Six Intermittent Plane Approximation Functions Theory And Methods Of Research

A new approach of approximate function synthesis for planar six-bar dwell mechanism is presented in the dissertation, based on the theory of Self-Adapted Approximation of Simple Curves, which transforms the synthesis of planar six-bar mechanism to the synthesis of special groups of link II, such as RRR, RPR, as well as RRP, reduces the variables to two or three or four ,by selecting all dimensions of the four-bar mechanism in advance. And then, unified model of function synthesis of planar six-bar dwell mechanism is set up.The model of function synthesis of planar six-bar dwell mechanism in the dissertation is decomposed into two relatively independent sub-questions. The first one is to evaluate the characteristic of points on coupler curve, whose mathematics model is a kind of special non-differential max-mini optimal problem with inequality constraints. By the method of Saddle-point Programming and maximum entropy, the problem can be transformed as a differential optimal problem with single objective. The second one is to search approximately characteristic points on fixed rigid body within design space, whose mathematic model is nonlinear and non-differential problem with multiple constraints. By genetic algorithm followed by BFGS method, the problem can be resolved.For a general optimal approach, the results depend on the initial point and the choice of initial point is difficult. In this dissertation, a new approach is proposed by genetic algorithm, so that a series of good initial points can be produced automatically, and with BFGS method the search for global minimum is accessible.According to the approach, the software, which realizes the approximate function synthesis for planar six-bar dwell mechanism, is programmed, and results of different synthesis examples are given to illustrate the effectiveness of the approach.