Active Touch Sensing

Abstract : The mechanical hand of the future will roll a screw between its fingers and sense, by touch, which end is which. This paper describes a step toward such a manipulator -- a robot finger that is used to recognize small objects by touch. The device incorporates a novel imaging tactile sensor -- an artificial skin with hundreds of pressure sensors in a space the size of a finger tip. The sensor is mounted on a tendon-actuated mechanical finger, similar in size and range of motion to a human index finger. A program controls the finger, using it to press and probe the object placed in front of it. Based on how the object feels, the program guesses its shape and orientation and then uses the finger to test and refine the hypothesis. The device is programmed to recognize commonly used fastening devices-nuts, bolts, flat washers, lock washers, dowel pins, cotter pins, and set screws.