Méthodologie de diagnostic et tolérance aux défauts de systèmes complexes

L'objectif de ce travail est de proposer une méthodologie de diagnostic et de tolérance aux défauts appliquée aux systèmes complexes. Dans cette étude, les défauts de capteurs et d'actionneurs sont considérés. Nous traitons également du problème d'instrumentation des systèmes complexes. Dans un premier temps, nous considérons la conception d'un réseau de capteurs minimal (d'un point de vue du nombre des capteurs) vérifiant l'observabilité du système. Le réseau minimal n'est pas robuste vis-à-vis des défauts des capteurs : la perte d'un capteur peut entraîner la perte d'observabilité du système. Nous proposons alors une approche répondant à ce problème. Nous proposons ensuite une méthodologie de conception d'un réseau de capteurs assurant la diagnosticabilité des défauts d'actionneurs des systèmes complexes. Les approches développées sont formulées sous forme de problèmes d'optimisation binaires non linéaires. Elles sont illustrées et validées en simulation sur un modèle réaliste de suspension active du véhicule.AIX-MARSEILLE3-BU Sc.St Jérô (130552102) / SudocSudocFranceF

Optimal sensor network for fault diagnosis using structural analysis

International audienceThis paper addresses the problem of instrumentation for fault detection and isolation in structured systems. The design of sensor networks is achieved by using structural analysis. This problem of sensor network design is formulated as nonlinear binary optimization problem. If the FDI problem is not solvable for an instrumented system, the strategy determines the additional sensors to be used to guarantee faults diagnosability. In addition, it is shown how to design a sensor network for non-instrumented systems while optimizing the number of sensors, the cost or the reliability of the network

Optimization-based reliable control allocation/reallocation design for over-actuated systems

International audienceCurrent solutions to deal with control objectives in over-actuated systems consist in distributing control efforts among redundant actuators. However, there is no or little consideration on the employed criteria to achieve such distribution. This paper proposes reliable control allocation methods where the objective is to manage control inputs in order to maintain system performance and at the same time, to guarantee an optimal overall system reliability. The reliable control allocation methods are posed as optimization problems incorporating system’s reliability. The effectiveness of proposed methods is demonstrated by using an unmanned fixed wing aircraft model

Fault-Tolerant Control Systems: Design and Practical Applications

International audienc

Fault-tolerant Control Systems: Design and Practical Applications

Fault-tolerant Control Systems reports the development of fault diagnosis and fault-tolerant control (FTC) methods with their application to real plants. After an introduction to fault diagnosis and FTC, a chapter on actuators and sensors in systems with varying degrees of nonlinearity leads to three chapters in which the design of FTC systems is given thorough coverage for real applications: (i) a winding machine typifying a subsystem in various sheet and film processes; (ii) a hydraulic three-tank system representative of those used widely in chemical plants; and (iii) an active suspension system demonstrating application in whole large-scale systems by splitting into subsystems.Actuator and sensor faults are accommodated within the control-law design and the integration of fault diagnosis models in the FTC systems described. Commentary is given on the recent results presented. Critical failures â the loss of system observability from total loss of a sensor and of controllability from complete loss of an actuator â are considered. Linearized systems around an operating point and nonlinear systems are discussed and illustrated. A complete simulation platform of the three-tank system, in closed-loop, with or without actuator and sensor faults, is provided for the use of the reader via download from www.springer.com/978-1-84882-652-6.With its emphasis on real application, Fault-tolerant Control Systems makes an important contribution to the literature on FTC and will be of significant assistance to practicing control engineers with problems of this nature to solve. The book will also be of use to academic researchers and graduate students interested in FTC, bringing to their attention the need to adapt their methods for implementation and suggesting ways in which this can be done

MajecSTIC'08 - Actes de la Sixième Manifestation des Jeunes Chercheurs en Sciences et Technologies de l\'Information et de la Communication

ISBN n° 978―2-9520712―9-1 Actes + clé USBNational audienceno abstrac

MajecSTIC'08 - Actes de la Sixième Manifestation des Jeunes Chercheurs en Sciences et Technologies de l\'Information et de la Communication

ISBN n° 978―2-9520712―9-1 Actes + clé USBNational audienceno abstrac

Optimal reliability design for over-actuated systems based on the MIT rule: Application to an octocopter helicopter testbed

International audienceThis paper addresses the problem of optimal reliability in over-actuated systems. Overloading an actuator decreases its overall lifetime and reduces its average performance over a long time. Therefore, performance and reliability are two conflicting requirements. While appropriate reliability is related to average loads, good performance is related to fast response and sufficient loads generated by actuators. Actuator redundancy allows to address both performance and reliability at the same time by properly allocating desired loads among redundant actuators. The main contribution of this paper is the on-line optimization of the overall plant reliability according to performance objective using an MIT (Massachusetts Institute of Technology) rule-based method. The effectiveness of the proposed method is illustrated through an experimental application to an octocopter helicopter testbed