Movable rigid-flexible coupling welding robot system and method

Abstract

The invention belongs to the technical field of industrial robots, and discloses a movable rigid-flexible coupling welding robot system and method.The movable rigid-flexible coupling welding robot system comprises a movable base and a hydraulic lifting module which are arranged below a frame, and omni-directional movement and lifting of the system are achieved; a transverse moving module, a longitudinal moving module, a posture adjusting module and a rotating platform are arranged in the frame, and two-stage posture adjustment of the robot is conducted to adapt to geometry and welding seam characteristics of different workpieces; an outer vertical face welding auxiliary module is arranged on the side face of the frame, and robot overturning is achieved for outer vertical face welding; a welding robot device driven by a parallel flexible cable is arranged in the rigid-flexible coupling welding robot module, the posture of the welding gun module is adjusted, and all-directional and rapid welding of complex welding pieces is achieved. The problems that in the prior art, the working space of a welding robot is limited, and the welding efficiency is difficult to improve are solved, the large space coverage rate and flexibility are achieved, and various complex spot welding and arc welding operation tasks in the typical fields of automobiles, ship manufacturing, steel structures and the like can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of industrial robot technology, specifically relating to a mobile rigid-flexible coupling welding robot system and method. Background Technology

[0002] Welding is an industrial process that uses high-temperature melting of metal to join components. As one of the most important material forming and processing technologies in modern manufacturing, it is widely used in automobile, shipbuilding, and steel structure industries. Traditional manual welding is labor-intensive and involves harsh working environments. Furthermore, the welding process generates high-intensity arc light and harmful gases, making welding operations quite dangerous. Welding robots can replace traditional manual welding methods and offer advantages such as stable welding quality and high productivity, demonstrating broad application prospects.

[0003] Traditional welding robot bases are fixed to specific workstations, severely limiting their working range due to the robot's workspace. To increase the working range, one existing method is to mount the robot base on guide rails for movement. However, since the robot can only move along a single degree of freedom along the guide rail, its working range remains limited. Further, suspending the robot on a gantry allows for a larger working range through the gantry's lateral movement and the robot's longitudinal movement, enabling the welding of large and medium-sized parts and long weld seams, which has found widespread application in shipbuilding and other fields. However, the working range of existing welding robot systems is still limited by the mounting positions of guide rails, gantry structures, and the robot's own workspace, making it difficult to achieve full coverage of the work environment. Manual assistance is often required for placing or clamping the workpiece, limiting production efficiency. With the development of mobile robots and related positioning and navigation technologies, designing mobile welding robot bases can help improve the coverage of the work environment and increase production efficiency of welding robot systems.

[0004] Addressing the diverse, small-batch, and highly differentiated welding needs of heavy industries such as shipbuilding and steel structures, workpieces with non-standardized geometries and welds with complex features often involve complex welding processes and switching between multiple welding techniques. Traditional serial rigid robotic arms, characterized by high degrees of freedom and high absolute positioning accuracy, are widely used in welding operations. However, for welding tasks involving complex processes, the cumbersome reverse engineering process can negatively impact welding efficiency. Parallel robots, with their high repeatability, low inertia, and fast response speed, are particularly suitable for complex weld welding and switching between multiple welding processes. Furthermore, traditional parallel robots have limited workspace; rope-driven rigid-flexible coupling parallel robots offer advantages such as larger workspace, better dynamic performance, and lower required drive power, making them more suitable for high-intensity, complex welding operations. Specifically, robot pose adjustment devices can assist in adjusting the robot's pose to adapt to different workpiece geometries and weld characteristics, enabling efficient welding operations. Finally, designing an intelligent sensing system that combines multiple sensors helps to achieve automated welding operations for model-less prior parts in unstructured environments.

[0005] A search of existing publicly available technical documents revealed that Chinese invention patent application number CN202311755464.9 discloses a robotic arc welding workstation. This invention mounts a welding robot base at a fixed workstation and uses a displacement mechanism to clamp and fix the workpiece, adjust its position, and apply prestress. While this invention helps to further improve the automation level of arc welding, the robot's workspace is limited, and tasks such as workpiece clamping still require manual intervention, making it difficult to apply to welding operations of workpieces with highly varied dimensions.

[0006] Chinese invention patent application CN202411544891.7 discloses an automatic welding device and control method for multi-bracket joints. This invention mounts the welding assembly and joint clamping assembly on a lifting support bracket including an arc-shaped electrically controlled slide rail and a movable platform driven by a hydraulic cylinder. This allows for vertical lifting and rotational angle adjustment of the welding assembly and the joint clamping assembly. However, due to the limited degrees of freedom of the lifting support bracket and the limitations of the robot system's working range (considering the bracket's installation position, the size of the electrically controlled slide rail, and the hydraulic cylinder's stroke), it is more suitable for welding simple, small-to-medium-sized standardized weld seams in structured environments.

[0007] Chinese invention patent application CN202411261203.6 discloses a mobile omnidirectional welding robot. This invention mounts the welding robot above a vehicle frame, and the welding machine and control unit as a whole can achieve single-degree-of-freedom movement relative to the vehicle frame. Although this robot system increases the welding operation range to some extent, its workspace coverage is still limited due to the lack of height variation of the robot base. Summary of the Invention

[0008] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a mobile rigid-flexible coupling welding robot system and method. This welding robot system enables strong omnidirectional autonomous mobility, thereby increasing its coverage of the work environment. The rigid-flexible coupling welding robot achieves efficient welding of non-standard workpieces and complex weld seams, adapting to frequent switching between welding processes and improving the welding efficiency of the robot system. A robot posture adjustment device allows for posture adjustment while simultaneously increasing its workspace. Sensor modules enable positioning and navigation of the mobile base, automated control of the rigid-flexible coupling welding robot, and intelligent posture adjustment, providing a solution to the problems of limited workspace and difficulty in improving welding efficiency in autonomous intelligent welding.

[0009] The present invention is achieved through the following technical solution.

[0010] One aspect of the present invention provides a mobile rigid-flexible coupling welding robot system, comprising: The movable base module includes a frame module and wheel module that can move omnidirectionally within the welding work scene, which is used to achieve the coverage of the working scene of the welding robot system; The hydraulic lifting module includes a hydraulic cylinder and kinematic components mounted on a movable base module, used to realize the lifting of the welding robot system frame; The system framework, installed above the hydraulic lifting module, supports the robot's lateral movement module, robot's longitudinal movement module, exterior welding auxiliary module, robot posture adjustment module, robot rotating platform module, and rigid-flexible coupling welding robot module, thus constructing the overall system architecture. The rigid-flexible coupling welding robot module is a parallel flexible cable driven welding robot device used to adjust the position and posture of the welding torch module, enabling omnidirectional welding of complex workpieces. The robot longitudinal movement module, including a ball screw module and kinematic pair components, is used to adjust the longitudinal position and roll angle of the welding robot device. The robot lateral movement module is a moving platform consisting of a two-stage guide assembly and a drive unit, used to adjust the lateral position of the welding robot device located below it; The exterior welding auxiliary module is a deployable mechanism that rotates along the outside of the system frame. It uses at least two sets of electromagnetic clutch-based drive systems to achieve alternating transmission between the welding robot device and the lower side of the deployable mechanism along the robot's lateral movement module, thereby assisting in the exterior welding operation. The robot posture adjustment module, located below the robot's lateral movement module, is a 3-RPS parallel mechanism. It adjusts the two rotational and one translational amounts of the welding robot device by controlling the motion of the three motion chains. The robot rotation platform module is located between the robot posture adjustment module and the rigid-flexible coupling welding robot module, and is used to adjust the rotation of the rigid-flexible coupling welding robot module by a certain amount. The sensor system module is used for positioning the movable base module, as well as for monitoring the motion of the robot's lateral movement module, longitudinal movement module, facade welding auxiliary module, robot posture adjustment module, robot rotating platform module, and rigid-flexible coupling welding robot module.

[0011] Preferably, the system frame is a truss structure, which includes four symmetrically installed structural support components and transverse linkage components. A movable base module and a hydraulic lifting module are sequentially installed on the lower side of the structural support components. The robot's longitudinal movement module is vertically installed in the middle of the structural support components, and the robot's transverse movement module is located in the middle of the system frame and installed below the robot's longitudinal movement module. The exterior welding auxiliary module is hinged to the side of the structural support components and connected to the transverse linkage components via linkages.

[0012] Preferably, the robot's lateral movement module includes a primary platform panel connecting the ball screw module in the robot's longitudinal movement module. Below the primary platform panel are a lateral movement module drive component and a lateral movement module guide component. The lateral movement module drive component is a long-stroke ball screw module, and the lateral movement module guide component includes two levels of guide components. The primary guide assembly includes two first guide rails and a primary moving platform, which is fixedly mounted on the lead screw nut of the lateral moving module drive assembly. The secondary guide assembly includes two second guide rails located outside the first guide rail and a secondary platform panel. The secondary platform panel is connected to the second guide rails via second guide rail sliders and is connected to the lower surface of the primary moving platform to drive the secondary platform panel.

[0013] Preferably, the facade welding auxiliary module includes a second ball screw mounted on the transverse connecting rod assembly of the system frame, and a connecting rod hinged to the slider of the second ball screw module. The connecting rod is hinged to a deployable platform, which is hinged to the front of the structural support assembly via a pivot. Driven by the second ball screw module, the deployable platform can achieve a rotating motion around the pivot.

[0014] Preferably, two sets of tertiary platform panel drive modules and two sets of tertiary platform panel guide modules are provided on the lower surface of the secondary platform panel of the deployable platform and the robot lateral movement module. The tertiary platform panel is connected to the guide rail slider of the tertiary platform panel guide module and moves linearly with a single degree of freedom along the lower surface of the deployable platform and the secondary platform panel. The three-stage platform panel drive module connects the drive gear to the driven rack on the three-stage platform panel via a first stepper motor. The driven rack is alternately engaged with the drive gears of the two drive devices to transmit motion by the engagement or disengagement of the electromagnetic clutch assembly between the output shaft of the first stepper motor and the drive gear.

[0015] Preferably, the exterior welding auxiliary module also includes at least four sets of three-level platform panel limiting devices. The three-level platform panel limiting devices include a second-level platform panel installed on the robot's lateral movement module and a fifth guide groove on the edge of the unfoldable platform. A second stepper motor is fixedly connected to the fifth guide groove. The second stepper motor drives the gear to mesh with the rack inside the sliding limiting component, driving the sliding limiting component with baffle to move up and down along the fifth guide groove to limit the three-level platform panel.

[0016] Preferably, the robot posture adjustment module includes three motion chains and their motion pairs that connect to the three-level platform panel of the exterior welding auxiliary module. Each of the three motion chains is equipped with a folding electric cylinder to form a drive moving pair. The three motion chains are connected to a four-level moving platform, which is connected to the robot rotation platform module. The robot posture adjustment module has two rotational degrees of freedom and one translational degree of freedom.

[0017] Preferably, the robot rotating platform module includes a servo drive motor connected to a four-stage moving platform of the robot posture adjustment module. The output shaft of the servo drive motor is connected to a motor output shaft flange, and the motor output shaft flange passes through a thrust self-aligning roller bearing to connect to a five-stage rotating platform. The robot rotating platform module has one rotational degree of freedom.

[0018] Preferably, the rigid-flexible coupling welding robot module includes a stationary robot platform located below the five-stage rotating platform of the robot rotating platform module, and a moving robot platform parallel to the stationary robot platform. A flexible cable system connects the stationary robot platform and the moving robot platform to form a flexible motion chain. Nested radial extension modules and variable stiffness tensioning modules are provided between the stationary robot platform and the moving robot platform to form a rigid motion chain. A welding torch module is connected to the lower side of the moving robot platform. Each flexible cable system drives the flexible cable drum to rotate via a flexible cable drive servo motor, which in turn drives the parallel flexible cable branches that bypass the flexible cable drum to achieve contraction and release; The radial extension module drives the lead screw, which is fitted with a nut slider and a first sleeve, to rotate via a third stepper motor, thereby extending the rigid motion chain. The variable stiffness tensioning module achieves tensioning of the flexible cable connected to the robot's moving platform and stationary platform at the bottom of the variable stiffness tensioning module by extending and retracting the screw spring mechanism connected below the radial extension module. The stiffness of the rigid motion chain is adjusted by controlling the number of springs connected to the screw spring mechanism.

[0019] In another aspect, the present invention provides a welding method for a mobile rigid-flexible coupling welding robot of the aforementioned system, characterized in that it includes: S1, Welding robot system initialization, sensor system module testing, system calibration; S2, the movable base module uses the sensor system module to perform robot positioning and scene mapping, and plans the motion trajectory of the welding robot system; S3, the hydraulic lifting module drives the system frame to lift vertically, and the sensor system module on the system frame acquires local weldment point cloud data, and high-quality weldment point cloud is obtained through multi-view 3D reconstruction method; S4. For large and complex welded parts, repeat steps S2-S3 to register multiple local welded part point clouds until the welded part point cloud reconstruction is completed. S5 generates welds in a cloud-based welding manufacturing system based on the geometric features of the weldment. S6 groups and sorts multiple welds according to weld characteristics, workpiece geometry and task priority; separates welds involving facade welding from other welds, and separates welds whose length exceeds the workspace of the movable base module of the welding robot system in a stationary state from other welds. S7. Determine whether to use the exterior welding auxiliary module to drive the three-level platform panel and its lower robot posture adjustment module, robot rotation platform module and rigid-flexible coupling welding robot module to rotate 90°, depending on whether the weld group is an exterior welding task. S8 generates the welding torch trajectory based on the weld seam characteristics and the motion of the welding robot system. Combined with the scene map and the point cloud of the welded parts, the hydraulic lifting module drives the system frame to lift and lower to achieve obstacle avoidance. S9 uses the robot's longitudinal movement module and the robot's lateral movement module to perform preliminary pose adjustments for the robot's vertical lifting, horizontal movement, and rolling motion; The robot pose adjustment module and the robot rotation platform module are used to make fine adjustments to the robot's pose, including roll, pitch, yaw and vertical lifting. S10, based on the welding torch trajectory, the robot's longitudinal movement module, robot's lateral movement module, robot's posture adjustment module, robot's rotating platform module, and rigid-flexible coupling welding robot module work together to perform continuous welding operations; the robot's posture adjustment module and robot's rotating platform module cyclically perform posture adjustments. S11, for welds whose length exceeds the working space of the welding robot system base when stationary, the process needs to be repeated in segments: i. Steps S2-S3; ii. Steps S8-S10: Long weld seams are welded using the motion assistance of a movable base module; S12, repeat steps S8-S11 after each weld is completed, until a set of welds is completed; S13. Repeat steps S7-S11 after each set of welds is completed, until all welds are completed.

[0020] The present invention, by adopting the above technical solution, has the following beneficial effects: 1. This invention employs a rigid-flexible coupling welding robot driven by a parallel flexible cable. Compared to traditional serial welding robots, it reduces complex joint transmissions and offers advantages such as lightweight design, fast response, and low power consumption. The rigid-flexible coupling welding robot module uses a drum to synchronously wind up and unwind a parallel flexible cable, achieving automatic cable force distribution while reducing the number of motors and lowering the control complexity.

[0021] 2. The rigid-flexible coupling welding robot module of the present invention uses a radial extension module and a variable stiffness tensioning module to perform radial extension and contraction of the rigid branch and adjustment of the stiffness of the flexible cable. While achieving cable tensioning, it ensures dynamic matching between robot power consumption and end load, which can improve the welding efficiency of complex welds and is suitable for operation scenarios that require frequent switching of multiple welding processes.

[0022] 3. The robot's lateral and longitudinal movement modules in this invention constitute a primary control platform, used to initially adjust the robot's posture in the horizontal and vertical directions, significantly expanding the working range; the posture adjustment module and the rotation platform module constitute a secondary control platform, enabling fine adjustment of the three rotational amounts and one movement amount of the robot base; the two-level platforms work together to enable the rigid-flexible coupling welding robot to accurately adapt to the welding torch trajectory for posture adjustment.

[0023] 4. The facade welding auxiliary module in this invention is based on the on / off control principle of an electromagnetic clutch, combined with the alternating operation of two sets of drive devices, to realize the lateral movement and flipping motion of the welding robot and its posture adjustment device, thereby assisting in completing the facade welding task.

[0024] 5. The welding robot system in this invention adopts an omnidirectional movable base, which expands the system's operating range; by integrating a hydraulic lifting module, the system can achieve overall lifting, which enhances the system's obstacle avoidance capability while increasing the system's spatial operating range, effectively avoiding structural interference, and improving the system's versatility and robustness. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the external structure of the movable base; Figure 3 This is a schematic diagram of the internal structure of the movable base; Figure 4 This is an exploded view of the movable base wheel module and drive module; Figure 5 This is a schematic diagram of the hydraulic lifting module structure; Figure 6 This is a schematic diagram of the robot system framework; Figure 7 This is a schematic diagram of the robot's lateral and longitudinal movement modules; Figure 8 This is a partial schematic diagram of the hinge connection structure of the robot's lateral and longitudinal movement modules; Figure 9 This is a schematic diagram of the external facade welding auxiliary module structure; Figure 10 This is a schematic diagram of the structure of the exterior facade welding auxiliary module drive module; Figure 11 This is a schematic diagram of the limiting device structure for the welding auxiliary module on the exterior facade; Figure 12 This is a schematic diagram of the robot's posture adjustment module. Figure 13 This is an exploded view of the robot's rotating platform module; Figure 14 This is a schematic diagram of the overall structure of the rigid-flexible coupling welding robot module; Figure 15 This is a schematic diagram of the flexible cable drive system in the rigid-flexible coupling welding robot module; Figure 16 This is a schematic diagram of the flexible cable system structure in the rigid-flexible coupling welding robot module; Figure 17 This is a schematic diagram of the radial extension module structure in the rigid-flexible coupling welding robot module; Figure 18 This is a schematic diagram of the internal structure of the radial extension module; Figure 19 This is a schematic diagram of the variable stiffness tensioning module in the rigid-flexible coupling welding robot module. Figure 20 This is a flowchart of the operation method of a mobile rigid-flexible coupling welding robot system.

[0026] The reference numerals in the attached figures are as follows: 1. Movable base module; 101. First support panel; 102. Frame module; 102-1. Beam assembly; 102-2. Support column; 102-3. Second support panel; 102-4. Chassis assembly; 103. Wheel module; 103-1. Mecanum wheel side plate; 103-2. Roller shaft; 103-3. Roller; 103-4. Support shaft; 103-5. Mecanum wheel bracket; 104. Drive module; 104-1. First drive motor; 104-2. Transmission module side plate; 104-3. Drive gear; 104-4. Driven gear; 104-5. Output shaft; 104-6. Opposite side plate; 104-7. Transmission module housing; 105. Battery module; 2. Hydraulic lifting module; 201. Hydraulic cylinder base; 202. Hydraulic cylinder; 203. Output rod; 204. First hinge assembly; 205. Second hinge assembly; 206. Third hinge assembly; 3. System framework; 301. Structural support assembly; 302. Lateral linkage assembly; 303. Third ball screw module; 4. Robot lateral movement module; 401. Primary platform panel; 402. First support assembly; 403. Lateral movement module drive assembly; 403-1. Second drive motor; 403-2. First coupling; 403-3. Lead screw; 403-4. Lead screw nut; 404. Lateral movement module guide assembly; 404-1. First guide rail; 404-2. Moving platform; 404-3. Second guide rail; 404-4. Secondary platform panel; 404-5. Second guide rail slider; 5. Robot longitudinal movement module; 501. First ball screw module; 501-1. Ball screw slider; 6. Exterior facade welding auxiliary module; 601. Second ball screw module; 602. Deployable platform; 603. Connecting rod; 604. Third-level platform panel; 605. Three-level platform panel drive module; 605-1. Drive gear; 605-2. Driven rack; 605-3. First stepper motor; 605-4. Bearing; 605-5. Electromagnetic clutch motion input end; 605-6. Electromagnetic engagement component; 605-7. Spring; 605-8. Electromagnetic clutch motion output end; 606. Three-level platform panel guide module; 606-1. Third guide rail; 606-2. First limiting mechanism; 606-3. Fourth guide rail; 606-4. Second limiting mechanism; 607. Three-level platform panel limiting device; 607-1. Second stepper motor; 607-2. Gear; 607-3. Fifth guide groove; 607-4. Sliding limiting assembly; 607-5. Rack; 607-6. Baffle. 608. Shaft; 7. Robot posture adjustment module; 701. Four-stage moving platform; 702. Second support assembly; 703. Reversible electric cylinder; 704. Ball joint support assembly; 8. Robot rotating platform module; 801. Servo drive motor; 802. Motor output shaft flange; 803. Thrust self-aligning roller bearing; 804. First thrust bearing support; 805. Second thrust bearing support; 806. Five-stage rotary platform; 9. Rigid-flexible coupling welding robot module; 901. Robot static platform; 901-1. Through hole; 901-2. Fixing bolt assembly; 902. Robotic Motion Platform; 902-1. Flexible Cable Lifting Ring; 902-2. First Hooke Hinge Assembly; 903. Flexible cable drive system module; 903-1. Support base; 903-2. Flexible cable drive servo motor; 903-3. Synchronous belt pulley assembly; 903-4. Flexible cable drum; 904. Flexible cable system; 904-1. First guide wheel; 904-2. First guide wheel support; 904-3. Second guide wheel; 904-4. Second guide wheel support; 904-5. First flexible cable; 904-6. Second flexible cable; 905. Radial extension module; 905-1. Second Hooke hinge assembly; 905-2. Third stepper motor; 905-3. Flange; 905-4. Lead screw; 905-5. Second coupling; 905-6. Fifth guide rail; 905-7. First sleeve; 905-8. Stop; 905-9. Nut slider; 906. Variable stiffness tensioning module; 906-1. Second sleeve; 906-2. Outer ring of first sleeve; 906-3. Outer ring of second sleeve; 906-4. Threaded rod; 906-5. Spring; 906-6. Double-ended nut; 907. Welding torch module; 10. Sensor system module; 1001. Depth camera; 1002. LiDAR; 1003. Welding component scanning vision sensor; 1004. First laser rangefinder; 1005. Second laser rangefinder; 1006. First angle sensor; 1007. Third laser rangefinder; 1008. Second angle sensor; 1009. Fourth laser rangefinder; 1010. Third angle sensor; 1011. Cable displacement sensor. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0028] like Figure 1 As shown, this embodiment provides a mobile rigid-flexible coupling welding robot system, including a mobile base module 1, a hydraulic lifting module 2, a system frame 3, a robot lateral movement module 4, a robot longitudinal movement module 5, an exterior welding auxiliary module 6, a robot posture adjustment module 7, a robot rotation platform module 8, a rigid-flexible coupling welding robot module 9, and a sensor system module 10.

[0029] The movable base module 1 and the hydraulic lifting module 2 are sequentially installed on the lower side of the system frame 3 to enable omnidirectional movement and vertical lifting for obstacle avoidance of the entire system frame 3. The robot lateral movement module 4 is horizontally arranged inside the system frame 3, driving the robot to move laterally and adjusting the lateral position of the welding robot device located below it. The robot longitudinal movement module 5 is vertically installed inside the system frame 3, driving the robot to move vertically and adjusting the longitudinal position and roll angle of the welding robot device to adapt to different sized weldments. The robot lateral movement module 4 and the robot longitudinal movement module 5 are connected by a hinge mechanism. All of the above modules are used to achieve the initial pose adjustment of the rigid-flexible coupling welding robot module 9, so as to enable the robot system to avoid obstacles and ensure a large welding operation range and spatial coverage.

[0030] The exterior facade welding auxiliary module 6 is installed on the outer side of the middle part of the system frame 3. It includes a guide module connected to the lower side of the robot's lateral movement module 4 and a deployable module installed on the outer side of the middle part of the system frame 3. Through the guide module and the deployable module, the welding robot can achieve a 90° rotation to facilitate the robot's exterior facade welding task.

[0031] The robot posture adjustment module 7 and the robot rotation platform module 8 are sequentially installed below the robot lateral movement module 4. The robot posture adjustment module 7 has two rotational degrees of freedom and one translational degree of freedom; the robot rotation platform module 8 has one rotational degree of freedom. The robot lateral movement module 4, the robot longitudinal movement module 5, the robot posture adjustment module 7, and the robot rotation platform module 8 together form a two-stage posture adjustment device for the welding robot, enabling posture adjustment of the five degrees of freedom of the rigid-flexible coupling welding robot module 9, thereby increasing its working range and adapting to workpieces and welds with different geometric features.

[0032] The rigid-flexible coupling welding robot module 9 is installed on the lower side of the robot rotating platform module 8; it drives the lower moving platform 902 of the robot through the flexible cable drive system module 903, and further drives the welding gun module 907 connected to the lower side of the moving platform 902, so as to realize the all-round welding operation of complex weldments.

[0033] The sensor system module 10 is installed on the movable base module 1, the robot lateral movement module 4, the robot longitudinal movement module 5, the exterior welding auxiliary module 6, the robot posture adjustment module 7, the robot rotating platform module 8, and the rigid-flexible coupling welding robot module 9, respectively, and is used to position the movable base module 1 and monitor the motion of each module.

[0034] like Figure 2 As shown, the movable base module 1 of this embodiment includes four movable bases. Each movable base is an omnidirectional moving platform driven by four independent motors with Mecanum wheels. It includes a first support panel 101, a frame module 102, a wheel module 103, a drive module 104, a battery module 105, a depth camera 1001, and a lidar 1002.

[0035] The first support panel 101 is installed on the upper side of the frame module 102 and is used to connect the hydraulic lifting module 2 and install the depth camera 1001 and the lidar 1002; the wheel module 103 and the transmission module 104 are installed on the lower side of the frame module 102; and the battery module 105 is installed on the inner side of the middle part of the frame module 102.

[0036] like Figure 3As shown, the frame module 102 includes a beam assembly 102-1, support columns 102-2, a second support panel 102-3, and a chassis assembly 102-4. The beam assemblies 102-1 are located on both sides of the frame module 102 and are connected to the support columns 102-2 mounted on the inner side of the beam assembly 102-1 by bolts. The lower side of each support column 102-2 is connected to the second support panel 102-3. The chassis assembly 102-4 is fixedly mounted on the second support panel 102-3. Four drive modules 104 are mounted on the lower side of the second support panel 102-3 and located inside the chassis assembly 102-4. The drive modules 104 are installed correspondingly to the wheel modules 103. In addition, the battery module 105 is mounted on the second support panel 102-3 to supply power to the drive modules 104.

[0037] like Figure 4 As shown, the wheel module 103 and the drive module 104 are centrally symmetrically mounted. The wheel module 103 is a Mecanum wheel mechanism, which includes two Mecanum wheel side plates 103-1. Inside the two Mecanum wheel side plates 103-1, there are multiple roller shafts 103-2 mounted circumferentially. Each roller shaft 103-2 is concentrically mounted with a roller 103-3. In addition, inside the two Mecanum wheel side plates 103-1, there are multiple support shafts 103-4 mounted circumferentially. Furthermore, a Mecanum wheel bracket 103-5 is installed at the center of the inside of each side plate. This bracket is a cylinder with holes and keyways machined inside. The motor output shaft of the drive module 104 is concentric with the inner hole of the Mecanum wheel bracket 103-5 and connected by a flat key. The roller shafts 103-2, support shafts 103-4, and Mecanum wheel bracket 103-5 are all bolted to the Mecanum wheel side plates 103-1.

[0038] like Figure 4 As shown, the drive module 104 includes a first drive motor 104-1 and a transmission module. The first drive motor 104-1 is mounted on the transmission module side plate 104-2 to realize power input and is connected to the drive gear 104-3. The driven gear 104-4 is mounted on the output shaft 104-5, and the drive gear 104-3 meshes with the driven gear 104-4 for transmission. In addition, the transmission module side plate 104-2 and the opposite side plate 104-6 are mounted on both sides of the transmission module housing 104-7.

[0039] like Figure 5As shown, the hydraulic lifting module 2 in this embodiment includes four hydraulic cylinder systems and corresponding hinge assemblies. The hydraulic cylinder system includes a hydraulic cylinder base 201, a hydraulic cylinder 202, and a hydraulic cylinder output rod 203 mounted on the first support panel 101. The hinge module includes a first hinge assembly 204, a second hinge assembly 205, and a third hinge assembly 206 sequentially mounted on the hydraulic cylinder output rod 203. The second hinge assembly 205 and the first hinge assembly 204 form a first rotating joint, and the second hinge assembly 205 and the third hinge assembly 206 form a second rotating joint. In particular, the rotation axes of the first rotating joint and the second rotating joint are perpendicular. In addition, the third hinge assembly 206 is connected to the system frame 3 by bolts.

[0040] Therefore, the overall lifting and lowering movement of the system frame 3 can be achieved through the cooperation of four sets of hydraulic lifting modules 2, so as to avoid obstacles for the robot system according to the working environment and changes in the size of the welded parts, and prevent interference.

[0041] like Figure 6 As shown, the system frame 3 in this embodiment is a truss structure, which includes four symmetrically installed structural support components 301. The bottom of each structural support component 301 is connected to the third hinge component 206 of the hydraulic lifting module 2. The robot lateral movement module 4 and the robot longitudinal movement module 5 are mounted in the middle of the structural support component 301. The outer side of the middle of the structural support component 301 is connected to the exterior welding auxiliary module 6 through a hinge mechanism to achieve rotational connection relative to the system frame 3. The lowest point of the vertical movement of the exterior welding auxiliary module 6 and the robot lateral movement module 4 are on the same plane.

[0042] In addition, it also includes transverse link assemblies 302 at the top and middle of the structural support assembly 301 frame for holding the system frame 3; the structural support assembly 301 and the transverse link assembly 302 are connected by bolts to form the system frame 3 together.

[0043] like Figure 6 As shown, a third ball screw module 303 for driving the weldment scanning vision sensor 1003 is installed on the transverse link assembly 302 at the bottom; a first ball screw module 501 for driving the robot longitudinal movement module 5 is vertically installed on each structural support assembly 301 frame; and a second ball screw module 601 for driving the exterior welding auxiliary module 6 is installed on the transverse link assembly 302 installed in the middle of the upper side of the system frame 3.

[0044] like Figure 7 , Figure 8As shown, the robot's lateral movement module 4 in this embodiment includes a primary platform panel 401, a first support assembly 402, a lateral movement module drive assembly 403, and a lateral movement module guide assembly 404. Four first support assemblies 402 are mounted on the upper side of the primary platform panel 401; the four first support assemblies 402 correspond to the first ball screw module 501 in the robot's longitudinal movement module 5, and are connected to the ball screw slider 501-1 by bolts.

[0045] The lateral movement module drive assembly 403 is located on one side below the primary platform panel 401 and is arranged along the lower length of the primary platform panel 401. The lateral movement module drive assembly 403 is a long-stroke ball screw module, including a second drive motor 403-1, a first coupling 403-2, a lead screw 403-3, and a lead screw nut 403-4. The second drive motor 403-1 drives the lead screw 403-3 to rotate through the first coupling 403-2, and the lead screw nut 403-4 fitted on it converts the rotational motion of the lead screw 403-3 into its own translational motion.

[0046] To maximize the system's operating range, the primary platform panel 401 is designed to be relatively large, resulting in a correspondingly longer lead screw 403-3 in the lateral movement module drive assembly 403. To further improve the robot system's motion accuracy and stability, a two-stage guide assembly was designed. The primary guidance components include the primary platform panel 401 and the moving platform 404-2; The secondary guide assembly includes two secondary guide rails 404-3, a secondary platform panel 404-4, and a secondary guide rail slider 404-5.

[0047] The mobile platform 404-2 is fixedly mounted on the lead screw nut 403-4 by bolts or clips, realizing the driving of the lateral movement module drive assembly 403 to drive the mobile platform 404-2 in a single degree of freedom direction; further, the mobile platform 404-2 is fixed to four sliders mounted on two first guide rails 404-1 by bolts, realizing the guidance of its single degree of freedom direction; therefore, under the drive of the lead screw nut 403-4, the mobile platform 404-2 performs translational motion along the first guide rails 404-1.

[0048] The secondary guide assembly includes two second guide rails 404-3 located outside the lead screw 403-3. The two second guide rails 404-3 are installed on the lower side of the primary platform panel 401 and are parallel to the installation direction of the lead screw 403-3. Furthermore, the moving platform 404-2 and the secondary platform panel 404-4 are connected by bolts to drive the secondary platform panel 404-4. In particular, the secondary platform panel 404-4 is fixedly connected to the second guide rail slider 404-5 installed on the second guide rails 404-3 by bolts, so as to guide the movement of the secondary platform panel 404-4 by the second guide rails 404-3, thereby realizing the precise long-stroke relative movement between the primary platform panel 401 and the secondary platform panel 404-4.

[0049] Driven by the lateral movement module drive component 403, the secondary platform panel 404-4 moves in a single degree of freedom along the direction of the lateral movement module guide component 404; a first laser range sensor 1004 is installed on each side of the primary platform panel 401 to monitor the displacement of the secondary platform panel 404-4. like Figure 7 As shown, the robot longitudinal movement module 5 in this embodiment includes four first ball screw modules 501, whose installation positions within the frame are as follows: Figure 6 As shown; Figure 8 As shown, the ball screw slider 501-1 of the first ball screw module 501 is fixedly connected to the first support assembly 402, thereby forming a rotational connection between the robot longitudinal movement module 5 and the robot lateral movement module 4; four second laser rangefinders 1005 are respectively installed on the lateral link assembly 302 to monitor the displacement and tilt of the first-level platform panel 401.

[0050] For the movement of the four ball screw modules 501: the displacement of the two left screws is the same, denoted as displacement I, and the displacement of the two right screws is the same, denoted as displacement II; the rotation of the first-level platform panel 401, i.e., the rolling motion, is controlled by the relative difference between the two displacements, thereby realizing the initial control of the posture of the rigid-flexible coupling welding robot module 9.

[0051] Specifically, in this embodiment, a two-level robot pose adjustment control mechanism is defined, wherein the robot lateral movement module 4 and the robot longitudinal movement module 5 serve as the first-level robot pose adjustment device to realize the initial adjustment of the welding robot's posture, namely, horizontal movement, vertical lifting and rolling motion.

[0052] like Figure 9 , Figure 10 , Figure 11As shown, the exterior welding auxiliary module 6 in this embodiment includes a second ball screw module 601, a deployable platform 602, a connecting rod 603, a three-stage platform panel 604, a three-stage platform panel drive module 605, a three-stage platform panel guide module 606, a three-stage platform panel limiting device 607, and a rotating shaft 608. The second ball screw module 601, the connecting rod 603, and the deployable platform 602 form a crank-slider mechanism; wherein, as... Figure 9 As shown, the second ball screw module 601 is mounted on the transverse connecting rod assembly 302. The slider of the second ball screw module 601 is connected to the connecting rod 603 via a hinge. The connecting rod 603 is connected to the deployable platform 602 via a hinge. The deployable platform 602 is connected to the front support of the structural support assembly 301 via a rotating shaft 608 machined on its lower side. Therefore, under the drive of the second ball screw module 601, the deployable platform 602 can achieve a rotating motion around the rotating shaft 608 relative to the system frame 3. A first angle sensor module 1006 is installed at the hinge connection between the rotating shaft 608 and the front support of the structural support assembly 301 to monitor the rotation angle of the deployable platform 602.

[0053] Furthermore, the exterior welding auxiliary module 6 includes two sets of tertiary platform panel drive modules 605, which are fixedly installed at the center of the lower surface of the deployable platform 602 and the secondary platform panel 404-4, respectively. In addition, it includes two sets of tertiary platform panel guide modules 606, which are located on both sides of the lower surface of the deployable platform 602 and the secondary platform panel 404-4, respectively. Finally, four sets of tertiary platform panel limiting devices 607 are installed on one side of the deployable platform 602 and the secondary platform panel 404-4, and pass through their upper and lower surfaces, to limit the tertiary platform panel 604 that moves with a single degree of freedom on the lower side.

[0054] Specifically, the three-level platform panel drive module 605 includes a drive gear 605-1, a driven rack 605-2, and a first stepper motor 605-3. The driven rack 605-2 alternately meshes with the drive gears 605-1 of the two drive devices to achieve motion transmission. The drive gear 605-1 is mounted on the output shaft of the first stepper motor 605-3, and the driven rack 605-2 is mounted on the upper surface of the three-level platform panel 604 by bolts.

[0055] The three-level platform panel guide module 606 includes a third guide rail 606-1, a first limiting mechanism 606-2, a fourth guide rail 606-3, and a second limiting mechanism 606-4. The three-level platform panel 604 is mounted on a slider on either the third guide rail 606-1 or the fourth guide rail 606-3, enabling single-degree-of-freedom movement of the three-level platform panel 604 beneath the deployable platform 602 and the secondary platform panel 404-4, thereby ensuring the linear motion accuracy of the three-level platform panel 604.

[0056] In this embodiment, four sliders and driven racks 605-2 that are slidably connected to the third guide rail 606-1 or the fourth guide rail 606-3 are fixed on the upper side of the three-level platform panel 604 by bolts. Therefore, the movement of the three-level platform panel 604 is achieved by driving the driven racks 605-2 to make linear motion through the drive gear 605-1 installed on the first stepper motor 605-3.

[0057] In particular, such as Figure 9 As shown, in this embodiment, the movement of one side of the third-level platform panel 604 is locked by the first limiting mechanism 606-2 and the second limiting mechanism 606-4. The specific limiting relationship is as follows: if the third-level platform panel 604 is located below the second-level platform panel 404-4, the first limiting mechanism 606-2 restricts its rear movement degree of freedom; if the third-level platform panel 604 is located below the unfoldable platform 602, the second limiting mechanism 606-4 restricts its front movement degree of freedom.

[0058] The three-level platform panel driving module 605 in this embodiment includes two sets of driving devices, which are respectively installed on the lower side of the secondary platform panel 404-4 and the unfoldable platform 602, as shown in the following installation positions. Figure 9 As shown; specifically, such as Figure 9 , Figure 10 As shown, a first stepper motor 605-3 and a drive gear 605-1 are respectively installed at the center of the lower surface of the secondary platform panel 404-4 and the deployable platform 602. Bearings 605-4 are installed on the two shafts on the side of the drive gear 605-1. In particular, an electromagnetic clutch assembly is installed between the output shaft of the first stepper motor 605-3 and the drive gear 605-1, which includes an electromagnetic clutch motion input end 605-5, an electromagnetic attraction component 605-6, a spring plate 605-7, and an electromagnetic clutch motion output end 605-8; wherein, the electromagnetic clutch motion input end 605-5 is connected to the output shaft of the first stepper motor 605-3, and the electromagnetic clutch motion output end 605-8 is connected to the shaft of the drive gear 605-1.

[0059] Specifically, when the electromagnetic clutch assembly is energized, the electromagnetic engagement component 605-6 engages the motion input part 605-5 and the motion output part 605-8, realizing the motion transmission of the drive device; when the electromagnetic clutch assembly is de-energized, the spring plate 605-7 rebounds, and the motion input part 605-5 and the motion output part 605-8 are disconnected, cutting off the motion transmission of the drive device; therefore, through the two working modes of the electromagnetic clutch assembly—energized engagement and de-energized release—the alternating transmission of the first stepper motor 605-3 to the drive gear 605-1 is realized.

[0060] The following example demonstrates the workflow of moving the third-level platform panel 604 from the underside of the second-level platform panel 404-4 to the underside of the unfoldable platform 602: The electromagnetic clutch assembly in the tertiary platform panel drive module 605 below the secondary platform panel 404-4 engages. Driven by the first stepper motor 605-3 in the tertiary platform panel drive module 605 below the secondary platform panel 404-4, the tertiary platform panel 604 moves away from the first limiting mechanism 606-2 and along the third guide rail 606-1 located below the secondary platform panel 404-4. Further, the first two sliders on the upper side of the tertiary platform panel 604 are slidably connected to the fourth guide rail 606-3 below the deployable platform 602. At this time, the driven rack 605-2 meshes with the driving gear 60 in the tertiary platform panel drive module 605 below the deployable platform 602. 5-1, the electromagnetic clutch assembly in the lower drive device of the deployable platform 602 engages, and the electromagnetic clutch assembly in the lower drive device of the secondary platform panel 404-4 disengages, realizing the alternating transmission relationship of the drive device; finally, driven by the first stepper motor 605-3 in the lower drive device of the deployable platform 602, the tertiary platform panel 604 reaches the lower side of the deployable platform 602 and contacts the second limiting mechanism 606-4; in particular, during the movement of the tertiary platform panel 604, it is necessary to strictly control the coplanarity of the secondary platform panel 404-4 and the deployable platform 602, so as to ensure the alignment of the third guide rail 606-1 and the fourth guide rail 606-3 on their lower sides.

[0061] like Figure 9 , Figure 11 As shown, the exterior welding auxiliary module 6 of this embodiment includes four sets of three-level platform panel limiting devices 607, which include a second stepper motor 607-1, a gear 607-2, a fifth guide groove 607-3, a sliding limiting component 607-4, a rack 607-5, and a baffle 607-6. The fifth guide groove 607-3 is installed on the edges of the secondary platform panel 404-4 and the deployable platform 602, respectively. The sliding limiting component 607-4, fitted in the fifth guide groove 607-3, passes through the upper and lower surfaces of the secondary platform panel 404-4 and the deployable platform 602. The specific installation positions are as follows: Figure 9As shown; the second stepper motor 607-1 is installed on the side of the fifth guide groove 607-3, and the output shaft of the second stepper motor 607-1 passes through the reserved hole of the fifth guide groove 607-3 and is connected to the gear 607-2; the sliding limit assembly 607-4 is slidably installed inside the fifth guide groove 607-3, and the gear 607-2 meshes with the rack 607-5 installed inside the sliding limit assembly 607-4. A baffle 607-6 is machined on the lower side of the sliding limit assembly 607-4. The width of the baffle 607-6 is greater than that of the sliding limit assembly 607-4 and the lower end is machined with a bevel, which can better limit the position of the third-level platform panel 604 and facilitate locking; the third laser range sensor 1007 is installed on one side of the lower surface of the second-level platform panel 404-4 and the unfoldable platform 602 respectively to monitor the displacement of the third-level platform panel 604.

[0062] Furthermore, taking the process of the third-level platform panel 604 moving from the lower side of the second-level platform panel 404-4 to the lower side of the unfoldable platform 602 as an example, the limiting process of the third-level platform panel limiting device 607 is explained: When the third-level platform panel 604 is located below the second-level platform panel 404-4, the gear 607-2 installed on the output shaft of the second stepper motor 607-1 in the third-level platform panel limiting device 607 installed on one side of the second-level platform panel 404-4 drives the rack 607-5 inside the sliding limiting component 607-4 to move, thereby lowering the lower baffle 607-6 of the sliding limiting component 607-4. Then, the baffle 607-6 and the first limiting component 606-2 together complete the limiting of both sides of the third-level platform panel 604.

[0063] Furthermore, when the third-level platform panel 604 needs to enter the lower side of the deployable platform 602, firstly, the baffle 607-6 in the third-level platform panel limiting device 607 installed on the second-level platform panel 404-4 rises to release the third-level platform panel 604; finally, when the third-level platform panel 604 enters the lower side of the deployable platform 602, the process of the baffle 607-6 in the third-level platform panel limiting device 607 descending is repeated, so that the baffle 607-6 and the second limiting component 606-4 together limit the third-level platform panel 604.

[0064] To more clearly illustrate this embodiment, the complete workflow of the exterior facade welding auxiliary module 6 is briefly given: Driven by the robot's longitudinal movement module 5, the first-level platform panel 401 in the robot's lateral movement module 4 reaches its lowest point in the vertical direction and locks; driven by the robot's lateral movement module 4, the third-level platform panel 604 reaches the lateral center position of the system frame and locks; at this time, the third guide rail 606-1 and the fourth guide rail 606-3 are aligned; combined with the aforementioned partial workflow: under the alternating transmission of the two sets of third-level platform panel drive modules 605, the third-level platform panel 604 moves from the underside of the second-level platform panel 404-4 to the underside of the deployable platform 602; Specifically, during this process, the secondary platform panel 404-4 and the tertiary platform panel limiting device 607 on the underside of the deployable platform 602 work sequentially to release and lock the tertiary platform panel 604; finally, driven by the second ball screw module 601, the deployable platform 602 and the tertiary platform panel 604 achieve a 90° rotation; during this process, the robot posture adjustment module 7, the robot rotation platform module 8, and the rigid-flexible coupling welding robot module 9 installed on the underside of the tertiary platform panel 604 rotate simultaneously, thereby assisting the subsequent robot device to achieve the welding of the exterior facade.

[0065] like Figure 12 As shown, the robot posture adjustment module 7 in this embodiment is a 3-RPS parallel mechanism, which includes a static platform (i.e., the third-level platform panel 604 in the exterior welding auxiliary module 6), a fourth-level moving platform 701, and three motion chains. Specifically: a second support assembly 702, consisting of three motion chains arranged in an equilateral triangle on the underside of the static platform, forms a revolute joint; the fourth-stage moving platform 701 is an equilateral triangular panel, with a ball joint support assembly 704, consisting of three motion chains, mounted along the equilateral triangle on its upper side, forming a spherical joint; furthermore, a reciprocating electric cylinder 703 is mounted on each of the three motion chains, which can be considered as a driving prismatic joint; therefore, each motion chain has one revolute joint, one prismatic joint, and one spherical joint; in particular, the 3-RPS parallel mechanism has two rotational degrees of freedom and one translational degree of freedom; a second angle sensor module 1008 is mounted on the second support assembly 702, used to measure the rotation angles of the three revolute joints; a fourth laser rangefinder sensor 1009 is mounted on the third-stage platform panel 604, used to monitor the displacement of the fourth-stage moving platform 701. In particular, rigid parallel robots have many advantages such as high structural stiffness, high load-bearing capacity, high motion accuracy and simple inverse kinematics solution. Here, the 3-RPS parallel mechanism is selected as the pose adjustment device for the rigid-flexible coupling welding robot module 9, which has the advantages of high motion accuracy and simple control, and is convenient for subsequent large-scale design of the device.

[0066] like Figure 13As shown, the robot rotating platform module 8 in this embodiment includes a servo drive motor 801, a static platform (i.e., the four-stage moving platform 701 in the robot posture adjustment module 7), a motor output shaft flange 802, a thrust self-aligning roller bearing 803, a first thrust bearing support 804, a second thrust bearing support 805, and a five-stage rotating platform 806.

[0067] A servo drive motor 801 is vertically mounted on the upper side of the four-stage moving platform 701 by bolts. The output shaft of the servo drive motor 801 passes through a pre-drilled hole in the four-stage moving platform 701, and a motor output shaft flange 802 is installed at the shaft end. The motor output shaft flange 802 is connected to the five-stage rotating platform 806 by a bolt group. The edge of the first thrust bearing support 804 is machined with threaded holes. Between the four-stage moving platform 701 and the five-stage rotating platform 806, the first thrust bearing support 804 is mounted on the four-stage moving platform 701 by screws. The thrust self-aligning roller bearing 803 and the second thrust bearing support 805 are fitted onto the first thrust bearing support 804 from the inside out. In addition, the outer ring of the first thrust bearing support 804 is threaded to the inner ring, facilitating the installation of the thrust self-aligning roller bearing 803 and the second thrust bearing support 805. The second thrust bearing support 805 has through holes machined on its edge, which are bolted to the five-stage rotary platform 806. Specifically, the lower ring of the first thrust bearing support 804 and the upper ring of the second thrust bearing support 805 are respectively installed on the bottom and top surfaces of the thrust self-aligning roller bearing 803. A third angle sensor 1010 is installed on the upper side of the five-stage rotary platform 806 and connected to the motor output shaft flange 802 to monitor the rotation of the five-stage rotary platform 806.

[0068] like Figure 1 , Figure 12 , Figure 13 As shown, in this embodiment, the robot posture adjustment module 7 and the robot rotation platform module 8 are sequentially installed on the lower side of the robot lateral movement module 4, and the rigid-flexible coupling welding robot module 9 and the five-stage rotation platform 806 in the robot rotation platform module 8 are connected by bolt groups.

[0069] In this embodiment, a two-level robot pose adjustment control mechanism is defined, wherein the robot pose adjustment module 7 and the robot rotation platform module 8 serve as the second-level robot pose adjustment device to realize the fine adjustment of the welding robot's posture, namely roll motion, pitch motion, yaw motion and vertical lifting.

[0070] like Figure 14 As shown, the rigid-flexible coupling welding robot module 9 in this embodiment includes a robot static platform 901, a robot moving platform 902, a flexible cable drive system module 903, a flexible cable system 904, a radial extension module 905, a variable stiffness tensioning module 906, and a welding torch module 907.

[0071] The flexible cable drive system module 903 is mounted on the upper surface of the robot stationary platform 901, with the robot rotating platform module 8 above it. The robot moving platform 902 is located below the rigid-flexible coupling welding robot module 9, and the robot moving platform 902 always remains parallel to the robot stationary platform 901. The flexible cable system 904 connects the robot stationary platform 901 and the robot moving platform 902 to form a flexible motion chain. In particular, the radial extension module 905 and the variable stiffness tension module 906 are nested and further installed between the robot stationary platform 901 and the robot moving platform 902 to form a rigid motion chain, realizing the adjustment of the robot's radial position and controlling the overall stiffness of the robot. The welding torch module 907 is mounted on the lower side of the robot moving platform 902 to realize the welding operation.

[0072] like Figure 14 As shown, both the robot static platform 901 and the robot moving platform 902 are equilateral triangle structures. Three sets of through holes 901-1 are machined along the equilateral triangle on the robot static platform 901. The robot static platform 901 is connected to the five-stage rotating platform 806 in the robot rotating platform module 8 through three sets of fixing bolts 901-2. A flexible cable drive system 903 is arranged between the five-stage rotating platform 806 and the robot static platform 901. Three flexible cable lifting rings 902-1 are machined along the equilateral triangle on the robot moving platform 902. A first Hooke hinge assembly 902-2 is installed at the center of the upper surface of the robot moving platform 902.

[0073] like Figure 14 , Figure 15 As shown, the flexible cable drive system module 903 of this embodiment includes three sets of flexible cable drive systems arranged along an equilateral triangle. Each flexible cable drive system includes a support base 903-1 mounted on the robot's static platform 901 by bolts, and a flexible cable drive servo motor 903-2 and a flexible cable drum 903-4 mounted on the support base 903-1. Specifically, the flexible cable drive servo motor 903-2 and the flexible cable drum 903-4 are connected by a synchronous pulley assembly 903-3. Furthermore, the flexible cable drum 903-4 includes two sets of symmetrical spirals to wind two parallel flexible cables. Therefore, the rotation of the flexible cable drive servo motor 903-2 is transmitted through the synchronous pulley assembly 903-3 and converted into the rotation of the flexible cable drum 903-4, thereby driving the parallel flexible cable branches to achieve contraction and release.

[0074] like Figure 16 , Figure 17As shown, the flexible cable system 904 in this embodiment includes three sets of parallel flexible cable systems arranged along an equilateral triangle; each parallel flexible cable system includes a first guide wheel 904-1 and a first guide wheel support 904-2 installed on the upper side of the robot stationary platform 901, and a second guide wheel 904-3 and a second guide wheel support 904-4 installed on the lower side of the robot stationary platform 901; compared with the first guide wheel support 904-2 being installed on the inner short side of the through hole 901-1 by screws, the second guide wheel support 904-4 is installed on the outer side to avoid friction between the flexible cable and the robot stationary platform 901.

[0075] Since the spirals on both sides of the flexible cable drum 903-4 are arranged symmetrically, the first flexible cable 904-5 wound on one side of the flexible cable drum 903-4 and the second flexible cable 904-6 wound on the other side of the flexible cable drum 903-4 can be contracted and released simultaneously. The first flexible cable 904-5 and the second flexible cable 904-6 extend from the flexible cable drum 903-4, pass through the first guide wheel 904-1 and through the through hole 901-1, pass through the second guide wheel 904-3 and are finally fixed to the two flexible cable rings 902-1 on the robot moving platform 902 respectively. The other two sets of parallel flexible cables are handled in the same way. In particular, the first flexible cable 904-5 is connected to the cable displacement sensor module 1011 before passing through the second guide wheel 904-3 in order to control the rigid-flexible coupling welding robot and monitor its motion.

[0076] like Figure 14 As shown, since the welding torch module 907 is installed on the lower side of the robot moving platform 902, the rigid-flexible coupling welding robot module 9 needs to have sufficient rigidity in order to realize the welding function. In this embodiment, a variable stiffness tensioning module 906 is designed based on multiple sets of spring devices to ensure that the flexible cable system 904 is passively tensioned. In order to realize rapid welding of complex welds and welding of complex weldments, especially cavities and other geometrically limited parts, the welding torch module 907 needs to extend radially. In this embodiment, a radial extension module 905 is designed to realize the radial extension of the robot moving platform 902, realize a large adjustment of the radial position of the welding torch module 907, avoid frequent robot pose changes, and improve welding efficiency.

[0077] like Figure 14 , Figure 17As shown, the radial extension module 905 of this embodiment includes a second Hooke hinge assembly 905-1 mounted on the robot's static platform 901, a third stepper motor 905-2, a flange 905-3, and a lead screw 905-4 mounted on the lower side of the second Hooke hinge assembly 905-1. The flange 905-3 is connected to the lower support of the second Hooke hinge assembly 905-1 by multiple sets of bolts. A second coupling 905-5 is also installed between the flange 905-3 and the lower support of the second Hooke hinge assembly. One end of the second coupling 905-5 is connected to the output shaft of the third stepper motor 905-2, and the other end is connected to the lead screw 905-4.

[0078] like Figure 17 , Figure 18 As shown, it also includes two fifth guide rails 905-6 and a stop block 905-8. The two ends of the fifth guide rail 905-6 are respectively mounted on the flange 905-3 and the stop block 905-8 by screws. A nut slider 905-9 and a first sleeve 905-7 are mounted on the lead screw 905-4, and the first sleeve 905-7 is connected to the nut slider 905-9 by screws. The radial extension module 905 drives the lead screw 905-4, which is fitted with the nut slider 905-9 and the first sleeve 905-7, to rotate through the third stepper motor 905-2. The nut slider 905-9 further converts the rotational motion of the lead screw 905-4 into sliding motion, thereby realizing the extension of the rigid motion chain.

[0079] In particular, such as Figure 17 , Figure 18 and Figure 19 As shown, a set of through holes is machined on flange 905-3, and a set of threaded holes are machined on the outer rings 906-2 and 906-3 of the second sleeve 906-1. Multiple sets of screw spring mechanisms (eight sets are used as an example here) are installed on the through holes and threaded holes of flange 905-3, outer ring 906-2 of the first sleeve, and outer ring 906-3 of the second sleeve. The bottom of the screw spring assembly is fixedly installed on the threaded hole of the outer ring 906-3 of the second sleeve, and the top passes through the through hole on flange 905-3.

[0080] Specifically, such as Figure 19As shown, the screw spring mechanism has threads machined on a specific stroke of the threaded rod 906-4, with the remaining portion being a smooth rod. A spring 906-5 is fitted onto the threaded rod 906-4, and a double-ended nut 906-6 is installed on the threaded portion of the threaded rod 906-4. Specifically, both the inner and outer rings of the double-ended nut 906-6 are threaded, with the inner ring thread connecting to the threaded portion of the threaded rod 906-4, and the outer ring connecting to the threaded hole on the outer ring 906-3 of the second sleeve. Therefore, when the outer ring of the double-ended nut 906-6 is connected to the threaded hole on the outer ring 906-2 of the first sleeve, the screw spring mechanism provides elastic force to the robot system to keep the flexible cable system 904 tensioned. Otherwise, when the outer ring of the double-ended nut 906-6 is disconnected from the threaded hole on the outer ring 906-2 of the first sleeve, the screw spring mechanism no longer provides elastic force to the robot system.

[0081] Therefore, by selecting an appropriate number of screw spring mechanisms to provide elastic force to the variable stiffness tensioning module 906, the stiffness variation of the rigid branch of the rigid-flexible coupling welding robot module 9 can be realized.

[0082] In summary, this embodiment presents a rigid-flexible coupling welding robot system with omnidirectional autonomous movement capability, significantly expanding the operational coverage area. The rigid-flexible coupling robot can efficiently handle non-standard weldments and complex weld seams, supporting rapid switching between welding processes. A high-precision pose adjustment device is designed to further expand the workspace and improve overall welding efficiency.

[0083] This embodiment discloses a working method for the above-mentioned mobile rigid-flexible coupling welding robot system, such as... Figure 20 As shown, the process is as follows: Step 1: Initialize the system, turn on and test the sensors, calibrate the system and record the initial signals of each sensor; Step 2: Omnidirectional movement of the movable base: Based on the depth camera 1001 and the lidar 1002, the robot is located and the scene is mapped. The robot system's motion trajectory is planned, and the movable base 1 is driven to move omnidirectionally to reach the designated work position. Step 3, Multi-view 3D Reconstruction: The hydraulic lifting module 2 drives the system frame 3 to lift vertically, and the third ball screw module 303 drives the weldment scanning vision sensor 1003 to acquire local weldment point cloud data. High-quality weldment point cloud is obtained through multi-view 3D reconstruction methods (such as the Iterative Closest Point (ICP) algorithm). Step 4: For large and complex welded parts, executing Step 2 to Step 3 once can only obtain local welded part point cloud information. In order to obtain the complete welded part point cloud, it is necessary to repeat Step 2 to Step 3 and register multiple local welded part point clouds until the welded part point cloud reconstruction is completed. Step 5: Based on the geometric characteristics of the weldment, generate the weld seam in the welding manufacturing system deployed in the cloud; Step 6: Group and sort the multiple welds according to weld characteristics, workpiece geometry and task priority; in particular, strictly separate welds involving exterior facade welding from other welds, and strictly separate welds whose length exceeds the workspace of the robot system base when stationary from other welds. Step 7: Depending on whether the weld group is an exterior welding task, determine whether to use the exterior welding auxiliary module 6 to drive the three-level platform panel 604 and its lower robot posture adjustment module 7, robot rotation platform module 8 and rigid-flexible coupling welding robot module 9 to rotate 90° simultaneously. The specific implementation method has been described in detail above. Step 8: Generate the welding torch trajectory based on the weld seam characteristics and the kinematics of the welding robot system. Further, based on the scene map and the point cloud of the weldment, the hydraulic lifting module 2 drives the system frame 3 to lift and lower to adapt to the size of the part and avoid obstacles, preventing interference between the robot system and the working environment and the weldment. Step 9, Robot pose adjustment method: First, the robot's initial pose adjustment is performed using the robot's lateral movement module 4 and robot's longitudinal movement module 5, namely horizontal movement, vertical lifting and rolling motion. The purpose is to move the welding robot near the workpiece while avoiding collisions. Furthermore, the robot posture adjustment module 7 and the robot rotation platform module 8 are used to finely adjust the robot's posture, namely roll, pitch, yaw and vertical lifting. The purpose is to adjust the welding torch to the weld start point and adjust the welding torch angle to facilitate arc initiation. Step 10: Based on the welding torch trajectory, the robot longitudinal movement module 5, the robot lateral movement module 4, the robot posture adjustment module 7, the robot rotation platform module 8, and the rigid-flexible coupling welding robot module 9 work together to achieve continuous welding operations. During this process, each robot posture adjustment module cyclically performs adjustment operations to ensure stable and efficient welding. Step 11: For welds whose length exceeds the workspace of the robot system base when stationary, the process needs to be repeated in segments: i. Steps 2 to 3; ii. Steps 8 to 10: Long weld seams are welded using the motion assistance of a movable base; Step 12: Repeat steps 8-11 after each weld is completed until a set of welds is completed; Step 13: Repeat steps 7-11 after each set of welds is completed, until all welds are completed.

[0084] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A mobile rigid-flexible coupling welding robot system, characterized in that, include: The movable base module (1) includes a frame module (102) and a wheel module (103) that can move omnidirectionally within the welding work scene, and is used to achieve the operation scene coverage of the welding robot system; The hydraulic lifting module (2) includes a hydraulic cylinder (202) and kinematic components mounted on a movable base module (1) for lifting the welding robot system frame. The system framework (3) is installed above the hydraulic lifting module (2) to support the robot lateral movement module (4), the robot longitudinal movement module (5), the exterior welding auxiliary module (6), the robot posture adjustment module (7), the robot rotating platform module (8) and the rigid-flexible coupling welding robot module (9), thus constructing the overall system structure. The rigid-flexible coupling welding robot module (9) is a parallel flexible cable driven welding robot device used to adjust the position and posture of the welding gun module (907) to realize all-round welding of complex weldments. The robot longitudinal movement module (5) includes a ball screw module and kinematic pair components, which are used to adjust the longitudinal position and roll angle of the welding robot device. The robot lateral movement module (4) is a moving platform composed of two-stage guide components and a drive device, used to realize the lateral position adjustment of the welding robot device located below it; The exterior welding auxiliary module (6) is a deployable mechanism that rotates along the outside of the system frame (3). It uses at least two sets of electromagnetic clutch-based drive systems to achieve alternating transmission between the welding robot device along the robot's lateral movement module (4) and the lower side of the deployable mechanism, thereby assisting in the exterior welding operation. The robot posture adjustment module (7) is located below the robot lateral movement module (4). It is a 3-RPS parallel mechanism. By controlling the motion of the three motion chains, the two rotations and one translation of the welding robot device can be adjusted. The robot rotation platform module (8) is located between the robot posture adjustment module (7) and the rigid-flexible coupling welding robot module (9) and is used to adjust the rotation of the rigid-flexible coupling welding robot module (9). The sensor system module (10) is used for positioning the movable base module (1), and for monitoring the motion of the robot lateral movement module (4), robot longitudinal movement module (5), facade welding auxiliary module (6), robot posture adjustment module (7), robot rotating platform module (8) and rigid-flexible coupling welding robot module (9).

2. The mobile rigid-flexible coupling welding robot system according to claim 1, characterized in that, The system frame (3) is a truss structure, which includes four symmetrically installed structural support components (301) and transverse linkage components (302). The movable base module (1) and the hydraulic lifting module (2) are installed on the lower side of the structural support components (301) in sequence. The robot longitudinal movement module (5) is vertically installed in the middle of the structural support components (301), and the robot transverse movement module (4) is located in the middle of the system frame (3) and installed on the lower side of the robot longitudinal movement module (5). The exterior welding auxiliary module (6) is hinged to the side of the structural support components (301) and connected to the transverse linkage components (302) through a linkage.

3. The mobile rigid-flexible coupling welding robot system according to claim 1, characterized in that, The robot's lateral movement module (4) includes a primary platform panel (401) that connects to the ball screw module in the robot's longitudinal movement module (5). Below the primary platform panel (401) are a lateral movement module drive assembly (403) and a lateral movement module guide assembly (404). The lateral movement module drive assembly (403) is a long-stroke ball screw module, and the lateral movement module guide assembly (404) includes two levels of guide assemblies: The primary guide assembly includes two first guide rails (404-1) and a primary moving platform (404-2). The primary moving platform (404-2) is fixedly mounted on the lead screw nut (403-4) of the lateral moving module drive assembly (403). The secondary guide assembly includes two second guide rails (404-3) located outside the first guide rail (404-1) and a secondary platform panel (404-4). The secondary platform panel (404-4) is connected to the second guide rail (404-3) via the second guide rail slider (404-5) and is connected to the lower surface of the primary moving platform (404-2) to drive the secondary platform panel (404-4).

4. The mobile rigid-flexible coupling welding robot system according to claim 1, characterized in that, The exterior welding auxiliary module (6) includes a second ball screw (601) mounted on a transverse link assembly (302) of the system frame (3), and a connecting rod (603) hinged to the slider of the second ball screw module (601). The connecting rod (603) is hinged to a deployable platform (602). The deployable platform (602) is hinged to the front of the structural support assembly (301) via a pivot (608). Driven by the second ball screw module (601), the deployable platform (602) can rotate around the pivot (608).

5. A mobile rigid-flexible coupling welding robot system according to claim 4, characterized in that, Two sets of tertiary platform panel drive modules (605) and two sets of tertiary platform panel guide modules (606) are provided on the lower surface of the secondary platform panel (404-4) of the deployable platform (602) and the robot lateral movement module (4). The tertiary platform panel (604) is connected to the guide rail slider of the tertiary platform panel guide module (606) and moves linearly with a single degree of freedom along the lower surface of the deployable platform (602) and the secondary platform panel (404-4). The three-stage platform panel drive module (605) is connected to the drive gear (605-1) via the first stepper motor (605-3) to mesh with the driven rack (605-2) on the three-stage platform panel (604). The electromagnetic clutch assembly between the output shaft of the first stepper motor (605-3) and the drive gear (605-1) is engaged or disengaged to realize the alternating meshing of the driven rack (605-2) with the drive gears (605-1) of the two sets of drive devices for motion transmission.

6. A mobile rigid-flexible coupling welding robot system according to claim 4, characterized in that, The exterior welding auxiliary module (6) also includes at least four sets of three-level platform panel limiting devices (607). The three-level platform panel limiting devices (607) include a second-level platform panel (404-4) installed on the robot's lateral movement module (4) and a fifth guide groove (607-3) installed on the edge of the unfoldable platform (602). A second stepper motor (607-1) is fixedly connected to the fifth guide groove (607-3). The second stepper motor (607-1) drives the gear (607-2) to mesh with the rack (607-5) inside the sliding limiting component (607-4), thereby driving the sliding limiting component (607-4) with the baffle (607-6) to move up and down along the fifth guide groove (607-3) to limit the three-level platform panel (604).

7. A mobile rigid-flexible coupling welding robot system according to claim 1, characterized in that, The robot posture adjustment module (7) includes three motion branches and their motion pairs that connect to the three-level platform panel (604) of the exterior welding auxiliary module (6). A reversing electric cylinder (703) is installed on each of the three motion branches to form a drive moving pair. The three motion branches are connected to the four-level moving platform (701), which is connected to the robot rotation platform module (8). The robot posture adjustment module (7) has two rotational degrees of freedom and one translational degree of freedom.

8. A mobile rigid-flexible coupling welding robot system according to claim 1, characterized in that, The robot rotating platform module (8) includes a servo drive motor (801) connected to the four-stage moving platform (701) of the robot posture adjustment module (7). The output shaft of the servo drive motor (801) is connected to the motor output shaft flange (802). The motor output shaft flange (802) passes through the thrust self-aligning roller bearing (803) and is connected to the five-stage rotating platform (806). The robot rotating platform module (8) has one rotational degree of freedom.

9. A mobile rigid-flexible coupling welding robot system according to claim 1, characterized in that, The rigid-flexible coupling welding robot module (9) includes a robot stationary platform (901) located below the five-stage rotating platform (806) of the robot rotating platform module (8), and a robot moving platform (902) parallel to the robot stationary platform (901). A flexible cable system (904) is connected between the robot stationary platform (901) and the robot moving platform (902) to form a flexible motion branch. Nested radial extension modules (905) and variable stiffness tensioning modules (906) are provided between the robot stationary platform (901) and the robot moving platform (902) to form a rigid motion branch. A welding torch module (907) is connected to the lower side of the robot moving platform (902). Each flexible cable system (904) drives the flexible cable drum (903-4) to rotate via the flexible cable drive servo motor (903-2), thereby driving the parallel flexible cable branches that bypass the flexible cable drum (903-4) to achieve contraction and release; The radial extension module (905) drives the lead screw (905-4) with the nut slider (905-9) and the first sleeve (905-7) to rotate through the third stepper motor (905-2), thereby realizing the extension of the rigid motion chain; The variable stiffness tensioning module (906) achieves tensioning of the flexible cable connected to the robot moving platform (902) and robot stationary platform (901) at the bottom of the variable stiffness tensioning module (906) by extending and retracting the screw spring mechanism connected below the radial extension module (905), and adjusts the stiffness of the rigid motion branch by controlling the number of springs connected to the screw spring mechanism.

10. A welding method for a mobile rigid-flexible coupling welding robot according to any one of claims 1-9, characterized in that, include: S1, Welding robot system initialization, sensor system module (10) testing, system calibration; S2, the movable base module (1) performs robot positioning and scene mapping based on the sensor system module (10) and plans the motion trajectory of the welding robot system; S3, the hydraulic lifting module (2) drives the system frame (3) to lift vertically, and the sensor system module (10) on the system frame (3) obtains local weldment point cloud data, and obtains high-quality weldment point cloud through multi-view three-dimensional reconstruction method; S4. For large and complex welded parts, repeat steps S2-S3 to register multiple local welded part point clouds until the welded part point cloud reconstruction is completed. S5 generates welds in a cloud-based welding manufacturing system based on the geometric features of the weldment. S6, group and sort multiple welds according to weld characteristics, workpiece geometry and task priority; separate welds involving exterior facade welding from other welds, and separate welds whose length exceeds the working space of the movable base module (1) of the welding robot system in a static state from other welds. S7. Depending on whether the weld group is an exterior welding task, determine whether to use the exterior welding auxiliary module (6) to drive the three-level platform panel (604) and its lower robot posture adjustment module (7), robot rotation platform module (8) and rigid-flexible coupling welding robot module (9) to rotate 90°. S8, based on the weld seam characteristics and the motion of the welding robot system, the welding gun trajectory is generated. Combined with the scene map and the point cloud of the welded parts, the hydraulic lifting module (2) drives the system frame (3) to lift and achieve obstacle avoidance. S9, use the robot longitudinal movement module (5) and the robot lateral movement module (4) to perform preliminary pose adjustment of the robot's vertical lifting, horizontal movement and rolling motion; The robot pose adjustment module (7) and the robot rotation platform module (8) are used to finely adjust the robot's pose, including roll, pitch, yaw and vertical lifting. S10, according to the welding torch trajectory, the robot longitudinal movement module (5), the robot lateral movement module (4), the robot posture adjustment module (7), the robot rotating platform module (8) and the rigid-flexible coupling welding robot module (9) work together to perform continuous welding operations; the robot posture adjustment module (7) and the robot rotating platform module (8) perform posture adjustment cyclically; S11, for welds whose length exceeds the working space of the welding robot system base when stationary, the process needs to be repeated in segments: i. Steps S2-S3; ii. Steps S8-S10, long weld seam welding is achieved with motion assistance from the movable base module (1); S12, after each weld is completed, repeat steps S8-S11 until a set of welds is completed; S13. After each set of welds is completed, repeat steps S7-S11 until all welds are completed.

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