Topology Array Synthesis Theory And Computerization Research Of Parallel Mechanism

Extensive use of parallel mechanism promotes the continuous development of itsinnovative research. Mechanism topology graph type synthesis as the primary means ofmechanical design has become a very important research topic and direction in recentyears. Synthesis of parallel mechanisms is researched in this paper using an array as themain means. Parallel mechanisms synthesis is divided into two steps: synthesis ofcontracted graphs and synthesis of topology graphs based on acceptable associatedlinkages. The solution is put forward for key link contracted graphs and topology graphsisomorphism identification problems. The following questions are mainly researched inthis paper:Synthesis of contracted graphs is achieved. One of key issues of isomorphismidentification of contracted graphs is solved. Contracted graph has unique feature becausethere aren't binary links in limbs. Aiming at this feature, contracted graphs are identified ifthey are isomorphic by path array according to the theory about adjacency matrix in graphtheory. Automatic creation of contracted graphs is achieved. Based on acceptableassociated linkages, contracted graph adjacency matrices creating algorithm is proposedand its complexity is acceptable. All acceptable adjacency matrices are derived by thisalgorithm. Isomorphic contracted graphs are deleted and different and acceptable ones areremained after identifying isomorphism. Contracted graphs are synthesized based on someassociated linkages.Synthesis of topology graphs is achieved based on synthesized contracted graphs.The solution is proposed for key links of isomorphism identification of topology graphs.Topology graph are described by character array. Character array is used as the criterion oftopology graphs isomorphism identification. Automatic creation of topology graphs isachieved by character array permutating. The algorithm that can create all acceptablecharacter arrays is provided. Isomorphic character arrays are deleted and different ones areremained after identifying isomorphism. Corresponding topology graphs are drawn.Examples are given to illustrate topology graphs synthesis procedure. Topology graphs aresynthesized for some plane 3DOF and 4DOF parallel mechanism. Limbs of topology graphs can be synthesized by kinematic pairs equivalentsubstituting for synthesized topology graphs. Basic limbs and general limbs for differentDOF can be derived by changing different kinematic pairs combination. Different limbsare made up different structure parallel mechanisms. Limbs of some spatial 3-DOFparallel mechanism without redundant constraint are synthesized.Some synthesized topology graphs are simulated. Some simulative mechanisms areconstructed by the use of CAD variable geometric techniques. Constructing procedure isintroduced simply and DOF of simulative mechanisms is verified by DOF formula. fourplanar 4DOF redundant closed mechanisms are synthesized.Isomorphism identification of kinematic chain topology graphs is a world trouble.Relevant research to this problem is conducted. Firstly, a necessary condition of kinematicchain topology graph isomorphism identification by spanning tree is put forwardcreatively. Non-isomorphism of kinematic chain topology graphs are identified byspanning tree. This method is proposed because solving process of this necessarycondition is very simple and usage is easy to grasp. Accuracy of next identification ofisomorphic kinematic chains can be is greatly increased. Secondly, isomorphismidentification of contracted graphs and topology graphs is sumed up. They are extendedout universal significance in isomorphism identification of kinematic chains. A method ofisomorphism identification of kinematic chain topology graphs based on contracted graphis proposed.