Type Synthesis Of Generalized Deployable Mechanisms

With the development of mechanism, more and more new mechanisms appear. Many new appearing mechanisms contain new components and new kinematic pairs, which are different from traditional mechanisms. The theory of traditional mechanism is not suited for the new mechanism, so the theory system of generalized mechanism is extended. The paper researches the deployable mechanism from several aspects based on the foundation, the corresponding achievements are obtained.Firstly, the history of the traditional developable mechanism is reviewed, the generalized development are proposed. Combining the knowledge of graph theory, topology expression and matrix expression are put forward. The difference between traditional mechanism and generalized mechanism is elaborated. The significance of generalized development mechanisms appearing is researched. The types of generalized development mechanism are summarized based on the topology expression and matrix expression. At the last, some practical applied examples for generalized development mechanisms in aviation and aerospace field are shown.Secondly, the finite group theory is introduced to the type synthesis of generalized deployable unit based on the topology expression and matrix expression of generalized. A briefness and effective type synthesis method is presented based on the basis of group theory. The mechanism is divided into components and kinematic pairs, the two parts are expressed with group; the permutation group is used to obtain the all permutation forms of generalized kinematic pairs and generalized components. The type matrixes of generalized deployable unit are obtained through combing two groups, and the topological types of generalized deployable units are gained. The rules of combing two groups are researched. The Incidence Degree Code is adopted to detect the isomorphism of the obtained type matrixes, and the detection of isomorphism ensures the uniqueness of types. The all types of generalized deployable units of four bars and six bars are obtained through the method.Lastly, the networks method of generalized deployable units is discussed, the modular design is adopted for generalized deployable mechanism. Graph theory and extenics basic-element theory are proposed, the matter-element, affair-element and relationships-element are corresponded to specific physics substance. Based on the foundation of summarizing eight assembled types of generalized deployable units, the Networks rules of generalized deployable units are raised. The common link is the common part of several generalized deployable mechanism, those common part are generalized component and generalized kinematic. The common links are defined to mapping. With the theory of extension knowledge space, the element of extension field is transformed to different generalized deployable mechanism with different mapping, the different generalized deployable mechanisms make up of extension knowledge space. The Networks rules are applied to a four-bar and a six-bar generalized deployable mechanism for type synthesis for obtaining Networks types of the generalized deployable mechanism.