A system consists of an input device (a), a CPU (b), a sensor (c) which detects whether a robot hand is holding a work or not, a servo control circuit (d), a servo motor (e) which drives the robot arm, a pulse coder (f) which detects the rotation angle of the servo motor (e) and a tacogenerator (g) which detects the number of revolution of the servomotor. The drive torque for the servo motor is calculated using a motion equation, of which the inertia term depends on the position of the robot arm. Since the variation of the robot arm position is relatively slow, the operation period on the inertia term is set longer than that of the torque to reduce computation.
ROBOT CONTROL APPARATUS