Workpiece coordinate system calibration method and device and electronic equipment

Abstract

The embodiment of the invention provides a workpiece coordinate system calibration method and device of an industrial robot and electronic device.According to the workpiece coordinate system calibration method, based on virtual feature point position information of a plurality of virtual feature points under a workpiece coordinate system and flange pose information of a mechanical arm flange of the robot under a base coordinate system of the industrial robot, the workpiece coordinate system of the industrial robot is calibrated; and simultaneously solving a calibration result of the workpiece coordinate system and a position calibration result of the tip tool by using an iterative optimization algorithm. According to the method, the workpiece coordinate system and the tip tool are calibrated together, errors caused by first calibration of the tool are avoided, therefore, the overall system errors are reduced, and the precision is higher.

Description

Technical Field

[0001] This application relates to the field of industrial robot technology, and in particular to a workpiece coordinate system calibration method, apparatus and electronic equipment for an industrial robot. Background Technology

[0002] Currently, many industrial robots are capable of machining workpieces. In order to machine a workpiece, it is necessary to calibrate the workpiece coordinate system, that is, to determine the correspondence between the workpiece coordinate system and the robot coordinate system, so that the tool at the end of the industrial robot's robotic arm can be precisely aligned with the position to be machined on the workpiece.

[0003] In related technologies, workpiece coordinate system calibration can be performed using the traditional three-point method in offline simulation software. Existing offline simulation software generally uses a three-point mapping method to calibrate the workpiece coordinate system. For example, the offline simulation software calculates the workpiece coordinate system by acquiring three points in the simulated workpiece and the actual pose of the end effector TCP when it touches the real workpiece at the corresponding three points.

[0004] This method places high demands on the tool tip. When the tool itself is large and lacks a sharp point, using a robot's TCP (Telematics End Capture) to touch the real workpiece results in significant errors between the actual TCP pose and the poses of the simulated workpiece at the three points obtained. This inaccurate point mapping leads to inaccurate workpiece coordinate system calibration, resulting in poor performance. Furthermore, related technologies typically calibrate the tool first before touching the feature points of the real workpiece. This inevitably introduces calibration errors into the workpiece coordinate system calibration; in other words, any error in tool calibration will affect the accuracy of the calculation results.

[0005] In summary, the traditional three-point method and its implementation in offline simulation software not only have high requirements for tool and point accessibility, but also its calibration accuracy is heavily dependent on the pre-calibrated tool accuracy. Any error of the tool will be directly transmitted to the workpiece coordinate system, resulting in a large overall system error, which is difficult to meet the needs of high-precision machining scenarios. Summary of the Invention

[0006] The purpose of this application is to provide a workpiece coordinate system calibration method, apparatus, and electronic device for industrial robots, so as to reduce the error of workpiece coordinate system calibration and improve accuracy. The specific technical solution is as follows:

[0007] This application provides a method for calibrating the workpiece coordinate system of an industrial robot, including:

[0008] A simulation image model of the target workpiece is obtained; the coordinate system of the simulation image model is the workpiece coordinate system.

[0009] Obtain multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system; the number of virtual feature points is ≥3; each virtual feature point corresponds one-to-one with a physical feature point selected by the user on the target workpiece.

[0010] Obtain multiple flange pose information of the robotic arm flange of the industrial robot; the multiple flange pose information is the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool connected to the robotic arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point; the pose information includes: position information and attitude information.

[0011] With the goal of ensuring that the positions of virtual feature points in the base coordinate system are the same as the positions of their corresponding physical feature points in the base coordinate system, and using the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, iterative optimization calculations are performed based on the positional relationship between the robotic arm flange and the tip tool to solve for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool. This solution serves as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

[0012] This application embodiment also provides a workpiece coordinate system calibration device for an industrial robot, including:

[0013] The first acquisition module is used to acquire a simulation image model of the target workpiece; the coordinate system in which the simulation image model is located is the workpiece coordinate system;

[0014] The second acquisition module is used to acquire multiple virtual feature points extracted from the simulation image model and their virtual feature point position information in the workpiece coordinate system. The number of virtual feature points is ≥3. Each virtual feature point corresponds one-to-one with a physical feature point position selected by the user on the target workpiece.

[0015] The third acquisition module is used to acquire multiple flange pose information of the robotic arm flange of the industrial robot. The multiple flange pose information is the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool connected to the robotic arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point. The pose information includes: position information and attitude information.

[0016] The solution module is used to optimize the workpiece coordinate system by taking the position of the virtual feature point in the base coordinate system as the same as the position of its corresponding physical feature point in the base coordinate system. Using the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, it performs iterative optimization calculations based on the positional relationship between the robotic arm flange and the tip tool to solve for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool. This solution serves as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

[0017] This application also provides an electronic device, including:

[0018] Memory, used to store computer programs;

[0019] The processor, when executing the program stored in the memory, implements the above-mentioned workpiece coordinate system calibration method for industrial robots.

[0020] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, provides a method for calibrating the workpiece coordinate system of an industrial robot.

[0021] Beneficial effects of the embodiments in this application:

[0022] This application provides a workpiece coordinate system calibration method, apparatus, and electronic device for an industrial robot. The workpiece coordinate system calibration method uses an iterative optimization algorithm to simultaneously solve for the calibration results of the workpiece coordinate system and the position calibration results of the tip tool, based on the position information of multiple virtual feature points in the workpiece coordinate system and the flange pose information of the robot arm flange in the industrial robot base coordinate system. Since this method does not rely on prior tool calibration and combines multiple feature points spatially distributed on the workpiece, calibrating the workpiece coordinate system together with the tip tool avoids errors caused by prior tool calibration, thus reducing overall system errors and achieving higher accuracy. Furthermore, this method utilizes the pose information of the robot arm flange, which includes not only position information but also attitude information. Compared to related technologies that calibrate the workpiece coordinate system based only on the tool's position information, the calibration results are more accurate.

[0023] Furthermore, compared to related technologies where the number of feature points is limited to three, the embodiments of this application employ an iterative optimization algorithm that allows for an unlimited number of feature points, such as four, five, six, or even more. This increased number of feature points further eliminates the local interference effects of a particular feature point, thereby improving the accuracy of the calibration.

[0024] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0026] Figure 1 This is a schematic diagram of the system structure of the industrial robot used in an application embodiment;

[0027] Figure 2 A flowchart illustrating the workpiece coordinate system calibration method for an industrial robot provided in this application embodiment;

[0028] Figure 3 A schematic diagram illustrating an implementation process of the workpiece coordinate system calibration method for an industrial robot provided in this application.

[0029] Figure 4 for Figure 3 The diagram shows an example of selecting physical feature points for the target workpiece during the implementation process.

[0030] Figure 5a The main interface diagram of the offline simulation software for implementing the workpiece coordinate system calibration method provided in the embodiments of this application;

[0031] Figure 5b In order to be in Figure 5a The image shows an example of offline simulation software selecting virtual feature points.

[0032] Figure 5c for Figure 5a The first state diagram of the point migration calculation interface of the offline simulation software is shown.

[0033] Figure 5d for Figure 5c The second state diagram of the point migration calculation interface is shown.

[0034] Figure 5e for Figure 5a The image shown is a status diagram of the main interface when error information is displayed.

[0035] Figure 5f for Figure 5a The main interface shown below displays a status image indicating successful data synchronization.

[0036] Figure 6 This is a flowchart illustrating the workpiece coordinate system calibration method provided in the embodiments of this application, and the process of an industrial robot machining a workpiece.

[0037] Figure 7 This is a schematic diagram illustrating an implementation process of an industrial robot machining a workpiece based on the workpiece coordinate system calibration method provided in this application.

[0038] Figure 8 for Figure 7 During the process shown, the offline simulation software generates an interface diagram of the workpiece machining path;

[0039] Figure 9 for Figure 7 During the process shown, the offline simulation software displays the interface diagram of workpiece processing;

[0040] Figure 10 This is a schematic diagram of the workpiece coordinate system calibration device for an industrial robot provided in an embodiment of this application;

[0041] Figure 11 This is a schematic diagram of the structure of an electronic device for an industrial robot provided in an embodiment of this application. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0043] In related technologies, the calibration of the workpiece coordinate system is based on the traditional three-point method. The three-point method is further divided into the origin method and the perpendicular foot method, which are conventional methods for calibrating the workpiece coordinate system. In some cases, the workpiece coordinate system may also be referred to as the user coordinate system.

[0044] Origin method: First, operate the robotic arm so that its end effector TCP moves to the origin of the workpiece coordinate system and record the position as P1. Then, operate the robotic arm so that its end effector TCP moves to any point on the x-axis of the workpiece coordinate system and record it as P2. Finally, operate the robotic arm so that it moves to any point in the first quadrant of the xoy plane of the workpiece coordinate system and record it as P3. Then the position and orientation of the workpiece coordinate system can be calculated.

[0045] remember Let nx be the attitude direction vector of the workpiece coordinate system, where nx is the attitude vector in the x-direction, ny is the attitude vector in the y-direction, and nz is the attitude vector in the z-direction.

[0046]

[0047]

[0048]

[0049] Origin position Therefore, the homogeneous matrix representation of the workpiece coordinate system u in the world coordinate system w is: Then, it is converted according to the Euler pose form. Where R is the rotation matrix, rx is the rotation angle in the x-direction, ry is the rotation angle in the y-direction, and rz is the rotation angle in the z-direction.

[0050] The perpendicular method is similar to the origin method, except that the origin is not P1, but rather the line from P3 to the origin. The dangling foot.

[0051] Traditional three-point calibration of the workpiece coordinate system relies on the pose of the end effector TCP tip, which has limitations such as the origin being unreachable or the y-axis being unreachable. Furthermore, inaccurate tool calibration can lead to calibration errors in the workpiece coordinate system. As described in the background section, related technologies using offline simulation software to calibrate the workpiece coordinate system using the traditional three-point method are also based on this traditional method. The software calculates the workpiece coordinate system by acquiring three points in the simulation and the TCP pose of the end effector TCP when the robot uses its end effector TCP to press the corresponding three points on the actual workpiece.

[0052] The principle is also very simple. It is known that the coordinates of the three feature points i in the workpiece coordinate system u during the simulation are... Three non-collinear points can be used to construct a local coordinate system using the origin method. Three non-collinear points construct a local coordinate system. The two local coordinate systems are calibrated in the industrial robot's base coordinate system r through a workpiece coordinate system u. The conversion can be completed:

[0053]

[0054] Seek

[0055]

[0056] The calibration information of the workpiece coordinate system u, expressed in Euler pose form, can be obtained from the homogeneous matrix and configured into the industrial robot. This solution effectively solves the problem of the origin and Y-axis being unreachable in the original three-point method, and thus has better feasibility for on-site implementation. However, the effect is still poor when there are large tools that are difficult to map to points. Moreover, this solution uses the tool end-effector TCP pose, so if the tool has errors, the calculation results will also be affected, meaning that the error problem still exists.

[0057] To improve the accuracy of workpiece coordinate system calibration for industrial robots, this application provides a workpiece coordinate system calibration method, apparatus, and electronic device for industrial robots. These will be described in detail below.

[0058] First, the system of the industrial robot applied in the embodiments of the application will be described.

[0059] See Figure 1 , Figure 1 This is a schematic diagram of the system structure of an industrial robot used in an embodiment of the application. Figure 1 As shown, the system includes: a controller connected to the industrial robot, a host computer connected to the controller via a network, and a teach pendant connected to the controller. The host computer can be equipped with offline simulation software, which is used to calibrate workpiece coordinates and process the industrial robot's workpiece machining. Figure 1 As shown, the host computer's monitor can display the interface of the offline simulation software; the end of the industrial robot's robotic arm can be connected to a pointed tool via a flange.

[0060] Next, the workpiece coordinate system calibration method for industrial robots provided in this application embodiment will be described in detail. This method mainly employs a multi-point mapping iterative optimization algorithm, specifically:

[0061] See Figure 2 , Figure 2 This is a flowchart illustrating the workpiece coordinate system calibration method for an industrial robot provided in an embodiment of this application. Figure 2 As shown, the process includes the following steps:

[0062] Step S201: Obtain a simulation image model of the target workpiece; the coordinate system of the simulation image model is the workpiece coordinate system.

[0063] The key point in the workpiece coordinate system calibration method of this application is solving the pose of the workpiece coordinate system in the base coordinate system. Specifically, the coordinate systems involved in the solution process are as follows: Figure 1 As shown, the coordinate system in which the simulation image model displayed on the monitor is located is the workpiece coordinate system; the base coordinate system refers to the pose of the industrial robot base in the world coordinate system; and the flange coordinate system refers to the pose of the robotic arm flange in the base coordinate system.

[0064] It should be noted that in this step, the simulation image model can be imported from external software into the offline simulation software, and can be displayed or not displayed as needed.

[0065] Step S202: Obtain multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system.

[0066] The number of virtual feature points is ≥3; each virtual feature point corresponds one-to-one with a physical feature point selected by the user on the target workpiece.

[0067] In this step, the offline simulation software can display the simulation image model for the user to select virtual feature points, or it can choose not to display the simulation image model and allow the user to directly input the positions of the virtual feature points. This application embodiment does not impose any limitations.

[0068] In this embodiment, the traditional three-point method is not used for workpiece coordinate system calibration. Instead, an iterative optimization approach is employed for the joint calibration of the workpiece coordinate system and the tip tool. Therefore, the number of feature points is not limited by the three-point method; for example, four, five, six, or even more. Theoretically, the more feature points, the more accurate the calibration. The number of feature points can be selected based on the calibration accuracy requirements and computational complexity, and this embodiment does not impose any limitations.

[0069] Step S203: Obtain multiple flange pose information of the robotic arm flange of the industrial robot.

[0070] The multiple flange pose information refers to the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool connected to the robotic arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point; the pose information includes: position information and attitude information.

[0071] In this embodiment, the user can extract corresponding virtual feature points from the simulation image model based on physical feature points pre-selected on the target workpiece. Alternatively, multiple virtual feature points can be selected on the simulation image model first, and then the robotic arm can be controlled to move so that its tip tool aligns with the physical feature points corresponding to each virtual feature point to obtain flange pose information.

[0072] Step S204: Taking the position of the virtual feature point in the base coordinate system being the same as the position of its corresponding physical feature point in the base coordinate system as the optimization objective, and using the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, iterative optimization calculations are performed based on the positional relationship between the robotic arm flange and the tip tool to solve for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool, which serves as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

[0073] The workpiece coordinate system calibration method provided in this application, based on the position information of multiple virtual feature points in the workpiece coordinate system and the flange pose information of the robot arm flange in the industrial robot base coordinate system, uses an iterative optimization algorithm to simultaneously solve for the calibration results of the workpiece coordinate system and the position calibration results of the tip tool. Since this method does not rely on prior tool calibration and combines multiple feature points spatially distributed on the workpiece, calibrating the workpiece coordinate system together with the tip tool avoids errors caused by prior tool calibration, thus reducing overall system errors and achieving higher accuracy. Furthermore, this method utilizes the pose information of the robot arm flange, which includes not only position information but also attitude information. Compared to related technologies that calibrate the workpiece coordinate system based only on the tool's position information, the calibration results are more accurate.

[0074] In some embodiments, the calibration results can be synchronized to the industrial robot's controller. Synchronization can be achieved through one of the following two synchronization processes. Specifically,

[0075] The first synchronization process involves synchronizing the first calibration result of the workpiece coordinate system to the controller of the industrial robot; or, based on the known pose information of the robot's base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, calculating the second target pose information of the workpiece coordinate system in the world coordinate system, and using this as the second calibration result, synchronizing the second calibration result to the controller of the industrial robot; thereby enabling the controller to control the industrial robot based on either the first or the second calibration result. The known pose information of the industrial robot's base coordinate system in the world coordinate system is determined after the industrial robot is installed and remains unchanged during its workpiece processing.

[0076] The second synchronization process involves synchronizing the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool to the controller of the industrial robot; or, based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, calculating the second target pose information of the workpiece coordinate system in the world coordinate system as the second calibration result, and synchronizing the second calibration result and the position calibration result of the tip tool to the controller of the industrial robot; thereby enabling the controller to control the industrial robot based on the first calibration result or the second calibration result, and to verify the tip tool based on the position calibration result.

[0077] In practical applications, industrial robots themselves set the position information of their tip tools. Therefore, in some embodiments, the first synchronization process described above can be used, which only synchronizes the first or second calibration result to the industrial robot's controller. In other embodiments, the second synchronization process described above is used, which also synchronizes the position calibration result of the tip tool to the industrial robot's controller. This allows for verification of the tip tool based on the position calibration result. For example, it can verify whether the tip tool used for workpiece coordinate system calibration is consistent with the tip tool connected to the industrial robot.

[0078] In this embodiment of the application, the optimal solution for solving the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool may specifically include:

[0079] Substitute the initial values ​​of the set workpiece coordinate system and the tip tool position, along with the known parameters, into the preset residual calculation function to calculate the initial function value of the residual calculation function; the residual calculation function is used to calculate the error value between the position of the virtual feature point in the base coordinate system and the position of its corresponding physical feature point in the base coordinate system.

[0080] With the goal of making the residual calculation function equal to 0, the optimal solution for the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool is obtained by using the Jacobian matrix constructed based on the residual calculation function and a preset iterative algorithm.

[0081] The residual calculation function and Jacobian matrix are derived in advance according to the following steps:

[0082] Define the homogeneous pose matrix formulas for the workpiece coordinate system u under the robot base coordinate system r, the homogeneous pose matrix formulas for the flange of the robot arm under the robot base coordinate system r, the homogeneous pose matrix formulas for the tool at the end of the flange under the flange coordinate system, and the homogeneous pose matrix formulas for the points under the workpiece coordinate system u.

[0083] With the optimization objective of ensuring that the position of the virtual feature point in the base coordinate system is the same as the position of its corresponding physical feature point in the base coordinate system, the residual calculation function and the solution formula of the residual calculation function are defined using the defined homogeneous matrix formulas of each pose. The solution formula of the residual function includes: the first target pose information formula of the workpiece coordinate system in the base coordinate system and the position information formula of the tip tool.

[0084] The Jacobian matrix is ​​constructed based on the solution formula of the residual calculation function.

[0085] The residual calculation function is as follows:

[0086]

[0087]

[0088] The Jacobian matrix is:

[0089]

[0090] in,

[0091] ;

[0092] I is the identity matrix; To perform antisymmetric matrix operations on three-dimensional vectors;

[0093] in, Let be the position coordinates of the flange corresponding to a certain physical feature point i in the robot's base coordinate system r. This refers to the attitude information of the robotic arm flange corresponding to the physical feature point i in the robot's base coordinate system r. These are the position coordinates of the tool in the flange coordinate system. Let be the position coordinates of the workpiece coordinate system u in the base coordinate system r. The orientation information of the origin of the workpiece coordinate system u in the robot base coordinate system r; Let i be the position coordinates of a virtual feature point i in the workpiece coordinate system u; i represents the feature point number.

[0094] In some embodiments, iterative optimization can be performed using the LM (Levenberg-Marquardt) damping method based on the initial values ​​of the set workpiece coordinate system and tool position, the known parameters, and the Jacobian matrix. Of course, other iterative algorithms can also be used for iterative optimization, and this application does not impose any limitations. In this embodiment, the LM damping method is used for iterative optimization, which involves relatively little computation, has a fast solution speed, and provides relatively accurate iteration results.

[0095] In some embodiments, for cases where it is necessary to synchronize the second calibration result to the controller of the industrial robot, the method further includes:

[0096] The pose homogeneity matrix formulas for the robot base coordinate system in the world coordinate system, the pose homogeneity matrix formulas for the first target pose information, and the pose homogeneity matrix formulas for the second target pose information are predefined.

[0097] Based on the pose homogeneous matrix formula of the known pose information and the pose homogeneous matrix formula of the first target pose information, as well as the transformation relationship between the known pose information and the first target pose information, the position calculation formula and attitude calculation formula in the second target pose information are derived in advance.

[0098] The step of calculating the second target pose information of the workpiece coordinate system in the world coordinate system based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system includes: calculating the second target pose information based on the known pose information and the first target pose information, using the position calculation formula and the attitude calculation formula.

[0099] Specifically, the derivation of the residual calculation function and the Jacobian matrix includes the following three steps:

[0100] (1) Create equality constraints

[0101] Define the pose information for each coordinate system, including:

[0102] For the case where the first target pose information of the workpiece coordinate system in the base coordinate system is used as the first calibration result of the workpiece coordinate system and the calibration result of the tip tool:

[0103] The pose homogeneous matrix of the workpiece coordinate system u in the robot base coordinate system r is denoted as... ;in, The orientation information (i.e., rotation matrix) of the origin of the workpiece coordinate system u in the robot base coordinate system r. Let be the position coordinates of the origin of the workpiece coordinate system u in the robot base coordinate system r; the pose of the workpiece coordinate system u under the robot base coordinate system r is the first target pose information to be solved.

[0104] The homogeneous matrix of the flange pose of the robotic arm in the robot's base coordinate system r is denoted as: ;in, Let i be the attitude information (i.e., rotation matrix) of the flange corresponding to a certain physical feature point i in the robot's base coordinate system r. Let i be the position coordinates of the flange corresponding to the physical feature point i in the robot's base coordinate system r; i represents the feature point number; i is the aforementioned multiple flange pose information of the industrial robot.

[0105] The homogeneous pose matrix of the tool at the end of the flange to the flange is denoted as: ;in, This refers to the tool's attitude information (i.e., rotation matrix) in the flange coordinate system. These are the position coordinates of the tool in the flange coordinate system;

[0106] The homogeneous pose matrix of a point in the workpiece coordinate system u is denoted as: ;in, This refers to the orientation information (i.e., rotation matrix) of a virtual feature point i in the workpiece coordinate system u. The coordinates of the virtual feature point i in the workpiece coordinate system u; i represents the feature point number; that is, the virtual feature point position information of each of the aforementioned virtual feature points.

[0107] For the second target pose information in the workpiece coordinate system within the world coordinate system, as a second calibration result, the following definition is also required:

[0108] The pose homogeneous matrix of the workpiece coordinate system u in the world coordinate system w is denoted as... ;in, This represents the orientation information (i.e., rotation matrix) of the origin of the workpiece coordinate system u in the world coordinate system w. Let be the position coordinates of the origin of the workpiece coordinate system u in the world coordinate system w; the pose of the workpiece coordinate system u in the world coordinate system w is the pose information of the second target to be solved.

[0109] The homogeneous pose matrix of the robot's base coordinate system r in the world coordinate system w is fixed and is denoted as follows: ;in, This represents the attitude information (i.e., rotation matrix) of the robot's base origin (the origin of the robot's base coordinate system r) in the world coordinate system w. The coordinates of the robot's base origin (the origin of the robot's base coordinate system r) in the world coordinate system w; that is, the previously known pose information.

[0110] Thus, based on the premise that the pose of virtual feature points in the world coordinate system should be the same as that of physical feature points in the world coordinate system, it can be easily deduced that the pose of feature points in the world coordinate system w is:

[0111] (Formula 1)

[0112] Based on the known pose information of the robot's base coordinate system in the world coordinate system The first target pose information of the workpiece coordinate system in the base coordinate system. This allows us to convert the workpiece coordinate system into the world coordinate system to obtain the pose information of the second target. :

[0113] (Formula 2)

[0114] The location calculation formula is as follows: The attitude calculation formula is: .

[0115] Additionally, the following is obtained by transforming the workpiece coordinate system's pose in the robot's base coordinate system:

[0116] (Formula 3)

[0117] This yields the position equation: = + (Formula 4)

[0118] (2) Extract the optimization objective and construct the optimization problem.

[0119] Construct the optimization problem (i.e., the optimization function). =0 (Formula 5)

[0120] Extract the objects to be optimized

[0121] It should be noted that the optimization problem here uses a rotation matrix, so the optimization object can only be... However, during the optimization process, the intermediate variable of axis angle needs to be used to replace the rotation matrix; otherwise, the calculation becomes complicated.

[0122] The specific calculations yielded nine values, including: The coordinates of the origin of the workpiece coordinate system u in the three directions of the robot base coordinate system r are the first, second, and third values ​​in the calculation results. The rotation matrices of the workpiece coordinate system u origin in the robot base coordinate system r in the three directions, converted to axis-angle form are: In the calculation results, these are the 4th, 5th, and 6th values; and The coordinates of the tip tool in the three directions in the flange coordinate system are the 7th, 8th, and 9th values ​​in the calculation results;

[0123] Wherein, rotation matrix Use during optimization Functions converted to axis-angle representation:

[0124] in It is the axis angle.

[0125] (3) Construction of Jacobi matrix

[0126] in,

[0127]

[0128] I is the identity matrix; To perform antisymmetric matrix operations on three-dimensional vectors.

[0129] The solution method is explained below.

[0130] When the first target pose information of the workpiece coordinate system in the base coordinate system is used as the first calibration result of the workpiece coordinate system and the calibration result of the tip tool, only iterative optimization is needed to obtain the first calibration result of the workpiece coordinate system and the calibration result of the tip tool. Specifically, this can include:

[0131] Iterative methods, such as the LM damping method, are employed using least squares approaches.

[0132] First, in the flange coordinate system, set the initial values ​​for the tip tool and the tool coordinate system:

[0133] =[0 0 150]', , ;

[0134] Here, mean() is the mean function.

[0135] Then, the LM damping method is used iteratively. The LM damping method overcomes the coupling characteristics of point selection, where... The step size is variable; as the error decreases, Decrease; when the error increases, Increase

[0136] ; ;

[0137]

[0138]

[0139] Where dx is the iteration step size; The error is the value calculated during the iteration process. The value; For data update functions;

[0140] After calculating the change dx of the optimization objective, the value of the optimization objective is updated, where and These are coordinate values, which can be directly added together for calculation:

[0141] j=1,2,3,7,8,9, where j is the index in the calculation result of x.

[0142] in Since the objective is a rotation matrix, and the results of the above optimization calculations... Since it's a rotation vector, it needs to be matrixed and then left-multiplied.

[0143] The vector to be rotated Convert to rotation matrix .

[0144]

[0145]

[0146] The above process updates the 1st to 9th specific values ​​of variable x. It is a function that converts a rotation vector into a rotation matrix. () is a function that converts a rotation matrix into a rotation vector.

[0147] The `diag` function in Matlab simulations is used to construct a diagonal matrix, a square matrix whose off-diagonal elements are all 0, or to return the diagonal elements of a matrix as a vector.

[0148] For cases where the second target pose information of the workpiece coordinate system in the world coordinate system is used as the second calibration result, it is necessary to further solve for the workpiece coordinate system in the world coordinate system.

[0149] In robotic applications, if the workpiece coordinate system is built in the world coordinate system, then it is necessary to solve the workpiece coordinate system pose in the world coordinate system.

[0150]

[0151]

[0152]

[0153] Thus, based on the known pose information of the robot's base coordinate system in world coordinates... The first target pose information of the workpiece coordinate system in the base coordinate system. It can quickly determine the pose of the workpiece coordinate system in the world coordinate system. .

[0154] The calibration of the workpiece coordinate system and the tip tool can be completed through the above iterative process.

[0155] In practice, Figure 2 All steps in the method flow shown can be generated by Figure 1 The system shown is executed by a host computer that communicates with the controller of the industrial robot; or, by... Figure 1 The teach pendant connected to the controller of the industrial robot in the system shown performs the operation. This application does not impose limitations on the embodiments described.

[0156] The following describes in detail the specific implementation process of the workpiece coordinate system calibration method provided in this application embodiment, taking the example that all steps are executed by a host computer that is connected to the controller of the industrial robot.

[0157] like Figure 1 As shown, in this embodiment, the workpiece coordinate system calibration method is implemented by offline simulation software installed in the host computer. In this embodiment, by efficiently combining the offline simulation software with the real environment, the user operation process can be simplified, and the accurate calibration of the workpiece coordinate system and the tool can be ensured. The specific implementation process is as follows: Figure 3 As shown. Figure 3 This application provides an embodiment of a workpiece coordinate system calibration method for an industrial robot, the process of which includes:

[0158] Step S301: Assess the operability of the field tools.

[0159] In this embodiment, the tip tool for the robotic arm flange connection can be: a machining tool with a tip for machining the target workpiece; or a calibration tool with a tip installed at the end of the machining tool for calibration. In practical applications, the calibration tool is removed after the workpiece coordinate system calibration is completed.

[0160] This application first evaluates the machining tool at the end effector of an industrial robot. Specifically, it assesses whether the machining tool has a distinctive tip that can contact certain feature points on the workpiece without collision. If not, a needle-like calibration tool can be installed on the existing machining tool. The tip can be relatively long, thus avoiding the collision risk caused by the tool's large size. Figure 1 As shown, an extended tip tool is installed at the end of the robot flange or existing machining tool to facilitate contact with feature points on the target workpiece in order to obtain flange pose information.

[0161] When the end effector of an industrial robot has a distinctive tip, an iterative optimization algorithm is used to simultaneously solve for the calibration results of the workpiece coordinate system and the tip tool. These results are then synchronized into the controller of the industrial robot. The calibration results of the tip tool can be used to verify and quickly correct the calibration results of the industrial robot itself.

[0162] In cases where the end effector of an industrial robot lacks a distinctive tip, and a needle-like calibration tool is installed on an existing machining tool, an iterative optimization algorithm is used to simultaneously solve for the calibration results of the workpiece coordinate system and the position calibration results of the needle-like calibration tool, which are then synchronized into the controller of the industrial robot.

[0163] In this embodiment, new offline simulation software can be used to jointly calibrate the workpiece coordinate system and the cutting tool. Then, the industrial robot only uses the calibrated workpiece coordinate system results to process the workpiece. On the one hand, this eliminates the cumbersome step of calibrating the tool first in related technologies, avoiding local errors in tool calibration; on the other hand, the rapid joint calibration method makes the calibration results of the workpiece coordinate system less affected by the tool.

[0164] As can be seen from the aforementioned residual calculation function, the tool position, as an unknown, is solved simultaneously with the workpiece coordinate system. The specific position of the tool has no impact on the calibration results of the workpiece coordinate system. Therefore, using the calibration tool has little effect on the calibration results of the workpiece coordinate system, and the calibration of the workpiece coordinate system does not depend on the calibration results of the tool position. After removing the calibration tool, the calibration results of the workpiece coordinate system can still be used.

[0165] Compared with the existing technology that uses the "tool tip position" to calibrate the tool first, and then uses the tool calibration result to calibrate the coordinate system, where the calibration result is deeply bound to the tool tip position and directly affects the accuracy of the calibration result, the workpiece coordinate system calibration in this embodiment does not depend on the tool position calibration result, avoids the error caused by calibrating the tool first, thus reducing the overall system error and achieving higher accuracy.

[0166] Therefore, the workpiece coordinate system calibration method provided in this embodiment can be adapted to scenarios with indistinct contours and tools without sharp points, and significantly improves the accuracy of calibration.

[0167] Step S302: Select multiple virtual feature points and obtain the virtual feature point location information of each virtual feature point.

[0168] Extract at least three, but typically five, significant feature points from the target workpiece. These feature points can be corner points, center points of circles, midpoints of paths, outermost points of arcs, etc.

[0169] Taking a washbasin as an example, the selection of its physical feature points is detailed in [reference needed]. Figure 4 , Figure 4 for Figure 3 The diagram illustrates an example of selecting physical feature points for the target workpiece during the implementation process. Figure 4 As shown, users can select physical feature points at the outline protrusions, center of the round hole, center of the circle, outer perimeter of the rounded corner, and straight-arc connection of the washware. The number can be 3 or more, but 5 is generally selected.

[0170] Import the simulated image model of the target workpiece into offline simulation software for simulation. For example... Figure 1As shown, the user extracts multiple virtual feature points from the simulation image model, with each virtual feature point corresponding one-to-one with a physical feature point. At this time, the coordinate system of the simulation image model is the workpiece coordinate system. In some embodiments, the user can also extract multiple virtual feature points by directly inputting coordinates instead of selecting them on the display interface. The offline simulation software can obtain the position information of each virtual feature point in the workpiece coordinate system. Since multiple virtual features are on the simulation image model, only the position information of the virtual feature points is obtained at this time, without attitude information. The position information of these virtual feature points can be represented as... .

[0171] Step S303: Obtain the flange pose of multiple physical feature points.

[0172] In this step, the multiple flange pose information refers to the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool of the robotic arm flange connection is sequentially aligned with the physical feature points corresponding to each virtual feature point.

[0173] Based on the above steps S301, the pinpoint was installed (or a tool tip was used directly, or the TCP tool was used directly), and in step S302, the location information of the virtual feature points in the simulation was obtained. Then, a robotic arm movement command can be sent to the industrial robot to operate the robotic arm and allow its tip to touch a physical feature point on the workpiece in any orientation. The pose of the robot flange in the base coordinate system r is then denoted as... Where rx is the rotation angle in the x-direction, ry is the rotation angle in the y-direction, and rz is the rotation angle in the z-direction.

[0174] In this embodiment, after selecting virtual feature points, a robotic arm movement command is sent to the industrial robot, and the flange pose of each physical feature point is received from the industrial robot after executing the robotic arm movement command.

[0175] In other embodiments, the flange pose of each physical feature point can be obtained by sending a robotic arm movement command to the industrial robot before selecting virtual feature points, and then the industrial robot executes the robotic arm movement command to touch each physical feature point and provides feedback and saves the result.

[0176] Step S304: Perform iterative optimization calculations to solve for the first target pose information of the workpiece coordinate system in the base coordinate system. And the cutting-edge TCP currently in use, namely .

[0177] In some embodiments, the second target pose information of the workpiece coordinate system in the world coordinate system can be calculated based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, and used as the second calibration result.

[0178] Next, we will continue with the target workpiece as... Figure 4 Taking the shown toiletries as an example, combined with Figures 5a to 5f The offline simulation software used in this embodiment will be described in detail. Specifically, Figure 5a The main interface diagram of the offline simulation software for implementing the workpiece coordinate system calibration method provided in the embodiments of this application; Figure 5b In order to be in Figure 5a The image shows an example of offline simulation software selecting virtual feature points. Figure 5c In order to be in Figure 5a The first state diagram of the point migration calculation interface of the offline simulation software is shown. Figure 5d for Figure 5c The second state diagram of the point migration calculation interface is shown. Figure 5e for Figure 5a The image shown is a status diagram of the main interface when error information is displayed. Figure 5f for Figure 5a The main interface shown is a status image indicating that data synchronization was successful.

[0179] like Figure 5a As shown, the offline simulation software used in this embodiment provides functions such as scene building, process package selection, path programming, task simulation, program editing, process parameter selection, coordinate system calibration and transformation, tool configuration, automatic attitude planning configuration, and OLP (offline simulation software) point migration calculation. Specifically, the scene building interface allows for importing simulation image models, while the point migration calculation interface allows for the picking and calculation of virtual and physical feature points. It should be noted that the "real user coordinate system" in the figure refers to the aforementioned workpiece coordinate system. The user coordinate system refers to the local coordinate system set by the user, generally with the world coordinate system as the reference. The workpiece coordinate system and the user coordinate system have the same effect. The process is optional. Figure 5a The image shows the grinding process; other processing techniques such as welding can also be selected.

[0180] After the simulation image model is imported, virtual feature points can be selected on the simulation image model in the interface. For example... Figure 5b As shown, the virtual feature points selected by the user include: the center of the circle, the contour protrusion point, the outer perimeter of the fillet, the straight-line arc connection, and the center of the circular hole. The positions of these virtual feature points on the workpiece are... Figure 4 The physical feature points selected by the user correspond one-to-one with the positions on the workpiece.

[0181] See Figure 5c After the user selects several virtual feature points and obtains multiple flange pose information of the robotic arm flange reported by the industrial robot, the offline simulation software can save the virtual feature point position information of each virtual feature point and the flange pose information of each physical feature point. Then, the feature points can be obtained in the point migration calculation interface, and point migration calculation can be performed.

[0182] In some embodiments, a virtual feature point identifier can be set for each virtual feature point during the extraction of virtual feature points, and a corresponding physical feature point identifier can be set for each physical feature point; after obtaining multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system, the position information of each virtual feature point is saved using the virtual feature point identifier as an index; after obtaining multiple flange pose information of the robotic arm flange of the industrial robot, the flange pose information corresponding to each physical feature point is saved using the physical feature point identifier as an index.

[0183] like Figure 5c and Figure 5d As shown, the point migration calculation interface includes, from top to bottom: a feature point addition button, a feature point list display area, a current feature point information display area, a calculation button, a calculation result information display area, and a data synchronization button (the "Real User Coordinate System and Tool Data Synchronization Controller" button in the figure). When the add button is triggered, the user can add the feature point identifiers of each virtual feature point and the identifiers of each physical feature point to the two point lists.

[0184] Specifically, users can click the "Add" button, and each operation will generate two columns of data in the table below: one column is used to add the coordinates of virtual feature points of the simulation image model in the offline simulation software (the coordinates are obtained through the graphical interface picking operation, such as...). Figure 5b Example); another column is used to add the flange pose corresponding to the physical feature points in the real environment. Virtual feature points in offline simulation software can have their coordinate data automatically captured by the user directly selecting key locations on the simulation image model, ensuring intuitiveness and accuracy of the operation. After adding, as shown... Figure 5a As shown, the two columns display virtual feature point identifiers (Point) and physical feature point identifiers (RealPoint), respectively.

[0185] When a user selects a virtual feature point identifier in the feature point list, the system searches for the corresponding virtual feature point position information from the saved virtual feature point position information and displays the virtual feature point position information in the workpiece coordinate system in the current feature point information display area. When a user selects a physical feature point identifier in the feature point list, the system searches for the corresponding physical feature point position information from the saved flange pose information and displays the flange pose corresponding to the physical feature point in the current feature point information display area. That is, the pose information of the robotic arm flange in the industrial robot base coordinate system when the robotic arm tip tool touches the physical feature point.

[0186] like Figure 5d As shown, when the user selects RealPoint1, i.e., clicks... Figure 5d In the case of RealPoint1 displayed in the image, the current feature point information display area shows: the reference coordinate system of the current point information is the base coordinate system of the industrial robot, as well as the position coordinates and attitude information of the physical feature point 1. For example... Figure 5e As shown, when the user selects virtual feature point 2 (Point2), that is, clicks... Figure 5e In the case of Point2, the current feature point information display area displays: the reference coordinate system of the current point information is the base coordinate system of the industrial robot, as well as the position coordinate value and attitude information of virtual feature point 2.

[0187] When the first target pose information of the workpiece coordinate system in the base coordinate system is used as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool, if the user triggers the calculation button, the offline simulation software will perform the step of solving the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool, and display the calibration result of the workpiece coordinate system and the position calibration result of the tip tool in the calculation result information display area.

[0188] When the second target pose information of the workpiece coordinate system in the world coordinate system is used as the second calibration result, if the user triggers the calculation button, the offline simulation software will perform the step of solving for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool. Based on the known pose information of the robot base coordinate system in the world coordinate system, the software will calculate the second target pose information of the workpiece coordinate system in the world coordinate system as the final application result. The final calibration result of the workpiece coordinate system and the position calibration result of the tip tool will be displayed in the calculation result information display area.

[0189] When the user triggers the data synchronization button, the offline simulation software synchronizes the calibration results of the workpiece coordinate system and the position calibration results of the tip tool to the controller of the industrial robot. As mentioned above, the offline simulation software can synchronize the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool to the controller of the industrial robot. Alternatively, the transformed workpiece coordinate system in the world coordinate system can be used as a second calibration result and synchronized together with the position calibration result to the controller of the industrial robot. In other embodiments, only the first calibration result or the second calibration result may be synchronized to the controller of the industrial robot.

[0190] In addition, in some embodiments, after performing the step of solving the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool, the optimal solution of the first target pose information and the position information of the tip tool is further substituted into a preset residual calculation function for calculation to obtain the error information of each virtual feature point and its corresponding physical feature point.

[0191] Thus, when displaying the calibration results of the workpiece coordinate system and the position calibration results of the tip tool in the display area, such as Figure 5e As shown, error information between each virtual feature point and the physical feature point can be further displayed through pop-up windows or other methods. This allows users to determine whether the error meets preset requirements based on the error information. If the requirements are not met, more virtual feature points and their corresponding physical feature points can be selected to re-perform the workpiece coordinate system calibration for correction. After the calibration results of the workpiece coordinate system and the calibration results of the tip tool are synchronized, the data synchronization results can be further displayed through pop-up windows or other methods. Figure 5f As shown, a pop-up window will appear indicating that data synchronization was successful.

[0192] Therefore, the calibration method for the industrial robot workpiece coordinate system provided in this application can realize the rapid mapping and migration of simulated points (i.e., virtual feature points) and actual points (i.e., physical feature points), as well as the rapid correction of the coordinate system of the actual points.

[0193] Next, the process of industrial robots processing workpieces will be explained.

[0194] See Figure 6 , Figure 6 This is a flowchart of an industrial robot machining a workpiece, based on the workpiece coordinate system calibration method provided in the embodiments of this application; the flowchart includes:

[0195] Step S601: Determine the machining path of the tool at the end of the robotic arm of the industrial robot for the target workpiece in the workpiece coordinate system;

[0196] The process of industrial robot processing workpieces provided in the embodiments of this application can be performed by... Figure 1 The host computer in the industrial robot system shown executes the process. The host computer is equipped with offline simulation software, which contains programs for implementing the workpiece coordinate system calibration method described above, as well as programs for controlling the industrial robot to process the target workpiece.

[0197] In this step, the simulation image model of the target workpiece can be imported into offline simulation software. The offline simulation software extracts the contour line of the target workpiece, and further generates the machining path and the robot control machining process program on the contour line, generating the corresponding robot engineering. At this time, all the point information that needs to be processed in the simulation image model is in the workpiece coordinate system.

[0198] Step S602: Perform the above-described workpiece coordinate system calibration method to obtain the calibration results of the workpiece coordinate system and the position calibration results of the tip tool.

[0199] Once the machining path for the target workpiece is determined, the difference between the actual industrial robot layout and the simulation makes it difficult for the robot to perform machining precisely on the actual workpiece during execution. Therefore, accurately executing the offline simulation path on the target workpiece is a technical challenge. The workpiece coordinate system calibration method described above ensures a precise correspondence between virtual feature points and physical feature points, thus guaranteeing the accurate correspondence between the virtual feature points of the offline simulation path and the physical feature points of the target workpiece, thereby solving the technical challenge of accurately executing the offline simulation path on the target workpiece.

[0200] Step S603: The robot engineering, workpiece coordinate system calibration results, and tip tool position calibration results are sent to the industrial robot's controller, so that the controller controls the industrial robot to process the target workpiece based on the processing path, workpiece coordinate system calibration results, and tip tool calibration results. The robot engineering includes the robot's specific processing path and control instructions.

[0201] In this step, the offline simulation software can generate configuration information based on the calibration results of the workpiece coordinate system and the calibration results of the cutting tool, and then provide the robot engineering and configuration information to the controller of the industrial robot for execution.

[0202] In this embodiment, since step S602 uses the aforementioned workpiece coordinate system calibration method to obtain the calibration results of the workpiece coordinate system and the tip tool, this ensures that the position of the virtual feature point in the base coordinate system is the same as the position of the physical feature point in the base coordinate system, or that the pose of the virtual feature point in the world coordinate system is the same as the pose of the physical feature point in the world coordinate system. Therefore, this ensures that the industrial robot can accurately perform machining operations on the target workpiece according to the machining path generated by the offline simulation software, thereby guaranteeing the machining quality of the target workpiece.

[0203] The following describes in detail the specific implementation process of workpiece processing, taking the need to deburr and smooth the contours of the aforementioned washbasin as an example. In this embodiment, for washbasins with curvature and gradually changing curvature, offline simulation software can be used to simplify the operation.

[0204] like Figure 1 As shown in this embodiment, the process of the industrial robot processing the workpiece is implemented by offline simulation software installed in the host computer.

[0205] The specific implementation process, such as Figure 7 As shown, Figure 7 This is a schematic diagram illustrating an implementation process of an industrial robot machining a workpiece based on the workpiece coordinate system calibration method provided in this application; the process includes:

[0206] Step S701: Generate the on-site process path and robot engineering.

[0207] The on-site process path in this step is the aforementioned processing path. The implementation of this step can be found above. Figure 6 Detailed explanation of step S601.

[0208] like Figure 8 As shown, Figure 8 for Figure 7 As shown in the diagram, the offline simulation software generates an interface diagram of the workpiece machining path. All the points requiring machining in the simulation image model are based on the workpiece coordinate system.

[0209] Step S702: Select multiple virtual feature points and obtain the virtual feature point location information of each virtual feature point.

[0210] Step S703: Obtain the flange pose of multiple physical feature points.

[0211] Steps S702 and S703 described above can be the same as steps S302 and S303 described above, and can both be achieved through... Figure 5c The point migration calculation interface shown is obtained.

[0212] Additionally, in step S703, the offline simulation software can obtain the current pose of the robotic arm flange in real time (based on the base coordinate system of the industrial robot in the real environment) by calling the general SDK (Software Development Kit) interface. The user needs to operate the robotic arm to precisely align the tool tip installed at the end of the robotic arm flange with the same feature point of the target workpiece model imported into the offline simulation software (where the target workpiece in the real environment and the target workpiece model in the offline simulation software have completely identical structures). Specifically, as follows... Figure 5d As shown.

[0213] Step S704: Calculate calibration data.

[0214] This step is the same as the one mentioned above. Figure 3 The process is the same as step S304, mainly involving iterative optimization calculations to solve for the first target pose information of the workpiece coordinate system in the base coordinate system. And the cutting-edge TCP currently in use, namely Offline simulation software can also obtain the robot's pose in the world coordinate system in real time by calling the general SDK interface. The first target pose information is then converted into the second target pose information of the workpiece coordinate system in the world coordinate system. Specifically, the coordinates of virtual feature points extracted from offline simulation software and the flange pose of physical feature points collected in the real environment can be used as inputs to call the aforementioned multi-point mapping iterative optimization algorithm for calculation. This algorithm, through coordinate transformation and optimization, derives the precise parameters of the tool in the real environment (such as the tool center point TCP) and the workpiece coordinate system transformation relationship. The calculation results will be directly displayed in the base coordinate system or world coordinate system, and a visual preview will be provided so that users can verify the correctness of the data.

[0215] Step S705: Synchronize the calibration data to the real system.

[0216] This step can be done Figures 5c to 5d The data synchronization button in the point migration calculation interface, as shown, allows for one-click synchronization of calibration data into the control system of the industrial robot in the real environment. This step ensures that the calibration results obtained from the offline simulation software are seamlessly applied to the actual robotic arm operation, effectively reducing on-site debugging time and improving the overall accuracy and efficiency of the operation. Through the above steps, users can efficiently complete the migration calibration from the virtual to the real environment, combining ease of operation with reliable results.

[0217] In step S706, the controller controls the industrial robot to process the target workpiece according to the processing path and control instructions received in the robot engineering.

[0218] like Figure 9 As shown, Figure 9 for Figure 7 As shown in the diagram, the offline simulation software displays the interface diagram of workpiece processing. Taking the processing operation of deburring the contour of the washbasin as an example, the grinding tool at the end of the robotic arm deburrs the contour of the washbasin along the processing path.

[0219] The following is an example illustrating the on-site implementation process of deburring the contours of toiletries. The on-site implementation steps include:

[0220] Step 1: Install the pointed tool at the end of the physical robotic arm. In this embodiment, the processing tool for deburring the contours of the toiletries already has a pointed tip, so it is not necessary to install a needle tip on the processing tool.

[0221] Step 2: Find 5 distinctive features on the toiletries.

[0222] Step 3: Use a pointed tool to touch the 5 feature points of the washing utensils in sequence. Switch the robotic arm to tool0 (i.e., the default flange coordinate system of the industrial robot). Then, record the flange posture at each touch, as shown in Table 1.

[0223] Table 1

[0224]

[0225] Step 4: After importing the product model using offline simulation software, pick virtual feature points. The virtual feature point data is shown in Table 2.

[0226] Table 2

[0227]

[0228] Step 5: Follow the specific application instructions of the offline simulation software (e.g., the user operates through...). Figure 5c The calibration results of the workpiece coordinate system and tool data are obtained by performing calculations on the point migration calculation interface shown in Table 3.

[0229] Table 3

[0230]

[0231] Step 6: Calculate the error value and average error value of the five feature points. The error value refers to the positional distance (Euclidean distance) between the virtual feature point and the physical feature point in the robot's base coordinate system, as shown in Tables 4 and 5.

[0232] Table 4

[0233]

[0234] Table 5

[0235]

[0236] The error values ​​and average error values ​​of the five feature points calculated in this embodiment can be used after obtaining the calibration results of the workpiece coordinate system and tool data. Figure 5c The point migration calculation interface is displayed as a pop-up window, allowing users to determine whether the error meets the preset requirements. This allows users to select more virtual feature points and their corresponding physical feature points to re-perform the workpiece coordinate system calibration if the requirements are not met.

[0237] Step 7: The offline simulation software determines the processing path and sends the processing path, the calibration results of the workpiece coordinate system, the position calibration results of the tip tool, and the control commands to the industrial robot, so that the industrial robot processes the target workpiece according to the processing path, the calibration results of the workpiece coordinate system, and the calibration results of the tip tool. In this embodiment, the burrs around the contour of the washbasin are polished.

[0238] In this embodiment, by employing the aforementioned workpiece coordinate system calibration method, the calibration results of the workpiece coordinate system and the tip tool are obtained. This ensures that the positions of virtual feature points in the base coordinate system are the same as those of physical feature points in the base coordinate system, or that the poses of virtual feature points in the world coordinate system are the same as those of physical feature points in the world coordinate system. Therefore, this guarantees that the industrial robot can accurately execute machining operations on the target workpiece according to the machining path generated by the offline simulation software, thereby ensuring the machining quality of the target workpiece. This solves the technical challenge of accurately executing offline simulation paths on the actual workpiece.

[0239] The above embodiment takes the grinding task as an example of the processing technology. In practical applications, offline simulation software can control a variety of tasks, such as welding tasks, the only difference being the processing technology.

[0240] Corresponding to the workpiece coordinate system calibration method described above, this application also provides a workpiece coordinate system calibration device for an industrial robot, such as... Figure 10 As shown, Figure 10 This is a schematic diagram of the structure of a workpiece coordinate system calibration device for an industrial robot provided in an embodiment of this application; the workpiece coordinate system calibration device includes:

[0241] The first acquisition module 1001 is used to acquire a simulation image model of the target workpiece; the coordinate system in which the simulation image model is located is the workpiece coordinate system;

[0242] The second acquisition module 1002 is used to acquire multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system, wherein the number of virtual feature points is ≥3; each virtual feature point corresponds one-to-one with a physical feature point selected by the user on the target workpiece.

[0243] The third acquisition module 1003 is used to acquire multiple flange pose information of the robotic arm flange of the industrial robot. The multiple flange pose information is the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool connected to the robotic arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point. The pose information includes: position information and attitude information.

[0244] The solution module 1004 is used to perform iterative optimization calculations based on the position of the virtual feature point in the base coordinate system being the same as the position of its corresponding physical feature point in the base coordinate system, with the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, and based on the positional relationship between the robotic arm flange and the tip tool, to solve for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool, which serves as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

[0245] In some embodiments, the workpiece coordinate system calibration device may further include: a synchronization module;

[0246] The synchronization module is used to synchronize the first calibration result of the workpiece coordinate system and the calibration result of the tip tool to the controller of the industrial robot; or, based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, calculate the second target pose information of the workpiece coordinate system in the world coordinate system, and use it as the calibration result, i.e. the final application result, and synchronize the final application result to the controller of the industrial robot.

[0247] This application also provides an electronic device, such as... Figure 11 As shown, Figure 11 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device includes:

[0248] Memory 1101 is used to store computer programs;

[0249] When processor 1102 executes a program stored in memory, it performs the following steps:

[0250] A simulation image model of the target workpiece is obtained; the coordinate system of the simulation image model is the workpiece coordinate system.

[0251] Obtain multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system, wherein the number of feature points is ≥3; each virtual feature point corresponds to a physical feature point selected by the user on the target workpiece.

[0252] The robot arm flange of the industrial robot is obtained with multiple flange pose information. The multiple flange pose information is the pose information of the robot arm flange in the industrial robot base coordinate system when the tip tool connected to the robot arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point. The pose information includes: position information and attitude information.

[0253] The optimization objective is to make the poses of virtual feature points in the robot base coordinate system the same as the positions of physical feature points in the robot base coordinate system. Using the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, iterative optimization calculations are performed based on the positional relationship between the robotic arm flanges and the tip tool. The optimal solutions for the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool are obtained and used as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

[0254] In some embodiments, the second target pose information of the workpiece coordinate system in the world coordinate system can be calculated based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, and used as the second calibration result.

[0255] In addition, the above-mentioned electronic device may also include a communication bus and / or a communication interface, and the processor 1202, the communication interface, and the memory 1201 communicate with each other through the communication bus.

[0256] The communication bus mentioned in the host computer diagram above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0257] The communication interface is used for communication between the host computer and other devices.

[0258] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0259] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0260] The electronic device provided in this application embodiment can be a host computer for an industrial robot or a teach pendant.

[0261] In another embodiment provided in this application, a computer-readable storage medium is also provided, which stores a computer program that, when executed by a processor, implements the steps of the workpiece coordinate system calibration method for any of the above-described industrial robots.

[0262] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to perform the steps of the workpiece coordinate system calibration method for any of the industrial robots described in the above embodiments.

[0263] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a solid-state drive (SSD), etc.

[0264] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0265] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0266] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A method for calibrating the workpiece coordinate system of an industrial robot, characterized in that, include: A simulation image model of the target workpiece is obtained; the coordinate system of the simulation image model is the workpiece coordinate system. Obtain multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system; the number of virtual feature points is ≥3; each virtual feature point corresponds one-to-one with a physical feature point selected by the user on the target workpiece. Obtain multiple flange pose information of the robotic arm flange of the industrial robot; the multiple flange pose information is the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool connected to the robotic arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point. The pose information includes: position information and attitude information; With the goal of ensuring that the positions of virtual feature points in the base coordinate system are the same as the positions of their corresponding physical feature points in the base coordinate system, and using the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, iterative optimization calculations are performed based on the positional relationship between the robotic arm flange and the tip tool to solve for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool. This solution serves as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

2. The workpiece coordinate system calibration method according to claim 1, characterized in that, Also includes: First synchronization process: Synchronize the first calibration result of the workpiece coordinate system to the controller of the industrial robot; Alternatively, based on the known pose information of the robot's base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, the second target pose information of the workpiece coordinate system in the world coordinate system is calculated as the second calibration result. The second calibration result is then synchronized to the controller of the industrial robot, so that the controller controls the industrial robot based on the first calibration result or the second calibration result. or, The second synchronization process involves synchronizing the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool to the controller of the industrial robot; or, based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system, calculating the second target pose information of the workpiece coordinate system in the world coordinate system as the second calibration result, and synchronizing the second calibration result and the position calibration result of the tip tool to the controller of the industrial robot. This enables the controller to control the industrial robot based on the first calibration result or the second calibration result, and to verify the cutting-edge tool based on the position calibration result.

3. The workpiece coordinate system calibration method according to claim 2, characterized in that, The optimal solution for solving the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool specifically includes: Substitute the initial values ​​of the set workpiece coordinate system and the tip tool position, along with the known parameters, into the preset residual calculation function to calculate the initial function value of the residual calculation function; the residual calculation function is used to calculate the error value between the position of the virtual feature point in the base coordinate system and the position of its corresponding physical feature point in the base coordinate system. With the goal of making the residual calculation function equal to 0, the optimal solution for the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool is obtained by using the Jacobian matrix constructed based on the residual calculation function and a preset iterative algorithm for iterative calculation.

4. The workpiece coordinate system calibration method according to claim 3, characterized in that, The residual calculation function and Jacobian matrix mentioned above are derived in advance according to the following steps: Define the homogeneous pose matrix formulas for the workpiece coordinate system under the robot base coordinate system, the homogeneous pose matrix formulas for the flange of the robot arm under the robot base coordinate system, the homogeneous pose matrix formulas for the tool at the end of the flange under the flange coordinate system, and the homogeneous pose matrix formulas for the points under the workpiece coordinate system. With the optimization objective of having the position of the virtual feature point in the base coordinate system the same as the position of its corresponding physical feature point in the base coordinate system, the residual calculation function and the solution formula of the residual calculation function are defined using the defined formulas of each pose homogeneous matrix. The formula for solving the residual function includes: the formula for the first target pose information of the workpiece coordinate system in the base coordinate system and the formula for the position information of the tip tool; The Jacobian matrix is ​​constructed based on the solution formula of the residual calculation function.

5. The workpiece coordinate system calibration method according to claim 4, characterized in that, The residual calculation function is: ； ； The Jacobian matrix is: ； in, ； To perform antisymmetric matrix operations on three-dimensional vectors; in, Let be the position coordinates of the flange corresponding to a certain physical feature point i in the robot's base coordinate system r. This refers to the attitude information of the robotic arm flange corresponding to the physical feature point i in the robot's base coordinate system r. These are the position coordinates of the tool in the flange coordinate system. Let be the position coordinates of the workpiece coordinate system u in the base coordinate system r. The orientation information of the origin of the workpiece coordinate system u in the robot base coordinate system r; Let i be the position coordinates of a virtual feature point i in the workpiece coordinate system u; i represents the feature point number. The residual calculation function and Jacobian matrix mentioned above are derived in advance according to the following steps: Define the pose information for each coordinate system, including: The pose homogeneous matrix of the workpiece coordinate system u in the robot base coordinate system r is denoted as... ; The homogeneous matrix of the flange pose of the robotic arm in the robot's base coordinate system r is denoted as: ; The homogeneous pose matrix of the tool at the flange end in the flange coordinate system is denoted as: ; The homogeneous pose matrix of a point in the workpiece coordinate system u is denoted as: ; in, ; Therefore, we can conclude that: ； The optimization problem formula is established with the goal of minimizing the pose error between each virtual feature point in the robot base coordinate system u and the position error between each physical feature point in the robot base coordinate system u. =0； Based on the optimization problem formula, the residual calculation function is defined, and the Jacobian matrix is ​​constructed based on the residual calculation function.

6. The workpiece coordinate system calibration method according to claim 4, characterized in that, For situations where the second calibration results need to be synchronized to the controller of the industrial robot, the following are also included: The pose homogeneity matrix formulas for the robot base coordinate system in the world coordinate system, the pose homogeneity matrix formulas for the first target pose information, and the pose homogeneity matrix formulas for the second target pose information are predefined. Based on the pose homogeneous matrix formula of the known pose information and the pose homogeneous matrix formula of the first target pose information, as well as the transformation relationship between the known pose information and the first target pose information, the position calculation formula and attitude calculation formula in the second target pose information are derived in advance. The step of calculating the second target pose information of the workpiece coordinate system in the world coordinate system based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system includes: calculating the second target pose information based on the known pose information and the first target pose information, using the position calculation formula and the attitude calculation formula.

7. The workpiece coordinate system calibration method according to claim 6, characterized in that, The pose homogeneous matrix of the robot's base coordinate system in the world coordinate system, based on the known pose information, is denoted as: ; The calculated homogeneous pose matrix of the first target pose information in the base coordinate system of the workpiece coordinate system is denoted as... ; The homogeneous pose matrix of the second target pose information in the world coordinate system of the workpiece coordinate system is denoted as follows: ; The step of calculating the second target pose information of the workpiece coordinate system in the world coordinate system based on the known pose information of the robot base coordinate system in the world coordinate system and the calculated first target pose information of the workpiece coordinate system in the base coordinate system includes: The pose information of the second target is calculated using the following formula: ； ； ； in, Let r be the position coordinates of the origin of the robot's base coordinate system r in the world coordinate system w. This represents the attitude information of the robot's base coordinate system origin r in the world coordinate system w. Let w be the position coordinates of the origin of the workpiece coordinate system u in the world coordinate system w. This refers to the attitude information of the origin of the workpiece coordinate system u in the world coordinate system w. Let be the position coordinates of the workpiece coordinate system u in the base coordinate system r. This represents the orientation information of the origin of the workpiece coordinate system u in the robot base coordinate system r.

8. The workpiece coordinate system calibration method according to claim 2, characterized in that, During the extraction of virtual feature points, a virtual feature point identifier is set for each virtual feature point, and a corresponding physical feature point identifier is set for each physical feature point. After obtaining multiple virtual feature points extracted from the simulation image model and their position information in the workpiece coordinate system, the position information of each virtual feature point is saved using the virtual feature point identifier as an index. After obtaining multiple flange pose information of the robotic arm flange of the industrial robot, the flange pose information corresponding to each physical feature point is saved using the physical feature point identifier as an index. Before solving for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool, the method further includes: Display the feature point migration calculation interface; Based on the virtual feature point identifier or physical feature point identifier selected by the user on the feature point migration calculation interface, the corresponding virtual feature point position information or flange pose information is retrieved from the saved virtual feature point position information or flange pose information and displayed. After the calculation button on the feature point migration calculation interface is triggered, the step of solving the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool is executed, and the calculated optimal solution of the first target pose information and the position information of the tip tool is displayed. When the data synchronization button set on the feature point migration calculation interface is triggered, the first synchronization process or the second synchronization process is executed.

9. The workpiece coordinate system calibration method according to claim 8, characterized in that, After completing the step of finding the optimal solution for the first target pose information and the position information of the tip tool in the base coordinate system of the workpiece coordinate system, the optimal solution for the first target pose information and the position information of the tip tool is further substituted into a preset residual calculation function for calculation to obtain the error information of each virtual feature point and its corresponding physical feature point and display it so that the user can judge whether the error meets the preset requirements based on the error information. If the requirements are not met, more virtual feature points and corresponding physical feature points can be selected to re-perform the workpiece coordinate system calibration.

10. The workpiece coordinate system calibration method according to claim 1, characterized in that, The tip tool connected to the robotic arm flange is: a machining tool with a pointed tip used to process the target workpiece; or, A calibration tool with a pointed tip, installed at the end of a machining tool for calibration; the calibration tool is removed after the workpiece coordinate system calibration is completed.

11. A workpiece coordinate system calibration device for an industrial robot, characterized in that, include: The first acquisition module is used to acquire a simulation image model of the target workpiece; the coordinate system in which the simulation image model is located is the workpiece coordinate system; The second acquisition module is used to acquire multiple virtual feature points extracted from the simulation image model and their virtual feature point position information in the workpiece coordinate system. The number of virtual feature points is ≥3. Each virtual feature point corresponds one-to-one with a physical feature point position selected by the user on the target workpiece. The third acquisition module is used to acquire multiple flange pose information of the robotic arm flange of the industrial robot. The multiple flange pose information is the pose information of the robotic arm flange in the industrial robot base coordinate system when the tip tool connected to the robotic arm flange is sequentially aligned with the physical feature points corresponding to each virtual feature point. The pose information includes: position information and attitude information; The solution module is used to optimize the workpiece coordinate system by taking the position of the virtual feature point in the base coordinate system as the same as the position of its corresponding physical feature point in the base coordinate system. Using the position information of the multiple virtual feature points and the pose information of the multiple flanges as known parameters, it performs iterative optimization calculations based on the positional relationship between the robotic arm flange and the tip tool to solve for the optimal solution of the first target pose information of the workpiece coordinate system in the base coordinate system and the position information of the tip tool. This solution serves as the first calibration result of the workpiece coordinate system and the position calibration result of the tip tool.

12. An electronic device, characterized in that, include: Memory, used to store computer programs; The processor, when executing a program stored in memory, implements the workpiece coordinate system calibration method for the industrial robot according to any one of claims 1-10.

13. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the workpiece coordinate system calibration method for the industrial robot according to any one of claims 1-10.

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