Position tracking control of an optical pick-up device using piezoceramic actuator

This paper proposes a piezoactuator-driven optical pick-up for compact disc -read only memory (CD-ROM) drive in order to achieve fine motion control of objective lens. The dynamic model of the proposed optical pick-up consisti ng of piezoceramic bimorph, wire suspension and objective lens is derived f rom Hamilton's principle. A state-space control model is subsequently formu lated by considering hysteresis behavior of the piezoactuator and frequency variation of the device as uncertainties. A sliding-mode controller, which is known to be robust to system uncertainties is designed for fine motion tracking control of the objective lens in vertical direction (focusing). Th e controller is then experimentally realized and position-tracking response s of the optical pick-up are presented in time domain. In addition, control durability is demonstrated by showing favorable tracking performance of a sinusoidal trajectory up to 8000 cycles of operation. (C) 2001 Published by Elsevier Science Ltd.