Efficient Supervisory Synthesis to Large-Scale Discrete Event Systems Modeled as Extended Finite Automata
Zhennan Fei, Sajed Miremadi, Knut Åkesson, Bengt Lennartson · Chalmers Research (Chalmers University of Technology) · 2012
The state-space explosion problem, resulting from the reachability computation of the synthesis task, is one of main obstacles preventing the supervisory control theory (SCT) from having a major industrial breakthrough. To alleviate this problem, a well-known strategy is to utilize binary decision diagrams (BDDs) to represent system transition relations and compute supervisors symbolically. Based on this principle, we present in this paper an efficient reachability approach to large-scale discrete event systems modeled as finite automata with variables. By making use of the disjunctive partitioning technique, the proposed approach partitions the transition relation of a considered system into a set of partial transition relations according to included events. Then those partial transition relations are selected systematically to perform the reachability computation. Consequently, more iterations might be required to compute the fixed point, but the inter- mediate BDDs are smaller. As a supplement to prior framework, the approach has been implemented in the supervisory control tool Supremica and the efficiency is demonstrated on a set of industrially relevant benchmark problems.