Utilization of conventional arc-welding robot by actual robot teaching (by a human operator) is not suitable for constructing a flexible production system, because applicability of the teaching data is limited to only the target robot.As a solution to this problem, the authors have proposed a compact computer aided welding system which consists of a personal computer and a conventional teaching-playback arc welding robot, and indicated the concept of off-line programming by a simple robot language. In the system, wled information processing is divided into four levels; task level, tool level, robot level and machine code level. At each level, necessary information is obtained from external files. In task level, source program of the weld is parsed and weld parts are extracted from the work model. In tool level, the motion of weld torch is generated on the work model at each weld line and between weld lines referring to both of work and torch models. In robot level, each angle of robot arms, which realizes required torch angle, is claculated considering the movable range of the robot. In machine code level, angle data of robot arms and weld conditions are combined together and converted into robot codes, which are transmitted to the robot controller through a communication line.Realization of torch motion in robot level is discussed for 5-axis articulated type robot. Possibility of required torch angle by the robot is checked by calculation of intersection between arm plane, in which robot's arms move, and movable range of torch rotation. Collision check and avoidance algorithm is shown, and its property was confirmed by an example program of the weld.
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Jan 1, 1992
Teruyoshi Sekino 
Open Access
