FEEDBACK CONTROL OF INDUSTRIAL ROBOT MANIPULATORS

THE PRESENT BISTATIC OPTICAL STEREOSCOPIC SYSTEMS USING TRIANGULATION APPROACH HAVE ONE SERIOUS DRAWBACK: AT SHORT DISTANCES BOTH SENSORS MAY NOT NECESSARILY BE EXPOSED TO THESAME REGIONS OF A COMPLEX OBJECT. A SINGLE ULTRASONIC SENSOR IS SUFFICIENT TO MEASURE DISTANCES TO AN OBJECT. ADVANTAGES OF ULTRASONIC SENSOR ARE ITS LOW COST AND HIGH PRECISION OF SHORT RANGE MEASUREMENTS. EFFECTIVE USE OF ULTRASONIC SENSOR SYSTEMS WILL ALLOW INEXPENSIVE ROBOTS TO HANDLE IMPRECISELY POSITIONED PARTS, WELD, INSPECT, AND PERFORM FACTORY ASSEMBLY TASKS. WE PROPOSE TO BUILD AN ARRAY OF ULTRASONIC TRANSDUCERS, MOUNT IT ON THE WRIST OF A ROBOT, AND INTEGRATE IT WITH THE MANIPULATOR. THE ACOUSTIC BEAMS WILL BE ELECTRONICALLY STEERED AND FOCUSED. THE ELECTRONIC BEAM FOCUSING WILL IMPROVE THE ANGULAR RESOLUTION. A PARALLEL PROCESSING ARCHITECTURE IS PROPOSED TO PROCESS THE THREE-DIMENSIONAL IMAGES. COMPUTER INTEGRATION BETWEEN THE SENSOR ACQUIRED DATA AND THE MANIPULATOR JOINTS CONTROL INCLUDES MOTION-PATHPLANNING BLOCK AND COORDINATE TRANSFORMATION BLOCK. THIS UNIQUE TECHNICAL APPROACH ALLOWS THE SENSOR AND THE MANIPULATOR TO CARRY OUT EXTREMELY DEXTEROUS WORK WHICH DEMANDS PRECISE POSITION AND MOTION PATH CONTROL OF THE ROBOT HAND AND/OR ROBOT HAND-HELD TOOLS WITH RESPECT TO WORKPLECE.