A Computer-Controlled Rotating-Belt Hand for Object Orientation

Semiautomated tasks frequently require humans to perform highly repetitive boring jobs such as placing objects into machine fixtures. The use of an electromechanical hand design is discussed which may operate in conjunction with industrial robots, part feeders, and minicomputers to perform some of these jobs. Flexibility is achieved with the same hardware by using different control algorithms for differently shaped objects. The design principle which permits simplicity is that the motion which is used to adjust object orientation is also instrumental in the detection of orientation. A ``hand´´ was built and a control algorithm to orient a specific object was developed. The control algorithm first recognizes orientation by computing asymmetries and then conditionally adjusts a positional servomechanism in the hand to bring the object to a standard orientation. Tests verified hand performance and indicated restrictions on object shape. Regardless of the initial angle (360° range) about the uncontrolled axis, the computer-controlled hand adjusted this angle to within ±3°. For the prototype, object shape is primarily restricted by the requirement that objects must have their principal axes directed to within ±10° by conventional part feeders and sorters.