Research On Synthesis Theory And Method Of Multi-bar Linkages Based On Solution Region

The result of mechanism synthesis determines the performance of the machine, and the ability to synthesize the better performance of the machine is the embodiment of the competitive ability of mechanical products. Efficient and practical mechanism synthesis method is critical to the economy and efficiency of mechanical products, and it is the primary link of product development and market competition. Using the relevant theoretical research achievements for reference, positions synthesis theory and method of planar multi-bar linkages and spatial 5-SS linkage are presented based on the solution region synthesis method of planar four-bar linkages. The main contents of the research are as follows:(1) The synthesis method of RR linksIn this paper, the synthesis method of RR links is presented, according to the specified four positions of two or one rigid body. Firstly, the binary cubic synthesis equation is derived based on the length constraint of the link, and the curve expressed by the equation is called the solution curve. Then, the discrete generation method and sequential generation method of the solution curve are given. The points on the solution curve can be solved in discrete by using the discrete generation method of the solution curve. The points on the solution curve can be solved in order by using sequential generation method of the solution curve.(2) Four positions synthesis method of six-bar linkagesThe solution region synthesis theory and method of four-bar linages are expaned and applied to solve the problem of four positions synthesis of six-bar linkages. Adding two RR links to the 3R open chain, the 1-DOF six-bar linkage can be obtained. Seven ways of adding two RR links are given, and they are divided into two types, based on the depency between the two added RR links.The methods of building the local and global solution region are presented, based on the discrete generation method and sequential generation method of the solution curve. The synthesized linkages are expressed by the solution region.Based on the position analysis and Jacobian analysis, the identification method of six-bar linkages's defect is presented. If the signs of Jacobian values for specified positions are not the same, the linkage is defect. Given the input angle, there is no solution by position analysis. According to the position analysis and the continuous motion conditions of linkage, the obtained assembly configuration and the specified assembly configuration is different, the linkage also has defects.(3) Four positions synthesis method of eight-bar linkagesAdding three RR links to the 4R open chain, the 1-DOF eight-bar linkage can be obtained. There are 153 ways of adding three RR links, and they are divided into five types. According to the process of synthesis and adding the RR link for eight-bar linkage synthesis, the methods of building the solution regions are presented. Based on the linear actuator, position analysis and Jacobin analysis of eight-bar linkages, the identification method of eight-bar linkages's defect is proposed. Using this method, defect linkages are eliminated from the solution region.(4) Six positions synthesis method of spatial 5-SS linkagesThe method of six positions synthesis of 5-SS linkage is proposed. The synthesis of SS link is the base of 5-SS synthesis. The synthesis equation of 5-SS synthesis is derived and solved. The method of building the solution region for 5-SS synthesis is based on the solution region synthesis theory of planar linkages synthesis combined with the process of 5-SS linkage synthesis. According to the position analysis and Jacobin analysis of the 5-SS linkage, the identification method of 5-SS linkage's defect is presented. The defective linkages are eliminated from the solution region.(5) Software development for mechanism synthesisThe software systems of planar linkages synthesis and 5-SS linkage synthesis are designed and developed by employing a mixed programming method of Visual C++, Matlab and OpenGL, based on the proposed synthesis theory and method. Software systems of linkages synthesis have friendly man-machine interface, and can carry on the linkages synthesis and movement simulation, and the data is stored in the process of synthesis and simulation. Software systems of linkages synthesis can be used to complete the illustrations, which show the validity and feasibility of the proposed linkages synthesis theory and method of this paper.