Robot kinematic calibration method, device and electronic equipment

Abstract

The present invention provides a robot kinematic calibration method, device and electronic equipment, which establishes a measurement coordinate system in the workspace where the robot is located, sets a distance sensor at its origin, and sets encoders on two mutually perpendicular coordinate axes. The robot is moved to multiple calibration positions by teaching. Based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder, the absolute position of the calibration position in the measurement coordinate system is determined. Based on the absolute positions of multiple calibration position points, the calibration of the kinematic calibration model and the calibration of the transformation relationship between the measurement coordinate system and the robot base coordinate system are realized. This solution uses a distance sensor for distance measurement and two vertically arranged encoders to realize rotation angle measurement. It can measure the absolute position of each calibration position point and then realize kinematic calibration, and can obtain better calibration results with a simple model.

Description

Technical Field

[0001] The present invention relates to the field of control technology, and in particular to a robot kinematics calibration method, device and electronic equipment. Background Art

[0002] To ensure that robots accurately perform their tasks, kinematic calibration is often necessary to correct errors introduced during installation and operation. Therefore, robot kinematic calibration is a necessary process to ensure that robots operate accurately and reliably as designed, and is crucial for improving production efficiency and product quality.

[0003] Among existing kinematic calibration methods, laser trackers and three-dimensional coordinate measuring machines are primarily used. Laser trackers offer high precision, a wide measurement range, and are relatively easy to use, but they are very expensive, and the dynamic measurement process has speed limitations, making them prone to light interruption. Three-dimensional coordinate measuring machines are highly efficient and high-precision measuring devices based on precision machinery, but they take up a lot of space and are expensive. In contrast, wire-drawn displacement sensors offer the advantages of high precision, low cost, ease of operation, simple installation, and a wide measurement range.

[0004] Current kinematic calibration methods based on wire-type displacement sensors typically determine the direction vector and distance corresponding to each robot position, then calculate the relative distance between two positions. This is then combined with the robot's kinematic equations to calibrate the robot. Because this method uses indirect measurement, it can result in incomplete data, affecting the accuracy of identifying the robot's structural parameters. Furthermore, strict requirements are placed on the placement of each sensor, placing high demands on sensor installation accuracy, and errors can affect calibration results.

[0005] In addition, existing technologies also use a single sensor combined with multiple inclinometers. However, this approach places high demands on the interconnection, relative movement, and installation precision of the sensors and inclinometers. Furthermore, the measurement process involves multiple coordinate systems, and the multiple coordinate system conversions increase computational complexity. Summary of the Invention

[0006] The purpose of the embodiments of the present invention is to provide a robot kinematics calibration method, device and electronic equipment to achieve high-accuracy robot kinematics calibration.

[0007] In a first aspect, the present invention provides a robot kinematic calibration method, the method comprising:

[0008] A measurement coordinate system is established in the workspace where the robot is located, wherein a distance sensor is provided at the origin of the measurement coordinate system, and encoders are respectively provided on a first coordinate axis and a second coordinate axis perpendicular to each other of the measurement coordinate system;

[0009] Moving the robot to a plurality of calibrated positions by teaching;

[0010] For each of the calibration position points, determining the absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder;

[0011] Based on the absolute positions of the multiple calibration position points, the kinematic calibration model is calibrated and the transformation relationship between the measurement coordinate system and the robot base coordinate system is calibrated.

[0012] In an optional embodiment, the step of calibrating the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the absolute positions of the multiple calibration position points includes:

[0013] Obtaining the position of the calibration point in the robot base coordinate system;

[0014] determining a position error based on the absolute position of the robot and the position in the robot base coordinate system;

[0015] Based on the position errors respectively corresponding to the plurality of calibration position points, the kinematic calibration model is calibrated and the transformation relationship between the measurement coordinate system and the robot base coordinate system is calibrated.

[0016] In an optional embodiment, the step of determining the absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder includes:

[0017] Based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder, a homogeneous transformation matrix is established between the measurement coordinate system and the robot end coordinate system;

[0018] The absolute position of the calibration point in the measurement coordinate system is obtained based on the homogeneous transformation matrix.

[0019] In an optional embodiment, the step of obtaining the position of the calibration point in the robot base coordinate system includes:

[0020] Constructing a transformation relationship between adjacent joints of the robot at the calibration position based on structural parameters in a kinematic calibration model;

[0021] Obtaining a total transformation matrix based on a transformation relationship between a plurality of adjacent joints of the robot;

[0022] The position of the calibration point in the robot base coordinate system is determined according to the total transformation matrix.

[0023] In an optional embodiment, the step of determining the position error based on the absolute position of the robot and the position in the robot base coordinate system comprises:

[0024] Converting the absolute position of the calibration point in the measurement coordinate system into a converted position in the robot base coordinate system;

[0025] A position error is determined based on the position in the robot base coordinate system and the transformed position.

[0026] In an optional embodiment, the step of calibrating the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the position errors corresponding to the plurality of calibration position points includes:

[0027] Based on the position errors respectively corresponding to the plurality of calibration position points, error values of various structural parameters in the kinematic calibration model and error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system are obtained.

[0028] In an optional embodiment, the step of obtaining error values of various structural parameters in the kinematic calibration model and error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system based on position errors corresponding to the plurality of calibration position points includes:

[0029] Based on the position errors respectively corresponding to the plurality of calibration position points, the original values of the structural parameters in the kinematic calibration model, and the original values of the transformation relationship between the measurement coordinate system and the robot base coordinate system, a nonlinear equation group regarding the error values of the structural parameters and the error values of the transformation relationship is constructed;

[0030] The nonlinear equation group is optimized and solved to obtain the error value of each structural parameter and the error value of the transformation relationship.

[0031] In an optional embodiment, the original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained by:

[0032] For each of the calibrated position points, obtaining a rotation angle and a translation amount of the robot relative to each coordinate axis of the robot base coordinate system at the calibrated position point;

[0033] An original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained based on the rotation angle and the translation amount.

[0034] In a second aspect, the present invention provides a robot kinematic calibration device, the device comprising:

[0035] An establishment module is used to establish a measurement coordinate system in the workspace where the robot is located, wherein a distance sensor is provided at the origin of the measurement coordinate system, and encoders are respectively provided on a first coordinate axis and a second coordinate axis perpendicular to each other of the measurement coordinate system;

[0036] A teaching module, used for moving the robot to a plurality of calibrated positions by teaching;

[0037] a determination module, configured to determine, for each of the calibration position points, an absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each of the encoders;

[0038] The calibration module is used to calibrate the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the absolute positions of the multiple calibration position points.

[0039] In a third aspect, the present invention provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the steps of the method described in any one of the aforementioned embodiments are implemented.

[0040] The beneficial effects of the embodiments of the present invention include, for example:

[0041] The present invention provides a robot kinematic calibration method, device and electronic equipment. A measurement coordinate system is established in the workspace where the robot is located. The position of the distance sensor is set at the origin of the measurement coordinate system, and encoders are respectively set on the first coordinate axis and the second coordinate axis that are perpendicular to each other. The robot is moved to multiple calibration positions by teaching. Based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder, the absolute position of the calibration position in the measurement coordinate system is determined. Based on the absolute positions of multiple calibration position points, the calibration of the kinematic calibration model and the calibration of the transformation relationship between the measurement coordinate system and the robot base coordinate system are realized. This solution uses a distance sensor to measure the distance and two vertically arranged encoders to measure the rotation angle, which can realize the three-dimensional position measurement of any point in space. By measuring the absolute position of each calibration position point for kinematic calibration, a better calibration result can be obtained, and the model is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 A flowchart of a robot kinematic calibration method provided by an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of a measurement coordinate system provided by an embodiment of the present invention;

[0045] Figure 3 for Figure 1 Flowchart of the sub-steps included in S13;

[0046] Figure 4 for Figure 1 Flowchart of the sub-steps included in S14;

[0047] Figure 5 for Figure 4 Flowchart of the sub-steps included in S141;

[0048] Figure 6 for Figure 4 Flowchart of the sub-steps included in S142;

[0049] Figure 7 for Figure 4 Flowchart of the sub-steps included in S143;

[0050] Figure 8 A functional module block diagram of a robot kinematics calibration device provided by an embodiment of the present invention;

[0051] Figure 9 This is a structural block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention.

[0053] See also Figure 1 , which is a flow chart of a robot kinematic calibration method provided in an embodiment of the present invention. This robot kinematic calibration method can be performed by a robot kinematic calibration device. This robot kinematic calibration device can be implemented using software and / or hardware and can be configured in an electronic device such as a computer, server, or programmable logic controller. The detailed steps of this robot kinematic calibration method are described below.

[0054] S11, establishing a measurement coordinate system in the workspace where the robot is located, wherein a distance sensor is provided at the origin of the measurement coordinate system, and encoders are respectively provided on a first coordinate axis and a second coordinate axis perpendicular to each other of the measurement coordinate system.

[0055] S12, moving the robot to a plurality of calibrated position points by teaching.

[0056] S13, for each of the calibration position points, based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each of the encoders, determine the absolute position of the calibration position point in the measurement coordinate system.

[0057] S14, based on the absolute positions of the multiple calibration position points, realize the calibration of the kinematic calibration model and the calibration of the transformation relationship between the measurement coordinate system and the robot base coordinate system.

[0058] In this embodiment, Figure 2 The figure shows a schematic diagram of the established measurement coordinate system. Two perpendicular axes are constructed in the robot's workspace. These axes coincide with the first and second coordinate axes, respectively. The first and second coordinate axes can be the X-axis and Z-axis, respectively, and the Y-axis is determined according to the right-hand rule. The origin of the measurement coordinate system is the location of the distance sensor, and encoders are installed on the X-axis and Z-axis.

[0059] Among them, the distance sensor can be a wire sensor, which can measure the distance between itself and the robot, and the encoder can measure the rotation angle of the robot in the workspace relative to the X-axis and Z-axis.

[0060] The robot is moved to multiple calibration points through teaching. The selected calibration points should be evenly distributed within the robot's workspace, and the robot can be controlled to assume a variety of different positions. This increases the diversity of the data used for calibration and ensures accuracy.

[0061] For each calibration point, the distance sensor determines the distance between itself and the robot at that point, while the two encoders measure the robot's rotation angles relative to the X and Z axes, respectively. By transforming the measurement coordinate system into the robot's end-point coordinate system, the absolute position of the calibration point in the measurement coordinate system, represented by the distance and the two rotation angles, can be determined.

[0062] Calibration of the kinematic calibration model primarily involves calibrating the structural parameters within the model. While these parameters are known, they can vary due to installation errors or long-term robot use. Therefore, calibration of the structural parameters within the kinematic calibration model is necessary to eliminate the impact of these errors on control.

[0063] Similarly, the calibration of the transformation relationship between the measurement coordinate system and the robot base coordinate system is also to avoid the influence of errors in the measurement results in the robot base coordinate system.

[0064] In this embodiment, the kinematic calibration model is calibrated based on the absolute positions of the multiple calibration position points, and the transformation relationship between the measurement coordinate system and the robot base coordinate system is calibrated.

[0065] This solution uses a distance sensor for distance measurement and two perpendicularly arranged encoders for rotation angle measurement, enabling 3D position measurement of any point in space. Kinematic calibration is performed by measuring the absolute position of each calibration point, resulting in superior calibration results and a simple model.

[0066] See also Figure 3 In this embodiment, the step of determining the absolute position of the calibration point in the measurement coordinate system based on the detected distance and rotation angle can be achieved by:

[0067] S131 , establishing a homogeneous transformation matrix between the measurement coordinate system and the robot end coordinate system based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder.

[0068] S132: Obtain the absolute position of the calibration point in the measurement coordinate system based on the homogeneous transformation matrix.

[0069] In this embodiment, the measurement coordinate system is denoted as [M], the robot end coordinate system is denoted as [P], the distance detected by the distance sensor is denoted as L, the rotation angle of the robot around the X axis detected by the encoder is β, and the rotation angle around the Z axis is γ.

[0070] Based on the detected distance L, rotation angles β and γ, the homogeneous transformation matrix between the measurement coordinate system and the robot end coordinate system can be established :

[0071]

[0072] Extract the above homogeneous transformation matrix The first three rows of the fourth column are the absolute positions of the calibration points in the measurement coordinate system, which are recorded as .

[0073] Based on the presence of multiple calibration points, the absolute position of each calibration point in the measurement coordinate system can be obtained. Figure 4 , the steps of achieving calibration based on the absolute positions of multiple calibration points can be achieved in the following ways:

[0074] S141, obtaining the position of the calibration point in the robot base coordinate system.

[0075] S142 , determining a position error based on the absolute position of the robot and the position in the robot base coordinate system.

[0076] S143, based on the position errors respectively corresponding to the plurality of calibration position points, realize calibration of the kinematic calibration model and calibration of the transformation relationship between the measurement coordinate system and the robot base coordinate system.

[0077] See also Figure 5 In this embodiment, the step of obtaining the position of the calibration point in the robot base coordinate system can be achieved by:

[0078] S1411, constructing a transformation relationship between adjacent joints of the robot at the calibration position based on the structural parameters in the kinematic calibration model.

[0079] S1412: Obtain a total transformation matrix based on the transformation relationship between multiple adjacent joints of the robot.

[0080] S1413: Determine the position of the calibration point in the robot base coordinate system according to the total transformation matrix.

[0081] In this embodiment, the structural parameters of the robot, i.e., the structural parameters, are kinematically modeled in the following manner. Four parameters are defined in the kinematic model to describe the relationship between two adjacent joints of the robot. The structural parameters include 、 、 、 , where i represents the degree of freedom and the value of i ranges from 1 to 6. Represents the distance from joint i to i+1 in the x-axis direction, represents the rotation angle of the z-axis from joint i to joint i+1, represents the vertical distance from the z-axis of joint i to the x-axis of joint i+1, Indicates the rotation angle of the x-axis from joint i to joint i+1.

[0082] Based on the above structural parameters, the transformation relationship between adjacent joints of the robot is characterized by the following method:

[0083]

[0084] In this embodiment, assuming that the robot has six degrees of freedom, the total transformation matrix of the transformation relationship between multiple adjacent joints of the robot is As shown below:

[0085]

[0086] in:

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] , , ,

[0100] In this embodiment, the total transformation matrix is taken The elements of the first three rows of the fourth column are the positions of the calibration points in the robot base coordinate system, which are recorded as .

[0101] After obtaining the absolute position of each calibration point in the measurement coordinate system and the position of each calibration point in the robot base coordinate system, refer to Figure 6 , the step of determining the position error based on the absolute position of the robot and the position in the robot base coordinate system can be achieved by:

[0102] S1421: Convert the absolute position of the calibration point in the measurement coordinate system into a converted position in the robot base coordinate system.

[0103] S1422: Determine a position error based on the position in the robot base coordinate system and the converted position.

[0104] In this embodiment, the homogeneous transformation matrix between the robot base coordinate system [B] and the measurement coordinate system [M] is established based on the following method: :

[0105]

[0106] in, 、 and are the rotation angles of the measurement coordinate system around the x, y, and z axes of the robot base coordinate system, 、 and is the translation of the measurement coordinate system in the x, y, and z axes of the robot base coordinate system. The parameters related to the transformation relationship between the measurement coordinate system and the robot base coordinate system can be expressed as .

[0107] The conversion position of the calibration point in the robot base coordinate system can be obtained by multiplying the homogeneous transformation matrix between the robot base coordinate system and the measurement coordinate system by the absolute position of the calibration point. , the calculation formula is as follows:

[0108]

[0109] The position error can be obtained by subtracting the transformed position from the position of the calibration point in the robot base coordinate system. , the calculation formula is as follows:

[0110]

[0111] From the above, it can be seen that the calibration of the kinematic calibration model is essentially the calibration of the error values of each structural parameter in the kinematic calibration model. The calibration of the transformation relationship between the measurement coordinate system and the robot base coordinate system is essentially the calibration of the error values of each parameter in the transformation relationship.

[0112] Therefore, in this embodiment, when calibrating the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the position errors of multiple calibration position points, it is achieved by the following methods:

[0113] Based on the position errors respectively corresponding to the plurality of calibration position points, error values of various structural parameters in the kinematic calibration model and error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system are obtained.

[0114] Among them, what needs to be calibrated is the error value of each structural parameter in the kinematic calibration model, that is, the structural parameter 、 、 、 The respective error values can be expressed as 、 、 、 In addition, the error values of various parameters in the transformation relationship between the measurement coordinate system and the robot base coordinate system can also be calibrated, that is, 、 、 、 、 and The respective error values can be expressed as 、 、 、 、 and .

[0115] See also Figure 7 In this embodiment, the specific implementation of the calibration is as follows:

[0116] S1431, based on the position errors corresponding to the multiple calibration position points, the original values of the structural parameters in the kinematic calibration model, and the original values of the transformation relationship between the measurement coordinate system and the robot base coordinate system, a nonlinear equation group about the error values of the structural parameters and the error values of the transformation relationship is constructed.

[0117] S1432: Optimize and solve the nonlinear equation group to obtain the error value of each structural parameter and the error value of the transformation relationship.

[0118] In this embodiment, the position error is represented by the position of the calibration position point in the robot base coordinate system and the absolute position of the calibration position point in the measurement coordinate system converted to the converted position in the robot base coordinate system.

[0119] The position of the calibration position point in the robot base coordinate system is represented by the structural parameters (original values of the structural parameters) in the kinematic calibration model, and the transformed position of the calibration position point is represented by the absolute position and the homogeneous transformation matrix between the robot base coordinate system and the measurement coordinate system, that is, by the original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system.

[0120] Therefore, the position error can be characterized by the original values of the structural parameters in the kinematic calibration model and the original values of the transformation relationship between the measurement coordinate system and the robot base coordinate system.

[0121] The original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained in the following way:

[0122] For each of the calibration position points, the rotation angle and translation amount of the robot relative to each coordinate axis of the robot base coordinate system at the calibration position point are obtained; and based on the rotation angle and translation amount, the original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained.

[0123] In this embodiment, the original value of the transformation relationship between the obtained measurement coordinate system and the robot base coordinate system is represented as follows: .

[0124] In this embodiment, by performing full differentiation on the position error and using the total differential equation to approximate the kinematic error equation, the robot kinematic error calibration model shown below can be obtained:

[0125]

[0126] in:

[0127]

[0128]

[0129] In the above equation, The 30 parameters included in are the error values of the structural parameters to be solved and the error values of the transformation relationship. Based on the multiple position errors, a nonlinear equation group can be established based on the multiple position errors. The values corresponding to each position error are substituted into the nonlinear equation group for optimization and solution. For example, the least squares method can be used for optimization and solution. Finally, The values of each parameter in , that is, the error values of each structural parameter and the error value of the transformation relationship.

[0130] Based on this, when the error values of various structural parameters in the kinematic calibration model are obtained, these error values can be used to correct these structural parameters, thereby avoiding problems that affect control accuracy during the control process. Similarly, when the error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system are obtained, these error values can be used to correct various parameters in the transformation relationship between the measurement coordinate system and the robot base coordinate system during actual application, thereby avoiding problems that affect control accuracy.

[0131] The robot kinematic calibration method provided in this embodiment uses a distance sensor for distance measurement and two perpendicularly arranged encoders for rotation angle measurement, enabling the three-dimensional position measurement of any point in space. This solution achieves good kinematic calibration by measuring the absolute position of each calibration point. Furthermore, the model structure in this solution is simple, requiring only one measurement coordinate system, rather than multiple coordinate systems as required in the prior art. This avoids the increased computational complexity associated with multiple coordinate system conversions.

[0132] Based on the same inventive concept, please refer to Figure 8 , shows a schematic diagram of the functional modules of the robot kinematic calibration device provided by an embodiment of the present invention. This embodiment can divide the functional modules of the robot kinematic calibration device according to the above-mentioned method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present invention is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0133] For example, when each functional module is divided into corresponding functional modules, Figure 8 The robot kinematic calibration device shown is only a schematic diagram of the device. The robot kinematic calibration device may include a building module, a teaching module, a determination module, and a calibration module. The functions of each functional module of the robot kinematic calibration device are described in detail below.

[0134] An establishment module is used to establish a measurement coordinate system in the workspace where the robot is located, wherein a distance sensor is provided at the origin of the measurement coordinate system, and encoders are respectively provided on a first coordinate axis and a second coordinate axis perpendicular to each other of the measurement coordinate system;

[0135] It can be understood that the above-mentioned establishment module can be used to execute the above-mentioned S11. For the detailed implementation of the establishment module, reference can be made to the relevant content of the above-mentioned S11.

[0136] A teaching module, used for moving the robot to a plurality of calibrated positions by teaching;

[0137] It can be understood that the above teaching module can be used to execute the above S12. For the detailed implementation of the teaching module, reference can be made to the relevant content of the above S12.

[0138] a determination module, configured to determine, for each of the calibration position points, an absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each of the encoders;

[0139] It can be understood that the above-mentioned determination module can be used to execute the above-mentioned S13. For the detailed implementation of the determination module, reference can be made to the relevant content of the above-mentioned S13.

[0140] The calibration module is used to calibrate the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the absolute positions of the multiple calibration position points.

[0141] It can be understood that the calibration module can be used to execute the above S14. For the detailed implementation of the calibration module, reference can be made to the relevant content of the above S14.

[0142] In a possible implementation, the calibration module may be specifically used to:

[0143] Obtaining the position of the calibration point in the robot base coordinate system;

[0144] determining a position error based on the absolute position of the robot and the position in the robot base coordinate system;

[0145] Based on the position errors respectively corresponding to the plurality of calibration position points, the kinematic calibration model is calibrated and the transformation relationship between the measurement coordinate system and the robot base coordinate system is calibrated.

[0146] In a possible implementation, the above-mentioned determination module may be used to:

[0147] Based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder, a homogeneous transformation matrix is established between the measurement coordinate system and the robot end coordinate system;

[0148] The absolute position of the calibration point in the measurement coordinate system is obtained based on the homogeneous transformation matrix.

[0149] In a possible implementation, the determination module may be configured to obtain the position of the calibration point in the robot base coordinate system in the following manner:

[0150] Constructing a transformation relationship between adjacent joints of the robot at the calibration position based on structural parameters in a kinematic calibration model;

[0151] Obtaining a total transformation matrix based on a transformation relationship between a plurality of adjacent joints of the robot;

[0152] The position of the calibration point in the robot base coordinate system is determined according to the total transformation matrix.

[0153] In one possible implementation, the calibration module may be used to determine the position error in the following manner:

[0154] Converting the absolute position of the calibration point in the measurement coordinate system into a converted position in the robot base coordinate system;

[0155] A position error is determined based on the position in the robot base coordinate system and the transformed position.

[0156] In a possible implementation, the calibration module may be specifically used to:

[0157] Based on the position errors respectively corresponding to the plurality of calibration position points, error values of various structural parameters in the kinematic calibration model and error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system are obtained.

[0158] In a possible implementation, the calibration module may be specifically used to:

[0159] Based on the position errors respectively corresponding to the plurality of calibration position points, the original values of the structural parameters in the kinematic calibration model, and the original values of the transformation relationship between the measurement coordinate system and the robot base coordinate system, a nonlinear equation group regarding the error values of the structural parameters and the error values of the transformation relationship is constructed;

[0160] The nonlinear equation group is optimized and solved to obtain the error value of each structural parameter and the error value of the transformation relationship.

[0161] In one possible implementation, the calibration module may be used to obtain the original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system in the following manner:

[0162] For each of the calibrated position points, obtaining a rotation angle and a translation amount of the robot relative to each coordinate axis of the robot base coordinate system at the calibrated position point;

[0163] An original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained based on the rotation angle and the translation amount.

[0164] Figure 9 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device may be a computer device, a server, a notebook computer, etc. Figure 9 As shown, the electronic device includes one or more processors and a memory; the processor in the electronic device may be one or more, Figure 8 A processor is taken as an example; the memory is used to store one or more programs; the one or more programs are executed by one or more processors, so that the one or more processors implement the robot kinematic calibration method as any one of the embodiments of the present invention.

[0165] The electronic device may further include: an input device and an output device.

[0166] The processor, memory, input device and output device in the electronic device can be connected through a bus or other means. Figure 9 The bus connection is taken as an example.

[0167] The memory in the electronic device serves as a computer-readable storage medium and can be used to store one or more programs. The programs can be software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the robot kinematic calibration method provided in the embodiments of the present invention. The processor executes the software programs, instructions, and modules stored in the memory to execute various functional applications and data processing of the terminal device, thereby implementing the robot kinematic calibration method in the above-mentioned method embodiment.

[0168] The memory may include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function, and the data storage area may store data generated based on the use of the device. Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0169] In some embodiments, the memory may further include a memory remotely located relative to the processor, and the remote memory may be connected to the device via a network. Examples of the aforementioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0170] The input device can be used to receive input digital or character information and generate key signal input related to user settings and function control of the device. The output device can include a display device such as a display screen.

[0171] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, it can also be used to execute the robot kinematic calibration method provided by any embodiment of the present invention.

[0172] The computer-readable storage medium of the embodiment of the present invention may adopt any combination of one or more computer-readable media. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination thereof. More specific examples of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable CD-ROM, an optical storage device, a magnetic storage device, or any suitable combination thereof. The computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device or device.

[0173] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such a propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0174] The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wire, optical cable, radio frequency (RF), etc., or any suitable combination of the foregoing.

[0175] Computer program code for performing the operations of the present invention may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages such as Java, Smalltalk, C++, and conventional procedural programming languages such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0176] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A robot kinematic calibration method, characterized in that: The method comprises: A measurement coordinate system is established in the workspace where the robot is located, wherein a distance sensor is provided at the origin of the measurement coordinate system, and encoders are respectively provided on a first coordinate axis and a second coordinate axis perpendicular to each other of the measurement coordinate system; Moving the robot to a plurality of calibrated positions by teaching; For each of the calibration position points, determining the absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder; Obtaining the position of the calibration point in the robot base coordinate system; determining a position error based on the absolute position of the robot and the position in the robot base coordinate system; Based on the position errors respectively corresponding to the plurality of calibration position points, the kinematic calibration model is calibrated and the transformation relationship between the measurement coordinate system and the robot base coordinate system is calibrated.

2. The robot kinematic calibration method according to claim 1, characterized in that: The step of determining the absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder comprises: Based on the distance between the distance sensor and the robot and the rotation angle of the robot relative to the corresponding coordinate axis detected by each encoder, a homogeneous transformation matrix is established between the measurement coordinate system and the robot end coordinate system; The absolute position of the calibration point in the measurement coordinate system is obtained based on the homogeneous transformation matrix.

3. The robot kinematic calibration method according to claim 1, characterized in that: The step of obtaining the position of the calibration point in the robot base coordinate system includes: Constructing a transformation relationship between adjacent joints of the robot at the calibration position based on structural parameters in a kinematic calibration model; Obtaining a total transformation matrix based on a transformation relationship between a plurality of adjacent joints of the robot; The position of the calibration point in the robot base coordinate system is determined according to the total transformation matrix.

4. The robot kinematic calibration method according to claim 1, characterized in that: The step of determining the position error based on the absolute position of the robot and the position in the robot base coordinate system comprises: Converting the absolute position of the calibration point in the measurement coordinate system into a converted position in the robot base coordinate system; A position error is determined based on the position in the robot base coordinate system and the transformed position.

5. The robot kinematic calibration method according to claim 1, characterized in that: The step of calibrating the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the position errors respectively corresponding to the plurality of calibration position points comprises: Based on the position errors respectively corresponding to the plurality of calibration position points, error values of various structural parameters in the kinematic calibration model and error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system are obtained.

6. The robot kinematic calibration method according to claim 5, characterized in that: The step of obtaining error values of various structural parameters in the kinematic calibration model and error values of the transformation relationship between the measurement coordinate system and the robot base coordinate system based on position errors corresponding to the plurality of calibration position points includes: Based on the position errors respectively corresponding to the plurality of calibration position points, the original values of the structural parameters in the kinematic calibration model, and the original values of the transformation relationship between the measurement coordinate system and the robot base coordinate system, a nonlinear equation group regarding the error values of the structural parameters and the error values of the transformation relationship is constructed; The nonlinear equation group is optimized and solved to obtain the error value of each structural parameter and the error value of the transformation relationship.

7. The robot kinematic calibration method according to claim 6, characterized in that: The original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained in the following way: For each of the calibrated position points, obtaining a rotation angle and a translation amount of the robot relative to each coordinate axis of the robot base coordinate system at the calibrated position point; An original value of the transformation relationship between the measurement coordinate system and the robot base coordinate system is obtained based on the rotation angle and the translation amount.

8. A robot kinematic calibration device, characterized in that: For implementing the robot kinematic calibration method according to any one of claims 1 to 7, the device comprises: An establishment module is used to establish a measurement coordinate system in the workspace where the robot is located, wherein a distance sensor is provided at the origin of the measurement coordinate system, and encoders are respectively provided on a first coordinate axis and a second coordinate axis perpendicular to each other of the measurement coordinate system; A teaching module, used for moving the robot to a plurality of calibrated positions by teaching; a determination module, configured to determine, for each of the calibration position points, an absolute position of the calibration position point in the measurement coordinate system based on the distance between the robot and the distance sensor detected by the distance sensor and the rotation angle of the robot relative to the corresponding coordinate axis detected by each of the encoders; The calibration module is used to calibrate the kinematic calibration model and the transformation relationship between the measurement coordinate system and the robot base coordinate system based on the absolute positions of the multiple calibration position points.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

Images