Ultrasonic Location Measurement for Fast Robot Control: A Transputer-Based Environment

The predominant form of operation for the presently available robot manipulators has been to teach the desired motion in an pre-programmed manner. However, the new generation of industrial robots are required to have a greater interactive ability for sensing the outside world, hence being able to function more satisfactorily in integrated automated environments. This paper presents an efficient position measurement device that gives the position and orientation of the robot end effector in real-time. An array of ultrasonic transmitters are employed along with multiple receivers to cover the required working area, thus avoiding the hazards of the presence of obstacles. Furthermore, a distributed form of the proposed algorithm has been developed on a multiprocessor system, which provides the equivalent joint-space configurations needed by the controller loops, while checking for the problems of redundant positions and singularities. The proposed system has been found to be able to track the desired trajectory at a frequency of (4.35KHz), with the distributed algorithm implemented by a network of 12 T800 transputers. In addition, a case study has been constructed for the PUMA 560 robot manipulator which shows the efficiency of the system/