Dimensional synthesis of a spatial 3-RPS parallel manipulator for a prescribed range of motion of spherical joints

This paper presents the dimensional synthesis of a 3-RPS (revolute–prismatic–spherical) parallel manipulator according to the limitation on the range of motion of the spherical joints. The synthesis of the manipulator is carried out using a hybrid optimization method called GA–simplex method. The architectural parameters of the manipulator are determined by considering the design problem as an optimization problem. The hybrid method first carries out the global search for the solution using genetic algorithm (GA) and then applies the simplex method for the local search. While determining the dimensions of the fixed platform, the physical constraints such as limitation on the range of motion of the spherical joints are considered to make the design practical. The procedure presented can be applied to synthesize the manipulator for any number of positions. A numerical example for the synthesis with 10 positions is presented.