The research of kinematic performances of 3-UPU-UPU parallel mechanism for automobile assembly line

According to the requirement of body-in-white (BIW) positioning and conveying between different processing stations in the flexible assembly line, a four support positioning body-in-white flexible conveyor system based on the 3-UPU-UPU parallel mechanism was proposed. The inverse equation of the parallel mechanism and velocity Jacobin matrix was solved on the basis of the kinematics of 3-UPU-UPU parallel mechanism. Simultaneously, feasible points was derived. Then the model of the global dexterity and global maximum bearing capacity was built. The workspace feasible points, global dexterity as well as the global maximum bearing capacity were selected as the performance indices. The mechanism was optimized by using the weighted sum method. Taking the optimized size parameters of the mechanism for example, this paper analysed the workspace, dexterity and bearing capacity of the mechanism. The results prove that the 3-UPU-UPU parallel mechanism has good kinematic performances, it can be used as the positioning support body of different models body-in-white to complete body-in-white positioning and conveying between different processing stations, and has important research significance and application promotion value.