A single-layer PDMS-on-silicon hybrid microactuator with multi-axis out-of-plane motion capabilities - Part I: Design and analysis

This paper proposes a new single-layer electrostatic microactuator design that generates three-axis motion resulting in vertical translation and out-of-plane tilting. The new actuator design combines a micrometer-scale three-dimensional (3-D) polydimethylsiloxane (PDMS) structure fabricated using soft lithography with comb drives processed using a single mask on a silicon-on-insulator (SOI) wafer. The multi-axis actuation capability of the proposed actuator is enabled by coupling the in-plane actuation motion of the comb drives with the elastic bending of PDMS flexural microjoints. To predict the static and dynamic performance of the actuator, this paper develops a four-bar-linkage model and applies Lagrangian dynamics theory. The developed analytical model is validated using finite element analysis (FEA) and allows us to perform parametric design of the actuator. The analysis indicates that the proposed PDMS-on-silicon hybrid actuator can yield the desired multi-axis actuation capability with a dynamic bandwidth as large as 5 kHz.