DEVELOPMENT OF A FLUID-DRIVEN MICROACTUATOR

In this paper we describe a new design of a fluid-driven microactuator which comprises a planar piston, a four-way control valve, and a mech anical feedback system that controls the output in accordance with an input displacement. Merits of this design are expected in terms of out put density, scalability, and feedback ability realized with no electr onic devices. Fabrication processes of the microactuator include bulk micromachining of two sheets of silicon substrate and their assembly b y electrostatic bonding to glass plates. The output characteristics we re measured while compressed air was supplied. Generated output force showed an almost linear relationship to supplied pressure and to valve displacement. However, the magnitude was asymmetric in terms of drive n directions, which resulted from geometrical configuration essentiall y introduced by an anisotropic etching of the silicon substrate. The p osition of the output shaft was sufficiently controlled with a designe d magnification factor multiplied to the input displacement in both st atic and dynamic senses.