Design and Analysis of New Large-Range XY Compliant Parallel Micromanipulators

Abstract

The need for a compliant parallel micromanipulator (CPM) providing large motion range and high precision is increasing. Existing CPMs vary in constraint configurations and therefore it is necessary to verify/compare their characteristics. This paper compares three kinds of typical over-constrained CPMs, and derives their theoretical compliance matrix models pointing out constraint characteristics of the three kinematic configurations. Then the three CPMs are analyzed with FEA (finite element analysis), and results illustrate that the theoretical compliance matrix models are close to their FEA models. Moreover, cross-axis coupling along two motion axes (X&Y), parasitic motion and compliance fluctuation of motion stages are described in details. Through analyzing the FEA results, we present an improved CPM with a mirror-symmetry structure and redundant-constraint characteristic which can effectively constrain in-plane yaw and cross-axis coupling. It is shown that the improved CPM presented in this paper has a series of merits: large motion range up to 10mm×10mm in the dimension of 311mm×311mm×24mm, small compliance fluctuation (only 37.32% of that of the initial model), a smaller cross-axis coupling (only 24.39% of that of the initial model generated by a single-axis 5mm driving), a smaller in-plane parasitic yaw (only 53.57% of that of the initial model generated by double-axis 5mm driving).