Synthesis, Analysis And Simulation Of Adjustable Mechanisms

The adjustable mechanisms is a kind of innovative mechanisms which comes forth with incessant development of mechanics. It is a product of combining traditional mechanisms with modern application technology, and has very vast potential applications. The advantages of adjustable mechanisms are that they have flexibility and can carry out multiple alternation tasks effectively as compared with traditional mechanisms. Their flexibility is between traditional mechanisms and robots. Compared with robots, adjustable mechanisms are more reliable, more accurate, easier to manipulate and maintain, and more economical. In this thesis, synthesis of adjustable mechanisms, dynamic models of planar close-chain mechanism and parallel mechanism, and a new type parallel machine tool based on virtual prototype are studied.The method of optimization synthesis of adjustable mechanisms for multiple alternation tasks based on evolutionary computation is presented, which can effectively solve the problem of easily running into local optimization solution by using traditional optimization method. In order to improve the optimization capability effectively, the algorithm of evolutionary computation is improved, and a method that can adaptively adjust mutation rate and mutation value according to fitness of individual is proposed. Take examples for rigid-body guidance synthesis of planar four-bar mechanism and function synthesis of planar six-bar mechanism to illustrate the method.Analytical dynamic model of planar close-chain mechanism, in which lengths and the inertia parameters of links can be changed, is established based on sub models of links, and a parallel algorithm is also proposed. The mechanism is disassembled to individual links and the dynamic sub models are established...