The Reserch On Dynamic And Parallel Global Optimization Method Of Process Scheme

Process optimization is important means of reasonable arrangements for the production process, optimizing and conserving manufacturing resources, shorting production cycles, reducing production costs, improving product quality, and promoting technological progress. Process optimization has become a recognized problem in CAPP and even digital design and manufacture. A dynamic, parallel global process optimization method is designed as a useful exploration and practice to solve process optimization problem.Subject background, source and purpose is introduced. The process optimization methods are summarized. The main tasks are explained.The substance of process constraint is summarized. According to the own characteristics and application scope of constraint relations priorities of the machining methods, constraints of machining resources and constraints of cutting parameters, three different treatment methods are designed. Based on analysis of the facts that machining scheme influence the processing line and process parameters, the machining scheme optimization principles -- the greatest probability of selection, the least processing method and the shortest processing chain is determined. Mathematical optimization model is established.The actual coding method based on multi-branch structure is adopted on the basis of global process optimization characteristics to express process scheme. Random depth-first search algorithm is adopted to achieve population program initialization. Based on analysis of machining methods priority relations, process route mathematical model and fitness function of process route optimization are established to use optimal constrans as optimization goal. The special process route optimization operator is constructed in order to ensure priority of mechining methods, and meet the processing sequence integrity constrans. Considering the state of workshop and resources machining capabilities, The optimization objective function of processing resources is established. The corresponding machining resources choice operator, crossover operator and mutation operator is constructed According to variable continuity features of machining parameters, the corresponding crossover and mutation operator is designed.The process scheme evaluation system is established analyzing a variety of factors, and through qualitative analysis and quantitative analysis, process global optimization objective functions-- the production efficiency, production costs, production profits and machining quality are constructed. The multi-objective genetic algorithm is adopted to find directly process scheme multi-objective optimization Pareto frontier, and the method of parallel dealing with a number of objectives to realize global process optimization. According to a "decomposition -- simplification -- Integrated -- Integrated again" thinking and strategy, on_demand, decision-making process system is established, and the on-demand multi-objective decision-making matrix is given.The architecture of the prototype system that realizes the research contents of the dissertation are given, and the prototype system is applied to a practical process planning case. Therefore, the feasibility and the effectiveness of research results are validated. In the end of the dissertation, conclusions have been drawn and the future directions in the field are given.