Research on a 3-DOF Compliant Precision Positioning Stage Based on Piezoelectric Actuators

Precision positioning with multiple degree-of-freedoms (DOFs) is the core technology of nanometer manufacturing equipment. In this paper, a 3-DOFs monolithic parallel compliant manipulator is designed for relieving the conflicts among large workspace, high precision positioning and multi-DOFs. The 3-DOFs compliant micro-positioning manipulator has parallel structure and is composed of a static platform, a moving platform and three kinematic chains. Three kinematic chains are arranged symmetrically along the center of the moving platform with 120 degrees, and each chain is actuated by a piezoelectric ceramic actuator through a variable cross-section symmetrical four-bar mechanism with low coupling and better sensitivity. Flexure hinges are utilized as the revolute joints to provide smooth and high accurate motion with nanometer level resolution. Based on the "pseudo-rigid-body model" method, the inverse kinematics model and dynamic model of the compliant manipulator are established. Finally, the natural frequency of the 3-DOFs compliant micro-positioning manipulator is obtained by the ANSYS software.