A Rotary Microactuator Supported on Encapsulated Microball Bearings using an Electro-Pneumatic Thrust Balance

The development of a rotary microactuator supported on encapsulated microball bearings and driven by electro-pneumatic actuation is reported. The encapsulated bearing provides full support to an encased rotor, while an electro-pneumatic thrust balance is used to minimize normal load, and therefore bearing friction. Experimental results show excellent agreement with predictions, demonstrating the ability to operate at optimal normal loads up to 2000 rpm. This is the first demonstration of a ball bearing supported electrostatic microactuator with a fully encased rotor, capable of being integrated within practical microsystems. The fully-supported rotor allows for direct mechanical attachment or reliable interaction with external media and is a necessity for useful implementation.