Grinding device and method for repairing damage to curved surface components

Abstract

The present invention discloses a grinding device and a grinding method for repairing damage to curved surface components, which belongs to the technical field of mechanical processing equipment. The grinding method for repairing damage to curved surface components includes the following steps: S1, hand-eye calibration and tool calibration: obtaining the conversion matrix of the 3D vision system coordinate system relative to the center coordinate system of the end of the robot arm, and obtaining the conversion matrix of the tool coordinate system relative to the center coordinate system of the end of the robot arm; S2, setting the initial state of grinding: using the drag teaching function to set the initial state of the robot arm grinding; S3, grinding path planning: obtaining the point cloud model of the workpiece surface, and obtaining the grinding path point information; S4, robot arm grinding program generation: generating a robot arm grinding motion control program; S5, grinding process. The grinding device and grinding method for repairing damage to curved surface components of the present invention can perform constant force grinding on the irregular surface of the curved surface component to ensure that the surface of the curved surface component is polished more evenly.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical processing equipment, and in particular to a grinding device and a grinding method for repairing damage to curved surface components. Background Art

[0002] Composite materials, due to their exceptional high specific strength, high specific stiffness, and fatigue resistance, are increasingly being used in aviation and aerospace, particularly in critical components such as aircraft wings, fuselages, and radomes. With this increasing use comes increasing maintenance and repair challenges.

[0003] During an aircraft's service life, composite components such as wings, fuselages, and radomes may sustain damage that can affect the aircraft's structural integrity and flight performance, necessitating prompt repair. A common method for repairing these components is patching and bonding. This process involves grinding and removing the damaged area to create a stepped or sloped cavity to be repaired. A patch is then prepared to match the groove to be repaired. The patch is then bonded to the groove using equipment such as a thermal patching machine and auxiliary materials. After curing, the repaired surface is further ground and polished.

[0004] In damage repair work, existing damage repair grinding equipment faces a key problem when facing curved components with irregular surfaces: it is difficult to apply a constant grinding force to the surface of the curved component during the grinding process. This defect directly leads to subsequent problems. Due to the unstable grinding force, the grinding uniformity of the curved component surface is greatly reduced, and the grinding uniformity is closely related to the repair quality of the curved component, which ultimately leads to a serious impact on the repair quality of the curved component. For example, the robot flexible intelligent grinding system based on a six-dimensional force sensor disclosed in Chinese patent application number CN201910524443.3 is composed of a teach pendant, a robot controller, a robot body, a six-dimensional force sensor and a polishing device. Before starting the grinding operation, the operator can use the drag teaching method to delineate the two-dimensional grinding area, and then scan the three-dimensional grinding path through slow simulation. During grinding, the force sensor monitors the relative position and contact force between the grinding device and the polished surface in real time, and the robot controller adjusts the posture of the grinding device based on the monitoring data to complete the operation. However, this system has obvious shortcomings: on the one hand, relying solely on drag-and-drop teaching for path planning is likely to result in a path accuracy that is difficult to achieve the ideal level; on the other hand, when the system is applied to the field of composite material patching and repair, in order to achieve material removal during the grinding of the bonding surface cavity, the force on the grinding contact surface will continue to increase with the increase in grinding depth, and the requirement of constant force grinding cannot be achieved. For example, Chinese patent application number CN201711495033.8 discloses a robot grinding control system and its operating method. The system is equipped with a wired laser sensor for scanning and obtaining the geometric parameters of the workpiece being ground. It is provided with a three-dimensional model construction unit, which is responsible for establishing a three-dimensional model of the workpiece. The grinding area generation unit extracts the three-dimensional model of the grinding area based on the CAD model. The trajectory generation unit formulates the grinding path of the grinding area and the grinding force at each path point. The simulation unit simulates the robot's grinding process according to the grinding path and force in three-dimensional space. There is also a trajectory optimization unit that optimizes the grinding path and force so that the robot controller can control the robot operation based on the optimized data. However, this system is mainly suitable for the surface deburring process of metal parts, and is not suitable for patching and grinding irregular surfaces such as stepped or sloped surfaces on the workpiece surface. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems in the prior art and provide a grinding device and a grinding method for repairing damage to curved components, which can perform constant force grinding on the irregular surface of the curved component to ensure that the surface of the curved component is polished more evenly.

[0006] The present invention provides a grinding device and a grinding method for repairing damage to a curved surface component, comprising the following steps:

[0007] S1. Hand-eye calibration and tool calibration: Use the nine-point method to perform eye-on-hand hand-eye calibration on the 3D vision system to obtain the transformation matrix of the 3D vision system coordinate system relative to the center coordinate system of the robot end arm. Use the six-point method to perform tool calibration on the high-pressure grinder to obtain the transformation matrix of the tool coordinate system relative to the center coordinate system of the robot end arm.

[0008] S2. Setting the initial grinding state: Use the drag-and-drop teaching function to set the initial grinding state of the robot arm;

[0009] S3. Grinding path planning: Scan the workpiece surface using a 3D vision system to obtain a point cloud model of the workpiece surface. Based on the obtained point cloud model and the shape of the pit to be ground on the workpiece, data processing is performed to obtain grinding path point information for the pit;

[0010] S4. Robot arm polishing program generation: Based on the polishing path point information obtained above, combined with the transformation matrix obtained by hand-eye calibration and the transformation matrix obtained by tool calibration, the robot arm polishing path coordinates are calculated to generate the robot arm polishing motion control program;

[0011] S5. Grinding process: Control the robotic arm to perform the grinding process according to the generated robotic arm grinding motion control program.

[0012] Preferably, after the grinding process is completed, the grinding effect of the workpiece is detected. When the grinding effect does not meet the requirements, steps S2-S5 are repeated, or when the grinding motion control program of step S4 is generated, a grinding path planning with multiple cycles is set to continuously grind the workpiece.

[0013] Preferably, when performing hand-eye calibration, the specific steps are: first, install the 3D vision system on the end of the robotic arm, control the robotic arm to drive the 3D vision system to the shooting position to ensure that the nine corner points in the calibration plate of the nine-point method are all within the field of view of the 3D vision system, control the 3D vision system to shoot the image of the calibration plate, record the pixel coordinates of the nine corner points in the calibration plate, and then adjust the end of the robotic arm in sequence to make the 3D vision system reach the nine corner points in the calibration plate, record the coordinates of the robotic arm of the nine corner points, and finally obtain the transformation matrix of the 3D vision system coordinate system relative to the center coordinate system of the robotic arm end.

[0014] Preferably, when performing tool calibration, the specific steps are as follows: select a fixed tip in the workspace, use the drag teaching function of the robot arm controller, control the end of the robot arm to make it coincide with the fixed tip in four different postures, collect the robot arm posture data each time it coincides, record the four collected posture data, and provide a basis for the calculation of tool calibration, then control the end of the robot arm to move the set distance in the positive direction of the x-axis and z-axis of its end center coordinate system in sequence, record the robot arm posture at the two points respectively, and finally run the script of the drag teaching function to obtain the transformation matrix of the tool coordinate system relative to the end center coordinate system of the robot arm.

[0015] Preferably, the specific steps for obtaining accurate grinding path points are as follows: first, the shape model of the pit on the workpiece to be ground needs to be obtained through 3D modeling software, and the shape model is converted into a 3D point cloud of the pit through the 3D model data conversion function of the 3D modeling software; then, the 3D point cloud of the pit and the 3D point cloud of the workpiece surface captured by the 3D vision system are point cloud aligned in the point cloud processing software. The principle of alignment is to align the 3D point cloud of the pit at the position on the workpiece surface that needs to be ground. After the alignment is completed, the 3D point cloud of the workpiece with the pit is obtained, and the 3D coordinates of the 3D point cloud of the pit part have also been converted to the 3D vision system coordinate system; then, the 3D point cloud at the pit is separated by point cloud segmentation in the point cloud processing software, and the 3D point cloud at the separated pit is subjected to point cloud normal vector calculation and point cloud slicing processing to obtain point cloud cross-section lines, and then the obtained point cloud cross-section lines are subjected to point cloud downsampling and point cloud sorting; finally, the different point cloud cross-section lines after downsampling and sorting are planned to obtain grinding path point information for the pit.

[0016] The present invention also provides a grinding device, comprising a grinding machine and a robotic arm, wherein the grinding machine is connected to the end of the robotic arm, and is characterized in that it further comprises:

[0017] a 3D vision system, provided on the robotic arm, for scanning the surface of the workpiece to obtain a point cloud model of the polished workpiece surface;

[0018] a central controller electrically connected to the 3D vision system, the central controller being used to perform data processing based on the acquired point cloud model and the shape of the pit to be ground on the workpiece, obtain grinding path point information for the pit, and calculate the robot arm grinding path coordinates based on the acquired grinding path point information for the pit, thereby generating a robot arm grinding motion control program;

[0019] The robotic arm controller is electrically connected to the robotic arm and the central controller. The robotic arm controller has a drag teaching function. The robotic arm controller can determine the point information of the end of the robotic arm through the drag teaching function. The robotic arm controller is used to control the robotic arm movement according to the generated robotic arm grinding motion control program to grind the surface of the workpiece.

[0020] Preferably, the high-pressure grinding machine is further provided with an automatic tool changing device, the bottom of which is provided with diamond grinding tools of various specifications, the diamond grinding tools having a grinding wheel, and the automatic tool changing device is used to replace the diamond grinding tools connected to the high-pressure grinding machine.

[0021] Preferably, the high-speed grinder is electrically connected to a high-speed grinder driver, and the high-speed grinder driver is used to set the power and speed of the high-speed grinder.

[0022] Preferably, an optical platform is further included, which is arranged below the 3D vision system. A workpiece fixture is provided on the optical platform, which is used to clamp the workpiece. The horizontality of the optical platform is adjustable.

[0023] Preferably, a vacuum cleaner is provided on the optical platform, and the vacuum cleaner comprises a dust hood and a dust collection main unit, the dust collection main unit is connected to the dust hood, and the dust hood is provided above the workpiece fixture.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention provides a grinding method for repairing damaged curved components. The method performs hand-eye calibration and tool calibration through a robotic arm controller to obtain the conversion matrix of the 3D vision system coordinate system relative to the center coordinate system of the robotic arm end, and the conversion matrix of the tool coordinate system relative to the center coordinate system of the robotic arm end. The method also obtains a point cloud model of the surface of the workpiece to be polished, and then plans the grinding path of the high-pressure grinder based on the point cloud model. The central controller then polishes the workpiece according to the grinding path. This method can realize the automation or semi-automation of the excavation and grinding process involved in the repair of composite curved components, and can perform constant force grinding on the irregular surface of the curved component to ensure that the surface of the curved component is polished more evenly. Furthermore, by adopting a robotic arm, the safety, collaboration, and ease of use of the entire device are greatly improved, and the grinding and excavation operation process involved in the repair of composite materials is efficiently realized, reducing the degree of manual participation.

[0026] 2. The polishing tool of the present invention combines the drag-and-teach function of the robotic arm to quickly realize the initial posture positioning of the polishing, uses the 3D vision system to quickly obtain the three-dimensional point cloud model of the polished workpiece surface, and performs data processing on the point cloud model based on the shape of the pit to be polished to obtain accurate polishing path point information, thereby meeting the needs of fast and precise repair and polishing of composite materials.

[0027] 3. The dust collection hood device of the present invention can efficiently absorb waste chips, dust, impurities, etc. generated during the grinding process, and effectively prevent the dispersion and pollution of grinding impurities and dust.

[0028] 4. The entire grinding device of the present invention integrates a dust collection device and a mobile platform, which not only facilitates deployment and adjustment at the maintenance site, but also reduces occupational health hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention.

[0030] Figure 2 It is a structural schematic diagram of the strong grinding mill of the present invention.

[0031] Figure 3 It is a step diagram of the polishing method of the present invention.

[0032] Figure 4 This is a flow chart of the polishing path planning method of the present invention.

[0033] Figure 5 Schematic diagram of the parallel point cloud slicing method of the present invention.

[0034] Figure 6 Schematic diagram of the annular centering point cloud slicing method of the present invention.

[0035] Description of reference numerals:

[0036] 1. Air source, 2. Optical platform, 3. Robotic arm controller, 4. Vacuum host, 5. High-pressure grinding machine driver, 6. Mouse, 7. Display, 8. Keyboard, 9. Host computer, 10. Workpiece, 11. Workpiece fixture, 12. Dust hood, 13. High-pressure grinding machine, 14. Fixture, 15. 3D vision system, 16. Automatic tool changer, 17. Diamond grinding tool, 18. Robotic arm, 19. Air supply line. DETAILED DESCRIPTION

[0037] The following is combined with Figures 1-6 , the specific embodiments of the present invention are described in detail, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] like Figures 1-6As shown, the present invention provides a grinding device for repairing damage to curved surface components, including an optical platform 2, a workpiece fixture 11, a strong grinder driver 5, a strong grinder 13 and a robotic arm 18, wherein the strong grinder 13 is connected to the end of the robotic arm 18, and further comprising: a 3D vision system 15, a central controller and a robotic arm controller 3, wherein the 3D vision system 15 is provided on the robotic arm 18, and the 3D vision system 15 is used to scan the surface of the workpiece 10 to obtain a point cloud model of the surface of the polished workpiece 10; the central controller is electrically connected to the 3D vision system 15, and the central controller is used to scan the surface of the workpiece 10 according to the obtained point cloud model and based on the workpiece 10. The shape of the pit to be polished on the workpiece 10 is processed data, the polishing path point information for the pit is obtained, and the polishing path coordinates of the robot arm 18 are calculated based on the acquired polishing path point information for the pit, thereby generating a polishing motion control program for the robot arm 18; the robot arm controller 3 is electrically connected to the robot arm 18 and the central controller, and the robot arm controller 3 has a drag teaching function. The robot arm controller 3 can determine the point information of the end of the robot arm 18 through the drag teaching function, and the robot arm controller 3 is used to control the movement of the robot arm 18 according to the generated robot arm 18 polishing motion control program to polish the surface of the workpiece 10.

[0039] The working principle of the above embodiment is briefly described below:

[0040] The central controller includes a host computer 9 and a human-machine operation module consisting of a display screen 7, keyboard 8, and mouse 6. The central controller enables the operator to control the entire grinding system. The 3D vision system 15 is a binocular structured light camera. The host computer 9 establishes communication links with the robot arm controller 3, the binocular structured light camera, the high-pressure grinding machine driver 5, and the vacuum cleaner 4 to implement control functions.

[0041] The optical platform 2 is equipped with handles on the sides, casters and adjustable support feet at the bottom to meet the needs of changing workstations. When changing workstations, the support feet are adjusted to retract, the casters are released, and the entire device is moved using the handles. When performing operations, the support feet are adjusted to lift the optical platform 2 and calibrate its levelness to ensure that the entire polishing device is stably placed.

[0042] The robot arm 18 is a six-axis light robot arm 18 , which clamps the grinding machine 13 through the fixture 14 .

[0043] The 3D vision system 15 uses a binocular structured light camera.

[0044] When using this device:

[0045] Adjust the support legs to make the optical platform 2 level, and use a spirit level to calibrate the levelness in multiple places to ensure the stability of the entire device. Connect the external power supply and air supply lines, start the robot arm 18 and the binocular structured light camera through the human-machine operation module, and adjust the exposure, depth range and other parameters of the binocular structured light camera; according to the condition of the workpiece 10, set the working parameters of the strong grinder 13 through the strong grinder driver. Use the nine-point method to perform eye-on-hand hand-eye calibration for the binocular structured light camera. Install the binocular structured light camera at the end of the robot arm 18, control the robot arm 18 to make the binocular structured light camera reach the appropriate position to capture the image of the calibration plate, and record the pixel coordinates of the nine corner points determined by the nine-point method; adjust the end of the robot arm 18 to reach the corner points of the calibration plate, and record the coordinates of the corner points in the central coordinate system of the end of the robot arm 18; execute the script to obtain the transformation matrix of the binocular structured light camera coordinate system relative to the central coordinate system of the end of the robot arm 18. A fixed tip is selected in the workspace. The drag-and-teach function of the robot controller 3 is used to manipulate the end of the robot arm 18 so that it coincides with the fixed tip in four different positions. Each time the position data of the robot arm 18 coincides, the position data collected is recorded. These four collected position data provide a basis for the calculation of tool calibration. The end of the robot arm 18 is then controlled to move a set distance in the positive direction of the x-axis and z-axis of its end center coordinate system in sequence. The position of the robot arm 18 at each point is recorded. Finally, the script for the drag-and-teach function is run to execute the script to obtain the transformation matrix of the tool coordinate system relative to the center coordinate system of the end of the robot arm 18. Install the workpiece 10 to be polished: The workpiece fixture 11 can be prepared by machining or 3D printing. After obtaining the workpiece fixture 11, the workpiece 10 is placed in a position convenient for polishing and fixed with the workpiece fixture 11. The workpiece 10 can be connected to the workpiece fixture 11 by screws according to its shape. The workpiece 10 is placed in the center of the optical platform 2. Initial grinding state setting: Use the drag-and-drop teaching function of the robot arm 18 to set the initial grinding state. It is required that the binocular structured light camera can capture the entire image of the workpiece 10 and that the robot arm 18 is not prone to motion singularities when executing the grinding program. Grinding path planning: Use the 3D vision system 15 to scan the surface of the workpiece 10 to obtain a point cloud model of the surface of the workpiece 10. The central controller processes the obtained point cloud model and the shape of the pit to be ground on the workpiece 10 to obtain accurate grinding path point information. The specific steps are as follows: Figure 4As shown: first, it is necessary to obtain the shape model of the pit on the workpiece 10 to be polished through the 3D modeling software, and convert it into a point cloud format file through the 3D model data conversion function of the 3D modeling software, and then perform point cloud registration on the 3D point cloud of the pit and the 3D point cloud of the surface of the workpiece 10 photographed by the 3D vision system 15 in the point cloud processing software. The principle of registration is to align the 3D point cloud of the pit at the position on the surface of the workpiece 10 that needs to be polished. After the registration is completed, the 3D point cloud of the workpiece 10 with the pit is obtained, and the 3D coordinates of the 3D point cloud of the pit part have also been converted to the coordinate system of the 3D vision system 15; then, in the point cloud processing software, the 3D point cloud at the pit is separated by point cloud segmentation, and the 3D point cloud at the separated pit is subjected to point cloud normal vector calculation and point cloud slicing processing to obtain point cloud cross-section lines. Slicing processing refers to the use of parallel or circular centering (such as Figure 5 and Figure 6 The point cloud is sliced ​​by a cutting plane (as shown) to obtain the point cloud section line at the intersection of the cutting plane and the point cloud. The spacing or angle between each cutting plane during point cloud slicing is determined by the actual process parameters. The obtained point cloud section line is then subjected to point cloud downsampling and point cloud sorting, wherein the degree of point cloud downsampling is determined by the density of the final required path points. Finally, a reasonable polishing order is used to plan the different point cloud section lines after downsampling and sorting to obtain the polishing path point information for the pits on the entire workpiece 10. The polishing program of the robot arm 18 is generated: based on the polishing path point information in the binocular structured light camera coordinate system, the normal vector is converted into Euler angle to process the path point information. Combined with the hand-eye calibration matrix and the tool calibration matrix, the polishing path posture of the robot arm 18 is calculated to generate a polishing motion control program. Start the high-pressure grinder 13 and control the robot arm 18 to perform the polishing process according to the generated program. The program needs to be executed twice or more to eliminate the track interval and burrs. After the polishing is completed, turn off the high-pressure grinder 13 and the robot arm 18, and clean the debris in the polishing area. Remove the workpiece 10 and inspect the grinding effect visually or with professional equipment.

[0046] The present invention provides a grinding device for repairing damage to curved components, which can realize the automation or semi-automation of the excavation and grinding process involved in the repair of composite material curved components, and can perform constant force grinding on the irregular surface of the curved component to ensure that the surface of the curved component is polished more evenly.

[0047] As a preferred solution, Figure 1 and Figure 2 As shown, the strong grinding machine 13 is also provided with an automatic tool changing device 16, and the bottom of the automatic tool changing device 16 is provided with diamond grinding tools 17 of various specifications. The diamond grinding tool 17 has a grinding wheel, and the automatic tool changing device 16 is used to replace the diamond grinding tool 17 connected to the strong grinding machine 13.

[0048] By setting up an automatic tool changing device 16, the automatic tool changing device 16 is controlled to change the tool of the grinding machine 13 according to the structure of the surface of the workpiece 10 and the grinding requirements, and replace the diamond grinding tools 17 of different specifications to meet the grinding requirements of different process parameters.

[0049] As a preferred solution, Figure 1 and Figure 2 As shown, the grinding machine 13 is electrically connected to a grinding machine driver 5, which is used to set the power and speed of the grinding machine 13. By setting the power and speed of the grinding machine 13 through the grinding machine driver 5, the grinding parameters of the pit can be adjusted in time according to the shape of the pit, thereby further improving the grinding quality of the entire grinding device.

[0050] As a preferred solution, Figure 1 and Figure 2 As shown, the apparatus further includes an optical platform 2, which is disposed below the 3D vision system 15. A workpiece fixture 11 is provided on the optical platform 2 for clamping the workpiece 10. The level of the optical platform 2 is adjustable. By providing the workpiece fixture 11, when polishing the workpiece 10, the optical platform 2 is first used to adjust the posture of the workpiece fixture 11. The workpiece fixture 11 is then used to clamp the workpiece 10, securing the workpiece 10 in a suitable posture for polishing. Furthermore, the workpiece fixture 11 prevents the workpiece 10 from shaking during polishing, thereby ensuring the polishing quality of the entire polishing apparatus.

[0051] As a preferred solution, Figure 1 and Figure 2 As shown, a vacuum cleaner is provided on the optical platform 2, comprising a dust hood 12 and a main unit 4. The main unit 4 is in communication with the dust hood 12, and the dust hood 12 is positioned above the workpiece fixture 11. The dust hood 12 pipeline is fixed to the side of the optical platform 2, with the dust hood 12 close to the surface of the workpiece 10. The main unit 4 is started and mounted on the bottom support plate of the optical platform 2. The dust hood 12 is positioned above the workpiece fixture 11, i.e., above the polishing area of ​​the workpiece 10. Composite debris generated during the polishing process can be cleaned promptly to prevent dust from escaping and to avoid debris accumulation that would hinder the normal movement of the grinding machine 13.

[0052] As a preferred solution, Figure 1As shown, the grinding mill 13 is connected to an air control circuit, which includes an air source 1 and an air supply line 19. One end of the air supply line 19 is connected to the air source 1, and the other end is connected to the grinding mill 13. The air supply line 19 is equipped with an oil mist separator, a water droplet separator, a solenoid valve, a regulating valve, and a throttle valve. The air source 1 of this device is an air compressor. The air control circuit, through the cooperation of various pneumatic components within it, clamps the diamond grinding tool 17 and automatically changes the tool of the automatic tool changer 16.

[0053] The present invention also provides a method for grinding using a grinding device for repairing damage to a curved surface component, comprising the following steps:

[0054] S1. Hand-eye calibration and tool calibration: Use the nine-point method to perform eye-on-hand hand-eye calibration on the 3D vision system 15 to obtain the transformation matrix of the 3D vision system 15 coordinate system relative to the center coordinate system of the end of the robot arm 18. Use the six-point method to perform tool calibration on the grinding machine 13 to obtain the transformation matrix of the tool coordinate system relative to the center coordinate system of the end of the robot arm 18.

[0055] S2. Setting the initial grinding state: using the drag-and-drop teaching function to set the initial grinding state of the robot arm 18;

[0056] S3. Grinding path planning: Scan the surface of the workpiece 10 using the 3D vision system 15 to obtain a point cloud model of the surface of the workpiece 10. Based on the obtained point cloud model and the shape of the pit to be ground on the workpiece 10, data processing is performed to obtain grinding path point information for the pit;

[0057] S4. Generating a grinding program for the robot arm 18: Based on the grinding path point information obtained above, combined with the transformation matrix obtained by the hand-eye calibration and the transformation matrix obtained by the tool calibration, the grinding path coordinates of the robot arm 18 are calculated to generate a grinding motion control program for the robot arm 18;

[0058] S5, grinding process: controlling the robot arm 18 to perform the grinding process according to the generated robot arm 18 grinding motion control program.

[0059] As a preferred solution, Figure 3 As shown, after the grinding process is completed, the grinding effect of the workpiece 10 is detected. When the grinding effect does not meet the requirements, the steps S2-S5 are repeated, or when the grinding motion control program of the step S4 is generated, a grinding path planning with multiple cycles is set to continuously grind the workpiece 10.

[0060] As a preferred solution, Figure 3As shown, when performing hand-eye calibration, the specific steps are: first, the 3D vision system 15 is installed at the end of the robotic arm 18, and the robotic arm 18 is controlled to drive the 3D vision system 15 to the shooting position to ensure that the nine corner points in the calibration plate of the nine-point method are all located within the field of view of the 3D vision system 15, and the 3D vision system 15 is controlled to shoot the image of the calibration plate, and the pixel coordinates of the nine corner points in the calibration plate are recorded, and then the end of the robotic arm 18 is adjusted in sequence to make the 3D vision system 15 reach the nine corner points in the calibration plate, and the coordinates of the robotic arm 18 of the nine corner points are recorded, and finally, the transformation matrix of the 3D vision system 15 coordinate system relative to the center coordinate system of the end of the robotic arm 18 is obtained.

[0061] As a preferred solution, Figure 3 As shown, when performing tool calibration, the specific steps are as follows: select a fixed tip in the workspace, use the drag teaching function of the robot arm controller 3, control the end of the robot arm 18 to make it coincide with the fixed tip in four different postures, collect the posture data of the robot arm 18 each time it coincides, record the posture data collected four times, and provide a basis for the calculation of tool calibration, then control the end of the robot arm 18 to move the set distance in sequence along the positive direction of the x-axis and z-axis of the center coordinate system of its end, record the posture of the robot arm 18 at two points respectively, and finally run the script of the drag teaching function to obtain the transformation matrix of the tool coordinate system relative to the center coordinate system of the end of the robot arm 18.

[0062] As a preferred solution, Figure 4 As shown, the specific steps for obtaining accurate grinding path points are as follows: first, the shape model of the pit on the workpiece 10 to be ground needs to be obtained through the 3D modeling software, and the 3D model data conversion function of the 3D modeling software is used to convert the shape model into a 3D point cloud of the pit; then, in the point cloud processing software, the 3D point cloud of the pit and the 3D point cloud of the surface of the workpiece 10 photographed by the 3D vision system 15 are point cloud registered. The principle of registration is to register the 3D point cloud of the pit at the position on the surface of the workpiece 10 that needs to be polished. After completing the registration, the 3D point cloud with The three-dimensional point cloud of the workpiece 10 with the pit is obtained, and the three-dimensional coordinates of the three-dimensional point cloud of the pit have also been converted into the coordinate system of the 3D vision system 15; then the three-dimensional point cloud at the pit is separated by point cloud segmentation in the point cloud processing software, and the point cloud normal vector calculation and point cloud slicing processing are performed on the three-dimensional point cloud at the separated pit to obtain the point cloud section line, and then the obtained point cloud section line is point cloud down-sampled and point cloud sorted; finally, the different point cloud section lines after down-sampling and sorting are planned to obtain the grinding path point information for the pit.

[0063] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A grinding method for repairing damage to a curved surface component, characterized in that: The following steps are involved: S1. Hand-eye calibration and tool calibration: Use the nine-point method to perform eye-on-hand hand-eye calibration on the 3D vision system (15) to obtain the transformation matrix of the 3D vision system (15) coordinate system relative to the end center coordinate system of the manipulator (18). Use the six-point method to perform tool calibration on the grinding machine (13) to obtain the transformation matrix of the tool coordinate system relative to the end center coordinate system of the manipulator (18). S2. Setting the initial grinding state: using the drag-and-drop teaching function to set the initial grinding state of the robot arm (18); S3, grinding path planning: using a 3D vision system (15) to scan the surface of the workpiece (10), obtaining a point cloud model of the surface of the workpiece (10), performing data processing based on the obtained point cloud model and the shape of the pit to be ground on the workpiece (10), and obtaining grinding path point information for the pit; S4, generating a grinding program for the robot arm (18): calculating the grinding path coordinates of the robot arm (18) based on the grinding path point information obtained above, combined with the conversion matrix obtained by the hand-eye calibration and the conversion matrix obtained by the tool calibration, to generate a grinding motion control program for the robot arm (18); S5, grinding process: controlling the robot arm (18) to perform the grinding process according to the generated robot arm (18) grinding motion control program; When performing hand-eye calibration, the specific steps are as follows: first, the 3D vision system (15) is installed on the end of the robotic arm (18), the robotic arm (18) is controlled to drive the 3D vision system (15) to reach the shooting position to ensure that the nine corner points in the calibration plate of the nine-point method are all located within the field of view of the 3D vision system (15), the 3D vision system (15) is controlled to shoot the image of the calibration plate, the pixel coordinates of the nine corner points in the calibration plate are recorded, and then the end of the robotic arm (18) is adjusted in sequence to make the 3D vision system (15) reach the nine corner points in the calibration plate, the coordinates of the robotic arm (18) of the nine corner points are recorded, and finally, the transformation matrix of the coordinate system of the 3D vision system (15) relative to the central coordinate system of the end of the robotic arm (18) is obtained; When performing tool calibration, the specific steps are as follows: select a fixed tip in the workspace, use the drag teaching function of the robot controller (3), control the end of the robot arm (18) to make it coincide with the fixed tip in four different postures, collect the posture data of the robot arm (18) each time it coincides, record the posture data collected four times, and provide a basis for the calculation of tool calibration, then control the end of the robot arm (18) to move the set distance in the positive direction of the x-axis and z-axis of the center coordinate system of its end, record the posture of the robot arm (18) at two points respectively, and finally run the script of the drag teaching function to obtain the transformation matrix of the tool coordinate system relative to the center coordinate system of the robot arm (18); The specific steps for obtaining accurate grinding path points are as follows: first, the shape model of the pit on the workpiece (10) to be ground needs to be obtained through the three-dimensional modeling software, and the shape model is converted into a three-dimensional point cloud of the pit through the three-dimensional model data conversion function of the three-dimensional modeling software; then, the three-dimensional point cloud of the pit and the three-dimensional point cloud of the surface of the workpiece (10) photographed by the 3D vision system (15) are aligned in the point cloud processing software. The principle of alignment is to align the three-dimensional point cloud of the pit at the position on the surface of the workpiece (10) that needs to be ground. After the alignment is completed, the point cloud with the pit is obtained. The three-dimensional point cloud of the workpiece (10) at the pit is obtained, and the three-dimensional coordinates of the three-dimensional point cloud at the pit are also converted into the coordinate system of the 3D vision system (15); then, the three-dimensional point cloud at the pit is separated by point cloud segmentation in the point cloud processing software, and the point cloud normal vector calculation and point cloud slicing processing are performed on the three-dimensional point cloud at the separated pit to obtain the point cloud section line, and then the obtained point cloud section line is subjected to point cloud downsampling and point cloud sorting; finally, the different point cloud section lines after downsampling and sorting are planned to obtain the grinding path point information for the pit.

2. The method for repairing damage to a curved surface component according to claim 1, wherein: After the polishing process is completed, the polishing effect of the workpiece (10) is detected. When the polishing effect does not meet the requirements, the steps S2-S5 are repeatedly executed, or when the polishing motion control program of step S4 is generated, a polishing path planning with multiple cycles is set to continuously polish the workpiece (10).

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