A key issue in automated seaport container terminals is the assignment of transportation orders to automated guided vehicles (AGVs). For AGV dispatching two basic types of strategies can be applied, which differ by the length of the look-ahead period and the rescheduling strategy. The on-line dispatching strategy uses myopic dispatching rules, which have been adopted from flexible manufacturing systems.
This strategy schedules only one operation at a time without ever changing an existing schedule. As an alternative, a pattern-based off-line heuristic developed by the authors can be applied. This heuristic creates predictive schedulescomprising a sequence of pick-up and drop-off operations for each vehicle getting available during a given look -ahead horizon. To evaluate the performance of the dispatching strategies a comprehensive simulation study is performed. The scenarios investigated reflect realistic terminal environments and consider stochastic variations in the timing and processing of loading and unloading operations of containers.