Micro Electro Mechanical Actuator Arrays

Joint work with Bruce Donald, Noel MacDonald, and Robert Mihailovich.
Our actuators are based on microfabricated torsional resonators [5], rectangular grids etched out of single-crystal silicon [6] and suspended by two rods that act as torsional springs. When an AC voltage is applied between grid and adjacent electrodes, the grid oscillates at resonance frequencies in the high kHz range. The edges of the grid reach deflections of several micrometers.

Micro Actuator Array (Spring '95)

By introducing asymmetries into the resonator grid (such as placing the torsional rods off the center of the grid, or adding poles on one side of the grid) anisotropic lateral forces are generated, thus achieving a motion bias for the object on top of the actuator.

Micro Actuator Detail (Spring '95)

Each actuator can generate motion in one specific direction if it is activated; otherwise it acts as a passive frictional contact. The combination and selective activation of several actuators with different motion bias allows us to generate various motions in the plane. The figures above show such a "motion pixel," as well as an actuator array.

Micro Motion Pixel (Spring '94)

A thorough analysis and dynamic simulation of these devices has been performed by D. Reznik, Stan Brown, and John Canny at UC Berkeley.

Videos:

Publications:

  1. K.-F. Böhringer, B. R. Donald, and N. C. MacDonald, Upper and Lower Bounds for Programmable Vector Fields with Applications to MEMS and Vibratory Plate Parts Feeders, Workshop on Algorithmic Foundations of Robotics (WAFR), Toulouse, France (July, 1996).
  2. K.-F. Böhringer, B. R. Donald, and N. C. MacDonald, Single-Crystal Silicon Actuator Arrays for Micro Manipulation Tasks, IEEE Workshop on Micro Electro Mechanical Systems (MEMS), San Diego, California (February 1996).
  3. K.-F. Böhringer, B. R. Donald, R. Mihailovich, and N. C. MacDonald, Sensorless Manipulation Using Massively Parallel Microfabricated Actuator Arrays, Proc. IEEE International Conference on Robotics and Automation (ICRA), San Diego, California (May 1994). Nominated for Best Conference Paper Award.
  4. K.-F. Böhringer, B. R. Donald, R. Mihailovich, and N. C. MacDonald, A Theory of Manipulation and Control for Microfabricated Actuator Arrays, Proc. IEEE Workshop on Micro Electro Mechanical Systems (MEMS), Oiso, Japan (January 1994).

    Also of interest:

  5. R. E. Mihailovich, Z. L. Zhang, K. A. Shaw, and N. C. MacDonald, Single-Crystal Silicon Torsional Resonators, Proc. IEEE Workshop on Micro Electro Mechanical Systems (MEMS), Fort Lauderdale, Florida (February 1993).
  6. Z. L. Zhang and N. C. MacDonald, An RIE Process for Submicron, Silicon Electromechanical Structures, Journal of Micromechanics and Microengineering 2(1):31-38 (March 1992).

karl@cs.cornell.edu