Industrial robot and its control unit

Abstract

A control unit for an industrial robot comprising a speed command device for outputting a speed command signal for the industrial robot and a servo control device which outputs to a servo motor of each of a plurality of axes of rotation of the industrial robot, in response to the speed command signal, an electric current corresponding to the speed command signal. The servo control performs feedback control of the industrial robot, in response to a signal from an encoder of each of the axes of rotation of the industrial robot, so as to actuate the servo motor at a speed designated by the speed command signal. The speed command device includes a comparison member for comparing an actual speed of the industrial robot calculated from a pulse train of a signal returning from the encoder with the speed designated by the speed command signal. When a difference between the actual speed of the industrial robot and the speed designated by the speed command signal exceeds a predetermined permissible value, the comparison member performs an abnormality eliminating process of the industrial robot.

Dependencies are inferred from the claim text.