摘要

The present study considers an autofocusing laser probe system used for the measurement of the surface profile and roughness of an object. The system is based upon a modified pickup head of a commercially available DVD player which uses a voice coil motor (VCM) to drive an objective lens during the autofocusing process. It is known that hysteresis of the VCM during the autofocusing process reduces the precision of the measurement results. Consequently, the present investigation adopts a hysteresis model to develop a compensation method which can improve the accuracy of the optical pickup head within the measurement system.