Structural Synthesis of Parallel Linkages by Multibody Systems Method

Abstract

A large variety of methods are mentioned in literature for the structural analysis and conception of parallel linkages, applicable to planar and/or spatial mechanisms developed for various applications as manipulators-robots, guiding mechanisms for car wheels and axle, solar tracking systems. Modern design requires today a unitary description of all the mechanisms in a product (including linkages) for complex simulation and optimization on software platforms. This paper proposes a seven steps general method for the parallel linkages’ structural analysis and synthesis, considered as Multibody Systems. The method is based on the concept that describes a mechanism by a minimum number of bodies. Using as input data the application area, the motion space, the mechanism mobility and the type of joints, all possible fundamental multibody chains are obtained and, based on, the corresponding mechanisms. The method is described in detail and applied for the geometrical constraints of rotational (R), spherical (S), translational (T) and their combinations types. As example, a tracking system for a solar thermal platform, based on a parallel linkage with two degrees of freedom with R, S and T joints is presented.