A Large Range X-Y Parallel Micro-motion System with Optical Encoder Displacement Feedback

Linear optical encoders with a nano-resolution have been widely applied in various precision engineering fields for displacement feedback supporting micro/nano motions regulated by feedback control systems. However such sensing method is sensitive to assembly tolerance in the lateral motion (perpendicular to the primary direction), which limits its applications to single-axis motion systems or very small stroke multi-axis motion systems. In this paper, a large range X-Y parallel flexure-beam based micro-motion system is developed with an enhanced sensing framework employing two linear optical encoders to measure the two-axis large outputs. Meanwhile, both the open-loop and preliminary closed-loop experiments are conducted, demonstrating effectiveness of the proposed design and accurate sensing capability of the sensing framework.