Design and analysis of a 2-DOF planar nano-positioner with low parasitic rotation

This paper presents the design processes and performance of a new piezoactuated nano-positioner with low parasitic rotation. The flexure-based stage is composed of two symmetric flexure guiding mechanisms and two piezo stack actuators (PSAs) which have a 45 degree angle with X and Y directions. By analyzing the layout of the stage with kinematics and finite element analysis (FEA) results, it shows that this novel design offers a characteristic of low parasitic rotation. Analytical models of PSAs and stage are derived to assess the performances and to decide the parameters of geometry sizes of the hinge and the stage, total stroke, maximum von-Mises stress, and lifetime. A prototype of the stage is then fabricated, and its performances are tested. Two laser displacement sensors and PID control method are used to achieve a feedback control of the system. Experimental results reveal that the stage has stroke of 500 μm × 500 μm, resolution of 10 nm, and maximum parasitic rotation of 0.48 arc sec under stroke of ±50 μm.