Observer-based Fault Detection Filter Research Articles

A randomized algorithm based approach to fault detection for uncertain systems subject to deception attack

This paper presents a fault detection strategy for discrete uncertain systems subject to deception attack based on the probabilistic framework. Probabilistic parameter models are utilized for characterizing model uncertainties, multiplicative faults and additive faults. An observer-based fault detection filter is constructed to generate fault information under deception attack. A randomized algorithm based approach is developed to determine the observer gain and threshold for attaining a trade-off between the false alarm rate (FAR) and fault detection rate (FDR). Simulation of an unmanned surface vehicle (USV) system and comparison against existing work are performed to illustrate the effectiveness of the proposed scheme.

Co-Design of Observer-Based Fault Detection Filter and Dynamic Event-Triggered Controller for Wind Power System Under Dual Alterable DoS Attacks

In this article, a novel co- design approach of observed-based fault detection filter (FDF) and dynamic event-triggered controller is proposed for multi-area wind power system under dual alterable aperiodic (DAA) denial-of-service (DoS) attacks. It is the first attempt to design an observed-based FDF for wind power system considering actuator fault signal. And a tolerable actuator fault threshold function is constructed to warn the occurrence of fault signal. Then, considering the bandwidth limitation of network communication, a novel dynamic event-triggered scheme is proposed to decrease the occupation of communication channel. Furthermore, the DAA DoS attacks presented in this work have different blocking effects on data transmission in different network channel. On account of the existence of aperiodic DoS attacks, the general load frequency control model for wind power system is reconstructed as a new switched system. Based on the reconstructed model, the stability with an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_{\infty }$ </tex-math></inline-formula> performance index is demonstrated by constructing appropriate polynomial Lyapunov-Krasovskii functionals. Besides, the FDF and dynamic event-triggered controller can be achieved by solving linear matrix inequalities. Finally, some contradistinctive case studies are given to illustrate the feasibility and effectiveness of the approaches proposed in this article.

Simultaneous observer-based fault detection and event-triggered consensus control for multi-agent systems

This paper is concerned with the problem of fault detection and consensus control via event-triggered scheme for a class of linear multi-agent systems subject to external disturbances. For the network of multi-agent systems with unknown faults and disturbances, the event-triggered consensus protocol and observer-based fault detection filter are designed simultaneously. Through the model transformation and decomposition, the specific design problem can be transformed into a multi-objective optimization problem by using a mixed H∞/H− method. Based on the Lyapunov-Krasovskii Theory and Projection Lemma, some sufficient conditions, which ensure the decomposed system is not only asymptotically stable, but also satisfies the prescribed optimization performance constraints, are derived in the form of linear matrix inequalities. Finally, two simulation examples are provided to verify the practicality and validity of the theoretical results.

An $H_{i}/H_{\infty }$ Optimization Approach to Event-Triggered Fault Detection for Linear Discrete Time Systems

In this article, a new event-triggered $H_{i}/H_{\infty }$ optimization fault detection (FD) scheme is proposed for linear discrete time systems. A linear discrete time system with varying sampling periods is first presented to describe the dynamics of an event-triggered system. Based on this, an observer-based fault detection filter (FDF) is constructed as an event-triggered residual generator so that the generated residual signal is completely decoupled from the event-triggered transmission error. The design of event-triggered FDF is formulated as a multiobjective optimization problem denoted by $H_{i}/H_{\infty }$ and an optimal solution can be obtained by recursive calculation of Riccati equations. In addition, an event-triggered residual evaluation strategy is also presented. Comparing with the existing event-triggered FD schemes, the major contribution of this article is to decouple the residual signals from the event-triggered transmission errors completely and, consequently, the FD performance can be improved significantly. Moreover, an optimal tradeoff between the robustness of residual to unknown input and the sensitivity of residual to fault is achieved in the sense of $H_{i}/H_{\infty }$ optimization, while the design of FDF and event generator can be carried out independently. To demonstrate the effectiveness of the proposed method, a vehicle lateral dynamic system is used as a simulation example.

Fault Detection Filter and Controller Co-Design for Unmanned Surface Vehicles Under DoS Attacks

This paper addresses the co-design problem of a fault detection filter and controller for a networked-based unmanned surface vehicle (USV) system subject to communication delays, external disturbance, faults, and aperiodic denial-of-service (DoS) jamming attacks. First, an event-triggering communication scheme is proposed to enhance the efficiency of network resource utilization while counteracting the impact of aperiodic DoS attacks on the USV control system performance. Second, an event-based switched USV control system is presented to account for the simultaneous presence of communication delays, disturbance, faults, and DoS jamming attacks. Third, by using the piecewise Lyapunov functional (PLF) approach, criteria for exponential stability analysis and co-design of a desired observer-based fault detection filter and an event-triggered controller are derived and expressed in terms of linear matrix inequalities (LMIs). Finally, the simulation results verify the effectiveness of the proposed co-design method. The results show that this method not only ensures the safe and stable operation of the USV but also reduces the amount of data transmissions.

Fuzzy Fault Detection Filter Design for Nonlinear Distributed Parameter Systems

This paper is devoted to investigating the observer-based fault detection (FD) filters for nonlinear distributed processes described by hyperbolic partial differential equations (PDEs). To this end, the PDE systems are first approximated by the Takagi-Sugeno fuzzy models with spatiotemporal uncertainties. Then, the fuzzy FD filter is developed for the hyperbolic PDE systems to guarantee that the residual signal is robust against process inputs including disturbances. The dynamic threshold is designed to ensure the real-time detection of potential faults. It is worth mentioning that the distributed weighting factors are used to weigh the residual signal such that the overall fault detectability can be optimized.

Fault Detection for Linear Discrete Time-Varying Systems Subject to Random Sensor Delay: A Riccati Equation Approach

This paper mainly studies the fault detection (FD) problem for linear discrete time-varying systems subject to random sensor delay. By assuming that the measurement channel is with Transmission Control Protocol (TCP), an observer-based FD filter (FDF) is provided as a residual generator via embedding the packet indicator into the filter. To construct this FDF, its design issue is formulated into two sub-problems. One is to maximize the $\mathcal {H}_{-}/\mathcal {H}_{\infty }$ or $\mathcal {H}_{\infty }/\mathcal {H}_{\infty }$ FD performance index, which aims to enhance the ratio of fault sensitivity/disturbance attenuation. The other one is to find the filter parameter matrices such that the error between the residual and the fault is minimized in the $\mathcal {H}_{\infty }$ sense. By employing stochastic analysis and introducing some adjoint operator based optimization approaches, analytical solutions to the aforementioned FDF design problem are derived via solving recursive Riccati equations. An illustrative example is given to show the effectiveness of the proposed methodologies.

An Extended &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$H_{i}/H_\infty $ &lt;/tex-math&gt; &lt;/inline-formula&gt; Optimization Approach to Fault Detection of INS/GPS-Integrated System

This paper deals with the problem of robust fault detection (FD) for an integrated system of inertial navigation system and global position system (INS/GPS). Under the assumption of process disturbance and measurement noise being $l_{2}$ -norm bounded, a state-space model with potential additive fault is first introduced to describe the error dynamics of the INS/GPS integrated system. For the purpose of the FD, an observer-based FD filter (FDF) is used as a residual generator and the design of the FDF is formulated so as to find an observer gain matrix and a postfilter in the framework of $H_{i}/H_\infty $ optimization. By utilizing the techniques of innovation analysis and orthogonal projection, a solution to the extended $H_{i}/H_\infty $ -FDF is given in terms of Riccati recursions. Furthermore, a strategy of residual evaluation is also considered, which concerns the selection of an evaluation function and a threshold. Finally, a flight experiment is implemented to show the effectiveness of the proposed method.

Network-Based Fault Detection Filter and Controller Coordinated Design for Unmanned Surface Vehicles in Network Environments

This paper is concerned with the network-based modeling, and observer-based fault detection filter (FDF) and controller coordinated design for an unmanned surface vehicle (USV) in network environments. Network-based models for the USV subject to actuator faults and wave-induced disturbances are established for the first time by introducing an observer-based FDF, and considering network-induced characteristics such as delays and packet dropouts in the sampler-to-control station communication network channel and the control station-to-actuator communication network channel. Based on these models, network-based FDF and controller coordinated design criteria are derived to asymptotically stabilize the residual system. The designed network-based FDF and controller can guarantee the sensitivity of the residual signal to faults and the robustness of the USV to external disturbances. Fault detection performance analysis verifies the effectiveness of the proposed network-based FDF and controller coordinated design scheme for the USV in network environments.

Robust optimal Hi/H∞ fault detection and its applications in a TGSCM control system

This paper aims to deal with the problem of fault detection in a closed-loop mode for a three-axis gyro-stabilized camera mount under the consideration of unknown disturbances. First, the influences of potential actuator and sensor faults are analysed and, based on this, the faults model as well as an equivalent additive fault input are introduced. For the purpose of fault detection, an observer-based fault detection filter is considered to generate the residual. The sensitivity of the residual to fault is evaluated by the non-zero singular values of the transfer function from fault to residual, whereas the robustness to disturbance is represented by the H∞-norm of the transfer function from disturbance to residual. To obtain a maximum sensitivity/robustness ratio criterion, the design of fault detection filter is formulated as an Hi/ H∞ optimization problem and the unified solutions for the optimization criterion are given. For residual evaluation, a window evaluation function is developed and an analysis of threshold selection is given to reduce the conservativeness of fault detection. Finally, experimental results are presented to demonstrate the effectiveness of the proposed method. It is demonstrated that the proposed method can effectively detect the provided fault as soon as possible.

Optimal Actuator Fault Detection for a TGSCM System Based on Disturbance Compensation

This paper focuses on the detection of actuator faults for a three-axis gyro-stabilized camera mount (TGSCM) subject to $L_{2}$ -norm bounded disturbances. First, the influences of the actuator fault are analyzed and, based on this, the system model with the considered fault is given. For the purpose of fault detection (FD), an observer-based fault detection filter (FDF) is applied to generate the residual, and the sensitivity to fault as well as robustness to disturbance is introduced. As a result, the design of FDF can be formulated as an $H_{i}/H_{\infty}$ optimization problem such that a sensitivity/robustness ratio criterion is maximized. To further improve its robustness, simultaneous FD with disturbance estimation and compensation is considered. Finally, experimental results are presented to demonstrate the effectiveness of the proposed method. It is shown that higher performance FD can be achieved by using the FD scheme based on disturbance compensation.

화력발전소 보일러-터빈 제어시스템의 고장검출시스템 설계

This paper deals with a fault detection system design for a boiler-turbine control system of thermal power plant. We described the nonlinear properties of the boiler-turbine dynamics as a T-S fuzzy system with time varying measurable parameters. We design a residual generator using an observer based fault detection filter. In order to identify the faulted output sensor, an approximate inverse system is connected to the outport of the fault detection filter. We demonstrate the efficiency of the suggested design method via computer simulations.

Fault modelling and detection in power generation, transmission and distribution systems

The study discusses a model-based fault diagnosis scheme for detection of faults in power systems. The fault models in power generating units (PGUs) and transmission and distribution networks (T&DN) have been derived in state space form. An observer-based fault detection filter (FDF) has been used to detect these faults. Observer-based FDF is used because of its simplicity, reliability and ease of implementation. A single machine infinite bus power system is considered wherein a synchronous generator is connected to a T&DN through a bus system. Actuator and sensor faults in PGU, and symmetric faults in T&DN have been modelled and simulated in Matlab/Simulink. The simulation results show that a fault, whenever occurs in the aforementioned parts of power systems, is detected using the knowledge of the faults models proposed in this work.

Fault detection filter design for data reconstruction-based continuous-time networked control systems

This paper is concerned with observer-based fault detection filter design for a continuous-time networked control system (NCS) by taking packet dropouts and network-induced delays into account. An observer-based fault detection filter and a reference residual model are introduced to construct a novel model for the continuous-time NCS. To reduce the time for fault detection, a new data reconstruction scheme is proposed and the corresponding closed-loop model is established. Based on the established models, new fault detection filter design criteria are derived to asymptotically stabilize the residual system. The mutually exclusive distribution characteristic of interval time-varying delays is made full use to deal with integral inequalities for products of vectors. The designed fault detection filters can guarantee the sensitivity of the residual signal to faults. Simulation results illustrate the effectiveness of the proposed observer-based fault detection filter design.

Fault detection and optimization for networked control systems with uncertain time-varying delay

The observer-based robust fault detection filter design and optimization for networked control systems (NCSs) with uncertain time-varying delays are addressed. The NCSs with uncertain time-varying delays are modeled as parameter-uncertain systems by the matrix theory. Based on the model, an observer-based residual generator is constructed and the sufficient condition for the existence of the desired fault detection filter is derived in terms of the linear matrix inequality. Furthermore, a time domain optimization approach is proposed to improve the performance of the fault detection system. To prevent the false alarms, a new threshold function is established, and the solution of the optimization problem is given by using the singular value decomposition (SVD) of the matrix. A numerical example is provided to illustrate the effectiveness of the proposed approach.

Closed-loop fault detection for full-envelope flight vehicle with measurement delays

A closed-loop fault detection problem is investigated for the full-envelope flight vehicle with measurement delays, where the flight dynamics are modeled as a switched system with delayed feedback signals. The mode-dependent observer-based fault detection filters and state estimation feedback controllers are derived by considering the delays’ impact on the control system and fault detection system simultaneously. Then, considering updating lags of the controllers/filters’ switching signals which are introduced by the delayed measurement of altitude and Mach number, an asynchronous H∞ analysis method is proposed and the system model is further augmented to be an asynchronously switched time-delay system. Also, the global stability and desired performance of the augmented system are guaranteed by combining the switched delay-dependent Lyapunov–Krasovskii functional method with the average dwell time method (ADT), and the delay-dependent existing conditions for the controllers and fault detection filters are obtained in the form of the linear matrix inequalities (LMIs). Finally, numerical example based on the hypersonic vehicles and highly maneuverable technology (HiMAT) vehicle is given to demonstrate the merits of the proposed method.

Observer-Based Robust Fault Detection Filter Design and Optimization for Networked Control Systems

The problem of robust fault detection filter (FDF) design and optimization is investigated for a class of networked control systems (NCSs) with random delays. The NCSs are modeled as Markovian jump systems (MJSs) by assuming that the random delays obey a Markov chain. Based on the model, an observer-based residual generator is constructed and the corresponding fault detection problem is formulated as anH∞filtering problem by which the error between the residual signal and the fault is made as small as possible. A sufficient condition for the existence of the desired FDF is derived in terms of linear matrix inequalities (LMIs). Furthermore, to improve the performance of the robust fault detection systems, a time domain optimization approach is proposed. The solution of the optimization problem is given in the form of Moore-Penrose inverse of matrix. A numerical example is provided to illustrate the effectiveness and potential of the proposed approach.

Fault detection for discrete systems based on a descriptor system method

In this study, the problem of fault detection for discrete systems is considered. For control inputs, unknown bounded disturbances and sensor faults, an observer-based fault detection filter is designed based on a descriptor system method such that the error dynamic system is convergent, the effect of the disturbances on the residuals satisfies the H ∞ performance index and the effect of the faults on the residuals satisfies the H - performance index. By a Lyapunov functional approach, a sufficient condition for the solvability of the fault detection problem is expressed in terms of linear matrix inequalities. A numerical example shows the effectiveness of the proposed method.

Fault detection for interval type-2 fuzzy systems with sensor nonlinearities

Abstract This paper deals with the fault detection problem for interval type-2 (IT2) fuzzy systems subject to sensor nonlinearities. By using a general observer-based fault detection filter as a residual generator, the fault detection problem is described as a filter design problem. The fault detection filter is designed to guarantee the prescribed H ∞ performance level. A decomposition approach is employed to handle the characteristic of sensor saturation. Using Lyapunov stability theory, a novel type of IT2 fault detection filter is designed to guarantee that the fault detection system is asymptotically stable with an H ∞ performance. In the design procedure, the parameters of the IT2 filter can be solved by the standard software. The IT2 fuzzy model and IT2 fuzzy filter do not require to share the same lower and upper membership functions. A numerical example is given to demonstrate the feasibility and effectiveness of the proposed method.

Robust Fault Detection of Uncertain Time-Delay Markovian Jump Systems with Different System Modes

In this paper, a robust fault detection filter (RFDF)design scheme is presented for uncertain nonlinear Markovian jump systems with mixed delays. By using a observer-based fault detection filter as residual generator, the RFDF design is formulated as an H ∞-filtering problem. Particularly, two different Markov processes are considered for modeling the randomness of system matrix and the state delay; meanwhile, the corresponding two kinds of transition rate matrices are assumed to be incompletely accessible, that is, the one with partially unknown entries and the other with polytopic uncertainties. By using a new convex polyhedron technique, some new sufficient conditions are established in terms of delay-dependent linear matrix inequalities (LMIs) to synthesize the residual generation scheme. Finally, a numerical example is given to illustrate the effectiveness of the proposed techniques.