Vision-Based Feedback Strategy for Controlled Pushing of Microparticles

N.A. Lynch, C.D. Onal, E. Schuster and M. Sitti

Journal of Micro-Nano Mechatronics, Volume 4, Issue 1, pp 73-83, November 2008

Abstract

A strategy for controlled pushing is presented for microassembly of 4.5 micro-m polystyrene particles on a flat glass substrate using an atomic force microscope probe tip. Real-time vision based feedback from a CCD camera mounted to a high resolution optical microscope is used to track particle positions relative to the tip and target position. Tip-particle system is modeled in 2D as a non-holonomic differential drive robot. Effectiveness of the controller is demonstrated through experiments performed using a single goal position as well as linking a series of target positions to form a single complex trajectory. Cell decomposition and wavefront expansion algorithms are implemented to autonomously locate a navigable path to a specified target position. Control strategy alleviates problem of slipping and spinning during pushing.