Voice coil motor-driven multi-DOF compliant parallel micropositioning stage based on a large range beam-based spherical hinge and fully symmetrical layout

Abstract

With the recent rapid developments in the field of precision engineering, demand for the large range multi-degrees-of-freedom (DOF) micropositioning stage has increased significantly. In this paper, to solve the problems of small motion range, local stress concentration, and low motion accuracy caused by the parasitic motion of the traditional flexure hinge in the multi-DOF micropositioning stage, we first propose a type of large-range beam-based flexure spherical hinge (BFSH). Subsequently, based on the proposed BFSH, a large range 3-DOF θxθyz spatial micropositioning stage driven by the voice coil motor is designed employing parallel branch chains and a fully symmetrical layout. This arrangement realizes theoretical motion decoupling in structural design. Furthermore, we use the geometric method to derive kinematic equations of the moving platform, which are used as the decoupling matrix of the control loop. Based on the compliance matrix method and Lagrange’s method, the compliance matrix model of the BFSH, the 3-DOF micropositioning stage, and the stage dynamic model are determined respectively. Additionally, finite element analysis and experimental tests are conducted to verify the accuracy of the analytical model and assess the static and dynamic performance of the designed 3-DOF stage. Moreover, a fractional order phase advanced proportional integral controller is designed for closed-loop control to track the sinusoidal trajectory and spherical trajectory. The results reveal that the stage can achieve the desired large workspace of ± 21.5 mrad × ± 20.3 mrad × ± 3.23 mm, as well as excellent decoupling and trajectory tracking performance.