State Observation and Diagnosis of Discrete-Event SystemsDescribed by Stochastic Automata
Discrete Event Dynamic Systems
Discrete Event Dynamic Systems
Automating the Addition of Fault-Tolerance
FTRTFT '00 Proceedings of the 6th International Symposium on Formal Techniques in Real-Time and Fault-Tolerant Systems
WODES '02 Proceedings of the Sixth International Workshop on Discrete Event Systems (WODES'02)
Centralized Modular Diagnosis and the Phenomenon of Coupling
WODES '02 Proceedings of the Sixth International Workshop on Discrete Event Systems (WODES'02)
Synthesis of fault-tolerant concurrent programs
ACM Transactions on Programming Languages and Systems (TOPLAS)
Automated Synthesis of Multitolerance
DSN '04 Proceedings of the 2004 International Conference on Dependable Systems and Networks
Solvability of Centralized Supervisory Control Under Partial Observation
Discrete Event Dynamic Systems
Introduction to Discrete Event Systems
Introduction to Discrete Event Systems
Diagnosability Analysis of a Class of Hierarchical State Machines
Discrete Event Dynamic Systems
Automating the addition of fault tolerance with discrete controller synthesis
Formal Methods in System Design
Issues of Fault Diagnosis for Dynamic Systems
Issues of Fault Diagnosis for Dynamic Systems
Safe diagnosability for fault-tolerant supervision of discrete-event systems
Automatica (Journal of IFAC)
Model-based detection of routing events in discrete flow networks
Automatica (Journal of IFAC)
| Hi-index | 22.14 |
The aim of this paper is to deal with the problem of fault tolerant control in the framework of discrete event systems modeled as automata. A fault tolerant controller is a controller able to satisfy control specifications both in nominal operation and after the occurrence of a fault. This task is solved by means of a parameterized controller that is suitably updated on the basis of the information provided by online diagnostics: the supervisor actively reacts to the detection of a malfunctioning component in order to eventually meet degraded control specifications. Starting from an appropriate model of the system, we recall the notion of safe diagnosability as a necessary step in order to achieve fault tolerant control. We then introduce two new notions: (i) ''safe controllability'', which represents the capability, after the occurrence of a fault, of steering the system away from forbidden zones and (ii) ''active fault tolerant system'', which is the property of safely continuing operation after faults. Finally, we show how the problem can be solved using a general control architecture based on the use of special kind of diagnoser, called ''diagnosing controller'', which is used to safely detect faults and to switch between the nominal control policy and a bank of reconfigured control policies. A simple example is used to illustrate the new notions and the control architecture introduced in the paper.