Tunnel type steel arch support three surface six arm welding robot and control system

Abstract

The present application relates to the technical field of welding robots, in particular to a tunnel type steel arch three-face six-arm welding robot and a control system, the control system comprises a tunnel type steel arch three-face six-arm welding robot and a control unit, the control unit comprises a coordinate reference construction module, a welding task generation module, a process accessibility acquisition module, a task binding module and a task execution module. The present application can realize the collaborative control of the three-face area identification of the steel arch, the welding task generation, the welding joint manipulator adaptation evaluation and the multi-arm task balanced distribution, and improve the welding positioning accuracy, task distribution rationality and operation stability of the tunnel type steel arch three-face six-arm welding robot in the multi-face welding seam scene.

Description

Technical Field

[0001] This invention relates to the field of welding robot technology, specifically to a three-sided, six-arm welding robot for tunnel-type steel arch frames and its control system. Background Technology

[0002] Tunnel steel arch frames are crucial supporting components in the initial support construction of tunnels, typically requiring welding of multiple parts, including the top, left, and right sides. With the development of automated welding equipment, using multi-arm welding robots to weld steel arch frames can improve welding efficiency and reduce the intensity of manual welding to some extent.

[0003] However, the welding areas of tunnel-type steel arch frames are usually distributed on different spatial surfaces, and the weld seams in different areas have different requirements in terms of position, welding torch approach direction, and posture. When performing multi-face welding, existing welding robots often focus on executing a single weld seam trajectory or assigning welding tasks according to a preset sequence, making it difficult to accurately distinguish the spatial relationship between weld seams in different areas. Especially in the boundary area between the top and side surfaces, problems such as inaccurate weld seam identification and unclear task boundaries are prone to occur.

[0004] Meanwhile, for welding robots with multiple articulated manipulators, the ability of different manipulators to reach the same weld seam, their posture adaptation ability, and their ability to adapt to the entry direction are not the same. If welding tasks are assigned solely based on fixed numbers, distance, or human experience, problems may arise where a manipulator can reach the weld seam but the welding torch posture does not meet the requirements, or the tasks of multiple manipulators are unevenly distributed, thus affecting the continuity of welding and the overall work efficiency.

[0005] Therefore, how to accurately organize the weld seams to be welded on different surfaces of the steel arch frame in the three-sided welding scenario of tunnel steel arch frame, and how to allocate and control the tasks by combining the actual operation adaptability of multiple welding joint manipulators, has become a technical problem that the control system of the three-sided six-arm welding robot for tunnel steel arch frame needs to solve. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a three-sided, six-arm welding robot and control system for tunnel steel arch frames. This system enables collaborative control of three-sided area recognition of the steel arch frame, welding task generation, welding joint manipulator adaptation evaluation, and balanced allocation of multi-arm tasks. This improves the welding positioning accuracy, task allocation rationality, and operational stability of the three-sided, six-arm welding robot for tunnel steel arch frames in multi-face weld scenarios.

[0007] The present invention adopts the following technical solution: a control system for a three-sided six-arm welding robot for a tunnel-type steel arch frame, comprising a three-sided six-arm welding robot for a tunnel-type steel arch frame and a control unit. The three-sided six-arm welding robot for a tunnel-type steel arch frame includes a mobile base, a welding joint manipulator, and a laser radar.

[0008] The control unit includes:

[0009] The coordinate reference construction module is used to acquire point cloud data of the steel arch frame surface, establish a unified three-sided task coordinate reference, and separate the top surface area, left side area and right side area of ​​the steel arch frame based on the unified three-sided task coordinate reference.

[0010] The welding task generation module, based on a unified three-sided task coordinate reference, reads the pre-established steel arch frame welding process data table, maps the weld design start point, weld path control point column and weld design end point to the top surface area, left side area and right side area, obtains the area affiliation, and generates welding task units.

[0011] The process accessibility acquisition module calculates the process accessibility of the welding joint robot relative to each welding task unit based on the spatial envelope region of the welding task unit and the welding joint robot.

[0012] The task binding module generates the binding relationship between welding task units and articulated robotic arms based on process reachability.

[0013] The task execution module balances the cumulative welding path length of each welding joint robot, determines the robot arm to be executed for welding, and generates the welding execution sequence of each welding task unit according to the welding sequence number in the steel arch frame welding process data table. It then controls the corresponding robot arm to complete the welding operation according to the welding execution sequence.

[0014] As a further description of the above technical solution: the method for establishing a unified three-dimensional task coordinate reference includes:

[0015] Control the lidar to collect point cloud data on the surface of the steel arch frame;

[0016] The direction perpendicular to the walking plane of the moving base is used to determine the vertical reference direction;

[0017] Project the point cloud data of the steel arch frame surface onto the walking plane of the mobile base, extract the direction with the maximum extension length from the projection point set, and determine the corresponding direction as the extension direction of the steel arch frame length. Use the extension direction of the steel arch frame length as the first task axis.

[0018] The vertical reference direction perpendicular to the moving base's travel plane is used as the third task axis. The second task axis is determined based on the first and third task axes, and a unified three-dimensional task coordinate reference composed of the first, second, and third task axes is established.

[0019] As a further description of the above technical solution: the method for separating the top, left, and right sides of the steel arch frame based on a unified three-dimensional task coordinate reference includes:

[0020] Under the unified three-dimensional task coordinate reference, local plane fitting is performed on each surface point in the point cloud data of the steel arch frame to obtain the local surface normal direction of the corresponding surface point.

[0021] The local surface normal direction is projected onto the second and third task axes respectively to obtain the width direction normal component and the vertical normal component;

[0022] When the vertical normal component of a surface point is greater than the threshold for determining the top surface normal, and the absolute value of the vertical normal component is greater than the absolute value of the width direction normal component, the corresponding surface point is marked as a candidate point for the top surface.

[0023] When the width direction normal component of a surface point is less than the left side normal determination threshold, and the absolute value of the width direction normal component is greater than the vertical normal component, the corresponding surface point is marked as a candidate point for the left side.

[0024] When the width direction normal component of a surface point is greater than the right side normal determination threshold, and the absolute value of the width direction normal component is greater than the vertical normal component, the corresponding surface point is marked as a right side candidate point.

[0025] Neighborhood continuity screening and connected component analysis are performed on the candidate points on the top, left, and right sides respectively. The connected component with the most points that extends continuously along the first task axis is determined as the top, left, and right side regions respectively.

[0026] As a further description of the above technical solution: the method for obtaining the region affiliation includes:

[0027] The weld design start point, weld path control point column and weld design end point in the welding process data table are converted to a unified three-dimensional task coordinate reference to obtain the weld design path;

[0028] Based on the shortest distance from each path point on the weld design path to the fitted surface of each area point cloud, the path points are projected onto the surface of the area with the smallest distance to obtain the actual weld path and determine the weld area affiliation.

[0029] As a further description of the above technical solution: the method for generating welding task units includes:

[0030] Multiple spatial interpolation points are generated along the actual weld path according to the preset welding interpolation interval. These multiple spatial interpolation points are arranged sequentially according to the weld extension direction to form a weld centerline point array.

[0031] Obtain the local surface normal of the region where each spatial interpolation point is located, and use the corresponding local surface normal as the welding normal direction of the corresponding spatial interpolation point, thereby forming a welding normal point sequence that corresponds one-to-one with the weld centerline point sequence.

[0032] By reversing the direction of the outer side of the area to which the weld belongs, the approach direction of the welding gun can be obtained.

[0033] Determine the in-plane inclined reference direction based on the area to which the weld belongs;

[0034] Read the allowable range of welding torch tilt angle corresponding to the welding task unit from the welding process data table of the steel arch frame, and take the midpoint between the upper limit of the allowable range of welding torch tilt angle and the lower limit of the allowable range of welding torch tilt angle as the target value of welding torch tilt angle;

[0035] The welding torch axis direction vector is obtained based on the welding torch approach direction, the in-plane tilt reference direction, and the target value of the welding torch tilt angle.

[0036] Each weld seam and its corresponding weld centerline point sequence, welding normal point sequence, area affiliation, welding torch approach direction, and welding torch axis direction vector are constructed into a welding task unit, resulting in multiple welding task units.

[0037] As a further description of the above technical solution: the method for obtaining the process reachability includes:

[0038] For the a-th joint manipulator and the b-th welding task unit, the weld centerline point array of the b-th welding task unit is matched with the reachable space range of the end tool center point of the a-th joint manipulator to determine the space reachability.

[0039] Match the welding torch axis direction vector point column of the b-th welding task unit with the adjustable attitude range of the welding torch axis to determine the welding torch attitude capability.

[0040] Match the welding torch approach direction point list of the b-th welding task unit with the allowable range of the end approach direction to determine the cross-face entry capability. The allowable range of the end approach direction is stored in correspondence with the range of the end tool center point and is represented by an approach direction cone. The approach direction cone includes the approach center direction and the maximum allowable entry deflection angle.

[0041] When all of the above capabilities are met, the process reachability is calculated based on the position reachability margin, attitude margin, and cross-plane entry margin.

[0042] As a further description of the above technical solution: the method for generating binding relationships based on the process reachability includes:

[0043] For any welding task unit, when the process accessibility of a certain joint robot relative to the corresponding welding task unit is not lower than the preset accessibility threshold, the joint robot is written into the candidate execution arm set of the corresponding welding task unit.

[0044] After the candidate actuator set is generated, the articulated manipulators in the candidate actuator set are sorted from high to low according to the process accessibility. The articulated manipulator ranked first is determined as the main actuator of the corresponding welding task unit, and the articulated manipulator ranked second is determined as the backup actuator.

[0045] As a further description of the above technical solution: the method for determining the welding robotic arm includes:

[0046] First, lock each welding task unit to its corresponding main actuator arm and then calculate the cumulative welding path length of each welding joint manipulator.

[0047] When the cumulative welding path length of any welding joint robot exceeds the preset single-arm welding path length threshold, the welding joint robot is marked as a path load overload robot, and welding task units with spare execution arms are selected from its locked welding task units to form a transferable task set.

[0048] Calculate the difference between the process reachability of the main actuator arm and the process reachability of the backup actuator arm for each welding task unit in the transferable task set, and transfer the corresponding welding task unit from the original main actuator arm to the backup actuator arm in order of increasing difference. Update the cumulative welding path length of the relevant welding joint manipulator until the cumulative welding path length of the manipulator with path load exceeds the limit is less than or equal to the preset single-arm welding path length threshold, and obtain the execution welding manipulator for each welding task unit.

[0049] As a further description of the above technical solution: the method for generating the welding execution sequence of each welding task unit includes:

[0050] According to the welding sequence number in the steel arch frame welding process data table, the welding sequence number is mapped to all welding task units to obtain the welding sequence of all welding task units. The corresponding welding robotic arms are then controlled sequentially to perform welding processing.

[0051] A three-sided, six-arm welding robot for tunnel-type steel arch frames, comprising:

[0052] The mobile base has omnidirectional steering wheels at its bottom;

[0053] The robot body is rotatably connected to a mobile base via a turntable.

[0054] The articulated robotic arms consist of six in total, divided into two groups of three, symmetrically arranged on the outer wall of the robot body.

[0055] An end effector is provided at the end of the articulated manipulator, and the end effector is used to perform welding operations;

[0056] A lidar is located at the top center of the robot body.

[0057] As a further description of the above technical solution: the articulated manipulator consists of a first rotary joint, a rotary short arm, a second rotary joint, a rotary forearm, a third rotary joint, and an end effector seat;

[0058] The first rotary joint is fixed to the robot body. The rotary short arm is rotatably connected to the first rotary joint. The second rotary joint is rotatably connected to the rotary short arm. The rotary forearm is rotatably connected to the second rotary joint. The third rotary joint is rotatably connected to the rotary forearm. The end effector mount is rotatably connected to the third rotary joint.

[0059] As a further description of the above technical solution: the end effector includes:

[0060] The detection device is fixed to the end effector mount;

[0061] A welding mechanism, comprising a welding torch and a welding torch mounting base, wherein the welding torch mounting base is bolted to an end effector base and the welding torch is mounted on the welding torch mounting base;

[0062] The pickup and placement mechanism includes an electromagnet, an electromagnet mounting base, and a right-angle adapter plate. The right-angle adapter plate is fixedly connected to the end effector base. The electromagnet mounting base is bolted to the right-angle adapter plate, and the electromagnet is fixed on the electromagnet mounting base.

[0063] A dust collection hood is mounted and fixed on the end effector base.

[0064] The beneficial effects of this application are as follows:

[0065] This invention divides the point cloud on the surface of the steel arch frame into a surface region and maps the weld design path in the welding process data table to the corresponding surface region. This enables the generation of welding task units with surface region affiliation, weld centerline, welding normal, welding torch approach direction, and welding torch axis direction vector. This ensures that each weld to be welded forms a clear task boundary, reducing the risk of unclear weld affiliation in the boundary area, duplicate task generation, or task omission.

[0066] Secondly, in the process of assigning welding tasks, it is not only determined whether the welding joint robot can reach the weld position, but also the process accessibility is calculated by combining the obtained position accessibility margin, posture margin and cross-face entry margin. This allows the welding tasks to be preferentially assigned to welding joint robots that meet the requirements of spatial accessibility, posture control and entry direction, avoiding the problem of unqualified welding gun posture and limited approach path caused by assigning tasks based solely on distance or fixed number.

[0067] Furthermore, by determining the main and backup actuators for each welding task unit and making balanced adjustments based on the cumulative welding path length of each welding joint robot, it is possible to reduce the situation where a single welding joint robot bears too many tasks while ensuring the feasibility of the welding task. This makes the workload of multiple welding joint robots more balanced, improving the continuity and overall efficiency of three-sided six-arm collaborative welding. Attached Figure Description

[0068] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0069] Figure 1 This is a schematic diagram of the structure of a tunnel-type steel arch frame three-sided six-arm welding robot provided in Embodiment 1 of the present invention. Figure 1 ;

[0070] Figure 2 This is a schematic diagram of the structure of a tunnel-type steel arch frame three-sided six-arm welding robot provided in Embodiment 1 of the present invention. Figure 2 ;

[0071] Figure 3 This is a module connection diagram of a three-sided, six-arm welding robot control system for a tunnel-type steel arch frame provided in Embodiment 2 of the present invention;

[0072] Figure 4 This is a flowchart of a method for establishing a unified three-dimensional task coordinate reference provided in Embodiment 2 of the present invention.

[0073] Reference numerals: 1. Movable base; 2. Robot body; 3. First rotary joint; 4. Rotary short arm; 5. Second rotary joint; 6. Rotary forearm; 7. Third rotary joint; 8. End effector mount; 10. Right-angle adapter plate; 11. Electromagnet mounting base; 12. Electromagnet; 13. Welding torch holder; 14. Welding torch; 15. Dust hood; 16. LiDAR; 17. Turntable; 18. Omnidirectional steering wheel; 19. Detection device. Detailed Implementation

[0074] To make the technical means, creative features, objectives, and effects of this invention readily understandable, the invention is further described below with reference to specific illustrations. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0075] Example 1:

[0076] Please see Figures 1-2 This invention provides a technical solution: a three-sided, six-arm welding robot for tunnel-type steel arch frames, comprising:

[0077] The mobile base 1 has a universal travel steering wheel 18 at its bottom. Specifically, the universal travel steering wheel 18 is used to drive the welding robot to move within the construction site and can adjust the overall position and orientation of the robot. By setting the universal travel steering wheel 18, the arrangement flexibility of the welding robot relative to the steel arch frame can be improved, enabling the robot to quickly align itself according to the position changes of the steel arch frame, reducing manual handling and repetitive positioning work.

[0078] The robot body 2 is rotatably connected to the mobile base 1 via a turntable 17. By setting the turntable 17, the working angles of the robot body 2 and the six joint manipulators can be adjusted a second time after the position of the mobile base 1 is basically determined, thereby improving the robot's adaptability to different welding surfaces of the steel arch frame and avoiding positioning errors caused by frequent movement of the whole machine.

[0079] There are six articulated manipulators in total, divided into two groups of three, symmetrically arranged on the outer wall of the robot body 2. Specifically, through the symmetrical arrangement of three articulated manipulators in two groups, the welding robot can simultaneously cover multiple welding areas such as the top, left and right sides of the steel arch frame, adapting to the needs of three-sided welding operations.

[0080] An end effector is located at the end of the articulated robot and is used to perform welding operations.

[0081] A lidar unit 16 is positioned at the top center of the robot body 2. Specifically, the lidar unit 16 is located at the top center of the robot body 2 and is used to collect surface point cloud data of the steel arch frame. Because the lidar unit 16 is located at the top center of the robot body 2, its scanning field of view can cover the main surface area of ​​the steel arch frame, which is beneficial for obtaining the overall contour information of the top, left, and right sides of the steel arch frame. Through the point cloud data acquired by the lidar unit 16, the control system can establish the spatial positional relationship of the steel arch frame, identify the area to be welded, and provide a data foundation for subsequent welding task generation and robot path planning.

[0082] The articulated manipulator consists of a first rotary joint 3, a rotary short arm 4, a second rotary joint 5, a rotary forearm 6, a third rotary joint 7, and an end effector mount 8.

[0083] The first rotary joint 3 is fixed to the robot body 2. The rotary short arm 4 is rotaryly connected to the first rotary joint 3. The second rotary joint 5 is rotaryly connected to the rotary short arm 4. The rotary forearm 6 is rotaryly connected to the second rotary joint 5. The third rotary joint 7 is rotaryly connected to the rotary forearm 6. The end effector seat 8 is rotaryly connected to the third rotary joint 7.

[0084] End effectors include:

[0085] The detection device 19 is fixed to the end effector base 8. The detection device 19 is a camera used to acquire images and perform detection.

[0086] The welding mechanism includes a welding torch 14 and a welding torch mounting base 13. The welding torch mounting base 13 is bolted to the end effector seat 8, and the welding torch 14 is mounted on the welding torch mounting base 13.

[0087] The pick-and-place mechanism includes an electromagnet 12, an electromagnet mounting base 11, and a right-angle adapter plate 10. The right-angle adapter plate 10 is fixedly connected to the end effector seat 8. The electromagnet mounting base 11 is bolted to the right-angle adapter plate 10, and the electromagnet 12 is fixed to the electromagnet mounting base 11.

[0088] The dust hood 15 is mounted and fixed on the end effector seat 8.

[0089] Example 2:

[0090] Please see Figures 1-4 The present invention provides a technical solution: a control system for a tunnel-type steel arch three-sided six-arm welding robot, including a tunnel-type steel arch three-sided six-arm welding robot and a control unit. The tunnel-type steel arch three-sided six-arm welding robot includes a mobile base 1, a welding joint manipulator and a lidar 16.

[0091] The control unit includes:

[0092] The coordinate reference construction module is used to acquire point cloud data of the steel arch frame surface, establish a unified three-sided task coordinate reference, and separate the top surface area, left side area and right side area of ​​the steel arch frame based on the unified three-sided task coordinate reference.

[0093] In one embodiment, a method for establishing a unified three-dimensional task coordinate reference includes:

[0094] Control the lidar 16 to collect point cloud data on the surface of the steel arch frame.

[0095] The direction perpendicular to the traveling plane of the mobile base 1 is defined as the vertical reference direction.

[0096] The point cloud data of the steel arch frame surface is projected onto the walking plane of the mobile base 1. The direction with the maximum extension length is extracted from the projection point set, and the corresponding direction is determined as the extension direction of the steel arch frame. The direction with the maximum extension length is obtained by fitting the main direction of the projection point set, and the extension direction of the steel arch frame is used as the first task axis.

[0097] The vertical reference direction perpendicular to the moving base's travel plane is used as the third task axis. The second task axis is determined based on the first and third task axes, and a unified three-dimensional task coordinate reference composed of the first, second, and third task axes is established.

[0098] It should be noted that the second task axis is a direction that is perpendicular to both the first and third task axes. The positive direction of the second task axis is determined according to the right-hand coordinate system. After determining the first, second, and third task axes, the geometric center point of the point cloud data on the surface of the steel arch frame, which is the mean of the point cloud coordinates, is determined as the origin of the unified three-sided task coordinate reference. The first, second, and third task axes all pass through the origin of the coordinates, thereby establishing a unified three-sided task coordinate reference.

[0099] In one embodiment, the method for separating the top, left, and right sides of a steel arch frame based on a unified three-dimensional task coordinate reference includes:

[0100] Under a unified three-dimensional task coordinate reference, local plane fitting is performed on each surface point in the point cloud data of the steel arch frame to obtain the local surface normal direction of that surface point.

[0101] In one embodiment, the method for performing local plane fitting to obtain the local surface normal direction of a surface point includes: when performing local plane fitting on each surface point in the point cloud data of the steel arch frame surface under a unified three-plane task coordinate reference, taking any surface point as the center and obtaining a set of adjacent surface points with a preset neighborhood radius; when the number of points in the set of adjacent surface points is not less than the preset minimum fitting point number, calculating the geometric center point of the set of adjacent surface points, and constructing a local covariance matrix based on the offset vector of each adjacent surface point relative to the geometric center point; performing eigenvalue decomposition on the local covariance matrix, and taking the unit eigenvector corresponding to the smallest eigenvalue obtained by decomposition as the local surface normal direction;

[0102] The preset minimum number of fitting points is 6. This is based on the following principle: a local plane in three-dimensional space is determined by at least three non-collinear surface points, and the eigenvalue decomposition of the local covariance matrix has a stability requirement for the number of neighborhood points. Therefore, in addition to the minimum requirement of three points, redundant points are added, making 6 surface points the minimum number of points required for local plane fitting. When the number of points in the set of adjacent surface points is less than 6, it indicates that the number of effective points in the neighborhood of that surface point is insufficient, and the control system marks that surface point as a point whose normal direction is yet to be determined.

[0103] Then, the local surface normal direction is projected onto the second and third task axes respectively to obtain the width direction normal component and the vertical normal component.

[0104] When the vertical normal component of a surface point is greater than the threshold for determining the top surface normal, and the absolute value of the vertical normal component is greater than the absolute value of the width direction normal component, the corresponding surface point is marked as a candidate point for the top surface.

[0105] When the width direction normal component of a surface point is less than the left side normal determination threshold, and the absolute value of the width direction normal component is greater than the vertical normal component, the corresponding surface point is marked as a candidate point for the left side.

[0106] When the width direction normal component of a surface point is greater than the right side normal determination threshold, and the absolute value of the width direction normal component is greater than the vertical normal component, the corresponding surface point is marked as a candidate point for the right side.

[0107] Specifically, the threshold values ​​for determining the top surface normal, left side normal, and right side normal are determined based on the allowable tilt angle of the region. Specifically, the allowable tilt angle of the top surface is denoted as... The allowable tilt angle of the side is denoted as The threshold for determining the top surface normal is The threshold for determining the normal direction of the left side is - The threshold for determining the normal direction of the right side is .

[0108] Neighborhood continuity screening and connected component analysis are performed on the candidate points on the top, left, and right sides respectively. The connected component with the most points that extends continuously along the first task axis is determined as the top, left, and right side regions respectively.

[0109] In one embodiment, when performing neighborhood continuity filtering on candidate points on the top, left, and right sides, a set of adjacent surface points within a preset neighborhood radius is constructed with any candidate point as the center. The number of adjacent points in the corresponding set of adjacent surface points that have the same surface region label as the candidate point is counted and recorded as the number of similar adjacent points. The proportion of similar neighborhoods is calculated. When the number of similar adjacent points is not less than a preset continuous point count threshold and the proportion of similar neighborhoods is not less than a preset similar proportion threshold, the surface region label of the candidate point is retained; otherwise, the candidate point is marked as a pending point.

[0110] Specifically, the proportion of similar neighboring points refers to the total number of adjacent surface points with valid surface region labels in the statistical set of adjacent surface points, and the ratio of the number of similar adjacent points to the total number of valid adjacent points is used as the proportion of similar neighboring points for the candidate point. Among them, valid surface region labels refer to the top surface candidate point label, the left side candidate point label, or the right side candidate point label. Adjacent surface points that are labeled as undetermined normal points, noise points, or invalid points are not included in the calculation of the proportion of similar neighboring points.

[0111] When performing connected component analysis on the screened candidate points, the control system uses each candidate point as a graph node; when the spatial distance between two candidate points is not greater than the preset adjacency distance threshold, and the angle between the local surface normal directions of the two candidate points is not greater than the preset normal angle threshold, an adjacency edge is established between the two candidate points.

[0112] Subsequently, connected components in each candidate point set are searched based on adjacent edges, and the number of points and extension length in the first task axis direction of each connected component are calculated. Components that meet the preset threshold for the number of connected components and the preset threshold for the extension length are determined as valid connected components, and the valid connected component with the highest regional score in the corresponding surface region is determined as the top surface region, the left side surface region, or the right side surface region.

[0113] In one embodiment, the region score is obtained based on the number of points in the effective connected domain and the extension length in the first task axis direction.

[0114] Specifically, for each valid connected region in the same surface region, the control system first counts the number of candidate points contained in the valid connected region, and obtains the minimum and maximum coordinate values ​​of the valid connected region in the first task axis direction. The difference between the two is used as the extension length of the valid connected region in the first task axis direction.

[0115] The number of points in the effective connected components and the extension length along the first task axis are normalized separately. During normalization, the number of points in the current effective connected component is divided by the maximum number of points in all effective connected components within the same region to obtain the point score; the extension length along the first task axis of the current effective connected component is divided by the maximum extension length in all effective connected components within the same region to obtain the extension length score.

[0116] The region score of the effective connected region is obtained by weighted summing of the point count score and the extension length score. The point count score is used to characterize the point cloud scale of the connected region in the corresponding surface region, and the extension length score is used to characterize the degree of continuous coverage of the connected region along the length direction of the steel arch frame.

[0117] In one implementation, the weight of the point score is 0.4, and the weight of the extension length score is 0.6. Since the top, left, and right sides should typically extend continuously along the length of the steel arch, the weight of the extension length score is higher than that of the point score.

[0118] It should be noted that the aforementioned preset neighborhood radius, preset continuous point count threshold, preset similarity ratio threshold, preset adjacency distance threshold, preset normal angle threshold, preset connected component point count threshold, and preset extension length threshold are all determined based on the average point spacing of the effective surface point cloud of the steel arch frame, the similarity ratio of stable surface region samples, the fluctuation of the normal angle of stable plane samples, and the effective welding length of the steel arch frame. Specifically, the average point spacing d of the point cloud is first calculated. p And set the preset neighborhood radius to d p The preset adjacency distance threshold is set to d, which is 3 to 5 times the value of the threshold. p The threshold for the number of consecutive points is determined based on the median number of effective neighboring points in the neighborhood of the candidate point; the threshold for the proportion of similar points is determined based on the mean and standard deviation of the proportion of similar neighborhoods in stable surface region samples; the threshold for the included angle of normal points is determined based on the mean and standard deviation of the included angle of normal points in stable plane samples; the threshold for the number of connected components is determined based on the total number of points in the effective surface point cloud of the steel arch frame; and the threshold for the included extension length is determined based on the effective welding length of the steel arch frame.

[0119] The welding task generation module, based on a unified three-dimensional task coordinate reference, reads a pre-established steel arch frame welding process data table, maps the weld design start point, weld path control point column, and weld design end point onto the top, left, and right surface areas, obtains the area affiliation, and generates welding task units.

[0120] The steel arch frame welding process data sheet is generated based on the steel arch frame design drawings, welding process specifications, and manual teaching results. It is used to record the weld number, weld design start point, weld path control point list, weld design end point, weld length, weld type, weld leg size, allowable range of welding torch tilt angle, welding speed, welding current, welding voltage, and welding sequence number for each weld to be welded.

[0121] In one embodiment, the method for obtaining the region affiliation includes:

[0122] The weld design start point, weld path control point column and weld design end point in the welding process data table are converted to a unified three-dimensional task coordinate reference to obtain the weld design path; then, according to the shortest distance from each path point to each surface point cloud fitting surface on the weld design path, the path points are projected to the surface of the surface with the smallest distance to obtain the actual weld path and determine the weld surface region affiliation.

[0123] Methods for determining the weld area assignment include:

[0124] When the entire projected weld design path lies within the top surface region, the weld is assigned to the top surface region; when the entire projected weld design path lies within the left side surface region, the weld is assigned to the left side surface region; when the entire projected weld design path lies within the right side surface region, the weld is assigned to the right side surface region; when the weld design path crosses two adjacent surface regions, the weld is divided into two sub-welding task units using the boundary as the dividing point, and the surface region assignment of each sub-welding task unit is determined separately.

[0125] In one embodiment, a method for generating welding task units includes:

[0126] Multiple spatial interpolation points are generated along the actual weld path according to the preset welding interpolation spacing. These multiple spatial interpolation points are arranged sequentially according to the weld extension direction to form a weld centerline point array.

[0127] The preset welding interpolation interval is the difference in path length between two adjacent spatial interpolation points along the actual weld path; when the total length of the actual weld path cannot be divided by the preset welding interpolation interval, the last spatial interpolation point is fixed as the end point of the actual weld.

[0128] Obtain the local surface normal of the region where each spatial interpolation point is located, and use the local surface normal as the welding normal direction of the corresponding spatial interpolation point, thereby forming a welding normal point sequence that corresponds one-to-one with the weld centerline point sequence.

[0129] The direction vector of the welding torch axis is determined based on the area to which the weld belongs and the allowable range of the welding torch tilt angle.

[0130] Specifically, the direction of the outer side of the weld area is reversed to obtain the direction of the welding torch approach. The direction of the outer side of the top area is the positive direction of the third task axis, the direction of the outer side of the left side area is the negative direction of the second task axis, and the direction of the outer side of the right side area is the positive direction of the second task axis.

[0131] The in-plane tilt reference direction is determined based on the area to which the weld belongs. The in-plane tilt reference direction is used to define the deflection side of the welding torch axis relative to the welding torch approach direction.

[0132] In one embodiment, for the top surface weld, the left side weld, and the right side weld, the in-plane tilt reference direction is taken as the positive direction of the first task axis.

[0133] Read the allowable range of welding torch tilt angle corresponding to the welding task unit from the welding process data table of the steel arch frame, and take the midpoint between the upper limit and the lower limit of the allowable range of welding torch tilt angle as the target value of welding torch tilt angle; the welding torch tilt angle refers to the deflection angle of the welding torch axis direction vector relative to the welding torch approach direction.

[0134] Let B be the direction of approach of the welding torch, M be the in-plane tilt reference direction, and θ be the target value of the welding torch tilt angle. Generate the welding torch axis direction vector A according to A = cosθ·B + sinθ·M; where A represents the welding torch axis direction vector, cosθ·B represents the component of the welding torch axis direction vector in the direction of approach of the welding torch, and sinθ·M represents the component of the welding torch axis direction vector in the in-plane tilt reference direction.

[0135] Using the same welding torch approach direction and welding torch axis direction vector for all spatial interpolation points in the same welding task unit, a welding torch approach direction point sequence and a welding torch axis direction vector point sequence corresponding to the weld centerline point sequence are obtained.

[0136] Each weld seam and its corresponding weld centerline point sequence, welding normal point sequence, area affiliation, welding torch approach direction, and welding torch axis direction vector are constructed into a welding task unit, resulting in multiple welding task units.

[0137] The process accessibility acquisition module calculates the process accessibility of the welding joint robot relative to each welding task unit based on the spatial envelope region of the welding task unit and the welding joint robot.

[0138] Among them, the welding articulated robot is an articulated robot whose end effector is a welding torch.

[0139] In one embodiment, the method for obtaining process reachability includes:

[0140] For the a-th joint manipulator and the b-th welding task unit, the weld centerline point array of the b-th welding task unit is matched with the reachable space range of the end tool center point of the a-th joint manipulator to determine the space reachability.

[0141] In one embodiment, the method for determining spatial accessibility includes:

[0142] The reachability range of the end-effector center point of the a-th joint manipulator under a unified three-plane task coordinate reference is obtained. This reachability range is the spatial envelope area that the end-effector center point of the a-th joint manipulator can reach, and is predetermined by the manipulator's factory parameters, installation position calibration data, or no-load teaching data. Specifically, by controlling the a-th joint manipulator to perform discrete sampling within the allowable joint angle range, the spatial point set of the end-effector center point under the unified three-plane task coordinate reference is calculated, and a three-dimensional envelope surface is established for this spatial point set as the reachable spatial range of the end-effector center point.

[0143] Sequentially determine whether each spatial interpolation point in the b-th welding task unit is within the reach range of the end-effector center point; if all spatial interpolation points are within the reach range of the end-effector center point, then determine that the spatial reach capability of the a-th joint manipulator relative to the b-th welding task unit is satisfied.

[0144] If any spatial interpolation point is located outside the reach range of the end tool center point, then the spatial reach capability of the a-th joint manipulator relative to the b-th welding task unit is determined to be unsatisfactory.

[0145] Match the welding torch axis direction vector point column of the b-th welding task unit with the adjustable attitude range of the welding torch axis to determine the welding torch attitude capability.

[0146] In one embodiment, a method for determining the welding torch's posture capability includes:

[0147] The adjustable attitude range of the welding torch axis, pre-calibrated under a unified three-plane task coordinate reference, is read from the a-th joint robot arm. This adjustable attitude range corresponds to the range reachable by the end-effector center point and is stored, represented by an attitude cone. The attitude cone includes the attitude center direction. and maximum permissible deflection angle .

[0148] For any spatial interpolation point in the b-th welding task unit The control system reads the welding torch axis direction vector corresponding to the spatial interpolation point. ,calculate With respect to the direction of the attitude center The pose matching angle between ;

[0149] when When this happens, the spatial interpolation point is marked as an attitude-realizable point.

[0150] when When this happens, the spatial interpolation point is marked as an unachievable pose point.

[0151] If all spatial interpolation points are pose-realizable points, then the welding torch pose capability of the a-th joint manipulator relative to the b-th welding task unit is satisfied.

[0152] If any posture is unachievable, the welding torch posture capability is deemed unsatisfactory.

[0153] Match the welding torch approach direction point list of the b-th welding task unit with the allowable range of the end approach direction to determine the cross-face entry capability.

[0154] In one embodiment, the method for determining cross-surface access capability includes:

[0155] The permissible end-effector approach direction range of the a-th joint manipulator, pre-calibrated under a unified three-plane task coordinate reference, is read. This permissible end-effector approach direction range is stored corresponding to the reach range of the end-effector tool's center point and is represented by a proximity direction cone, which includes the approach center direction. and maximum allowable entry deflection angle .

[0156] For any spatial interpolation point in the b-th welding task unit Obtain the welding torch approach direction corresponding to the spatial interpolation point. ,calculate and near the center direction The entry matching angle between ;

[0157] when When this happens, the spatial interpolation point is marked as a near-realizable point.

[0158] when When this happens, the spatial interpolation point is marked as a point that is close to unrealizable.

[0159] If all spatial interpolation points are close to realizable points, then the cross-plane entry capability of the a-th joint manipulator relative to the b-th welding task unit is satisfied.

[0160] If there exists any point that is close to unrealizable, then the cross-face entry capability is determined to be unsatisfactory; when the cross-face entry capability is satisfied.

[0161] When all of the above capabilities are met, the process reachability is calculated based on the position reachability margin, attitude margin, and cross-plane entry margin.

[0162] In one embodiment, the method for obtaining the location reachability margin includes:

[0163] Calculate the shortest distance from each spatial interpolation point to the boundary of the range reachable by the end tool center point, and denote the shortest distance corresponding to the k-th spatial interpolation point as... .

[0164] The control system uses the minimum of the shortest distances corresponding to all spatial interpolation points as the position reachability margin. .

[0165] The calculation method is as follows: ;

[0166] in, This indicates the positional margin of the a-th joint manipulator relative to the b-th welding task unit; This represents the shortest distance from the k-th spatial interpolation point to the center point of the end tool reaching the boundary of the range, where n represents the total number of spatial interpolation points. The larger the value, the farther the weld centerline point array is from the boundary of the reach range of the a-th joint manipulator, and the higher the spatial execution stability.

[0167] In one embodiment, the method for obtaining the attitude margin includes:

[0168] For each spatial interpolation point, calculate the maximum allowable deflection angle. Subtract attitude matching angle Obtain the attitude margin of each spatial interpolation point .

[0169] The minimum value among all spatial interpolation points corresponding to the attitude margin is taken as the attitude margin. .

[0170] In one embodiment, the method for obtaining the cross-face entry margin includes:

[0171] Maximum allowable deflection angle Subtract the matching angle The cross-plane entry margin of the spatial interpolation point is obtained, and the minimum value among the cross-plane entry margins corresponding to all spatial interpolation points is taken as the cross-plane entry margin of the a-th joint manipulator relative to the b-th welding task unit. .

[0172] In one embodiment, the method for obtaining process accessibility includes normalizing the obtained positional accessibility margin, attitude margin, and cross-plane entry margin, and then performing a weighted summation to obtain the process accessibility.

[0173] Specifically, the position can be a normalized value. Calculate according to the following formula: ;

[0174] in, This indicates that the position is reachable from the normalized value; This indicates the reachable reference margin. The reachable reference margin is set based on the boundary safety distance of the reachable range of the center point of the end effector tool of the a-th joint robot.

[0175] pose normalization value Calculate according to the following formula: ;

[0176] in, This represents the pose normalization value; This indicates the attitude reference margin. The attitude reference margin is set based on the minimum and maximum allowable deflection angles within the adjustable attitude range of the welding torch axis.

[0177] Cross-face normalization value Calculate according to the following formula:

[0178] ;

[0179] in, This indicates that the value enters the normalized value across surfaces; This indicates the cross-face entry reference margin, which is set according to the minimum and maximum allowable entry deflection angle within the allowable range of the end approach direction.

[0180] Optionally, the formula for calculating the process reachability is: ;

[0181] Indicates the degree of process attainability. , and Here, are weighting coefficients, representing the position reachability weight, attitude weight, and cross-plane entry weight, respectively. + + =1.

[0182] In one implementation, =0.2, =0.4, =0.4; or determined based on the degree of influence of posture deviation, entry deviation and position deviation on the welding qualification rate in the standard weld trial run sample.

[0183] In one implementation, pose weights Greater than position reachable weight Cross-face weighting Greater than location reachability This ensures that the process accessibility primarily reflects the stability of the welding torch posture and the adaptability of cross-plane entry.

[0184] The task binding module is used to generate the binding relationship between welding task units and articulated robots based on process reachability.

[0185] In one embodiment, a method for generating binding relationships based on process reachability includes:

[0186] For any welding task unit, when the process accessibility of a certain jointed robot relative to the welding task unit is not lower than a preset accessibility threshold, the jointed robot is added to the candidate actuator set of the welding task unit.

[0187] When the process accessibility of a certain joint robot relative to the welding task unit is lower than a preset accessibility threshold, the joint robot is not allowed to execute the welding task unit.

[0188] The preset accessibility threshold is determined based on equipment debugging data. In one embodiment, the process accessibility of the welding joint robot when it completes all standard weld seam tasks under no-load trial operation is recorded, the average value and standard deviation of the process accessibility are calculated, and the value obtained by subtracting one standard deviation from the average value is used as the preset accessibility threshold.

[0189] After the candidate actuator set is generated, the articulated manipulators in the candidate actuator set are sorted from high to low according to the process accessibility. The articulated manipulator ranked first is determined as the main actuator of the corresponding welding task unit, and the articulated manipulator ranked second is determined as the backup actuator.

[0190] The task execution module, based on the main and backup execution arms corresponding to each welding task unit, balances the cumulative welding path length of each welding joint robot arm, determines the execution welding robot arm, and then generates the welding execution sequence of each welding task unit according to the welding sequence number in the steel arch frame welding process data table, and controls the corresponding execution welding robot arm to complete the welding operation according to the welding execution sequence.

[0191] In one embodiment, the method for determining the welding robotic arm includes:

[0192] Specifically, each welding task unit is initially locked to its corresponding main actuator arm, and the cumulative welding path length of each welding joint robot is calculated.

[0193] When the cumulative welding path length of any welding joint robot exceeds the preset single-arm welding path length threshold, the welding joint robot is marked as a path load overload robot, and welding task units with spare execution arms are selected from its locked welding task units to form a transferable task set.

[0194] The threshold for the single-arm welding path length is set as follows: The total welding path length is obtained by summing the lengths of the weld centerline points of all welding task units in the current batch; the number of welding joint robots currently in an available state and in the candidate execution arm set of at least one welding task unit is counted to obtain the number of allocable robots; the total welding path length is divided by the number of allocable robots to obtain the average welding path length per arm; the average welding path length per arm is multiplied by a preset equalization relaxation coefficient to obtain the preset single-arm welding path length threshold. The preset equalization relaxation coefficient is between 1.1 and 1.3.

[0195] It should be noted that the preset balance relaxation coefficient is determined based on the allowable path load differences between welding joint manipulators, the number of task switching times, and the stability of the backup actuator transfer. Specifically, if the preset balance relaxation coefficient is too small, the path load will be deemed excessive when the cumulative welding path length of a certain welding joint manipulator is slightly higher than the average welding path length of a single arm. This can easily lead to frequent transfers of welding tasks between the main actuator and the backup actuator, increasing the number of task switching times. If the preset balance relaxation coefficient is too large, a single welding joint manipulator will be allowed to handle too many welding paths, making it difficult to achieve the effect of multi-arm task balance. Therefore, the preset balance relaxation coefficient is set to 1.1 to 1.3, so that the cumulative welding path length allowed for a single welding joint manipulator is 10% to 30% higher than the average welding path length of a single arm, reducing frequent transfers while avoiding excessive concentration of load on a single arm.

[0196] Calculate the difference between the process reachability of the main actuator arm and the process reachability of the backup actuator arm for each welding task unit in the transferable task set, and transfer the corresponding welding task unit from the original main actuator arm to the backup actuator arm in order of increasing difference, and update the cumulative welding path length of the relevant welding joint manipulator until the cumulative welding path length of the manipulator with path load exceeds the limit is less than or equal to the preset single-arm welding path length threshold.

[0197] This yields the robotic arm for each welding task unit. Based on the welding sequence number in the steel arch frame welding process data table, the welding sequence number is mapped to all welding task units to obtain the welding sequence of all welding task units. The corresponding robotic arms are then controlled sequentially to perform the welding process.

[0198] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A control system for a three-sided, six-arm welding robot for tunnel-type steel arch frames, characterized in that, The invention includes a three-sided, six-arm welding robot for tunnel steel arches and a control unit. The three-sided, six-arm welding robot for tunnel steel arches includes a mobile base (1), a welding joint manipulator, and a laser radar (16). The control unit includes: The coordinate reference construction module is used to acquire point cloud data of the steel arch frame surface, establish a unified three-sided task coordinate reference, and separate the top surface area, left side area and right side area of ​​the steel arch frame based on the unified three-sided task coordinate reference. The welding task generation module, based on a unified three-sided task coordinate reference, reads the pre-established steel arch frame welding process data table, maps the weld design start point, weld path control point column and weld design end point to the top surface area, left side area and right side area, obtains the area affiliation, and generates welding task units. The process accessibility acquisition module calculates the process accessibility of the welding joint robot relative to each welding task unit based on the spatial envelope region of the welding task unit and the welding joint robot. The task binding module generates the binding relationship between welding task units and welding joint robots based on process reachability; The methods for establishing the binding relationship include: For any welding task unit, when the process reachability of a certain welding joint robot relative to the corresponding welding task unit is not lower than the preset reachability threshold, the welding joint robot is written into the candidate execution welding robot set of the corresponding welding task unit. After the candidate set of welding robotic arms is generated, the welding joint robotic arms in the candidate set are sorted from high to low according to the process accessibility. The welding joint robotic arm ranked first is determined as the welding robotic arm to be executed for the corresponding welding task unit, and the welding joint robotic arm ranked second is determined as the backup welding robotic arm. The task execution module balances the cumulative welding path length of each welding joint robot, determines the robot arm to be executed for welding, and generates the welding execution sequence of each welding task unit according to the welding sequence number in the steel arch frame welding process data table. It then controls the corresponding robot arm to complete the welding operation according to the welding execution sequence.

2. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 1, characterized in that, The method for establishing a unified three-dimensional task coordinate reference includes: Control the lidar (16) to collect point cloud data on the surface of the steel arch frame; The direction perpendicular to the walking plane of the movable base (1) is determined as the vertical reference direction; Project the point cloud data of the steel arch frame surface onto the walking plane of the mobile base (1), extract the direction with the maximum extension length from the projection point set, and determine the corresponding direction as the extension direction of the steel arch frame length. Use the extension direction of the steel arch frame length as the first task axis. The vertical reference direction perpendicular to the walking plane of the mobile base (1) is used as the third task axis. The second task axis is determined based on the first task axis and the third task axis, and a unified three-plane task coordinate reference composed of the first task axis, the second task axis and the third task axis is established.

3. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 2, characterized in that, The method for separating the top, left, and right sides of a steel arch frame based on a unified three-sided task coordinate datum includes: Under the unified three-dimensional task coordinate reference, local plane fitting is performed on each surface point in the point cloud data of the steel arch frame to obtain the local surface normal direction of the corresponding surface point. The local surface normal direction is projected onto the second and third task axes respectively to obtain the width direction normal component and the vertical normal component; When the vertical normal component of a surface point is greater than the threshold for determining the top surface normal, and the absolute value of the vertical normal component is greater than the absolute value of the width direction normal component, the corresponding surface point is marked as a candidate point for the top surface. When the width direction normal component of a surface point is less than the left side normal determination threshold, and the absolute value of the width direction normal component is greater than the vertical normal component, the corresponding surface point is marked as a candidate point for the left side. When the width direction normal component of a surface point is greater than the right side normal determination threshold, and the absolute value of the width direction normal component is greater than the vertical normal component, the corresponding surface point is marked as a right side candidate point. Neighborhood continuity screening and connected component analysis are performed on the candidate points on the top, left, and right sides respectively. The connected component with the most points that extends continuously along the first task axis is determined as the top, left, and right side regions respectively.

4. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 1, characterized in that, Methods for obtaining region affiliation include: The weld design start point, weld path control point column and weld design end point in the welding process data table are converted to a unified three-dimensional task coordinate reference to obtain the weld design path; Based on the shortest distance from each path point on the weld design path to the fitted surface of each area point cloud, the path points are projected onto the surface of the area with the smallest distance to obtain the actual weld path and determine the weld area affiliation.

5. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 4, characterized in that, Methods for generating welding task cells include: Multiple spatial interpolation points are generated along the actual weld path according to the preset welding interpolation interval. These multiple spatial interpolation points are arranged sequentially according to the weld extension direction to form a weld centerline point array. Obtain the local surface normal of the region where each spatial interpolation point is located, and use the corresponding local surface normal as the welding normal direction of the corresponding spatial interpolation point, thereby forming a welding normal point sequence that corresponds one-to-one with the weld centerline point sequence. By reversing the direction of the outer side of the area to which the weld belongs, the approach direction of the welding gun can be obtained. Determine the in-plane inclined reference direction based on the area to which the weld belongs; Read the allowable range of welding torch tilt angle corresponding to the welding task unit from the welding process data table of the steel arch frame, and take the midpoint between the upper limit of the allowable range of welding torch tilt angle and the lower limit of the allowable range of welding torch tilt angle as the target value of welding torch tilt angle; The welding torch axis direction vector is obtained based on the welding torch approach direction, the in-plane tilt reference direction, and the target value of the welding torch tilt angle. Each weld seam and its corresponding weld centerline point sequence, welding normal point sequence, area affiliation, welding torch approach direction, and welding torch axis direction vector are constructed into a welding task unit, resulting in multiple welding task units.

6. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 1, characterized in that, The method for obtaining the process reachability includes: For the a-th welding joint robot and the b-th welding task unit, the weld centerline point array of the b-th welding task unit is matched with the reachable space range of the end tool center point of the a-th welding joint robot to determine the space reachability. Match the welding torch axis direction vector point column of the b-th welding task unit with the adjustable attitude range of the welding torch axis to determine the welding torch attitude capability. Match the welding torch approach direction point list of the b-th welding task unit with the allowable range of the end approach direction to determine the cross-face entry capability. The allowable range of the end approach direction is stored in correspondence with the range of the end tool center point and is represented by an approach direction cone. The approach direction cone includes the approach center direction and the maximum allowable entry deflection angle. When all of the above capabilities are met, the process reachability is calculated based on the position reachability margin, attitude margin, and cross-plane entry margin.

7. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 1, characterized in that, The methods for determining the execution of the welding robotic arm include: First, lock each welding task unit to the corresponding welding robot arm and count the cumulative welding path length of each welding joint robot arm. When the cumulative welding path length of any welding joint robot exceeds the preset single-arm welding path length threshold, the welding joint robot is marked as a path load overload robot, and welding task units with backup welding robot arms are selected from the locked welding task units to form a transferable task set. Calculate the difference between the process reachability of the executing welding robot arm and the process reachability of the standby executing welding robot arm for each welding task unit in the transferable task set. Then, transfer the corresponding welding task unit from the original executing welding robot arm to the standby executing welding robot arm in order of increasing difference. Update the cumulative welding path length of the relevant welding joint robot arm until the cumulative welding path length of the robot arm with excessive path load is less than or equal to the preset single-arm welding path length threshold, and obtain the executing welding robot arm for each welding task unit.

8. The control system for a three-sided, six-arm welding robot for a tunnel-type steel arch frame according to claim 7, characterized in that, Methods for generating the welding execution sequence for each welding task unit include: According to the welding sequence number in the steel arch frame welding process data table, the welding sequence number is mapped to all welding task units to obtain the welding sequence of all welding task units. The corresponding welding robotic arms are then controlled sequentially to perform welding processing.

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