Dimensional synthesis method of parallel manipulators based on the principle component analysis

Abstract

The results of dimensional synthesis have an important influence on the comprehensive performance of parallel manipulators (PMs). Usually, dimensional synthesis for PMs should take multiple performance indices such as kinematic index, stiffness index, etc., into consideration. It is difficult to establish a comprehensive performance index with clear explanation since the non-uniform dimensions of multiple indices. This paper presents a dimensional synthesis method for PMs based on the principle component analysis. For p performance indices that are concerned, m (m < p) principle components are identified to achieve dimensionally reduction. Then a reasonable explanation for the meaning of principle components is provided using factor analysis method. A comprehensive performance index is finally presented, and its weight factors are clearly explained. An intelligent algorithm is adopted for obtaining the optimal comprehensive performance. Meanwhile, a bisection method is employed to accelerate the detection of boundaries of the regular workspace to improve the computational cost of objective functions. A 6-DOFs 6PSS PM is taken as an example to verify the proposed method (where P is a prismatic joint and S is a spherical joint).