Research And Implementation Of Control Technology For Arc Welding Robot

Arc welding is a very important application for industrial robot. Compared withtraditional manual welding and machine welding, robot welding is superior for its highefficiency, good quality and high flexibility. With the developing of auto industry andconstruction machinery industry, arc welding robot will have broad application prospect.This thesis studies and optimizes algorithm of kinematics and trajectory planning forarc welding robot. It introduces the robot joint configurations, which specify robot intothree joint conditions:“front/back”“up/down”“flip/no-flip”, to solve the problems ofkinematics multiple solutions and singular point avoidance. It divides robot trajectoryplanning into translational and rotational trajectory planning, establishes path equationsand interpolates for these two processes, and designs robot’s Cartesian linear and circulartrajectory planning methods based on these concepts.This thesis presents a multi-point calibration algorithm for arc welding robot’s torchcalibration and workpiece calibration. The algorithm uses least squares to fit tool centerpoint (TCP) position and coordinate transformation to calculate tool coordinate frame(TCF) orientation and workpiece frame. The calibration algorithm is also applicable toother types of industrial robot.Compared with the general industrial robot, arc welding robot has its own controlcharacteristics. In allusion to the key technologies of arc welding robot, this thesisresearches the algorithm of robot weaving function based on path coordinate system tomeet the requirement of weaving welding; it researches the algorithm of robot andpositioner’s coordinated movement to guarantee the well welding point of welding torchand seam; it gives the method to connect robot controller and welding power supply, andinvestigates the signals control method of four welding processes, arc ignition, mainwelding, arc ending and burning back.On the basis of before, the arc welding robot system based on HNC-08is developed.The software realizes upper-lower computer communications with robot controller andteach pendant, and integrates the control instructions and data structures of arc weldingrobot.