Research On Software Control System Of All-position Autonomous Welding Robot With Obstacle-Passing Capability

In order to carry out autonomous welding on all-position work piecesand large non-structured equipment, it is urgent to develop a new type ofmobile welding robot, and software control system is the key factor of therobot system to realize moving in long distance, large scale and performingwelding tasks on complicated and large-scale structure such as fillet seam.This paper focus on developing a multi-threading software control systemon a self-developed mobile welding robot with obstacle-climbing andall-position-welding capabilities with the aim to equip the robot withteaching and playback function and independent operation function.Intelligent welding robot is combined with a variety of hardware.Based on communication interface and rules supported by hardware onmobile welding robot, this paper try to establish communication betweenhost computer and various hardware in order to realizing auto control.Because several subsystems have to operate at the same time, multi-taskingtechnics is applied. The control system is divided into four dependentthreads of two parts, walking and welding part. Walking part of the controlsystem is consist of network cameras thread for detecting macroenvironment and car body thread, two threads working together to fulfill thewalking, turning, wall-climbing and obstacles-passing job. Welding partinclude CCD camera thread for capturing work piece images andmanipulator thread, they responsible for before-welding weld beamrecognition, in-welding correction, as well as basic welding functions likearcing, welding, and arc quenching. During obstacle-passing and welding, there will be necessary communication between robot’s car body thread andmanipulator thread to synchronize their executing steps. Then this paperdiscussed constructing software structure based on object-oriented technics.Different hardware modules are encapsulated into independent classes, andprovide external interface. Object-oriented program grant software withcode reuse, self-sufficient reusability and enabling collaboration through theuse of linked modules.To test the overall performance of control software on actual mobilewelding robot, the system is run under basic index test and welding,obstacle-passing and wall-climbing test, continuous passing testing andcomprehensive experiment. Through experimental verification, the mobilewelding robot meets the project requirements; it can pass obstacles andmake turns on vertical wall. The robot can move forward while passingobstacles that is continuous passing, and the robot can finish welding jobsparallel. Both software modules and hardware units do not interfere witheach other. The experiments also approved that communication is correctbetween control PC and hardware units, and robot can finish complex taskby software control. Further research will focus on finding better parametercombinations to improve the robot’s walking and welding performance.