Minimal Trap Design

This paper addresses the issue of trap design for sensor-less automated assembly. First, we present a simple algorithm that determines in O(nmm(nm) log(nm)) time whether an n-sided polygonal part will fall through an m-sided polygonal trap. We then introduce the notion of a minimal trap for a polygonal part, and develop an O(n 4+") algorithm that designs a family of minimal feeders built from these traps. The algorithm is complete in the sense that we can always nd a feeder, provided that one exists that rejects and supports the appropriate poses of the part with a little tolerance. Finally , we describe how to modify our minimal traps to ensure the part will actually fall through.