Welding method and system for cooperatively controlling movable chassis and mechanical arm of movable welding platform

Abstract

The invention provides a welding method and system for cooperative control of a movable chassis and a mechanical arm of a movable welding platform, which can realize synchronous control of chassis movement and mechanical arm welding, and comprises the following steps: step 1, acquiring path information of a target welding seam to be welded and real-time pose information of the movable chassis in a global coordinate system in real time; 2, a unified system kinematics model of the chassis and the mechanical arm is established, and according to the unified system kinematics model, the target welding seam path is decomposed into a chassis target track of the movable chassis and a mechanical arm target track of the mechanical arm; step 3, controlling the mobile chassis to advance along the chassis target track; and 4, according to the deviation between the real-time pose information of the movable chassis and the chassis target track, the compensation motion needing to be executed by the mechanical arm is obtained through calculation in combination with the mechanical arm target track, and the mechanical arm executes the compensation motion.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of intelligent manufacturing and robot control, in particular, to a collaborative control method and system applied to the continuous long-weld-seam welding scene of large steel structural members such as ships, heavy steel structures, etc., and more particularly to a welding method and system for collaborative control of a mobile chassis and a mechanical arm. BACKGROUND

[0002] In the fields of shipbuilding, bridge construction, heavy machinery processing, etc., welding of large steel structural members is a key process link. Large steel structural members are usually large in size, complex in structure, and difficult to move, and the welds thereon are often continuous and long-distance distributed.

[0003] At present, the robot system applied to automatic welding is mainly divided into fixed type and guide rail type. The fixed welding robot has a limited working range and cannot cover the long welds on large workpieces, so it needs to be frequently redeployed or rely on the movement of the workpiece, resulting in low production efficiency. The guide rail type welding robot expands the working range of the robot by moving on the preset track, to a certain extent, solving the problem of long-weld-seam welding. However, the laying cost of the guide rail is high and the flexibility is poor, which cannot meet the flexible deployment requirements in different workstations or complex workshop environments, especially when the large steel structural member itself cannot be moved, its application is greatly limited.

[0004] In recent years, as a new scheme, the wheeled mobile welding platform has gradually emerged. The wheeled mobile welding platform installs the mechanical arm on the movable chassis, which can theoretically realize flexible operation in a large range. However, the existing mobile welding platform generally has the following technical problems: In the wheeled mobile welding platform, the chassis and the mechanical arm usually adopt independent control systems, and there is a lack of collaborative control between them. The separated control architecture causes the mechanical arm to be unable to perceive and compensate the position deviation of the chassis in real time during the movement of the chassis, and the chassis is unable to coordinate the movement according to the working state of the mechanical arm. In the process of welding while walking, the movements of the two cannot be synchronized, resulting in poor stability of the welding gun pose and fluctuations in the welding trajectory. During the mobile welding process, the chassis will change its pose and produce position deviation due to factors such as uneven ground and dynamic load changes. The existing wheeled mobile welding platform lacks effective motion compensation, and the pose change of the chassis cannot be transmitted to the mechanical arm in real time, resulting in the pose of the end welding gun (TCP) deviating from the target trajectory due to the disturbance of the chassis. The deviation will be amplified during the long-distance welding process, which seriously affects the weld quality. The existing mobile welding platform is difficult to ensure the stability of the weld in the process of welding while walking, and cannot meet the strict requirements of the shipbuilding, heavy steel and other industries on the welding quality.

[0005] OBJECTIVE In view of the problems existing in the prior art, the present application provides a welding method and system for mobile chassis and mechanical arm cooperative control of a mobile welding platform, which can realize synchronous control of chassis movement and mechanical arm welding, guarantee weld stability and high precision in the process of walking and welding, and meet the needs of automatic welding of continuous long welds of large structural parts such as ships and heavy steel.

[0006] The technical scheme is as follows: a welding method for mobile chassis and mechanical arm cooperative control of a mobile welding platform, comprising the following steps: step 1: acquiring target weld path information to be welded and real-time pose information of the mobile chassis in a global coordinate system in real time; Step 2: establishing a unified system kinematics model of the chassis and the mechanical arm, and decomposing the target weld path into a chassis target trajectory of the mobile chassis and a mechanical arm target trajectory of the mechanical arm according to the unified system kinematics model; Step 3: controlling the mobile chassis to travel along the chassis target trajectory; Step 4: calculating compensation motion required to be executed by the mechanical arm according to the deviation between the real-time pose information of the mobile chassis and the chassis target trajectory, and combining the mechanical arm target trajectory to obtain the compensation motion executed by the mechanical arm.

[0007] Further, in step 1, the real-time acquisition of the target weld path information to be welded is specifically performed as follows: A line laser sensor is used to scan the weld to obtain weld feature points, and a curve fitting algorithm is used to generate target weld path information, wherein the target weld path information includes a weld curve; Further, in step 1, the real-time acquisition of the real-time pose information of the mobile chassis in the global coordinate system is specifically performed as follows: A laser radar is used to scan the global environment, and an extended Kalman filter is used to calculate the global real-time pose information of the mobile chassis.

[0008] Further, in step 2, the unified system kinematics model of the chassis and the mechanical arm is established, comprising the following steps: The mobile chassis and the mechanical arm are modeled as a unified system, and a system Jacobian matrix is established: wherein, is a chassis Jacobian matrix, is a mechanical arm Jacobian matrix, is a system Jacobian matrix; a system kinematics model is established: wherein, is the speed of the mechanical arm end welding gun, is a chassis joint speed vector, is a mechanical arm joint velocity vector.

[0009] Further, in step 2, the target weld path is decomposed into a chassis target trajectory for moving the chassis and a mechanical arm target trajectory for the mechanical arm, which is performed as follows: according to the weld curve and a custom weld gun pose path sampling and pose planning are performed to generate a continuous target weld pose sequence , According to the system kinematics model, the target weld path is decomposed into a chassis target trajectory for moving the chassis and a mechanical arm target trajectory for the mechanical arm, which is represented as: wherein is a target pose of the mechanical arm end weld gun, is a target weld pose, is a chassis real-time pose.

[0010] Further, the moving chassis is controlled to travel along the chassis target trajectory, which is performed as follows: The moving chassis real-time pose information is represented as The moving chassis velocity is represented as: wherein v is a linear velocity of the moving chassis, ω is an angular velocity of the moving chassis, is a heading angle of the chassis in the world coordinate system, , is an actual position of the moving chassis center in the world coordinate system x, y axes; The deviation between the moving chassis real-time pose information and the chassis target trajectory is calculated , which is represented as: wherein , is a coordinate of a current tracking point on the target trajectory in the world coordinate system x, y axes; The moving chassis is controlled using a PID control algorithm to adjust the moving chassis angular velocity to eliminate the deviation between the moving chassis real-time pose information and the chassis target trajectory , which is represented as: is a derivative of , a front view distance of the mobile chassis, a front view angle of the mobile chassis, is a proportional coefficient, is a differential coefficient.

[0011] Further, the compensation motion includes compensation for a target joint speed of the robot arm and compensation for a welding torch end pose.

[0012] Further, for the compensation for the target joint speed of the robot arm, the following is performed: According to a system kinematics model, a robot arm joint speed is solved by minimum norm optimization : wherein, is a pseudo-inverse matrix of a system Jacobian matrix , a chassis joint speed vector is obtained by a speed of the mobile chassis According to the following formula: = , indicates that the chassis speed is equal to a chassis Jacobian matrix * a chassis joint speed vector .

[0013] Further, for the compensation for the welding torch end pose, the following is performed: The robot arm performs welding torch end pose adjustment, denoted as: is a pose change of a welding torch end coordinate system TCP with the chassis rotation around the Z-axis, is a yaw angle change angle of the mobile chassis, is a welding torch end pose before compensation, is a welding torch end pose after compensation.

[0014] A welding system with mobile chassis and robot arm cooperative control, characterized in that it comprises: a mobile chassis module; a robot arm execution module installed on the mobile chassis, comprising a robot arm with multiple degrees of freedom, and a welding torch configured at the end of the robot arm; a multi-modal perception module configured to obtain target weld path information to be welded and real-time pose information of the mobile chassis in a global coordinate system in real time; a cooperative control module configured to perform the method as described above.

[0015] ​The application establishes a unified kinematic model of the mobile chassis and the mechanical arm of the mobile welding platform, controls the two as a unified system, fundamentally solves the motion decoupling problem of the two in the traditional control scheme, can realize the optimal distribution of the task between the chassis and the mechanical arm, realizes high-precision cooperative motion, proposes a real-time compensation mechanism based on the actual motion deviation of the chassis, the mechanical arm no longer passively executes the predetermined trajectory, but actively and quickly responds and offsets the positioning and attitude error of the chassis, so as to ensure that the welding gun end can always accurately aim at the weld, greatly improves the welding precision and stability in the dynamic environment, can realize accurate welding while walking, avoids the frequent start-stop of the traditional "walk-stop-weld" mode, the welding process is more continuous and smooth, can significantly improve the production efficiency, can also ensure the quality consistency of the whole weld of the long weld, and reduces the welding defects. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A step schematic diagram of a welding method for mobile chassis and mechanical arm cooperative control of a mobile welding platform in the embodiment; Figure 2 A composition block diagram of a welding system for mobile chassis and mechanical arm cooperative control of a mobile welding platform in the embodiment. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present application clearer, further detailed description will be made to the present application in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

[0018] See Figure 1 The welding method for mobile chassis and mechanical arm cooperative control of a mobile welding platform of the present application comprises the following steps: Step 1: Real-time acquisition of target weld path information to be welded and real-time pose information of the mobile chassis in the global coordinate system; Step 2: Establishing a unified system kinematic model of the chassis and the mechanical arm, decomposing the target weld path into a chassis target trajectory of the mobile chassis and a mechanical arm target trajectory of the mechanical arm according to the unified system kinematic model; Step 3: Controlling the mobile chassis to travel along the chassis target trajectory; Step 4: According to the deviation between the real-time pose information of the mobile chassis and the chassis target trajectory, combining the mechanical arm target trajectory to calculate the compensation motion required to be executed by the mechanical arm, and the mechanical arm executes the compensation motion.

[0019] In the embodiment, in step 1, the target weld path information to be welded is acquired in real time, which is specifically executed as follows: The linear laser sensor scans the weld area of the workpiece surface at a frequency of 50Hz-100Hz, the linear laser sensor obtains the cross-sectional profile point cloud of the weld, through analysis of the point cloud data, a series of discrete weld feature points are fitted into a smooth curve to obtain the weld curve .

[0020] In the embodiment, in step 1, the real-time pose information of the mobile chassis in the global coordinate system is obtained in real time, which is specifically implemented as follows: The workpiece and the surrounding environment are scanned by the laser radar, real-time point cloud is generated and matched with the pre-constructed global map to realize global positioning; at the same time, the angular velocity and acceleration data of the inertial measurement unit can be fused to correct the attitude drift and improve the dynamic performance of the pose estimation; in the embodiment, the extended Kalman filtering algorithm is used to fuse the positioning results of the laser radar and the measurement values of the inertial measurement unit to obtain the global real-time pose information of the chassis in the world coordinate system , , is the heading angle of the chassis in the world coordinate system, 、 is the actual position of the mobile chassis center in the x, y axes of the world coordinate system.

[0021] In the embodiment, the laser radar, the inertial measurement unit, the linear laser sensor and other sensors are combined, and the extended Kalman filtering algorithm is used to realize high-precision chassis positioning and weld identification. The multi-sensor fusion improves the robustness and reliability of the perception system. Even in the case of complex environment or single sensor failure, the system can still work normally. Compared with the existing technology which relies on mechanical roller limiting, the positioning method of the present application is more flexible and has a wider range of applications.

[0022] In step 2 of the embodiment, the mobile chassis and the robot arm are regarded as a unified robot system with redundant degrees of freedom, the end effector of the system is the welding gun, and the speed of the welding gun is contributed by the motion of the chassis and the motion of the robot arm. In the embodiment, the unified system kinematics model of the chassis and the robot arm is established, including: The mobile chassis and the robot arm are modeled as a unified system, and the system Jacobian matrix is established and expressed as: wherein, is the chassis Jacobian matrix, which describes the contribution of the motion of the chassis to the TCP speed of the welding gun, is the robot arm Jacobian matrix, which describes the influence of the joint motion of the robot arm on the end speed of the welding gun, is the system Jacobian matrix, The system kinematics model is established: wherein, is the speed of the welding torch at the end of the robot arm, is the chassis joint speed vector, is the robot arm joint speed vector. In the embodiment, the mobile chassis and the robot arm are modeled as a system, the system Jacobian matrix and the system kinematics model are established, and the motion coupling problem between the mobile chassis and the robot arm is theoretically solved. Compared with the existing technology of separate control of the chassis and the robot arm, the unified modeling method can realize the coordination of the motion of the two, avoid the motion incoordination and precision loss caused by separate control, and ensure the stability of the welding trajectory during the walking and welding process.

[0023] In step 2, after obtaining the system kinematics model, the path sampling and pose planning are performed according to the weld curve and the custom welding torch pose to generate a continuous target welding pose sequence composed of a series of discrete pose points; According to the system kinematics model, the target weld path is decomposed into a chassis target trajectory of the mobile chassis and a robot arm target trajectory of the robot arm. According to the curvature, length of the weld, and the moving ability of the chassis, a chassis target trajectory that the mobile chassis should follow is planned, the principle of which is to make the robot arm be in its optimal working interval as much as possible during subsequent task execution, and to avoid singular poses. The chassis target trajectory is roughly along the weld direction, but will be adjusted according to the curvature of the weld, for example, to slow down or adjust the pose at sharp turns; The robot arm target trajectory that the robot arm needs to reach can be obtained through coordinate transformation, and is expressed as: wherein, is the target pose of the welding torch at the end of the robot arm, is the weld target pose, is the real-time pose of the chassis.

[0024] In the embodiment, the robot arm is a 6-DOF structure installed on the mobile chassis, and the position of the welding torch at the end of the robot arm in the robot arm base coordinate system is: wherein is the forward kinematics function of the robot arm, and the joint variable is , is the 6 joint variables. In the embodiment, according to the unified system kinematics model, the welding task is reasonably decomposed into a chassis motion task and a robot arm motion task, so that the chassis is responsible for translational motion, and the robot arm is responsible for fine trajectory tracking and pose adjustment.

[0025] In this embodiment, in step 3, the mobile chassis performs path tracking based on the chassis target trajectory generated in the previous step and the real-time chassis pose obtained in step 1. In this embodiment, the mobile chassis is controlled to move along the chassis target trajectory generated in step 2, specifically as follows: Real-time pose information of mobile chassis Represented as The speed of moving the chassis Represented as: in v The linear velocity of the moving chassis. ω The angular velocity of the moving chassis, It is the chassis's heading angle in the world coordinate system. , This refers to the actual position of the center of the moving chassis on the x and y axes of the world coordinate system. Calculate the deviation between the real-time pose information of the mobile chassis and the target trajectory of the chassis. , is represented as: in, , The coordinates of the current tracking point on the target trajectory in the world coordinate system along the x and y axes; To eliminate this deviation, the embodiment employs a PID control algorithm to control the mobile chassis and adjust its angular velocity. To eliminate the deviation between the real-time pose information of the mobile chassis and the target trajectory of the chassis. , is represented as: for The derivative of The predicted distance for the mobile chassis used to calculate the target point. This is the front view of the mobile chassis. It is a proportionality coefficient. These are differential coefficients used to smooth the control response, allowing the chassis to smoothly return to its target trajectory. This is achieved by adjusting the angular velocity of the moving chassis. The mobile chassis can smoothly converge to the target trajectory. The chassis has a very short control cycle to ensure synchronization with the robotic arm control.

[0026] Due to uneven ground, slippery and other factors, the actual trajectory of the chassis will inevitably deviate from the target trajectory of the chassis. At this time, the robot arm can be instructed to make a compensation movement to offset the influence of the chassis deviation on the position and attitude of the welding gun end. In step 4, the embodiment calculates the compensation movement required to be executed by the robot arm according to the deviation between the real-time pose information of the moving chassis and the target trajectory of the chassis, combined with the target trajectory of the robot arm, and the robot arm executes the compensation movement, thereby accurately offsetting the influence of the chassis motion disturbance on the welding gun pose, ensuring that the welding gun always accurately tracks the target weld, and ensuring the stability and consistency of the welding quality.

[0027] The compensation movement in the embodiment includes compensation for the target joint speed of the robot arm and compensation for the end attitude of the welding gun.

[0028] Wherein, for the compensation of the target joint speed of the robot arm, the following is executed: According to the system kinematics model , the actual movement of the chassis has contributed part of the speed, and the remaining speed task is completed by the robot arm, and the joint speed of the robot arm satisfies .

[0029] In the embodiment, since the robot arm is six degrees of freedom, the least norm optimization method is used to solve, which can minimize the joint motion speed while meeting the end speed task, so that the motion is smoother and the energy consumption is lower.

[0030] In the embodiment, the joint speed of the robot arm is solved by least norm optimization: Wherein, is the pseudo-inverse matrix of the system Jacobian matrix , and the chassis joint speed vector is obtained by the speed of the moving chassis according to the following formula: = , indicating that the chassis speed is equal to the chassis Jacobian matrix * chassis joint speed vector ; Since is the measured value, the compensated joint speed of the robot arm required to be issued to the robot arm controller can be directly obtained therefrom, and in the embodiment, the calculated is a joint speed instruction containing a compensation amount, which can ensure that the motion deviation of the chassis is perfectly offset by the compensation movement of the robot arm, so that the synthesized welding gun end speed is always consistent with the target. For example, if the chassis deviates to the left from the trajectory, the calculated An additional motion component will be automatically included to move the robot arm to the right, so that the TCP of the welding torch still remains on the correct weld path.

[0031] In addition to the position deviation, the stability of the pose is also important. The heading angle of the chassis will also be disturbed, when a small change in the heading angle of the moving chassis occurs, for example, a slight yaw caused by uneven ground, if the robot arm does not make any adjustments, the pose of the welding torch will also be deflected in the global coordinate system, which may cause the welding angle to be incorrect.

[0032] In order to keep the pose of the welding torch stable in the global coordinate system, while also compensating for the pose of the welding torch end, the following is executed: The robot arm executes the welding torch end pose adjustment, denoted as: To express the pose change of the welding torch end coordinate system TCP with the chassis rotation around the Z-axis with a rotation matrix, is the matrix of the pose change that can be directly used for calculation, is the change angle of the heading angle of the moving chassis, is the welding torch end pose before compensation, is the welding torch end pose after compensation, by executing the pose adjustment, the robot arm can actively offset the influence of the chassis yaw, and always maintain the correct relative relationship between the pose of the welding torch and the weld.

[0033] The embodiment of the present application provides a welding system for collaborative control of a moving chassis and a robot arm, which mainly comprises a moving chassis module 100, a robot arm execution module 200, a multi-modal perception module 300 and a collaborative control module 400.

[0034] In the embodiment, the moving chassis module 100 can adopt a four-wheel differential drive or a Mecanum wheel omnidirectional drive structure, which can realize translation and rotation in the plane. The chassis is integrated with core sensors and controllers, for example, a laser radar (LiDAR) for global positioning, an inertial measurement unit (IMU) for pose measurement, an encoder for feedback wheel speed, and a high-performance industrial-grade main control board (such as NVIDIA Orin) for running core algorithms. Based on the wheeled mobile chassis, the system does not need to lay physical guide rails, and can be flexibly moved and deployed in the factory workshop, can adapt to large workpiece welding tasks of different sizes and different positions, and has strong scene adaptability.

[0035] In the embodiment, the mechanical arm execution module 200 includes a 6-DOF industrial robot mounted on the mobile chassis module 100, and the end effector of the robot is a welding torch. The robot is responsible for performing the tasks of welding trajectory tracking and pose adjustment while the chassis is moving.

[0036] In the embodiment, the multi-modal perception module 300 includes a line laser sensor for scanning the weld seam and a laser radar for environment perception. The line laser sensor is responsible for accurately extracting the geometric features of the weld seam, and the laser radar is responsible for building a global map and realizing real-time positioning of the chassis.

[0037] In the embodiment, the collaborative control module 400 is responsible for establishing a unified kinematic model, task decomposition, and generating collaborative control instructions for the mobile chassis and the mechanical arm according to real-time sensing information.

[0038] The system in the embodiment can decompose complex long-weld seam welding tasks into large-scale rough tracking of the chassis and small-range accurate compensation of the mechanical arm. The multi-modal perception module provides real-time feedback, the collaborative control module makes dynamic decisions, and the mobile chassis and the mechanical arm work closely as executors to achieve high-precision and high-stability continuous welding during movement.

[0039] In the embodiment of the present application, a computer readable storage medium is also provided, which stores a program, and the program is characterized in that: when the program is executed by a processor, the welding method for collaborative control of a mobile chassis and a mechanical arm of a mobile welding platform is realized.

[0040] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a computer device, or a computer program product. Therefore, the embodiments of the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0041] The embodiments of the present application are described with reference to flowcharts and / or block diagrams according to the method, computer device, or computer program product of the embodiments of the present application. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal equipment to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal equipment produce a device for implementing the functions specified in the flowcharts and / or block diagrams.

[0042] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing terminal device to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flow diagrams.

[0043] In the embodiments of the present application, a computer program product is also provided, comprising computer programs / instructions, characterized in that the computer programs / instructions, when executed by a processor, implement the steps of the above method.

[0044] In actual application, the above computer program product includes but is not limited to: smart phones, desktop computers, notebook computers, tablet computers, host computers and server platforms, etc., which are not specifically limited herein.

[0045] The above describes the application of the welding method, system, computer readable storage medium and computer program product for the mobile chassis of the mobile welding platform and the collaborative control of the mechanical arm in detail, the principle and implementation mode of the present application are described herein by using specific examples, and the above embodiment is only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as the limitation of the present application.

Claims

1. A welding method for a mobile welding platform, characterized in that, The method comprises the steps of: Step 1: Real-time acquisition of target weld path information to be welded and real-time pose information of a mobile chassis in a global coordinate system; Step 2: Establishment of a unified system kinematics model of the chassis and the robot arm, and decomposition of the target weld path into a chassis target trajectory of the mobile chassis and a robot arm target trajectory of the robot arm according to the unified system kinematics model; Step 3: Control of the mobile chassis to travel along the chassis target trajectory; Step 4: Calculation of compensation motion to be performed by the robot arm according to the deviation between the real-time pose information of the mobile chassis and the chassis target trajectory, in combination with the robot arm target trajectory, and execution of the compensation motion by the robot arm.

2. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 1, characterized in that: In step 1, the real-time acquisition of target weld path information to be welded is specifically performed as follows: A line laser sensor is used to scan a weld to acquire weld feature points, and a curve fitting algorithm is used to generate target weld path information, which includes a weld curve.

3. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 1, characterized in that: In step 1, the real-time acquisition of real-time pose information of the mobile chassis in the global coordinate system is specifically performed as follows: A laser radar is used to scan the global environment, and an extended Kalman filter is used to calculate the global real-time pose information of the mobile chassis.

4. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 1, characterized in that: In step 2, the establishment of the unified system kinematics model of the chassis and the robot arm comprises the following steps: The mobile chassis and the robot arm are modeled as a unified system, and a system Jacobian matrix is established: wherein, is the chassis Jacobian matrix, is the manipulator Jacobian matrix, is the system Jacobian matrix; The system kinematics model is established: wherein, is the speed of the welding torch at the end of the robot arm, is the chassis joint speed vector, is the robot joint speed vector.

5. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 4, characterized in that: In step 2, the decomposition of the target weld path into the chassis target trajectory of the mobile chassis and the robot arm target trajectory of the robot arm is specifically performed as follows: According to the weld seam curve and a custom weld gun pose path sampling and pose planning are performed to generate a continuous sequence of target welding poses , According to the system kinematics model, the target weld path is decomposed into the chassis target trajectory of the mobile chassis and the robot arm target trajectory of the robot arm, which is represented as: wherein, is a target pose of a welding torch at the end of a robot arm, is a target pose of a weld seam, is a real-time pose of a chassis.

6. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 5, characterized in that: The mobile chassis is controlled to travel along the chassis target trajectory, which is specifically performed as follows: Mobile chassis real-time pose information is represented as , the speed of the mobile chassis is represented as: wherein v is the linear velocity of the mobile chassis, ω is the angular velocity of the mobile chassis, is the heading angle of the chassis in the world coordinate system, , is the actual position of the mobile chassis center in the world coordinate system x, y axes; calculating a deviation between real-time pose information of the mobile chassis and a target trajectory of the chassis is expressed as: wherein, , are the coordinates of the current tracking point on the target trajectory in the world coordinate system x, y axes. The PID control algorithm is adopted to control the mobile chassis to adjust the angular velocity of the mobile chassis to eliminate the deviation between the real-time position information of the mobile chassis and the target trajectory of the chassis is expressed as: is a derivative of is a derivative of is a front view distance of the mobile chassis, is a front view angle of the mobile chassis, is a proportional coefficient, is a differential coefficient.

7. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 6, characterized in that: The compensation motion includes compensation for the robot arm target joint speed and compensation for the welding gun end pose.

8. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 7, characterized in that: For the compensation for the robot arm target joint speed, it is specifically performed as follows: According to a system kinematics model, joint speeds of the robot arm are solved by minimum norm optimization : wherein, is the pseudo-inverse of the system Jacobian matrix , the chassis joint velocity vector is the velocity of the chassis by moving the chassis is obtained as follows: = , represents the chassis velocity is equal to the chassis Jacobian matrix * the chassis joint velocity vector .

9. The welding method for the mobile chassis and the robot arm cooperative control of the mobile welding platform according to claim 7, characterized in that: For the compensation for the welding gun end pose, it is specifically performed as follows: The robot arm performs welding gun end pose adjustment, which is represented as: To represent the change of pose of the TCP of the welding torch with the chassis rotation with the rotation matrix around the Z axis To obtain the pose of the chassis periodically, To obtain the change of the yaw angle of the moving chassis periodically synchronized with the pose acquisition period, To obtain the pose of the welding torch before compensation, To obtain the pose of the welding torch after compensation.

10. A welding system with a mobile chassis and a coordinated control of a robot arm, characterized in that, It comprises: a mobile chassis module; a robot arm execution module installed on the mobile chassis, comprising a robot arm with multiple degrees of freedom, and a welding gun arranged at the end of the robot arm; a multi-modal perception module configured to acquire real-time target weld path information to be welded and real-time pose information of the mobile chassis in a global coordinate system; a collaborative control module configured to perform the method according to any one of claims 1 to 9.

11. A computer readable storage medium having stored thereon a program, the program comprising instructions which, when executed by a computer, cause the computer to carry out the method of any one of claims 1 to 10. The program is executed by the processor to implement the welding method for collaborative control of a mobile chassis and a robot arm of a mobile welding platform according to any one of claims 1 to 9.

12. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to implement the steps of the method according to any one of claims 1 to 9.

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