PURPOSE: To attain reduction of a CPU load and offset control by performing precopying control based on a detection data of a sensor provided so as to precede relating to a moving direction of a control object, and providing a buffer for storing a correction amount of a precopying amount (offset amount).
CONSTITUTION: A torch 12 and a sensor 13 for detecting a welding position are mounted on the point end of a robot 11. The sensor 13 is set up in an advancing direction of a welding line, to perform teaching with the torch 12 serving as the reference in a condition that offset is provided between the sensor 13 and the torch 12. At the time of automatic operation by a robot control unit 15, a workpiece 14 is welded while performing correction. Memory size (m) of a buffer 51 for storing this correction of an offset amount is automatically produced in accordance with an offset length and a moving speed. A workpiece position is detected from the sensor 13, to add this detection amount stored in a buffer position corresponding to a number of (m) data stored in the storage buffer 51. Thus, optimum sensing control can be performed.
SHIINA TSUKASA
SHIBUYA HAJIME
HITACHI KEIYO ENG