Type Synthesis Of Parallel Mechanisms Based On Modificatory Formula For DOF

The parallel mechanism is a kind of robot structure. It has the characteristics of high accuracy, rigidity, speed, and large load carrying capability. Researching the problem of type synthesis of parallel mechanisms is propitious to obtaining new parallel robotic mechanisms in practical application, and lays the foundation for the design and manufacture practical parallel robot. On the other hand, it helps to work up a common technique of type synthesis and has a higher value theoretically.This paper focuses on the synthesis of the parallel mechanisms based on modificatory Grubler's formula and aims to establish a universal and effective theory for parallel mechanisms with overconstrained. The main contributions are as follows:A systematic linkage technique and a topology matrix-graph approach are put forward for type synthesis of parallel mechanisms with consstrained. By using the systematic linkage technique, numerous acceptable associated linkages of parallel mechanism can be derived. From the acceptable associated linkage and by using the approach of topology matrix-graph, topology embryonic graphs and topology graphs of various parallel mechanisms can be derived ,as the foundation of studying the subject of type synthesis further.Based on the geometric constraints and dimension driven techniques, a novel computer aided geometric approach is put forward for designing the computer simulation mechanisms of parallel manipulators. Some spacial parallel simulation mechanisms with overconstrained are configurate. When the driving dimensions of driving limbs are modified, the configuration of the simulation mechanisms are varied correspondingly. The correctness of the DOF and movability of parallel mechanisms synthesized in this paper can be validated. The research work of this dissertation establishes theoretical basis for the further research of type synthesis of parallel mechanisms.