Abstract: Hybrid robot mechanisms has both better performances and advantages which combines the better stiffness and precise position that parallel mechanism owns and the bigger workspace and better control decoupling that series mechanisms owns. The key of design hybrid robot is the number of DOFs in series or in parallel, the order distribution of DOFs, the combination method of DOFs based on position and orientation characteristic (POC) set of manipulator, and the module structure and performance evaluation of novel parallel mechanisms with less DOF. The design method for hybrid robot based on freedom distribution and POC set is proposed, including the definition, symbol denotation method and the advantage and disadvantage analysis of both hybrid robot with single-point operation and hybrid robot with mult-point collaborative operation. Accordingly, all the possible structure combinations, design principles and design procedure of hybrid robots with 3～5 DOFs are given. A lot of novel topological structures of hybrid robot were designed. Meanwhile, both 5-axis hybrid robots with single airbrush and with mult-airbrush for spray painting are developed respectively according to the design method. Furthermore, the performance for the two spray robots with different structures is compared. The research provides a general method for hybrid robot mechanism design and provides mechanism design theory basis for development of complex advanced equipment.

Key words: Hybrid mechanism, Hybrid robot, Parallel mechanism, Type design