Self-walking type spot welding robot and control method thereof

Abstract

The invention relates to a self-walking type spot welding robot and a control method thereof, the structure comprises a welding robot main body, a walking device and a control system, the welding robot main body adopts a six-degree-of-freedom industrial robot, and an end effector is a welding gun; the walking device comprises a chassis and crawler wheels arranged on the two sides of the chassis, each crawler wheel comprises a crawler, a guide wheel, a driving wheel and a planet wheel, and the guide wheels, the driving wheels and the planet wheels are arranged in the crawler in a non-equilateral triangle mode. Magnetic sheets which are sequentially arranged in the walking direction are arranged in the crawler belt, and the crawler belt wheels are controlled to walk on the steel structure by sequentially electrifying the magnetic sheets; the control system comprises a demonstrator, and a welding seam tracking system, a welding controller and a motion controller which are in signal connection with the demonstrator; the welding seam tracking system adopts a visual sensor to track a welding seam; the welding controller controls the welding gun to perform spot welding; the motion controller controls on-off of the magnetic sheet. Free walking of the welding robot on the steel structure can be achieved, and remote control is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of engineering intelligent construction, and in particular to a self-propelled spot welding robot and a control method thereof. Background Art

[0002] Welding is a common manufacturing process that uses heat, high temperature or high pressure to join metals or other thermoplastic materials. The essence of welding is to use pressure or heating, without or with filler materials, to firmly connect separated metal materials by the diffusion and bonding of metal atoms. On the one hand, welding technology requires welders to have skilled operating skills, rich operating experience, and stable welding level; on the other hand, welding is a job with poor working conditions, high smoke and dust, high heat radiation, and high risk.

[0003] Spot welding is an efficient and economical connection method in the welding of building steel structures. The spot welding joint adopts the overlap form. Figure 1 As shown in the figure, the whole spot welding process includes four stages: pre-pressing, welding, crystallization, and resting. Specifically, pre-pressing: after overlapping the two welds 01, press the weld 01 between the two cylindrical electrodes 02; welding: a large current is passed between the electrodes 02. Since the contact resistance of the two welds 01 is large, the metal is melted by resistance heat, and the power is turned off when the liquid metal reaches a certain proportion; crystallization: under the action of pressure, it cools and solidifies to form a weld 03; rest: after the melting point is completed, the electrode moves to the next point. The principle of spot welding is to use the heat energy generated by resistance heat to melt the metal and form a liquid molten pool (molten core). Resistance heat resistance includes three parts: contact resistance between workpieces, contact resistance between electrode and workpiece, and resistance of the workpiece itself. Spot welding can be divided into single-sided spot welding (single-sided single point, single-sided double points, single-sided multiple points) and double-sided spot welding (double-sided single point, double-sided double points, double-sided multiple points) according to the position of the spot electrode relative to the weld. According to the number of welds formed at one time, it can be divided into single point, double point and multiple points.

[0004] The development of welding robots is closely related to the development of industrial robots. Among industrial robots (first generation robotic arm robots), about 40% are used in the field of welding. Welding robots are industrial robots engaged in welding work. They are equipped with welding tongs and welding guns at the end flange of ordinary industrial robots. The welding robot system generally includes the robot body (robotic arm), control cabinet, welding power supply, teaching pendant, wire feeding mechanism, gas supply system, welding gun, cable, and communication equipment (between the control system and the robot).

[0005] Correspondingly, welding robots have developed various welding methods such as resistance spot welding, arc welding, laser welding, electron beam welding, stir friction welding, etc.; their control forms have also evolved from single robot arm control to multi-axis synchronous control; and with the progress of electronic technology, computer technology, and software development, welding robots have made remarkable progress in many fields such as automation upgrade, spraying function expansion, machine dynamic visual assistance, contact and force sensor application, all-electric drive, microprocessor control, spatial motion freedom expansion, robustness and high precision under continuous operation, controller upgrade, human-machine friendly interface, programming efficiency, robot arm movement speed, image processing technology, cyclic moving track development, offline programming and simulation software development, laser beam guidance, multi-robot multi-axis synchronous control, wireless teaching, fast arc welding, vibration control learning, etc., and are also working towards portability and low energy consumption.

[0006] Spot welding robots have the characteristics of large load, fast movement, and strict requirements on working point posture, including small installation area, large working space, large carrying capacity, high stability, and long-term production.

[0007] In actual engineering steel structures, to obtain a qualified weld, it is necessary to match the trajectory, posture, speed and welding parameters of the welding robot. Although the welding robot is a highly automated intelligent equipment, under the existing technical capabilities, the operator still needs to complete teaching and programming through the cooperation of hands, brain, eyes, etc. Even with protective tools, welders still need to face possible work injuries such as harmful smoke, harmful gases, strong arc radiation, harmful light, high-frequency electromagnetic fields, radioactive substances, noise, and thermal radiation in long-term high-risk working environments. At the same time, skilled and skilled welders are becoming increasingly rare, and in scenarios involving high-altitude operations, operations in harsh environments, operations in closed spaces, long-term outdoor high or low temperature operations, etc., it is urgent to develop one or more welding robots to meet the actual welding needs of steel structure projects. In addition, most welding robots are welding robots with fixed robotic arms as the main body, and there is still a lot of room for improvement in actual engineering applications. Summary of the invention

[0008] The present invention provides a self-propelled spot welding robot and a control method thereof to solve the above technical problems.

[0009] In order to solve the above technical problems, the present invention provides a self-propelled spot welding robot, comprising a welding robot body, a walking device and a control system.

[0010] The welding robot body adopts a 6-DOF industrial robot, and the end effector is a welding gun;

[0011] The walking device is arranged at the bottom of the welding robot body, including a chassis and track wheels respectively arranged on both sides of the chassis, each track wheel includes a track and a guide wheel, a driving wheel and a planetary wheel arranged on the inner side of the track in a non-equilateral triangle, and the driving wheels on both sides are driven by motors respectively; magnetic sheets arranged in sequence along the walking direction are arranged in the track, and the walking of the track wheels on the steel structure is controlled by sequentially electrifying the magnetic sheets;

[0012] The control system includes a weld tracking system, a welding controller, a motion controller and a teaching pendant. The weld tracking system uses a visual sensor to track the weld; the welding controller controls the welding gun to perform spot welding; the motion controller controls the power on and off of the magnetic sheet; and the teaching pendant is respectively connected to the weld tracking system, the welding controller and the motion controller by signal.

[0013] Preferably, the guide wheel is located in front of the walking direction, and the driving wheel is located behind the walking direction. A main arm is connected between the guide wheel and the driving wheel. The middle part of the main arm is connected to the planetary wheel through a curved arm. The guide wheel, driving wheel and planetary wheel jointly support the crawler track.

[0014] Preferably, the outer surfaces of the guide wheel, the driving wheel and the planetary wheel are respectively provided with a plurality of first protrusions of the same size, and a first notch matching the first protrusion is left between two adjacent magnetic sheets, and the first notch cuts off the internal circuit.

[0015] Preferably, a plurality of wheels are mounted on the main boom, a plurality of second protrusions of the same size are provided on the outer surface of the wheels, a second recess matching the second protrusion is left between two adjacent first recesses on the track, and the diameter of the second recess is smaller than the diameter of the first recess.

[0016] Preferably, rotary encoders are installed at the joints of the welding robot body.

[0017] Preferably, the weld tracking system also includes a proximity sensor and / or a welding current and voltage sensor.

[0018] The present invention also provides a control method for the self-propelled spot welding robot as described above, comprising the following steps:

[0019] Step 1: placing the walking device on the steel structure, and the motion controller controls the walking device to walk on the steel structure, driving the welding robot body to move to the weld detected by the weld tracking system;

[0020] Step 2: Open the teaching pendant and pre-press the weldment using electrodes;

[0021] Step 3: Turn on the welding switch on the end effector, and the welding controller controls the welding gun to perform spot welding;

[0022] Step 4: Cut off the welding current and continue to apply pressure to the weldment with the electrode until the molten core cools and crystallizes;

[0023] Step 5: After one melting point is completed, the electrode is lifted to the initial lowered position, moved to the next point, and the next welding cycle begins until all melting points are welded;

[0024] Step 6: Turn off the welding switch through the remote control signal command of the teaching pendant;

[0025] Step 7: Welding is completed and weld inspection is performed.

[0026] Preferably, the operation steps of the teaching pendant include: creating a new operation program, teaching a motion trajectory, confirming a motion, and setting operation conditions.

[0027] Preferably, the welding robot body performs debugging preparation work before teaching, and the debugging preparation work at least includes locking the welding function, debugging the wire feeding device and debugging the shielding gas on and off.

[0028] Preferably, in step 7, weld inspection is performed two hours and one day after welding is completed.

[0029] Compared with the prior art, the self-propelled spot welding robot and the control method thereof provided by the present invention have the following advantages:

[0030] 1. The present invention uses the magnetic sheet on the crawler to install a walking device on the traditional welding robot. The magnetic sheet can be energized by the control circuit to control the magnetism. The crawler is powered on in sequence, and the crawler generates magnetic force due to the electromagnetic effect, so that the robot can walk freely and be controlled remotely on the high-altitude steel structure and the vertical steel structure.

[0031] 2. The present invention uses crawlers to cover guide wheels, drive wheels and planetary wheels to form deformable crawler wheels, and uses different crawler configurations to adapt to different mobile environments;

[0032] 3. The welding robot body in the present invention adopts the most common 6-DOF industrial robot with a mature control system and strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the spot welding process;

[0034] Figure 2 It is a schematic diagram of the overall structure of a self-propelled spot welding robot in a specific embodiment of the present invention;

[0035] Figure 3 A control system block diagram of a self-propelled spot welding robot in a specific embodiment of the present invention;

[0036] Figure 4 A schematic diagram of network connection of a self-propelled spot welding robot in a specific embodiment of the present invention;

[0037] Figure 5 The spot welding trajectory (traveling in a straight line) of a self-propelled spot welding robot in a specific embodiment of the present invention;

[0038] Figure 6 A welding principle diagram of a self-propelled spot welding robot in a specific embodiment of the present invention;

[0039] Figure 7 It is a structural schematic diagram of a track wheel in a specific embodiment of the present invention;

[0040] Figure 8 It is an expanded view of a crawler in a specific embodiment of the present invention;

[0041] Fig. 9 This is a schematic diagram of the power supply principle of a magnetic sheet in a specific embodiment of the present invention;

[0042] Fig.10 A position relationship diagram of a track wheel crossing an obstacle in a specific embodiment of the present invention;

[0043] Fig.11a and 11b They are respectively schematic diagrams of the front and back sides of a teaching pendant in a specific embodiment of the present invention;

[0044] Fig.12 A schematic diagram of the operation steps of a teaching pendant in a specific embodiment of the present invention;

[0045] Fig.13 It is a block diagram of a motion control system in a specific implementation manner of the present invention.

[0046] In the figure: 01-weldment, 02-electrode, 03-welding point;

[0047] 100-welding robot body, 110-welding gun, 120-welding clamp, 200-walking device, 210-chassis, 220-track, 221-magnetic sheet, 222-first notch, 223-second notch, 224-internal circuit, 230-guide wheel, 231-first protrusion, 240-driving wheel, 241-motor, 250-planetary gear, 260-main arm, 270-crank arm, 280-row wheel, 281-second protrusion, 300-control system, 310-weld seam tracking system, 320-welding controller, 330-motion controller, 340-teach pendant, 341-button, 342-function key, 343-mode selection switch, 344-switch key, 345-safety switch, 346-cable connector. DETAILED DESCRIPTION

[0048] In order to describe the technical solution of the above invention in more detail, specific embodiments are listed below to demonstrate the technical effects; it should be emphasized that these embodiments are used to illustrate the present invention but not to limit the scope of the present invention.

[0049] The self-propelled spot welding robot provided by the present invention is as follows: Figure 2 and Figure 3 As shown, it includes a welding robot body 100, a walking device 200 and a control system 300, wherein:

[0050] The welding robot body 100 adopts a 6-DOF industrial robot, and the end effectors are a welding gun 110 and a welding clamp 120, which are used to perform welding tasks. The welding robot body 100 in the present invention adopts the most common 6-DOF industrial robot, and the control system is mature and has strong versatility. Of course, the end effector can also be modified into a detachable interface form to increase the applicable scenarios.

[0051] The walking device 200 is arranged at the bottom of the welding robot body 100, including a chassis 210 and track wheels respectively arranged on both sides of the chassis 210, each track wheel includes a track 220 and a guide wheel 230, a driving wheel 240 and a planetary wheel 250 arranged in a non-equilateral triangle inside the track 220, and the driving wheels 240 on both sides are driven by motors 241 respectively; the track 220 is provided with magnetic sheets 221 arranged in sequence along the walking direction, and the walking of the track wheel on the steel structure is controlled by sequentially energizing the magnetic sheets 221. The present invention uses the magnetic sheets 221 on the track 220 to install a walking device on the traditional welding robot, and can energize the magnetic sheets 221 through a control circuit to control the magnetism, and realize the walking of the track 220 by sequentially energizing the magnetic sheets 221 on the track 220, and the track 220 generates magnetic force due to the electromagnetic effect, so that free walking and long-distance control can be achieved on high-altitude steel structures and vertical steel structures.

[0052] The control system 300 includes a weld tracking system 310, a welding controller 320, a motion controller 330 and a teach pendant 340. The weld tracking system 310 uses a visual sensor to track the weld; the welding controller 320 controls the welding gun 110 and the welding clamp 120 to perform spot welding; the motion controller 330 controls the power on and off of the magnetic sheet 221; the teach pendant 340 is respectively connected to the weld tracking system 310, the welding controller 320 and the motion controller 330 by signal, and the teach pendant 340 is used to perform manual operation, program writing, parameter configuration and monitoring on the welding robot body 100.

[0053] In some embodiments, the visual sensor may adopt a weld image information sensing system composed of a chemical process, which may obtain weld image information for identification and processing, and obtain information on whether the arc and the weld are deviated, the direction of deviation, and the amount of deviation, and adjust the alignment position of the welding gun 110 and the center of the weld based on this information, so as to achieve the purpose of accurately tracking the weld with the arc.

[0054] In some embodiments, please refer to Figure 4 The welding robot body 100, walking device 200, weld tracking system 310, welding controller 320, and motion controller 330 can be arranged at the remote site layer, and connected to the teaching pendant 340 of the local area network layer through the media layer (local area network) to realize remote operation of the welding robot body 100.

[0055] In some embodiments, please refer to Figure 5 The motion controller 330 controls the walking device 200 to move to the specified position, the weld tracking system 310 detects the weld position and status in real time and feeds back to the control system 300, and the welding controller 320 controls the welding robot body 100 to weld the welding point 03 in sequence, from the welding starting point to the welding ending point. The position of the welding robot body 100 does not move during the welding process.

[0056] In some embodiments, please refer to Figure 6 , the present application integrates various dispersed components in the traditional spot welding robot system. The integrated parts include the basic components of the traditional spot welding robot system: robot system, spot welding controller, welding tongs (including arc welding transformer), cable package (Dresspack), water and gas unit, welding tooling, electrode grinder, water cooling system, control system, safety system, etc. During the welding process, the welding tongs 120 clamp the weldment 01, the water and gas unit supplies water and gas to the welding robot body 100, and the welding controller 320 controls the welding gun 110 and the welding tongs 120 to achieve spot welding.

[0057] The present invention adopts a spot welding robot body 100. Since the resistance spot welding is an internal heat source, the heat is concentrated, the heating time is short, and the spot is always surrounded by a plastic ring during the formation process of the weld. Therefore, the resistance metallurgical process is simple, the heat-affected zone is small, the deformation is small, and the welding quality is good; the welding speed is fast and the production efficiency is high; except for consuming electric energy, no welding rods, welding wires, acetylene, flux, etc. are required, which saves materials and has a low cost. Compared with other welding, spot welding is a widely applicable, economical and fast welding method. It is particularly suitable for the rapid welding of some small components or thin components (thickness 0.005-8mm). It is particularly suitable for welding low-carbon steel, low-alloy steel, stainless steel, aluminum alloy and titanium alloy, copper and copper alloy and different materials.

[0058] Compared with welding, spot welding robots are simple to operate, have CNC operation, and autonomous fine-tuning, making it easy to achieve a high degree of automation, digitization, robotization, and intelligence.

[0059] In some embodiments, please refer to Figure 7 , the guide wheel 230 is located in front of the walking direction, the driving wheel 240 is located in the rear of the walking direction, a main arm 260 is connected between the guide wheel 230 and the driving wheel 240, the middle part of the main arm 260 is connected to the planetary wheel 250 through a crank 270, and the guide wheel 230, the driving wheel 240 and the planetary wheel 250 jointly support the crawler 220. When the two motors 241 driving the two driving wheels 240 have the same speed, the left and right crawlers 220 have the same speed, and the welding robot body 100 moves forward in a straight line at a uniform speed; when the speeds of the two motors 241 are inconsistent, the welding robot body 100 turns to the side with a slower speed.

[0060] In some embodiments, please refer to Figures 7 to 9 The outer surfaces of the guide wheel 230, the driving wheel 240 and the planetary wheel 250 are respectively provided with a plurality of first protrusions 231 of the same size, and a first notch 222 matching the first protrusion 231 is left between two adjacent magnetic sheets 221, and the first notch 222 cuts off the internal circuit 224. In this way, when the first notch 222 is engaged with the first protrusion 231, the internal circuit 224 is closed and energized to generate magnetism, and then adsorbed on the steel structure of the walking device 200.

[0061] In some embodiments, please refer to Figure 7 and Figure 8A plurality of wheels 280 are mounted on the main arm 260, and a plurality of second protrusions 281 of the same size are provided on the outer surface of the wheels 280. A second recess 223 matching the second protrusion 281 is left between two adjacent first recesses 222 on the track 220. The diameter r of the second recess 223 is smaller than the diameter R of the first recess 222. The second recess 223 will not cut off the internal circuit 224. The cooperation between the second recess 223 and the second protrusion 281 will not affect the power on and off of the magnetic sheet 221, and can increase the friction with the track 220.

[0062] Please focus on Fig.10 When the main arm 260 rotates around the axis on the crawler frame, the planetary wheel 250 is driven to rotate through the crank arm 270, thereby realizing different configurations of the crawler 220 to adapt to different moving environments, such as crossing steps, obstacles, uneven surfaces, etc.

[0063] The present invention uses a crawler composed of attached magnetic sheets 221 to replace wheels to directly contact the steel structure plane, which can not only buffer the road surface state, but also fit various types of steel structure planes to achieve barrier-free walking. Moreover, the magnetism of the crawler 220 is controlled by whether the magnetic sheet 221 is powered on or not, and the adsorption force on the steel structure plane is adjustable, making the application scenario more flexible.

[0064] In some embodiments, rotary encoders (not shown) are installed at the joints of the welding robot body 100 to achieve rapid speed regulation.

[0065] In some embodiments, the weld tracking system 310 also includes proximity sensors and / or welding current and voltage sensors, which can realize real-time control of the penetration state of the robot welding system. Specifically, in the process of intelligent upgrading, autonomous fine-tuning can be achieved by selectively installing welding current and voltage sensors (and cooperating with the PC control host and the corresponding AI program). When positioning the components to be welded, proximity sensors such as eddy current proximity sensors, photoelectric proximity sensors, ultrasonic proximity sensors, etc. can be installed. This embodiment integrates multiple sensors to realize environmental perception, information extraction and processing, and forms a certain closed-loop control through feedback from visual, tactile and other perceptions. It has a certain adaptability to changes in the external environment, such as automatic positioning of the welding starting position and automatic tracking of the weld.

[0066] The present invention also provides a control method for the self-propelled spot welding robot as described above, comprising the following steps:

[0067] Step 1: placing the walking device 200 on the steel structure, and the motion controller 330 controls the walking device 200 to walk on the steel structure, driving the welding robot body 100 to move to the weld detected by the weld tracking system 310;

[0068] Step 2: Open the teaching pendant 340 and use the electrode 02 to pre-press the weldment 01 (corresponding to the pre-pressing stage);

[0069] Step 3: Turn on the welding switch on the end effector, and the welding controller 320 controls the welding gun 110 and the welding clamp 120 to perform spot welding (corresponding to the welding stage);

[0070] Step 4: Cut off the welding current, and continue to apply pressure to the weldment 01 using the electrode 02 until the molten core cools and crystallizes (corresponding to the forging stage);

[0071] Step 5: After one melting point is completed, the electrode is lifted to the initial descending position, moved to the next point (corresponding to the rest stage), and the next welding cycle begins until all melting points are welded;

[0072] Step 6: Turn off the welding switch by remote control signal command through the teaching pendant 340;

[0073] Step 7: After welding is completed, weld inspection is performed. In this embodiment, weld inspection can be performed two hours and one day after welding is completed. The present invention can perform weld quality inspection and polishing and grinding of the weld area after welding is completed.

[0074] The present invention clearly provides a welding trajectory teaching programming process framework for a welding robot. Teaching programming is similar to the basic process of general robot teaching programming. There are two ways of teaching programming: one is programming first and then calibration; the other is programming and calibration at the same time. In the former, the programming operation site is separated, and the program can be written or imported into the teaching pendant in a relatively quiet environment. In the latter, programming and calibration are carried out at the same time, which is mainly used for scenes where the robot trajectory is uncertain and the robot action must be determined based on the site. Of course, more complex robot welding action control cannot be completed using a simple single-chip microcomputer or industrial computer, and corresponding exclusive control software should be developed based on the existing PC operating system. After determining the type of welding robot (such as arc welding, spot welding, laser welding, stirring welding, etc.), the welding process can also be determined, so the method of programming first and then calibration can be selected.

[0075] The present invention can realize remote control of multiple welding robots through the teaching pendant 340. Please refer to Fig.11a and 11b The teaching pendant 340 includes at least a button 341, a function key 342, a mode selection switch 343, a toggle key 344, a safety switch 345 and a cable connector 346, which can realize the manual operation, program writing, parameter configuration and monitoring functions of the robot.

[0076] In some embodiments, please refer to Fig.12The operation steps of the teaching pendant 340 include: creating a new operation program, teaching a motion trajectory, confirming (tracking) motion, and setting operating conditions. In addition, during the motion confirmation (tracking) process, the teaching points can be modified, added, or deleted according to actual conditions; and the operating conditions can be set in the manual operation mode or the automatic operation mode.

[0077] In some embodiments, please refer to Fig.12 The welding robot body 100 needs to be debugged and prepared before teaching. The debugging preparation work at least includes locking the welding function, debugging the wire feeding equipment and debugging the shielding gas on and off. These operations can be achieved in the "Production Screen" option.

[0078] In some embodiments, the control system 300 of the present invention can be developed using the Workspace system, which can realize PC-based offline programming of robots; or corresponding IPC (industrial computer), DCS (distributed control system), or other embedded control devices. The motion control system of the arc welding robot can be used as follows Fig.13 The system block diagram shown in the figure is remotely controlled. The remote control operation of welding robots in extreme environments such as nuclear, space, and deep sea requires not only the special characteristics of extreme environments such as radiation, air pressure, gravity, and temperature, but also the robot needs to have countermeasures in terms of mechanical structure, electrical design, sensing method, control technology, and process. Welding robots can also be used to complete the manufacturing of engineering machinery and energy equipment.

[0079] In summary, the self-propelled spot welding robot and the control method thereof provided by the present invention include a welding robot body 100, a walking device 200 and a control system 300. The welding robot body 100 adopts a 6-DOF industrial robot, and the end effector is a welding gun 110 and a welding clamp 120, which are used to perform welding tasks; the walking device 200 is arranged at the bottom of the welding robot body 100, including a chassis 210 and track wheels respectively arranged on both sides of the chassis 210, each track wheel includes a track 220 and a guide wheel 230, a driving wheel 240 and a planetary wheel 250 arranged on the inner side of the track 220 in a non-equilateral triangle arrangement, and the driving wheels 240 on both sides are respectively arranged on the inner side of the track 220. The crawler 220 is driven by a motor 241; the crawler 220 is provided with magnetic sheets 221 arranged in sequence along the walking direction, and the walking of the crawler wheels on the steel structure is controlled by sequentially energizing the magnetic sheets 221; the control system 300 includes a weld tracking system 310, a welding controller 320, a motion controller 330 and a teach pendant 340, and the weld tracking system 310 uses a visual sensor to track the weld; the welding controller 320 controls the welding gun 110 and the welding clamp 120 to perform spot welding; the motion controller 330 controls the power on and off of the magnetic sheets 221; the teach pendant 340 is respectively connected to the weld tracking system 310, the welding controller 320 and the motion controller 330 by signal. The present invention utilizes the magnetic sheet 221 on the track 220 to install a walking device on the traditional welding robot. The magnetic sheet 221 can be energized through a control circuit to control the magnetism. The magnetic sheet 221 on the track 220 is energized in sequence to realize the walking of the track 220, and the track 220 generates magnetic force due to the electromagnetic effect, so that free walking and long-distance control can be realized on high-altitude steel structures and vertical steel structures.

[0080] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A self-propelled spot welding robot, characterized in that: Including welding robot body, walking device and control system, The welding robot body adopts a 6-DOF industrial robot, and the end effector is a welding gun; The walking device is arranged at the bottom of the welding robot body, including a chassis and track wheels respectively arranged on both sides of the chassis, each track wheel includes a track and a guide wheel, a driving wheel and a planetary wheel arranged on the inner side of the track in a non-equilateral triangle, and the driving wheels on both sides are driven by motors respectively; magnetic sheets arranged in sequence along the walking direction are arranged in the track, and the walking of the track wheels on the steel structure is controlled by sequentially electrifying the magnetic sheets; The control system includes a weld tracking system, a welding controller, a motion controller and a teaching pendant, and the weld tracking system uses a visual sensor to track the weld; The welding controller controls the welding gun to perform spot welding; the motion controller controls the power on and off of the magnetic sheet; and the teaching pendant is respectively connected to the weld tracking system, the welding controller and the motion controller by signal.

2. The self-propelled spot welding robot according to claim 1, characterized in that: The guide wheel is located in front of the walking direction, and the driving wheel is located behind the walking direction. A main arm is connected between the guide wheel and the driving wheel. The middle part of the main arm is connected to the planetary wheel through a curved arm. The guide wheel, the driving wheel and the planetary wheel jointly support the crawler track.

3. The self-propelled spot welding robot according to claim 2, characterized in that: The outer surfaces of the guide wheel, the driving wheel and the planetary wheel are respectively provided with a plurality of first protrusions of the same size, and a first notch matching the first protrusion is left between two adjacent magnetic sheets, and the first notch cuts off the internal circuit.

4. The self-propelled spot welding robot according to claim 3, characterized in that: A plurality of wheels are installed on the main boom, and a plurality of second protrusions of the same size are provided on the outer surface of the wheels. A second recess matching the second protrusion is left between two adjacent first recesses on the track, and the diameter of the second recess is smaller than the diameter of the first recess.

5. The self-propelled spot welding robot according to claim 1, characterized in that: Rotary encoders are installed at the joints of the welding robot body.

6. The self-propelled spot welding robot according to claim 1, characterized in that: The weld seam tracking system also includes a proximity sensor and / or a welding current and voltage sensor.

7. A control method for a self-propelled spot welding robot as claimed in claim 1, characterized in that: The steps include: Step 1: placing the walking device on the steel structure, and the motion controller controls the walking device to walk on the steel structure, driving the welding robot body to move to the weld detected by the weld tracking system; Step 2: Open the teaching pendant and pre-press the weldment using electrodes; Step 3: Turn on the welding switch on the end effector, and the welding controller controls the welding gun to perform spot welding; Step 4: Cut off the welding current and continue to apply pressure to the weldment with the electrode until the molten core cools and crystallizes; Step 5: After one melting point is completed, the electrode is lifted to the initial lowered position, moved to the next point, and the next welding cycle begins until all melting points are welded; Step 6: Turn off the welding switch through the remote control signal command of the teaching pendant; Step 7: Welding is completed and weld inspection is performed.

8. The control method according to claim 7, characterized in that: The operation steps of the teaching pendant include: creating a new operation program, teaching a motion trajectory, confirming motion, and setting operation conditions.

9. The control method according to claim 8, characterized in that: The welding robot body performs debugging preparation work before teaching, and the debugging preparation work at least includes locking the welding function, debugging the wire feeding device and debugging the shielding gas on and off.

10. The control method according to claim 7, characterized in that: In step 7, the weld seam is inspected two hours and one day after welding is completed.

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