Design, Fabrication, and Robust Control of Miniaturized Optical Image Stabilizers

3D printing and moulding (3DPM) method is applied to the fabrication of a miniature magnetic actuator for optical image stabilization (OIS) applications. Polydimethylsiloxane (PDMS) and strontium ferrite (SrFe) nano powder are used as the main structural materials. Young’s modulus and the magnetization of the material with SrFe-doping ratios ranging from 20 to 60 % by weight are characterized. The actuator, consisting of four coils, an actuating plate, and a base supporter, is assembled and tested with a laser Doppler velocimetry (LDV) system. A tilting angle of 0.6∘ is achieved with the application of 500 mA (50 turns/9 mm long coils). A Taguchi’s orthogonal experimental design is used in the finite element analysis (FEA) simulation to examine the effect of dimension variations on the eigenfrequencies. The frequency response of the actuator is characterized, and the experimental results match with the simulation results between 1 and 450 Hz showing less than 5 % errors and bandwidth of around 56 Hz. A series of replica experiments are also performed and analyzed. Additionally, unavoidable product variabilities in the batch fabrication of miniature actuators are discussed, and the application of robust control to deal with such variations is proposed.