of the nozzle support frame 29, which moves along the arc slide 34, thereby changing the second position of the nozzle 9. Because the polishing wheel 10 generates a strong magnetic field during polishing, the communication circuit avoids this strong magnetic field.

[0041] Based on the magnetorheological polishing equipment based on force sensor adjustment described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological polishing method based on force sensor adjustment, which includes a magnetorheological polishing method with supply system position adjustment, a magnetorheological polishing method with nozzle adjustment, a magnetorheological polishing method with variable removal function, and a magnetorheological polishing method with actuator adjustment.

[0042] Specific embodiment 1: The magnetorheological polishing method for adjusting the position of the supply system provided in this specific embodiment is based on the magnetorheological polishing device based on force sensor adjustment described in the embodiment of the invention, combined with Figure 1 、 Figure 2 and Figure 4 , including the following steps: A1: Control the polishing wheel 10 to process the test optical element 7 with different polishing gaps, and use the force sensor 3 to record the corresponding force changes at each processing point. The following is obtained in the conversion relationship module:

[0043] in, Expressive power Polishing gap In this specific embodiment, the polishing wheel 10 is controlled to perform fixed-point processing on the test optical element 7 at different polishing gaps for a period of time.

[0044] A2: Change the first position and control the polishing wheel 10 to process different positions of the test optical element 7 with different polishing gaps. Keep the force unchanged during the processing. In the conversion relationship module, obtain:

[0045] Among them, represents the polishing gap and the fourth conversion relationship with the first position . In this specific embodiment, specifically, the first position is changed to control the polishing wheel 10 to perform fixed-point machining for a period of time at different positions of the test optical element 7 with different polishing gaps.

[0046] A3: In the conversion relationship module, the first conversion relationship is calculated according to the third conversion relationship and the fourth conversion relationship, that is:

[0047] Among them, represents the first conversion relationship.

[0048] A4: Set the force change threshold and the maximum first position; combine the first conversion relationship, the force change threshold and the maximum first position to control the magnetorheological machining module to machine the optical element 6 to be machined, and during the machining process, the real-time regulation module makes real-time adjustments to the first position. The force change threshold and the maximum first position are adaptively set according to the actual situation, and this specific implementation does not limit this. The specific process of step A4 is as follows: Control the magnetorheological machining module to move to the current machining position When, compare the current force measured by the force sensor 3 with the force change threshold If the current force is less than the force change threshold , do not adjust the current first position ; If the current force is greater than or equal to the force change threshold , adjust the current first position : If the current first position is less than the maximum first position , adjust the current first position according to the following formula:

[0049] If the current first position is greater than or equal to the maximum first position , adjust the current first position to the maximum first position .

[0050] Specific Embodiment 2: The magnetorheological polishing method for nozzle adjustment provided in this specific embodiment, based on the magnetorheological polishing equipment adjusted based on a force sensor according to the embodiments of the present invention, in combination with Figure 1 and Figure 2 , and Figures 4 to 6 , includes the following steps: B1: Control the polishing wheel 10 to process the test optical element 7 with different polishing gaps, and record the change of force at each processing point through the force sensor 3, and obtain in the conversion relationship module:

[0051] wherein, represents the force and the fifth conversion relationship between the polishing gap . In this specific embodiment, specifically, control the polishing wheel 10 to perform fixed-point processing on the test optical element 7 for a certain period of time with different polishing gaps.

[0052] B2: Keep the force unchanged, at different polishing gaps, separately change the second position, and perform processing at different positions of the test optical element 7, and record the numerical changes of the polishing gap and the second position at the same time, and obtain in the conversion relationship module:

[0053] wherein, represents the sixth conversion relationship between the polishing gap and the second position . In this specific embodiment, specifically, keep the force unchanged, at different polishing gaps, separately change the second position, and perform fixed-point processing on the test optical element 7 for a certain period of time at different positions.

[0054] B3: In the conversion relationship module, calculate the second conversion relationship according to the fifth conversion relationship and the sixth conversion relationship, that is:

[0055] wherein, represents the second conversion relationship.

[0056] B4: Set a force change threshold and a maximum second position; combine the second conversion relationship, the force change threshold and the maximum second position, control the magnetorheological processing module to process the optical element 6 to be processed, and during the processing, the real-time regulation module adjusts the second position in real time. The force change threshold and the maximum second position are adaptively set according to the actual situation, and this specific implementation does not limit this. The specific process of step B4 is: Control the magnetorheological processing module to move to the current processing position When, for the current force measured by the force sensor 3 Compare with the force change threshold as follows: If the current force is less than the force change threshold , do not adjust the current second position ; If the current force is greater than or equal to the force change threshold , adjust the current second position as follows: If the current second position is less than the maximum second position , the current second position is adjusted according to the following formula:

[0057] If the current second position is greater than or equal to the maximum second position , adjust the current second position to the maximum second position .

[0058] Specific Embodiment 3: The magnetorheological polishing method with a variable removal function provided in this specific embodiment, according to the magnetorheological polishing equipment adjusted based on a force sensor described in the embodiments of the present invention, in combination with Figure 1 and Figure 2 , includes the following steps: C1: Control the polishing wheel 10 to process the test optical element 7 with different polishing gaps to obtain the removal function; at the same time, record the corresponding force changes at each processing point through the force sensor 3 during the processing, and obtain the seventh conversion relationship between the volume removal rate of the removal function and the force at each processing point in the conversion relationship module. Specifically, it includes the following steps: C11: Control the polishing wheel 10 to process the test optical element 7 with different polishing gaps, and record the corresponding force changes at each processing point through the force sensor 3, and obtain in the conversion relationship module:

[0059] wherein, represents the eighth conversion relationship between the force and the polishing gap . In this specific embodiment, specifically, control the polishing wheel 10 to perform fixed-point processing on the test optical element 7 for a certain period of time with different polishing gaps.

[0060] C12: Control the polishing wheel 10 to process at different positions of the test optical element 7 with different polishing gaps, and calculate the volume removal rate of the removal function at each processing point, and obtain in the conversion relationship module:

[0061] Among them, represents the removal function volume removal rate and the polishing gap The ninth conversion relationship therebetween. In this specific embodiment, specifically, the polishing wheel 10 is controlled to perform fixed-point machining for a certain period of time at different positions of the test optical element 7 with different polishing gaps.

[0062] C13: In the conversion relationship module, the seventh conversion relationship is calculated according to the eighth conversion relationship and the ninth conversion relationship, that is:

[0063] Among them, represents the seventh conversion relationship.

[0064] C2: The machining program is obtained according to the removal function by using the machining program module, and the machining program is imported into the magnetorheological machining module.

[0065] C3: Set the force change threshold, the maximum force, and the maximum polishing gap of the polishing wheel 10; combining the seventh conversion relationship, the force change threshold, and the maximum force, control the magnetorheological machining module to machine the optical element 6 to be machined, and during the machining process, calculate the removal function of each machining point to obtain a variable removal function set, and then generate a new machining program. The force change threshold, the maximum force, and the maximum polishing gap are adaptively set according to the actual situation, and this specific implementation does not limit this. The specific process of step C3 is as follows: Control the magnetorheological machining module to move to the current machining position When, the current force measured by the force sensor 3 is compared with the force change threshold : If the current force is less than the force change threshold , do not calculate the change of the current removal function; If the current force is greater than or equal to the force change threshold , calculate the change of the current removal function as follows: If the current force is less than the maximum force , calculate the removal function corresponding to the current machining point through the following formula, and then obtain a variable removal function set :

[0066] Among them, Indicates the current machining point The volume removal rate of the corresponding removal function; If the current force is greater than or equal to the maximum force , the current machining point is obtained through the following formula The corresponding removal function , and then the variable removal function set is obtained :

[0067] Among them, Indicates the maximum force The maximum volume removal rate of the corresponding removal function.

[0068] C4: Import the new machining program into the magnetorheological machining module, and then perform secondary machining on the optical element 6 to be machined.

[0069] Specific embodiment 4: The magnetorheological polishing method for actuator adjustment provided in this specific embodiment, according to the magnetorheological polishing equipment based on force sensor adjustment described in the embodiments of the present invention, combined with Figures 1 to 3 , includes the following steps: D1: Set the force change threshold and the maximum value regulation of the actuator group. The force change threshold and the maximum value regulation are adaptively set according to the actual situation, and this specific implementation does not limit this.

[0070] D2: When controlling the magnetorheological machining module to move to the current machining position , compare the current force measured by the force sensor 3 with the force change threshold : If the current force is less than the force change threshold , do not adjust the current position of the polishing wheel 10, and directly execute step D4; If the current force is greater than or equal to the force change threshold , execute step D3 to adjust the current position of the polishing wheel 10.

[0071] D3: Compare the current position change of the polishing wheel 10 with the maximum value regulation of the actuator group : If the current position change of the polishing wheel 10 is less than the maximum value regulation , control the output displacement of the actuator group to be the current position change , that is:

[0072] Among them, represents the sum of the output displacements of two cascaded high-frequency actuators, represents the output displacement of one of the cascaded high-frequency actuators, represents the output displacement of the other cascaded high-frequency actuator, and at this time the current polishing gap is:

[0073] wherein, represents the polishing gap when the polishing wheel 10 is at the previous machining position, and machined the optical element 6 to be machined; If the current position of the polishing wheel 10 changes is greater than or equal to the maximum value regulation , at this time the output displacement of the actuator group is the maximum value regulation , that is:

[0074] At this time the current polishing gap of the polishing wheel 10 is:

[0075] and machine the optical element 6 to be machined.

[0076] D4: Control the magnetorheological machining module to move to the next machining position, and repeat step D2 until the magnetorheological machining module traverses all the machining points on the optical element 6 to be machined.

[0077] The conversion relationships in the above specific embodiments are all obtained by fitting. The fitting process includes and is not limited to importing discrete data into Matlab software, and completing data fitting with the polyfit fitting instruction of Matlab software to solve their respective conversion relationships; The Polyfit fitting instruction is a basic general instruction of matlab software. In this way, the corresponding relationship and the corresponding function curve between relevant can be seen more intuitively.

[0078] It should be understood that various forms of the process shown above can be used, reordering, adding or deleting steps. For example, the steps recorded in the disclosure of the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.

[0079] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A magnetorheological polishing device based on force sensor adjustment, characterized in that: It includes a robot, a control unit, an actuator group, a magnetorheological machining module, and a force sensor; wherein, the actuator group is connected to the end of the robot through the force sensor; the magnetorheological machining module is arranged at the output end of the actuator group, so that the robot and the actuator group drive the magnetorheological machining module to process an optical element, and during the processing, the force sensor measures the force applied by the polishing wheel in the magnetorheological machining module to the optical element for processing; The interior of the control unit includes: A conversion relationship module, which obtains a first conversion relationship according to the force value collected by the force sensor and the first position of the supply system in the magnetorheological machining module, and obtains a second conversion relationship according to the force value and the second position of the nozzle in the magnetorheological machining module; A machining program module, which obtains a machining program according to the removal function generated when the magnetorheological machining module processes the optical element, and imports the machining program into the magnetorheological machining module; A real-time regulation module, which adjusts the actuator group, or adjusts the first position according to the first conversion relationship, or adjusts the second position according to the second conversion relationship, or combines the machining program to adjust the removal function during the machining process, so that the removal function is stable during the process of machining the optical element.

2. The magnetorheological polishing equipment adjusted based on a force sensor according to claim 1, wherein: The magnetorheological machining module further includes a transmission belt, a polishing motor, a magnet, and a magnetorheological mounting bracket; wherein, The magnetorheological mounting bracket is arranged at the output end of the actuator group, and the polishing wheel is arranged on the magnetorheological mounting bracket; 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; The nozzle is installed on the magnetorheological mounting bracket along the rotation direction of the polishing wheel through a nozzle mounting seat, and the nozzle mounting seat adjusts the installation angle of the nozzle, thereby changing the second position; the supply system conveys the magnetorheological fluid to the nozzle; The magnet is arranged on the magnetorheological mounting bracket and near the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field intensity of the magnet to change the stiffness of the magnetorheological fluid, thereby processing the optical element.

3. The magnetorheological polishing apparatus based on force sensor adjustment according to claim 2, wherein: The supply system includes a liquid pump, a supply mounting bracket, a supply motor, and a lead screw; wherein, the supply motor and the lead screw are arranged on the supply mounting bracket, so that the supply motor drives the lead screw to rotate; the liquid pump is arranged on the nut of the lead screw, so that the lead screw drives the liquid pump to move along the lead screw, thereby changing the first position; the liquid pump conveys the magnetorheological fluid to the nozzle through a pipeline.

4. The magnetorheological polishing device adjusted based on a force sensor according to claim 3, wherein: The nozzle mounting seat includes a fixing frame, a nozzle adjustment motor, a push rod, and a nozzle support frame. Among them, the fixing frame is arranged on the magnetorheological mounting frame, and arc-shaped slide rails are arranged on the inner side wall of the fixing frame. The nozzle adjustment motor is arranged on the magnetorheological mounting frame. One end of the push rod passes through the fixing frame and is connected to the nozzle adjustment motor, so that the nozzle adjustment motor drives the slider on the arc-shaped slide rail to move through the push rod. One end of the nozzle support frame is arranged on the slider, and the nozzle is connected to the other end of the nozzle support frame, so that the nozzle adjustment motor drives the slider through the push rod, and further drives the nozzle to move through the nozzle support frame, thereby completing the adjustment of the second position.

5. The magnetorheological polishing apparatus adjusted based on a force sensor according to claim 4, wherein: The force sensor, the robot, the actuator group, the nozzle adjustment motor, and the supply 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.

6. A magnetorheological polishing method for adjusting the position of a supply system, based on the magnetorheological polishing equipment adjusted based on a force sensor according to any one of claims 1 to 5, characterized in that: It includes the following steps: A1: Control the polishing wheel to process the test optical element with different polishing gaps, and record the change of force at each processing point through the force sensor, and obtain the third conversion relationship between the force and the polishing gap in the conversion relationship module. A2: Change the first position, control the polishing wheel to process at different positions of the test optical element with different polishing gaps, and keep the force unchanged during the processing, and obtain the fourth conversion relationship between the polishing gap and the first position in the conversion relationship module. A3: In the conversion relationship module, calculate and obtain the first conversion relationship according to the third conversion relationship and the fourth conversion relationship. A4: Set a force change threshold and a maximum first position; combine the first conversion relationship, the force change threshold, and the maximum first position, control the magnetorheological processing module to process the optical element to be processed, and during the processing, the real-time regulation module makes real-time adjustment to the first position.

7. The magnetorheological polishing method for adjusting the position of the supply system according to claim 6, characterized in that: In step A4, control the magnetorheological machining module to move to the current machining position When the current force measured by the force sensor is compared with the force change threshold as follows: If the current force is less than the force change threshold , do not adjust the current first position ; If the current force is greater than or equal to the force change threshold , adjust the current first position as follows: If the current first position is less than the maximum first position , adjust the current first position according to the following formula: Among them, represents the first conversion relationship; If the current first position is greater than or equal to the maximum first position , adjust the current first position to the maximum first position .

8. A nozzle-adjusted magnetorheological polishing method, based on the force sensor-adjusted magnetorheological polishing equipment according to any one of claims 1 to 5, characterized in that: It includes the following steps: B1: Control the polishing wheel to process the test optical element with different polishing gaps, and record the change of force at each processing point through the force sensor, and obtain the fifth conversion relationship between the force and the polishing gap in the conversion relationship module. B2: Keep the force unchanged, separately change the second position under different polishing gaps, and process at different positions of the test optical element, and obtain the sixth conversion relationship between the polishing gap and the second position in the conversion relationship module. B3: In the conversion relationship module, calculate and obtain the second conversion relationship according to the fifth conversion relationship and the sixth conversion relationship. B4: Set a force change threshold and a maximum second position; combine the second conversion relationship, the force change threshold, and the maximum second position, control the magnetorheological processing module to process the optical element to be processed, and during the processing, the real-time regulation module makes real-time adjustment to the second position.

9. The nozzle-adjusted magnetorheological polishing method according to claim 8, characterized in that: In step B4, control the magnetorheological machining module to move to the current machining position When doing so, compare the current force measured by the force sensor with the force change threshold as follows: If the current force is less than the force change threshold , the current second position is not adjusted; If the current force is greater than or equal to the force change threshold , adjust the current second position as follows: If the current second position is less than the maximum second position , the current second position is adjusted according to the following formula: Among them, represents the second conversion relationship; If the current second position is greater than or equal to the maximum second position , adjust the current second position to the maximum second position .

10. A magnetorheological polishing method with a variable removal function, based on the magnetorheological polishing equipment adjusted based on a force sensor according to any one of claims 1 to 5, characterized in that: It includes the following steps: C1: Control the polishing wheel to process the test optical element with different polishing gaps to obtain the removal function; meanwhile, record the force changes at each processing point through the force sensor during the processing, and obtain the seventh conversion relationship between the volume removal rate of the removal function at each processing point and the force in the conversion relationship module; C2: Use the processing program module to obtain the processing program according to the removal function, and import the processing program into the magnetorheological processing module; C3: Set the force change threshold and the maximum force value; combine the seventh conversion relationship, the force change threshold and the maximum force value to control the magnetorheological processing module to process the optical element to be processed. During the processing, calculate the removal function at each processing point to obtain a variable removal function set, and then generate a new processing program; C4: Import the new processing program into the magnetorheological processing module, and then perform secondary processing on the optical element to be processed.

11. The magnetorheological polishing method with a variable removal function according to claim 10, characterized in that: The steps for obtaining the seventh conversion relationship in step C1 include the following steps: C11: Control the polishing wheel to process the test optical element with different polishing gaps, and record the corresponding force changes at each processing point through the force sensor. In the conversion relationship module, obtain: Among them, represents the said force and the said polishing gap for the eighth conversion relationship; C12: Control the polishing wheel to process at different positions of the test optical element with different polishing gaps, and calculate the volume removal rate of the removal function at each processing point. In the conversion relationship module, obtain: Among them, represents the ninth conversion relationship between the volume removal rate of the removal function and the polishing gap ; C13: In the conversion relationship module, calculate the seventh conversion relationship according to the eighth conversion relationship and the ninth conversion relationship, that is: Among them, represents the seventh conversion relationship.

12. The magnetorheological polishing method with a variable removal function according to claim 11, characterized in that: In step C3, control the magnetorheological machining module to move to the current machining position When, for the current force measured by the force sensor and the force change threshold are compared: If the current force is less than the force change threshold , do not calculate the change of the current removal function; If the current force is greater than or equal to the force change threshold , calculate the change of the current removal function: If the current force is less than the maximum force , calculate the removal function corresponding to the current machining point through the following formula , and then obtain the variable removal function set : : Among them, represents the volume removal rate of the removal function corresponding to the current machining point; ​ If the current force is greater than or equal to the maximum force , the removal function corresponding to the current machining point is obtained through the following formula , and then the variable removal function set is obtained : Among them, represents the maximum force corresponding to the maximum volume removal rate of the removal function.

13. A magnetorheological polishing method for actuator adjustment, based on the magnetorheological polishing equipment adjusted based on a force sensor according to any one of claims 1 to 5, characterized in that: Include the following steps: D1: Set the force change threshold and the maximum value regulation of the actuator group; D2: Control the movement of the magnetorheological machining module to the current machining position When comparing the current force measured by the force sensor with the force change threshold: If the current force is less than the force change threshold, execute step D4; If the current force is greater than the force change threshold, execute step D3; D3: If the current position change of the polishing wheel is less than the maximum value regulation, control the output displacement of the actuator group to be the current position change, and process the optical element to be processed; if the current position change of the polishing wheel is greater than the maximum value regulation, control the output displacement of the actuator group to be the maximum value regulation, and process the optical element to be processed; D4: Control the magnetorheological processing module to move to the next processing position, and repeat steps D2 and D3 until the magnetorheological processing module traverses all the processing points on the optical element to be processed.

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