Flexures for large stroke electrostatic comb-drive actuators

Flexure mechanisms are commonly used in electrostatic comb-drive actuators to achieve large and stable strokes. The stable stroke length depends upon the spring stiffness ratio of the flexure mechanism, the initial finger overlap between the comb-fingers, and the gap between comb fingers. In this work, we present an improved tilted flexure mechanism (ITFF) for achieving large unidirectional stroke length and stable motion. The flexure mechanisms are studied using finite element analysis (FEA) with geometric non-linearities taken into consideration. The results demonstrate that large stroke length can be achieved using improved tilted folded beam flexure (ITFF) as compared to commonly used double parallelogram flexure (DP-DP). The results are also compared with tilted folded flexure (TFF), and the results show an increase in stable stroke length.