Online control reconfiguration for a faulty manufacturing process

This paper proposes an online reconfiguration method for discrete event systems described by nondeterministic Input/Ouput automata. The method modifies the control law to circumvent the effects of sensor and internal system failures. It is based on a necessary and sufficient reconfigurability condition published recently. The main result is an online reconfiguration procedure that is based on backward and forward recovery strategies for discrete event systems subject to faults. After a failure has occurred, checkpoint states and control laws are iteratively computed until a state is found from which the process can be resumed. The applicability of the approach is demonstrated on a “pick & place system”.