General method of structural synthesis of parallel mechanisms

Abstract

This paper presents a method of the structural synthesis of spatial or planar parallel mechanisms. The method exploits the combined strengths of the Baranov method and the intermediate chain method. It makes possible to create complete sets of parallel mechanism solutions. Relations for the number and structure of branches are provided. The successive steps in the procedure for generating a structural form of a closed branch, the opening of the branch, the way of constructing a parallel mechanism from branches with negative and zero degree of freedom (DoF) and the connection of the drives separated from the branches are described.The proposed method of structural synthesis was applied to generate a complete set of branch solutions, written using numerals representing the number of links in a branch and the number of kinematic pairs of proper class, and to demonstrate the possibilities of creating mechanisms with a different number of branches. The end result was a complete set of possible spatial parallel mechanism solutions for the required mobility.