Apparatus for controlling servo system employing piezo-electric actuator

Abstract

A first servo system (31) which feeds back at least position and speed and a second servo system (32) which effects integral control by feeding back position are connected in series. A first signal obtained by multiplying the output of the integral controller of the second servo system by a first gain is added to the position feedback signal of the first servo system, while a second signal obtained by multiplying the input of the integral controller of the second servo system by a second gain is added to the speed feedback signal of the first servo system. In this way, feedback control is effected using one mutual position detector, thereby eliminating the dynamic interference between the first and second servo systems, and thus enabling the two servo systems to be activated simultaneously. Also, the position of a moving member having mass is controlled by controlling the voltage applied to a piezoelectric actuator using a device for detecting the position and acceleration of the moving member and a device for effecting control. The applied voltage E of the piezo-electric actuator is determined on the basis of a signal obtained by inputting a signal representative of the acceleration to a first-order lag circuit. a position command, and gain constants.

Dependencies are inferred from the claim text.