Sensorless Manipulation With Micro Actuator Arrays

Joint work with Bruce Donald, Robert Mihailovich, and Noel MacDonald.
We investigate manipulation tasks with arrays of microelectromechanical structures (MEMS). We have developed a model for the mechanics of microactuators and a theory of sensorless, parallel manipulation, and we describe efficient algorithms for their evaluation.

Simple actuator control strategies can be used to uniquely align a part up to symmetry without sensor feedback. This theory is applicable to a wide range of microactuator arrays. Our actuators are arrays of oscillating SCS structures fabricated in an IC-compatible process.

Sensorless Orientation

The above figure shows a two-step part alignment plan for two different initial part placements. In each step the actuators push perpendicularly towards a straight line. Based on related work on robot grippers [6] we show that for any part there exists a short sequence of such lines such that the part gets aligned uniquely up to symmetry.

Sensorless Sorting

In this figure we use a two-step sensorless plan to separate smaller objects from larger ones.

Recently we have investigated upper and lower bounds on these strategies [1,5], and we have discovered a pathological part that cannot be aligned with such sensorless strategies.

A thorough analysis and dynamic simulation of these strategies 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, What Programmable Vector Fields Can (and Cannot) Do: Force Field Algorithms for MEMS and Vibratory Plate Parts Feeders, IEEE International Conference on Robotics and Automation (ICRA), Minneapolis, Minnesota (April 1996).
  3. 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).
  4. 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.
  5. 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:

  6. K. Y. Goldberg, Orienting Polygonal Parts Without Sensing, Algorithmica, 10(2/3/4):201-225, Springer Verlag (August / September / October 1993).

karl@cs.cornell.edu