Co-ordinate determination and performance analysis for robot manipulators and guided vehicles

Describes a technique to determine and to track the three-dimensional `world´ co-ordinates of a point in space, in relative to some defined datum. The work was initiated in order to track the location of a robot manipulator end effector, but has relevance to automatic guided vehicles and other applications. A prototype system has been built and evaluated, and has been used successfully to track the tip of a robot manipulator arm moving at velocities of up to 2 m/s within a working envelope consisting of a cube of side 2 m. Measurement resolution of 0.5 mm was obtained, and a sampling rate of 300 Hz was achieved, by the use of real-time software within the measurement system. The coordinates and the velocity outputs are computed in only 1.2 ms. As far as robot manipulators are concerned, the technique provides accurate tracking of end-effector position, which can be used both for evaluating the dynamic performance of existing controllers and for the synthesis of new forms of control