Universität Stuttgart
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Item Open Access Simulation based hybrid model for a partially automatic dispatching of railway operation(2010) Cui, Yong; Martin, Ullrich (Prof. Dr.-Ing.)The efficiency and service quality in railway operation can be improved with the support of a partially-automatic dispatching system. Three types of automatic dispatching system model are prevailing: simulative, analytical, and heuristic. However, none of them is able to reconcile the different preferences between system performance and the quality of dispatching solutions individually. A hybrid model is therefore designed in this dissertation. In the hybrid model, the synchronous simulation is utilized as a basis in order to generate a basic dispatching solution. This dissertation focuses on the components and the workflow of a synchronous simulation and addresses the deadlock problem during a synchronous simulation. Deadlock avoidance can be achieved by the Banker's algorithm and the associated improvements, which are designed to prevent trains from unnecessarily stopping and to improve system performance. The implementation shows that the synchronous simulation can reschedule train movements reliably, and the Banker's algorithm can deal with deadlock problems even for very complex train movements (e.g. shunting movements). In a simulative dispatching mode, the calculated train priority parameters are utilized in requesting infrastructure resources, allocating infrastructure resources, or both. After a basic dispatching solution has been generated, further optimization can be carried out on a macroscopic level, and then be elaborated on a microscopic level. Several different optimization techniques, including Tabu search and Linear Pro-gramming, can be utilized in such a multi-level dispatching and optimization frame-work. Finally, an optimized dispatching solution will be developed with consideration to the balance of system performance and dispatching solution quality using a simulation-based hybrid model. In this dissertation, the framework of a hybrid model for a partially-automatic dis-patching of railway operation is proposed. A synchronous simulation model is implemented in the work of the dissertation as the basis, from which further implementation can be designed and be developed continuously.