Fuzzy modeling and harmony search optimization for machining system with general repair, standby support and vacation

摘要

The queueing analysis of a multi-component machine repair system comprising of operating as well as standby machines and a skilled repairman has been investigated. The server may go for the vacation of random length when there are no failed machines queueing up for the repair job. By taking the remaining repair time as a supplementary variable, the steady state queue size distribution of the number of failed machines in the system is established. Laplace–Stieltjes transform, recursive and supplementary variable approaches are used to derive various system indices such as mean queue length, machine availability, system availability, and operative utilization, etc. To deal with a realistic scenario, the machine repair model is transformed from crisp to fuzzy environment by considering the system parameters corresponding to failure, repair and vacation rates as fuzzy numbers. The numerical illustration and practical application of a flexible manufacturing system for specific repair distributions are presented to visualize the effects of the system parameters on various performance indices. To explore the practical utility of the investigated model, the cost function is framed and cost optimization problem has been analyzed by using Harmony search approach.