Motion tracking of a part on a vibratory feeder

Abstract

A fast boundary extraction routine is first introduced to search a part of interest by investigating several scan lines. Once the first three boundary points of the part forming a seed segment are located, the boundary tracing and growing process can be quickly and accurately implemented inside a sequence of small regions. The pose vector [x~,y~,/spl theta/] that represents the location and orientation of the part is estimated based on the part's boundary information. The motion tracking procedure consists of four phases: 1) predict the next region that the part will appear using the previous and current pose vectors; 2) extract the part's boundary within the predicted region using the same boundary-extraction routine; 3) update the pose vector by calculating the new centroid and orientation; and 4) feed the new pose information to the controller to adjust the control signals. This prediction-searching-updating-feedback cycle is repeated until the part reaches its desired position with the desired orientation. The proposed algorithm is fast. Finally, the tracking speed and accuracy are evaluated.