Modeling and robust control of miniaturized magnetically-actuated optical image stabilizers

This paper proposes an uncertainty modeling and robust controller design method for miniaturized 3 degrees-of-freedom OISs to deal with its product variabilities. A mathematical model of OISs with product variabilities is developed based on finite element analysis of uncertainties specific for this device. μ-synthesis technique is applied to the uncertainty model to design a robust controller, in order to guarantee robust stability of the closed-loop system and optimize tracking performance against product variabilities. The performance of the μ-synthesis controller is compared with conventional nominal controllers using simulations. The μ-synthesis controller successfully stabilizes the closed-loop system for the entire uncertainty region and suppresses hand-shake disturbances more than 30% better then baseline controllers. This improvement can lead to significant enhancement of image blur in mobile phone cameras equipped with this OIS.