A Novel Actuator-Internal Micro/Nano Positioning Stage With an Arch-Shape Bridge-Type Amplifier

This paper presents a novel actuator-internal two degree-of-freedom (2-DOF) micro/nano positioning stage actuated by piezoelectric (PZT) actuators, which can be used as a fine actuation part in dual-stage system. To compensate the positioning error of coarse stage and achieve a large motion stroke, a symmetrical structure with an arch-shape bridge-type amplifier based on single notch circular flexure hinges is proposed and utilized in the positioning stage. Due to the compound bridge arm configuration and compact flexure hinge structure, the amplification mechanism can realize high lateral stiffness and compact structure simultaneously, which is of great importance to protect PZT actuators. The amplification mechanism is integrated into the decoupling mechanism to improve compactness, and to produce decoupled motion in X-and Y-axes. An analytical model is established to explore the static and dynamic characteristics, and the geometric parameters are optimized. The performance of the positioning stage is evaluated through finite element analysis and experimental test. The results indicate that the stage can implement 2-DOF decoupled motion with a travel range of 55.4 x 53.2 mu m(2), and the motion resolution is 8 nm. The stage can be used in probe tip-based micro/nano scratching.