Electrostatic Micro-Hydraulic Systems

MEMS micro-hydraulic structures for amplification of force or deflection are introduced. These structures are integrated with capacitances to form electrostatic micro-hydraulic actuators (EMA). Hydraulic amplification and liquid permittivity are used to create stand-alone, efficient, and large deflection, and high force actuators. Force is generated using electrostatics with no need for external pressure sources. Use of integrated electrostatic force significantly reduces the device size. Utilizing this concept, a micro-valve and two types of EMA micro-piston arrays (water-based and silicone oil-based) are fabricated and tested. The micro-valve can switch fluid flows with the pressure ranging from 10 to 50 kPa at a maximum flow conductance of 20.3 sccm at 10 kPa with an actuation voltage of 340 V
_DC
or 120 V
_AC
. The silicone oil based micro-hydraulic micro-piston array has shown a maximum out-of-plane deflection of about 100 μm at 210 V
_DC
, and a maximum bandwidth of about 5 Hz with a foot print size of 0.16 cm
²
and a maximum power consumption of 20 μW at 1 Hz. These devices are the smallest ever reported microhydraulic systems that include the actuation source.