A Study on Fluid Driven Microactuator

This paper describes a new design of a fluid driven micro-actuator which can be fabricated by anisotropic etching of single crystalline silicon. The actuator has a four-way valve to regulate the work fluid and a differential piston to generate linear force. First, fundamental flow characteristics are analyzed theoretically when the fluid flows in simple channels which have rectangular and trapezoidal cross section. Applicability of the Navier-Stokes equation assumed in the analysis is confirmed about the specific dimensions used in the actuator design by actual flow measurement. Then proposed actuator is examined separately on four constituent parts by numerical resolution of the N. S. equation. Consequently the results are integrated to estimate the output of the actuator. The design parameters of piston-casing clearance, piston width and casing height are investigated to evaluate the effect on the output. Finally the output characteristics are compared with that of an electrostatic actuator. The output and the one for unit area are expected to be a hundred times and ten times as large as those of the electrostatic actuator respectively.