Volume 20 Issue 11 - Publications Date: 1 November 2001
Trap Design for Vibratory Bowl Feeders
R-P. Berretty University of North Carolina at Chapel Hill, K. Goldberg University of California at Berkeley, M.H. Overmars and A.F. van der Stappen Utrecht University, the Netherlands
The vibratory bowl feeder is the oldest and still most common approach to the automated feeding (orienting) of industrial parts. In this paper, the authors consider a class of vibratory bowl filters that can be described by removing polygonal sections from the track; this class of filters is referred to as traps. For an n-sided polygonal part and an m-sided polygonal trap, an O(n2m log n) algorithm is given to decide whether the part in a specific orientation will safely move across the trap or will fall through the trap and thus be filtered out. For an n-sided convex polygonal part and m-sided convex polygonal trap, this bound is improved to O((n + m) log n). Furthermore, the authors show how to design various trap shapes, ranging from simple traps to general polygons, which will filter out all but one of the different stable orientations of a given part. Although the runtimes of the design algorithms are exponential in the number of trap parameters, many industrial part feeders use few-parameter traps (balconies, canyons, slots); in these cases, the running times of the algorithms range from linear to low-degree polynomial.
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