An Optimal Design Approach for Fault-Tolerant Petri Net Controllers Using Arc Weights Minimization

This paper proposes an approach for the optimal design of fault-tolerant Petri net controllers using arc weights minimization. Given a system controller that is modeled as a Petri net, a fault-tolerant Petri net controller is obtained by embedding the given Petri net controller into a larger (redundant) Petri net controller that retains the properties of the original controller and allows the detection and identification of faults that may occur in the controller places. An algorithm is developed to systematically design this fault-tolerant Petri net controller in an optimal sense. The optimality is in terms of minimizing the sum of the entries in the input and output incident matrices of the fault-tolerant controller. Examples of the optimal design of fault-tolerant Petri net controllers for a manufacturing system are also provided to illustrate our approach.