Decision with Bayesian network in the concurrent faults event

The purpose of this article is to present a new method for process diagnosis with Bayesian network. The interest of this method is to propose a new structure of Bayesian network allowing to diagnose a system with the model-based framework or with the data-driven framework. A particular interest of the proposed approach is the use of continuous nodes in the network in order to evaluate the status of the process. The effectiveness and performances of the method are illustrated on a heating water process corrupted by various faults

Using Bayesian networks for decision in the simultaneous faults case

The purpose of this article is to present a new method for process diagnosis with Bayesian network. The interest of this method is to propose a new structure of Bayesian network allowing to diagnose a system with the model-based framework or with the data-driven framework. A particular interest of the proposed approach is the use of continuous nodes in the network in order to evaluate the status of the process. The effectiveness and performances of the method are illustrated on a heating water process corrupted by various faults

Fault tolerant control design for polytopic LPV systems

This paper deals with a Fault Tolerant Control (FTC) strategy for polytopic Linear Parameter Varying (LPV) systems. The main contribution consists in the design of a Static Output Feedback (SOF) dedicated to such systems in the presence of multiple actuator faults/failures. The controllers are synthesized through Linear Matrix Inequalities (LMIs) in both faultfree and faulty cases in order to preserve the system closed-loop stability. Hence, this paper provides a new sufficient (but not necessary) condition for the solvability of the stabilizing output feedback control problem. An example illustrates the effectiveness and performances of the proposed FTC method

Actuator fault tolerant control design based on a reconfigurable reference input

The prospective work reported in this paper explores a new approach to enhance the performance of an active fault tolerant control system. The proposed technique is based on a modified recovery/trajectory control system in which a reconfigurable reference input is considered when performance degradation occurs in the system due to faults in actuator dynamics. An added value of this work is to reduce the energy spent to achieve the desired closed-loop performance. This work is justified by the need of maintaining a reliable system in a dynamical way in order to achieve a mission by an autonomous system, e.g., a launcher, a satellite, a submarine, etc. The effectiveness is illustrated using a three-tank system for slowly varying reference inputs corrupted by actuators faults

Reconfigurability analysis for reliable fault-tolerant control design

In this paper the integration of reliability evaluation in reconfigurability analysis of a fault-tolerant control system is considered. The aim of this work is to contribute to reliable fault-tolerant control design. The admissibility of control reconfigurability is analyzed with respect to reliability requirements. This analysis shows the relationship between reliability and control reconfigurability defined generally through Gramian controllability. An admissible solution for reconfigurability is proposed according to reliability evaluation based on energy consumption under degraded functional conditions. The proposed study is illustrated with a flight control application

An active fault-tolerant control framework against actuator stuck failures under input saturations

In this paper, a control framework including active fault-tolerant control (FTC) and reference redesign is developed subject to actuator stuck failures under input saturations. FTC synthesis and reference redesign approaches are proposed to guarantee post-fault system safety and reference reachability. Then, these features are analyzed under both actuator stuck failures and constraints before fault-tolerant controller switches. As the main contribution, actuator stuck failures and constraints are unified so that they can be easily considered simultaneously. By means of transforming stuck failures into actuator constraints, the post-fault system can be regarded as an equivalent system with only asymmetrical actuator constraints. Thus, methods against actuator saturations can be used to guarantee regional stability and produce the stability region. Based on this region, stuck compensation is analyzed. Specifically, an unstable open-loop system is considered, which is more challenging. Furthermore, the method is extended to a set-point tracking problem where the reachability of the original reference can be evaluated. Then, a new optimal reference will be computed for the post-fault system if the original one is unreachable. Finally, simulation examples are shown to illustrate the theoretical results

Frequency-shaping observer-based controller design for actuator degradation: Application to suspension system

International audienceThe main contribution of this paper is a methodology, derived from H2 cost functional, Parseval’s Theorem in controller design and the principle of unknown input observer, for the estimation and accommodation of polynomial actuator degradation. In this design, the observer-based controller, integrated with a frequency-shaping filter and a state-feedback compensator, attenuates the disturbance influence on observer estimation and maintains the system stability. Furthermore, due to its simplicity, industrial engineers and readers can easily apply the proposed method to health maintenance system. Finally, an application to suspension system is illustrated to highlight the performance of the proposed method

Fault-Tolerant Control Design for over-actuated System conditioned by Reliability: a Drinking Water Network Application.

Drinking water management in urban areas is a subject of increasing concern as cities grow Baumann et al. (1997). Limited water supplies, conservation and sustainability policies, as well as the infrastructure complexity for meeting consumer demands with appropriate flow, pressure and quality levels make water management a challenging control problem. Fault-tolerant control (FTC) is introduced in order to address the growing demand of plant availability. The aim of FTC is to keep plant available by the ability to achieve the objectives that have been specified in faulty behaviour Noura et al. (2009). The FTC is based on material or functional redundancy. For overactuated systems, control allocation is implemented to distribute the objectives over the available solutions to control the system. Recently Khelassi et al. (2010) propose to integrate the reliability of the actuators in the control allocation in order to preserve the health of the actuators and the availability of the system both in the nominal behavior and in the presence of actuator faults. Nevertheless, the SF is not used in this method, therefore the solution minimizes the actuator’s failure and contributes to increase the overall system reliability but is not based its optimization. Our proposal consists mainly in formalizing a standard SF model with a BN and demonstrating the usability of this model in FTC problem of overactuated system. The paper is organized as follows: In Section 2, a solution for a reliable control of overactuated systems is presented based on the on-line actuators reliability indihal-00728248