Design, fabrication and testing of a novel symmetrical 3-DOF large-stroke parallel micro/nano-positioning stage

Limited travel stroke constrains the application of existing XYZ parallel micro/nano-positioning stages. In this paper, a novel parallel-kinematic symmetrical micro/nano-positioning stage is proposed to enlarge the travel range with a compact physical size. For a large-stroke parallel stage, the cross-axis motion increases the difficulty of closed-loop control process. The motions of the parallel stage on different axes are decoupled by employing I-shaped flexure hinges in this work. In order to obtain a large input displacement for actuating the stage, three voice coil motors (VCM) are adopted. In view of the lower output force of the VCM, the guiding flexure mechanism is designed with an optimized cross-sectional dimension. To verify the performance of the stage, analytical modeling and simulation study are carried out. A prototype stage is fabricated for experimental studies. Results show that the designed parallel micro/nano-positioning stage owns a three-degree-of-freedom motion workspace of 2.22 mm  ×  2.22 mm  ×  1.81 mm with an overall size of 176 mm  ×  176 mm  ×  198 mm, which is more compact than existing symmetrical designs containing the actuators. Moreover, the symmetrical design enables a low crosstalk of 1.7% among the three working axes.