Manufacturing and Reliability of Three-Dimensional Micro-Mechanical Actuators

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This grant provides funding for the development of micro-actuators, e.g., micro-motor, dynamic micro-gas bearing micro-continuously-variable speed-reducers. Inasmuch as magnetic fields, difficult to contain, have limited micro-scale use, two electrostatic motor drive concepts will be developed: (1) Variable Capacitance Motor - Variable capacitance motor minimizes energy of electric field in an air gap field that can change geometry. Rotor electrodes seek positions relative to stator electrodes of least potential energy stored in the electric field of an air gap between the rotor and stator. (2) Induced Charge Motor - Induced charge motor is based on a concept of induced polarization of charges of material in the motor creating a secondary electric field which aligns in a primary field. This variant of drive is the electric field analogy to an induction motor. To avoid stiction, contact between surfaces in relative motion must be avoided as in bearings. Among other concepts, micro-gas-bearings will be developed. Micro-grooves built into the shaft part of the motor will pump air or gas and build-up films that keep the shaft from touching the bearing and housing. In order to avoid stiction for start-stop, the bearing housing will be suitable coated with a thin film lubricant. For the above, and other actuators, advanced science-based modeling methods will be developed for underpinning design.If successful, the results of this research will lead to new methods in the relatively new arena of manufacturing in the micro-scale of three-dimensional mechanical components needed for various actuators. In developing the methods, emphasis will be given to reliability in the use of components in actuators. Envisioned are applications of actuators in bio-medical, aerospace, as well as other consumer products for which micro-size is paramount. Of course the use of micro-size actuators has the additional advantage of being environmentally friendly.