Abstract: A new type of serial-parallel manipulator with 6 degrees of freedom(DOF) is suggested based on traditional serial manipulator and parallel manipulator. Three dimensional translation and rotation of output shaft are obtained through lineal driving. One first level serial component and one first level parallel component are acquired by using decomposition and synthesis after the first time decomposition. Four second level serial components and two second level parallel components are obtained after the second time decomposition based on the first level serial component and parallel component respectively. Each group of second level components is presented by equivlant mechanism. Each level of components is integrated reversely, thus the equivlant mechanism of the primary mechanism is obtained. Formula and ability of working space are used to obtain the DOF of this mechanism, also intuitionistic solid figure. Analytic geometry is used to obtain the regular cuboid of the reachable working space shape of mechanism, the volume of the reachable working space rest with the limit of translation of couplers. The rotational angle limit of output shaft at given configuration is analyzed through the method of drawing. Limit length of the vertical elongable poles is the primary influential factor.

Key words: Decomposition, Degree of freedom, Serial-parallel manipulator, Synthesis, Working space