Magnetorheological polishing equipment and method for adjusting electromagnet based on force sensor

Abstract

The invention relates to the technical field of optical machining, in particular to magneto-rheological polishing equipment and method based on a force sensor adjusting electromagnet, and the equipment comprises a robot, a control unit, a magneto-rheological machining module and a force sensor; the magneto-rheological machining module and the force sensor are arranged at the free end of 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 machining process of magnetorheological machining is measured through a force sensor, then parameters related to an electromagnet 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 field of optical processing technology, and in particular relates to a magnetorheological polishing device and method based on a force sensor to adjust an electromagnet. Background Art

[0002] Magnetorheological finishing (MRF) is an advanced optical manufacturing technology that has developed in recent years. It boasts numerous advantages, including stable removal function, controllable edge effects, minimal subsurface damage, no photocopying, strong reshaping capabilities, and high machining accuracy. Consequently, MRF has garnered widespread attention in high-precision optical processing. Existing MRF processes primarily integrate MRF modules onto CNC machine tools. However, CNC machine tools have several limitations (such as low degrees of freedom, large footprint, and high cost), which limit the deviation of aspheric surfaces and make precise pose control along the surface normal difficult. In response to these shortcomings of CNC machine tools, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. Six-degree-of-freedom industrial robots have the advantages of high degrees of freedom, small footprint, large processing range and low cost, which make up for the shortcomings of CNC machine tools. Therefore, when the magnetorheological polishing module is integrated into the industrial robot, theoretically, high-precision processing of large-aperture complex curved optical components can be achieved. However, when the industrial robot is combined with the magnetorheological polishing module, there are factors such as processing, assembly, load, trajectory planning and reduction ratio, which lead to low execution accuracy of the robot's free end and large changes in the polishing gap during processing. At the same time, magnetorheological polishing technology is an optical processing technology with high determinism of the removal function. It has high requirements for the change of the polishing gap during the polishing process. Generally, the polishing gap of the magnetorheological CNC machining center changes in tens of microns (PV<0.1mm), while the trajectory accuracy of common commercial robots is generally in the sub-millimeter to millimeter range, which leads to large changes in the polishing gap during processing. Large changes in the polishing gap will lead to a decrease in the certainty of the removal function, affecting the final processing accuracy. Therefore, the motion accuracy of currently commercial large-scale six-degree-of-freedom industrial robots often cannot meet the requirements of magnetorheological polishing technology for changes in the removal function during high-precision polishing.

[0003] To address the issue of low robot motion precision, real-time control solutions for constant-force grinding and polishing have become a research hotspot. Force-position control has become a common method for controlling constant-force robot grinding and polishing. A common application involves placing a force sensor between the machining tool and the robot. By measuring force changes, the position error is calculated. Constant-force control is then achieved by compensating for this position error using the robot itself or other motion compensation mechanisms. Summary of the Invention

[0004] In view of this, the present invention aims to provide a magnetorheological polishing device and method for adjusting an electromagnet based on a force sensor, which measures the real-time change of the force during magnetorheological processing through the force sensor, and then adjusts the parameters related to the electromagnet in real time, so as to realize 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 for adjusting an electromagnet based on a force sensor includes a robot, a control unit, a magnetorheological processing module and a force sensor; wherein: the magnetorheological processing module is connected to the free end of the robot through the force sensor; the robot drives the magnetorheological processing module to process an optical element, and during the processing, the force sensor measures the force applied by the magnetorheological processing module to the optical element; the control unit internally includes: a conversion relationship module, which obtains a first conversion relationship according to the magnetic field strength of the electromagnet in the magnetorheological processing module and the force value collected by the force sensor, and obtains a second conversion relationship according to the position of the electromagnet and the force value; a real-time regulation module, which adjusts the magnetic field strength in combination with the first conversion relationship, or adjusts the position of the electromagnet in combination with the second conversion relationship to make the removal function stable during the process of processing the optical element.

[0006] Furthermore, the magnetorheological processing module further includes a transmission belt, a polishing motor, a nozzle, a supply system, a real-time adjustment device and a magnetorheological mounting bracket; wherein, the magnetorheological mounting bracket is connected to the force sensor, the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting bracket, and the real-time adjustment device is connected to the polishing wheel, so that the real-time adjustment device adjusts the position of the polishing wheel, thereby changing the polishing gap of the polishing wheel; the polishing motor is connected to the bearing of the polishing wheel through the transmission belt, so that the polishing motor controls the rotation of the polishing wheel, and then 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 electromagnet is connected to the real-time adjustment device and is located near the working point of the polishing wheel, so that the magnetorheological fluid changes its stiffness under the influence of the magnetic field strength of the electromagnet; at the same time, the real-time adjustment device adjusts the magnetic field strength and the distance between the electromagnet and the polishing wheel.

[0007] Further, the real-time adjustment device includes a displacement output motor, a lead screw, a support fixing frame, and a current intensity controller; the support fixing frame is arranged on the magnetorheological mounting frame; the displacement output motor is arranged on the support fixing frame and is connected to the lead screw arranged on the support fixing frame; the electromagnet or the polishing wheel is connected to the nut on the lead screw; the current intensity controller is arranged on the support fixing frame and is connected to the electromagnet; the current intensity controller supplies power to the electromagnet to generate a magnetic field; the current intensity controller is connected to the control unit, and the control unit sends a control signal to the current intensity controller, and the current intensity controller adjusts the current transmitted to the electromagnet according to the control signal, thereby changing the magnetic field intensity of the electromagnet.

[0008] Further, the force sensor, 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.

[0009] A magnetorheological polishing method based on magnetic field intensity, based on the magnetorheological polishing equipment for adjusting the electromagnet based on the 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 force and polishing gap in the conversion relationship module; A2: Under different polishing gaps, separately change the magnetic field intensity, and process at different positions of the test optical element, and obtain the fourth conversion relationship between the polishing gap and the magnetic field intensity 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 magnetic field intensity; combine the first conversion relationship, the force change threshold, and the maximum magnetic field intensity to 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 adjustments to the magnetorheological processing module.

[0010] Further, in step A4, when controlling the magnetorheological processing module to move to the current processing position 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 no adjustment is made to the current magnetic field intensity ; If the current force is greater than or equal to the force change threshold the current magnetic field intensity is adjusted; If the current magnetic field strength is less than the maximum magnetic field strength , the current magnetic field strength is adjusted according to the following formula: ; wherein represents the first conversion relationship; If the current magnetic field strength is greater than or equal to the maximum magnetic field strength , the current magnetic field strength is adjusted to the maximum magnetic field strength .

[0011] A magnetorheological polishing method based on the adjustment of the electromagnet position, based on the magnetorheological polishing equipment for adjusting the electromagnet provided by the present invention, 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: Under different polishing gaps, separately change the position of the electromagnet and process at different positions of the test optical element, and obtain the sixth conversion relationship between the polishing gap and the electromagnet 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 the force change threshold and the maximum electromagnet position; combine the second conversion relationship, the force change threshold and the maximum electromagnet position, control the magnetorheological processing module to process the optical element to be processed, and during the processing, the real-time control module makes real-time adjustments to the magnetorheological processing module.

[0012] 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 electromagnet position ; If the current force is greater than or equal to the force change threshold , adjust the current electromagnet position : If the current electromagnet position is less than the maximum electromagnet position , according to the following formula, the current electromagnet position Make adjustments: ; Among them, represents the second conversion relationship; If the current electromagnet position is greater than or equal to the maximum electromagnet position , adjust the current electromagnet position to the maximum electromagnet position .

[0013] A magnetorheological polishing method based on magnetic field strength and polishing wheel movement, and a magnetorheological polishing device for adjusting an electromagnet based on a force sensor provided by the present invention, comprising the following steps: C1: Control the magnetorheological processing module to process the test optical element, and obtain the seventh conversion relationship between the polishing gap of the polishing wheel and the force value measured by the force sensor through the conversion relationship module during the processing; C2: Set the force change threshold, the maximum magnetic field strength, and the maximum polishing gap; combine the seventh conversion relationship, the force change threshold, the maximum magnetic field strength, and the maximum polishing gap, 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 adjustments to the magnetorheological processing module.

[0014] Furthermore, in step C2, 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 polishing gap ; If the current force is greater than or equal to the force change threshold , adjust the current polishing gap : If the current polishing gap is less than the maximum polishing gap , and the current magnetic field strength is less than the maximum magnetic field strength , the current magnetic field strength and the current polishing gap are adjusted respectively according to the following formulas: ; ; Among them, represents the seventh conversion relationship, It represents the initial set polishing gap, r represents the distance between the lowest point of the polishing wheel and the electromagnet, M represents the magnetic moment of the electromagnet, and k is the proportionality coefficient; If the current polishing gap is greater than or equal to the maximum polishing gap , and the current magnetic field strength is greater than or equal to the maximum magnetic field strength , adjust the current polishing gap to the maximum polishing gap , and correspondingly adjust the current magnetic field strength to the maximum magnetic field strength .

[0015] Compared with the prior art, the present invention can achieve the following beneficial effects: In the magnetorheological polishing equipment and method for adjusting an electromagnet based on a force sensor according to the present invention, during the six-dimensional machining of the magnetorheological machining module driven by a robot, the force applied by the magnetorheological machining module to the optical element is measured in real time by the force sensor, so as to adjust the position or magnetic field strength of the electromagnet in the magnetorheological machining module in real time, and further realize the real-time constant control of the removal function change under the coupling of multiple factors during the machining process of the optical element; at the same time, the acquisition of pose information does not need to rely 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

[0016] 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 is a schematic structural view of the magnetorheological polishing equipment for adjusting an electromagnet based on a force sensor according to an embodiment of the present invention from one perspective; Figure 2 is a schematic structural view of the magnetorheological polishing equipment for adjusting an electromagnet based on a force sensor according to an embodiment of the present invention from another perspective; Figure 3 is a schematic structural view of the magnetorheological machining module according to an embodiment of the present invention; Figure 4 is a schematic structural view of the real-time adjustment device according to an embodiment of the present invention.

[0017] Description of the reference numerals: 1. Robot; 2. Control unit; 3. Force sensor; 4. Test bench; 5. Optical element to be processed; 6. Test optical element; 7. Electromagnet; 8. Polishing wheel; 9. Polishing motor; 10. Transmission belt; 11. Nozzle; 12. Real-time adjustment device; 13. Magnetorheological mounting bracket; 14. Displacement output motor; 15. Guide rail; 16. Slide block; 17. Lead screw; 18. Lead nut; 19. Support fixing bracket; 20. Connecting plate; 21. Current intensity controller. Detailed implementation manner

[0018] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further elaborates on the present invention in conjunction with 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.

[0019] 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.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are 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, and thus 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 indicating 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 "plurality" is two or more.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounting", "connecting", "coupling" 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 according to specific circumstances.

[0022] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0023] As Figure 1 andFigure 2 As shown in the figure, the magnetorheological polishing equipment for adjusting an electromagnet based on a force sensor according to the embodiment of the present invention includes a robot 1, a control unit 2, a magnetorheological processing module, and a force sensor 3. The magnetorheological processing module is arranged at the free end of the robot 1, and the force sensor 3 is arranged on the magnetorheological processing module and the robot 1, so that the robot 1 drives the magnetorheological processing module to process an optical element 5 to be processed or a test optical element 6 placed on a test bench 4, and during the processing, the force sensor 3 measures the force applied by the magnetorheological processing module to the optical element 5 to be processed or the test optical element 6. In the embodiment of the present invention, preferably, the force sensor 3 is arranged between the magnetorheological processing module 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 prolonged, thereby reducing the complexity and cost of the equipment, and at the same time improving the assembly accuracy of the equipment and the final motion accuracy of the equipment.

[0024] The interior of the control unit 2 includes a conversion relationship module and a real-time regulation module. The conversion relationship module obtains a first conversion relationship based on the magnetic field strength of the electromagnet 7 in the magnetorheological processing module and the force value collected by the force sensor 3, and obtains a second conversion relationship based on the electromagnet position of the electromagnet 7 and the force value. In the embodiment of the present invention, the electromagnet position is defined as the distance between the electromagnet 7 and the optical element 5 to be processed or the test optical element 6. The real-time regulation module adjusts the magnetic field strength in combination with the first conversion relationship, or adjusts the electromagnet position in combination with the second conversion relationship to stabilize the removal function during the process of processing the optical element 5 to be processed.

[0025] Figure 3 Figure (a) therein shows a schematic structural diagram of the magnetorheological processing module from one perspective, Figure 3 and figure (b) therein shows a schematic structural diagram of the magnetorheological processing module from another perspective. As Figure 3As shown in the figure, the magnetorheological machining module further includes a polishing motor 9, a transmission belt 10, a nozzle 11, a supply system, a real-time adjustment device 12, and a magnetorheological mounting bracket 13. The magnetorheological mounting bracket 13 is connected to the force sensor 3. The polishing wheel 8 and the real-time adjustment device 12 are mounted on the magnetorheological mounting bracket 13, and the real-time adjustment device 12 is connected to the polishing wheel 8 through a connecting plate 20. Specifically, the head end of the connecting plate 20 is mounted on the real-time adjustment device 12, and the polishing wheel 8 is mounted at the end of the connecting plate 20, so that the real-time adjustment device 12 adjusts the position of the polishing wheel 8, thereby changing the polishing gap of the polishing wheel 8. The polishing motor 9 is mounted on the connecting plate 20. The output end of the polishing motor 9 passes through the connecting plate 20, and the bearing of the polishing wheel 8 passes through the end of the connecting plate 20. The output end of the polishing motor 9 is connected to the bearing of the polishing wheel 8 through the transmission belt 10, so that the polishing motor 9 controls the polishing wheel 8 to rotate. In the embodiment of the present invention, the manner in which the polishing motor 9 drives the polishing wheel 8 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 arranged on the magnetorheological mounting bracket 13 along the rotation direction of the polishing wheel 8. The supply system conveys the magnetorheological fluid to the nozzle 11, and the nozzle 11 sprays the magnetorheological fluid to the working point of the polishing wheel 8, so that the polishing wheel 8 processes the optical element 5 to be processed or the test optical element 6 with the magnetorheological fluid as the medium. In the embodiment of the present invention, it is stipulated that the working point of the polishing wheel 8 is the closest point along the normal direction of the surface of the optical element 5 to be processed or the test optical element 6 and the surface of the optical element 5 to be processed or the test optical element 6. The electromagnet 7 is connected to the real-time adjustment device 12 through the connecting plate 20 and is arranged close to the working point of the polishing wheel 8. Specifically, the head end of the connecting plate 20 is mounted on the real-time adjustment device 12, and the electromagnet 7 is mounted at the end of the connecting plate 20, so that the magnetorheological fluid changes its stiffness under the influence of the magnetic field strength of the electromagnet 7, and the polishing wheel 8 processes the optical element 5 to be processed or the test optical element 6 with the magnetorheological fluid with a certain stiffness as the medium. At the same time, the real-time adjustment device 12 adjusts the magnetic field strength and the distance between the electromagnet 7 and the polishing wheel 8. In addition, in the embodiment of the present invention, the supply system uses the DFLD vertical multi-stage pump of Shanghai Dongfang Pump Industry Co., Ltd.

[0026] The structure of the real-time adjustment device 12 that controls the electromagnet 7 and the polishing wheel 8 is as Figure 4As shown in the figure, it includes a displacement output motor 14, a lead screw 17, a nut 18, a support fixing frame 19, and a current intensity controller 21. The lead screw 17 and the nut 18 with balls together form a ball screw. The support fixing frame 19 is installed on the magnetorheological mounting frame 13, and the displacement output motor 14 is installed on the top of the support fixing frame 19. The displacement output motor 14 is connected to the lead screw 17 installed on the support fixing frame 19. The current intensity controller 21 is installed on the support fixing frame 19. The current intensity controller 21 is connected to the electromagnet 7 through a wire, and is used to energize the electromagnet 7 to generate a magnetic field. At the same time, the current intensity controller 21 is communicatively connected to the control unit 2. The control unit 2 sends a control signal to the current intensity controller 21, and the current intensity controller 21 adjusts the current transmitted to the electromagnet 7 according to the control signal, thereby changing the magnetic field intensity of the electromagnet 7. In the embodiment of the present invention, in order to ensure that the electromagnet 7 or the polishing wheel 8 can move stably along the lead screw 17, it is preferably provided with two guide rails 15 on the support fixing frame 19. The two guide rails 15 are parallel to the lead screw 17 and are located on both sides of the lead screw 17. At this time, the head end of the connecting plate 20 is fixedly connected to the nut on the lead screw 17 and the sliders 16 on the two guide rails 15 at the same time. During the processing, the control unit 2 sends a control signal to the displacement output motor 14. When the displacement output motor 14 drives the lead screw 17 to rotate, the lead screw 17 cooperates with the two guide rails 15 to pull the connecting plate 20, thereby driving the electromagnet 7 or the polishing wheel 8 to move stably along the lead screw 17. In the embodiment of the present invention, the current intensity controller 21 preferably adopts the DA conversion module of the Smart200 series of Siemens Corporation.

[0027] The robot 1, the force sensor 3, and the real-time adjustment device 12 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 force sensor 3 through the communication line. The control unit 2 sends a control signal for changing the position of the electromagnet 7 or the polishing wheel 8 to the displacement output motor 14 in the real-time adjustment device 12 through the communication line. The control unit 2 sends a control signal for changing the magnetic field intensity of the electromagnet 7 to the current intensity controller 21 in the real-time adjustment device 12 through the communication line. Since a strong magnetic area is generated around the polishing wheel 8 during the polishing operation, the communication line avoids the strong magnetic area.

[0028] Based on the magnetorheological polishing equipment for adjusting the electromagnet based on the force sensor described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological polishing method for adjusting the electromagnet based on the force sensor, including a magnetorheological polishing method based on the magnetic field intensity, a magnetorheological polishing method based on the adjustment of the position of the electromagnet, and a magnetorheological polishing method based on the magnetic field intensity and the movement of the polishing wheel.

[0029] Specific Embodiment 1: The magnetorheological polishing method based on magnetic field strength provided in this specific embodiment, and the magnetorheological polishing equipment for adjusting the electromagnet based on the force sensor according to the embodiment of the present invention, in combination with Figures 1 to 4 , includes the following steps: A1: Control the polishing wheel 8 to process the test optical element 6 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: ; Wherein, represents the force and the third conversion relationship between the polishing gap ; In this specific embodiment, specifically, control the polishing wheel 8 to perform fixed-point processing on the test optical element 6 for a certain period of time with different polishing gaps; A2: Under different polishing gaps, separately change the magnetic field strength, and process at different positions of the test optical element 6, and record the numerical changes of the polishing gap and the magnetic field strength at the same time, and then obtain in the conversion relationship module: ; Wherein, represents the polishing gap and the fourth conversion relationship between the magnetic field strength ; In this specific embodiment, specifically, control the polishing wheel 8 to perform fixed-point processing on the test optical element 6 for a certain period of time with different magnetic field strengths under different polishing gaps; A3: In the conversion relationship module, calculate the first conversion relationship according to the third conversion relationship and the fourth conversion relationship as: ; Wherein, represents the first conversion relationship.

[0030] A4: Set the force change threshold and the maximum magnetic field strength; combine the first conversion relationship, the force change threshold and the maximum magnetic field strength, control the magnetorheological processing module to process the optical element 5 to be processed, and during the processing, the real-time regulation module performs real-time adjustment on the magnetorheological processing module. The force change threshold and the maximum magnetic field strength are adaptively set according to the actual situation, and this specific embodiment does not limit this. The specific process of step A4 is: When controlling the magnetorheological processing module to move to the current processing 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 , that is , without adjusting the current magnetic field strength Adjustment is not performed; If the current force is greater than or equal to the force change threshold , that is , adjust the current magnetic field strength as follows: If the current magnetic field strength is less than the maximum magnetic field strength , that is , when adjusting the current magnetic field strength according to the following formula: ; If the current magnetic field strength is greater than or equal to the maximum magnetic field strength , that is , when adjusting the current magnetic field strength is adjusted to the maximum magnetic field strength .

[0031] Specific Embodiment 2: The magnetorheological polishing method based on the adjustment of the electromagnet position provided in this specific embodiment, the magnetorheological polishing equipment for adjusting the electromagnet based on the force sensor according to the embodiments of the present invention, in combination with Figures 1 to 4 , includes the following steps: B1: Control the polishing wheel 8 to process the test optical element 6 with different polishing gaps, and record the force changes at each processing point through the force sensor 3, and obtain in the conversion relationship module: ; Among them, represents the fifth conversion relationship between the force and the polishing gap ; in this specific embodiment, specifically control the polishing wheel 8 to perform fixed-point processing on the test optical element 6 for a certain period of time with different polishing gaps; B2: Keep the force unchanged, at different polishing gaps, separately change the position of the electromagnet, and process at different positions of the test optical element 6, and record the numerical changes of the polishing gap and the electromagnet position at the same time, and obtain in the conversion relationship module: ; Among them, represents the sixth conversion relationship between the polishing gap and the electromagnet position ; in this specific embodiment, specifically control the polishing wheel 8 to perform fixed-point processing on the test optical element 6 for a certain period of time with different magnetic field strengths at different polishing gaps; B3: In the conversion relationship module, the second conversion relationship is calculated based on the fifth conversion relationship and the sixth conversion relationship as follows: ; where represents the second conversion relationship.

[0032] B4: Set the force change threshold and the maximum electromagnet position; in combination with the second conversion relationship, the force change threshold, and the maximum electromagnet position, control the magnetorheological processing module to process the optical element 5 to be processed, and during the processing, the real-time regulation module makes real-time adjustments to the magnetorheological processing module. The force change threshold and the maximum electromagnet position are adaptively set according to the actual situation, and this specific embodiment does not limit this. The specific process of step B4 is as follows: Control the magnetorheological processing module to move to the current processing 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 , that is , do not adjust the current electromagnet position ; If the current force is greater than or equal to the force change threshold , that is , adjust the current electromagnet position as follows: If the current electromagnet position is less than the maximum electromagnet position , that is when, adjust the current electromagnet position according to the following formula: ; If the current electromagnet position is greater than or equal to the maximum electromagnet position , that is when, adjust the current electromagnet position to the maximum electromagnet position .

[0033] Specific Embodiment 3: The magnetorheological polishing method based on magnetic field intensity and polishing wheel movement provided in this specific embodiment, according to the magnetorheological polishing device for adjusting an electromagnet based on a force sensor in the embodiment of the present invention, in combination with Figures 1 to 4 , includes the following steps: C1: Control the magnetorheological machining module to machine the test optical element 6, and obtain the seventh conversion relationship between the polishing gap of the polishing wheel 8 and the force value measured by the force sensor 3 during the machining process. The specific process is as follows: Keep the position between the polishing wheel 8 and the electromagnet 7 unchanged, control the polishing wheel 8 to machine the test optical element 6 with different polishing gaps, and record the force changes at each machining point through the force sensor 3. In the conversion relationship module, obtain: ; Among them, represents the force and the polishing gap The seventh conversion relationship between them. In this specific embodiment, specifically control the polishing wheel 8 to perform fixed-point machining on the test optical element 6 for a period of time with different polishing gaps.

[0034] C2: Set the force change threshold, the maximum magnetic field strength, and the maximum polishing gap; combine the seventh conversion relationship, the force change threshold, the maximum magnetic field strength, and the maximum polishing gap to control the magnetorheological machining module to machine the optical element 5 to be machined, and during the machining process, the real-time regulation module makes real-time adjustments to the magnetorheological machining module. The force change threshold, the maximum magnetic field strength, and the maximum polishing gap are adaptively set according to the actual situation, and this specific embodiment does not limit this. The specific process of step C2 is as follows: 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 , that is , do not adjust the current polishing gap ; If the current force is greater than or equal to the force change threshold , that is , adjust the current polishing gap : If the current polishing gap is less than the maximum polishing gap , and the current magnetic field strength is less than the maximum magnetic field strength , that is and , the current magnetic field strength and the current polishing gap are adjusted according to the following formula: ; ; Among them, represents the seventh conversion relationship; represents the initially set polishing gap, r represents the distance between the electromagnet 7 and the lowest point of the polishing wheel 8, M represents the magnetic moment, and k is a proportionality coefficient; If the current polishing gap is greater than or equal to the maximum polishing gap , and the current magnetic field strength is greater than or equal to the maximum magnetic field strength , that is and , adjust the current polishing gap to the maximum polishing gap [[ID=2�]], and adjust the current corresponding magnetic field strength to the maximum magnetic field strength .

[0035] All the conversion relationships in the above specific embodiments are obtained by fitting. The fitting process includes and is not limited to importing discrete data into Matlab software and using the polyfit fitting instruction of Matlab software to complete data fitting and 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 items can be more intuitively seen.

[0036] It should be understood that various forms of the processes 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 limitations are imposed herein.

[0037] The above specific embodiments 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 for adjusting an electromagnet based on a force sensor, comprising a robot and a control unit, characterized in that, It further includes a magnetorheological machining module and a force sensor; wherein: the magnetorheological machining module is connected to the free end of the robot through the force sensor; the robot drives the magnetorheological machining module to machine the optical element, and during the machining process, the force sensor measures the machining force applied by the magnetorheological machining module to the optical element; The interior of the control unit includes: A conversion relationship module, which obtains a first conversion relationship based on the magnetic field intensity of the electromagnet in the magnetorheological machining module and the force value collected by the force sensor, and obtains a second conversion relationship based on the position of the electromagnet and the force value; A real-time regulation module, which adjusts the magnetic field intensity in combination with the first conversion relationship, or adjusts the position of the electromagnet in combination with the second conversion relationship to make the removal function stable during the machining of the optical element.

2. The magnetorheological polishing apparatus for adjusting an electromagnet based on a force sensor according to claim 1, wherein: The magnetorheological machining module further includes a transmission belt, a polishing motor, a nozzle, a supply system, a real-time adjustment device, and a magnetorheological mounting bracket; wherein, The magnetorheological mounting bracket is connected to the force sensor, the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting bracket, and the real-time adjustment device is connected to the polishing wheel, so that the real-time adjustment device adjusts the position of the polishing wheel, thereby changing the polishing gap of the polishing wheel; The polishing motor is connected to the polishing wheel through the transmission belt, so that the polishing motor controls the rotation of the polishing wheel, and further the polishing wheel machines 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 electromagnet is connected to the real-time adjustment device and is located near the working point of the polishing wheel, so that the magnetorheological fluid changes its stiffness under the influence of the magnetic field intensity of the electromagnet; at the same time, the real-time adjustment device adjusts the magnetic field intensity and the distance between the electromagnet and the polishing wheel.

3. The magnetorheological polishing apparatus for adjusting an electromagnet based on a force sensor according to claim 2, wherein: The real-time adjustment device includes a displacement output motor, a lead screw, a support fixing bracket, and a current intensity controller; the support fixing bracket is arranged on the magnetorheological mounting bracket; the displacement output motor is arranged on the support fixing bracket and is connected to the lead screw arranged on the support fixing bracket; the electromagnet or the polishing wheel is connected to the nut on the lead screw; the current intensity controller is arranged on the support fixing bracket and is connected to the electromagnet; the current intensity controller energizes the electromagnet to generate a magnetic field; the current intensity controller is connected to the control unit, and the control unit sends a control signal to the current intensity controller, and the current intensity controller adjusts the current transmitted to the electromagnet according to the control signal, thereby changing the magnetic field intensity of the electromagnet.

4. The magnetorheological polishing equipment for adjusting an electromagnet based on a force sensor according to claim 3, wherein: The force sensor, the robot, and the displacement output motor are respectively connected to the control unit to form their respective communication lines, and the control unit receives and sends signals through the corresponding communication lines.

5. A magnetorheological polishing method based on magnetic field intensity, based on the magnetorheological polishing equipment for adjusting an electromagnet based on a force sensor according to any one of claims 1 to 4, characterized in that: It includes the following steps: A1: Control the polishing wheel to process the test optical element with different polishing gaps, 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: Under different polishing gaps, separately change the magnetic field intensity, and process at different positions of the test optical element, and obtain the fourth conversion relationship between the polishing gap and the magnetic field intensity in the conversion relationship module; A3: In the conversion relationship module, calculate the first conversion relationship according to the third conversion relationship and the fourth conversion relationship; A4: Set the force change threshold and the maximum magnetic field intensity; combine the first conversion relationship, the force change threshold and the maximum magnetic field intensity to 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 adjustments to the magnetorheological processing module.

6. The magnetorheological polishing method based on magnetic field strength according to claim 5, 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 magnetic field strength ; If the current force is greater than or equal to the force change threshold , adjust the current magnetic field strength as follows: If the current magnetic field strength is less than the maximum magnetic field strength , the current magnetic field strength is adjusted according to the following formula: ； Among them, represents the first conversion relationship; If the current magnetic field strength is greater than or equal to the maximum magnetic field strength , the current magnetic field strength will be adjusted to the maximum magnetic field strength .

7. A magnetorheological polishing method based on the position adjustment of an electromagnet, which is based on the magnetorheological polishing equipment for adjusting the electromagnet based on a force sensor according to any one of claims 1 to 4, and is characterized in that: It includes the following steps: B1: Control the polishing wheel to process the test optical element with different polishing gaps, 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: Under different polishing gaps, separately change the position of the electromagnet, and process at different positions of the test optical element, and obtain the sixth conversion relationship between the polishing gap and the position of the electromagnet 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 electromagnet position; combine the second conversion relationship, the force change threshold and the maximum electromagnet position to 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 adjustments to the magnetorheological processing module.

8. The magnetorheological polishing method based on the position adjustment of the electromagnet according to claim 7, characterized in that: In step B4, 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 electromagnet position ; If the current force is greater than or equal to the force change threshold , adjust the current electromagnet position as follows: If the current electromagnet position is less than the maximum electromagnet position , adjust the current electromagnet position according to the following formula: ； Among them, represents the second conversion relationship; If the current electromagnet position is greater than or equal to the maximum electromagnet position , adjust the current electromagnet position to the maximum electromagnet position .

9. A magnetorheological polishing method based on magnetic field intensity and the movement of a polishing wheel, based on the magnetorheological polishing equipment for adjusting an electromagnet based on a force sensor according to any one of claims 1 to 4, characterized in that: It includes the following steps: C1: Control the magnetorheological processing module to process the test optical element, and obtain the seventh conversion relationship between the polishing gap of the polishing wheel and the force value measured by the force sensor through the conversion relationship module during the processing; C2: Set the force change threshold, the maximum magnetic field intensity and the maximum polishing gap; combine the seventh conversion relationship, the force change threshold, the maximum magnetic field intensity and the maximum polishing gap to 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 adjustments to the magnetorheological processing module.

10. The magnetorheological polishing method based on magnetic field intensity and polishing wheel movement according to claim 9, characterized in that: In step C2, 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 , do not adjust the current polishing gap ; If the current force is greater than or equal to the force change threshold , adjust the current polishing gap as follows: If the current polishing gap is less than the maximum polishing gap , and the current magnetic field strength is less than the maximum magnetic field strength , the current magnetic field strength and the current polishing gap are adjusted respectively according to the following formulas: ； ； Among them, represents the seventh conversion relationship, represents the initially set polishing gap, r represents the distance between the lowest point of the polishing wheel and the electromagnet, M represents the magnetic moment of the electromagnet, and k is a proportionality coefficient; If the current polishing gap is greater than or equal to the maximum polishing gap , and the current magnetic field strength is greater than or equal to the maximum magnetic field strength , adjust the current polishing gap to the maximum polishing gap , and correspondingly adjust the current magnetic field strength to the maximum magnetic field strength .

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