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Study Of The Optimum Synthesis Method Of The Planar Six-bar Dwell Mechanism

Posted on:2007-06-21Degree:MasterType:Thesis
Country:ChinaCandidate:Y Y WangFull Text:PDF
GTID:2132360185981005Subject:Mechanical design and theory
Abstract/Summary:PDF Full Text Request
This paper, from the origin of engineering practice, conducted a thorough research on the function synthesis of planar six-bar dwell mechanism and discussed its theory and methods in details by using the theoretical achievements of many fields such as plane link motion geometry, optimum method, computer value computation and graphical display technology.One method that Stephenson-III planar six-bar mechanism redisplays itself to given intermittent transmission function was introduced on the basis of planar link mechanism optimized synthesis including adaptive fitting method by the simple curves. The united and optimized mathematical model and error-evaluated method was also set up by summing up the problem that three types of six-bar dwell mechanism close to function synthesis as Specifically Link-ⅡGroup—RRR, RRPorRPR with the pre-synthesized four-bar mechanism.The optimized model of function synthesis of planar six-bar dwell mechanism in this paper is divided into two relatively independent sub-questions. One is a kind of special constrained non-differential optimal problem of max-mini optimal aim while getting the most approximate circle or line from the points'orbit on link bar. It can be resolved by the method of Saddle-point Programming and maximum entropy, it can be transformed as a differential optimal one with single objective. The other is to search the optimization of the framework points within mechanism-designated space. Its model is nonlinear, multiple-constraint and non-differential problem. It can be resolved by differential evolution algorithm.In this paper, the initial value was structured with the random search characters of differential evolution algorithm and every parameter can be optimized with the character that differential evolution algorithm can converge overall optimization on any initial value. As for error-evaluation, this paper, by using the Weighting Theory, made the errors between the non-intermittent parts as little as possible under the conditions that the required planar six-bar mechanism could satisfy the precision requirements between intermittent parts.According to the comprehensive thought of the six-bar dwell mechanism optimization, this paper did the calculation by examples and verified the feasibility and efficacy of this method.
Keywords/Search Tags:planar six-bar dwell mechanism, approximate function synthesis, saddle point programming, and differential evolution algorithm
PDF Full Text Request
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