Planning and design of automatic assembly systems using artificial intelligence

Abstract

In most manufacturing industries, assembly systems have been widely used for high volume production. Especially, automatic assembly systems using industrial robots and assembly equipment have been increasingly used owing to the progress of automation technology. Such assembly systems need to be economically designed along with meeting demand of products for achieving reduced cost and increased productivity. For such purposes, the study deals with practical planning and design issues for automatic assembly systems by including sequence generation, line balancing and tool change strategy. The thesis firstly presents methods of optimization of automatic assembly sequences for minimizing assembly cost. An assembly sequence is considered to be optimal when it meets a number of conditions: it must satisfy assembly constraints and minimize assembly cost. To generate such sequences, three methods are proposed: neural- network-based computational method, simulated annealing method and genetic algorithm. Through case studies for industrial products, the effectiveness of the methods are demonstrated, and then the results are compared with each other for analyzing the performances. In addition, assembly systems need to be adequately balanced to meet demand of products. This objective can be achieved by minimizing both the number of workstations and the deviation of station times among workstations. To this end, a simulated annealing method of solving dual criteria single-model and deterministic (SMD) assembly line balancing (ALB) problems is proposed. However, if assembly sequences are generated without considering line balancing, the sequences found may not guarantee the minimum number of workstations. In this case, additional cost is incurred to accommodate the increased number of workstations. Therefore, the line balancing should be included in generating assembly sequences Another factor that should be considered in designing automatic assembly systems is assembly ...