Liveness supervision of AMS with complex processes using Petri nets

In the context of automated manufacturing systems (AMS), Petri nets are widely adopted to solve the modeling, analysis, and control problems. So far, nearly all known approaches to liveness-enforcing supervisory control study AMS with either flexible routes or assembly operations, whereas little work investigates them with both. In this paper, we propose a novel class of systems, which can well deal with both features so as to facilitate the investigation of more complex systems. Using structural analysis, we show that liveness of such systems can be attributed to the absence of undermarked siphons, which is realizable by synthesizing a proper supervisory controller.