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7
Conclusions
In this paper, we improved and extended our previous work, the guard generation pro-
cedure to make it applicable for industrially interesting applications. More specifically,
the content of the paper can be summarized as follows:
-
Introduce the partitioning techniques to split the BDD representation of
δ
SpP
into
a set of smaller but structural components.
-
To alleviate the problem that the intermediate number of BDD nodes might still
be huge during the reachability exploration, we introduce the workset algorithm
together with a set of simple heuristics to search the state-space in a structured and
efficient way.
-
The guard generation procedure is tailored to make use of the partitioned transition
functions and the synthesized supervisor to compute the basic state sets for an event.
-
The presented approach is applied to a set of benchmark examples to be evaluated.
It is concluded that the disjunctive partitioning, with appropriate heuristics, is suitable
for solving large modular supervisory control problems. There are several directions
towards which we could extend our approach. For instance, additional heuristics could
be applied to the workset algorithm, to further decrease the number of intermediate
BDD nodes. Moreover, it is possible to combine with more sophisticated synthesis
techniques, such as compositional techniques, to substantially improve the algorithm
efficiency.
References
1. Ramadge, P.J.G., Wonham, W.M.: The Control of Discrete Event Systems. Proceedings of
the IEEE 77, 81-98 (1989)
2. Cassandras, C.G., Lafortune, S.: Introduction to Discrete Event Systems, 2nd edn. Springer,
Heidelberg (2008)
3. Balemi, S., Hoffmann, G.J., Gyugyi, P., Wong-Toi, H., Franklin, G.F.: Supervisory Control
of a Rapid Thermal Multiprocessor. IEEE Transactions on Automatic Control 38, 1040-1059
(1993)
4. Feng, L., Wonham, W.M., Thiagarajan, P.S.: Designing Communicating Transaction Pro-
cesses by Supervisory Control Theory. Formal Methods in System Design 30, 117-141
(2007)
5. Shoaei, M.R., Lennartson, B., Miremadi, S.: Automatic Generation of Controllers for
Collision-Free Flexible Manufacturing Systems. In: 6th IEEE Conference on Automation
Science and Engineering, pp. 368-373 (2010)
6. Akers, S.B.: Binary Decision Diagrams. IEEE Transactions on Computers 27, 509-516
(1978)
7. Bryant, R.E.: Symbolic Manipulation with Ordered Binary Decision Diagrams. ACM Com-
puting Surveys 24, 293-318 (1992)
8. Miremadi, S., Akesson, K., Lennartson, B.: Extraction and Representation of a Supervi-
sor Using Guards in Extended Finite Automata. In: 9th International Workshop on Discrete
Event Systems, pp. 193-199 (2008)
9. Hoare, C.A.R.: Communicating Sequential Processes. Communications of the ACM 21,
666-677 (1985)
