Design and experiment of a 3 DOF parallel micro-mechanism utilizing flexure hinges

Abstract

A planar 3 DOF parallel-type micro-positioning mechanism is designed with the intention of accurate flexure hinge modeling. For this, a preliminary kinematic analysis that includes inverse kinematics, internal kinematics, and analytic stiffness modeling referenced to the task coordinate is presented. First, the revolute type of a 1 DOF flexure hinge is considered. The simulation result based on FEM, however, is not coincident to the analytic result. This is due to the minor axial elongation along the link direction that keeps the mechanism from precise positioning. To cope with this problem, a 2 DOF flexure hinge model that includes this additional motion degree as a prismatic joint is employed in part. On the basis of this model, the positional accuracy is ensured. The effectiveness of this accurate model is shown through both simulation and experimentation This work emphasizes that the precise modeling of a flexure hinge is significant to guarantee the positional accuracy of parallel micro-mechanisms using flexure hinge.