Authors: Niemann, Henrik; Poulsen, Niels Kjølstad

Abstract: A new approach for active fault diagnosis (AFD) in closed-loop systems is considered in this paper. This developed AFD approach is based on reduced model information. It is shown that it is possible to apply the AFD approach based on gain and phase information at a single frequency only. This means that simple models can be applied for the residual generation. The approach is demonstrated by an example.

Keywords: Linear and robust methods; Signal and identification-based methods

Identifier: 10.3182/20090630-4-ES-2003.00159

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Tabatabaeipour, Seyedmojtaba; Ravn, Anders P.; Bak, Thomas; Izadi-Zamanabadi, Roozbeh

Abstract: A method for active fault diagnosis of linear discrete time hybrid systems is presented. The algorithm generates appropriate test signals that can be used for sanity check during system commissioning or later in the normal phase to detect faults which are impossible to detect by means of passive diagnosis methods because of regulatory actions of the controller. The algorithm is illustrated on a two tank benchmark example.

Keywords: Discrete-event and hybrid systems; Fault-tolerant control

Identifier: 10.3182/20090630-4-ES-2003.00035

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Dziekan, Lukasz; Witczak, Marcin; Korbicz, Jozef

Abstract: In this paper, an active FTC strategy is presented. First, it is developed in the context of linear systems and then it is extended to Takagi-Sugeno fuzzy systems. The key contribution of the proposed approach is an integrated FTC design procedure of the fault identification and fault-tolerant control schemes. Fault identification is based on the use of an observer. While, the FTC controller is implemented as a state feedback controller. This controller is designed such that it can stabilize the faulty plant using Lyapunov theory and LMIs.

Keywords: Fault-tolerant control; Neuro-fuzzy methods

Identifier: 10.3182/20090630-4-ES-2003.00075

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Fair, Martene; Campbell, Stephen L

Abstract: The problem of detecting small parameter variations in linear uncertain systems due to incipient faults, by injecting an input signal to enhance detection is considered. Unlike previous work where it is usually assumed that there is only one fault, in this paper we allow for two faults which is a natural assumption in the incipient case. A constructive method for the construction of an optimal input signal for achieving guaranteed detection with specified precision is presented in the discrete model case. The method is an extension of the multi-model approach used for the construction of auxiliary signals for failure detection, however, new technical issues must be addressed.

Keywords: Signal and identification-based methods; Linear and robust methods; Discrete-event and hybrid systems

Identifier: 10.3182/20090630-4-ES-2003.00095

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Esna Ashari, Alireza; Nikoukhah, Ramine; Campbell, Steve

Abstract: Active failure detection consists of finding an input signal(auxiliary signal) such that its use allows perfect detection of faults in a multi-model framework. In this paper we consider the problem of optimal auxiliary signal design for a linear uncertain system controlled by a linear feedback. The optimization criterion used is a worst case quadratic cost, which in practice is the same cost used for the design of the controller. Even though we suppose that the feedback controller is given, the methodology developed here should be useful for feedback design to achieve both control and fault detection objectives.

Keywords: Signal and identification-based methods; Linear and robust methods

Identifier: 10.3182/20090630-4-ES-2003.00097

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Gaspar, Peter; Szabo, Zoltan; Bokor, Jozsef

Abstract: This paper focuses on the derivation of a Fault Detection and Identification (FDI) filter for the detection of the faults that might occur during the operation of the actuator built in the suspension system. The design of the proposed FDI filter is based on dynamic inversion and on a Linear Parameter Varying (LPV) observer design. To improve the performance properties of heavy vehicles, i.e. to reduce the risk of rollovers, improve passenger comfort and road holding, a reconfigurable fault tolerant control design of the active suspensions and the active brake is performed. However when a fault (loss in effectiveness) occurs at one of the suspension actuators a further reconfiguration is needed in order to maintain the same performance level. The proposed reconfiguration scheme is based on an LPV method that uses the fault information as one of the scheduling variables. The LPV based control design and the operation of the control mechanism are demonstrated through a vehicle maneuver.

Keywords: Fault-tolerant control; Automotive applications; Linear and robust methods

Identifier: 10.3182/20090630-4-ES-2003.00232

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Bosche, Jerome; El hajjaji, Ahmed; Rabhi, Abdelhamid

Abstract: This paper presents Fault-Tolerant Control (FTC) architecture for vehicle dynamics represented by an LPV (Linear Parameter Varying) model with actuator failures. The type of faults considered in this work is total or partial loss of actuator effectiveness. This method does not need any on-line fault estimation, detection or identification mechanism. The proposed approach is applied to the actuator fault tolerant control of vehicle dynamics. It is based on the resolution of LMI, using the concept of Dc-stability and involving PDLM (Parameter-Dependent Lyapunov Matrix). In order to highlight the performance of the proposed control algorithm, numerical simulations are performed.

Keywords: Automotive applications; Fault-tolerant control; Linear and robust methods

Identifier: 10.3182/20090630-4-ES-2003.00182

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Steffen, Thomas; Zolotas, Argyrios; Dixon, Roger; Goodall, R.M.

Abstract: The High Redundancy Actuator project deals with the construction of an actuator using many redundant actuation elements. Whilst this promises a high degree of fault tolerance, the high number of components poses a unique challenge from a control perspective, especially when actuation elements are used in series. This paper describes how an adaptive control scheme can be used to deal with faults in a High Redundancy Actuator. This is based on previous results leading to a simplified model of the HRA with serial elements. In case of the fault, the parameters change, but the otherwise the deviation from the simplified model is minimal. This approach has two benefits. For one, it can restore the original system dynamics even after a fault has occurred. The parameter estimate can also be used for health monitoring purposes, because it reflects the number of effective faults in the HRA.

Keywords: Fault-tolerant control; Nonlinear methods; Sensor and actuator faults

Identifier: 10.3182/20090630-4-ES-2003.00258

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Hajiyev, Chingiz; Soken, Halil Ersin

Abstract: In general case, as an algorithm for estimating the parameters of a linear system, Kalman filter can be utilized without any problem. However, when there is a malfunction in the estimation system, the filter fails and the outputs become inaccurate. In this paper, an Adaptive Kalman Filter with multiple fading factors based gain correction for the case of malfunctions in the estimation system is presented. By the use of an adaptive matrix constituted of multiple fading factors, faulty measurements are taken into consideration with small weight and the estimation errors are corrected without affecting the good estimation characteristic of the remaining process. Adaptive Kalman Filter algorithm is tested by simulations for the implementation in the navigation system of an UAV platform. The filter performance has been evaluated for different kinds of measurement malfunctions.

Keywords: Aerospace applications; Sensor and actuator faults; Fault-tolerant control

Identifier: 10.3182/20090630-4-ES-2003.00013

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Alves Jr, Marco

Abstract: Fault tolerant control of complex systems has received considerable attention in the latest years and it has been considered to a variety of systems with high critical and stringent requirements of dependability, including industrial plants, Unmanned Air Vehicles (UAVs) and medical equipments, among others. In this work, adaptive and robust methods are combined to yield a control scheme able to deal with uncertainties, parameters variations and some classes of faults on the system. The key idea is to add to the robust controller output a second control signal generated by an adaptive artificial neural network capable of compensating a wide range of perturbations, uncertainties, and faults, so that adequate performance characteristics of the main control loop is maintained. As an example, a controller is designed for a four rotor UAV model.

Keywords: Fault-tolerant control; Neuro-fuzzy methods; Sensor and actuator faults

Identifier: 10.3182/20090630-4-ES-2003.00023

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Yin, Shen; Naik, Amol; Ding, Steven X.

Abstract: Motivated by data-driven design of fault detection system, a recursive algorithm is developed for updating the parity relation within the framework of subspace identification methods (SIM). The presented recursive algorithm benefits from the signal processing methods for noise subspace tracking to reduce the computationally burdensome updating of singular value decomposition (SVD), which is a crucial step in SIM. Based on the recursive updated parity relation, the residual generator for the fault detection purpose is constructed and the issues of residual evaluation and threshold computation are discussed further. The adaptive process monitoring scheme that integrates the aforementioned issues, is proposed and tested on the laboratory three-tank-system.

Keywords: Signal and identification-based methods; Sensor and actuator faults

Identifier: 10.3182/20090630-4-ES-2003.00156

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Montes de Oca, Saúl; Puig, Vicenc

Abstract: In this paper, adaptive threshold generation for robust fault detection of nonlinear system described by means of Linear Parameter Varying (LPV) model is analyzed. Uncertainties due to parameter variations are considered unknown but bounded by intervals. Their effect is addressed using an interval LPV observer based on zonotopes. The design procedure of this observer is implemented via pole placement using LMI. The optimal advanced threshold is generated by evaluating the worst-case residual's energy evolution in the time domain. When the advanced adaptive threshold is used, the minimum detectable fault is characterized. Finally, an application example based on two-degree freedom helicopter will be used to assess the validity of the proposed approach.

Keywords: Linear and robust methods; Aerospace applications

Identifier: 10.3182/20090630-4-ES-2003.00074

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Sayed Mouchaweh, Moamar

Abstract: The behavior of a dynamic system assumes different states over the time. In Pattern Recognition methods, each state is represented by a set of similar patterns forming restricted regions in the feature space, called classes. Recognizing the state, or class, of a new incoming pattern is performed using a membership function. In this paper, we propose to develop the supervised classification method Fuzzy Pattern Matching to be in addition a non supervised one. The goal is to monitor dynamic systems with a limited prior knowledge about their functioning. The detection of the occurrence of new states as well as the reinforcement of the estimation of their membership functions are performed online thanks to the combination of supervised and non supervised classification modes. No information in advance about the shape of classes or their number is required to achieve this detection and estimation reinforcement.

Keywords: Statistical methods

Identifier: 10.3182/20090630-4-ES-2003.00085

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Goupil, Philippe

Abstract: This paper deals with industrial practices and strategies for Fault Tolerant Control (FTC) and Fault Detection and Isolation (FDI) in aircraft by focusing mainly on a typical Airbus Electrical Flight Control System (EFCS). This system is a safety-critical one in the sense that catastrophic consequences may result from its failures. It is designed to meet very stringent requirements in terms of safety, availability and reliability that characterized the system dependability. Fault tolerance is designed into the system by the use of stringent processes and rules, which are summarized in the paper. The strategy for monitoring (fault detection) of the system components, as a part of the design for fault tolerance, is also described in this paper. Real application examples and implementation methodology are outlined. Finally, future trends and challenges are presented.

Keywords: Aerospace applications; Fault-tolerant control; Sensor and actuator faults

Identifier: 10.3182/20090630-4-ES-2003.00094

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Ding, Steven X.; Yin, Shen; Zhang, Ping; Ding, E.L.; Naik, Amol

Abstract: This paper addresses data-driven design and implementation of adaptive observer based residual generators for discrete-time systems. The basic idea behind this study is the application of an one-to-one mapping between a parity vector and the solution of Luenberger equations and the data-driven identification of parity space. For the realization of the adaptive residual generation, standard adaptive technique is applied. The proposed approach is demonstrated on the laboratory three-tank-system.

Keywords: Signal and identification-based methods; PCA-based methods; Linear and robust methods

Identifier: 10.3182/20090630-4-ES-2003.00155

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Izadi, Iman; Shah, Sirish; Shook, David; Chen, Tongwen

Abstract: Alarms are essential in every process, system and industrial complex. They are configured to notify the operators about any abnormal situation in the process. In practice, operators receive far more false and nuisance alarms than valid and useful alarms. In this paper, an overview on alarm analysis and design is given. Some of the reasons for false and nuisance alarms are discussed and a few solutions to reduce them are studied. False alarm rate, missed alarm rate and detection delay trade-offs in alarm design are also discussed.

Keywords: Statistical methods; Sensor and actuator faults; PCA-based methods

Identifier: 10.3182/20090630-4-ES-2003.00107

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Stoustrup, Jakob

Abstract: An active fault diagnosis method for additive, parametric or multiplicative faults is proposed. It is assumed that the system considered is controlled by an observer based controller. The method is then based on a number of alternate observers, each designed to be sensitive to one or more faults. Periodically, the observer part of the controlleris changed into the sequence of fault sensitive observers. This is done in a way that guarantees continuity of transition and global stability using a recent result on observer parameterization. The proposed active fault diagnosis method distinguishes itself from the existing literature in terms of not relying on an exogenous excitation signal. An illustrative example based on a drag racing vehicle is given.

Keywords: Linear and robust methods; Automotive applications; Sensor and actuator faults

Identifier: 10.3182/20090630-4-ES-2003.00098

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Shi, Huaitao; Liu, Jianchang; Yingwei, Zhang

Abstract: An optimized kernel principal component analysis based on chaotic particle swarm optimization method (CPSO-KPCA) is put forward in this paper. The improved method adequately makes use of the characteristics of normal data and fault data to optimize the parameters of the mixture kernel function through chaotic particle swarm optimization so that the optimal nonlinear feature can be discovered and nonlinear fault can be detected accurately. Based on monitoring statistics charts in the feature space, this method is applied to fault detection in rolling process. Practical application shows that the presented method has higher accuracy in fault detection.

Keywords: PCA-based methods; Nonlinear methods; Other applications

Identifier: 10.3182/20090630-4-ES-2003.00139

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Biswas, Gautam; Koutsoukos, Xenofon; Pulido, Belarmino; Bregon, Anibal

Abstract: The FDI and DX communities have developed complementary approaches that exploit structural relations in the system model to find efficient solutions for the residual generation and residual evaluation steps in fault detection and isolation in dynamic systems. This paper compares three different structural techniques, two from the DX community and one from the FDI community. To simplify our comparison, we start with a common modeling approach that employs bond graphs. We describe the residual generation methods used by the three approaches, and apply them to a standard three tank configuration to demonstrate their diagnostic ability for continuous, nonlinear systems.

Keywords: Structural analysis; Nonlinear methods

Identifier: 10.3182/20090630-4-ES-2003.00242

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Pucel, Xavier; Trave-Massuyes, Louise; Pencolé, Y.

Abstract: This paper provides a new definition of diagnosability, that allows one to check the diagnosability of any set of system states, and by extension of properties that depend on the system state. The existing definitions and approaches for checking diagnosability apply to faults or sets of faults, and comparison shows that the new definition generalizes the existing ones. This new definition is applied to repair preconditions, and an example shows how this brings complementary information compared to classical fault diagnosability.

Keywords: Dependability; Sensor and actuator faults; Fault-tolerant control

Identifier: 10.3182/20090630-4-ES-2003.00016

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Ciubotaru, Bogdan D.; Staroswiecki, Marcel

Abstract: Linear quadratic fault tolerant control is addressed. Under process and/or actuator faults, both fault accommodation and system reconfiguration procedures need the controller to be redesigned, which amounts to solving the algebraic Riccati equation associated with the post- fault system model. To overcome the risks of system instability and/or control inadmissibility that might result from the fault detection and isolation delay and the computation time of the post-fault control law, two progressive accommodation strategies, namely Newton-Kleinman and Matrix-Sign-Function, are investigated. The longitudinal control of an aircraft under actuator and structural faults is used to illustrate the approaches with respect to the handling quality constraints.

Keywords: Fault-tolerant control; Aerospace applications

Identifier: 10.3182/20090630-4-ES-2003.00146

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Håkan, Warnquist; Pernestål, Anna; Nyberg, Mattias

Abstract: We consider computer assisted troubleshooting of complex systems, for example of a vehicle at a workshop. The objective is to identify the cause of a failure and repair a system at as low expected cost as possible. Three main challenges are: the need for disassembling the system during troubleshooting, the difficulty to verify that the system is fault free, and the dependencies in between components and observations. We present a method that can return a response anytime, which allows us to obtain the best result given the available time. The work is based on a case study of an auxiliary braking system of a modern truck. We highlight practical issues related to model building and troubleshooting in a real environment.

Keywords: Automotive applications; Electro-mechanical applications

Identifier: 10.3182/20090630-4-ES-2003.00212

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Kondaveeti, Sandeep Reddy; Shah, Sirish; Izadi, Iman

Abstract: Ever since the introduction of Distributed Control Systems (DCS), there has been little motivation for limiting the number of alarms that could be con¯gured for process monitoring. As a result, plant operators are overwhelmed with many alarms during process upsets. Although a handful of these alarms are informative, many of them are a nuisance to the operator. However, all the alarms need to be acknowledged. Generally, check limits on univariate alarms are based on statistical quality control (three sigma limits, also known as Shewhart charts). While annunciating a univariate alarm on a particular variable, the information from other variables is often ignored. Modern day process plants have variables which are highly correlated. This correlation structure can be exploited in the efficient management of alarms. This work demonstrates the advantages of monitoring the PCA based T2 and Q statistic over individual process variables. Monitoring these higher level statistics will not only reduce the false alarm and missed alarm rates but also reduces the detection latency which is one of the main drawbacks of monitoring a filtered variable. Two simulation examples are shown to illustrate the utility of the proposed method.

Keywords: Statistical methods; Sensor and actuator faults; Chemical applications

Identifier: 10.3182/20090630-4-ES-2003.00109

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Ma, Jianping; Jiang, Jin

Abstract: The nuclear power industry has started using Fault Detection and Diagnosis (FDD) in Nuclear Power Plants (NPPs) to improve the reliability and availability of the power plants. Many techniques have been applied for a wide range of key systems in nuclear power plants. In this paper, six areas of application of FDD in NPPs are introduced. Some chosen methods for those applications are briefly summarized.

Keywords: Power systems applications; Dependability

Identifier: 10.3182/20090630-4-ES-2003.00189

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009

Authors: Provan, Gregory

Abstract: For applications in which computing the set of all diagnoses is important, algorithms that compile the system model, such as the ATMS, are well-known. However, the space- and time-complexity of such approaches can be prohibitively large. We show how we can use a preference function over the space of diagnoses to develop approximation algorithms for computing the most-preferred diagnoses (MPD). We show that the MPD problem can be approximated by greedy algorithms such that the approximate set of diagnoses is within (1-1/e) of the exact set of diagnoses. We demonstrate how the MPD problem can be solved for on-line diagnosis using a fast stochastic diagnosis engine, and by compilation approaches using prime implicant and DNNF compilation languages. We present empirical evidence that the compilation algorithms enable space reductions of several orders-of-magnitude over the full compilation, while losing relatively little query completeness.

Keywords: Signal and identification-based methods

Identifier: 10.3182/20090630-4-ES-2003.00014

Conference: 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes

Location: Sants Hotel, Spain

Start Date: Tue Jun 30 2009 - End Date: Fri Jul 03 2009