Magnetorheological finishing apparatus and method for regulating an electromagnet based on a force sensor

Abstract

The application relates to the technical field of optical processing, in particular to a magnetorheological polishing device and method based on force sensor adjustment of electromagnets, wherein the device comprises a robot, a control unit, a magnetorheological processing module and a force sensor; the magnetorheological processing module and the force sensor are arranged at the free end of the robot, the robot drives the magnetorheological processing module to process an optical element, and the force sensor measures the force applied by the magnetorheological processing module to the optical element during the processing; in the method, the real-time change of the force during magnetorheological processing is measured by the force sensor, then the parameters related to the electromagnets are controlled in real time, and the real-time constant control of the removal function is realized.

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 based on force sensor adjustment of electromagnets, which measures the real-time changes in force during magnetorheological processing through force sensors, and then adjusts the parameters related to the electromagnets in real time, thereby achieving real-time constant control of the removal function.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0006] A magnetorheological polishing device based on a force sensor for adjusting an electromagnet comprises 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 via the force sensor; the robot drives the magnetorheological processing module to process an optical element, and during the processing, the force sensor measures the processing force applied to the optical element by the magnetorheological processing module; the control unit internally comprises: a conversion relationship module, which obtains a first conversion relationship based on 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 based on the electromagnet position of the electromagnet and the force value; a real-time control module, which adjusts the magnetic field strength in combination with the first conversion relationship, or adjusts the electromagnet position in combination with the second conversion relationship, so that the removal function is stable during the processing of the optical element.

[0007] Furthermore, the magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a supply system, a real-time adjustment device and a magnetorheological mounting frame; wherein, the magnetorheological mounting frame is connected to the force sensor, the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, 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, thereby causing the polishing wheel to process the optical element; the nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the supply system delivers magnetorheological fluid to the nozzle; the electromagnet is connected to the real-time adjustment device, and the electromagnet is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the electromagnet to change the stiffness of the magnetorheological fluid; at the same time, the real-time adjustment device adjusts the magnetic field strength and the distance between the electromagnet and the polishing wheel.

[0008] Furthermore, the real-time adjustment device includes a displacement output motor, a screw, a support bracket and a current intensity controller; the support bracket is arranged on a magnetorheological mounting bracket; the displacement output motor is arranged on the support bracket and is connected to the screw arranged on the support bracket; the electromagnet or the polishing wheel is connected to the nut on the screw; the current intensity controller is arranged on the support 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 strength of the electromagnet.

[0009] Furthermore, the force sensor, the robot and the displacement output motor are respectively connected to the control unit to form respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

[0010] A magnetorheological polishing method based on magnetic field strength, based on a magnetorheological polishing device based on a force sensor to adjust an electromagnet provided by the present invention, comprises the following steps:

[0011] A1: Control the polishing wheel to process the test optical element with different polishing gaps, and use the force sensor to record the force changes at each processing point. The third conversion relationship between force and polishing gap is obtained in the conversion relationship module;

[0012] A2: Under different polishing gaps, the magnetic field strength is changed individually, and processing is performed at different positions of the test optical element. The fourth conversion relationship between the polishing gap and the magnetic field strength is obtained in the conversion relationship module;

[0013] A3: In the conversion relationship module, a first conversion relationship is calculated based on the third conversion relationship and the fourth conversion relationship;

[0014] A4: Setting a force change threshold and a maximum magnetic field strength; combining the first conversion relationship, the force change threshold and the maximum magnetic field strength, controlling 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.

[0015] Further, in step A4, the magnetorheological processing module is controlled to move to the current processing position. When the current force measured by the force sensor Force change threshold For comparison:

[0016] If the current force Less than the force change threshold , not the current magnetic field strength Make adjustments;

[0017] If the current force Greater than or equal to the force change threshold , for the current magnetic field strength Make adjustments;

[0018] If the current magnetic field strength Less than the maximum magnetic field strength , for the current magnetic field strength Adjust according to the following formula:

[0019] ;

[0020] in, Indicates the first conversion relationship;

[0021] If the current magnetic field strength Greater than or equal to the maximum magnetic field strength , the current magnetic field strength Adjust to maximum magnetic field strength .

[0022] A magnetorheological polishing method based on electromagnet position adjustment, based on the magnetorheological polishing device based on force sensor adjustment of electromagnet provided by the present invention, comprises the following steps:

[0023] B1: Control the polishing wheel to process the test optical element with different polishing gaps, and use the force sensor to record the force changes at each processing point. The fifth conversion relationship between force and polishing gap is obtained in the conversion relationship module;

[0024] B2: Under different polishing gaps, the electromagnet position is changed individually, and processing is performed at different positions of the test optical element, and the sixth conversion relationship between the polishing gap and the electromagnet position is obtained in the conversion relationship module;

[0025] B3: In the conversion relationship module, a second conversion relationship is calculated based on the fifth conversion relationship and the sixth conversion relationship;

[0026] B4: Setting the force change threshold and the maximum electromagnet position; combining the second conversion relationship, the force change threshold and the maximum electromagnet position, controlling 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.

[0027] Further, in step B4, the magnetorheological processing module is controlled to move to the current processing position. When the current force measured by the force sensor Force change threshold For comparison:

[0028] If the current force Less than the force change threshold , incorrect current electromagnet position Make adjustments;

[0029] If the current force Greater than or equal to the force change threshold , for the current electromagnet position Make adjustments:

[0030] If the current electromagnet position Less than the maximum solenoid position , according to the following formula, the current electromagnet position Make adjustments:

[0031] ;

[0032] in, Represents the second conversion relationship;

[0033] If the current electromagnet position Greater than or equal to the maximum electromagnet position , the current electromagnet position Adjust to the maximum solenoid position .

[0034] A magnetorheological polishing method based on magnetic field strength and polishing wheel movement, based on a magnetorheological polishing device based on force sensor-adjusted electromagnet provided by the present invention, comprises the following steps:

[0035] 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;

[0036] C2: Set the force change threshold, maximum magnetic field strength and maximum polishing gap; combine the seventh conversion relationship, force change threshold, maximum magnetic field strength and maximum polishing gap to control the magnetorheological processing module to process the optical element to be processed, and during the processing, the real-time control module adjusts the magnetorheological processing module in real time.

[0037] Further, in step C2, the magnetorheological processing module is controlled to move to the current processing position When the current force measured by the force sensor Force change threshold For comparison:

[0038] If the current force Less than the force change threshold , not the current polishing gap Make adjustments;

[0039] If the current force Greater than or equal to the force change threshold , for the current polishing gap Make adjustments:

[0040] If the current polishing gap Smaller than the maximum polishing gap , and the current magnetic field strength Less than the maximum magnetic field strength , current magnetic field strength and current polishing gap Adjust according to the following formula:

[0041] ;

[0042] ;

[0043] in, 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 the proportional coefficient;

[0044] If the current polishing gap Greater than or equal to the maximum polishing gap , and the current magnetic field strength Greater than or equal to the maximum magnetic field strength , the current polishing gap Adjust to maximum polishing gap , current magnetic field strength Corresponding adjustment to the maximum magnetic field strength .

[0045] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0046] In the magnetorheological polishing equipment and method based on force sensor adjustment of electromagnets created by the present invention, the force sensor is used to measure in real time the force applied by the magnetorheological processing module to the optical element during six-dimensional processing driven by the robot, thereby adjusting the position or magnetic field strength of the electromagnet in the magnetorheological processing module in real time, thereby realizing real-time constant control of the removal function change under multi-factor coupling during the processing of the optical element; at the same time, the acquisition of posture information does not need to rely on the actual processing process, and the posture error information of the processing equipment can be obtained during the processing trial run (in which magnetorheological fluid is not introduced and no processing effect is produced), and there is no need 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

[0047] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0048] Figure 1 A schematic structural diagram of a magnetorheological polishing device based on a force sensor to adjust an electromagnet according to an embodiment of the present invention from one perspective;

[0049] Figure 2 A schematic structural diagram of a magnetorheological polishing device based on a force sensor to adjust an electromagnet according to an embodiment of the present invention from another perspective;

[0050] Figure 3 A schematic structural diagram of a magnetorheological processing module according to an embodiment of the present invention;

[0051] Figure 4 This is a structural diagram of the real-time adjustment device described in an embodiment of the present invention.

[0052] Description of reference numerals:

[0053] 1. Robot; 2. Control unit; 3. Force sensor; 4. Laboratory 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. Slider; 17. Lead screw; 18. Nut; 19. Support bracket; 20. Connecting plate; 21. Current intensity controller. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is 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 of the present invention.

[0055] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0056] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations 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 therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0057] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0058] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0059] like Figure 1 and Figure 2 As shown, the magnetorheological polishing device based on force sensor adjustment electromagnet described in 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 the optical element 5 to be processed or the test optical element 6 placed on the experimental table 4, and during the processing, the force sensor 3 measures the processing 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, it is preferred to set the force sensor 3 between the magnetorheological processing module and the robot 1, which simplifies the mechanical structure and reduces the weight of the magnetorheological processing module; in addition, by connecting 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, and the complexity and cost of the equipment are reduced, while the assembly accuracy of the equipment is improved and the final movement accuracy of the equipment is improved.

[0060] The control unit 2 internally includes a conversion relationship module and a real-time control module. The conversion relationship module derives 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 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 to be processed 5 or the test optical element 6. The real-time control module adjusts the magnetic field strength based on the first conversion relationship or adjusts the electromagnet position based on the second conversion relationship to achieve destabilization of the function during the processing of the optical element to be processed 5.

[0061] Figure 3 (a) shows a schematic structural diagram of the magnetorheological processing module from one perspective. Figure 3 (b) shows the schematic structural diagram of the magnetorheological processing module from another perspective. Figure 3As shown, the magnetorheological processing module also 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 frame 13. The magnetorheological mounting frame 13 is connected to the force sensor 3, and the polishing wheel 8 and the real-time adjustment device 12 are mounted on the magnetorheological mounting frame 13. 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 on 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, and the output end of the polishing motor 9 passes through the connecting plate 20. 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 rotation of the polishing wheel 8. The manner in which the polishing motor 9 drives the polishing wheel 8 to rotate in the embodiment of the present invention can be referred to the invention patent application with Chinese patent publication number CN118322074A, publication date July 12, 2024, and patent name "Self-rotating polishing module processing system". The nozzle 11 is arranged on the magnetorheological mounting frame 13 along the rotation direction of the polishing wheel 8, and the supply system delivers magnetorheological fluid to the nozzle 11. The nozzle 11 sprays magnetorheological fluid toward the working point of the polishing wheel 8, thereby causing the polishing wheel 8 to process the optical element to be processed 5 or the test optical element 6 with the magnetorheological fluid as the medium. In the embodiment of the present invention, the working point of the polishing wheel 8 is specified as the closest point between the polishing wheel 8 and the surface of the optical element to be processed 5 or the test optical element 6 along the normal direction of the surface of the optical element to be processed 5 or the test optical element 6. The electromagnet 7 is connected to the real-time adjustment device 12 via the connecting plate 20, and the electromagnet 7 is placed 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 on the end of the connecting plate 20. The magnetorheological fluid is affected by the magnetic field strength of the electromagnet 7, which changes the rigidity of the magnetorheological fluid, so that the polishing wheel 8 uses the magnetorheological fluid with a certain rigidity as a medium to process the optical element 5 to be processed or the test optical element 6. 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 adopts the DFLD vertical multi-stage pump of Shanghai Dongfang Pump Industry Co., Ltd.

[0062] The structure of the real-time adjustment device 12 for controlling the electromagnet 7 and the polishing wheel 8 is as follows: Figure 4As shown, the system includes a displacement output motor 14, a lead screw 17, a nut 18, a support bracket 19, and a current intensity controller 21. The lead screw 17 and the nut 18 with a ball bearing together form a ball screw. The support bracket 19 is mounted on the magnetorheological mounting frame 13. The displacement output motor 14 is mounted on top of the support bracket 19. The displacement output motor 14 is connected to the lead screw 17 mounted on the support bracket 19. The current intensity controller 21 is mounted on the support bracket 19. The current intensity controller 21 is connected to the electromagnet 7 via a wire and is used to energize the electromagnet 7 to generate a magnetic field. The current intensity controller 21 is also in communication with the control unit 2. The control unit 2 sends a control signal to the current intensity controller 21. The current intensity controller 21 adjusts the current transmitted to the electromagnet 7 based on the control signal, thereby changing the magnetic field strength of the electromagnet 7. In this embodiment of the present invention, to ensure that the electromagnet 7 or polishing wheel 8 can move stably along the lead screw 17, two guide rails 15 are preferably provided on the support frame 19. The two guide rails 15 are parallel to the lead screw 17 and located on both sides of the lead screw 17. In this case, 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. 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 polishing wheel 8 to move stably along the lead screw 17. In this embodiment of the present invention, the current intensity controller 21 preferably adopts the Smart200 series DA conversion module of Siemens.

[0063] The robot 1, force sensor 3, and real-time adjustment device 12 are each connected to the control unit 2 to form their own communication circuits, allowing the control unit 2 to receive and send signals via the corresponding communication circuits. Specifically, the control unit 2 receives signals from the force sensor 3 via the communication circuits. It then sends control signals to the displacement output motor 14 in the real-time adjustment device 12 via the communication circuits to change the position of the electromagnet 7 or polishing wheel 8. Furthermore, the control unit 2 sends control signals to the current intensity controller 21 in the real-time adjustment device 12 via the communication circuits to change the magnetic field strength of the electromagnet 7. Because a strong magnetic field is generated around the polishing wheel 8 during polishing, the communication circuits are designed to avoid such strong magnetic fields.

[0064] Based on the magnetorheological polishing equipment based on force sensor to adjust electromagnets as described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological polishing method based on force sensor to adjust electromagnets, including a magnetorheological polishing method based on magnetic field strength, a magnetorheological polishing method based on electromagnet position adjustment, and a magnetorheological polishing method based on magnetic field strength and polishing wheel movement.

[0065] Specific embodiment 1: The magnetorheological polishing method based on magnetic field strength provided in this specific embodiment, the magnetorheological polishing device based on force sensor adjustment electromagnet according to the invention embodiment, combined with Figures 1 to 4 , including the following steps:

[0066] A1: Control the polishing wheel 8 to process the test optical element 6 with different polishing gaps, and use the force sensor 3 to record the force changes at each processing point. The following is obtained in the conversion relationship module:

[0067] ;

[0068] in, Expressive power Polishing gap In this specific embodiment, specifically for controlling the polishing wheel 8 to perform fixed-point processing on the test optical element 6 at one end of the time with different polishing gaps;

[0069] A2: Under different polishing gaps, the magnetic field strength is changed separately, and processing is performed at different positions of the test optical element 6. The numerical changes of the polishing gap and the magnetic field strength are recorded at the same time, and then the following is obtained in the conversion relationship module:

[0070] ;

[0071] in, Indicates polishing gap and magnetic field strength In this specific embodiment, specifically to control the polishing wheel 8 to perform fixed-point processing on the test optical element 6 at different polishing gaps with different magnetic field intensities for one end of the time;

[0072] A3: In the conversion relationship module, the first conversion relationship is calculated based on the third conversion relationship and the fourth conversion relationship:

[0073] ;

[0074] in, Indicates the first conversion relationship.

[0075] A4: Setting a force change threshold and maximum magnetic field strength; combining the first conversion relationship, the force change threshold, and the maximum magnetic field strength, controls the magnetorheological processing module to process the optical element 5 to be processed. During the processing, the real-time control module adjusts the magnetorheological processing module in real time. The force change threshold and maximum magnetic field strength are adaptively set based on actual conditions and are not limited in this embodiment. The specific process of step A4 is as follows:

[0076] Control the magnetorheological processing module to move to the current processing position When the current force measured by force sensor 3 is Force change threshold For comparison:

[0077] If the current force Less than the force change threshold ,Right now , not the current magnetic field strength Make adjustments;

[0078] If the current force Greater than or equal to the force change threshold ,Right now , for the current magnetic field strength Make adjustments:

[0079] If the current magnetic field strength Less than the maximum magnetic field strength ,Right now When the current magnetic field strength Adjust according to the following formula:

[0080] ;

[0081] If the current magnetic field strength Greater than or equal to the maximum magnetic field strength ,Right now When the current magnetic field strength Adjust to maximum magnetic field strength .

[0082] Specific embodiment 2: The magnetorheological polishing method based on electromagnet position adjustment provided in this specific embodiment, the magnetorheological polishing device based on force sensor adjustment of electromagnet according to the invention embodiment, combined with Figures 1 to 4 , including the following steps:

[0083] B1: Control the polishing wheel 8 to process the test optical element 6 with different polishing gaps, and use the force sensor 3 to record the force changes at each processing point. The conversion relationship module obtains:

[0084] ;

[0085] in, Expressive power Polishing gap In this specific embodiment, specifically for controlling the polishing wheel 8 to perform fixed-point processing on the test optical element 6 at one end of the time with different polishing gaps;

[0086] B2: Keeping the force constant, change the electromagnet position individually at different polishing gaps, and perform processing at different positions of the test optical element 6. Simultaneously record the numerical changes in the polishing gap and the electromagnet position, and obtain the following in the conversion relationship module:

[0087] ;

[0088] in, Indicates polishing gap With the electromagnet position In this specific embodiment, specifically to control the polishing wheel 8 to perform fixed-point processing of the test optical element 6 at different polishing gaps with different magnetic field intensities;

[0089] B3: In the conversion relationship module, the second conversion relationship is calculated based on the fifth conversion relationship and the sixth conversion relationship:

[0090] ;

[0091] in, Indicates the second conversion relationship.

[0092] B4: Setting the force change threshold and maximum electromagnet position; combining the second conversion relationship, the force change threshold, and the maximum electromagnet position, controls the magnetorheological processing module to process the optical element 5 to be processed. During the processing, the real-time control module adjusts the magnetorheological processing module in real time. The force change threshold and maximum electromagnet position are adaptively set based on actual conditions and are not limited in this embodiment. The specific process of step B4 is as follows:

[0093] Control the magnetorheological processing module to move to the current processing position When the current force measured by force sensor 3 is Force change threshold For comparison:

[0094] If the current force Less than the force change threshold ,Right now , incorrect current electromagnet position Make adjustments;

[0095] If the current force Greater than or equal to the force change threshold ,Right now , for the current electromagnet position Make adjustments:

[0096] If the current electromagnet position Less than the maximum solenoid position ,Right now When the current electromagnet position is Make adjustments:

[0097] ;

[0098] If the current electromagnet position Greater than or equal to the maximum electromagnet position ,Right now When the current electromagnet position Adjust to the maximum solenoid position .

[0099] Specific embodiment 3: The magnetorheological polishing method based on magnetic field strength and polishing wheel movement provided in this specific embodiment, the magnetorheological polishing device based on force sensor adjustment electromagnet according to the invention embodiment, combined with Figures 1 to 4 , including the following steps:

[0100] C1: Control the magnetorheological processing module to process 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 through the conversion relationship module during the processing. The specific process is as follows:

[0101] Keeping the position between the polishing wheel 8 and the electromagnet 7 unchanged, the polishing wheel 8 is controlled to process the test optical element 6 with different polishing gaps, and the force changes at each processing point are recorded by the force sensor 3. The conversion relationship module obtains:

[0102] ;

[0103] in, Expressive power Polishing gap In this embodiment, the polishing wheel 8 is controlled to perform fixed-point processing on the test optical element 6 at different polishing gaps for a period of time.

[0104] C2: Setting the force change threshold, maximum magnetic field strength, and maximum polishing gap; combining the seventh conversion relationship, the force change threshold, maximum magnetic field strength, and maximum polishing gap, controls the magnetorheological processing module to process the optical element 5 to be processed. During the processing, the real-time control module adjusts the magnetorheological processing module in real time. The force change threshold, maximum magnetic field strength, and maximum polishing gap are adaptively set according to actual conditions and are not limited in this embodiment. The specific process of step C2 is as follows:

[0105] Control the magnetorheological processing module to move to the current processing position When the current force measured by force sensor 3 is Force change threshold For comparison:

[0106] If the current force Less than the force change threshold ,Right now , not the current polishing gap Make adjustments;

[0107] If the current force Greater than or equal to the force change threshold ,Right now , for the current polishing gap Make adjustments:

[0108] If the current polishing gap Smaller than the maximum polishing gap , and the current magnetic field strength Less than the maximum magnetic field strength ,Right now and , current magnetic field strength and current polishing gap Adjust according to the following formula:

[0109] ;

[0110] ;

[0111] in, Indicates 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 the proportional coefficient;

[0112] If the current polishing gap Greater than or equal to the maximum polishing gap , and the current magnetic field strength Greater than or equal to the maximum magnetic field strength ,Right now and , the current polishing gap Adjust to maximum polishing gap , the current corresponding magnetic field strength Adjust to maximum magnetic field strength .

[0113] All transformation relationships in the above specific embodiments are obtained by fitting. The fitting process includes but is not limited to importing discrete data into Matlab software, using Matlab's polyfit fitting command to complete data fitting, and solving the respective transformation relationships. Polyfit fitting command is a basic general command of Matlab software. This method can more intuitively see the corresponding relationship between correlations and the corresponding function curve.

[0114] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0115] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A magnetorheological polishing device based on a force sensor to adjust an electromagnet, comprising a robot and a control unit, characterized in that: The robot further comprises a magnetorheological processing module and a force sensor; wherein: the magnetorheological processing module is connected to the free end of the robot via the force sensor; the robot drives the magnetorheological processing module to process the optical element, and during the processing, the force sensor measures the processing force applied by the magnetorheological processing module to the optical element; The magnetorheological processing module includes a real-time adjustment device and a magnetorheological mounting frame, wherein the magnetorheological mounting frame is connected to the force sensor, the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, 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 electromagnet is connected to the real-time adjustment device, and the electromagnet is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the electromagnet and changes the stiffness of the magnetorheological fluid; at the same time, the real-time adjustment device adjusts the magnetic field strength and the distance between the electromagnet and the polishing wheel; The real-time adjustment device includes a displacement output motor, a lead screw, a support and fixing frame, and a current intensity controller; the support and fixing frame is arranged on the magnetorheological mounting frame; the displacement output motor is arranged on the support and fixing frame and is connected to the lead screw arranged on the support and 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 and fixing frame 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 strength of the electromagnet; The interior of the control unit includes: a conversion relationship module for obtaining a first conversion relationship based on the magnetic field strength of the electromagnet in the magnetorheological processing module and the force value collected by the force sensor, and obtaining a second conversion relationship based on the electromagnet position of the electromagnet and the force value, during the process of controlling the magnetorheological processing module to test the test optical element; the conversion relationship module further comprising obtaining a seventh conversion relationship based on the polishing gap during the processing of the magnetorheological processing module and the force value collected by the force sensor; a real-time control module, configured to adjust the magnetic field intensity in combination with the first conversion relationship, or adjust the electromagnet position in combination with the second conversion relationship, during the process of controlling the magnetorheological processing module to process the optical element to be processed, so as to stabilize the removal function during the process of processing the optical element; The process of adjusting the magnetic field strength in combination with the first conversion relationship is as follows: 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 set force change threshold: if the current force is less than the force change threshold, the current magnetic field strength is not adjusted; if the current force is greater than or equal to the force change threshold, the current magnetic field strength is adjusted: If the current magnetic field strength is less than the set maximum magnetic field strength, the magnetic field strength corresponding to the current force is obtained using the first conversion relationship, and the current magnetic field strength is adjusted to the obtained magnetic field strength; 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; The process of adjusting the position of the electromagnet in combination with the second conversion relationship is as follows: 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 set force change threshold: if the current force is less than the force change threshold, the current electromagnet position is not adjusted; if the current force is greater than or equal to the force change threshold, the current electromagnet position is adjusted: If the current electromagnet position is less than the set maximum electromagnet position, the electromagnet position corresponding to the current force is obtained using the second conversion relationship, and the current electromagnet position is adjusted to the obtained electromagnet position; if the current electromagnet position is greater than or equal to the maximum electromagnet position, the current electromagnet position is adjusted to the maximum electromagnet position; The real-time control module is further configured to adjust the polishing gap and the corresponding magnetic field strength in combination with the seventh conversion relationship during the process of controlling the magnetorheological processing module to process the optical element to be processed, wherein the process is as follows: When controlling the magnetorheological machining module to move to the current machining position, the current force measured by the force sensor is compared with the set force change threshold: if the current force is less than the force change threshold, the current polishing gap is not adjusted; if the current force is greater than or equal to the force change threshold, the current polishing gap is adjusted: If the current polishing gap is smaller than the set maximum polishing gap, and the current magnetic field strength is smaller than the set maximum magnetic field strength, the polishing gap corresponding to the current force is obtained using the seventh conversion relationship, and the corresponding magnetic field strength is obtained based on the relationship between the magnetic field strength and the polishing gap; 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, the current polishing gap is adjusted to the maximum polishing gap, and the current corresponding magnetic field strength is adjusted to the maximum magnetic field strength.

2. The magnetorheological polishing device based on force sensor adjustment of electromagnet according to claim 1, characterized in that: The magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle and a supply system; wherein, The polishing motor is connected to the polishing wheel via the transmission belt, so that the polishing motor controls the polishing wheel to rotate, thereby causing the polishing wheel to process the optical element; The nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the supply system transports magnetorheological fluid to the nozzle.

3. The magnetorheological polishing device based on force sensor-adjusted electromagnet according to claim 1, characterized in that: The force sensor, the robot and the displacement output motor are respectively connected to the control unit to form respective communication lines, and the control unit receives and sends signals through the corresponding communication lines.

4. A magnetorheological polishing method based on magnetic field strength, based on the magnetorheological polishing device based on force sensor-adjusted electromagnet according to any one of claims 1 to 3, characterized in that: The following steps are involved: A1: Controlling the polishing wheel to process the test optical element with different polishing gaps, and recording the force changes at each processing point by the force sensor, and obtaining a third conversion relationship between the force and the polishing gap in the conversion relationship module; A2: Under different polishing gaps, the magnetic field strength is individually changed, and processing is performed at different positions of the test optical element, and a fourth conversion relationship between the polishing gap and the magnetic field strength is obtained in the conversion relationship module; A3: In the conversion relationship module, the first conversion relationship is calculated based on the third conversion relationship and the fourth conversion relationship; A4: Setting a force change threshold and a maximum magnetic field strength; controlling the magnetorheological processing module to process the optical element to be processed in combination with the first conversion relationship, the force change threshold, and the maximum magnetic field strength, and during the processing, the real-time control module adjusts the magnetorheological processing module in real time; In step A4, the magnetorheological processing module is controlled to move to the current processing position. When the current force measured by the force sensor Force change threshold For comparison: If the current force Less than the force change threshold , not the current magnetic field strength Make adjustments; If the current force Greater than or equal to the force change threshold , for the current magnetic field strength Make adjustments: If the current magnetic field strength Less than the maximum magnetic field strength , for the current magnetic field strength Adjust according to the following formula: ； in, represents the first conversion relationship; If the current magnetic field strength Greater than or equal to the maximum magnetic field strength , the current magnetic field strength Adjust to maximum magnetic field strength .

5. A magnetorheological polishing method based on electromagnet position adjustment, based on the magnetorheological polishing device based on force sensor adjustment of electromagnet according to any one of claims 1 to 3, characterized in that: The following steps are involved: B1: Controlling the polishing wheel to process the test optical element with different polishing gaps, and recording the force changes at each processing point by the force sensor, and obtaining a fifth conversion relationship between the force and the polishing gap in the conversion relationship module; B2: Under different polishing gaps, the positions of the electromagnets are individually changed, and processing is performed at different positions of the test optical element, and a sixth conversion relationship between the polishing gaps and the positions of the electromagnets is obtained in the conversion relationship module; B3: In the conversion relationship module, the second conversion relationship is calculated based on the fifth conversion relationship and the sixth conversion relationship; B4: Setting a force change threshold and a maximum electromagnet position; controlling the magnetorheological processing module to process the optical element to be processed by combining the second conversion relationship, the force change threshold and the maximum electromagnet position, and adjusting the magnetorheological processing module in real time during the processing; In step B4, the magnetorheological processing module is controlled to move to the current processing position. When the current force measured by the force sensor Force change threshold For comparison: If the current force Less than the force change threshold , incorrect current electromagnet position Make adjustments; If the current force Greater than or equal to the force change threshold , for the current electromagnet position Make adjustments: If the current electromagnet position Less than the maximum solenoid position , according to the following formula, the current electromagnet position Make adjustments: ； in, represents the second conversion relationship; If the current electromagnet position Greater than or equal to the maximum electromagnet position , the current electromagnet position Adjust to the maximum solenoid position .

6. A magnetorheological polishing method based on magnetic field strength and polishing wheel movement, based on the magnetorheological polishing device based on force sensor-adjusted electromagnet according to any one of claims 1 to 3, characterized in that: The following steps are involved: C1: controlling the magnetorheological processing module to process the test optical element, and obtaining, through the conversion relationship module, a seventh conversion relationship between the polishing gap of the polishing wheel and the force value measured by the force sensor during the processing; C2: Setting a force change threshold, a maximum magnetic field strength, and a maximum polishing gap; controlling the magnetorheological processing module to process the optical element to be processed by combining the seventh conversion relationship, the force change threshold, the maximum magnetic field strength, and the maximum polishing gap, and during the processing, the real-time control module makes real-time adjustments to the magnetorheological processing module; In step C2, the magnetorheological processing module is controlled to move to the current processing position. When the current force measured by the force sensor Force change threshold For comparison: If the current force Less than the force change threshold , not the current polishing gap Make adjustments; If the current force Greater than or equal to the force change threshold , for the current polishing gap Make adjustments: If the current polishing gap Smaller than the maximum polishing gap , and the current magnetic field strength Less than the maximum magnetic field strength , current magnetic field strength and current polishing gap Adjust according to the following formula: ； ； in, 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 the proportional coefficient; If the current polishing gap Greater than or equal to the maximum polishing gap , and the current magnetic field strength Greater than or equal to the maximum magnetic field strength , the current polishing gap Adjust to maximum polishing gap , current magnetic field strength Corresponding adjustment to the maximum magnetic field strength .

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