Failure diagnostic device and failure diagnostic method

Abstract

A failure diagnostic device for performing a failure diagnosis on a multi-axis robot includes a position detector that detects a movement position of each of joint shafts included in the multi-axis robot, a torque detector that detects a disturbance torque applied to the joint shaft, a routine-operation determination circuit that determines whether or not the multi-axis robot is executing a predefined routine operation, from the movement position detected by the position detector, a reference-value calculation circuit that calculates a disturbance-torque reference value from the disturbance torque detected during execution of the routine operation, a torque correction circuit that corrects the disturbance torque detected while the multi-axis robot executes an operation different from the routine operation by using the disturbance-torque reference value, calculated by the reference-value calculation circuit, to thereby acquire a corrected disturbance torque, and a failure diagnostic circuit that performs a failure diagnosis.