Design and development of a 2R1T flexure mechanism

Abstract

Flexure-based parallel mechanisms (FPMs) are popular mechanisms used in precision engineering due to precise, accurate, and repeatable small-scale displacements they provide. They consist of an end effector articulated by one or more sub-chains. Of the many different configurations FPM has, Z-θX-θY configuration has been selected for its widespread use in manufacturing industry due to its suitability for machining complex curved surface. Several optimization methods for enhancing the end-effector’s stiffness and dynamic properties exist, such as homogeneous, solid isotropic material with penalization (SIMP), level set based method, etc. Most of these design methods consist of topological optimization which plays a significant part in altering the sub-chains’ stiffness and dynamic properties. However, these methods have their limitations. To address this, a novel method in topological optimization is introduced in this study to counteract the limitations. This method essentially employs 2-D Fourier series representation of the structure to undergo topological optimization via genetic algorithm by treating the stiffness properties of the sub-chains with an objective function, and hence ultimately attaining an optimized topology. The novel method is studied and utilized, and a resulting FPM with translational and rotational stiffness ratios of 7 and 4, respectively, is developed.