Welding seam path planning method and system based on robot kinematics and medium

Abstract

The invention provides a welding seam path planning method and system based on robot kinematics and a medium. The method comprises the following steps: acquiring three-dimensional data of a welding seam; establishing a robot kinematics model; a coordinate conversion step; a path planning step; a collision detection and optimization step: performing collision detection in combination with a collision detection algorithm in the path planning process, and entering an optimization sub-step if it is detected that a collision risk exists on the robot path; if the collision risk does not exist, determining the current motion parameter as an optimized motion parameter, and determining a path corresponding to the current motion parameter as a final planning path; and a path execution control step: applying the optimized motion parameters to a robot control system, and controlling the robot to carry out movement and welding operation along the final planned path. According to the method, path continuity is achieved, the collision risk is avoided, the accuracy and safety of the welding process are improved, and wide market prospects and economic benefits are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of robot kinematics and path planning, and to coordinate system conversion and coordinate transformation operations, and in particular to a weld path planning method, system and medium based on robot kinematics. Background Art

[0002] In modern industrial production, welding is a vital process, which is widely used in many fields such as automobile manufacturing, aerospace, and mechanical processing. With the continuous advancement of science and technology, robot welding technology has gradually become the mainstream, which has greatly improved the welding quality and production efficiency with its advantages of high efficiency, stability, and precision.

[0003] However, traditional weld path planning methods have exposed many problems in practical applications. On the one hand, traditional methods often lead to path discontinuity. During the welding process, the discontinuity of the weld path will cause problems such as unevenness and reduced strength at the weld joint, seriously affecting the quality of the welded product.

[0004] On the other hand, traditional weld path planning has a high risk of collision. In a complex welding environment, the robot may collide with surrounding equipment, workpieces, etc., which will not only damage the robot and equipment, but also cause production interruptions and increase maintenance costs and time.

[0005] In addition, traditional methods are also difficult to meet the requirements of modern industry in terms of accuracy and safety. The inability to accurately plan the weld path may lead to welding deviations, affecting the dimensional accuracy and performance of the product. At the same time, the risk of collision also poses a safety hazard to operators and increases the danger of the workplace.

[0006] Therefore, weld path planning is an important task in the field of automated welding, which aims to enable the robot to automatically plan and execute paths in complex welding tasks.

[0007] In the prior art, robot kinematics studies the motion characteristics and posture transformation of robots, involving joint kinematics and end effector kinematics, which are used to describe the robot's posture, coordinate system transformation, and the relationship between joint angles and end effector postures. In weld path planning, this technology is used to transform the three-dimensional data of the weld into the robot's machine base coordinate system and determine the robot's joint angles or posture sequences.

[0008] The path planning algorithm is a method to calculate the best path for the robot from the starting position to the target position. In weld path planning, geometric model method, sampling search method and optimization algorithm are commonly used. These algorithms are based on the geometric shape of the weld and the kinematic model of the robot to find a suitable path to ensure that the robot can accurately follow the weld to move and weld.

[0009] Coordinate transformation is also indispensable in weld path planning, and the three-dimensional data of the weld needs to be converted into the coordinate system of the KUKA robot machine base. This involves coordinate system conversion and coordinate transformation operations, using rotation matrices, translation vectors, and Euler angles for calculations to correspond the position and direction of the weld to the joint angle or posture of the robot.

[0010] In addition, collision detection is also crucial in weld path planning. The robot's safety needs to be considered to avoid collisions with workpieces or other obstacles. Collision detection technology performs collision detection based on the robot's geometric model and environmental model, and ensures safe execution of welding tasks by adjusting the robot's path.

[0011] Through searching patent documents, it was found that the invention patent with publication number CN105739507B discloses an optimal path planning method for robot anti-collision, which includes the following steps: establishing a three-dimensional physical model of the workpiece, tooling, welding gun, and laser sensor; obtaining the target posture when the welding gun is required to weld the workpiece through offline programming; setting / updating the rotation angle range and discrete degree of each axis; obtaining the optimal rotation angle of each axis through dynamic programming algorithm and collision test; judging whether the distance between the actual posture of the robot at the optimal rotation angle and the target posture is less than the error distance. This patent only finds the optimal rotation angle based on a specific algorithm and test, and the path planning method is single.

[0012] In summary, in response to the above-mentioned problems of the prior art, studying a weld path planning method and system based on robot kinematics has become a key task that needs to be solved urgently. Summary of the invention

[0013] In view of the defects in the prior art, the present invention aims to achieve efficient and accurate weld path planning to avoid path discontinuity and collision risks.

[0014] A welding seam path planning method based on robot kinematics provided by the present invention comprises the following steps:

[0015] The step of obtaining three-dimensional data of the weld seam is to obtain three-dimensional data of the weld seam;

[0016] The steps of establishing a robot kinematic model are as follows: establishing a robot kinematic model, wherein the robot kinematic model includes the robot's joint coordinate system, the end effector coordinate system, and the relationship between the robot's joint angles and the end effector's position and posture;

[0017] A coordinate conversion step, performing coordinate conversion according to the relationship between the three-dimensional data of the weld and the coordinate system of the robot base, to obtain converted three-dimensional data of the weld;

[0018] In the path planning step, the robot motion parameters are calculated using the path planning algorithm based on the robot kinematic model and the converted three-dimensional weld data;

[0019] The collision detection and optimization step is based on the robot's motion parameters and combines the collision detection algorithm in the path planning process to perform collision detection. If a collision risk is detected on the robot's path, the optimization sub-step is entered; if there is no collision risk, the current motion parameters are determined as the optimized motion parameters, and the path corresponding to the current motion parameters is determined as the final planned path, and the path execution control step is entered;

[0020] In the path execution control step, the optimized motion parameters are applied to the robot control system to control the robot to move and weld along the final planned path.

[0021] Preferably, in the step of acquiring three-dimensional data of the weld, three-dimensional data of the weld is acquired by a sensor or a scanning device, and the three-dimensional data includes the shape, position and direction of the weld.

[0022] Preferably, in the step of establishing the robot kinematic model, the robot kinematic model is established based on the kinematic characteristics of the KUKA robot used.

[0023] Preferably, in the coordinate conversion step, a rotation matrix, a translation vector or Euler angle is used to perform the coordinate system conversion and coordinate transformation operations.

[0024] Preferably, in the path planning step, the path planning algorithm includes a geometric model method, a sampling search method and an optimization algorithm.

[0025] Preferably, in the path planning step, the motion parameters include joint angles or posture sequences, and different path planning algorithms calculate the joint angles or posture sequences of the robot, or calculate the joint angles and posture sequences simultaneously.

[0026] Preferably, in the collision detection and optimization step, the collision detection is performed based on the robot's geometric model and the environment model.

[0027] Preferably, the optimization sub-step includes the following sub-steps:

[0028] Parameter modification steps: modify the robot's motion parameters to obtain modified motion parameters;

[0029] Re-detection step: Based on the modified motion parameters, collision detection is performed in combination with the collision detection algorithm during the path planning process. If a collision risk is detected on the robot path, the parameter modification step is entered; if there is no collision risk, the current motion parameters are determined as the optimized motion parameters, and the path corresponding to the current motion parameters is determined as the final planned path, and the path execution control step is entered.

[0030] The present invention also provides a welding seam path planning system based on robot kinematics, comprising: a welding seam three-dimensional data acquisition module, a robot kinematics model establishment module, a coordinate conversion module, a path planning module, a collision detection and optimization module and a path execution control module;

[0031] A module for obtaining three-dimensional data of welds is used to obtain three-dimensional data of welds;

[0032] Establish a robot kinematics model module and a robot kinematics model. The robot kinematics model includes the joint coordinate system, the end effector coordinate system, and the relationship between the robot's joint angles and the end effector posture;

[0033] A coordinate conversion module performs coordinate conversion according to the relationship between the three-dimensional data of the weld and the coordinate system of the robot base to obtain the converted three-dimensional data of the weld;

[0034] The path planning module uses the path planning algorithm to calculate the robot's motion parameters based on the robot's kinematic model and the converted three-dimensional weld data;

[0035] The collision detection and optimization module performs collision detection based on the robot's motion parameters and the collision detection algorithm during the path planning process. If a collision risk is detected on the robot's path, the optimization sub-step is entered to obtain the optimized motion parameters and the final planned path.

[0036] The path execution control module applies the optimized motion parameters to the robot control system and controls the robot to move and weld along the final planned path.

[0037] The present invention also provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned welding seam path planning method based on robot kinematics are implemented.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention realizes the automation, precision and efficiency of weld path planning, ensures path continuity, improves welding accuracy and safety, effectively avoids collision risks and improves system stability through collision detection and optimization.

[0040] The present invention can be applied to the welding industry, reduce the need for manual operation, reduce labor costs and human errors, improve the quality and efficiency of welding tasks, shorten the production cycle, adapt to complex welding environments, and have broad market prospects and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0042] Figure 1 is a flow chart of a welding seam path planning method based on robot kinematics in an embodiment of the present invention;

[0043] Figure 2 It is a functional module diagram of a welding path planning method based on robot kinematics in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0045] The present invention first obtains the three-dimensional data of the weld through a three-dimensional scanner or sensor, and establishes a kinematic model of the robot, including the joint coordinate system, the end effector coordinate system, and the relationship between the joint angle and the end effector posture. Then, the three-dimensional data of the weld is converted from the weld coordinate system to the robot base coordinate system so that the robot can accurately identify the weld position. Based on the robot kinematic model and the converted weld data, the robot's joint angle or posture sequence is calculated, and collision detection is performed to avoid collision risks on the path. If there is a collision risk, the path is optimized and adjusted to ensure that the robot can complete the welding task safely and efficiently.

[0046] Embodiment 1:

[0047] Figure 1 This is a flow chart of a welding path planning method based on robot kinematics in an embodiment of the present invention.

[0048] like Figure 1 As shown, this embodiment provides a welding path planning method based on robot kinematics, comprising the following steps:

[0049] The step of obtaining three-dimensional data of the weld is to obtain three-dimensional data of the weld.

[0050] In this embodiment, three-dimensional data of the weld is acquired by a sensor or a scanning device, and the three-dimensional data includes the shape, position and direction of the weld.

[0051] The steps of establishing a robot kinematic model are to establish a robot kinematic model, which includes the robot's joint coordinate system, the end effector coordinate system, and the relationship between the robot's joint angles and the end effector posture.

[0052] In this embodiment, a robot kinematic model is established based on the kinematic characteristics of the KUKA robot used.

[0053] The coordinate conversion step performs coordinate conversion according to the relationship between the three-dimensional data of the weld and the coordinate system of the robot base to obtain the converted three-dimensional data of the weld.

[0054] In this embodiment, a rotation matrix, a translation vector or an Euler angle is used to perform coordinate system conversion and coordinate transformation operations to convert the three-dimensional data of the weld from the weld coordinate system to the robot base coordinate system.

[0055] In the path planning step, the robot's motion parameters are calculated using a path planning algorithm based on the robot's kinematic model and the converted three-dimensional weld data.

[0056] The motion parameters include joint angles or posture sequences. Different path planning algorithms calculate the joint angles or posture sequences of the robot, or calculate the joint angles and posture sequences at the same time to enable the robot to move and weld accurately along the weld path.

[0057] In this embodiment, the path planning algorithm includes a geometric model method, a sampling search method and an optimization algorithm.

[0058] The collision detection and optimization step is based on the robot's motion parameters and combines the collision detection algorithm to perform collision detection during the path planning process. If a collision risk is detected on the robot's path, the optimization sub-step is entered; if there is no collision risk, the current motion parameters are determined as the optimized motion parameters, and the path corresponding to the current motion parameters is determined as the final planned path, and the path execution control step is entered.

[0059] In this embodiment, collision detection is performed based on the robot's geometric model and the environment model.

[0060] The optimization sub-step includes the following sub-steps:

[0061] Parameter modification steps: modify the robot's motion parameters to obtain modified motion parameters;

[0062] In this embodiment, the motion parameters are modified using an interpolation method to achieve smooth path optimization and avoid collisions and sharp turns.

[0063] Re-detection step: Based on the modified motion parameters, collision detection is performed in combination with the collision detection algorithm during the path planning process. If a collision risk is detected on the robot path, the parameter modification step is entered; if there is no collision risk, the current motion parameters are determined as the optimized motion parameters, and the path corresponding to the current motion parameters is determined as the final planned path, and the path execution control step is entered.

[0064] In the path execution control step, the optimized motion parameters are applied to the robot control system to control the robot to move and weld along the final planned path.

[0065] Embodiment 2:

[0066] Figure 2 It is a functional module diagram of a welding path planning method based on robot kinematics in an embodiment of the present invention.

[0067] like Figure 2 As shown, this embodiment provides a weld path planning system based on robot kinematics, including: a weld three-dimensional data acquisition module, a robot kinematic model establishment module, a coordinate conversion module, a path planning module, a collision detection and optimization module, and a path execution control module.

[0068] A module for obtaining three-dimensional data of welds is used to obtain three-dimensional data of welds;

[0069] Establish a robot kinematics model module and a robot kinematics model. The robot kinematics model includes the joint coordinate system, the end effector coordinate system, and the relationship between the robot's joint angles and the end effector posture;

[0070] A coordinate conversion module performs coordinate conversion according to the relationship between the three-dimensional data of the weld and the coordinate system of the robot base to obtain the converted three-dimensional data of the weld;

[0071] The path planning module uses the path planning algorithm to calculate the robot's motion parameters based on the robot's kinematic model and the converted three-dimensional weld data;

[0072] The collision detection and optimization module performs collision detection based on the robot's motion parameters and the collision detection algorithm during the path planning process. If a collision risk is detected on the robot's path, the optimization sub-step is entered to obtain the optimized motion parameters and the final planned path.

[0073] The path execution control module applies the optimized motion parameters to the robot control system and controls the robot to move and weld along the final planned path.

[0074] The above modules cooperate with each other to realize the automated implementation of the weld path planning method based on robot kinematics.

[0075] Embodiment 3:

[0076] This embodiment provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned welding seam path planning method based on robot kinematics are implemented.

[0077] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0078] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A welding path planning method based on robot kinematics, characterized in that: The following steps are involved: The step of obtaining three-dimensional data of the weld seam is to obtain three-dimensional data of the weld seam; The robot kinematics model is established, wherein the robot kinematics model includes a robot joint coordinate system, an end effector coordinate system, and a relationship between the robot joint angles and the end effector posture; A coordinate conversion step, performing coordinate conversion according to the relationship between the three-dimensional data of the weld and the coordinate system of the robot base to obtain converted three-dimensional data of the weld; A path planning step, based on the robot kinematic model and the converted three-dimensional weld data, using a path planning algorithm to calculate the robot's motion parameters; The collision detection and optimization step is based on the motion parameters of the robot and combines the collision detection algorithm in the path planning process to perform collision detection. If a collision risk is detected on the robot path, the optimization sub-step is entered; if there is no collision risk, the current motion parameters are determined as the optimized motion parameters, and the path corresponding to the current motion parameters is determined as the final planned path, and the path execution control step is entered; The path execution control step applies the optimized motion parameters to the robot control system to control the robot to move and weld along the final planned path.

2. The welding path planning method based on robot kinematics according to claim 1 is characterized in that: In the step of acquiring three-dimensional data of the weld, three-dimensional data of the weld is acquired by a sensor or a scanning device, and the three-dimensional data includes the shape, position and direction of the weld.

3. The welding path planning method based on robot kinematics according to claim 1, characterized in that: In the step of establishing the robot kinematic model, the robot kinematic model is established based on the kinematic characteristics of the used KUKA robot.

4. The welding path planning method based on robot kinematics according to claim 1, characterized in that: In the coordinate conversion step, a rotation matrix, a translation vector or an Euler angle is used to perform the coordinate system conversion and coordinate transformation operations.

5. The welding path planning method based on robot kinematics according to claim 1, characterized in that: In the path planning step, the path planning algorithm includes a geometric model method, a sampling search method and an optimization algorithm.

6. The welding path planning method based on robot kinematics according to claim 1, characterized in that: In the path planning step, the motion parameters include joint angles or posture sequences, and different path planning algorithms calculate the joint angles or posture sequences of the robot, or calculate the joint angles and posture sequences simultaneously.

7. The welding path planning method based on robot kinematics according to claim 1, characterized in that: In the collision detection and optimization step, the collision detection is performed based on the robot's geometric model and the environment model.

8. The welding path planning method based on robot kinematics according to claim 1, characterized in that: The optimization sub-step includes the following sub-steps: Parameter modification step: modifying the motion parameters of the robot to obtain modified motion parameters; Re-detection step: Based on the modified motion parameters, a collision detection algorithm is combined to perform collision detection during the path planning process. If a collision risk is detected on the robot path, the parameter modification step is entered; If there is no collision risk, the current motion parameters are determined as optimized motion parameters, the path corresponding to the current motion parameters is determined as the final planned path, and the path execution control step is entered.

9. A welding path planning system based on robot kinematics, characterized in that: include: Module for acquiring weld 3D data, module for establishing robot kinematic model, coordinate conversion module, path planning module, collision detection and optimization module and path execution control module; The module for obtaining three-dimensional data of weld seams is used to obtain three-dimensional data of weld seams; The robot kinematic model building module builds a robot kinematic model, wherein the robot kinematic model includes a joint coordinate system, an end effector coordinate system, and a relationship between the robot's joint angles and the end effector's posture; The coordinate conversion module performs coordinate conversion according to the relationship between the three-dimensional data of the weld and the coordinate system of the robot base to obtain the converted three-dimensional data of the weld; The path planning module calculates the motion parameters of the robot using a path planning algorithm based on the robot kinematic model and the converted three-dimensional weld data; The collision detection and optimization module performs collision detection based on the motion parameters of the robot and in combination with the collision detection algorithm during the path planning process. If a collision risk is detected on the robot path, the optimization sub-step is entered to obtain the optimized motion parameters and the final planned path. The path execution control module applies the optimized motion parameters to the robot control system to control the robot to move and weld along the final planned path.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the welding path planning method based on robot kinematics according to any one of claims 1 to 8 are implemented.

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