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

Abstract

The present invention provides a weld path planning method, system, and medium based on robot kinematics. The method comprises: obtaining three-dimensional weld data; establishing a robot kinematic model; coordinate conversion; path planning; and collision detection and optimization. During the path planning process, a collision detection algorithm is incorporated to perform collision detection. If a collision risk is detected on the robot path, an optimization sub-step is entered. If no collision risk exists, the current motion parameters are determined as optimized motion parameters, and the path corresponding to the current motion parameters is determined as the final planned path. Finally, a path execution control step is performed, in which the optimized motion parameters are applied to the robot control system to control the robot to move and weld along the final planned path. The present invention ensures path continuity and avoids collision risks, improving the accuracy and safety of the welding process, and has broad market prospects and economic benefits.

Description

Technical Field

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

[0002] Welding is a crucial process in modern industrial production, widely used in numerous fields, including automotive manufacturing, aerospace, and machining. With the continuous advancement of science and technology, robotic welding technology has gradually become mainstream, greatly improving welding quality and production efficiency with its advantages of high efficiency, stability, and precision.

[0003] However, traditional weld path planning methods have exposed numerous problems in practical applications. For one thing, traditional methods often result in path discontinuities. During the welding process, these discontinuous weld paths can cause unevenness and reduced strength at the weld joint, seriously impacting the quality of the welded product.

[0004] On the other hand, traditional weld path planning carries a high collision risk. In complex welding environments, the robot may collide with surrounding equipment, workpieces, and other components, which can not only damage the robot and equipment but also cause production interruptions and increase repair costs and time.

[0005] Furthermore, traditional methods struggle to meet the precision and safety requirements of modern industry. The inability to accurately plan the weld path can lead to weld deviations, impacting the product's dimensional accuracy and performance. Furthermore, the risk of collision poses a safety hazard to operators, increasing workplace risks.

[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] Prior art research on robot kinematics focuses on the motion characteristics and posture transformations of robots. This involves joint kinematics and end-effector kinematics, describing the robot's posture, coordinate system transformations, and the relationship between joint angles and end-effector posture. In weld path planning, this technology is used to transform the three-dimensional weld seam data into the robot's base coordinate system to determine the robot's joint angles or posture sequence.

[0008] Path planning algorithms calculate the optimal path for a robot from its starting position to its target. Geometric modeling, sampling search, and optimization algorithms are commonly used in weld path planning. These algorithms, based on the weld geometry and the robot's kinematic model, search for a suitable path to ensure the robot accurately follows the weld and welds.

[0009] Coordinate transformation is also essential for weld path planning. It requires converting the 3D weld seam data into the KUKA robot's machine base coordinate system. This involves coordinate system conversion and transformation operations, using calculations such as rotation matrices, translation vectors, and Euler angles to map the weld's position and orientation to the robot's joint angles or pose.

[0010] Collision detection is also crucial in weld path planning, as it ensures the robot's safety and avoids collisions with the workpiece or other obstacles. Collision detection technology uses the robot's geometric model and the environment model to detect collisions and adjust the robot's path to ensure safe welding.

[0011] A search of patent documents revealed an invention patent with publication number CN105739507B, which discloses an optimal path planning method for robot collision avoidance. The method includes the following steps: establishing a three-dimensional physical model of the workpiece, tooling, welding gun, and laser sensor; obtaining the target position of the workpiece when the welding gun is required through offline programming; setting / updating the rotation angle range and discreteness of each axis; obtaining the optimal rotation angle for each axis through a dynamic programming algorithm and collision testing; and determining whether the distance between the robot's actual position at the optimal rotation angle and the target position is less than the error distance. This patent only uses a specific algorithm and testing to find the optimal rotation angle, and the path planning method is simple.

[0012] In summary, in response to the above-mentioned problems of the existing technology, 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 path planning method based on robot kinematics provided by the present invention comprises the following steps:

[0015] A step of obtaining three-dimensional data of a weld seam, obtaining three-dimensional data of the weld seam;

[0016] The robot kinematics 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 is performed based on 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;

[0018] In the path planning step, the robot motion parameters are calculated using a path planning algorithm based on the robot kinematic model and the converted three-dimensional weld seam 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 obtaining three-dimensional data of the weld, three-dimensional data of the weld is obtained 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, the coordinate system conversion and coordinate transformation operations are performed using one of a rotation matrix, a translation vector or an Euler angle.

[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, 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 the 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 kinematic 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 kinematic model module and a robot kinematic model. The robot kinematic 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] The coordinate conversion module converts the three-dimensional data of the weld to the coordinate system of the robot base, performs coordinate conversion, and obtains the converted three-dimensional data of the weld;

[0034] The path planning module calculates the robot's motion parameters using a path planning algorithm based on the robot's kinematic model and the converted three-dimensional weld seam data;

[0035] The collision detection and optimization module performs collision detection based on the robot's motion parameters and combines the collision detection algorithm during the path planning process. If a collision risk is detected on the robot's path, it enters the optimization sub-step 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, which, when executed by a processor, implements the steps of the above-mentioned welding path planning method based on robot kinematics.

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

[0039] This invention achieves automated, precise, and efficient weld path planning, ensuring path continuity and improving welding accuracy and safety. Through collision detection and optimization, it effectively avoids collision risks and enhances system stability.

[0040] This invention can be applied in the welding industry, reducing the need for manual operation, labor costs, and human errors. It can also improve welding quality and efficiency, shorten production cycles, and adapt to complex welding environments, promising 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 upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

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

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

[0044] The present invention will be described in detail below with reference to specific embodiments. The following examples 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 skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0045] The present invention first acquires three-dimensional data of the weld using 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. The three-dimensional data of the weld is then converted from the weld coordinate system to the robot base coordinate system so that the robot can accurately identify the weld location. 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 along the path. If there is a collision risk, path optimization and adjustment are performed to ensure that the robot can complete the welding task safely and efficiently.

[0046] Example 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 seam is to obtain three-dimensional data of the weld seam.

[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 robot kinematics 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.

[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 based on 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 the 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] Example 2:

[0066] Figure 2 This is a functional module diagram of the 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 kinematic model module and a robot kinematic model. The robot kinematic 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] The coordinate conversion module converts the three-dimensional data of the weld to the coordinate system of the robot base, performs coordinate conversion, and obtains the converted three-dimensional data of the weld;

[0071] The path planning module calculates the robot's motion parameters using a path planning algorithm based on the robot's kinematic model and the converted three-dimensional weld seam data;

[0072] The collision detection and optimization module performs collision detection based on the robot's motion parameters and combines the collision detection algorithm during the path planning process. If a collision risk is detected on the robot's path, it enters the optimization sub-step 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 automation of the welding path planning method based on robot kinematics.

[0075] Example 3:

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

[0077] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention 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 a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0078] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A welding path planning method based on robot kinematics, characterized in that: The following steps are involved: A step of obtaining three-dimensional data of a weld seam, obtaining 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 based on 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, calculating the robot's motion parameters using a path planning algorithm based on the robot's kinematic model and the converted three-dimensional weld seam data; A collision detection and optimization step, based on the motion parameters of the robot, combines a collision detection algorithm to perform collision detection during the path planning process. If a collision risk is detected on the robot path, the optimization sub-step is entered; if no collision risk exists, 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, 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 KUKA robot used.

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 Euler angle is used to perform 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 during the path planning process to perform collision detection. 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, module for coordinate conversion, module for path planning, module for collision detection and optimization, and module for path execution control; The module for obtaining three-dimensional data of welds is used to obtain three-dimensional data of welds; The robot kinematic model establishment module establishes 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 based on 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 robot's motion parameters using a path planning algorithm based on the robot's kinematic model and the converted three-dimensional weld seam data; The collision detection and optimization module performs collision detection based on the robot's motion parameters and a collision detection algorithm during the path planning process. If a collision risk is detected on the robot's path, the module enters the optimization sub-step 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 perform welding operations 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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