The Ramadge-Wonham framework for control of discrete event systems is augmented with timing features by use Ostroff's semantics timed transition models. It shown that the RW concept controllability and existence maximally permissive supervisory controls can be suitably generalized. enhanced setting admits subsystem composition forcible as an preempts tick a global clock. An example simple manufacturing cell illustrates how new used to solve synthesis problems which may include logic-based,...

The manufacturing environment has changed dramatically. In the past, systems were sufficiently simple, in most cases, to permit use of intuitive and informal solutions development supervisory control systems. increasing level automation, integration, flexibility encountered automated renders formal approaches system a necessity, controlled-automata based approach considered this work is one such approach. It offers important advantages over other approaches. guarantees that: i) resulting...

In this paper, we present a hierarchical method that decomposes system into two subsystems, and restricts the interaction of subsystems by means an interface. We definitions for types interfaces [represented as discrete-event systems (DESs)], define set interface consistency properties can be used to verify if DES is nonblocking controllable. Each clause verified using only one subsystems; thus, complete model never needs constructed, offering potentially significant savings in computational...

This article presents new approaches to system verification and synthesis based on subsystem the novel combined use of counterexamples heuristics identify suitable subsystems incrementally. The scope safety properties considered is limited behavioral inclusion controllability. examples provide a comparison presented with straightforward state exploration an understanding their applicability in industrial context.

A supervisory control system, based on controlled automata concepts, is developed for the automated manufacturing system of Atelier Interetablissement de Productique (AIP, Dauphine-Savoie, France). The approach adopted offers important advantages over other existing approaches: mainly (i) resulting behaviours are guaranteed not to contradict behavioural specifications and be nonblocking, (ii) maximally permissive within specifications. implementation considers modular supervision under...

We introduce a modular architecture for diagnosis in the framework of discrete event systems. The is best suited systems with multiple interacting components. suggest to use local at each component and provide sufficient conditions so that global system behavior can be diagnosed using these diagnoses. Moreover, context presented architecture, we discuss an incremental algorithm check diagnosability Sampath et al. (1995). suggested has advantage being more computationally efficient than one...

An approach to the design of modular supervisory control strategies based on a framework for modeling and discrete-event systems is presented. As centralized supervision, allows consideration logic-based specifications, control-enforcement-related constraints, temporal utility optimality behavioral specifications. It yields that are least restrictive within given which correct by construction offers all advantages distributed control. Under conditions, supervision techniques presented...

The timed discrete-event system framework admits disablement and forcing as means of control, well the treatment hard temporal behavioural constraints. notion modular supervisory control systems proposed by Wonham-Ramadge (1988) is extended to this framework. approach consists dividing overall task into two or more subtasks, with resulting individual subsupervisors being run concurrently implement a solution original problem, if necessary under assumption partial observation. design...

We present a hierarchical method that decomposes system into two subsystems, and restricts the interaction of subsystems by means an interface. definition for interface, define set interface consistency properties can be used to verify if discrete-event is nonblocking controllable. Each clause verified using only one subsystems; thus complete model never needs constructed, offering significant savings in computational effort. Additionally, development clean interfaces facilitates re-use...

The framework given by P.J. Ramadge and W.M. Wonham (SIAM J. Control Optim., Vol. 25, no.1, p.206-30, 1987) for control of discrete event systems is augmented with timing features use Ostroff's semantics timed transition models (1989, 1990). It shown that the corresponding concept controllability, existence minimally restrictive supervisory controls can be suitably generalized. enhanced setting admits subsystem composition, forcible as an preempts tick a global clock. An example simple...

The authors propose an approach to workcell supervisory control strategy design based on the theory for discrete event systems (DES). A framework modeling and of timed DES is presented, in which concept forcing as a means introduced, where hard temporal behavior specifications may be treated. Within this framework, strategies are designed according production subject enforcement constraints.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An incremental approach to system verification is proposed, for behaviours and safety properties described by means of finite-string languages finite-state automata. Properties are verified with respect subsystems the overall system, nevertheless allowing assertions be made about entire satisfying such properties. The proposed considers satisfaction properties, controllability, synthesis as successive steps. Furthermore, it allows augmentation verified: after each step, either desired...

This paper discusses ongoing research on automatically configurable distributed control systems. We are investigating the use of networks relatively small controllers that contain intelligence and communication capabilities to perform factory automation. These systems expected be more robust, adaptable flexible than conventional designs. To achieve these benefits, fundamental changes in underlying system architecture needed. The is divided into two portions: infrastructure algorithms....

We analyze an active leveler designed for automotive applications. The objective of the system is to maintain height car body a fixed value, despite changes in loads and driving conditions. paper propose verification method checking that certain design specifications, or performances are achieved. able compute exact bounds on maximum suspension deflection given model road disturbance. motivation this work comes from disappointing results Stanner et al. (1997) where problem was approached by...

In this paper we present a hierarchical method that breaks up plant into two subsystems, and restricts the interaction of subsystems by means an interface. We definition for interface, define set interface consistency properties can be used to verify if discrete-event system (DES) is non-blocking. Each clause verified using only one subsystems; thus complete model never needs constructed.

In this work, we study the class of real-time discrete-event systems modeled by finite interval automata, i.e., a state automaton where each transition is labeled an event and interval. The automata interpreted over discrete time models corresponds exactly to tick automata. An domain construction synchronous product provided that encodes in domain. This avoids explicit enumeration clock ticks required timed formalism. To increase expressive power also distinguish preempting transitions from...

Since the timed supervisory control framework was proposed, it has been adopted in many subsequent developments various areas. Yet, mechanism of explicitly enumerating time terms sequences ticks significantly increases number states, causing major computational challenges supervisor synthesis. To overcome this challenge, work we develop a theory time-interval discrete event systems, whereby intervals are used to compactly encode ticks. By introducing concepts free and coercive (interval)...

In this paper we model an operational planning and scheduling problem under multiple job deadlines in a time-weighted automaton framework. We first present method to determine whether all given specifications can be met by computing supremal controllable satisfaction sublanguage. When sublanguage is not empty, compute one of its sublanguages that ensures the minimum total earliness adding proper delays. sublangauge will minimal sets need relaxed.

Error detection and recovery are essential aspects of the continuous safe operation automated manufacturing systems. In past these were sufficiently simple to allow informal approaches supervisory control therefore error

Brandin and Wonham introduced a timed supervisory control framework in 1994. The key innovations arguably were the introduction of tick events to model passing time, event forcing. enriches Ramadge-Wonham framework, albeit with cost deal high modeling synthesis complexities due explicit enumeration ticks. To address these challenges, presented forgoes instead relies on time-interval automata whose transitions are labeled by equipped discrete time-intervals. In contrast resetting mechanism...

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 contribute fault-tolerance terms operational safety. The proposed formalization introduces at a high level, switching function mechanism forcing states. After brief presentation usual techniques domain automated manufacturing systems (AMS), extension automata theory by...

An artificial-intelligence technique, namely blackboard architecture, is used to confront the problem of controlling and supervising groups lifts. With construction high-rise buildings, transportation efficiency has become an important consideration in lift systems design. The variety constraints, especially constraints related traffic, make design traffic supervision control a complex task. paper divided into two main sections: first considers development shell system presented; second...

A novel approach to the control and supervision problem for groups of elevators has been successfully developed tested by simulation. The supervisory tasks have implemented using blackboard solving in which several knowledge sources cooperate, providing a very flexible framework. shell unit this study uses dual-level structure comprehensive data source descriptors. modularity system allows strategies be modified or extended simply adjoining additional existing ones tuning different...