The design methodology for fewer input-more output parallel mechanisms

Based on the industrial application background, the concept and methodology for fewer input-more output parallel mechanisms, Fi-Mo mechanisms, are proposed. The most important characteristic of Fi-Mo mechanisms is that parasitic motions of these mechanisms are utilized fully which are generally viewed as harmful motions and eliminated. The research background, definition and characteristics of Fi-Mo mechanisms are introduced. Then, design methodology for Fi-Mo mechanisms is established, which includes 1) a mathematical model which correlates the number of actuated input (W), degrees of freedom (DOF) and numbers of output motion (position and orientation) (N_out) is deduced; 2) the design principles and flow chart for designing Fi-Mo mechanisms are proposed; 3) all (1-5) DOF Fi-Mo parallel mechanisms of sixty-nine types are put forward. Meanwhile, topological structure theory for parallel mechanisms based on position and orientation characteristics (POC) set and ordered single-open-chain (SOC)units used to analyze topological characters of Fi-Mo mechanisms is introduced. Furthermore, two examples of 1-DOF 1T2R, 1-DOF 3R output Fi-Mo mechanisms and their prototypes, novel parallel vibrating screen and parallel foot massager, have been designed to illustrate the design methodology.