Magnetorheological polishing equipment and method based on machine vision to adjust processing speed

Abstract

The present invention relates to the field of optical processing technology, and in particular to a magnetorheological polishing device and method for adjusting a processing speed based on machine vision. The device comprises a robot, a control unit, a magnetorheological processing module, and a machine vision device. The magnetorheological processing module is arranged at the free end of the robot. The robot drives a polishing wheel in the magnetorheological processing module to process an optical element using a magnetorheological fluid as a medium, and the machine vision device measures the ribbon thickness of the magnetorheological fluid during the processing. In the method, the real-time change of the ribbon thickness of the magnetorheological fluid during the magnetorheological processing is measured by the machine vision device, and the parameters related to the processing speed are then adjusted in real time, thereby achieving real-time constant control of the removal function.

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 for adjusting processing speed based on machine vision. Background Art

[0002] Magnetorheological finishing (MRF) is an advanced optical manufacturing technology that has been developed in recent years. It offers numerous advantages, including stable removal performance, controllable edge effects, minimal subsurface damage, no photocopying, strong shape-modifying capabilities, and high machining accuracy. Consequently, MRF has garnered widespread attention in high-precision optical processing. The hardware of existing magnetorheological polishing equipment mainly includes three parts: motion actuator, circulation system and polishing wheel module. The motion actuator is usually a CNC machine tool, but CNC machine tools have some shortcomings (such as low degree of freedom, large footprint, high cost, etc.), which limit the deviation of aspheric surfaces and make it difficult to perform precise posture control along the surface normal. The most important component in the circulation system is the supply source. Peristaltic pumps and centrifugal pumps are currently the main types of magnetorheological fluid supply sources. Peristaltic pumps will produce a pulse effect when working, which in turn affects the stability of the magnetorheological fluid in pipeline transportation, and ultimately affects the stability of the removal function. The centrifugal pump has a small pulse effect when working, and the magnetorheological fluid is more stable when transported in the pipeline, and has less impact on the change of the removal function. Therefore, it is more suitable for magnetorheological supply systems. However, there is still a major problem with using a centrifugal pump as the supply source for the magnetorheological fluid supply system: when the water outlet (nozzle) of the supply system is processed along the curved surface of the optical component, the nozzle will move up and down within the working area. When the position of the centrifugal pump is constant, the pressure between the centrifugal pump and the nozzle will change, and the originally stable magnetorheological fluid will also change. The thickness and width of the ribbon formed by the magnetorheological fluid after passing through the polishing gap will also change accordingly, resulting in a change in the removal function and affecting the final processing accuracy.

[0003] In 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, it is theoretically possible to achieve high-precision processing of large-aperture complex curved optical components.

[0004] However, due to the influence of factors such as processing, assembly, load, trajectory planning and reduction ratio, the execution accuracy of the robot's free end 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. The requirements for the change of the polishing gap during the polishing process are high. 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. This leads to large changes in the polishing gap during the processing. The thickness of the ribbon will change after the magnetorheological fluid passes through the polishing gap, and the certainty of the removal function is reduced, affecting the final processing accuracy. Therefore, the motion accuracy of the current commercial large-scale six-degree-of-freedom industrial robots often cannot meet the requirements of magnetorheological polishing technology for the change of the removal function during high-precision polishing.

[0005] For the flow rate change problem in the centrifugal pump supply system, the commonly used method is to add a follower device to keep the vertical distance between the centrifugal pump and the nozzle outlet unchanged. However, these methods require the additional follower device to have high motion performance to keep the vertical distance from the nozzle unchanged at all times. Some solutions even place the follower device on the Z-axis of the CNC machine tool, which undoubtedly increases the motion load and equipment cost of the motion mechanism and reduces the motion performance of the equipment. In addition, the follower device cannot strictly guarantee the constant vertical distance between the centrifugal pump and the nozzle, resulting in changes in the removal function and affecting the final processing accuracy. Summary of the Invention

[0006] In view of this, the present invention aims to provide a magnetorheological polishing device and method for adjusting the processing speed based on machine vision. The real-time changes in the ribbon thickness of the magnetorheological fluid during magnetorheological processing are measured by machine vision equipment, and the parameters related to the processing speed are adjusted in real time, thereby realizing real-time constant control of the removal function.

[0007] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0008] A magnetorheological polishing device for adjusting processing speed based on machine vision comprises a robot, a control unit, a magnetorheological processing module, and a machine vision device. The magnetorheological processing module is disposed at the free end of the robot. The robot drives a polishing wheel in the magnetorheological processing module to process an optical element using magnetorheological fluid as a medium, and during the processing, the machine vision device measures the thickness of a ribbon of the magnetorheological fluid. The control unit comprises a time calculation module for calculating the measurement time of the machine vision device and the adjustment time of the magnetorheological processing module, and adjusting the machine vision device and the magnetorheological processing module based on the measurement time and adjustment time; a conversion relationship module for obtaining a first conversion relationship based on the ribbon thickness and the polishing wheel speed of the polishing wheel, and a second conversion relationship based on the ribbon thickness and the liquid pump speed of the liquid pump in the magnetorheological processing device; and a real-time control module for adjusting the polishing wheel speed or the liquid pump speed based on the conversion relationship, thereby maintaining the stability of the removal function when processing the optical element.

[0009] Furthermore, the magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a magnet and a magnetorheological mounting frame; wherein, the magnetorheological mounting frame is arranged on the free end, and the polishing wheel is arranged on the magnetorheological mounting frame; the polishing motor is connected to the polishing wheel through a transmission belt, so that the polishing motor controls the rotation of the polishing wheel and changes the speed of the polishing wheel; the nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the liquid pump transports magnetorheological fluid to the nozzle; the magnet is arranged on the magnetorheological mounting frame, and the magnet is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the magnet and changes the stiffness of the magnetorheological fluid.

[0010] Furthermore, the robot, machine vision device, polishing motor and liquid pump 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.

[0011] A magnetorheological polishing method based on the polishing wheel speed, according to the present invention, provides a magnetorheological polishing device for adjusting the processing speed based on machine vision, comprising the following steps:

[0012] A1: Controlling the magnetorheological processing module to process the test optical element, and obtaining a first conversion relationship through the conversion relationship module during the processing;

[0013] A2: Setting a first variable range of the polishing wheel speed and obtaining a second variable range corresponding to the ribbon thickness according to the first conversion relationship; setting a maximum polishing wheel speed and obtaining the corresponding maximum ribbon thickness according to the first conversion relationship;

[0014] A3: The control time calculation module is combined with the maximum polishing wheel speed to adjust the machine vision equipment and magnetorheological processing module;

[0015] A4: The optical component to be processed is processed in combination with the second variable range, the maximum polishing wheel speed and the maximum ribbon thickness. During the processing, the real-time control module adjusts the polishing wheel speed in real time.

[0016] Furthermore, step A1 includes the following steps:

[0017] A11: Control the polishing wheel to process the test optical element at different polishing gaps, calculate the volume removal rate of the removal function at each processing position, and use machine vision equipment to measure the ribbon thickness at each processing position in real time. In the conversion relationship module, a third conversion relationship between the ribbon thickness and the volume removal rate of the removal function is obtained;

[0018] A12: Changing the polishing wheel speed individually to control the polishing wheel to process the test optical element at different polishing gaps, obtaining the removal function volume removal rate at each processing position, and obtaining a fourth conversion relationship between the removal function volume removal rate and the polishing wheel speed in the conversion relationship module;

[0019] A13: Obtain a first conversion relationship according to the third conversion relationship and the fourth conversion relationship.

[0020] Furthermore, in step A4, when the polishing wheel is controlled to move to the current processing position, the current ribbon thickness measured by the machine vision device is compared with the second variable range:

[0021] If the current ribbon thickness is within the second variable range, there is no need to adjust the current polishing wheel speed;

[0022] If the current ribbon thickness is not within the second variable range, the current polishing wheel speed needs to be adjusted:

[0023] If the current ribbon thickness is greater than or equal to the maximum ribbon thickness, adjust the current polishing wheel speed to the maximum polishing wheel speed;

[0024] If the current ribbon thickness is less than the maximum ribbon thickness, the current polishing wheel speed is adjusted according to the following formula:

[0025] ;

[0026] in, Represents the first conversion relationship, Indicates the current ribbon thickness, Indicates the polishing wheel speed.

[0027] A magnetorheological polishing method based on the speed of a liquid pump, according to the present invention, includes the following steps:

[0028] B1: Controlling the magnetorheological processing module to process the test optical element, and obtaining the second conversion relationship through the conversion relationship module during the processing;

[0029] B2: Setting the third variable range of the liquid pump speed and obtaining the fourth variable range corresponding to the ribbon thickness according to the second conversion relationship; setting the maximum liquid pump speed and obtaining the corresponding maximum ribbon thickness according to the second conversion relationship;

[0030] B3: The control time calculation module is combined with the maximum liquid pump speed to adjust the machine vision equipment and magnetorheological processing module;

[0031] B4: The optical element to be processed is processed in combination with the fourth variable range, the maximum liquid pump speed, and the maximum ribbon thickness. During the processing, the real-time control module adjusts the position of the electromagnet in real time.

[0032] Furthermore, step B1 includes the following steps:

[0033] B11: Control the polishing wheel to process the test optical element at different polishing gaps, calculate the volume removal rate of the removal function at each processing position, and simultaneously measure the ribbon thickness at each processing position in real time using a machine vision device. The fifth conversion relationship between the volume removal rate of the removal function and the ribbon thickness is obtained in the conversion relationship module.

[0034] B12: Changing the liquid pump speed of the liquid pump individually and controlling the polishing wheel to process the test optical element at different polishing gaps to obtain the removal function volume removal rate at each processing position, and obtaining a sixth conversion relationship between the removal function volume removal rate and the liquid pump speed in the conversion relationship module;

[0035] B13: Obtain a second conversion relationship according to the fifth conversion relationship and the sixth conversion relationship.

[0036] Furthermore, in step B4, when the polishing wheel is controlled to move to the current processing position, the current ribbon thickness measured by the machine vision device is compared with the fourth variable range:

[0037] If the current ribbon thickness is within the fourth variable range, there is no need to adjust the current liquid pump speed;

[0038] If the current ribbon thickness is not within the fourth variable range, the current liquid pump speed needs to be adjusted:

[0039] If the current ribbon thickness is greater than or equal to the maximum ribbon thickness, the current liquid pump speed is adjusted to the maximum liquid pump speed;

[0040] If the current ribbon thickness is less than the maximum ribbon thickness, the current liquid pump speed is adjusted according to the following formula:

[0041]

[0042] in, Represents the second conversion relationship, Indicates the thickness of the ribbon, Indicates the current liquid pump speed.

[0043] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0044] In the magnetorheological polishing equipment and method for adjusting the processing speed based on machine vision created by the present invention, the thickness of the magnetorheological fluid ribbon in the six-dimensional processing of the magnetorheological processing module driven by the robot is measured in real time by machine vision equipment, thereby adjusting the processing speed in the magnetorheological processing module in real time, thereby achieving 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

[0045] 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:

[0046] Figure 1 A schematic structural diagram of a magnetorheological polishing device for adjusting the processing speed based on machine vision according to an embodiment of the present invention from one perspective;

[0047] Figure 2 A schematic structural diagram of a magnetorheological polishing device for adjusting the processing speed based on machine vision according to an embodiment of the present invention from another perspective;

[0048] Figure 3 This is a schematic structural diagram of a liquid pump according to an embodiment of the present invention.

[0049] Description of reference numerals:

[0050] 1. Robot; 2. Control unit; 3. Machine vision equipment; 4. Laboratory bench; 5. Optical element to be processed; 6. Test optical element; 7. Polishing wheel; 8. Liquid pump; 9. Transmission belt; 10. Polishing motor; 11. Nozzle; 12. Magnet; 13. Magnetorheological 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; 21. Mounting bracket; 22. Connecting plate. DETAILED DESCRIPTION

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0056] like Figure 1 and Figure 2 As shown, the magnetorheological polishing device for adjusting the machining speed based on machine vision, as described in an embodiment of the present invention, includes a robot 1, a control unit 2, a magnetorheological machining module, and a machine vision device 3. The magnetorheological machining module is mounted on the free end of the robot 1. The robot 1 drives the polishing wheel 7 in the magnetorheological machining module to process an optical element 5 or a test optical element 6 placed on a laboratory table 4 using magnetorheological fluid as a medium. The machine vision device 3 is mounted on one side of the laboratory table 4 and measures the thickness of the magnetorheological fluid ribbon during the machining process. During the processing, the ribbon thickness of the magnetorheological fluid is affected by the supply system for providing the magnetorheological fluid and the polishing gap, and the polishing gap is changed by the polishing wheel position, robot posture adjustment, etc. Therefore, it is necessary to use a machine vision device 3 mounted on one side of the experimental table 4 to measure the change in the ribbon thickness of the magnetorheological fluid in real time. In an embodiment of the present invention, the machine vision device 3 uses a binocular stereo camera of the Stereo ace model of Basler. The process of using the machine vision device 3 to measure the ribbon thickness of the magnetorheological fluid includes: the machine vision device 3 collects the contour information of the polishing wheel 7 and the ribbon, and takes any point in the non-working area of ​​the surface of the polishing wheel 7 as the reference point. The highest point on the surface of the magnetorheological fluid ribbon is the measurement point, and the height difference between the measurement point and the reference point is the change data of the ribbon thickness.

[0057] The control unit 2 includes a time calculation module, a conversion relationship module, and a real-time control module. The time calculation module is used to calculate the measurement time of the machine vision device 3 and the adjustment time of the magnetorheological processing module, and to adjust the machine vision device 3 and the magnetorheological processing module based on the measurement time and adjustment time. The conversion relationship module is used to obtain a first conversion relationship based on the ribbon thickness and the polishing wheel speed of the polishing wheel 7, and a second conversion relationship based on the ribbon thickness and the liquid pump speed of the liquid pump 8 in the magnetorheological processing device. The real-time control module is used to adjust the polishing wheel speed or the liquid pump speed based on the conversion relationship, thereby maintaining the stability of the removal function when processing the optical element 5 to be processed or the test optical element 6.

[0058] The magnetorheological processing module also includes a transmission belt 9, a polishing motor 10, a nozzle 11, a magnet 12 and a magnetorheological mounting frame 13. Among them, the magnetorheological mounting frame 13 is fixed to the free end of the robot 1, and the polishing wheel 7 is mounted on the magnetorheological mounting frame 13. The polishing motor 10 is mounted on the magnetorheological mounting frame 13, and the output end of the polishing motor 10 is connected to the polishing wheel 7 through the transmission belt 9, so that the polishing motor 10 controls the polishing wheel 7 to rotate and changes the polishing wheel speed. The way in which the polishing motor 10 drives the polishing wheel 7 to rotate in the embodiment of the present invention can refer 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 mounted on the magnetorheological mounting frame 13 along the rotation direction of the polishing wheel 7. The liquid pump 8 is mounted on one side of the experimental table 4 through the mounting frame 21, and the liquid pump 8 delivers magnetorheological fluid to the nozzle 11. The nozzle 11 sprays magnetorheological fluid toward the working point of the polishing wheel 7, thereby causing the polishing wheel 7 to process the optical element 5 to be processed or the test optical element 6 using the magnetorheological fluid as a medium. The magnet 12 is mounted on the magnetorheological mounting frame 13 via the connecting plate 22, and the magnet 12 is close to the working point of the polishing wheel 7, so that the magnetorheological fluid is affected by the magnetic field strength of the magnet 12, thereby changing the stiffness of the magnetorheological fluid. 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 optical element 5 to be processed or the test optical element 6, along the normal direction of the surface of the optical element 5 to be processed or the test optical element 6.

[0059] 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 primarily stores cooling water and cools the magnetorheological fluid. The magnetorheological fluid storage chamber 16 primarily stores 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 8 is adjusted by a motor, which allows the pump 8 to change its speed.

[0060] The robot 1, machine vision device 3, polishing motor 10, and motor of liquid pump 8 are each connected to control unit 2 to form respective communication lines, enabling control unit 2 to receive and send signals via the corresponding communication lines. Control unit 2 communicates with the motors via the communication lines. During operation, control unit 2 sends speed control commands in real time, which in turn adjusts the speed of liquid pump 8 in real time, thereby regulating the liquid flow rate. Because a strong magnetic field is generated around polishing wheel 7 during polishing, the communication lines are designed to avoid such strong magnetic fields.

[0061] Based on the magnetorheological polishing equipment for adjusting the processing speed based on machine vision described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological polishing method for adjusting the processing speed based on machine vision, including a magnetorheological polishing method based on the polishing wheel speed and a magnetorheological polishing method based on the liquid pump speed.

[0062] Specific embodiment 1: The magnetorheological polishing method based on the polishing wheel speed provided in this specific embodiment, the magnetorheological polishing device based on machine vision to adjust the processing speed according to the embodiment of the invention, combined with Figure 1 and Figure 2 , including the following steps:

[0063] A1: Control the magnetorheological processing module to process the test optical element 6, and obtain a first conversion relationship through the conversion relationship module during the processing. Step A1 includes the following steps:

[0064] A11: Control the polishing wheel 7 to process the test optical element 6 with different polishing gaps, calculate the removal function volume removal rate at each processing position, and measure the ribbon thickness at each processing position in real time through the machine vision device 3. In the conversion relationship module, obtain:

[0065] ;

[0066] in, represents the third conversion relationship between the ribbon thickness T and the removal function volume removal rate MRR; in this specific embodiment, specifically controlling the magnetorheological processing module to perform fixed-point processing on the test optical element 6 for a period of time;

[0067] A12: Change the polishing wheel speed individually and control the polishing wheel 7 to process the test optical element 6 at different polishing gaps to obtain the removal function volume removal rate at each processing position. In the conversion relationship module, obtain:

[0068] ;

[0069] in, Represents the removal function volume removal rate MRR and polishing wheel speed In this specific embodiment, specifically, the polishing wheel speed is changed separately, and the polishing wheel 7 is controlled to perform fixed-point processing on the test optical element 6 for a period of time at different polishing gaps;

[0070] A13: The first conversion relationship is obtained based on the third conversion relationship and the fourth conversion relationship, namely:

[0071]

[0072] in, Indicates the first conversion relationship.

[0073] A2: Set the polishing wheel speed The first variable range , and according to the first conversion relationship Get the second variable range corresponding to the ribbon thickness T ,Right now:

[0074] ;

[0075] ;

[0076] Set the maximum polishing wheel speed , and according to the first conversion relationship Get the corresponding maximum ribbon thickness ,Right now:

[0077] .

[0078] The first variable range and maximum polishing wheel speed The configuration is adaptive according to the actual situation and is not limited in this embodiment.

[0079] A3: The control time calculation module is combined with the maximum polishing wheel speed to adjust the machine vision device 3 and the magnetorheological processing module.

[0080] Step A3 includes the following steps:

[0081] A31. Count b data points measured by the machine vision device 3 within a second and obtain the time it takes for the machine vision device 3 to measure a point. ;

[0082] ;

[0083] A32. Calculate the change in maximum polishing wheel speed The time required to control the magnetorheological processing module :

[0084] ;

[0085] in, Indicates the rate of change of the rotation speed adjustment of the polishing wheel 7;

[0086] A33, measure the vertical distance between the measuring position of the machine vision device 3 and the working point of the polishing wheel 7 , according to the vertical distance and the set polishing wheel speed Calculate the time required for the polishing wheel 7 to reach the working point :

[0087] ;

[0088] in, Indicates the radius of the polishing wheel 7; polishing wheel speed The configuration is adaptive according to the actual situation, and this embodiment does not limit this.

[0089] A34, calculate the maximum speed of the magnetorheological processing module Minimum moving time between two adjacent processing positions :

[0090] ;

[0091] in, Indicates the distance between two adjacent processing positions;

[0092] A35. Calculation conditions Is it true: If the condition is true, then there is no need to adjust the machine vision device 3 and the polishing wheel 7; if the condition is not true, then the data sampling frequency of the machine vision device 3 and the polishing wheel speed need to be adjusted. Make adjustments to make the conditions true;

[0093] A36, the measurement data between each two adjacent processing positions are processed by mean filtering and then output, and the number of mean filtered data is Needs to be satisfied .

[0094] A4: Combined with the second variable range , Maximum polishing wheel speed and maximum ribbon thickness , the optical element 5 to be processed is processed, and during the processing, the real-time control module adjusts the polishing wheel speed V in real time. Specifically, it includes: controlling the polishing wheel 7 to move to the current processing position i, and measuring the current ribbon thickness of the machine vision device 3 With the second variable range Compare:

[0095] If the current ribbon thickness In the second variable range Within, that is , then there is no need to adjust the current polishing wheel speed Make adjustments;

[0096] If the current ribbon thickness Not in the second variable range Within, that is , you need to adjust the current polishing wheel speed Make adjustments:

[0097] If the current ribbon thickness Greater than or equal to the maximum ribbon thickness ,Right now , the current polishing wheel speed Adjust to maximum polishing wheel speed ;

[0098] If the current ribbon thickness Less than the maximum ribbon thickness ,Right now , according to the following formula to calculate the current polishing wheel speed Make adjustments:

[0099] .

[0100] Specific embodiment 2: The magnetorheological polishing method based on the liquid pump speed provided in this specific embodiment, the magnetorheological polishing device based on machine vision to adjust the processing speed according to the embodiment of the invention, combined with Figures 1 to 3 , including the following steps:

[0101] B1: Control the magnetorheological processing module to process the test optical element 6, and obtain the second conversion relationship through the conversion relationship module during the processing. Step B1 includes the following steps:

[0102] B11: Control the polishing wheel 7 to process the test optical element 6 with different polishing gaps, calculate the removal function volume removal rate at each processing position, and at the same time, the machine vision device 3 measures the ribbon thickness at each processing position in real time. In the conversion relationship module, the following is obtained:

[0103] ;

[0104] in, represents the fifth conversion relationship between the ribbon thickness T and the removal function volume removal rate MRR; in this specific embodiment, specifically, the polishing wheel 7 is controlled to perform fixed-point processing on the test optical element 6 for a period of time with different polishing gaps;

[0105] B12: Changing the liquid pump speed of the liquid pump 8 individually and controlling the polishing wheel 7 to process the test optical element 6 at different polishing gaps, the removal function volume removal rate at each processing position is obtained, and the conversion relationship module is used to obtain:

[0106] ;

[0107] in, Represents the removal function volume removal rate MRR and liquid pump speed In this specific embodiment, specifically, the liquid pump speed of the liquid pump 8 is changed separately, and the polishing wheel 7 is controlled to perform fixed-point processing on the test optical element 6 for a period of time at different polishing gaps;

[0108] B13: Obtain the second conversion relationship based on the fifth conversion relationship and the sixth conversion relationship, namely:

[0109]

[0110] in, Indicates the second conversion relationship.

[0111] B2: Set the third variable range of liquid pump speed , and according to the second conversion relationship Get the fourth variable range corresponding to the ribbon thickness ,Right now:

[0112] ;

[0113] ;

[0114] Set the maximum liquid pump speed , and according to the second conversion relationship Get the corresponding maximum ribbon thickness ,Right now:

[0115] .

[0116] The third variable range and maximum liquid pump speed The configuration is adaptive according to the actual situation and is not limited in this embodiment.

[0117] B3: The control time calculation module is combined with the maximum liquid pump speed to adjust the machine vision device and the magnetorheological processing module. Step B3 includes the following steps:

[0118] B31. Count b data points measured by machine vision device 3 within a second and obtain the time it takes for machine vision device 3 to measure a point. ;

[0119] ;

[0120] B32. Calculate the maximum liquid pump speed adjustment The time required to control the magnetorheological processing module :

[0121] ;

[0122] in, Indicates the rate of change of the speed adjustment of the liquid pump 8;

[0123] B33, measure the vertical distance between the measuring position of the machine vision device 3 and the working point of the polishing wheel 7 , according to the vertical distance and the set polishing wheel speed Calculate the time required for the polishing wheel 7 to reach the working point :

[0124] ;

[0125] in, Indicates the radius of the polishing wheel 7; polishing wheel speed The configuration is adaptive according to the actual situation, and this embodiment does not limit this.

[0126] B34. Calculate the maximum speed of the magnetorheological machining module Minimum moving time between two adjacent processing positions :

[0127] ;

[0128] in, Indicates the distance between two adjacent processing positions;

[0129] B35. Calculation conditions Is it true: If the condition is true, then there is no need to adjust the machine vision device 3 and the polishing wheel 7; if the condition is not true, then the data sampling frequency of the machine vision device 3 and the polishing wheel speed need to be adjusted. Make adjustments to make the conditions true;

[0130] B36, perform mean filtering on the measurement data between each two adjacent processing positions before outputting them, and the number of mean filtered data Needs to be satisfied .

[0131] Since the magnetorheological fluid ejected from the liquid pump 8 needs to be transported through the pipeline and driven by the polishing wheel 7 to reach the working area, in order to ensure that the adjustment of the removal function change is achieved at the target trajectory point, it is necessary to set the residence time of each processing point. The specific setting method is as follows:

[0132] The Z-axis coordinate of the nozzle opening position of the nozzle 11 is measured by the machine vision device 3 The Z-axis coordinate of the lowest point of the polishing wheel 7 , then the vertical distance between the nozzle opening of the nozzle 11 and the lowest point of the polishing wheel 7 is |Z4-Z5|, and the time required for the magnetorheological fluid ejected from the nozzle to reach the lowest point of the polishing wheel is :

[0133] ;

[0134] Where n represents the number of revolutions per second of the polishing wheel 7, L represents the length of the pipeline, and V represents the flow rate of the magnetorheological fluid. When generating the processing control program, if the dwell time of each point is If the dwell time of some processing points exists, the generated processing control program is appropriate. , it is necessary to increase the material removal thickness, extend the processing time, and regenerate the processing control program so that the processing residence time of each point is .

[0135] B4: Combined with the fourth variable range , Maximum liquid pump speed and maximum ribbon thickness , the optical element 5 to be processed is processed, and during the processing, the real-time control module adjusts the speed of the liquid pump in real time. In step B4, when the polishing wheel 7 is controlled to move to the current processing position i, the current ribbon thickness measured by the machine vision device 3 is With the fourth variable range Compare:

[0136] If the current ribbon thickness In the fourth variable range Within, that is , then there is no need to adjust the current liquid pump speed Make adjustments;

[0137] If the current ribbon thickness Not in the fourth variable range Within, that is , then the current liquid pump speed needs to be Make adjustments:

[0138] If the current ribbon thickness Greater than or equal to the maximum ribbon thickness ,Right now , the current liquid pump speed Adjust to maximum liquid pump speed ;

[0139] If the current ribbon thickness Less than the maximum ribbon thickness ,Right now , calculate the current liquid pump speed according to the following formula Make adjustments:

[0140] .

[0141] All the conversion relationships in the above specific embodiments are obtained through fitting. The fitting process includes but is not limited to importing discrete data into Matlab software, using Matlab's polyfit fitting command to complete data fitting, and solving the respective conversion relationships. Polyfit fitting command is a basic general command of Matlab software. This method can more intuitively see the corresponding relationship between the correlations and the corresponding function curves.

[0142] 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.

[0143] 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 that adjusts the processing speed based on machine vision, characterized by: The device comprises a robot, a control unit, a magnetorheological processing module, and a machine vision device; wherein: the magnetorheological processing module is arranged at the free end of the robot; the robot drives the polishing wheel in the magnetorheological processing module to process the optical element using magnetorheological fluid as the medium, and the machine vision device measures the thickness of the magnetorheological fluid ribbon during the processing; The interior of the control unit includes: a time calculation module for calculating a measurement time of the machine vision device and an adjustment time of the magnetorheological processing module, and adjusting the machine vision device and the magnetorheological processing module according to the measurement time and the adjustment time; a conversion relationship module, which obtains a first conversion relationship based on the thickness of the ribbon and the polishing wheel speed of the polishing wheel, and obtains a second conversion relationship based on the thickness of the ribbon and the liquid pump speed of the liquid pump in the magnetorheological processing equipment; The real-time control module adjusts the polishing wheel rotation speed according to the first conversion relationship, or adjusts the liquid pump rotation speed according to the second conversion relationship, so as to keep the removal function stable when processing the optical element.

2. The magnetorheological polishing equipment for adjusting the processing speed based on machine vision according to claim 1 is characterized in that: The magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a magnet and a magnetorheological mounting frame; wherein, The magnetorheological mounting frame is arranged on the free end, and the polishing wheel is arranged on the magnetorheological mounting frame; The polishing motor is connected to the polishing wheel through the transmission belt, so that the polishing motor controls the rotation of the polishing wheel and changes the speed of the polishing wheel; The nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the liquid pump delivers magnetorheological fluid to the nozzle; The magnet is arranged on the magnetorheological mounting frame and is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the magnet and the rigidity of the magnetorheological fluid is changed.

3. The magnetorheological polishing equipment for adjusting the processing speed based on machine vision according to claim 2 is characterized in that: The robot, the machine vision device, the polishing motor and the liquid pump 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.

4. A magnetorheological polishing method based on polishing wheel speed, based on the magnetorheological polishing device with machine vision-based processing speed adjustment according to any one of claims 1 to 3, characterized in that: The following steps are involved: A1: controlling the magnetorheological processing module to process the test optical element, and obtaining the first conversion relationship through the conversion relationship module during the processing; A2: setting a first variable range of the polishing wheel speed, and obtaining a second variable range corresponding to the ribbon thickness according to the first conversion relationship; setting a maximum polishing wheel speed, and obtaining a corresponding maximum ribbon thickness according to the first conversion relationship; A3: Controlling the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum polishing wheel speed; A4: The optical element to be processed is processed in combination with the second variable range, the maximum polishing wheel speed and the maximum ribbon thickness. During the processing, the real-time control module adjusts the polishing wheel speed in real time.

5. The magnetorheological polishing method based on polishing wheel speed according to claim 4, characterized in that: Step A1 includes the following steps: A11: controlling the polishing wheel to process the test optical element at different polishing gaps, calculating the removal function volume removal rate at each processing position, and measuring the ribbon thickness at each processing position in real time using the machine vision device, and obtaining a third conversion relationship between the ribbon thickness and the removal function volume removal rate in the conversion relationship module; A12: individually changing the polishing wheel rotation speed, controlling the polishing wheel to process the test optical element at different polishing gaps, obtaining a removal function volume removal rate at each processing position, and obtaining a fourth conversion relationship between the removal function volume removal rate and the polishing wheel rotation speed in the conversion relationship module; A13: Obtain the first conversion relationship according to the third conversion relationship and the fourth conversion relationship.

6. The magnetorheological polishing method based on polishing wheel speed according to claim 5, characterized in that: In step A4, when the polishing wheel is controlled to move to the current processing position, the current ribbon thickness measured by the machine vision device is compared with the second variable range: If the current ribbon thickness is within the second variable range, there is no need to adjust the current polishing wheel speed; If the current ribbon thickness is not within the second variable range, the current polishing wheel speed needs to be adjusted: If the current ribbon thickness is greater than or equal to the maximum ribbon thickness, adjusting the current polishing wheel speed to the maximum polishing wheel speed; If the current ribbon thickness is less than the maximum ribbon thickness, the current polishing wheel speed is adjusted according to the following formula: ； in, represents the first conversion relationship, Indicates the current ribbon thickness, Indicates the current polishing wheel speed.

7. A magnetorheological polishing method based on liquid pump speed, based on the magnetorheological polishing device with machine vision-based processing speed adjustment according to any one of claims 1 to 3, characterized in that: The following steps are involved: B1: controlling the magnetorheological processing module to process the test optical element, and obtaining the second conversion relationship through the conversion relationship module during the processing; B2: Setting a third variable range of the liquid pump speed and obtaining a fourth variable range corresponding to the ribbon thickness according to the second conversion relationship; setting a maximum liquid pump speed and obtaining a corresponding maximum ribbon thickness according to the second conversion relationship; B3: controlling the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum liquid pump speed; B4: The optical element to be processed is processed in combination with the fourth variable range, the maximum liquid pump rotation speed and the maximum ribbon thickness. During the processing, the real-time control module adjusts the liquid pump rotation speed in real time.

8. The magnetorheological polishing method based on liquid pump speed according to claim 7, characterized in that: Step B1 includes the following steps: B11: Controlling the polishing wheel to process the test optical element at different polishing gaps, calculating the removal function volume removal rate at each processing position, and simultaneously measuring the ribbon thickness at each processing position in real time using the machine vision device, and obtaining a fifth conversion relationship between the removal function volume removal rate and the ribbon thickness in the conversion relationship module; B12: individually changing the liquid pump speed of the liquid pump and controlling the polishing wheel to process the test optical element at different polishing gaps to obtain a removal function volume removal rate at each processing position, and obtaining a sixth conversion relationship between the removal function volume removal rate and the liquid pump speed in the conversion relationship module; B13: Obtain the second conversion relationship according to the fifth conversion relationship and the sixth conversion relationship.

9. The magnetorheological polishing method based on liquid pump speed according to claim 8, characterized in that: In step B4, when the polishing wheel is controlled to move to the current processing position, the current ribbon thickness measured by the machine vision device is compared with the fourth variable range: If the current ribbon thickness is within the fourth variable range, there is no need to adjust the current liquid pump speed; If the current ribbon thickness is not within the fourth variable range, the current liquid pump speed needs to be adjusted: If the current ribbon thickness is greater than or equal to the maximum ribbon thickness, adjusting the current liquid pump speed to the maximum liquid pump speed; If the current ribbon thickness If the thickness is less than the maximum ribbon thickness, the current liquid pump speed is adjusted according to the following formula: in, represents the second conversion relationship, Indicates the current ribbon thickness, Indicates the current liquid pump speed.

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