Passive vibration isolation of flexure jointed hexapod: A geometry design method

Abstract

This paper presents the passive vibration isolation problem for a specific kind of Stewart Platform called flexure jointed hexapod (FJH). For purpose of analyzing the relationship between passive vibration isolation and parameters of the FJH, an existing dynamic model of the hexapod is re-cast appropriately to obtain the transfer function matrix from disturbance to generalized coordinates of the payload. Then, the system natural frequencies and the corresponding damping ratios are derived analytically. To guarantee the effective disturbance attenuation and isolation, a lower bound of the disturbance frequency with respect to the geometric parameters of the FJH is identified. Based on the identified sufficient conditions for disturbance isolation, a new design algorithm for geometry structure of the FJH and coefficients of the parallel spring-damping mechanism in struts is proposed. Finally, numerical simulation results are provided to demonstrate effectiveness of the proposed design algorithm.