An Orienting Robot for Feeding Workpieces Stored in Bins

A robot system has been tested which can acquire a class of workpieces that are unoriented in bins and transport them, one at a time, to a destination with the proper orientation. This kind of robot has numerous applications in industries which manufacture discrete-part products in batches. A variety of approaches to the design of an orienting robot have been identified. For acquisition, gripper design and vision algorithms should be considered together. A vacuum gripper which adapts to surface angle and an algorithm which finds the center of smooth regions in the bin image have been shown to form an effective combination. Knowledge of the position and orientation of the workpieces near the top of the bin is not necessary for acquisition. Collisions with workpieces in the bin whose poses are not known can be avoided by having the gripper follow a line of sight approach path. To simplify the computation of workpiece orientation, it was found to be useful to employ a gripper which locked a workpiece in one of a finite number of states and which did not obscure the workpiece. For an orienting robot which is designed to service a variety of different workpieces, using an arm with six degrees of freedom greatly facilitates workpiece transportation.