A review of design and control of automated guided vehicle systems <s> Conflict resolution <s> Abstract The problem of organizing and controlling the material handling activity in an AGV-based material handling system for a flexible manufacturing system involves several decisions such as the number of vehicles required for the system, the layout of the tracks, the dispatching rules for the vehicles and the provision of control zones and buffers. This paper demonstrates the use of a two-stage approach for solving the problem. The required number of vehicles is estimated using an analytical model in the first stage. In the next stage, the effects of AGV failures and AGV dispatching rules on the system performance are observed through simulation studies based on which the AGV dispatching rule can be chosen. <s> BIB001 </s> A review of design and control of automated guided vehicle systems <s> Conflict resolution <s> We consider a manufacturing job shop with automated guided vehicles. Such a system is characterized by several complex features such as the random pattern of material flows between machines, the limited capacity of machine buffers, shop deadlock phenomena, floating bottlenecks, etc. We will describe a heuristic procedure for the control of materials flows and automated guided vehicles in such a system. The procedure is based on the idea of workload balancing; it tries to balance the workload among machines as well as the workload between the machines and the transporters. A deadlock prevention algorithm is embedded in the procedure. We then present the results of simulation experiments to evaluate the performance of the proposed procedure. <s> BIB002
Balancing the system workload When machines in a manufacturing system or the P/D locations in a distribution center have only little space for load buffering, the system might be blocked by buffers overflowing. Possible reasons include insufficient buffering capacity or an inappropriate scheduling (dispatching) system. To cope with the first problem, a central buffer may be introduced to solve the temporary blocking problem. BIB002 show that the central buffer has an important influence on the system performance. The second problem can be solved by applying workload-related dispatching rules  BIB001 BIB002 .