Fluidic actuation by electrorheological microdevices

Electrorheological microdevices with planar and cylindrical geometry have b een developed for control of fluidic microactuators. The devices consist of capacitor elements of 50 mu m gap size, which confine a flow channel of 10 -20 mm length. A homogeneous electrorheological fluid (ERF) is used for ope ration of the devices displaying a viscosity change of about 25 for a volta ge of 500 V at a pressure difference of 2000 hPa. The maximum control power is 0.65 mW. Switching times are in the order of 50 ms. The microdevices ha ve been used to control the motion of a micropiston with 1 mm stroke fabric ated by the LIGA technology. (C) 2000 Elsevier Science Ltd. All rights rese rved.