Design and nonlinear modeling of a large-displacement XYZ flexure parallel mechanism with decoupled kinematic structure

Abstract

This article proposes an XYZ flexure parallel mechanism (FPM) with large displacement and decoupled kinematic structure. The motion range of the large-displacement FPM using notch hinges is more than 1mm and is achieved by assembling the typical large-displacement prismatic joints and a new large-displacement prismatic joint proposed in this article. Moreover, the decoupled XYZ stage has small cross-axis error and small parasitic rotation. An exact nonlinear modeling method for the typical prismatic joint and the new type of prismatic joint is presented. Using the proposed nonlinear method, the stiffness and dynamics of the XYZ FPM are studied. Comparison between the pseudo-rigid-body and the proposed nonlinear methods is performed on the prismatic joints and the XYZ FPM. To verify the proposed nonlinear modeling method, experiments are conducted to study the linear stiffness of the prismatic joint. The stiffness and the natural frequency of the XYZ FPM are also obtained from the experimental data. The cross-axis error and the parasitic rotation of the XYZ FPM are measured. The experimental results show that the proposed XYZ FPM achieves large displacement and decoupled motion, and the proposed nonlinear method is valid for the flexure mechanism.