Hierarchical deadlock control of automated manufacturing systems with complex structures

Deadlock-free operation is a critical objective in automated manufacturing systems (AMSs) to ensure smooth and efficient production processes. While many studies have aimed to obtain computationally tractable and efficient control policies for deadlock resolution, a significant limitation is that they often restrict their models to structurally simple systems. Taking Petri nets (PNs) as a modeling and analysis tool, our focus in this paper is on addressing deadlock resolution for forward-conflict free nets through an on-line distributed control method. One notable advantage of the proposed approach is its ability to enable real-time deadlock avoidance through local observation, control, and execution of processes, without relying on external or extra information about the system. This means that our method can be applied to larger and more intricate manufacturing systems without substantial modifications or loss of efficiency.