Orienting small parts with vibration: A passive juggling strategy.

Abstract

Motivated by the problems of flexible manufacturing and parts feeding in sensor-less assembly, we propose a flat, level vibrating table as a means of orienting small parts for assembly. We demonstrate that a passive vibration strategy can bring a 1 degree of freedom bouncing ball to a specified periodic trajectory from all initial conditions. We examine the utility of catching and tossing the ball on the moving table, and demonstrate that such sticking solutions are locally attracting. The sticking strategy is extended to a shape that is free to rotate. Properties of sticking are exploited to partially control time of flight and rotational velocity during flight, which leads to a ratchet strategy in which the part tends to rotate in a consistent direction. A procedure for tuning the ratchet parameters is proposed, and numeric simulations suggest that the tuned system can reorient the part to a known orientation from all initial conditions. When extended to 3 degrees of freedom, simulations suggest that the same ratchet strategy and tuning procedure bring the state of the part to a known orientation.