SERVO ABNORMALITY DETECTION

摘要

PURPOSE:To allow a motor to detect servo abnormality for sure, by comparing the sign of positional deviation with the rotating direction of motor in every sampling time and by judging it as servo-abnormal when both of them above are different in more than designated number of sampling attempts. CONSTITUTION:A position command section 100 compares a position command with a position feedback signal and outputs a speed command. A speed control 102 compares a speed command with a speed feedback signal and outputs a current command. A current control circuit 103 compares a current command with a current feedback signal and controls the current of a motor 105. On the other hand, the sign of positional deviation is compared with the rotating direction of the motor in every sampling step. If both of them are continuously different in more than designated number of sampling attempts, it is judged as servo-abnormal. In this way, the servo abnormality can be surely detected.