Large range dual-axis micro-stage driven by electrostatic comb-drive actuators

This paper presents a micro XY stage that employs electrostatic comb-drive actuators and achieves a bi-directional displacement range greater than 225 µm per motion axis. The proposed XY stage design comprises four rigid stages (ground, motion stage, and two intermediate stages) interconnected via flexure modules. The motion stage, which has two translational degrees of freedom, is connected to two independent single degree of freedom intermediate stages via respective parallelogram (P) transmission flexures. The intermediate stages are connected to the ground via respective clamped paired double parallelogram (C-DP-DP) guidance flexures. The C-DP-DP flexure, unlike conventional flexures such as the paired double parallelogram flexure (DP-DP), provides high bearing direction stiffness (K_b) while maintaining low motion direction stiffness (K_m) over a large range of motion direction displacement. This helps delay the onset of sideways instability in the comb-drive actuators that are integrated with the intermediate stages, thereby offering a significantly greater actuation stroke compared to existing designs. The presented work includes closed-form stiffness analysis of the proposed micro-stage, finite elements simulation, and experimental measurements of its static and dynamic behavior. (paper)