Abstract
We report on a position measurement system for a mobile miniature robot using moving marks. Three lasers mounted on three linear stages are used as moving marks, and three position sensitive detectors (PSDs) are installed on the robot. The position of the miniature robot is measured by the laser position and the PSD output. The position of the lasers determines the macro position of the robot, and the output of the PSDs detects the micro displacement of the robot. By using the moving marks, the measurement system can avoid an obstacle on the laser beam path.