Workpiece pose calibration method, device and system, storage medium and program product

Abstract

The invention relates to a machined part pose calibration method, device and system, a storage medium and a program product. The method comprises the steps that the method is applied to a multi-axis motion system, the multi-axis motion system comprises a working part and a workbench, a monocular camera is arranged on the working part, and a first calibration plate is placed on the workbench; comprising the following steps: under the condition that a first calibration plate is imaged in a view field range of a monocular camera, selecting a coordinate reference point in a depth-of-field region in the view field range; under the condition that the workpiece feature points of the machined workpiece coincide with the coordinate reference points, coordinate pair information of the workpiece feature points is obtained; according to the current reference workpiece coordinate and the current reference mechanical coordinate, a target position motion relation and a target vector motion relation between the machined part and the multi-axis motion system are constructed respectively; and according to the target vector motion relation and the target position motion relation, pose calibration is conducted on the machined part. By adopting the method, the calibration limitation of the pose calibration of the machined part is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of multi-axis motion systems, and in particular to a method, device, system, computer-readable storage medium and computer program product for calibrating the position and posture of a workpiece. Background Art

[0002] With the continuous development of science and technology, there are increasingly higher requirements for the processing complexity, precision and process of workpieces. The requirements for spatial positioning accuracy in different application scenarios have been raised to the micron or even sub-micron level. In mechanical equipment that deploys multi-axis motion systems, in order to meet processing needs, high-precision posture calibration of the workpiece in three-dimensional space is indispensable.

[0003] At present, in the process of calibrating the posture of the workpiece of the multi-axis motion system, high-precision equipment is usually used. For example, the three-dimensional coordinate information of the workpiece is obtained by using a monocular camera and a ranging sensor in combination, or by using a surface structured light camera, a line structured light camera, and a binocular camera. However, the above-mentioned high-precision equipment may not be available in actual application scenarios. At the same time, different high-precision equipment has subjective defects when calibrating the posture of the workpiece, resulting in the final three-dimensional coordinate information being unable to match the user's actual posture calibration requirements, which makes it easy to have poor calibration accuracy. Therefore, the current calibration of the posture of the workpiece has high limitations. Summary of the invention

[0004] Based on this, it is necessary to provide a workpiece posture calibration method, device, system, computer-readable storage medium and computer program product that reduce the calibration limitations of workpiece posture calibration in order to address the above-mentioned technical problems.

[0005] In a first aspect, the present application provides a workpiece posture calibration method, which is applied to a multi-axis motion system, wherein the multi-axis motion system includes a working component and a workbench, wherein a monocular camera is provided on the working component, and a first calibration plate is placed on the workbench; the method includes:

[0006] When the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in a depth of field area within the field of view;

[0007] In the case where the workpiece feature point of the workpiece coincides with the coordinate reference point, obtaining coordinate pair information of the workpiece feature point, wherein the coordinate pair information includes a current reference mechanical coordinate of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and a current reference workpiece coordinate in the workpiece coordinate system of the workpiece;

[0008] According to the current reference workpiece coordinates and the current reference machine coordinates, a target position motion relationship and a target vector motion relationship are respectively constructed, wherein the target position motion relationship is the position motion relationship between the workpiece and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the workpiece and the multi-axis motion system;

[0009] The workpiece is calibrated in position and posture according to the target vector motion relationship and the target position motion relationship.

[0010] In one embodiment, constructing a target position motion relationship and a target vector motion relationship respectively according to the current reference workpiece coordinates and the current reference machine coordinates includes:

[0011] Acquire a position-motion relationship between the first calibration plate and the multi-axis motion system, wherein the position-motion relationship is used to characterize a position and posture of the first calibration plate relative to the multi-axis motion system;

[0012] Determining the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system according to the current reference mechanical coordinates and the position motion relationship;

[0013] Determining a position and posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates;

[0014] Constructing the target position motion relationship according to the position motion relationship and the posture relationship;

[0015] Constructing a vector motion relationship between the first calibration plate and the multi-axis motion system according to the current reference mechanical coordinates and the first external parameters of the monocular camera;

[0016] Determining a rotational relationship between the first calibration plate and the workpiece in the posture relationship;

[0017] The target vector motion relationship is constructed according to the vector motion relationship and the rotation relationship.

[0018] In one embodiment, a second calibration plate is further placed on the workbench, and the second calibration plate is parallel to the monocular camera and the workpiece, respectively; before determining the posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates, the method further includes:

[0019] Determining a pose conversion parameter of the workpiece feature point relative to the monocular camera according to a first parameter between the second calibration plate and the monocular camera and a second parameter of the second calibration plate;

[0020] According to the posture conversion parameters, the current reference workpiece coordinates of the coordinate reference point in the workpiece coordinate system are determined.

[0021] In one embodiment, determining the positional relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates includes:

[0022] Acquire a vector motion relationship between the first calibration plate and the multi-axis motion system; and construct a position motion relationship between the first calibration plate and the multi-axis motion system according to the current reference calibration coordinates, the current reference workpiece coordinates and the vector motion relationship.

[0023] In one embodiment, the step of obtaining the position motion relationship between the first calibration plate and the multi-axis motion system includes:

[0024] When the first calibration plate is imaged within the field of view of the monocular camera, locating the calibration mechanical coordinates of the multi-axis motion system in different positions and acquiring a first target calibration plate image of the first calibration plate;

[0025] Determining a second external parameter of the monocular camera relative to the first calibration plate according to the first calibration feature points in the plurality of first target calibration plate images;

[0026] Generate first initial coordinate pair information of the coordinate reference point according to the plurality of calibrated machine coordinates and the plurality of second external parameters, wherein the first initial coordinate pair information is composed of initial reference machine coordinates and initial reference calibrated coordinates;

[0027] Constructing a position kinematic chain model of the multi-axis motion system according to the initial reference mechanical coordinates and the initial reference calibration coordinates;

[0028] A position-kinematic relationship between the first calibration plate and the workpiece is constructed according to a position-kinematic chain model and a first model parameter of the position-kinematic chain model.

[0029] In one embodiment, the obtaining of the vector motion relationship between the first calibration plate and the multi-axis motion system includes:

[0030] When the first calibration plate is imaged within the field of view of the monocular camera, locating calibration motion vectors of the multi-axis motion system in different positions and acquiring a second target calibration plate image of the first calibration plate;

[0031] Determining a third external parameter of the monocular camera relative to the first calibration plate according to the second calibration feature points in the plurality of second target calibration plate images;

[0032] Generate second initial coordinate pair information of the coordinate reference point according to the plurality of calibration motion vectors and the plurality of third external parameters, wherein the second initial coordinate pair information is composed of an initial reference mechanical motion vector and an initial reference calibration motion vector;

[0033] Constructing a vector kinematic chain model of the multi-axis motion system according to the initial reference mechanical motion vector and the initial reference calibration motion vector;

[0034] A vector motion relationship between the first calibration plate and the multi-axis motion system is constructed according to a vector motion chain model and a second model parameter of the vector motion chain model.

[0035] In a second aspect, the present application further provides a workpiece posture calibration device, which is applied to a multi-axis motion system, wherein the multi-axis motion system includes a working component and a workbench, wherein a monocular camera is provided on the working component, and a first calibration plate is placed on the workbench; the device includes:

[0036] A selection module, used for selecting a coordinate reference point in a depth of field area within the field of view when the first calibration plate is imaged within the field of view of the monocular camera;

[0037] an acquisition module, configured to acquire coordinate pair information of the workpiece feature point when the workpiece feature point of the workpiece coincides with the coordinate reference point, wherein the coordinate pair information includes a current reference mechanical coordinate of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and a current reference workpiece coordinate in the workpiece coordinate system of the workpiece;

[0038] A construction module, used to construct a target position motion relationship and a target vector motion relationship respectively according to the current reference workpiece coordinates and the current reference machine coordinates, wherein the target position motion relationship is the position motion relationship between the workpiece and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the workpiece and the multi-axis motion system;

[0039] A calibration module is used to calibrate the position and posture of the workpiece according to the target vector motion relationship and the target position motion relationship.

[0040] In a third aspect, the present application also provides a workpiece position and posture calibration system, the system comprising:

[0041] A working component, wherein a monocular camera is disposed on the working component;

[0042] A workbench, on which a first calibration plate is placed;

[0043] A control device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0044] When the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in the depth of field area within the field of view; when a workpiece feature point of the processed part and the coordinate reference point coincide with each other, coordinate pair information of the workpiece feature point is obtained, wherein the coordinate pair information includes the current reference mechanical coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and the current reference workpiece coordinates in the workpiece coordinate system of the processed part; according to the current reference workpiece coordinates and the current reference mechanical coordinates, a target position motion relationship and a target vector motion relationship are respectively constructed, wherein the target position motion relationship is the position motion relationship between the processed part and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the processed part and the multi-axis motion system.

[0045] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the following steps are implemented:

[0046] When the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in the depth of field area within the field of view; when a workpiece feature point of the processed part and the coordinate reference point coincide with each other, coordinate pair information of the workpiece feature point is obtained, wherein the coordinate pair information includes the current reference mechanical coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and the current reference workpiece coordinates in the workpiece coordinate system of the processed part; according to the current reference workpiece coordinates and the current reference mechanical coordinates, a target position motion relationship and a target vector motion relationship are respectively constructed, wherein the target position motion relationship is the position motion relationship between the processed part and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the processed part and the multi-axis motion system.

[0047] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0048] When the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in the depth of field area within the field of view; when a workpiece feature point of the processed part and the coordinate reference point coincide with each other, coordinate pair information of the workpiece feature point is obtained, wherein the coordinate pair information includes the current reference mechanical coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and the current reference workpiece coordinates in the workpiece coordinate system of the processed part; according to the current reference workpiece coordinates and the current reference mechanical coordinates, a target position motion relationship and a target vector motion relationship are respectively constructed, wherein the target position motion relationship is the position motion relationship between the processed part and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the processed part and the multi-axis motion system.

[0049] The above-mentioned workpiece pose calibration method, device, system, computer-readable storage medium and computer program product first deploy a working component and a workbench in a multi-axis motion system, wherein a monocular camera is provided on the working component and a first calibration plate is placed on the workbench, and then when the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in the depth of field area within the field of view, so that a clear reference point can be selected for subsequent pose calibration, and then when the workpiece feature point of the workpiece and the coordinate reference point coincide with each other, the coordinate pair information of the coordinate reference point can be used as the coordinate pair information of the workpiece, that is, when the workpiece feature point of the workpiece and the coordinate feature point coincide with each other, the coordinate pair information of the workpiece feature point can be obtained, that is, the current reference mechanical coordinates and the current reference workpiece coordinates of the workpiece feature point are obtained, wherein the current reference mechanical coordinates are the current coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system, and the current reference workpiece coordinates are the current coordinates of the coordinate reference point in the workpiece coordinate system of the first calibration plate. Then, the target vector motion relationship between the workpiece and the multi-axis motion system can be respectively constructed by the current reference calibration coordinates and the current reference mechanical coordinates of the workpiece feature points. Finally, the workpiece is calibrated according to the target vector motion relationship and the target position motion relationship, so as to achieve the purpose of synchronously compensating the coordinate error and vector error of the multi-axis motion system. At the same time, since the multi-axis motion system only relies on a monocular camera to complete the pose calibration of the workpiece, and the monocular camera has advantages in cost and deployment environment compared to high-precision equipment, the subjective defects of the pose calibration equipment in calibrating the pose of the workpiece are avoided. Therefore, the problem that the above-mentioned high-precision equipment may not be provided in the actual application scenario is overcome. At the same time, different high-precision equipment has subjective defects in the pose calibration of the workpiece, resulting in the final three-dimensional coordinate information cannot match the user's actual pose calibration requirements, which makes it easy to have a technical defect of poor calibration accuracy. Therefore, the calibration limitations of the pose calibration of the workpiece are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 This is a schematic diagram of a process flow of a method for calibrating a workpiece posture in one embodiment of the present application;

[0052] Figure 2 A schematic diagram of coordinate reference points selected from a depth of field region within the field of view of a monocular camera in a method for calibrating a workpiece position and posture in one embodiment of the present application;

[0053] Figure 3 This is a schematic flow chart of a method for calibrating the position and posture of a workpiece in another embodiment of the present application;

[0054] Figure 4 This is a structural block diagram of a workpiece position and posture calibration device in one embodiment of the present application;

[0055] Figure 5 This is a diagram of the internal structure of a computer device in one embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0057] First of all, it should be understood that in the application scenarios of processing, dispensing, inspection, handling and grasping of multi-axis motion systems, it is necessary to calibrate the workpiece with high precision in three-dimensional space. At present, the equipment for obtaining three-dimensional information of workpieces includes: 1) monocular camera and ranging sensor; 2) surface structured light camera; 3) line structured light camera; 4) binocular camera. It can be understood that after the workpiece is calibrated, the three-dimensional information can be applied to multi-axis motion system calibration, workpiece teaching, three-dimensional reconstruction and measurement. However, when using the above equipment to calibrate the workpiece, there are subjective defects. For example, the three-dimensional information of the workpiece is obtained by using a monocular camera and a ranging sensor. In essence, the coordinates of the workpiece in the x-axis and y-axis directions are obtained by the monocular camera, and the coordinates of the workpiece in the z-axis direction are obtained by the ranging sensor. The monocular camera and the ranging sensor are different hardware devices, and the coordinate information of different dimensions obtained by them will exist. At the same time, before calibrating the workpiece's posture, the monocular camera and the ranging sensor need to be calibrated, which makes it difficult to ensure the accuracy of the final three-dimensional information of the workpiece; calibrating the three-dimensional information of the workpiece through the surface structured light camera and the line structured light camera will involve the calibration of the internal and external parameters of the camera itself, resulting in a certain accuracy error in the process of posture calibration, and it is expensive; and although the use of binocular cameras can ensure a high point sampling accuracy, its actual deployment process will have certain requirements on the spatial size of the processing machine tool. Therefore, the three-dimensional coordinate information obtained by the traditional method of calibrating the posture of the workpiece cannot match the actual posture calibration requirements of the user. More importantly, in the above-mentioned posture calibration process, only the coordinate error of the multi-axis motion system can be compensated, and the vector error compensation of the multi-axis motion system is not involved. Therefore, there is an urgent need for a workpiece posture calibration method that reduces the calibration limitations of the workpiece posture calibration.

[0058] In one embodiment, Figure 1As shown, a method for calibrating the position and posture of a workpiece is provided. This embodiment takes the method applied to a multi-axis motion system as an example, wherein the multi-axis motion system can be specifically a five-axis motion system or a six-axis motion system, etc. The multi-axis motion system includes a working component and a workbench, wherein a monocular camera is arranged on the working component, and a first calibration plate is placed on the workbench. The working component can be specifically an adjustable fixing component for fixing the monocular camera at different spatial positions. The multi-axis motion system also includes a control device. It can be understood that the control device is a control that coordinates and controls the hardware and software structure of the entire system around complex movements. Specifically, it can be a terminal device such as an embedded industrial computer, or a device such as a controller or a processor. The multi-axis motion system includes a selection module, an acquisition module, a construction module and a calibration module, wherein the selection module is used to select a coordinate reference point in a depth of field area within the field of view when the first calibration plate is imaged within the field of view of the monocular camera, and the acquisition module is used to obtain the coordinate pair of the workpiece feature point when the workpiece feature point and the coordinate reference point coincide with each other. Information, wherein the coordinate pair information is composed of the current reference mechanical coordinates and the current reference workpiece coordinates, the current reference mechanical coordinates are the current coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system, and the current reference workpiece coordinates are the current coordinates of the coordinate reference point in the workpiece coordinate system of the first calibration plate; the construction module is used to construct the target position motion relationship and the target vector motion relationship according to the current reference workpiece coordinates and the current reference mechanical coordinates, respectively; the calibration module is used to calibrate the workpiece according to the target vector motion relationship and the target position motion relationship, and through the information interaction between the selection module, the acquisition module, the construction module and the calibration module, the purpose of synchronously compensating the coordinate error and the vector error of the multi-axis motion system can be achieved. At the same time, since the multi-axis motion system only relies on a monocular camera to complete the pose calibration of the workpiece, and the monocular camera has advantages in cost and deployment environment compared to high-precision equipment, thereby avoiding the subjective defects of the pose calibration equipment when calibrating the pose of the workpiece, so it can reduce the calibration limitations of the pose calibration of the workpiece. In this embodiment, the method includes the following steps:

[0059] Step 202 , when the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in the depth of field area within the field of view.

[0060] It should be noted that "calibration" refers to the process of establishing a correspondence between the mechanical coordinate system of the multi-axis motion system itself and the standard space coordinate system, so as to convert them into each other to obtain several sets of corresponding coordinate data. A monocular camera is arranged on the working part, and the monocular camera can take pictures within the field of view. By adjusting the working part, the monocular camera can take pictures within the field of view at different positions and angles. The first calibration plate is arranged on the workbench, and the calibration feature points on the first calibration plate carry known coordinate information in the standard space coordinate system. It can be understood that the coordinates of the space point in the calibration coordinate system can be understood as the coordinates of the space point in the standard space coordinate system.

[0061] In an implementable manner, the equipment environment for performing workpiece posture calibration can be mainly composed of a five-axis motion platform, a monocular camera, a light source and a first calibration plate, wherein the field of view size and camera accuracy of the monocular camera can be obtained by adjusting the parameters of the monocular camera, and the type, material and size of the first calibration plate are not specifically limited in this embodiment. For example, the type of the first calibration plate can specifically include but are not limited to a chessboard and a circular grid, etc., the material of the first calibration plate can specifically include but are not limited to ceramic, glass, quartz or metal, etc., the size of the first calibration plate can be set by the operator as needed, the type of light source can be adapted to the requirements of the application scenario, and can specifically be a coaxial light source, a ring light source or a backlight source, etc. Specifically, the field of view size of the monocular camera can be set to 30*30, the camera accuracy can be set to 1.5 silk, the first calibration plate can be a chessboard calibration plate, and the light source can be selected as a backlight source, so as to build an equipment environment for performing the workpiece posture calibration method.

[0062] It should be noted that by controlling the working part to adjust its position through the control device, the first calibration plate can be imaged within the field of view of the monocular camera. It can be understood that the field of view of the monocular camera refers to the scene range that the monocular camera can capture, and the depth of field area within the field of view refers to the distance range of objects that can be clearly imaged within the field of view of the camera. It can be understood that after selecting any feature point in the scene in the depth of field area, the feature point can be clearly imaged. If the monocular camera has been calibrated, the conversion relationship between the feature point and the corresponding point in the calibration coordinate system of the first calibration plate can be used to obtain the coordinate pair information of the feature point, wherein the coordinate pair information of the feature point includes the coordinates in the mechanical coordinate system of the multi-axis motion system and the coordinates in the calibration coordinate system of the first calibration plate, that is, the coordinate conversion relationship between different coordinate systems can be established through the feature point. Therefore, the coordinate reference point is used to characterize the feature point carrying coordinate information in different coordinate systems. Figure 2 , Figure 2 The figure is a schematic diagram of a coordinate reference point selected in a depth of field region within the field of view of a monocular camera, wherein the coordinate reference point may be located on the optical axis of the monocular camera. It is understandable that the selected coordinate reference point may not be located on the optical axis.

[0063] As an example, step 202 includes: after fixing the first calibration plate on the workbench, controlling the working component to adjust the shooting position of the monocular camera so that the first calibration plate is imaged within the field of view of the monocular camera, and when it is detected that the first calibration plate is imaged within the field of view of the monocular camera, randomly selecting a coordinate feature point in the depth of field area within the field of view as a coordinate reference point.

[0064] In one feasible manner, detecting whether the first calibration plate is imaged within the field of view of the monocular camera can be determined based on identifying the first target calibration plate image captured at a specified shooting position. It can be understood that when the complete edge features of the first calibration plate are identified in the first target calibration plate image, it is determined that the first calibration plate captured at the specified shooting position can be imaged within the field of view of the monocular camera.

[0065] Step 204, when the workpiece feature point and the coordinate reference point of the processed part coincide with each other, obtain the coordinate pair information of the workpiece feature point, wherein the coordinate pair information is composed of the current reference machine coordinates and the current reference workpiece coordinates, the current reference machine coordinates are the current coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system, and the current reference workpiece coordinates are the current coordinates of the coordinate reference point in the workpiece coordinate system of the first calibration plate.

[0066] It should be noted that a point is randomly selected in the workpiece as a workpiece feature point, and the control device controls the workpiece to be located at the coordinate reference point, so that the workpiece feature point can use the coordinate pair information of the coordinate reference point as its own coordinate pair information, wherein the coordinate pair information can be specifically composed of the current reference mechanical coordinates and the current reference calibration coordinates, the current reference mechanical coordinates are the current coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system, and the current reference workpiece coordinates are the current coordinates of the coordinate reference point in the workpiece coordinate system of the first calibration plate.

[0067] As an example, step 204 includes: selecting a workpiece feature point on the workpiece, and controlling the workpiece feature point and the coordinate reference point to coincide with each other through a control device. When it is detected that the workpiece feature point and the coordinate reference point of the workpiece coincide with each other, the coordinate pair information of the coordinate reference point is used as the coordinate pair information of the workpiece feature.

[0068] Step 206 , constructing a target position motion relationship and a target vector motion relationship respectively according to the current reference workpiece coordinates and the current reference machine coordinates.

[0069] It should be noted that the target position motion relationship between the workpiece and the multi-axis motion system can be constructed through the current reference workpiece coordinates, that is, the relationship between the workpiece and the workpiece coordinate system is determined, and the target position motion relationship is used to characterize the position and posture of the workpiece relative to the multi-axis motion system. In addition, since the current reference mechanical coordinates are the coordinates of the workpiece feature points in the mechanical coordinate system, the moving direction and distance of the workpiece in the multi-axis motion system can be reflected through the current reference mechanical coordinates, that is, the target vector motion relationship between the workpiece and the multi-axis motion system can be constructed, wherein the target vector motion relationship is used to characterize the vector motion of the workpiece relative to the multi-axis motion system.

[0070] As an example, step 206 includes: obtaining a target position motion relationship between the workpiece and the multi-axis motion system by performing coordinate transformation on the current reference workpiece coordinates and the current reference machine coordinates, and obtaining a target vector motion relationship between the workpiece and the multi-axis motion system by performing coordinate transformation on the current reference workpiece coordinates and the current reference machine coordinates.

[0071] Step 208, calibrating the position and posture of the workpiece according to the target vector motion relationship and the target position motion relationship.

[0072] As an example, step 208 includes: calibrating the workpiece's posture according to the target vector motion relationship and the target position motion relationship, wherein the calibrated posture may specifically be the position coordinate values ​​of the five axes XYZBC and the motion vector value of the BC axis.

[0073] In the above-mentioned workpiece pose calibration method, firstly, a working component and a workbench are deployed in a multi-axis motion system, wherein a monocular camera is arranged on the working component, and a first calibration plate is placed on the workbench, and then when the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in the depth of field area within the field of view, so that a clear reference point can be selected for subsequent pose calibration, and then when the workpiece feature point of the workpiece and the coordinate reference point coincide with each other, the coordinate pair information of the coordinate reference point can be used as the coordinate pair information of the workpiece, that is, when the workpiece feature point of the workpiece and the coordinate feature point coincide with each other, the coordinate pair information of the workpiece feature point can be obtained, that is, the current reference mechanical coordinates and the current reference workpiece coordinates of the workpiece feature point are obtained, wherein the current reference mechanical coordinates are the current coordinates of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system, and the current reference workpiece coordinates are the current coordinates of the coordinate reference point in the workpiece coordinate system of the first calibration plate, and then the current reference mechanical coordinates of the workpiece feature point are obtained. By referring to the calibration coordinates and the current reference mechanical coordinates, the target vector motion relationship between the workpiece and the multi-axis motion system can be respectively constructed. Finally, according to the target vector motion relationship and the target position motion relationship, the workpiece is calibrated to achieve the purpose of synchronously compensating the coordinate error and vector error of the multi-axis motion system. At the same time, since the multi-axis motion system only relies on a monocular camera to complete the pose calibration of the workpiece, and the monocular camera has advantages in cost and deployment environment compared to high-precision equipment, the subjective defects of the pose calibration equipment in calibrating the pose of the workpiece are avoided. Therefore, the problem that the above-mentioned high-precision equipment may not be provided in the actual application scenario is overcome. At the same time, different high-precision equipment has subjective defects when calibrating the pose of the workpiece, resulting in the final three-dimensional coordinate information cannot match the user's actual pose calibration requirements, which makes it easy to have a technical defect of poor calibration accuracy. Therefore, the calibration limitations of the workpiece pose calibration are reduced.

[0074] In one embodiment, Figure 3 As shown, the target position motion relationship and the target vector motion relationship are constructed according to the current reference workpiece coordinates and the current reference machine coordinates, respectively, including:

[0075] Step 302: Acquire a position-motion relationship between the first calibration plate and the multi-axis motion system, wherein the position-motion relationship is used to characterize a position and posture of the first calibration plate relative to the multi-axis motion system.

[0076] It should be noted that before calibrating the position and posture of the workpiece, the position and motion relationship between the first calibration plate and the multi-axis motion system can be calibrated based on the monocular camera and the first calibration plate, that is, the coordinate calibration process of the multi-axis motion system is completed.

[0077] As an example, step 302 includes: establishing a position-motion relationship between the first calibration plate and the multi-axis motion system.

[0078] Step 304 , determining the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system according to the current reference mechanical coordinates and the position motion relationship.

[0079] It should be noted that since the position-motion relationship is used to characterize the posture of the first calibration plate relative to the multi-axis motion system, and the current reference mechanical coordinates of the workpiece feature point in the mechanical coordinate system are known, the coordinate representation of the coordinate reference point in the calibration coordinate system can be obtained from the known current reference mechanical coordinates and the position-motion relationship between the first calibration plate and the multi-axis motion system, that is, the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system can be obtained.

[0080] As an example, step 304 includes: according to the position-motion relationship, converting the current reference mechanical coordinates into the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system.

[0081] Step 306: Determine the position and posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates.

[0082] It should be noted that the current reference calibration coordinates refer to the coordinate representation of the coordinate reference point in the calibration coordinate system, and the current reference workpiece coordinates refer to the coordinate representation of the coordinate reference point in the workpiece coordinate system. Through the current reference calibration coordinates and the current reference workpiece coordinates, the position and posture relationship between the first calibration plate and the workpiece can be established through the coordinate reference point as the intermediary.

[0083] As an example, step 306 includes: constructing a posture relationship between the first calibration plate and the workpiece according to a coordinate correspondence relationship between the current reference calibration coordinates and the current reference workpiece coordinates.

[0084] Step 308: construct a target position motion relationship based on the position motion relationship and the posture relationship.

[0085] It should be noted that the position-motion relationship reflects the position-motion relationship between the first calibration plate and the multi-axis motion system, and the posture relationship reflects the posture relationship between the first calibration plate and the multi-axis motion system. Furthermore, through the position-motion relationship and the posture relationship, the target position-motion relationship between the workpiece and the multi-axis motion system can be determined through the first calibration plate as an intermediary.

[0086] As an example, step 308 includes: constructing a target position motion relationship according to the position motion relationship and the posture relationship.

[0087] Step 310: construct a vector motion relationship between the first calibration plate and the multi-axis motion system according to the current reference mechanical coordinates and the first external parameters of the monocular camera.

[0088] It should be noted that after obtaining the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system, the vector part of the current reference calibration coordinates is extracted to construct the vector motion relationship between the first calibration plate and the multi-axis motion system.

[0089] As an example, step 310 includes: constructing a vector motion relationship between the first calibration plate and the multi-axis motion system through the current reference calibration coordinates and the first external parameters of the monocular camera.

[0090] Step 312: determine the rotation relationship between the first calibration plate and the workpiece in the posture relationship.

[0091] As an example, a rotation matrix is ​​extracted from a posture matrix of the posture relationship, and a rotation relationship between the first calibration plate and the workpiece is established according to the rotation matrix.

[0092] Step 314: construct a target vector motion relationship according to the vector motion relationship and the rotation relationship.

[0093] It should be noted that the vector motion relationship reflects the vector motion relationship between the first calibration plate and the multi-axis motion system, and the rotation relationship reflects the rotation relationship between the first calibration plate and the workpiece. Furthermore, with the first calibration plate as an intermediary, the target vector motion relationship between the workpiece and the multi-axis motion system can be constructed based on the vector motion relationship and the rotation relationship.

[0094] As an example, step 314 includes: constructing a target vector motion relationship according to the vector motion relationship and the rotation relationship.

[0095] In this embodiment, when the coordinate reference point and the workpiece feature point coincide with each other, the coordinate pair information of the workpiece feature point can be reflected by the coordinate pair information of the coordinate reference point, and then based on the coordinate pair information, under the calibration capability of the first calibration plate, the position motion relationship between the first calibration plate and the multi-axis motion system, the posture relationship between the first calibration plate and the workpiece, the vector motion relationship between the first calibration plate and the multi-axis motion system, and the rotation relationship between the first calibration plate and the workpiece are established. This can achieve the purpose of constructing the target position motion relationship and the target vector motion relationship between the workpiece and the multi-axis motion system with the first calibration plate as the intermediary, thereby laying the foundation for reducing the calibration limitations of the workpiece posture calibration.

[0096] In one embodiment, a second calibration plate is also placed on the workbench, and the second calibration plate is parallel to the monocular camera and the workpiece respectively; before determining the posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates, the method further includes:

[0097] According to the first parameters between the second calibration plate and the monocular camera and the second parameters of the second calibration plate, the pose conversion parameters of the workpiece feature point relative to the monocular camera are determined; according to the pose conversion parameters, the current reference workpiece coordinates of the coordinate reference point in the workpiece coordinate system are determined.

[0098] It should be noted that, in order to improve the calibration accuracy, a second calibration plate can also be set on the workbench, the second calibration plate is parallel to the workpiece, and the second calibration plate is also parallel to the monocular camera. Specifically, the second calibration plate can be placed flat on the surface of the workpiece. Since the first parameter between the second calibration plate and the monocular camera and the second parameter of the second calibration plate are both known, the pose conversion parameters of the workpiece feature point relative to the monocular camera can be determined by the first parameter and the second parameter, wherein the first parameter can specifically be the height between the second calibration plate and the monocular camera, and the second parameter can specifically be the thickness of the second calibration plate, so that the pose conversion parameters determined by the two can be converted to obtain the current reference workpiece coordinates of the coordinate reference point in the workpiece coordinate system. It can be understood that the pose conversion parameters refer to the parameters for performing pose conversion from the coordinate reference point to the workpiece coordinate system. By introducing the pose conversion parameters, the current reference workpiece coordinates after the coordinate reference point is completely converted can be completely obtained, so that the pose relationship between the first calibration plate and the workpiece can be constructed using the current reference workpiece coordinates after the complete conversion, wherein the pose conversion parameters can be expressed in coordinate form.

[0099] As an example, the first parameters between the second calibration plate and the monocular camera and the second parameters of the second calibration plate are jointly converted into pose transformation parameters of the workpiece feature point relative to the monocular camera; based on the pose transformation parameters, the current reference workpiece coordinates of the coordinate reference point in the workpiece coordinate system are obtained.

[0100] In this embodiment, by additionally providing a second calibration plate in the multi-axis motion system and using the relevant parameters of the first calibration plate and the second calibration plate to obtain the current reference calibration coordinates, the purpose of using the current reference calibration coordinates to provide a basis for determining the posture relationship between the workpiece and the first calibration plate can be achieved. Therefore, while laying the foundation for reducing the calibration limitations of the workpiece posture calibration, the calibration accuracy of the workpiece posture calibration is improved.

[0101] In one embodiment, determining the position and posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates includes:

[0102] The vector motion relationship between the first calibration plate and the multi-axis motion system is obtained; and the position motion relationship between the first calibration plate and the multi-axis motion system is constructed according to the current reference calibration coordinates, the current reference workpiece coordinates and the vector motion relationship.

[0103] It should be noted that in the process of establishing the position-motion relationship between the first calibration plate and the multi-axis motion system, different posture transformation relationships can be used for construction. For example, in one feasible method, based on the pre-established position-motion relationship between the first calibration plate and the workpiece, the coordinate transformation of the current reference calibration coordinates can be performed with the workpiece as the intermediary, so as to directly construct the position-motion relationship by using multiple feature points obtained by transformation. Alternatively, based on the pre-established vector motion relationship between the first calibration plate and the multi-axis motion system, and the current reference calibration coordinates, the position-motion relationship can be constructed by using the vector position of the coordinate reference point relative to the multi-axis motion system under the current reference calibration coordinates.

[0104] As an example, a vector motion relationship between the first calibration plate and the multi-axis motion system is obtained; and a position motion relationship between the first calibration plate and the multi-axis motion system is constructed according to the current reference calibration coordinates, the current reference workpiece coordinates and the vector motion relationship.

[0105] In this embodiment, when establishing the position-motion relationship between the first calibration plate and the multi-axis motion system, the position-motion relationship can be constructed based on the vector motion relationship between the first calibration plate and the multi-axis motion system, the current reference workpiece coordinates and the current reference calibration coordinates, thereby avoiding the limitations in establishing the position-motion relationship between the first calibration plate and the multi-axis motion system, making the establishment of the position-motion relationship more flexible, and thus further reducing the calibration limitations of the workpiece posture calibration.

[0106] In one embodiment, obtaining the position motion relationship between the first calibration plate and the multi-axis motion system includes:

[0107] When the first calibration plate is imaged within the field of view of the monocular camera, the calibration mechanical coordinates of the multi-axis motion system in different postures and the first target calibration plate image of the first calibration plate are located; according to the first calibration feature points in the multiple first target calibration plate images, the second external parameters of the monocular camera relative to the first calibration plate are determined; according to the multiple calibration mechanical coordinates and the multiple second external parameters, the first initial coordinate pair information of the coordinate reference point is generated, wherein the first initial coordinate pair information is jointly constituted by the initial reference mechanical coordinates and the initial reference calibration coordinates; according to the initial reference mechanical coordinates and the initial reference calibration coordinates, a position motion chain model of the multi-axis motion system is constructed; according to the position motion chain model and the first model parameters of the position motion chain model, the position motion relationship between the first calibration plate and the workpiece is constructed.

[0108] It should be noted that the calibrated mechanical coordinates are the coordinates of the multi-axis motion system in the mechanical coordinate system at different postures, which can be specifically the machine tool posture value. The control device can control the multi-axis motion system to be in different postures. The first calibration feature point is the feature point on the first calibration plate, which can be specifically a corner point, a circle point or other mark point. The first external parameter refers to the external parameter corresponding to the monocular camera at each posture. The position motion chain model may be different based on the multi-axis motion system. It can be understood that through the constructed position motion chain model and the solved parameters, the kinematic relationship between the machine tool posture value and the calibration plate can be established, that is, the position motion relationship between the first calibration plate and the multi-axis motion system is established, and the forward and inverse solutions can be performed based on the position motion relationship.

[0109] As an example, when the first calibration plate is imaged within the field of view of the monocular camera, multiple postures of the multi-axis motion system are located, and the calibration mechanical coordinates of the multi-axis motion system in different postures and multiple first target calibration plate images of the first calibration plate are recorded; based on multiple corner points in the first target calibration plate image and the corresponding physical coordinates, the second external parameters of the monocular camera in different postures of the multi-axis motion system are calculated; based on the multiple calibration mechanical coordinates and the multiple second external parameters, the first initial coordinate pair information of the coordinate reference point is generated; based on the initial reference mechanical coordinates and the initial reference calibration coordinates, a position motion chain model of the multi-axis motion system is constructed; based on the position motion chain model and the first model parameters of the position motion chain model, the position motion relationship between the first calibration plate and the workpiece is constructed.

[0110] In an implementable manner, the coordinate calibration process of a five-axis motion platform based on a monocular camera is as follows: 1) Position the five-axis machine tool (this platform uses the XYZBC five-axis) in a posture so that the first calibration plate is imaged within the camera's field of view, record the current machine tool posture (XYZBC five-axis) value, and save the current image (first target calibration plate image); 2) Based on the first step, position the five-axis machine tool in multiple postures so that the first calibration plate is imaged within the camera's field of view, record the posture values ​​of each machine tool, and save images at each posture; 3) Identify the pixel coordinates corresponding to the first calibration feature point through the saved multiple images, and then calculate the external parameters corresponding to each posture of the camera internal participation (the posture relationship between the camera and the calibration plate) based on the corresponding physical coordinates; 4) Take a point within the camera's depth of field (the point does not necessarily need to be on the optical axis), select a set of data (including the machine tool posture value and the external parameters of the corresponding image), and calculate the point in the first The coordinates on the calibration plate form a new set of data (machine tool posture value and calibration plate coordinates), that is, generate the first initial coordinate pair information; 5) According to the fourth step, generate multiple sets of first initial coordinate pair information, each set of data consists of machine tool posture value and calibration plate coordinates; 6) According to the multiple sets of first initial coordinate pair information, based on the five-axis position coordinate motion chain model, construct a five-axis position coordinate motion chain model, and solve the model parameters; 7) According to the constructed motion chain model and the solved parameters, establish the kinematic relationship between the machine tool posture value and the calibration plate, that is, establish the position-motion relationship between the first calibration plate and the workpiece, and the forward and inverse solutions can be obtained based on the position-motion relationship; in addition, if it is necessary to establish the position-kinematic relationship between the machine tool and the workpiece, it is necessary to establish the posture relationship (rotation and translation matrix) between the calibration plate and the workpiece, so as to obtain the position-kinematic relationship between the machine tool and the workpiece, that is, to obtain the target position-motion relationship between the multi-axis motion system and the machining platform.

[0111] This embodiment only requires one camera without the aid of additional measuring equipment. Based on the multi-axis motion platform posture coordinate data and the camera calibration internal and external parameters, the position coordinate error can be effectively compensated. Therefore, it lays the foundation for reducing the calibration limitations of workpiece posture calibration.

[0112] In one embodiment, obtaining a vector motion relationship between the first calibration plate and the multi-axis motion system includes:

[0113] When the first calibration plate is imaged within the field of view of the monocular camera, the calibration motion vectors of the multi-axis motion system in different positions are located, and the second target calibration plate image of the first calibration plate is obtained; according to the second calibration feature points in the plurality of second target calibration plate images, the third external parameters of the monocular camera relative to the first calibration plate are determined; according to the plurality of calibration motion vectors and the plurality of third external parameters, second initial coordinate pair information of the coordinate reference point is generated, wherein the second initial coordinate pair information is jointly constituted by an initial reference mechanical motion vector and an initial reference calibration motion vector; according to the initial reference mechanical motion vector and the initial reference calibration motion vector, a vector motion chain model of the multi-axis motion system is constructed; according to the vector motion chain model and the second model parameters of the vector motion chain model, a vector motion relationship between the first calibration plate and the multi-axis motion system is constructed.

[0114] It should be noted that the vector motion relationship calibration process based on a monocular camera is similar to the position motion relationship calibration process, and this embodiment will not be repeated here.

[0115] In an implementable manner, the vector calibration process of a five-axis motion platform based on a monocular camera is as follows: 1) Position the five-axis machine tool (this platform uses the five-axis XYZBC) in a posture so that the first calibration plate is imaged within the camera's field of view, record the current machine tool posture (BC two-axis) value, and save the current image (first target calibration plate image); 2) Based on the first step, position the five-axis machine tool in multiple postures so that the first calibration plate is imaged within the camera's field of view, record the posture values ​​of each machine tool, and save images at each posture; 3) Identify the pixel coordinates corresponding to the first calibration feature point through the saved multiple images, and then calculate the external parameters corresponding to each posture in the camera (the posture relationship between the camera and the calibration plate) based on the corresponding physical coordinates; 4) Take a point within the camera's depth of field (the point does not necessarily need to be on the optical axis), select a set of data (including the machine tool posture value and the corresponding 5) According to the multiple sets of second initial coordinate pair information, based on the five-axis vector motion chain model, a five-axis vector motion chain model is constructed to solve the second model parameters; 6) According to the vector motion chain model constructed in step 5 and the solved second model parameters, the vector kinematic relationship between the machine tool attitude value and the calibration plate is established, and the forward and inverse solutions can be performed based on the vector kinematic relationship; in addition, if it is necessary to establish the vector kinematic relationship between the machine tool and the workpiece, it is necessary to establish the attitude relationship (rotation matrix) between the calibration plate and the workpiece, so as to obtain the vector kinematic relationship between the machine tool and the workpiece, that is, to obtain the target vector motion relationship between the workpiece and the multi-axis motion system.

[0116] This embodiment only requires one camera without the aid of additional measuring equipment. It can effectively compensate for the attitude vector error based on the attitude data of the multi-axis motion platform and the internal and external parameters of the camera calibration, thus laying the foundation for reducing the calibration limitations of the workpiece posture calibration.

[0117] In an implementable manner, the process of calibrating the posture of a workpiece using a five-axis motion platform based on a monocular camera is as follows: 1) A second calibration plate is placed on the plane of the workpiece, and the monocular camera shoots the second calibration plate to calculate the third external parameter; 2) Based on the above vector calibration process, the posture relationship between the current machine tool posture value and the first calibration plate can be calculated, that is, the vector motion relationship between the first calibration plate and the multi-axis motion system is obtained. According to the calculated external parameters in the first step, the second vector motion relationship between the second calibration plate and the multi-axis motion system can be established. Since the second calibration plate and the workpiece are parallel, the vector motion relationship between the multi-axis motion system and the workpiece is obtained; 3) Based on the above vector kinematic relationship, the BC axis value is calculated to make the second calibration plate parallel to the camera, thereby ensuring the high consistency from the camera to the workpiece plane; 4) Based on the third step and the workpiece 3D model drawing, add The thickness of the upper calibration plate can be used to calculate the height value from the current camera to any point on the workpiece; 5) Based on the fourth step of the coordinate calibration process of the five-axis motion platform, the height value h of a point in the depth of field is obtained, and the height from the camera to the feature point of the workpiece is set to h. Through image recognition, the feature point of the workpiece is imaged at the center of the field of view; 6) Based on the position kinematic relationship obtained by the above process and the coordinate calibration process, the coordinates of the feature point of the workpiece under the first calibration plate can be calculated, and the coordinates of the feature point of the workpiece in the workpiece coordinate system can be recorded. Based on step 2, the position and posture relationship between the first calibration plate and the workpiece can be obtained; 7) The position and kinematic relationship between the machine tool and the workpiece can be obtained, that is, the target position motion relationship between the multi-axis motion system and the workpiece is obtained; 8) At this point, the target position motion relationship and the target vector motion relationship have been obtained, and the position and posture calibration of the workpiece can be realized by relying on the target position motion relationship and the target vector motion relationship.

[0118] The above-mentioned workpiece pose calibration method can achieve the purpose of synchronously compensating the coordinate error and vector error of the multi-axis motion system. At the same time, since the multi-axis motion system only relies on a monocular camera to complete the pose calibration of the workpiece, and the monocular camera has advantages in cost and deployment environment compared to high-precision equipment, it avoids the subjective defects of the pose calibration equipment when calibrating the pose of the workpiece. Therefore, it overcomes the problem that the above-mentioned high-precision equipment may not be available in the actual application scenario. At the same time, different high-precision equipment has subjective defects when calibrating the pose of the workpiece, resulting in the final three-dimensional coordinate information cannot match the user's actual pose calibration requirements, which makes it easy to have a technical defect of poor calibration accuracy. Therefore, the calibration limitations of the workpiece pose calibration are reduced.

[0119] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0120] Based on the same inventive concept, the embodiment of the present application also provides a workpiece posture calibration device for implementing the workpiece posture calibration method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the workpiece posture calibration device provided below can refer to the limitations of the workpiece posture calibration method above, and will not be repeated here.

[0121] In an exemplary embodiment, Figure 4 As shown, it is applied to a multi-axis motion system, the multi-axis motion system includes a working component and a workbench, wherein the working component is provided with a monocular camera, and a first calibration plate is placed on the workbench; the device includes: a selection module 401, an acquisition module 402, a construction module 403 and a calibration module 404, wherein:

[0122] A selection module 401 is used to select a coordinate reference point in a depth of field area within the field of view when the first calibration plate is imaged within the field of view of the monocular camera;

[0123] An acquisition module 402 is used to acquire coordinate pair information of the workpiece feature point when the workpiece feature point of the workpiece coincides with the coordinate reference point, wherein the coordinate pair information includes a current reference mechanical coordinate of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and a current reference workpiece coordinate in the workpiece coordinate system of the workpiece;

[0124] A construction module 403 is used to construct a target position motion relationship and a target vector motion relationship respectively according to the current reference workpiece coordinates and the current reference machine coordinates, wherein the target position motion relationship is the position motion relationship between the workpiece and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the workpiece and the multi-axis motion system;

[0125] The calibration module 404 is used to calibrate the position and posture of the workpiece according to the target vector motion relationship and the target position motion relationship.

[0126] In one embodiment, the construction module 403 is further used to:

[0127] Obtain a position-motion relationship between the first calibration plate and the multi-axis motion system, wherein the position-motion relationship is used to characterize the posture of the first calibration plate relative to the multi-axis motion system; determine the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system according to the current reference calibration coordinates and the current reference workpiece coordinates; determine the posture relationship between the first calibration plate and the workpiece according to the position-motion relationship and the posture relationship; construct the target position-motion relationship according to the position-motion relationship and the posture relationship; construct the vector motion relationship between the first calibration plate and the multi-axis motion system according to the current reference mechanical coordinates and the first external parameters of the monocular camera; determine the rotation relationship between the first calibration plate and the workpiece in the posture relationship; and construct the target vector motion relationship according to the vector motion relationship and the rotation relationship.

[0128] In one embodiment, a second calibration plate is also placed on the workbench, and the second calibration plate is parallel to the monocular camera and the workpiece respectively; the workpiece position calibration device is also used for:

[0129] According to the first parameters between the second calibration plate and the monocular camera and the second parameters of the second calibration plate, the pose conversion parameters of the workpiece feature point relative to the monocular camera are determined; according to the pose conversion parameters, the current reference workpiece coordinates of the coordinate reference point in the workpiece coordinate system are determined.

[0130] In one embodiment, the construction module 403 is further used to:

[0131] Acquire a vector motion relationship between the first calibration plate and the multi-axis motion system; and construct a position motion relationship between the first calibration plate and the multi-axis motion system according to the current reference calibration coordinates, the current reference workpiece coordinates and the vector motion relationship.

[0132] In one embodiment, the device is further used for:

[0133] When the first calibration plate is imaged within the field of view of the monocular camera, the calibration mechanical coordinates of the multi-axis motion system in different positions are located, and the first target calibration plate image of the first calibration plate is obtained; according to the first calibration feature points in the multiple first target calibration plate images, the second external parameters of the monocular camera relative to the first calibration plate are determined; according to the multiple calibration mechanical coordinates and the multiple second external parameters, the first initial coordinate pair information of the coordinate reference point is generated, wherein the first initial coordinate pair information is jointly composed of the initial reference mechanical coordinates and the initial reference calibration coordinates; according to the initial reference mechanical coordinates and the initial reference calibration coordinates, a position motion chain model of the multi-axis motion system is constructed; according to the position motion chain model and the first model parameters of the position motion chain model, a position motion relationship between the first calibration plate and the workpiece is constructed.

[0134] In one embodiment, the construction module 403 is further used to:

[0135] When the first calibration plate is imaged within the field of view of the monocular camera, the calibration motion vectors of the multi-axis motion system in different positions are located, and a second target calibration plate image of the first calibration plate is obtained; according to the second calibration feature points in the second target calibration plate images, the third external parameters of the monocular camera relative to the first calibration plate are determined; according to the multiple calibration motion vectors and the multiple third external parameters, the second initial coordinate pair information of the coordinate reference point is generated, wherein the second initial coordinate pair information is jointly composed of an initial reference mechanical motion vector and an initial reference calibration motion vector; according to the initial reference mechanical motion vector and the initial reference calibration motion vector, a vector motion chain model of the multi-axis motion system is constructed; according to the vector motion chain model and the second model parameters of the vector motion chain model, a vector motion relationship between the first calibration plate and the multi-axis motion system is constructed.

[0136] Each module in the above-mentioned workpiece position and posture calibration device can be implemented in whole or in part by software, hardware and their combination. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0137] In an exemplary embodiment, a workpiece position and posture calibration system is provided, the system comprising:

[0138] A working part, on which a monocular camera is arranged; a workbench, on which a first calibration plate is placed; a control device; the control device may be a terminal, and its internal structure diagram may be as follows Figure 5As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface, the display unit and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, it implements a method for calibrating the position and posture of a workpiece. Those skilled in the art can understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0139] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0140] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0141] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0142] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for calibrating the position and posture of a workpiece, characterized in that: Applied to a multi-axis motion system, the multi-axis motion system includes a working component and a workbench, wherein the working component is provided with a monocular camera, and a first calibration plate is placed on the workbench; the method includes: When the first calibration plate is imaged within the field of view of the monocular camera, a coordinate reference point is selected in a depth of field area within the field of view; In the case where the workpiece feature point of the workpiece coincides with the coordinate reference point, obtaining coordinate pair information of the workpiece feature point, wherein the coordinate pair information includes a current reference mechanical coordinate of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and a current reference workpiece coordinate in the workpiece coordinate system of the workpiece; According to the current reference workpiece coordinates and the current reference machine coordinates, a target position motion relationship and a target vector motion relationship are respectively constructed, wherein the target position motion relationship is the position motion relationship between the workpiece and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the workpiece and the multi-axis motion system; The workpiece is calibrated in position and posture according to the target vector motion relationship and the target position motion relationship.

2. The method according to claim 1, characterized in that The step of respectively constructing a target position motion relationship and a target vector motion relationship according to the current reference workpiece coordinates and the current reference machine coordinates includes: Acquire a position-motion relationship between the first calibration plate and the multi-axis motion system, wherein the position-motion relationship is used to characterize a position and posture of the first calibration plate relative to the multi-axis motion system; Determining the current reference calibration coordinates of the coordinate reference point in the calibration coordinate system according to the current reference mechanical coordinates and the position motion relationship; Determining a position and posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates; Constructing the target position motion relationship according to the position motion relationship and the posture relationship; Constructing a vector motion relationship between the first calibration plate and the multi-axis motion system according to the current reference mechanical coordinates and the first external parameters of the monocular camera; Determining a rotational relationship between the first calibration plate and the workpiece in the posture relationship; The target vector motion relationship is constructed according to the vector motion relationship and the rotation relationship.

3. The method according to claim 2, characterized in that A second calibration plate is also placed on the workbench, and the second calibration plate is parallel to the monocular camera and the workpiece, respectively; before determining the posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates, the method further includes: Determining a pose conversion parameter of the workpiece feature point relative to the monocular camera according to a first parameter between the second calibration plate and the monocular camera and a second parameter of the second calibration plate; According to the posture conversion parameters, the current reference workpiece coordinates of the coordinate reference point in the workpiece coordinate system are determined.

4. The method according to claim 2, characterized in that: The determining the position and posture relationship between the first calibration plate and the workpiece according to the current reference calibration coordinates and the current reference workpiece coordinates includes: Acquire a vector motion relationship between the first calibration plate and the multi-axis motion system; and construct a position motion relationship between the first calibration plate and the multi-axis motion system according to the current reference calibration coordinates, the current reference workpiece coordinates and the vector motion relationship.

5. The method according to claim 4, characterized in that The acquiring the position motion relationship between the first calibration plate and the multi-axis motion system includes: When the first calibration plate is imaged within the field of view of the monocular camera, locating the calibration mechanical coordinates of the multi-axis motion system in different positions and acquiring a first target calibration plate image of the first calibration plate; Determining a second external parameter of the monocular camera relative to the first calibration plate according to the first calibration feature points in the plurality of first target calibration plate images; Generate first initial coordinate pair information of the coordinate reference point according to the plurality of calibrated machine coordinates and the plurality of second external parameters, wherein the first initial coordinate pair information is composed of initial reference machine coordinates and initial reference calibrated coordinates; Constructing a position kinematic chain model of the multi-axis motion system according to the initial reference mechanical coordinates and the initial reference calibration coordinates; A position-kinematic relationship between the first calibration plate and the workpiece is constructed according to a position-kinematic chain model and a first model parameter of the position-kinematic chain model.

6. The method according to claim 4, characterized in that The obtaining of the vector motion relationship between the first calibration plate and the multi-axis motion system includes: When the first calibration plate is imaged within the field of view of the monocular camera, locating calibration motion vectors of the multi-axis motion system in different positions and acquiring a second target calibration plate image of the first calibration plate; Determining a third external parameter of the monocular camera relative to the first calibration plate according to the second calibration feature points in the plurality of second target calibration plate images; Generate second initial coordinate pair information of the coordinate reference point according to the plurality of calibration motion vectors and the plurality of third external parameters, wherein the second initial coordinate pair information is composed of an initial reference mechanical motion vector and an initial reference calibration motion vector; Constructing a vector kinematic chain model of the multi-axis motion system according to the initial reference mechanical motion vector and the initial reference calibration motion vector; A vector motion relationship between the first calibration plate and the multi-axis motion system is constructed according to a vector motion chain model and a second model parameter of the vector motion chain model.

7. A workpiece position calibration device, characterized in that: Applied to a multi-axis motion system, the multi-axis motion system includes a working component and a workbench, wherein the working component is provided with a monocular camera, and a first calibration plate is placed on the workbench; the device includes: A selection module, used for selecting a coordinate reference point in a depth of field area within the field of view when the first calibration plate is imaged within the field of view of the monocular camera; an acquisition module, configured to acquire coordinate pair information of the workpiece feature point when the workpiece feature point of the workpiece coincides with the coordinate reference point, wherein the coordinate pair information includes a current reference mechanical coordinate of the coordinate reference point in the mechanical coordinate system of the multi-axis motion system and a current reference workpiece coordinate in the workpiece coordinate system of the workpiece; A construction module, used to construct a target position motion relationship and a target vector motion relationship respectively according to the current reference workpiece coordinates and the current reference machine coordinates, wherein the target position motion relationship is the position motion relationship between the workpiece and the multi-axis motion system, and the target vector motion relationship is the vector motion relationship between the workpiece and the multi-axis motion system; A calibration module is used to calibrate the position and posture of the workpiece according to the target vector motion relationship and the target position motion relationship.

8. A workpiece position and posture calibration system, characterized in that: The system comprises: A working component, wherein a monocular camera is disposed on the working component; A workbench, on which a first calibration plate is placed; A control device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method according to any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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