Abstract
In this paper a hybrid approach is proposed for supervisory control of discrete event systems (DES) subject to forbidden states. Assuming that an uncontrolled bounded Petri net (PN) model of a (plant) DES and a set of forbidden state specifications are given, the proposed approach computes a maximally permissive and nonblocking closed-loop hybrid model. The first step is to simplify the given PN model by means of PN reduction rules. The simplified model and the specifications are then represented as buffers, and supervisory control theory (SCT) is applied to obtain a Ramadge–Wonham (RW) supervisor in the form of an automaton. After reduction of the latter’s state size by a ‘control congruence’, the simplified RW supervisor is represented by a so-called auto-net and coupled to the given uncontrolled PN plant model by means of inhibitor arcs to represent the disabling actions. The plant model and supervisor auto-net run concurrently, synchronizing on shared events. This procedure provides a maximally permissive and nonblocking ‘hybrid’ (mixed PN/automaton) closed-loop controlled system. The method is straightforward logically, graphically, and technologically. Its applicability is shown by two examples, one of them a workcell from the PN control literature.
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References
Ramadge PJ, Wonham WM (1986) Modular supervisory control of discrete event systems. In: Bensoussan A, Lions JL (eds) Proc. of the Seventh Int Conf on the Analysis and Optimization of Systems, Antibes, pp 202–214, lecture notes in control and optimization of systems vol 83. Springer, Berlin Heidelberg New York
Ramadge PJ, Wonham WM (1987) Supervisory control of a class of discrete event processes. SIAM J Control Optim 25(1):206–230
Ramadge PJ, Wonham WM (1987) Modular feedback logic for discrete event systems. SIAM J Control Optim 25(5):1202–1218
Wonham WM, Ramadge PJ (1987) On the supremal controllable sublanguage of a given language, SIAM J Control Optim 25(3):637–659
Wonham WM (2003) Notes on Control of Discrete-Event Systems. ECE Dept., University of Toronto. http://www.control.utoronto.ca/DES
Giua A (1996) PN techniques for supervisory control of discrete event systems. In Proc of 1st Int Workshop on Manuf and PNs, Osaka, Japan, June 1996, pp 1–21
Zurawski R, Zhou MC (1994) PNs and industrial applications: a tutorial. IEEE Trans Ind Electron 41(6):567–583
Giua A, DiCesare F, Silva M (1992) Generalized mutual exclusion constraints on nets with uncontrollable transitions. In Proc of IEEE Int Conf on Sys. Man and Cyber, Chicago, Illiois, USA, pp 974–979
Yamalidou K, Moody JO, Lemmon M, Antsaklis PJ (1996) Feedback control of PNs based on place invariants. Automatica 32(1):15–28
Moody JO, Antsaklis PJ (2000) PN supervisors for DES with uncontrollable and unobservable transitions. IEEE Trans Automat Control 45(3):462–476
Ghaffari A, Rezg N, Xie X (2003) Design of a live and maximally permissive PN controller using the theory of regions. IEEE Trans Robot Automat 19(1):137–142
Uzam M (2004) Synthesis of feedback control elements for discrete event systems using Petri net models and theory of regions. Int J Adv Manuf Tech 24(1–2):48–69
Uzam M (2002) An optimal deadlock prevention policy for flexible manufacturing systems using PN models with resources and the theory of regions. Int J Adv Manuf Tech 19(3):192–208
Uzam M (2004) The use of PN reduction approach for an optimal deadlock prevention policy for flexible manufacturing systems. Int J Adv Manuf Tech 23(3–4):204–219
Holloway LE, Krogh BH (1990) Synthesis of feedback control logic for a class of controlled PNs. IEEE Trans Automat Control 35(5):514–523
Boel RK, Ben-Naoum L, Breusegem VV (1995) On forbidden state problems for a class of controlled PNs. IEEE Trans Automat Control 40(10):1717–1731
Holloway LE, Guan X, Zhang L (1996) A generalization of state avoidance policies for controlled PNs. IEEE Trans Automat Contr 41(6):804–816
Chen H (1998) Net structure and control logic synthesis of controlled PNs. IEEE Trans Automat Control 43(10):1446–1451
Chen H (2000) Control synthesis of PNs based on s-decreases. Discret Event Dyn Syst 10(3):233–249
Ghaffari A, Rezg N, Xie X (2003) Feedback control logic for forbidden-state problems of marked graphs: application to a real manufacturing system. IEEE Trans Automat Control 48(1):18–29
Jones AH, Uzam M (1998) A formal technique for the synthesis of PN supervisors for discrete event systems. In Proc of the Int Conf on Control - CONTROL’98, University of Wales, Swansea, UK, 1–4 Sept 1998, pp 845–852
Uzam M, Jones AH, Yücel İ (2000) Using a Petri-net-based approach for the real-time control of an experimental manufacturing system. Int J Adv Manuf Tech 16(7):498–515
Murata T (1989) Petri nets: properties, analysis and application. Proc IEEE 44:541–579
Su R, Wonham WM (2004) Supervisor reduction for discrete event systems. Discret Event Dyn Syst 14(1):31–53
Krogh BH, Holloway LE (1991) Synthesis of feedback control logic for discrete manufacturing systems. Automatica 27(4):641–651
Zhou MC, Jeng MD (1998) Modeling, analysis, simulation, scheduling, and control of semiconductor manufacturing systems: a PN approach. IEEE Trans Semicond Manuf 11(3):333–357
Lee KH, Favrel J (1985) Hierarchical reduction method for analysis and decomposition of PNs. IEEE Trans Syst Man Cybern SMC 15:272–280
Silva M (1985) Las redes de Petri en la automatica y la informatica. Editorial AC, Madrid, Spain
TCT (2004) A software tool supporting SCT. Systems Control Group, ECE Dept, University of Toronto. www.control.utoronto.ca/DES
Wonham WM (2003) Supervisory control theory: models and methods. In Proc. ATPN - Workshop on Discrete-Event Systems Control, 24th International Conference on Application Theory of Petri Nets (ATPN 2003), Eindhoven, The Netherlands, pp 1–14, June 2003
INA (2003) Integrated Net Analyzer. A software tool for analysis of Petri nets, Version 2.2. http://www.informatik.hu-berlin.de/∼starke/ina.html
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Uzam, M., Wonham, W. A hybrid approach to supervisory control of discrete event systems coupling RW supervisors to Petri nets. Int J Adv Manuf Technol 28, 747–760 (2006). https://doi.org/10.1007/s00170-004-2426-7
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DOI: https://doi.org/10.1007/s00170-004-2426-7