Servo control apparatus

A servo control apparatus comprising a plurality of electrically connected servo control circuits that are electrically connected to a reference control adjuster, each servo control circuit operationally connected to mechanically and independently apply torque to a shaft, wherein each servo control circuit comprises:

• a servo controller that performs a control computation for generating a torque command signal in response to a reference control signal received from the reference control adjuster, wherein the reference control signal directs the amount of torque applied to the shaft to drive a load;
• a servo amplifier electrically connected to the servo controller wherein the servo amplifier controls electric power in response to the command signal sent from the servo controller;
• a servo motor electrically connected to and powered by the servo amplifier, wherein the servo motor is supplied by electric power controlled by the servo amplifier, and wherein the servo motor applies torque to the shaft to drive the load;
• and
• a feedback detector mechanically connected to the servo motor and electrically connected to the servo controller, wherein the feedback detector detects the operating status of the servo motor and feeds the status back to the servo controller so that the servo motor is operated to drive the load, wherein each servo motor of the plurality of servo control circuits are mechanically interlocked with each other servo motor so that the load is driven by the combined torque generated by the plurality of servo control circuit& transmitted through a drive transmission mechanism,
• and when any of the plurality of servo control circuits operates abnormally each abnormally operating servo control circuit allows the respective servo motor to run freely thereby generating torque and each remaining normally operating servo control circuit operates to continuously drive the load to follow a reference control value determined by the reference control adjuster.