A Hybrid Petri Nets Approach for Railway Systems

Railway systems are usually hybrid, huge and complex, composed by both discrete events and continuous properties. Therefore, we need a compact and effective method to model and analyze them. In this work we propose a hybrid Petri nets approach. We first provide the method of modelling the basic elements such as segments, switches; then, a bottom-up procedure is proposed to build a complete railway system. Enumerative analysis is performed and algorithms for constructing the reachability graph are provided. Different from previous works that mostly only consider discrete states of the model, we also emphasize continuous parameters, such as speeds, times and positions. Segment agents and connection agents are introduced to manage the state evolvement of the system, and ensure that the railway network is in a safe condition.