First, the branched-chain of parallel mechanism was Classified according to reciprocal screw theory. Then, the introduction of variable topology mechanism theory, with the characteristics of parallel mechanisms themselves, the definition and basic variable topology means of variable topology parallel mechanism were given. With evolutionary theory, the method to design lower-mobility parallel mechanisms of non-asymmetric was proposed based on variable topology mechanism theory .Taking 3-RPS as ideal mechanism and topology synthesis was carried out, besides 2-RPS mechanism were analyzed. The introduction of variable topology mechanism theory provided a theoretical basis and innovative approaches for the synthesis configuration of Lower-mobility parallel mechanisms of non-asymmetric.

A new type of variable topology parallel tire building drum mechanism was presented in this paper and the solid model of the mechanism was established. The elastic dynamics model has been established by the condition of displacement and power which the rigid connected with elastic body. The model of variable topology parallel mechanism was imported into the ADAMS and analyzed the elastic dynamic simulation of the mechanism.