Analysis and optimal design of a spherical parallel manipulator with three rotational degrees of freedom

Abstract

Spherical parallel manipulators with three rotational degrees of freedom have been widely researched for a long time, and many mechanisms have been proposed and designed for some specific tasks. In this paper, the concept design of a spherical parallel manipulator with three rotational degrees of freedom is presented. The optimal design of this type of parallel mechanism with a 3SPU-1S kinematic chain is detailed which can act as a haptic device, and the purpose of the optimal design is to find a set of parameters that achieve a relatively good performance in terms of three important indexes, that is, to define the tradeoff among the workspace capabilities, dexterity and stiffness. First, the inverse kinematic equations and Jacobian matrix of the spherical parallel manipulator are formulated, which is the necessary for subsequent analysis. Then, three important performance is analyzed. Finally, the dimensional synthesis based on a compound performance index is introduced and simulation results are obtained. © Springer-Verlag Berlin Heidelberg 2013.