Casting grinding dynamic error compensation method, system and device and medium

Abstract

The invention discloses a casting grinding dynamic error compensation method, system and device and a medium, and the method comprises the steps that the ideal pose of an electric spindle is determined, and the electric spindle is controlled by an industrial robot to grind a target casting according to the ideal pose; acquiring image information of the calibration plate, and positioning the calibration plate according to the image information to obtain first pose information of the calibration plate; determining second pose information of the motorized spindle according to the first pose information; the pose error of the motorized spindle is determined according to the second pose information and the ideal pose, and the pose of the motorized spindle is controlled through the industrial robot according to the pose error; wherein the calibration plate is fixedly connected with the motorized spindle. The posture change dynamic state of the motorized spindle is tracked in real time in a high-precision mode through the binocular camera and the calibration plate, precision compensation and vibration control are conducted through the industrial robot, the machining precision and the grinding quality are improved, and the method can be widely applied to the technical field of workpiece grinding.

Description

Technical Field

[0001] The present invention relates to the technical field of workpiece grinding, and particularly to a method, system, device and medium for compensating dynamic errors in casting grinding. Background Art

[0002] Generally, industrial robots can only simply repeat the same actions, have no tactile sense, and cannot adapt to changes in the specifications and dimensions of castings. They can also handle workpieces with complex structures and workpieces with scattered burrs. Moreover, robots are programmable, and the introduction of flexible force control devices only requires changing tooling fixtures and can be completed by switching sequences. This makes the equipment more flexible and more suitable for the current needs of enterprises. The robot deburring solution can reduce the labor intensity of workers or directly eliminate workers, reduce the inconsistency of processing quality, improve production efficiency, and improve the factory working environment. These advantages are obvious, and even though the equipment investment cost is slightly high, it is increasingly accepted by enterprises.

[0003] With the development of robot force control technology, the use of floating mechanisms and tools can flexibly remove burrs like a human hand sliding over the burrs of a workpiece, effectively avoiding damage to the tool and the workpiece and absorbing errors in various aspects such as the workpiece and positioning. The force control software consists of two advanced core functions. One is the pressure control function, which can keep the pressure of the tool on the workpiece constant when the robot grinds and polishes the casting. The other is the variable speed control function, which can continuously control the operation speed when the robot deburrs and removes flash from the surface or parting line of the casting, and can automatically decelerate when encountering a large protrusion.

[0004] However, the floating tool can only control the force at the end of the tool and only has measurements in the axial direction of the electric spindle. It cannot monitor the real-time grinding situation, cannot detect vibrations during the grinding process and feedback them to the robot control system to achieve high-precision and smooth grinding control. Summary of the Invention

[0005] The purpose of the present invention is to solve at least to some extent one of the technical problems existing in the prior art.

[0006] To this end, an object of an embodiment of the present invention is to provide a method for compensating dynamic errors in casting grinding, which can dynamically track the pose change of the electric spindle in real time and with high precision through a binocular camera and a calibration plate, and perform precision compensation and vibration control through an industrial robot to improve the processing quality.

[0007] Another object of an embodiment of the present invention is to provide a system for compensating dynamic errors in casting grinding.

[0008] To achieve the above technical objectives, the technical solutions adopted in the embodiments of the present invention include:

[0009] In a first aspect, an embodiment of the present invention provides a method for compensating dynamic errors in casting grinding, including:

[0010] Calculating the ideal pose of the electric spindle;

[0011] Controlling the electric spindle to grind the target casting according to the ideal pose by an industrial robot;

[0012] Obtaining the image information of the calibration plate;

[0013] Positioning the calibration plate according to the image information to obtain the first pose information of the calibration plate;

[0014] Determining the second pose information of the electric spindle according to the first pose information;

[0015] Controlling the pose of the electric spindle by an industrial robot according to the ideal pose and the second pose information;

[0016] Wherein, the calibration plate and the electric spindle are connected by a fixture.

[0017] Further, the image information includes the pixel coordinate system coordinates of the feature points of the calibration plate image, and obtaining the image information of the calibration plate includes:

[0018] Obtaining the calibration plate image by a binocular camera;

[0019] Detecting the calibration plate image by a feature point detection algorithm to obtain the pixel coordinate system coordinates of the feature points;

[0020] Wherein, the binocular camera is installed above the calibration plate.

[0021] Further, positioning the calibration plate according to the image information to obtain the first pose information of the calibration plate includes:

[0022] Determining the world coordinate system coordinates of the feature points according to the pixel coordinate system coordinates of the feature points;

[0023] Determining the first pose information according to the world coordinate system coordinates of the feature points.

[0024] Further, determining the world coordinate system coordinates of the feature points according to the pixel coordinate system coordinates of the feature points includes:

[0025] Calibrating the binocular camera to obtain the internal parameter information and external parameter information of the binocular camera;

[0026] Determining the image plane coordinate system coordinates of the feature points according to the pixel coordinate system coordinates of the feature points and the internal parameter information;

[0027] Determine the camera coordinate system coordinates of the feature point according to the image plane coordinate system coordinates of the feature point and the projection relationship of the binocular camera;

[0028] Determine the world coordinate system coordinates of the feature point according to the camera coordinate system coordinates of the feature point and the external parameter information.

[0029] Further, the determining the first pose information according to the world coordinate system coordinates of the feature point includes:

[0030] Obtain the world coordinate system coordinates of at least three of the feature points;

[0031] Calculate the six-degree-of-freedom pose of the calibration plate according to the world coordinate system coordinates of at least three of the feature points to obtain the first pose information.

[0032] Further, the determining the second pose information of the electric spindle according to the first pose information includes:

[0033] Obtain the relative pose relationship between the calibration plate and the electric spindle;

[0034] Transform the first pose information according to the relative pose relationship to obtain the second pose information.

[0035] Further, the relative pose relationship includes the displacement relationship and the rotation relationship of the electric spindle relative to the calibration plate. The transforming the first pose information according to the relative pose relationship to obtain the second pose information includes:

[0036] Determine the displacement relationship and the rotation relationship according to the relative pose relationship;

[0037] Transform the first pose information according to the displacement relationship and the rotation relationship to obtain the second pose information.

[0038] In a second aspect, an embodiment of the present invention provides a dynamic error compensation system for casting grinding, including:

[0039] A grinding module, configured to determine an ideal pose of an electric spindle, and control the electric spindle to grind a target casting according to the ideal pose by an industrial robot;

[0040] A pose determination module, configured to obtain image information of a calibration plate, and perform positioning on the calibration plate according to the image information to obtain the first pose information of the calibration plate;

[0041] A pose conversion module, configured to determine the second pose information of the electric spindle according to the first pose information;

[0042] An error compensation module, configured to determine the pose error of the electric spindle according to the second pose information and the ideal pose, and control the pose of the electric spindle by an industrial robot according to the pose error;

[0043] Wherein, the calibration plate is fixedly connected to the electric spindle.

[0044] In a third aspect, an embodiment of the present invention provides a device, including:

[0045] At least one processor;

[0046] At least one memory, configured to store at least one program;

[0047] When the at least one program is executed by the at least one processor, the at least one processor implements a dynamic error compensation method for casting grinding as described above.

[0048] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, in which a program executable by a processor is stored, and the program executable by the processor is used to execute a dynamic error compensation method for casting grinding as described above when executed by the processor.

[0049] The advantages and beneficial effects of the present invention will be partially given in the following description, partially will become obvious from the following description, or will be understood through the practice of the present invention:

[0050] In the embodiment of the present invention, the image information of the calibration plate is obtained by a binocular camera, the three-dimensional spatial position of the calibration plate can be calculated, the pose change of the electric spindle can be tracked dynamically in real time with high precision, the vibration during the grinding process can be measured, and the real-time pose is fed back to the industrial robot control system for precision compensation and vibration control. It can provide six-degree-of-freedom pose change information to achieve high-precision error compensation, with low hardware cost and fast data processing speed, which can meet the requirements of real-time error compensation and improve the grinding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the steps of a dynamic error compensation method for casting grinding provided by an embodiment of the present invention;

[0052] Figure 2 It is a schematic diagram of an implementation scenario of a dynamic error compensation method for casting grinding provided by an embodiment of the present invention;

[0053] Figure 3 It is a schematic diagram of a dynamic error compensation system for casting grinding provided by an embodiment of the present invention;

[0054] Figure 4 It is a schematic diagram of the structure of a computer device provided by an embodiment of the present invention.

[0055] The reference numerals are: 1: binocular camera; 2: industrial robot; 3: calibration plate; 4: electric spindle; 5: casting. Detailed implementation manners

[0056] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention. For the step numbers in the following embodiments, they are only set for the convenience of description and illustration, and no limitation is imposed on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0057] In the description of the present invention, the meaning of "a plurality of" is two or more. If the first and second are described, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features. In addition, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention.

[0058] Casting grinding is a machining task with relatively high precision requirements. During the surface treatment process of high-precision castings, any tiny error will affect the final machining quality. The sources of errors mainly include the trajectory error of the industrial robot and the vibration error at the end of the tool.

[0059] The main reason for the trajectory error is that although the industrial robot can move according to the preset trajectory, due to factors such as the elastic deformation of the mechanical structure, part precision, or joint clearance, the execution trajectory of the industrial robot may deviate from the theoretical trajectory; the main reason for the vibration error is that during the grinding process, due to the high-speed rotation of the electric spindle and the unevenness of the workpiece surface, it may cause the grinding tool to generate tiny vibrations, affecting the machining quality.

[0060] Currently, the common error compensation methods in the industry mainly include:

[0061] 1) Floating tool compensation

[0062] The principle of the floating tool is to add a floating mechanism at the end of the tool (such as a floating tool with a spring installed), so that the tool can move freely within a certain range, enabling the grinding tool to remove burrs flexibly like a human hand sliding over the workpiece burrs, being able to adapt to the tiny changes on the workpiece surface and absorb errors in various aspects such as vibration and positioning.

[0063] 2) Force control error compensation

[0064] This method installs a force sensor at the end of the tool. By detecting the pressure between the tool and the workpiece, the pressure data is transmitted to the force control software for analysis, and the grinding pressure is adjusted in real time, so as to keep the pressure of the tool on the workpiece unchanged all the time.

[0065] However, the above traditional methods have the following deficiencies:

[0066] 1) The compensation method based on the floating tool can only perform error compensation in one-dimensional direction (usually axial compensation), with general compensation accuracy and limited adaptability, and the compensation effect is poor when facing castings with complex shapes.

[0067] 2) The error compensation based on the force sensor requires a relatively complex system, with high calculation cost, large influence by environmental interference, and general real-time performance.

[0068] In order to make up for the compensation of the traditional method, the embodiment of the present invention proposes a dynamic error compensation method for casting grinding. By obtaining the image information of the calibration board through a binocular camera, the three-dimensional spatial position of the calibration board can be calculated, the pose change of the electric spindle can be dynamically tracked in real time with high precision, the vibration during the grinding process can be measured, and the real-time pose is fed back to the industrial robot control system for precision compensation and vibration control, which has the following advantages:

[0069] 1) High-precision six-degree-of-freedom error measurement: Compared with traditional technologies such as floating tools, the embodiment of the present invention can provide six-degree-of-freedom pose change information to achieve high-precision error compensation, is applicable to complex grinding scenarios, effectively measures and compensates the robot trajectory error and the vibration error at the tool end, and improves the grinding quality.

[0070] 2) Low cost and high real-time performance: Compared with error measurement and positioning methods such as force control error compensation, structured light three-dimensional cameras or laser scanners, the embodiment of the present invention has low hardware cost and fast data processing speed, and can meet the requirements of real-time error compensation.

[0071] Figure 1 For the step schematic diagram of a dynamic error compensation method for casting grinding provided by the embodiment of the present invention, refer to Figure 1 , the embodiment of the present invention provides a dynamic error compensation method for casting grinding, including:

[0072] S101. Determine the ideal pose of the electric spindle, and control the electric spindle to grind the target casting according to the ideal pose through an industrial robot;

[0073] S102. Obtain the image information of the calibration board, and locate the calibration board according to the image information to obtain the first pose information of the calibration board;

[0074] S103. Determine the second pose information of the electric spindle according to the first pose information;

[0075] S104. Determine the pose error of the electric spindle based on the second pose information and the ideal pose, and control the pose of the electric spindle by the industrial robot according to the pose error;

[0076] Wherein, the calibration plate is fixedly connected to the electric spindle.

[0077] In some alternative embodiments, the image information includes the pixel coordinate system coordinates of the feature points of the calibration plate image. Obtaining the image information of the calibration plate includes:

[0078] A. Obtain the calibration plate image through a binocular camera;

[0079] B. Detect the calibration plate image through a feature point detection algorithm to obtain the pixel coordinate system coordinates of the feature points;

[0080] Wherein, the binocular camera is installed above the calibration plate.

[0081] Specifically, in this embodiment, the intersection points of the checkerboard of the calibration plate image obtained by the binocular camera have obvious gradient changes. The Harris equiangular point detection algorithm can be used to calculate the gradient change of the local window to detect the corner points and thus select the feature points. Determining the three-dimensional pose of a rigid body in space requires at least three non-collinear points, and the selected feature points should be evenly distributed to improve the stability of pose calculation. The center point, upper right corner point and lower left corner point of the calibration plate can be selected as the feature points to obtain the position information of these three feature points in the image, that is, their coordinates in the pixel coordinate system. Based on this coordinate, calculate the position information (X, Y, Z) and rotation information (A, B, C) of the calibration plate, so as to determine the six-degree-of-freedom pose information of the calibration plate.

[0082] This process not only provides the accurate pose of the calibration plate in the camera coordinate system, but also through calculation, can map these position information to the world coordinate system, providing key data support for the subsequent pose calculation, error measurement and dynamic error compensation of the electric spindle. Through this method, we can obtain high-precision position information in real time during the casting grinding process, ensuring the grinding accuracy and processing quality.

[0083] Figure 2 For the implementation scenario schematic diagram of a casting grinding dynamic error compensation method provided by an embodiment of the present invention, refer to Figure 2, in this embodiment, the binocular camera is used to capture images of the calibration board, providing raw data for calculating its pose information; the calibration board is a ceramic board in the shape of a checkerboard, which can provide a stable and recognizable reference benchmark for the binocular camera, facilitating the detection of feature points such as the central origin and corner points of the checkerboard from the image data obtained by the binocular camera; the calibration board is fixed on the electric spindle through a special fixture, rigidly connected to the electric spindle, and its movement is synchronized with the electric spindle, so that the pose of the calibration board obtained from the image data can indirectly reflect the actual pose of the electric spindle; the electric spindle, as the actuator of the grinding tool, processes the surface of the casting; the movement of the electric spindle is controlled by an industrial robot, and the grinding process is compensated for accuracy and vibration controlled according to the measured error information.

[0084] In this embodiment, according to the target requirements and processing standards, the target position and orientation that the electric spindle should be in during the grinding process are determined to obtain the ideal pose of the electric spindle. Then, the deviation between the actual pose of the electric spindle measured through the calibration board and the ideal pose is calculated to obtain error information, and this error information is transmitted to the industrial robot to adjust the movement trajectory of the industrial robot, thereby compensating for the pose deviation of the electric spindle. Through this error compensation, the industrial robot can adjust the movement of the electric spindle according to the deviation between the ideal pose and the actual pose of the electric spindle, so as to keep the actual pose of the electric spindle close to the ideal pose as much as possible during the grinding process, thereby improving the grinding accuracy and ensuring the processing quality.

[0085] It can be realized that in this embodiment, the pose of the calibration board is tracked in real time through the binocular camera, and then the dynamic pose change of the electric spindle is determined. The industrial robot can adjust the trajectory in real time according to the pose change situation to ensure that the error during the grinding process is minimized and the processing quality is improved. Compared with the traditional floating tool compensation scheme, the six-degree-of-freedom pose information of the electric spindle can be obtained, and all-round error compensation can be achieved to ensure the grinding accuracy. Compared with schemes such as force sensors and structured light three-dimensional cameras, the cost is lower, the processing speed is faster, and dynamic real-time compensation can be realized.

[0086] In some alternative embodiments, the calibration board is positioned according to the image information to obtain the first pose information of the calibration board, including:

[0087] S1021. Determine the world coordinate system coordinates of the feature points according to the pixel coordinate system coordinates of the feature points;

[0088] S1022. Determine the first pose information according to the world coordinate system coordinates of the feature points.

[0089] In some alternative embodiments, determining the world coordinate system coordinates of the feature points according to the pixel coordinate system coordinates of the feature points includes:

[0090] S10211. Calibrate the binocular camera to obtain the internal parameter information and external parameter information of the binocular camera;

[0091] S10212. Determine the image plane coordinate system coordinates of the feature points based on the pixel coordinate system coordinates of the feature points and the internal parameter information.

[0092] S10213. Determine the camera coordinate system coordinates of the feature points based on the image plane coordinate system coordinates of the feature points and the projection relationship of the binocular camera.

[0093] S10214. Determine the world coordinate system coordinates of the feature points based on the camera coordinate system coordinates of the feature points and the external parameter information.

[0094] Specifically, in this embodiment, it is necessary to calibrate the binocular camera to obtain the internal parameter information and the external parameter information.

[0095] The internal parameter information is used to describe the optical characteristics of the camera itself and can be represented by the camera internal parameter matrix K:

[0096]

[0097] The internal parameter matrix parameters include the focal length f x and f y , the intersection point (c x , c y ) of the camera optical axis on the image, and the distortion parameter s for correcting the lens distortion. The values of the parameters in the internal parameter matrix can be obtained by the Zhang Zhengyou checkerboard calibration method.

[0098] The external parameter information is used to describe the position and orientation of the camera in the world coordinate system, including the rotation matrix describing the rotation relationship of the camera coordinate system relative to the world coordinate and the translation vector describing the displacement relationship of the camera coordinate system relative to the world coordinate. Its value can be obtained by photographing a calibration object with known world coordinates and using the PnP (Perspective-n-Point) algorithm to solve.

[0099] The pixel coordinate system is the position coordinate system of each pixel point in the image, usually with the upper left corner of the image as the origin, and the unit is pixel. The coordinates (u, v) of the feature points in the pixel coordinate system in the calibration board image can be obtained through the feature point detection algorithm.

[0100] Since the pixel coordinates are affected by the camera focal length, it is necessary to first convert them to the image plane coordinate system for standardization to eliminate the influence of the focal length. The image plane coordinate system is a standardized coordinate system used to represent the position of points in the image on the camera optical projection plane. Through this coordinate system, the influence of internal characteristics of the camera such as the focal length and the optical center in the pixel coordinates can be removed. The coordinates in the pixel coordinate system are converted into the image plane coordinate system coordinates through the following formula:

[0101]

[0102] where, xn and y n are the corresponding points of (u, v) in the image plane coordinate system respectively.

[0103] The camera coordinate system is a three-dimensional coordinate system with the camera as the origin, used to describe the position of the object observed by the camera in three-dimensional space. Since the images obtained by the binocular camera do not have depth information, therefore, in the process of converting the coordinates from the image plane coordinate system to the camera coordinate system, it is necessary to assume the depth Z to represent the distance from the feature point to the camera. The image plane coordinates can be converted to camera coordinates through the following formula:

[0104] X c = x n · Z

[0105] Y c = y n · Z

[0106] Z c = Z

[0107] Among them, (X c , Y c , Z c ) are the three-dimensional coordinates of the feature point in the camera coordinate system. Since the binocular camera can simultaneously capture the calibration board at different positions, the value of the depth Z can be determined by calculating the parallax. The depth Z is calculated through the following formula:

[0108]

[0109] Among them, f is the focal length of the camera, B is the baseline distance between the two cameras, and d is the parallax, that is, the horizontal displacement of the corresponding points of the feature point in the left and right images in the horizontal direction.

[0110] After obtaining the value of the depth Z through the above formula, the coordinates (X c , Y c , Z c ) of the feature point in the camera coordinate system can be determined. Furthermore, the position of the feature point in the world coordinate system can be obtained. The world coordinate system is the coordinate system that needs to be obtained finally, used to represent the position of the object in the real world of the three-dimensional world. The coordinates of the feature point in the world coordinate system can be obtained by solving the following formula:

[0111]

[0112] Among them, R 3×3 is the rotation matrix in the external parameter information, t 3×1 is the translation vector in the external parameter information, and (X w , Y w , Z w ) are the coordinates of the feature point in the world coordinate system.

[0113] In some alternative embodiments, determining the first pose information according to the world coordinate system coordinates of the feature points includes:

[0114] S10221. Obtain the world coordinate system coordinates of at least three feature points;

[0115] S10222. Calculate the six-degree-of-freedom pose of the calibration plate according to the world coordinate system coordinates of at least three feature points to obtain the first pose information.

[0116] Specifically, in this embodiment, after obtaining the coordinates of the feature points in the world coordinate system, the translation position information of the calibration plate is obtained by calculating the average value of the feature points. The cross product of the vectors of two feature points is selected to obtain the normal vector, and then a local coordinate system is constructed according to the normal vector and a feature point to determine the orientation of the calibration plate, form a rotation matrix, and calculate the Euler angle through the rotation matrix to determine the rotation position information of the calibration plate. Combining the translation position information and the rotation position information to obtain the complete six-degree-of-freedom pose information of the calibration plate.

[0117] In some alternative embodiments, determining the second pose information of the electric spindle according to the first pose information includes:

[0118] S1031. Obtain the relative pose relationship between the calibration plate and the electric spindle;

[0119] S1032. Transform the first pose information according to the relative pose relationship to obtain the second pose information.

[0120] In some alternative embodiments, the relative pose relationship includes the displacement relationship and the rotation relationship of the electric spindle relative to the calibration plate. Transforming the first pose information according to the relative pose relationship to obtain the second pose information includes:

[0121] S10321. Determine the displacement relationship and the rotation relationship according to the relative pose relationship;

[0122] S10322. Transform the first pose information according to the displacement relationship and the rotation relationship to obtain the second pose information.

[0123] Specifically, in this embodiment, since the calibration plate and the electric spindle are rigidly connected by a special fixture, the relationship between their spatial positions and orientations is fixed. The relative pose relationship between the two includes the relative displacement relationship and the relative rotation relationship. The rotation matrix and translation vector of the electric spindle relative to the calibration plate can be measured after installing the fixture, and the pose information of the electric spindle can be obtained by operating the known pose information of the calibration plate with the rotation matrix and translation vector.

[0124] Referring to Figure 3 , the embodiment of the present invention provides a casting grinding dynamic error compensation system, including:

[0125] A grinding module, configured to determine the ideal pose of the electric spindle, and control the electric spindle to grind the target casting according to the ideal pose by an industrial robot;

[0126] A pose determination module, configured to obtain the image information of the calibration plate, and position the calibration plate according to the image information to obtain the first pose information of the calibration plate;

[0127] A pose conversion module, configured to determine the second pose information of the electric spindle according to the first pose information;

[0128] An error compensation module, configured to determine the pose error of the electric spindle according to the second pose information and the ideal pose, and control the pose of the electric spindle by an industrial robot according to the pose error;

[0129] Wherein, the calibration plate is fixedly connected to the electric spindle.

[0130] Refer to Figure 4 , an embodiment of the present invention provides a computer device, including:

[0131] At least one processor;

[0132] At least one memory, configured to store at least one program;

[0133] When the above at least one program is executed by the above at least one processor, the above at least one processor implements the above-mentioned method for compensating dynamic errors in casting grinding.

[0134] The content in the above method embodiments is applicable to the system embodiments of the present invention. The functions specifically implemented by the system embodiments of the present invention are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0135] An embodiment of the present invention also provides a computer-readable storage medium, in which a program executable by a processor is stored, and the program executable by the processor is used to execute the above-mentioned method for compensating dynamic errors in casting grinding when executed by the processor.

[0136] A computer-readable storage medium according to an embodiment of the present invention can execute the method for compensating dynamic errors in casting grinding provided by the method embodiment of the present invention, can execute any combination of the implementation steps of the method embodiment, and has the corresponding functions and beneficial effects of the method.

[0137] An embodiment of the present invention also discloses a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of the computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes Figure 1 the dynamic error compensation method for casting grinding shown.

[0138] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order mentioned in the operation diagrams. For example, depending on the functions / operations involved, two consecutive blocks shown may actually be executed substantially simultaneously or the above-mentioned blocks can sometimes be executed in the reverse order. In addition, the embodiments presented and described in the flowcharts of the present invention are provided by way of example for the purpose of providing a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logical flows presented herein. Alternative embodiments are foreseeable, in which the order of various operations is changed and the sub-operations described as part of a larger operation are executed independently.

[0139] In addition, although the present invention has been described in the context of functional modules, it should be understood that unless otherwise stated to the contrary, one or more of the above functions and / or features may be integrated in a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It can also be understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present invention. More precisely, considering the attributes, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the modules will be understood within the ordinary skills of an engineer. Therefore, those skilled in the art can implement the present invention as set forth in the claims without undue experimentation. It can also be understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0140] If the above functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the above methods in various embodiments of the present invention. The foregoing storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs, etc., which can store program codes of various kinds.

[0141] The logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch instructions from the instruction execution system, apparatus, or device and execute the instructions), or used in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0142] More specific examples (non-exhaustive list) of computer-readable media include the following: electrical connection parts with one or more wirings (electronic devices), portable computer disk cartridges (magnetic devices), random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), optical fiber devices, and portable compact disc read-only memories (CDROMs). Additionally, the computer-readable medium can even be paper or other suitable media on which the above program can be printed, because the above program can be obtained electronically, for example, by optically scanning the paper or other media, then editing, interpreting, or processing it in other suitable ways when necessary, and then storing it in a computer memory.

[0143] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0144] In the above description of this specification, the description with reference to the terms "one embodiment / example", "another embodiment / example" or "certain embodiments / examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0145] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

[0146] The above is a specific description of the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Those skilled in the art can also make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for compensating dynamic errors in casting grinding, characterized in that: include: Determine the ideal posture of the electric spindle, and control the electric spindle to grind the target casting according to the ideal posture through the industrial robot; Acquire image information of the calibration plate, and position the calibration plate according to the image information to obtain the first position information of the calibration plate; Determine second posture information of the electric spindle according to the first posture information; Determining a posture error of the electric spindle according to the second posture information and the ideal posture, and controlling the posture of the electric spindle according to the posture error through an industrial robot; Wherein, the calibration plate is fixedly connected to the electric spindle.

2. A casting grinding dynamic error compensation method according to claim 1, characterized in that: The image information includes pixel coordinate system coordinates of feature points of the calibration plate image, and acquiring the image information of the calibration plate includes: Acquire the calibration plate image through a binocular camera; Detect the calibration plate image using a feature point detection algorithm to obtain pixel coordinates of the feature points; Wherein, the binocular camera is installed above the calibration plate.

3. A casting grinding dynamic error compensation method according to claim 2, characterized in that: Positioning the calibration plate according to the image information to obtain the first position information of the calibration plate includes: Determine the world coordinate system coordinates of the feature point according to the pixel coordinate system coordinates of the feature point; The first posture information is determined according to the world coordinate system coordinates of the feature point.

4. A casting grinding dynamic error compensation method according to claim 3, characterized in that: The determining the world coordinate system coordinates of the feature point according to the pixel coordinate system coordinates of the feature point comprises: Calibrate the binocular camera to obtain internal reference information and external reference information of the binocular camera; Determine the image plane coordinate system coordinates of the feature point according to the pixel coordinate system coordinates of the feature point and the intrinsic reference information; Determine the camera coordinate system coordinates of the feature point according to the image plane coordinate system coordinates of the feature point and the projection relationship of the binocular camera; The world coordinate system coordinates of the feature point are determined according to the camera coordinate system coordinates of the feature point and the external parameter information.

5. A casting grinding dynamic error compensation method according to claim 3, characterized in that: The determining the first posture information according to the world coordinate system coordinates of the feature point includes: Obtaining world coordinate system coordinates of at least three of the feature points; The six-degree-of-freedom posture of the calibration plate is calculated according to the world coordinate system coordinates of at least three of the feature points to obtain the first posture information.

6. A casting grinding dynamic error compensation method according to claim 1, characterized in that: Determining the second posture information of the electric spindle according to the first posture information includes: Obtaining the relative position and posture relationship between the calibration plate and the electric spindle; The first posture information is transformed according to the relative posture relationship to obtain the second posture information.

7. A casting grinding dynamic error compensation method according to claim 6, characterized in that: The relative posture relationship includes a displacement relationship and a rotation relationship of the electric spindle relative to the calibration plate, and the first posture information is transformed according to the relative posture relationship to obtain the second posture information, including: Determine the displacement relationship and the rotation relationship according to the relative posture relationship; The first posture information is transformed according to the displacement relationship and the rotation relationship to obtain the second posture information.

8. A casting grinding dynamic error compensation system, characterized in that: include: A grinding module is used to determine the ideal position and posture of the electric spindle, and to control the electric spindle to grind the target casting according to the ideal position and posture through an industrial robot; A posture determination module is used to obtain image information of the calibration plate, and locate the calibration plate according to the image information to obtain the first posture information of the calibration plate; A posture conversion module, used for determining second posture information of the electric spindle according to the first posture information; an error compensation module, used to determine a posture error of the electric spindle according to the second posture information and the ideal posture, and control the posture of the electric spindle according to the posture error through an industrial robot; Wherein, the calibration plate is fixedly connected to the electric spindle.

9. A device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements a casting grinding dynamic error compensation method as described in any one of claims 1-7.

10. A computer-readable storage medium storing a program executable by a processor, characterized in that: The program executable by the processor is used to execute a casting grinding dynamic error compensation method as described in any one of claims 1 to 7 when executed by the processor.

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