Sliding Mode Control Using Virtual Eigenvalue Method for Compact Optical Image Stabilization Actuators

The latest research in optical image stabilization actuators (OISA) focuses on improving the image quality of high resolution cameras in a photographing optical system (POS). The focal image blur is always caused of external and environmental jitter when pictures of an image sensor are acquired by photographers. Several works concerned for OISA are emphasized mainly OISA design methods; consequently, they are devoted to minimizing dimensions and maximizing driving magnetic force with low power consumption. Although two proportional-integral-derivative controllers and lead-lag compensators have been proposed to position dual axes of OISA in a POS, they lack robustness to compensate nonuniform friction, system uncertainty, and external disturbance. Therefore, this work aims at the sliding mode control (SMC) using virtual eigenvalue method to achieve fast time response and accurate position despite vibration from external jitter and friction of a compact OISA. The sliding surface can be reached in finite time to match disturbance. Accordingly, the SMC algorithm works well despite system uncertainty and external disturbance, and then the time response of simulation and experiment are matched. In consequence, the settling time of dual axes are converged within 0.2 s when the dual axes of movable platform of a compact OISA move at 0.5 mm stroke in a POS.