Magnetorheological machining device and method based on motor current to adjust machining speed

Abstract

The present invention relates to the field of magnetorheological technology, and specifically to a magnetorheological processing device and method for adjusting the processing speed based on motor current. The device includes a polishing component, a moving component and a control unit. When the polishing module polishes the component to be polished, it collects the first instantaneous current corresponding to different processing speeds, calculates the corresponding relationship between the processing speed and the ideal motor current, and then judges the second instantaneous current data based on this. According to the judgment result, it is decided whether to adjust the processing speed. This process does not require the calibration step of parameters such as gravity compensation. The accuracy of the measurement data is only limited by the current measurement accuracy of the second instantaneous current data. The measurement result is more accurate, which reduces the equipment cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetorheological machining, and in particular relates to a magnetorheological machining device and method for adjusting machining speed based on motor current. Background Art

[0002] Magnetorheological finishing (MRF) is an advanced optical manufacturing technology that has developed in recent years. It offers 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 machining centers primarily integrate polishing modules onto CNC machine tools. However, CNC machine tools have limitations (such as low degrees of freedom, large footprint, and high cost) that limit the deviation of aspheric surfaces and hinder precise position control along the surface normal. 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 polishing module is integrated into the industrial robot, theoretically, high-precision processing of large-aperture complex curved optical components can be achieved. However, due to the influence of factors such as processing, assembly, load, trajectory planning, and reduction ratio, the robot end execution accuracy is low, and the polishing gap changes greatly during the processing. At the same time, magnetorheological polishing technology is an optical processing technology with high certainty 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 cannot meet the requirements of magnetorheological polishing technology for polishing gap changes during high-precision polishing.

[0003] Force-position control is currently gaining popularity as a new approach to robotic constant-force controlled polishing. A common application involves placing a force sensor between the machining tool and the robot. The force sensor is first calibrated with gravity to ensure measurement accuracy. The position error is calculated by measuring force changes. This position error is then compensated for using the robot itself or other motion compensation mechanisms to achieve constant force control. Efficient machining of large-aperture optical components requires magnetorheological (MR) machining equipment with large polishing wheels. These MR machining modules typically weigh hundreds of kilograms. However, for these MR machining modules, the force variation caused by the robot's position error is only tens of Newtons. High-precision machining requires maintaining a constant force of a few Newtons or even a fraction of a Newton. This requires measurement equipment such as force sensors to achieve an absolute accuracy of one part per ten thousand. Furthermore, the force sensor must be capable of varying speed and position. Force sensors that meet these requirements are often extremely expensive, significantly increasing the cost of the equipment. Summary of the Invention

[0004] In view of this, the present invention aims to provide a magnetorheological processing device and method for adjusting the processing speed based on motor current, so as to adjust the processing speed in real time by sensing the motor current, thereby solving the problem that the existing technology requires the use of high-precision force sensors for data collection for the control of the polishing wheel, and the high cost of high-precision force sensors.

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

[0006] A magnetorheological machining device for adjusting machining speed based on motor current, comprising:

[0007] The polishing assembly includes a drive motor and a polishing module, wherein the drive motor is used to drive the polishing module to move;

[0008] A moving assembly, rigidly connected to the polishing assembly, for driving the polishing assembly to move to the location of the component to be polished;

[0009] A control unit controls the polishing module to perform fixed-point processing on the polishing element at different processing speeds, collects the instantaneous current of the drive motor in real time, and adjusts the processing speed according to the instantaneous current;

[0010] The processing rotation speed includes the polishing wheel rotation speed of the polishing wheel in the polishing module and the liquid pump rotation speed of the liquid pump.

[0011] Furthermore, in the control unit:

[0012] Calculating a correspondence between a machining speed and a set ideal motor current based on first polishing data, the first polishing data including first instantaneous current data of a driving motor at the set machining speed; and collecting second instantaneous current data in real time, and comparing the second instantaneous current data with the ideal motor current corresponding to the current machining speed in the correspondence. If a difference between the second instantaneous current data and the ideal motor current exceeds a preset error range, controlling the polishing assembly to adjust the current machining speed so that the difference between the second instantaneous current data collected after the machining speed adjustment and the ideal motor current is within the preset error range.

[0013] The second instantaneous current data is the current data of the driving motor collected in real time by the control unit when the driving motor drives the polishing module to polish the component to be polished at a constant speed.

[0014] Furthermore, the polishing module includes:

[0015] The magnetorheological mounting frame is connected to the moving assembly; the driving motor is arranged on the magnetorheological mounting frame, and the polishing wheel is arranged on the magnetorheological mounting frame; the driving motor drives the polishing wheel to rotate and adjusts the polishing wheel speed;

[0016] a magnet, disposed on the magnetorheological mounting frame and close to the working point of the polishing wheel;

[0017] A magnetorheological medium is connected to the polishing wheel. The magnetorheological medium is driven by the polishing wheel to enter the magnetic field working area of ​​the magnet to form a magnetorheological ribbon. The magnetorheological ribbon size parameters change with the polishing gap and magnetic field strength, and is used to polish the component to be polished.

[0018] The nozzle is arranged on the magnetorheological mounting frame through the nozzle mounting seat. The liquid pump conveys magnetorheological fluid medium to the nozzle, and the nozzle provides magnetorheological fluid medium to the polishing wheel.

[0019] A magnetorheological machining method for adjusting the polishing wheel speed based on motor current, according to the present invention, is provided with a magnetorheological machining device for adjusting the machining speed based on motor current, the method comprising the following steps:

[0020] The moving assembly drives the polishing assembly to move to the location of the test optical element, and makes the polishing module contact with the test optical element;

[0021] The control unit calculates a correspondence between a polishing wheel speed and an ideal motor current based on first polishing data, the first polishing data including real-time current data of the drive motor collected at different polishing wheel speed settings; and collects second instantaneous current data in real time, and compares the second instantaneous current data with the ideal motor current corresponding to the current polishing wheel speed in the correspondence. If a difference between the second instantaneous current data and the ideal motor current exceeds a preset error range, the control unit controls the drive motor to adjust the current polishing wheel speed so that the difference between the adjusted second instantaneous current data and the ideal motor current is within the preset error range.

[0022] The second instantaneous current data is the current data of the driving motor collected in real time by the control unit when the driving motor drives the polishing module to polish the component to be polished at a constant speed.

[0023] Furthermore, if the sampling period for collecting the second instantaneous current data is recorded as t1, the shortest time required for the polishing wheel speed to complete the set maximum change adjustment amount is recorded as t2, and the shortest switching time between two adjacent track points to be processed on the component to be polished is recorded as t3;

[0024] Methods include:

[0025] Determine whether the relationship between t1, t2, and t3 satisfies the formula:

[0026] ;

[0027] If it is not satisfied, the sampling frequency of the control unit for collecting the second instantaneous current data is adjusted until the above formula is satisfied, and the sampling frequency is 1 / t1.

[0028] Furthermore, the maximum change adjustment amount is the adjustment range corresponding to the upper threshold or lower threshold of the preset error range from the set ideal polishing wheel speed, which is recorded as ΔV 1max ;

[0029] t2=ΔV 1max / dV1,t3=ΔL / V max , where dV1 is the fastest adjustment rate of the polishing wheel speed, V max is the maximum moving speed of the moving component, and ΔL represents the distance between two adjacent points on the track to be processed on the component to be polished.

[0030] Furthermore, the method further comprises:

[0031] When the moving assembly drives the polishing module to move from the first track point to the second track point, filtering the second instantaneous current data collected by the control unit during the movement, and comparing the filtered second instantaneous current data with the ideal motor current under the current polishing gap;

[0032] If the number of second instantaneous current data collected by the control unit during the movement is recorded as a, then a satisfies the following formula:

[0033] .

[0034] Furthermore, if the current polishing wheel speed V i The adjustment range to the upper threshold of the preset error range is recorded as +ΔV 1max , the corresponding current output value of the drive motor is A0+ΔA max , A0 represents the ideal motor current, ΔA max Indicates the corresponding current adjustment amplitude;

[0035] The polishing wheel speed V i The adjustment range to the lower limit of the preset error range is recorded as -ΔV 1max , the corresponding current output value of the drive motor is A0-ΔA max ;

[0036] Control the driving motor to the current polishing wheel speed V i Adjustments include:

[0037] If the current second instantaneous current data A i Does not exceed the permissible range of variation [A ′ ,A ′′ ], there is no need to control the drive motor to the current polishing wheel speed V i Make adjustments;

[0038] If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |<|A0±ΔA max |, then the drive motor is controlled according to the corresponding relationship F va The current polishing wheel speed V i Adjust according to the following formula:

[0039] ;

[0040] If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |≥|A0±ΔA max |, then the current polishing wheel speed V i Adjust to V0±ΔV 1max, V0 represents the initially set polishing wheel speed; the second instantaneous current data A corresponding to the adjusted polishing wheel speed i Return to the permissible range of variation [A ′ ,A ′′ ]middle.

[0041] A magnetorheological machining method for adjusting the speed of a liquid pump based on motor current, according to the present invention, is provided with a magnetorheological machining device for adjusting the machining speed based on motor current, the method comprising the following steps:

[0042] The moving assembly drives the polishing assembly to move to the location of the test optical element, and makes the polishing module contact with the test optical element;

[0043] The control unit calculates a correspondence between a liquid pump speed and an ideal motor current based on first polishing data, the first polishing data including real-time current data of the drive motor collected at different liquid pump speed settings; and collects second instantaneous current data in real time, and compares the second instantaneous current data with the ideal motor current corresponding to the current liquid pump speed in the correspondence. If a difference between the second instantaneous current data and the ideal motor current in the correspondence exceeds a preset error range, the control unit controls the polishing module to adjust the current liquid pump speed so that the difference between the adjusted second instantaneous current data and the ideal motor current is within the preset error range.

[0044] The second instantaneous current data is the current data of the driving motor collected in real time by the control unit when the driving motor drives the polishing module to polish the component to be polished at a constant speed.

[0045] Furthermore, if the sampling period for collecting the second instantaneous current data is recorded as t1, the shortest time required for the liquid pump speed to complete the set maximum change adjustment amount is recorded as t2, and the shortest switching time between two adjacent track points to be processed on the component to be polished is recorded as t3;

[0046] Methods include:

[0047] Determine whether the relationship between t1, t2, and t3 satisfies the following formula:

[0048] ;

[0049] If not, the sampling frequency of the control unit for collecting the second instantaneous current data is adjusted until the above formula is satisfied, and the sampling frequency is set to 1 / t1.

[0050] Furthermore, the maximum change adjustment amount is the adjustment range corresponding to the upper threshold or lower threshold of the preset error range from the set ideal liquid pump speed, which is recorded as ΔSV max ;

[0051] t2=ΔSV max / SV max , t3=ΔL / V max , where SV max is the maximum speed adjustment rate of the liquid pump, V max is the maximum moving speed of the moving component, and ΔL represents the distance between two adjacent points on the track to be processed on the component to be polished.

[0052] Furthermore, the method further comprises:

[0053] When the moving assembly drives the polishing module to move from the first track point to the second track point, filtering the second instantaneous current data collected by the control unit during the movement, and comparing the filtered second instantaneous current data with the ideal motor current under the current polishing gap;

[0054] If the number of second instantaneous current data collected by the control unit during the movement is recorded as a, then a satisfies the following formula:

[0055] .

[0056] Furthermore, if the current liquid pump speed SV i The adjustment range to the upper threshold of the preset error range is recorded as +ΔSV max , the corresponding current output value of the drive motor is A0+ΔA max , A0 represents the ideal motor current, ΔA max Indicates the corresponding current adjustment amplitude;

[0057] The current liquid pump speed SV i The adjustment range to the lower limit threshold of the preset error range is recorded as -ΔSV max , the corresponding current output value of the drive motor is A0-ΔA max ;

[0058] Control the polishing module to the current liquid pump speed SV i Adjustments include:

[0059] If the current second instantaneous current data A i Does not exceed the permissible range of variation [A ′ ,A ′′ ], there is no need to control the polishing module to the current liquid pump speed SV i Make adjustments;

[0060] If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |<|A0±ΔA max|, then the control polishing module combines the corresponding relationship F sa Current liquid pump speed SV i Adjust according to the following formula:

[0061] ;

[0062] If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |≥|A0±ΔA max |, then the current liquid pump speed SV i Adjusted to SV0±ΔSV max SV0 represents the initially set liquid pump speed; the second instantaneous current data A corresponding to the adjusted liquid pump speed i Return to the permissible range of variation [A ′ ,A ′′ ]middle.

[0063] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0064] The magnetorheological processing device and method for adjusting the processing speed based on motor current created by the present invention utilizes the relationship between the polishing module and the motor current. When the polishing module polishes the polishing element, different processing speeds and their corresponding first instantaneous current data are collected respectively and their respective corresponding relationships are obtained. The second instantaneous current data is then judged based on these corresponding relationships, and whether to adjust the processing speed is determined based on the judgment result. This process does not require calibration steps for parameters such as gravity compensation, and will not be affected by the weight of the magnetorheological processing module of the robotic magnetorheological processing equipment, the equipment's own operating accuracy, operating speed, posture, inertia and other factors. The accuracy of the measurement data is only limited by the current measurement accuracy of the second instantaneous current data. The measurement results are more accurate, and there is no need to add high-precision force sensors and other equipment, thereby reducing equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] 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:

[0066] Figure 1 A schematic structural diagram of a magnetorheological machining device for adjusting machining speed based on motor current according to an embodiment of the present invention, viewed from one perspective;

[0067] Figure 2A schematic structural diagram of a magnetorheological machining device for adjusting machining speed based on motor current according to an embodiment of the present invention from another perspective;

[0068] Figure 3 This is a schematic structural diagram of a liquid pump according to an embodiment of the present invention.

[0069] Description of reference numerals:

[0070] 1. Polishing platform; 2. Component to be polished; 3. Polishing module; 4. Drive motor; 5. Control unit; 6. Moving assembly; 7. Polishing wheel; 8. Liquid pump; 9. Magnetorheological mounting bracket; 10. Transmission belt; 11. Nozzle; 12. Magnet; 13. Mounting bracket; 14. Liquid pump body; 15. Cooling chamber; 16. Magnetorheological fluid storage chamber; 17. Cooling water inlet; 18. Magnetorheological fluid inlet; 19. Cooling water outlet; 20. Magnetorheological fluid outlet. DETAILED DESCRIPTION

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0076] like Figures 1 to 2 As shown, the magnetorheological machining device for adjusting the machining speed based on motor current according to the embodiment of the present invention includes a polishing platform 1, a polishing assembly, a moving assembly 6, and a control unit 5. The polishing platform 1 is provided with an element 2 to be polished; the polishing assembly includes a polishing module 3 and a drive motor 4. The polishing module 3 is used to perform a polishing process on the element 2 to be polished, and the drive motor 4 is used to drive the polishing module 3 to move; the moving assembly 6 is rigidly connected to the polishing assembly and is used to drive the polishing assembly to the position of the element 2 to be polished, and is used to adjust the polishing gap between the polishing module 3 and the element 2 to be polished, as well as the working position of the polishing assembly; the control unit 5 controls the polishing module 3 to perform fixed-point machining on the element 2 to be polished at different machining speeds, and collects the instantaneous current of the drive motor 4 in real time, and adjusts the machining speed according to the instantaneous current. Specifically, the machining speed includes the polishing wheel speed of the polishing wheel 7 in the polishing module 3 and the liquid pump speed of the liquid pump 8.

[0077] In this embodiment, the polishing platform 1 refers to a working platform for experiments, on which are placed the component to be polished 2, a test optical element for experimental processing, and other polishing components, such as the magnetorheological medium required for polishing, supporting tooling for the component to be polished 2, etc., wherein the component to be polished 2 is a component that requires magnetorheological polishing processing.

[0078] In this embodiment, the polishing module 3 includes a magnetorheological mounting frame 9 , a nozzle 11 and a magnet 12 . The magnetorheological mounting frame 9 is rigidly connected to the moving assembly 6, and the drive motor 4 is mounted on the magnetorheological mounting frame 9. The polishing wheel 7 is mounted on the magnetorheological mounting frame 9. The output end of the drive motor 4 is connected to the bearing of the polishing wheel 7 via a transmission belt 10, so that the drive motor 4 controls the rotation of the polishing wheel 7. A magnet 12 is mounted on the magnetorheological mounting frame 9 and is close to the working point of the polishing wheel 7 (in this embodiment of the present invention, the working point of the polishing wheel 7 is defined as the point of closest approach between the polishing wheel 7 and the surface of the component 2 to be polished, along the normal direction of the surface of the component 2 to be polished). A liquid pump 8 is mounted on one side of the polishing platform 1 via a mounting frame 13. The liquid pump 8 delivers magnetorheological medium to a nozzle 11. The nozzle 11 is mounted on the magnetorheological mounting frame 9 along the direction of rotation of the polishing wheel 7 and is connected to the polishing wheel 7 via the magnetorheological medium. The magnetorheological medium is driven by the polishing wheel 7 to enter the magnetic field working area of ​​the magnet 12 to form a magnetorheological ribbon. The size parameters of the magnetorheological ribbon vary with the polishing gap and magnetic field strength, and are used to polish the component 2 to be polished.

[0079] The entirety of the liquid pump 8 is as follows Figure 3 As shown, the pump body 14 comprises a liquid pump, a cooling chamber 15, and a magnetorheological fluid storage chamber 16. In this embodiment of the present invention, the liquid pump body 14 utilizes a DFLD vertical multi-stage pump from Shanghai Dongfang Pump Industry Co., Ltd. The pump body 14 is used to supply magnetorheological fluid; the cooling chamber 15 is primarily used to store cooling water and cool the magnetorheological fluid; and the magnetorheological fluid storage chamber 16 is primarily used to store the magnetorheological fluid. When the liquid pump 8 is operating, cooling water enters the cooling chamber 15 through the cooling water inlet 17, and magnetorheological fluid flows from the magnetorheological fluid inlet 18 through the magnetorheological fluid storage chamber 16 into the pump body 14. After cooling the magnetorheological fluid in the cooling chamber 15, the cooling water is discharged from the cooling water outlet 19. The cooled magnetorheological fluid is then discharged from the magnetorheological fluid outlet 20 and delivered to the nozzle 11 via a pipeline. The speed of the liquid pump body 14, i.e., the liquid pump speed, is regulated by a motor.

[0080] The motors of the drive motor 4, moving assembly 6, and liquid pump 8 are each connected to the control unit 5 to form their own communication circuits, enabling the control unit 5 to receive and send signals via the corresponding communication circuits. During operation, the control unit 5 sends control commands to the drive motor 4, which adjusts the polishing wheel 7's speed. The control unit 5 also sends control commands to the motor of the liquid pump 8, which adjusts its speed in real time, thereby regulating the liquid flow rate. Because the polishing wheel 7 generates a strong magnetic field during polishing, the communication circuits are routed away from these strong magnetic fields to prevent the wires from being attracted to the polishing module 3 and impacting normal operation.

[0081] The moving component 6 can be a robotic arm or other robot with posture adjustment function; optionally, the moving component 6 is a six-axis robotic arm, the driving motor 4 and the robotic arm are rigidly connected by metal hardware, and the robotic arm drives the polishing component to complete the processing of the entire component 2 to be polished.

[0082] When the processing speed in polishing module 3 changes, the shear force between the polished component 2 and the magnetorheological medium in polishing module 3 changes. To maintain a constant polishing speed, the current of drive motor 4 will eventually change accordingly. The change in processing speed is calculated by measuring the change in current of drive motor 4.

[0083] In this embodiment, the control unit 5 is configured to obtain first polishing data based on the current of the drive motor 4 at different processing speeds (i.e., polishing wheel speed or liquid pump speed) when the drive motor 4 drives the polishing module 3 to perform fixed-point polishing on the test optical element, and calculate the corresponding relationship between the processing speed and the ideal motor current based on the first polishing data. The first polishing data includes first instantaneous current data of the drive motor 4 at different processing speeds, and the different processing speeds can be preset.

[0084] The first polishing data can be collected multiple times, and finally the error between multiple sets of first polishing data can be reduced by numerical calculation methods such as taking the mean or variance, and then the relationship between the ideal motor current and the processing speed can be calculated based on the first polishing data.

[0085] In this embodiment, the control unit 5 calculates the correspondence between different machining speeds and the ideal motor current by correlating the first instantaneous current data with the corresponding machining speed. Using this as a reference, when polishing the component 2 to be polished, the control unit 5 compares the second instantaneous current data corresponding to different polishing regions of the component 2 to see if the difference between the ideal motor current and the current second instantaneous current data is within a preset error range. If not, the machining speed is adjusted to ensure that the current second instantaneous current data is equal to, or within the same preset error range as, the ideal motor current corresponding to the current machining speed. This approach enables real-time adjustment of the machining speed based on the correspondence between the machining speed and the instantaneous current.

[0086] By utilizing the relationship between the polishing module 3 and the motor current, when the polishing module 3 polishes the test optical element, different processing speeds and the corresponding first instantaneous current data are collected, and then the corresponding relationship between the processing speed and the ideal motor current is calculated through the collected processing speed and the first instantaneous current data. Then, the second instantaneous current data is judged by this relationship, and it is decided whether to adjust the processing speed of the polishing element 2 according to the judgment result. This process does not require calibration steps of parameters such as gravity compensation, and will not be affected by the weight of the magnetorheological processing module of the robot magnetorheological processing equipment, the equipment's own operating accuracy, operating speed, posture, inertia and other factors. The accuracy of the measurement data is only limited by the current measurement accuracy of the second instantaneous current data. The measurement results are more accurate, and there is no need to add high-precision force sensors and other equipment, thereby reducing equipment costs.

[0087] The polishing principle is as follows: When the polishing wheel 7 is polishing, the magnetorheological medium is affected by the magnetic field and changes from a liquid state to a solid-like state, forming a Bingham fluid. As the polishing wheel 7 rotates, the Bingham fluid applies a shear force to the outer surface of the element to be polished 2, thereby polishing the element to be polished 2. Different processing speeds correspond to different shear forces, and therefore, different processing speeds achieve different polishing effects. When the processing speed changes, the thickness of the magnetorheological ribbon of the magnetorheological medium placed in the polishing area changes, causing the shear force between the element to be polished 2 and the magnetorheological ribbon to change. In order to maintain a constant speed, the polishing wheel 7 will eventually cause the current of the drive motor 4 to change accordingly. The corresponding relationship can be expressed by the following formula:

[0088] ;

[0089] Where n represents the polishing wheel speed, k represents the proportional coefficient, U represents the voltage of drive motor 4, F represents the force (i.e., shear force) acting on drive motor 4, r represents the torque (i.e., the lateral distance from the lowest point of the polishing wheel to drive motor 4), and I represents the current of drive motor 4. By measuring the change in the current of drive motor 4, the change in the thickness of the magnetorheological ribbon in the polishing area is obtained, and the change in the current operating speed is then calculated. Finally, the polishing module 3 realizes real-time control of the operating speed change.

[0090] Based on the magnetorheological processing device for adjusting the processing speed based on motor current described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological processing method for adjusting the processing speed based on motor current, including a magnetorheological processing method for adjusting the polishing wheel speed based on motor current, and a magnetorheological processing method for adjusting the liquid pump speed based on motor current.

[0091] Example 1: A magnetorheological machining method based on motor current to adjust the polishing wheel speed, according to the magnetorheological machining device based on motor current to adjust the machining speed provided by the embodiment of the present invention, combined with Figure 1~Figure 2 , the method comprises the following steps:

[0092] The moving assembly 6 drives the polishing assembly to move to the location of the test optical element, and makes the polishing module 3 contact with the test optical element;

[0093] The control unit 5 calculates a correspondence between the polishing wheel speed and the ideal motor current based on the first polishing data, the first polishing data including real-time current data of the drive motor 4 collected at different set polishing wheel speeds; and collects second instantaneous current data in real time, and compares the second instantaneous current data with the ideal motor current corresponding to the current polishing wheel speed in the correspondence. If the difference between the second instantaneous current data and the ideal motor current exceeds a preset error range, the control unit 5 controls the drive motor 4 to adjust the current polishing wheel speed so that the difference between the adjusted second instantaneous current data and the ideal motor current is within the preset error range.

[0094] The second instantaneous current data is the current data of the driving motor 4 collected in real time by the control unit 5 when the driving motor 4 drives the polishing module 3 at a constant speed to polish the component to be polished.

[0095] In this embodiment, it is necessary to first obtain the corresponding relationship between the ideal motor current and the polishing wheel speed. The moving component 6 drives the polishing module 3 to move to the position of the test optical element and contacts the test optical element. In this process, the contact between the test optical element and the polishing module 3 means that the polishing wheel contacts the outer surface of the test optical element through the magnetorheological medium, and the part where the polishing module 3 contacts the test optical element is recorded as the first processing point. During the measurement of the same set of first polishing data, the first processing point remains unchanged. Optionally, when measuring multiple sets of first polishing data, different first processing points can be selected on the test optical element to facilitate improving the accuracy of the corresponding relationship between the ideal motor current and the polishing wheel speed.

[0096] During the process of polishing the test optical element by the polishing module 3, the control unit 5 controls the driving motor 4 to set different polishing wheel speeds, collects the first instantaneous current data corresponding to different polishing wheel speeds, maps and stores multiple sets of first instantaneous current data with the corresponding polishing wheel speeds, and obtains the first polishing data. The control unit 5 calculates the corresponding relationship between the polishing wheel speed and the ideal motor current based on the first polishing data.

[0097] After obtaining the correspondence between the ideal motor current and the polishing wheel speed, the polishing wheel speed of the polishing area of ​​the polishing element 2 can be adjusted according to this correspondence. After adjustment, the second instantaneous current data corresponding to the current polishing wheel speed of the polishing element 2 is placed within the same preset error range as the ideal motor current.

[0098] By utilizing the relationship between the polishing module 3 and the motor current, when the polishing module 3 polishes the polishing element 2, different polishing wheel speeds and the corresponding first instantaneous current data are collected respectively, and then the corresponding relationship between the polishing wheel speed and the ideal motor current is calculated by the collected polishing wheel speed and the first instantaneous current data. Thereafter, the second instantaneous current data is judged by this relationship, and it is decided whether to adjust the polishing wheel speed of the polishing element 2 according to the judgment result, so that the polishing wheel speed is adjusted in real time by using the drive motor 4. This process does not require the calibration steps of parameters such as gravity compensation, and will not be affected by the weight of the magnetorheological processing module of the robot magnetorheological processing equipment, the equipment's own operating accuracy, operating speed, posture, inertia and other factors. The accuracy of the measurement data is only limited by the current measurement accuracy of the second instantaneous current data. The measurement result is more accurate, and there is no need to add high-precision force sensors and other equipment, thereby reducing the equipment cost.

[0099] In some embodiments, the corresponding relationship between the polishing wheel speed and the ideal motor current is a function curve relationship, and the function curve relationship is fitted according to the discrete values ​​of the polishing wheel speed V and the first instantaneous current data A to obtain the corresponding relationship F va for:

[0100] .

[0101] In this embodiment, a plurality of polishing wheel rotational speeds V correspond to a plurality of first instantaneous current data A. Both the polishing wheel rotational speed V and the first instantaneous current data A are discrete values. Therefore, the discrete values ​​need to be fitted.

[0102] Fitting process: The discrete data is imported into Matlab software, and the data is fitted using the polyfit command in Matlab to determine the correspondence between the polishing wheel speed and the ideal motor current parameters. The Polyfit command is a basic general command in Matlab software. Ultimately, the correspondence between the polishing wheel speed and the ideal motor current is obtained. In this embodiment, the correspondence between the polishing wheel speed and the ideal motor current is a functional relationship.

[0103] In this way, the corresponding relationship between the ideal motor current and the polishing wheel speed can be more intuitively seen. Based on this, multiple components 2 to be polished under the same polishing conditions can be polished.

[0104] In some embodiments, if the sampling period for collecting the second instantaneous current data is recorded as t1, the shortest time required for the polishing wheel speed to complete the set maximum change adjustment amount is recorded as t2, and the shortest switching time between two adjacent to-be-processed trajectory points on the component to be polished 2 is recorded as t3;

[0105] Methods include:

[0106] Determine whether the relationship between t1, t2, and t3 satisfies the formula:

[0107] ;

[0108] If not, the sampling frequency of the control unit for collecting the second instantaneous current data is adjusted until the above formula is satisfied, and the sampling frequency is 1 / t1.

[0109] In this embodiment, the above formula gives the corresponding relationship between the three time elements, namely: within a single sampling period, the moving component 6 can adjust the polishing module 3 so that it moves to the polishing wheel speed corresponding to the ideal motor current, and then performs the next sampling, so as to avoid the sampling period being too long resulting in the sampling frequency being too slow, so that the sampling frequency and the adjustment speed of the polishing wheel speed do not match, and the adjustment is not timely, resulting in the inability to know the current state of the second instantaneous current data, affecting the automatic compensation function of the polishing wheel speed.

[0110] In some embodiments, the maximum change adjustment amount is the adjustment amplitude corresponding to the upper threshold or lower threshold of the preset error range from the set ideal polishing wheel speed, which is recorded as ΔV 1max ;

[0111] t2=ΔV 1max / dV1,t3=ΔL / V max , where dV1 is the fastest adjustment rate of the polishing wheel speed, V max is the maximum moving speed of the moving assembly 6, and ΔL represents the distance between two adjacent track points to be processed on the component to be polished 2.

[0112] In some embodiments, the method further comprises:

[0113] When the moving component 6 drives the polishing module to move from the first track point to the second track point, the second instantaneous current data collected by the control unit during the movement is filtered, and the filtered second instantaneous current data is compared with the ideal motor current under the current polishing gap;

[0114] If the number of second instantaneous current data collected by the control unit during the movement is recorded as a, then a satisfies the following formula:

[0115] .

[0116] In this embodiment, this method can avoid the influence of random signals and mutation signals generated during the second instantaneous current data on the measurement results of the second instantaneous current data, making the adjustment of the polishing gap more accurate.

[0117] In some embodiments, if the current polishing wheel speed V i The adjustment range to the upper limit threshold of the preset error range is recorded as +ΔV 1max , the corresponding current output value of the drive motor is A0+ΔA max , A0 represents the ideal motor current, ΔA max Indicates the corresponding current adjustment amplitude;

[0118] The polishing wheel speed V i The adjustment range to the lower limit threshold of the preset error range is recorded as -ΔV 1max , the corresponding current output value of the drive motor is A0-ΔA max ;

[0119] Control the current polishing wheel speed V of the drive motor 4 i Adjustments include:

[0120] If the current second instantaneous current data A i Does not exceed the permissible range of variation [A ′ ,A ′′ ], it is not necessary to control the driving motor 4 to the current polishing wheel speed V i Make adjustments;

[0121] If the current second instantaneous current data A i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |<|A0±ΔA max |, then control the drive motor 4 in combination with the corresponding relationship F va Current polishing wheel speed Adjust according to the following formula:

[0122]

[0123] If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |≥|A0±ΔA max |, then the current polishing wheel speed V i Adjust to V0±ΔV 1max, V0 represents the initially set polishing wheel speed; the second instantaneous current data A corresponding to the adjusted polishing wheel speed i Return to the permissible range of variation [A ′ ,A ′′ ]middle.

[0124] By adjusting the polishing wheel speed, the current A of the next processing point i+1 Within the allowable range of variation, the magnetorheological high-precision processing requirements are met.

[0125] Example 2: A magnetorheological processing method based on adjusting the liquid pump speed by motor current, according to the magnetorheological processing device based on adjusting the processing speed by motor current provided in the embodiment of the present invention, combined with Figures 1 to 3 , the method comprises the following steps:

[0126] The moving assembly 6 drives the polishing assembly to move to the location of the test optical element, and makes the polishing module 3 contact with the test optical element;

[0127] The control unit 5 calculates a correspondence between the liquid pump speed and the ideal motor current based on the first polishing data, the first polishing data including real-time current data of the drive motor 4 collected at the set liquid pump speed; and collects second instantaneous current data in real time, and compares the second instantaneous current data with the ideal motor current corresponding to the liquid pump speed in the correspondence. If the difference between the second instantaneous current data and the ideal motor current exceeds a preset error range, the polishing module 3 controls the second instantaneous current data collected after adjusting the liquid pump speed to ensure that the difference between the second instantaneous current data and the ideal motor current is within the preset error range.

[0128] The second instantaneous current data is the current data of the driving motor 4 collected in real time by the control unit 5 when the driving motor 4 drives the polishing module 3 at a constant speed to polish the component to be polished.

[0129] In this embodiment, it is necessary to first obtain the correspondence between the ideal motor current and the liquid pump speed. The moving component 6 drives the polishing module 3 to move to the position of the test optical element and contact the test optical element. In this process, the contact between the test optical element and the polishing module 3 means that the polishing wheel contacts the outer surface of the test optical element through the magnetorheological medium, and the part where the polishing module 3 contacts the test optical element is recorded as the first processing point. During the measurement of the same set of first polishing data, the first processing point remains unchanged. Optionally, when measuring multiple sets of first polishing data, different first processing points can be selected on the test optical element to facilitate improving the accuracy of the correspondence between the ideal motor current and the liquid pump speed.

[0130] During the process of polishing the test optical element by the polishing module 3, the control unit 5 controls the polishing module 3 to set different liquid pump speeds, collects the first instantaneous current data corresponding to different liquid pump speeds, maps and stores multiple sets of first instantaneous current data with the corresponding liquid pump speeds, and obtains the first polishing data. The control unit 5 calculates the corresponding relationship between the liquid pump speed and the ideal motor current based on the first polishing data.

[0131] After obtaining the correspondence between the ideal motor current and the liquid pump speed, the liquid pump speed of the polishing area of ​​the polishing element 2 to be polished can be adjusted according to the correspondence, so that the second instantaneous current data corresponding to the adjusted current liquid pump speed is placed in the same preset error range as the ideal motor current. This process does not require calibration steps for parameters such as gravity compensation, and will not be affected by the weight of the magnetorheological processing module of the robotic magnetorheological processing equipment, the equipment's own operating accuracy, operating speed, posture, inertia and other factors. The accuracy of the measurement data is only limited by the current measurement accuracy of the second instantaneous current data. The measurement results are more accurate, and there is no need to add high-precision force sensors and other equipment, thereby reducing equipment costs.

[0132] In some embodiments, the corresponding relationship between the liquid pump speed and the ideal motor current is a function curve relationship, and the function curve relationship is fitted according to the discrete values ​​of the liquid pump speed SV and the first instantaneous current data A to obtain the corresponding relationship F sa for:

[0133] .

[0134] In this embodiment, a plurality of liquid pump rotation speeds SV correspond to a plurality of first instantaneous current data A. Both the liquid pump rotation speed SV and the first instantaneous current data A are discrete values. Therefore, the discrete values ​​need to be fitted.

[0135] Fitting process: The discrete data was imported into Matlab software and fitted using the polyfit command in Matlab to determine the relationship between the liquid pump speed and the ideal motor current parameters. The Polyfit command is a basic, general command in Matlab. The resulting relationship between the liquid pump speed and the ideal motor current was determined. In this embodiment, the relationship between the liquid pump speed and the ideal motor current was a functional relationship.

[0136] In this way, the corresponding relationship between the ideal motor current and the liquid pump speed can be more intuitively seen. Based on this, multiple components 2 to be polished under the same polishing conditions can be polished.

[0137] In some embodiments, if the sampling period for collecting the second instantaneous current data is recorded as t1, the shortest time required for the liquid pump speed to complete the set maximum change adjustment amount is recorded as t2, and the shortest switching time between two adjacent trajectory points to be processed on the component to be polished 2 is recorded as t3;

[0138] Methods include:

[0139] Determine whether the relationship between t1, t2, and t3 satisfies the formula:

[0140] ;

[0141] If not, the sampling frequency of the control unit for collecting the second instantaneous current data is adjusted until the above formula is satisfied and the sampling frequency is 1 / t1.

[0142] In this embodiment, the above formula gives the correspondence between the three time elements, namely: within a single sampling cycle, the moving component 6 can adjust the polishing module 3 so that it moves to the liquid pump speed corresponding to the ideal motor current before performing the next sampling, thereby avoiding the sampling cycle being too long resulting in the sampling frequency being too slow, causing the sampling frequency to not match the adjustment speed of the liquid pump speed or the adjustment to be untimely, resulting in the inability to know the current state of the second instantaneous current data, affecting the automatic compensation function of the liquid pump speed.

[0143] In some embodiments, the maximum change adjustment amount is the adjustment amplitude corresponding to the adjustment from the set ideal liquid pump speed to the upper threshold or lower threshold of the preset error range, which is recorded as ΔSV max ;

[0144] t2=ΔSV max / SV max , t3=ΔL / V max , where SV max is the maximum speed adjustment rate of the liquid pump, V max is the maximum moving speed of the moving assembly 6, and ΔL represents the distance between two adjacent track points to be processed on the component to be polished 2.

[0145] In some embodiments, the method further comprises:

[0146] When the moving component 6 drives the polishing module to move from the first track point to the second track point, the second instantaneous current data collected by the control unit during the movement is filtered, and the filtered second instantaneous current data is compared with the ideal motor current under the current polishing gap;

[0147] If the number of second instantaneous current data collected by the control unit during the movement is recorded as a, then a satisfies the following formula:

[0148] .

[0149] In this embodiment, this method can avoid the influence of random signals and mutation signals generated during the second instantaneous current data on the measurement results of the second instantaneous current data, making the adjustment of the polishing gap more accurate.

[0150] In some embodiments, if the current liquid pump speed SV i The adjustment range to the upper threshold of the preset error range is recorded as +ΔSV max , the corresponding current output value of the drive motor 4 is A0+ΔA max , A0 represents the ideal motor current, ΔA max Indicates the corresponding current adjustment range; the current liquid pump speed SV i The adjustment range to the lower limit threshold of the preset error range is recorded as -ΔSV max , the corresponding current output value of the drive motor 4 is A0-ΔA max ;

[0151] Control polishing module 3 to the current liquid pump speed SV i Adjustments include:

[0152] If the current second instantaneous current data A i Does not exceed the permissible range of variation [A ′ ,A ′′ ], there is no need to adjust the current liquid pump speed SV i Make adjustments;

[0153] If the current second instantaneous current data A i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |<|A0±ΔA max |, then control the polishing module 3 in combination with the corresponding relationship F sa Current liquid pump speed SV i Adjust according to the following formula:

[0154] ;

[0155] If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |≥|A0±ΔA max |, then the current liquid pump speed SV i Adjusted to SV0±ΔSV maxSV0 represents the initially set liquid pump speed, so that the second instantaneous current data A corresponding to the adjusted liquid pump speed is i Return to the permissible range of variation [A ′ ,A ′′ ]middle.

[0156] Based on the liquid pump speed SV i The change of the current A at the next processing point is regulated. i+1 Within the allowable range of variation, the magnetorheological high-precision processing requirements are met.

[0157] In all the above embodiments, all preset and set values ​​and ranges are adaptively set and adjusted according to actual conditions, and the present invention does not limit this.

[0158] 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.

[0159] 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 machining device that adjusts machining speed based on motor current, characterized in that: The device comprises: A polishing assembly, comprising a drive motor and a polishing module, wherein the drive motor is used to drive the polishing module to move; A moving assembly, rigidly connected to the polishing assembly, for driving the polishing assembly to move to the location of the element to be polished; a control unit, controlling the polishing module to perform fixed-point processing on the polishing element at different processing speeds, collecting the instantaneous current of the drive motor in real time, and adjusting the processing speed according to the instantaneous current; The processing rotation speed includes the polishing wheel rotation speed of the polishing wheel in the polishing module and the liquid pump rotation speed of the liquid pump.

2. The magnetorheological processing device according to claim 1, wherein the magnetorheological processing device is characterized in that: In the control unit: Calculating the corresponding relationship between the machining speed and the set ideal motor current according to the first polishing data, wherein the first polishing data includes first instantaneous current data of the driving motor at the set machining speed; and for collecting second instantaneous current data in real time, and comparing the second instantaneous current data with the ideal motor current corresponding to the current machining speed in the corresponding relationship; if the difference between the two exceeds a preset error range, controlling the polishing assembly to adjust the current machining speed so that the difference between the second instantaneous current data collected after the machining speed adjustment and the ideal motor current is within the preset error range; The second instantaneous current data is the current data of the driving motor collected in real time by the control unit when the driving motor drives the polishing module at a constant speed to polish the component to be polished.

3. The magnetorheological machining device according to claim 1, wherein: The polishing module comprises: A magnetorheological mounting frame is connected to the moving assembly; the driving motor is arranged on the magnetorheological mounting frame, and the polishing wheel is arranged on the magnetorheological mounting frame; the driving motor drives the polishing wheel to rotate and adjusts the polishing wheel speed; a magnet, disposed on the magnetorheological mounting frame and close to a working point of the polishing wheel; A magnetorheological medium is connected to the polishing wheel, and is used to enter the magnetic field working area of ​​the magnet under the drive of the polishing wheel to form a magnetorheological ribbon, wherein the size parameters of the magnetorheological ribbon change with the polishing gap and the magnetic field strength, and is used to polish the component to be polished; The nozzle is arranged on the magnetorheological mounting frame through a nozzle mounting seat, the liquid pump conveys the magnetorheological medium to the nozzle, and the nozzle provides the magnetorheological medium to the polishing wheel.

4. A magnetorheological machining method for adjusting the polishing wheel speed based on motor current, according to any one of claims 1 to 3, wherein the magnetorheological machining device for adjusting the machining speed based on motor current is characterized in that: The method comprises the following steps: The moving assembly drives the polishing assembly to move to the location of the test optical element, and makes the polishing module contact with the test optical element; The control unit calculates a correspondence between a polishing wheel speed and an ideal motor current based on first polishing data, the first polishing data including real-time current data of the drive motor collected at different polishing wheel speed settings; and collects second instantaneous current data in real time, and compares the second instantaneous current data with the ideal motor current corresponding to the current polishing wheel speed in the correspondence. If a difference between the second instantaneous current data and the ideal motor current in the correspondence exceeds a preset error range, the control unit controls the drive motor to adjust the current polishing wheel speed so that the difference between the adjusted second instantaneous current data and the ideal motor current is within the preset error range. The second instantaneous current data is the current data of the driving motor collected in real time by the control unit when the driving motor drives the polishing module at a constant speed to polish the component to be polished.

5. The magnetorheological machining method according to claim 4, wherein: If the sampling period for collecting the second instantaneous current data is recorded as t1, the shortest time required for the polishing wheel speed to complete the set maximum change adjustment amount is recorded as t2, and the shortest switching time between two adjacent track points to be processed on the component to be polished is recorded as t3; The method comprises: Determine whether the relationship between t1, t2, and t3 satisfies the formula: ； If it is not satisfied, the sampling frequency of the control unit for collecting the second instantaneous current data is adjusted until the above formula is satisfied, and the sampling frequency is 1 / t1.

6. The magnetorheological machining method according to claim 5, wherein: The maximum change adjustment amount is the adjustment range corresponding to the upper threshold or lower threshold of the preset error range from the set ideal polishing wheel speed, which is recorded as ΔV 1max ; t2=ΔV 1max / dV1,t3=ΔL / V max , where dV1 is the fastest adjustment rate of the polishing wheel speed, V max is the maximum moving speed of the moving assembly, and ΔL represents the distance between two adjacent track points to be processed on the component to be polished.

7. The magnetorheological machining method according to claim 5, wherein: The method further comprises: When the moving assembly drives the polishing module to move from the first track point to the second track point, filtering the second instantaneous current data collected by the control unit during the movement, and comparing the filtered second instantaneous current data with the ideal motor current under the current polishing gap; If the number of second instantaneous current data collected by the control unit during the movement is recorded as a, then a satisfies the following formula: 。 8. The magnetorheological machining method according to claim 4, wherein: If the current polishing wheel speed V i The adjustment range to the upper limit threshold of the preset error range is recorded as +ΔV 1max , the corresponding current output value of the drive motor is A0+ΔA max , A0 represents the ideal motor current, ΔA max Indicates the corresponding current adjustment amplitude; By polishing wheel speed The adjustment range to the lower limit threshold of the preset error range is recorded as -ΔV 1max , the corresponding current output value of the drive motor is A0-ΔA max ; Control the driving motor to the current polishing wheel speed V i Adjustments include: If the current second instantaneous current data A i Does not exceed the permissible range of variation [A ′ ,A ′′ ], it is not necessary to control the driving motor to the current polishing wheel speed V i Make adjustments; If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |<|A0±ΔA max |, then control the drive motor according to the corresponding relationship F va The current polishing wheel speed V i Adjust according to the following formula: ； If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |≥|A0±ΔA max |, then the current polishing wheel speed V i Adjust to V0±ΔV 1max , V0 represents the initially set polishing wheel speed; the second instantaneous current data A corresponding to the adjusted polishing wheel speed i Return to the permissible range of variation [A ′ ,A ′′ ]middle.

9. A magnetorheological machining method for adjusting the speed of a liquid pump based on motor current, according to any one of claims 1 to 3, wherein: The method comprises the following steps: The moving assembly drives the polishing assembly to move to the location of the test optical element, and makes the polishing module contact with the test optical element; The control unit calculates a correspondence between a liquid pump speed and an ideal motor current based on first polishing data, the first polishing data including real-time current data of the drive motor collected at different liquid pump speed settings; and collects second instantaneous current data in real time, and compares the second instantaneous current data with the ideal motor current corresponding to the current liquid pump speed in the correspondence. If a difference between the second instantaneous current data and the ideal motor current in the correspondence exceeds a preset error range, the control unit controls the polishing module to adjust the current liquid pump speed so that the difference between the adjusted second instantaneous current data and the ideal motor current is within the preset error range. The second instantaneous current data is the current data of the driving motor collected in real time by the control unit when the driving motor drives the polishing module at a constant speed to polish the component to be polished.

10. The magnetorheological machining method based on regulating the liquid pump speed by motor current according to claim 9, characterized in that: If the sampling period for collecting the second instantaneous current data is recorded as t1, the shortest time required for the liquid pump speed to complete the set maximum change adjustment amount is recorded as t2, and the shortest switching time between two adjacent track points to be processed on the component to be polished is recorded as t3; The method comprises: Determine whether the relationship between t1, t2, and t3 satisfies the following formula: ； If not, the sampling frequency of the control unit for collecting the second instantaneous current data is adjusted until the above formula is satisfied, and the sampling frequency is set to 1 / t1.

11. The magnetorheological machining method according to claim 10, wherein: The maximum change adjustment amount is the adjustment range corresponding to the upper threshold or lower threshold of the preset error range adjusted from the set ideal liquid pump speed, which is recorded as ΔSV max ; t2=ΔSV max / SV max , t3=ΔL / V max , where SV max is the maximum speed adjustment rate of the liquid pump, V max is the maximum moving speed of the moving assembly, and ΔL represents the distance between two adjacent track points to be processed on the element to be polished.

12. The magnetorheological machining method based on regulating the liquid pump speed by motor current according to claim 10, characterized in that: The method further comprises: When the moving assembly drives the polishing module to move from the first track point to the second track point, filtering the second instantaneous current data collected by the control unit during the movement, and comparing the filtered second instantaneous current data with the ideal motor current under the current polishing gap; If the number of second instantaneous current data collected by the control unit during the movement is recorded as a, then a satisfies the following formula: 。 13. The magnetorheological machining method according to claim 9, wherein: If the current liquid pump speed SV i The adjustment range to the upper limit threshold of the preset error range is recorded as +ΔSV max , the corresponding current output value of the drive motor is A0+ΔA max , A0 represents the ideal motor current, ΔA max Indicates the corresponding current adjustment amplitude; The current liquid pump speed SV i The adjustment range to the lower limit threshold of the preset error range is recorded as -ΔSV max , the corresponding current output value of the drive motor is A0-ΔA max ; Control the polishing module to adjust the current liquid pump speed SV i Adjustments include: If the current second instantaneous current data A i Does not exceed the permissible range of variation [A ′ ,A ′′ ], there is no need to control the polishing module to the current liquid pump speed SV i Make adjustments; If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |<|A0±ΔA max |, then control the polishing module to combine the corresponding relationship F sa Current liquid pump speed SV i Adjust according to the following formula: ； If the second instantaneous current data A of the current driving motor i Beyond the permissible range of variation [A ′ ,A ′′ ] and|A i |≥|A0±ΔA max |, then the current liquid pump speed SV i Adjusted to SV0±ΔSV max SV0 represents the initially set liquid pump speed; the second instantaneous current data A corresponding to the adjusted liquid pump speed i Return to the permissible range of variation [A ′ ,A ′′ ]middle.

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