Measurement System for Multiple Degrees of Freedom Moving Robot
Department of Precision Machinery Engineering, Faculty of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113 Japan
The multiple degrees of freedom (multi-DOF) moving robot and its measurement system have been developed realize a positioning system with high flexibility. The multi-DOF robot is driven by six piezo-electric devices; and it moves in two modes, an absolute motion mode and a relative motion mode. In the absolute motion mode, it walks on a surface plate by a two-dimensional inchworm method having 3-DOF, in X and Y directions and a rotation. After a frame body is fixed, a center table can be positioned on 6-DOF. For measuring its position, the novel position measurement system has been developed. It has two measurement modes; an absolute measurement mode and a relative measurement mode. In the absolute mode, the two-dimensional position of the robot can be calculated from the length of a laser interferometer and the angle of a tracking mirror. After the tracking mirror is fixed, the relative displacement of the center table is measured by the laser interferometer, and the position of a reflecting laser beam is measured on a Position Sensitive Detector (PSD). We conclude that the high flexibility positioning system can be realized using the multi-DOF robot and the measurement system.