State based control of timed discrete event systems using binary decision diagrams

This work discusses a new synthesis approach to the supervisory control of timed discrete event systems (TDES), that is more efficient than the existing approaches. With this method, many practical systems can be synthesized on a personal computer. The method exploits binary decision diagrams (BDDs), adapted to the specific structure of TDES. It is shown that the number of nodes in the BDD representing a TDES can be a better measure of the complexity of the TDES than the number of states and transitions. Structural information based on the ‘timers’ for a given TDES together with the reduction properties of BDDs contributes to efficient performance. The success of our approach is illustrated with large versions of an existing example taken from the literature.