Micro-motion detection of the 3-DOF precision positioning stage based on iterative optimized template matching.

This study presents a method for micro-motion detection of the three-degrees-of-freedom (3-DOF; x, y, θz) precision positioning stage (PPS) based on iterative optimized template matching (IOTM). In this method, a micro-vision system (MVS) is constructed and employed to capture magnified images of the measured PPS's surface with high quality. In addition, an efficient and accurate IOTM algorithm, which includes a pyramid hierarchical matching step for generating the initial guess and an iterative searching step for 3-DOF fine matching, is proposed to detect the micro-motion of the 3-DOF PPS. The simulation results show that the locating accuracy of the translation component (TC) and rotation component of this algorithm can respectively reach 0.01 pixels and 0.01 deg when the image quality is high and the initial guess is close to the real location. Measurement tests of a nano-PPS verify that the proposed method is practical and effective for 3-DOF micro-motion detection and the absolute accuracy of the TC of the MVS can easily reach the nanometer level.