The Flexible Assembly Line Design For Valves Based On The Improved Particle Swarm Optimization Algorithm

The research of the thesis comes from the crosswise projects “The structure design of the αβ butterfly valves and the flexible assembly line design for valves”. The main research contents of the thesis is the flexible assembly line design for valves, the issue consists of two parts: the balance of the flexible valve assembly line and the production sequence problem of different valves.Firstly, the mathematical model about the flexible valve assembly line is established. Combined with the results of field investigation, the flexible valves assembly line is designed in the general, and on the basis of the design, the technical parameter of the flexible valve assembly line is calculated, meanwhile, the structure analysis of the valves and the analysis of assembling procedure is completed.Aiming at the poor discreteness and low search capability in the calculating process of the particle swarm optimization algorithm(PSO), an adaptive discrete algorithm is proposed, and in the same time, based on the simulated annealing algorithm and tabu search algorithm, a series of algorithms aiming at improving the search capability are proposed; the algorithm was proved the effectiveness by different examples.The variances between different kinds of valves in the assembly process making the flexible assembly line design for valves much harder, and an flexible valves assembly line balancing model aiming at optimizing the number of workstations, load fluctuations factor and coupling degree between different valves assembly line is built, based on the analysis and merging of different valves assembling procedure; during the solutions, a particle swarm initialization algorithm based on the heuristic algorithm and random algorithm is designed, and a fitness function is built through the normalization method and multi-objective optimization method; on the basis of the result, buffers are designed through simulation analysis of EM-Plant.Aiming at the inventory and time cost variances because of different production sequence, a production sequence model aiming at optimizing the inventory cost, overhead time and preparation time cost based on the analysis of the flexible assembly line design for valves is built; by building the fitness function through the normalization method and multi-objective optimization method, the production sequence problem is solved, and the sequence designed in this thesis is proved the superiority by comparing with the result of analyzing the overhead time only.Through the above research, a flexible valves assembly line which has minimum workstations number, small load fluctuations and high coupling performance is completed; an assembly work schedule in one producing batch was made, and the enterprise cost is lowest in this way.