this paper deals with the problem of forbidden states in discrete event systems modeled by petri net. to avoid the forbidden states, some constraints which are called generalized mutual exclusion constraints can be assigned to them. enforcing these constraints on the system can be performed using control places. however, when the number of these constraints is large, a large number of control p...

A Generalized Mutual Exclusion Constraint (GMEC) is a linear constraint that limits the weighted sum of tokens in a subset of places of a place/transition net system. The corresponding controller takes the simple form of a monitor place that can be added to the net to obtain the closed-loop system. In this paper we extend this approach to the case of colored Petri nets, showing that a colored G...

This paper presents two new results on the problem of determining a set of decentralized controllers for place/transition nets to enforce a global specification on the net behavior. Both the global specification and the decentralized specifications are given in terms of Generalized Mutual Exclusion Constraints (GMECs). First, an algorithm to select a decentralized specification that finds a com...

This paper deals with the problem of enforcing generalized mutual exclusion constraints (GMEC) on place/transition nets with uncontrollable transitions. An efficient control synthesis technique, that has been proposed in the literature, is to enforce GMEC constraints by introducing monitor places to create suitable place invariants. The method has been shown to be maximally permissive and to gi...

In this paper a special type of nonlinear marking specifications called stair generalized mutual exclusion constraints (stair-GMECs) is defined. A stair-GMEC can be represented by an inequality whose left-hand is a linear combination of floor functions. Stair-GMECs have a higher modeling power than classical GMECs and can model legal marking sets that cannot be defined by OR-AND GMECs. We propo...

This paper discusses the fault tolerant control problem for discrete event systems modeled by Petri nets. The fault is represented by the unobservable transitions. Firstly, an observer-based fault diagnosis method is proposed to estimate the marking with unknown initial markings and meanwhile, to diagnose the faulty behavior. Then, an adaptive fault tolerant controller is designed to maintain t...

In this paper we deal with the problem of controlling a Petri net whose marking cannot be measured but is estimated using an observer. The control objective is that of enforcing a set of generalized mutual exclusion constraints (GMEC) and all transitions are assumed to be controllable. Clearly, the use of marking estimates may significantly reduce the performance of the closed-loop system and m...

This paper deals with the problem of forbidden states in discrete event systems modeled by Petri Net. To avoid the forbidden states, some constraints which are called Generalized Mutual Exclusion Constraints can be assigned to them. Enforcing these constraints on the system can be performed using control places. However, when the number of these constraints is large, a large number of control p...

We propose a general and uniform modal framework for the Event Calculus (EC) and its skeptical and credolous variants. The resulting temporal formalism, called the Generalized Modal Event Calculus (GMEC), extends considerably the expressive power of EC when information about the ordering of events is incomplete. It provides means of inquiring about the evolution of the maximal validity interval...

This paper addresses the forbidden-state problem of general marked graphs with uncontrollable transitions. The models need not to be safe nor cyclic. Control requirements are expressed as the conjunction of general mutual exclusion constraints (GMEC) of markings of so-called critical places. Structural properties such as influence paths and influence zones are proposed to perform the worst-case...