Robust control of large-scale prototypes for miniaturized optical image stabilizers with product variations

This paper presents robust control of large-scale prototypes for miniaturized optical image stabilizers (OIS's) with product variations. Based on the conceptual design of a miniaturized lens-tilting OIS for mobile applications, large-scale 3-DOF prototypes are fabricated as a proof of concept. Variations in geometrical parameter of the lens platform are produced to mimic unavoidable product variations in fabrication of the micro-scale devices. Using frequency response data, a model set with real parametric uncertainty is developed to represent the dynamics of the prototypes under product variations and force unbalance. A robust controller for the model set is designed based on μ-synthesis, and the closed-loop performance of hand shake compensation is verified experimentally on the prototypes. Experimental results show that the designed robust controller outperforms the classical controller consisting of lead-lag compensators and notch filters in compensating lens vibrations caused by involuntary hand shake while taking photos.