Impact of Vane Size and Separation on Radiometric Forces for Microactuation (Preprint)
AIR FORCE RESEARCH LAB EDWARDS AFB CA
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A kinetic approach is used to study the feasibility of increasing the efficiency of microactuators that use radiometric force through etching holes in a single radiometer vane. It has been shown that a radiometer that consists of small vanes is capable of producing at least an order of magnitude larger force than a single vane radiometer that takes up the same area. The optimum gap between the vanes is found to be slightly smaller than the vane size, with the optimum Knudsen number of about 0.05 based on the vane height. Several competing processes have been suggested for the actuation of micromechanical devices. Electrostatic micro-actuators have been suggested1, 2 where a potential difference between two sets of combs produces a force generated by the associated electric field. Generally, electrostatic micro-actuators are linear drive devices and are not well suited for rotational operation. Piezoelectric devices3 have been considered where an electric field applied to a material causes mechanical deformation in the material. The piezoelectric effect typically produces very small material deflections however, they can have a very fast actuation frequency from the kHz up to the MHz range. Electrically conducting polymers4 can be used to change the volume of a material to provide more actuation distance than a typical piezoelectric material with lower applied voltages.
- Electricity and Magnetism