Abstract: Tandem robots of closed chains are composed of several planar four-bar linkages and dimensional bar linkages. Defining the shortest open chain from the base to the operation terminal as a major chain, the kinematic analysis problem is turned to the sub-problems of the kinematic analysis of an open chain and several single closed chains. The kinematic analysis of the major chain can be done by the product exponentials formula. The positions and velocities of the major chain can be got from the kinematic analysis of the closed chains. The kinematic analysis of the planar four-bar linkage and dimensional six-bar linkage can be done by building up the structural equations. Finally, the results of the kinematic analysis of the major chain and that of the single closed chains are synthesized; And then the kinematic analysis of the whole tandem robot of closed chains is finished.

Key words: Screw theory Kinematic analysis, Tandem robot of closed chains