Improvement of Servo Transient Response by Frictional “Negative-Inertia” Mechanism

The negative-inertia mechanism consists of a double-worm drive with a small flywheel attached to the output shaft. By connecting the drive in parallel with the servo load, very high deceleration rates can be obtained. The drive thus effectively cancels most of the load inertia, as long as the load is decelerated. During acceleration, the drive adds slightly to the original load inertia. Characteristic design equations of the system are described, and experimental results presented. The drive is intended mainly for velocity servos, where very high decelerating torques are required without using clutch-brake mechanisms or excessively large servomotors.