Performance evaluation of a flexible manufacturing system with in-process buffers

Abstract

This thesis is concerned with the performance evaluation of a flexible manufacturing system with in-process buffers. In-process buffers are composed of limited input and output buffers. The first part of this thesis is devoted to investigating a queueing network model for the performance evaluation of a flexible manufacturing system with limited input and output buffers, where machine blocking is allowed and two automated guided vehicles (AGVs) are used for handling input and output materials. An iterative solution algorithm is exploited to approximate system performance measures by using the theory of reversibility. A variety of numerical problems are solved to show the effectiveness of the algorithm in comparison with simulation approach. The second part is concerned with the same model except that a single automated guided vehicle (AGV) is used for handling input and output materials. An approximation algorithm to derive the system performance measures is developed by characterizing the reversibility of the system rather than by solving the associated conventional balance equations. The algorithm is illustrated with numerical examples. The third part is concerned with design aspects of a flexible manufacturing system composed of several parallel workstations each with both limited input and output buffers. The optimal design decision is made on "the number of AGVs", "allocation of workload (routing probability)" and "allocation of buffer space" with the given performance evaluation model. Some properties of the system throughput measure are derived to characterize the optimal system configuration. The last part is concerned with an application to an open queueing network of merge configuration with blocking allowed. An efficient algorithm to derive the marginal queue length distribution is exploited by using the theory of reversibility rather than by solving the associated conventional balance equations. The algorithm is evaluated for its efficiency in compa...