Design and Analysis of a Flexure-Based Parallel XY Stage Driven by Differential Piezo Forces

The non-bipolar operation of a stack-type piezo actuator causes non-bidirectional motion of the piezo-driven stage. This paper proposes a piezo-driven XY stage with a monolithic compliant parallel mechanism for fully bidirectional operation. Four prismatic-prismatic flexure-based joint chains are arranged antagonistically at the four sides of a target platform of the XY stage. The motion of each axis is conducted by differential force between piezo actuators in two actuating mechanisms arranged at both sides of a target platform along the same axis. Due to this antagonistic arrangement, the home position of the target platform is at the center position of the full operating range, and the target platform is movable along the positive and negative directions from the home position. Mathematical modeling of the proposed compliant mechanism is performed using a matrix-based equation of motion. The compliant mechanism is designed to satisfy design constraints using the mathematical model, and the designed mechanism is then analyzed using the Finite Element Method (FEM). The proposed bidirectional operation of the piezo-driven XY stage is demonstrated and the performance of the stage is subsequently described in terms of the response time, bandwidth and resolution.