Operational-safety supervisory control: an approach to supervisor activation

Operational safety concept advocates the design and synthesis of fault-tolerant supervisory control policies able to deal with conflict. A recovery procedure technique based on supervisor activation is introduced in this work to contribute to fault-tolerance in terms of operational safety. The proposed formalization introduces the concept of activation at a high level, the switching function of a supervisor and a mechanism of forcing states. After a brief presentation of the usual recovery techniques in the domain of automated manufacturing systems (AMS), the extension of the automata theory by recovery procedures which activate and deactivate supervisors is described. The formal description is presented, and a simple example is given