A robot line laser calibration method, device and storage medium

Abstract

The present invention discloses a robot line laser calibration method, device, and storage medium. The method includes: constructing a tool end coordinate transformation matrix based on the robot tool end; after placing a measurement standard block at a preset measurement position, performing scanning processing to obtain point cloud data, robot end posture, scanning start point, and scanning end point; extracting feature measurement position points from the point cloud data; performing tool posture extraction processing based on target feature points to obtain tool end posture; calculating robot position transformation points based on the robot end posture, feature measurement position points, scanning start point, and scanning end point; calculating tool end position transformation points; constructing an objective function based on the robot position transformation points and the tool end position transformation points; and optimizing the objective function using a preset nonlinear optimization method to obtain a target calibration value. The present invention realizes line laser calibration and improves accuracy and efficiency. The present invention can be widely applied to the field of line laser calibration technology.

Description

Technical Field

[0001] The present invention relates to the technical field of line laser calibration, and in particular to a robot line laser calibration method, device and storage medium. Background Art

[0002] Online laser scanning technology is an advanced measurement and inspection tool that scans the surface of an object by emitting a thin laser line to obtain high-precision three-dimensional data. Line laser hand-eye calibration is a key step in the robot vision system, which requires precise alignment of the coordinate system of the laser scanner (hand) and the robot camera (eye). When fitting a circle or ellipse, the traditional line laser calibration method can only scan one-sixth of the arc length of the entire circle or ellipse; when fitting the axis of a cylinder or the center of a sphere, the distance to the origin of the laser coordinate system is close, resulting in large fitting errors and low accuracy. At the same time, the traditional method only calibrates the conversion relationship between the laser and the end of the robot, and the robot tool parameters need to be calibrated later. The operation is complicated, time-consuming, labor-intensive, and inefficient.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0004] The embodiments of the present invention provide a robot line laser calibration method, device and storage medium, which effectively improve accuracy and efficiency.

[0005] In one aspect, an embodiment of the present invention provides a robot line laser calibration method, comprising the following steps:

[0006] According to the robot tool end, construct the tool end coordinate transformation matrix;

[0007] After the measurement standard block is placed at a preset measurement position, scanning processing is performed to obtain point cloud data, robot end position, scanning start point and scanning end point. The measurement standard block has target feature points, and the target feature points include convex feature points or concave feature points.

[0008] Extracting feature measurement location points from the point cloud data;

[0009] Performing tool pose extraction processing based on the target feature points to obtain the tool end pose;

[0010] Calculating a robot position transformation point according to the robot end position, the feature measurement position point, the scanning start point, and the scanning end point;

[0011] Calculating a tool end position transformation point according to an initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end posture, and the tool end posture;

[0012] Constructing an objective function according to the robot position change point and the tool end position change point, wherein the optimization goal of the objective function is to minimize the objective function value;

[0013] The objective function is optimized using a preset nonlinear optimization method to obtain a target calibration value, which is used as a line laser calibration result. The target calibration value includes a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value.

[0014] In some embodiments, constructing a tool end coordinate transformation matrix according to the robot tool end includes:

[0015] Performing a rough calibration process on the robot tool end using a preset robot tool coordinate system calibration method to obtain an initial tool coordinate transformation matrix;

[0016] The tool end coordinate transformation matrix is ​​calculated based on the initial tool coordinate transformation matrix.

[0017] In some embodiments, after the measurement standard block is placed at a preset measurement position, scanning processing is performed to obtain point cloud data, robot end position, scanning start point and scanning end point, including:

[0018] After the measurement standard block is placed at a preset measurement position, a posture adjustment signal is generated, wherein the posture adjustment signal is used to control the robot to adjust to a preset measurement posture so that the laser scanning can detect the plurality of target feature points in the measurement standard block;

[0019] Under the preset measurement posture, a scanning signal is generated, and the scanning signal is used to control the laser scanning device to scan the measurement standard block to obtain the point cloud data, the robot end position, the scanning start point and the scanning end point.

[0020] In some embodiments, performing tool pose extraction processing based on the target feature points to obtain the tool end pose includes:

[0021] Under the preset measurement posture, a tool end movement signal is generated, and the tool end movement signal is used to control the robot tool end to move to the position of the target feature point to obtain the tool end posture.

[0022] In some embodiments, the calculating of the robot position transformation point according to the robot end position, the feature measurement position point, the scanning start point, and the scanning end point includes:

[0023] Calculate the line laser coordinate transformation matrix according to the initial line laser transformation offset value and the initial line laser Euler rotation angle value;

[0024] Calculating a scanning direction according to the robot end position, the line laser coordinate conversion matrix, the scanning start point and the scanning end point;

[0025] Performing plane projection processing on the scanning direction to obtain an x-axis projection direction and a z-axis projection direction;

[0026] Calculating a first angle according to the x-axis projection direction and the y-axis of the robot end coordinate system;

[0027] Calculating a second angle according to the z-axis projection direction and the y-axis of the robot end coordinate system;

[0028] Calculating a feature position transformation point based on the first angle, the second angle, an x-axis component of the feature position transformation point, a z-axis component of the feature position transformation point, and the feature measurement position point;

[0029] The robot position transformation point is calculated according to the characteristic position transformation point, the line laser coordinate conversion matrix and the robot end posture.

[0030] In some embodiments, constructing an objective function based on the robot position transformation point and the tool end position transformation point includes:

[0031] Performing a first measurement process based on the robot position transformation point and the tool end position transformation point to obtain a first robot transformation point and a first tool transformation point;

[0032] performing a second measurement process based on the robot position transformation point and the tool end position transformation point to obtain a second robot transformation point and a second tool transformation point, wherein a measurement posture of the second measurement process is different from a measurement posture of the first measurement process, and a placement position of the measurement standard block in the second measurement process is the same as the placement position of the measurement standard block in the first measurement process;

[0033] performing a third measurement process based on the robot position transformation point and the tool end position transformation point to obtain a third robot transformation point and a third tool transformation point, wherein a measurement posture of the third measurement process is different from a measurement posture of the second measurement process, and a placement position of the measurement standard block in the third measurement process is the same as a placement position of the measurement standard block in the second measurement process;

[0034] calculating a total position point distance based on the first robot transformation point, the first tool transformation point, the second robot transformation point, the second tool transformation point, the third robot transformation point, and the third tool transformation point;

[0035] Calculating a distance between a first tool position point and a second tool position point according to the first tool transformation point and the second tool transformation point;

[0036] Calculating a distance between the second tool position points according to the second tool transformation point and the third tool transformation point;

[0037] Calculating a distance between a third tool position point and the first tool transformation point and the third tool transformation point;

[0038] The objective function is constructed based on the total location point distance, the first tool location point distance, the second tool location point distance, and the third tool location point distance.

[0039] In some embodiments, the calculating the scanning direction according to the robot end position, the line laser coordinate transformation matrix, the scanning start point and the scanning end point includes:

[0040] The scanning direction is calculated according to the robot end position, the line laser coordinate conversion matrix, the scanning start point and the scanning end point using a scanning direction calculation formula. The scanning direction calculation formula is:

[0041]

[0042] Where, is the scanning direction, is the end position of the robot, T em is the line laser coordinate transformation matrix, is the scanning endpoint, is the scanning starting point.

[0043] On the other hand, an embodiment of the present invention provides a robot line laser calibration device, comprising:

[0044] The first module is used to construct a tool end coordinate transformation matrix according to the robot tool end;

[0045] The second module is used to scan and process the measurement standard block after it is placed at a preset measurement position to obtain point cloud data, robot end position, scanning start point and scanning end point. The measurement standard block has target feature points, and the target feature points include convex feature points or concave feature points.

[0046] A third module is used to extract feature measurement position points from the point cloud data;

[0047] The fourth module is used to perform tool posture extraction processing based on the target feature points to obtain the tool end posture;

[0048] A fifth module is used to calculate the robot position transformation point according to the robot end posture, the feature measurement position point, the scanning start point and the scanning end point;

[0049] A sixth module is used to calculate a tool end position transformation point according to an initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end posture and the tool end posture;

[0050] A seventh module is configured to construct an objective function based on the robot position change point and the tool end position change point, wherein the optimization goal of the objective function is to minimize the objective function value;

[0051] The eighth module is used to optimize the objective function using a preset nonlinear optimization method to obtain a target calibration value. The target calibration value is used as a line laser calibration result. The target calibration value includes a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value.

[0052] In another aspect, an embodiment of the present invention provides a computer device, comprising:

[0053] at least one processor;

[0054] at least one memory for storing at least one program;

[0055] When the at least one program is executed by the at least one processor, the at least one processor implements the method.

[0056] On the other hand, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0057] The beneficial effects of the present invention are as follows:

[0058] The embodiment of the present invention first constructs a tool end coordinate transformation matrix based on the robot tool end, and after the measurement standard block is placed at a preset measurement position, performs scanning processing to obtain point cloud data, robot end posture, scanning start point and scanning end point, and extracts feature measurement position points from the point cloud data. Then, based on the target feature points, tool posture extraction processing is performed to obtain the tool end posture, and then the robot position transformation point and the tool end position transformation point are calculated, and the objective function is constructed. Finally, the preset nonlinear optimization method is used to optimize the objective function to obtain the target calibration value, thereby realizing line laser calibration and improving accuracy and efficiency.

[0059] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0061] Figure 1 This is a flow chart of a robot line laser calibration method according to an embodiment of the present invention;

[0062] Figure 2 A schematic diagram of an overall process for calculating calibration parameters according to an embodiment of the present invention;

[0063] Figure 3 This is a schematic structural diagram of a robot line laser calibration device according to an embodiment of the present invention;

[0064] Figure 4 The figure is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are merely examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the appended claims.

[0066] It will be understood that the terms "first", "second", etc. used in this application may be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0067] The terms "at least one", "plurality", "each", "any", etc. used in this application include "at least one", "two" or more, "plurality" or "each", "any" or "any one", "each" or "any one" as used herein.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0069] Before explaining the embodiments of the present application in detail, some of the nouns and terms involved in the embodiments of the present application are first explained. The nouns and terms involved in the embodiments of the present application are subject to the following explanations.

[0070] Line laser hand-eye calibration is a fundamental concept in robotics and automation. It involves accurately determining the spatial relationship between a robot's end effector (hand) and its camera (eye). This is crucial for robots to perform tasks such as grasping objects, navigating environments, and interacting with humans. Line laser hand-eye calibration utilizes a line laser to establish a correspondence between the robot's hand and camera, enabling precise calibration.

[0071] In related technologies, online laser scanning technology is an advanced measurement and detection tool that scans the surface of an object by emitting a thin laser line to obtain high-precision three-dimensional data. This technology has been widely used in the field of robotic automation, especially in processes such as grinding, cutting and welding that require high precision and high efficiency. Line laser hand-eye calibration is a key step in the robot vision system. It involves accurately aligning the coordinate system of the laser scanner (hand) with the robot camera (eye) to ensure that the robot can accurately perform tasks based on visual information. This calibration process is crucial to improving the accuracy and reliability of robot operations. The disadvantages of traditional robot line laser calibration methods include: (1) It is necessary to fit a circle or ellipse, but due to the characteristics of laser scanning, it can usually only scan about one-sixth of the arc length of the entire circle or ellipse, and for laser scanners with relatively narrow line widths, there are fewer data points and the fitting error is larger. (2) For fitting the axis of a cylinder and the center of a sphere, it is necessary to avoid the ellipse or circle center being near the origin of the laser coordinate system as much as possible during scanning, otherwise the fitting error will be large; when the line laser line width is small, there are fewer measurement positions that meet the conditions. (3) The hand-eye calibration method usually only calibrates the conversion relationship between the laser and the robot end, and does not directly calibrate the conversion relationship between the laser and the robot tool. In practical applications, it is also necessary to accurately calibrate the robot tool parameters, such as cutting and other precision processes. The traditional four-point calibration method is difficult to achieve high accuracy during operation and is time-consuming and labor-intensive.

[0072] In view of this, an embodiment of the present invention proposes a robot line laser calibration method, device and storage medium. By using a measuring standard block to perform numerical conversion on the robot end coordinate system, the line laser original coordinate system and the tool end coordinate system, this embodiment can achieve line laser calibration without fitting features, thereby improving accuracy and efficiency.

[0073] A robot line laser calibration method provided in an embodiment of the present application relates to the field of line laser calibration technology. A robot line laser calibration method provided in an embodiment of the present application can be applied to a terminal, can also be applied to a server, and can also be software running in a terminal or a server. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, and a car terminal, etc., but is not limited to this; the server side can be configured as an independent physical server, or as a server cluster or distributed system composed of multiple physical servers, and can also be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network; the software can be an application that implements a robot line laser calibration method, etc., but is not limited to the above forms.

[0074] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and the like. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments in which tasks are performed by remote processing devices connected via a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media, including storage devices.

[0075] The following is a detailed explanation of the embodiments of the present application with reference to the accompanying drawings:

[0076] Figure 1 This is an optional flow chart of a robot line laser calibration method provided in an embodiment of the present application. Figure 1 The method may include but is not limited to steps S101 to S108.

[0077] Step S101: constructing a tool end coordinate transformation matrix according to the robot tool end;

[0078] Step S102: After the measurement standard block is placed at the preset measurement position, scanning processing is performed to obtain point cloud data, robot end position, scanning start point and scanning end point. The measurement standard block has target feature points, and the target feature points include convex feature points or concave feature points.

[0079] Step S103: extracting feature measurement position points from the point cloud data;

[0080] Step S104: Perform tool pose extraction processing based on the target feature points to obtain the tool end pose;

[0081] Step S105: Calculate the robot position transformation point based on the robot end position, feature measurement position point, scanning start point, and scanning end point;

[0082] Step S106, calculating the tool end position transformation point according to the initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end posture and the tool end posture;

[0083] Step S107: construct an objective function based on the robot position change point and the tool end position change point, and the optimization goal of the objective function is to minimize the objective function value;

[0084] Step S108: Optimize the objective function using a preset nonlinear optimization method to obtain a target calibration value. The target calibration value is used as the line laser calibration result. The target calibration value includes a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value.

[0085] Steps S101 to S108 shown in the embodiment of the present application implement line laser calibration, thereby improving accuracy and efficiency.

[0086] In some embodiments, in step S101, constructing a tool end coordinate transformation matrix based on the robot tool end may include but is not limited to the following steps:

[0087] The robot tool end is roughly calibrated using the preset robot tool coordinate system calibration method to obtain the initial tool coordinate transformation matrix;

[0088] According to the initial tool coordinate transformation matrix, the tool end coordinate transformation matrix is ​​calculated.

[0089] In some embodiments, before calibrating the laser scanning device, the robot tool end can be roughly calibrated using a preset robot tool coordinate system calibration method to obtain the initial tool coordinate transformation matrix T′. es, and use the initial tool coordinate transformation matrix as the initial value to calculate the tool end coordinate transformation matrix T es , to reduce the search range of nonlinear optimization. Among them, the preset robot tool coordinate system calibration method can include a four-point method. In addition to the tool end coordinate transformation matrix, this embodiment also calculates the line laser coordinate transformation matrix T em , in preparation for subsequent calibration. Among them, e represents the robot end coordinate system, m represents the line laser original coordinate system, and s represents the tool end coordinate system. em , which essentially corresponds to the offset of the m coordinate system conversion (i.e., the initial line laser conversion offset value) and the Euler rotation angle (i.e., the initial line laser Euler rotation angle value). Among them, the initial line laser conversion offset value can include x m 、y m 、z m , the initial line laser Euler rotation angle value can include ex m 、ey m ,ez m (in the order of ZYX); for T es , then only the offset (ie, the initial tool end conversion offset value) is required, wherein the initial tool end conversion offset value may include x s 、y s 、z s , so there are a total of 9 parameter values ​​that need to be calibrated. Since the posture of the tool end coordinate system does not affect T es , so the Euler rotation angles of the s-coordinate system can all be set to 0. It can be understood that the values ​​of the above 9 parameters that need to be calibrated only affect the possibility of the nonlinear fitting falling into the local minimum. The usual practice is to take arbitrary values ​​and then adjust them according to the fitting results, or use other methods.

[0090] In some embodiments, in step S102, after the measurement standard block is placed at the preset measurement position, scanning processing is performed to obtain point cloud data, robot end position, scanning start point and scanning end point, which may include but is not limited to the following steps:

[0091] After the measurement standard block is placed at the preset measurement position, a posture adjustment signal is generated, which is used to control the robot to adjust to the preset measurement posture so that the laser scanning can detect several target feature points in the measurement standard block;

[0092] Under the preset measurement posture, a scanning signal is generated. The scanning signal is used to control the laser scanning device to scan the measurement standard block to obtain point cloud data, robot end position, scanning start point and scanning end point.

[0093] In some embodiments, a measurement standard block can be placed first, wherein the measurement standard block needs to have several target feature points that are easy to select. The specific shape is not limited, and can include relatively obvious raised feature points or recessed feature points. The measurement standard block is placed in the operating space accessible to the robot and maintains its position unchanged in subsequent multiple measurements. After the measurement standard block is placed at the preset measurement position, a posture adjustment signal is generated. The posture adjustment signal can be used to control the robot to adjust to a preset measurement posture, so that the laser scanning can detect several target feature points in the measurement standard block. Then, a scanning signal is generated under the preset measurement posture. The scanning signal can be used to control the laser scanning device to scan the measurement standard block to obtain point cloud data and the robot end posture corresponding to the scanning origin. Scan starting point and scan endpoint The laser scanning device may include a laser scanner. i represents the i-th scan.

[0094] In some embodiments, in step S103, feature measurement position points may be extracted from the point cloud data. For example, corresponding position points of each target feature point measured by a laser scanner may be extracted from the point cloud data as feature measurement position points.

[0095] In some embodiments, in step S104, tool pose extraction is performed based on the target feature points to obtain the tool end pose, which may include but is not limited to the following steps:

[0096] Under the preset measurement posture, a tool end movement signal is generated. The tool end movement signal is used to control the robot tool end to move to the position of the target feature point to obtain the tool end posture.

[0097] In some embodiments, the robot's scanning posture can be kept unchanged under the preset measurement posture to generate a tool end movement signal. The tool end movement signal can be used to control the robot's tool end to move to the position of the target feature point of the measurement standard block according to the corresponding point position to obtain the tool end posture.

[0098] In some embodiments, in step S105, the robot position transformation point is calculated based on the robot end position, feature measurement position point, scanning start point, and scanning end point, which may include but is not limited to the following steps:

[0099] Calculate the line laser coordinate transformation matrix according to the initial line laser transformation offset value and the initial line laser Euler rotation angle value;

[0100] Calculate the scanning direction based on the robot end position, line laser coordinate transformation matrix, scanning start point and scanning end point;

[0101] Perform plane projection processing on the scanning direction to obtain the x-axis projection direction and the z-axis projection direction;

[0102] Calculate the first angle based on the x-axis projection direction and the y-axis of the robot end coordinate system;

[0103] Calculate the second angle based on the z-axis projection direction and the y-axis of the robot end coordinate system;

[0104] Calculate the feature position transformation point according to the first included angle, the second included angle, the x-axis component of the feature position transformation point, the z-axis component of the feature position transformation point, and the feature measurement position point;

[0105] The robot position transformation point is calculated based on the feature position transformation point, the line laser coordinate transformation matrix and the robot end pose.

[0106] In some embodiments, it is assumed that the laser is scanned along the Y-axis of its original laser coordinate system. Because the measurement coordinate system of the laser scanner is different from its original coordinate system, the measurement coordinate system is affected by the scanning direction and uses the direction of its scanning motion as the measurement Y-axis. There is an angle with the Y-axis of the original coordinate system. Therefore, it is necessary to compensate for this angle and transform the measured coordinate value into the original laser coordinate system of the laser scanner. The line laser coordinate transformation matrix T can be calculated based on the initial line laser conversion offset value and the initial line laser Euler rotation angle value. em Then, the scanning direction is calculated according to the robot end position, the line laser coordinate transformation matrix, the scanning start point and the scanning end point using the scanning direction calculation formula. The scanning direction calculation formula is: Where, is the scanning direction, is the robot end position, T em is the line laser coordinate transformation matrix, is the scan end point, The line laser coordinate conversion matrix is ​​an iterative calculation. When setting the initial line laser conversion offset value (3 values ​​to be calculated [x m ,y m ,z m ]) and the initial line laser Euler rotation angle value (3 values ​​to be calculated [ex m ,ey m ,ez m ]) can be iterated. Then perform plane projection processing on the scanning direction to obtain the x-axis projection direction and the z-axis projection direction It is understandable that Is the scanning direction Projection on the YZ plane, Is the scanning direction Projection on the XY plane. Then calculate the first angle θ based on the x-axis projection direction and the y-axis of the robot end coordinate system x , and calculate the second angle θ based on the z-axis projection direction and the y-axis of the robot end coordinate system z Then, according to the first angle, the second angle, the x-axis component of the feature position transformation point, the z-axis component of the feature position transformation point and the feature measurement position

[0107] Set points and calculate feature position transformation points. Among them, calculate feature measurement position points The transformation from the measurement coordinate system to the laser original coordinate system (i.e., the feature position transformation point) can include the following calculation formula: Where, is the feature position transformation point, is the feature measurement location point, for The x-axis component of for The y-axis component of for The z-axis component of the feature position transformation point can be calculated by combining the above formulas. Finally, according to the feature position transformation point, the line laser coordinate transformation matrix and the robot end posture, the feature position transformation point in the laser original coordinate system is converted to Convert to the robot coordinate system and calculate the robot position transformation point. The calculation formula of the robot position transformation point is: Where, is the robot position change point, is the robot end position, T em is the line laser coordinate transformation matrix, is the feature position transformation point.

[0108] In some embodiments, in step S106, the tool end position transformation point can be calculated based on the initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end position and the tool end position. The calculation formula of the tool end position transformation point is: Where, is the tool end position transformation point, is the robot end position, T es is the tool end coordinate transformation matrix, [0] represents the origin of the tool coordinate system. Among them, after setting the initial tool end transformation offset value (3 pending values ​​[x s ,y s ,z s ]), calculate the tool end coordinate transformation matrix T es It can be understood that the tool end coordinate transformation matrix T esIt is the value that needs to be found by iterative calculation. The value of is the tool end pose The XYZ offset value in .

[0109] In some embodiments, in step S107, constructing an objective function based on the robot position transformation point and the tool end position transformation point may include but is not limited to the following steps:

[0110] Performing a first measurement process based on the robot position transformation point and the tool end position transformation point to obtain a first robot transformation point and a first tool transformation point;

[0111] performing a second measurement process based on the robot position transformation point and the tool end position transformation point to obtain a second robot transformation point and a second tool transformation point, wherein a measurement posture of the second measurement process is different from the measurement posture of the first measurement process, and a placement position of the measurement standard block in the second measurement process is the same as the placement position of the measurement standard block in the first measurement process;

[0112] performing a third measurement process based on the robot position transformation point and the tool end position transformation point to obtain a third robot transformation point and a third tool transformation point, wherein a measurement posture of the third measurement process is different from the measurement posture of the second measurement process, and a placement position of the measurement standard block in the third measurement process is the same as the placement position of the measurement standard block in the second measurement process;

[0113] calculating a total position point distance based on the first robot transformation point, the first tool transformation point, the second robot transformation point, the second tool transformation point, the third robot transformation point, and the third tool transformation point;

[0114] Calculate the distance between the first tool position point and the second tool transformation point;

[0115] Calculating the distance between the second tool position points according to the second tool transformation point and the third tool transformation point;

[0116] Calculating a distance between a third tool position point and a first tool transformation point according to the first tool transformation point and the third tool transformation point;

[0117] An objective function is constructed based on the total location point distance, the first tool location point distance, the second tool location point distance, and the third tool location point distance.

[0118] In some embodiments, steps S102 to S106 can be repeatedly performed to obtain different robot position transformation points and tool end position transformation points. Exemplarily, three measurements can be repeated, namely the first measurement process, the second measurement process and the third measurement process. According to the calculation steps of the robot position transformation point and the tool end position transformation point, when the first measurement process is performed, the first robot transformation point and the first tool transformation point are obtained; when the second measurement process is performed, the second robot transformation point and the second tool transformation point are obtained; when the third measurement process is performed, the third robot transformation point and the third tool transformation point are obtained. Among them, the measurement posture of the second measurement process is different from the measurement posture of the first measurement process, and the measurement posture of the third measurement process is different from the measurement posture of the second measurement process, that is, a different measurement posture is used for each measurement. The placement position of the measurement standard block in the second measurement process is the same as the placement position of the measurement standard block in the first measurement process, and the placement position of the measurement standard block in the third measurement process is the same as the placement position of the measurement standard block in the second measurement process, that is, the placement position of the measurement standard block is kept unchanged in multiple measurements. It can be understood that since the measurement standard block is stationary in the robot coordinate system, therefore, That is, the spatial coordinates of the feature point (i.e., the robot position transformation point) obtained by laser measurement and the actual point of the tool to the feature point (i.e., the tool end position transformation point) should be equal. The tool end position change point between the three measurements should be the same. Then, the total position point distance is calculated based on the first robot change point, the first tool change point, the second robot change point, the second tool change point, the third robot change point and the third tool change point. The calculation formula for the total position point distance is: D1 = ∑ j norm( b p sj - b p mj ), where D1 is the total distance between locations, norm(.) is the distance calculation function, b p sj is the tool end position transformation point of the jth target feature point, b p mj is the robot position transformation point of the jth target feature point, and j is the count value of the feature point. Then, based on the first tool transformation point and the second tool transformation point, the distance between the first tool position point and the first tool position point is calculated. The calculation formula for the distance between the first tool position point and the first tool position point is: Where D 12 is the distance to the first tool position point, is the first tool transformation point, The second tool transformation point is the second tool transformation point. The distance between the second tool position point and the third tool transformation point is calculated according to the second tool transformation point and the third tool transformation point. The calculation formula for the distance between the second tool position point is: Where D 12 is the distance to the second tool position point, is the second tool transformation point, The third tool transformation point is calculated based on the first tool transformation point and the third tool transformation point. The calculation formula of the third tool position point distance is: Where D 13 is the distance to the third tool position point, is the first tool transformation point, is the third tool transformation point. Finally, the objective function is constructed based on the total position point distance, the first tool position point distance, the second tool position point distance and the third tool position point distance, where the objective function expression is: D = D1 + D 12 +D 13 +D 23 , where D is the objective function value. The optimization goal of the objective function is to minimize the objective function value.

[0119] In some embodiments, in step S108, the objective function may be optimized using a preset nonlinear optimization method to obtain a target calibration value. The target calibration value is used as a line laser calibration result. The target calibration value may include a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value. The preset nonlinear optimization method may include a nonlinear least squares method or a particle swarm method. For example, the objective function may be optimized using a nonlinear least squares method to obtain a target line laser conversion offset value (x′ m , y′ m 、z′ m ), target line laser Euler rotation angle value (ex′ m ey′ m ,ez′ m ) and the target tool end translation offset value (x′ s , y′ s 、z′ s ), as the line laser calibration result.

[0120] In some embodiments, the overall process of calculating the calibration parameters is as follows: Figure 2 As shown in the figure, the four-point calibration method can be used to roughly calibrate the end of the robot tool. After placing the measurement standard block, the calibration parameters are defined and scanned to obtain calibration data. Then, the laser scanning data is corrected, and a fitting model for the laser coordinate system transformation is established. The objective function to be optimized is constructed, and finally, the nonlinear optimization method is used to optimize the objective function to obtain the corresponding calibration parameters.

[0121] In some embodiments, this embodiment constructs an optimization problem model (objective function) and optimizes the objective function to calculate the conversion relationship between the laser and the robot end, and at the same time corrects the conversion relationship between the tool and the robot end, thereby improving the calibration accuracy. This embodiment uses the construction of a calibration scene and data collection as the premise and basis for subsequent algorithms. In addition, in the hand-eye standard method for cylinders or spheres, the actual cylinder calibration method is affected by the acquisition position, and the fitted cylinder axis is very discrete. However, the method of this embodiment does not need to fit circles and ellipses, nor does it need to calculate the center of the circle, thus avoiding fitting errors introduced by data problems. At the same time, the method of this embodiment also optimizes the conversion relationship between the tool and the robot end obtained by the four-point calibration method, which helps to improve the accuracy of autonomous measurement and processing of the robot.

[0122] The beneficial effects of implementing the embodiments of the present invention include: the embodiments of the present invention first construct a tool end coordinate transformation matrix based on the robot tool end, and after the measurement standard block is placed at a preset measurement position, scanning processing is performed to obtain point cloud data, robot end posture, scanning start point and scanning end point, and feature measurement position points are extracted from the point cloud data. Then, tool posture extraction processing is performed based on the target feature points to obtain the tool end posture, and then the robot position transformation point and the tool end position transformation point are calculated, and the objective function is constructed. Finally, the preset nonlinear optimization method is used to optimize the objective function to obtain the target calibration value, thereby realizing line laser calibration and improving accuracy and efficiency.

[0123] like Figure 3 As shown, an embodiment of the present invention further provides a robot line laser calibration device, comprising:

[0124] The first module 801 is used to construct a tool end coordinate transformation matrix according to the robot tool end;

[0125] The second module 802 is used to scan the measurement standard block after it is placed at the preset measurement position to obtain point cloud data, robot end position, scanning start point and scanning end point. The measurement standard block has target feature points, and the target feature points include convex feature points or concave feature points.

[0126] The third module 803 is used to extract feature measurement position points from the point cloud data;

[0127] The fourth module 804 is used to perform tool pose extraction processing based on the target feature points to obtain the tool end pose;

[0128] The fifth module 805 is used to calculate the robot position transformation point based on the robot end position, feature measurement position point, scanning start point and scanning end point;

[0129] The sixth module 806 is used to calculate the tool end position transformation point based on the initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end posture and the tool end posture;

[0130] The seventh module 807 is used to construct an objective function based on the robot position change point and the tool end position change point, and the optimization goal of the objective function is to minimize the objective function value;

[0131] The eighth module 808 is used to optimize the objective function using a preset nonlinear optimization method to obtain a target calibration value. The target calibration value is used as a line laser calibration result. The target calibration value includes a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value.

[0132] The contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0133] like Figure 4 As shown, an embodiment of the present invention further provides a computer device, including:

[0134] at least one processor 901;

[0135] At least one memory 902, configured to store at least one program;

[0136] When at least one program is executed by at least one processor, the at least one processor implements Figure 1 The method shown.

[0137] The contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0138] The embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program, which is executed by a processor to implement Figure 1 The method shown.

[0139] The contents of the above method embodiments are all applicable to the present storage medium embodiment. The functions specifically implemented by the present storage medium embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0140] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A robot line laser calibration method, characterized in that: The following steps are involved: According to the robot tool end, construct the tool end coordinate transformation matrix; After the measurement standard block is placed at a preset measurement position, scanning processing is performed to obtain point cloud data, robot end position, scanning start point and scanning end point. The measurement standard block has target feature points, and the target feature points include convex feature points or concave feature points. Extracting feature measurement location points from the point cloud data; Performing tool pose extraction processing based on the target feature points to obtain the tool end pose; Calculating a robot position transformation point according to the robot end position, the feature measurement position point, the scanning start point, and the scanning end point; Calculating a tool end position transformation point according to an initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end posture, and the tool end posture; Constructing an objective function according to the robot position change point and the tool end position change point, wherein the optimization goal of the objective function is to minimize the objective function value; The objective function is optimized using a preset nonlinear optimization method to obtain a target calibration value, which is used as a line laser calibration result. The target calibration value includes a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value.

2. The method according to claim 1, characterized in that The step of constructing a tool end coordinate transformation matrix based on the robot tool end includes: Performing a rough calibration process on the robot tool end using a preset robot tool coordinate system calibration method to obtain an initial tool coordinate transformation matrix; The tool end coordinate transformation matrix is ​​calculated based on the initial tool coordinate transformation matrix.

3. The method according to claim 1, characterized in that After the measurement standard block is placed at the preset measurement position, scanning processing is performed to obtain point cloud data, robot end position, scanning start point and scanning end point, including: After the measurement standard block is placed at a preset measurement position, a posture adjustment signal is generated, wherein the posture adjustment signal is used to control the robot to adjust to a preset measurement posture so that the laser scanning can detect the plurality of target feature points in the measurement standard block; Under the preset measurement posture, a scanning signal is generated, and the scanning signal is used to control the laser scanning device to scan the measurement standard block to obtain the point cloud data, the robot end position, the scanning start point and the scanning end point.

4. The method according to claim 3, characterized in that The tool posture extraction process is performed based on the target feature points to obtain the tool end posture, including: Under the preset measurement posture, a tool end movement signal is generated, and the tool end movement signal is used to control the robot tool end to move to the position of the target feature point to obtain the tool end posture.

5. The method according to claim 1, wherein The calculating of the robot position transformation point according to the robot end position, the feature measurement position point, the scanning starting point and the scanning end point includes: Calculate the line laser coordinate transformation matrix according to the initial line laser transformation offset value and the initial line laser Euler rotation angle value; Calculating a scanning direction according to the robot end position, the line laser coordinate conversion matrix, the scanning start point and the scanning end point; Performing plane projection processing on the scanning direction to obtain an x-axis projection direction and a z-axis projection direction; Calculating a first angle according to the x-axis projection direction and the y-axis of the robot end coordinate system; Calculating a second angle according to the z-axis projection direction and the y-axis of the robot end coordinate system; Calculating a feature position transformation point based on the first angle, the second angle, an x-axis component of the feature position transformation point, a z-axis component of the feature position transformation point, and the feature measurement position point; The robot position transformation point is calculated according to the characteristic position transformation point, the line laser coordinate conversion matrix and the robot end posture.

6. The method according to claim 1, wherein The objective function is constructed according to the robot position transformation point and the tool end position transformation point, including: Performing a first measurement process based on the robot position transformation point and the tool end position transformation point to obtain a first robot transformation point and a first tool transformation point; performing a second measurement process based on the robot position transformation point and the tool end position transformation point to obtain a second robot transformation point and a second tool transformation point, wherein a measurement posture of the second measurement process is different from a measurement posture of the first measurement process, and a placement position of the measurement standard block in the second measurement process is the same as the placement position of the measurement standard block in the first measurement process; performing a third measurement process based on the robot position transformation point and the tool end position transformation point to obtain a third robot transformation point and a third tool transformation point, wherein a measurement posture of the third measurement process is different from a measurement posture of the second measurement process, and a placement position of the measurement standard block in the third measurement process is the same as a placement position of the measurement standard block in the second measurement process; calculating a total position point distance based on the first robot transformation point, the first tool transformation point, the second robot transformation point, the second tool transformation point, the third robot transformation point, and the third tool transformation point; Calculating a distance between a first tool position point and a second tool position point according to the first tool transformation point and the second tool transformation point; Calculating a distance between the second tool position points according to the second tool transformation point and the third tool transformation point; Calculating a distance between a third tool position point and the first tool transformation point and the third tool transformation point; The objective function is constructed based on the total location point distance, the first tool location point distance, the second tool location point distance, and the third tool location point distance.

7. The method according to claim 5, characterized in that The calculating of the scanning direction according to the robot end position, the line laser coordinate conversion matrix, the scanning starting point and the scanning end point includes: The scanning direction is calculated according to the robot end position, the line laser coordinate conversion matrix, the scanning start point and the scanning end point using a scanning direction calculation formula. The scanning direction calculation formula is: Where, is the scanning direction, is the end pose of the robot, T em is the line laser coordinate transformation matrix, is the scanning endpoint, is the scanning starting point.

8. A robot line laser calibration device, characterized in that: include: The first module is used to construct a tool end coordinate transformation matrix according to the robot tool end; The second module is used to scan and process the measurement standard block after it is placed at a preset measurement position to obtain point cloud data, robot end position, scanning start point and scanning end point. The measurement standard block has target feature points, and the target feature points include convex feature points or concave feature points. A third module is used to extract feature measurement position points from the point cloud data; The fourth module is used to perform tool posture extraction processing based on the target feature points to obtain the tool end posture; A fifth module is used to calculate the robot position transformation point according to the robot end posture, the feature measurement position point, the scanning start point and the scanning end point; A sixth module is used to calculate a tool end position transformation point according to an initial tool end transformation offset value, the tool end coordinate transformation matrix, the robot end posture and the tool end posture; A seventh module is configured to construct an objective function based on the robot position change point and the tool end position change point, wherein the optimization goal of the objective function is to minimize the objective function value; The eighth module is used to optimize the objective function using a preset nonlinear optimization method to obtain a target calibration value. The target calibration value is used as a line laser calibration result. The target calibration value includes a target line laser conversion offset value, a target line laser Euler rotation angle value, and a target tool end conversion offset value.

9. A computer device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images