Robust H∞ control of miniaturized optical image stabilizers against product variabilities

This paper presents uncertainty modeling and robust controller design for 3 degrees-of-freedom miniaturized optical image stabilizers (OISs) against product variabilities. To develop a mathematical model of OISs with product variations, both model and uncertainty structures are determined by finite element analysis. The model parameters are identified based on experimental frequency responses. A robust H∞ controller design method is applied to the model, in order to guarantee robust stability of the closed-loop system and optimize OIS performance against the hand-induced vibrations of the OIS body. The proposed modeling and controller design method is experimentally validated with large-scale OIS prototypes. The experimental results demonstrate that the robust H∞ controller outperforms conventional and μ-synthesis controllers.