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Minimax LQG control

Ian Petersen (2006)

International Journal of Applied Mathematics and Computer Science

This paper presents an overview of some recent results concerning the emerging theory of minimax LQG control for uncertain systems with a relative entropy constraint uncertainty description. This is an important new robust control system design methodology providing minimax optimal performance in terms of a quadratic cost functional. The paper first considers some standard uncertainty descriptions to motivate the relative entropy constraint uncertainty description. The minimax LQG problem under...

Model-free reconfiguration mechanism for fault tolerance

Tushar Jain, Joseph J. Yamé, Dominique Sauter (2012)

International Journal of Applied Mathematics and Computer Science

The problem of fault tolerant control is studied from the behavioral point of view. In this mathematical framework, the concept of interconnection among the variables describing the system is a key point. The problem is that the behavior we intend to control is not known. Therefore, we are interested in designing a fault accommodation scheme for an unknown behavior through an appropriate behavioral interconnection. Here we deal simply with the trajectories that are generated by the system in real...

New fault tolerant control strategies for nonlinear Takagi-Sugeno systems

Dalil Ichalal, Benoît Marx, José Ragot, Didier Maquin (2012)

International Journal of Applied Mathematics and Computer Science

New methodologies for Fault Tolerant Control (FTC) are proposed in order to compensate actuator faults in nonlinear systems. These approaches are based on the representation of the nonlinear system by a Takagi-Sugeno model. Two control laws are proposed requiring simultaneous estimation of the system states and of the occurring actuator faults. The first approach concerns the stabilization problem in the presence of actuator faults. In the second, the system state is forced to track a reference...

Non-fragile estimation for discrete-time T-S fuzzy systems with event-triggered protocol

Fei Han, Wei Gao, Hongyu Gao, Qianqian He (2020)

Kybernetika

This paper investigates the non-fragile state estimation problem for a class of discrete-time T-S fuzzy systems with time-delays and multiple missing measurements under event-triggered mechanism. First of all, the plant is subject to the time-varying delays and the stochastic disturbances. Next, a random white sequence, the element of which obeys a general probabilistic distribution defined on [ 0 , 1 ] , is utilized to formulate the occurrence of the missing measurements. Also, an event generator function...

Nonlinear actuator fault estimation observer: An inverse system approach via a T-S fuzzy model

Dezhi Xu, Bin Jiang, Peng Shi (2012)

International Journal of Applied Mathematics and Computer Science

Based on a Takagi-Sugeno (T-S) fuzzy model and an inverse system method, this paper deals with the problem of actuator fault estimation for a class of nonlinear dynamic systems. Two different estimation strategies are developed. Firstly, T-S fuzzy models are used to describe nonlinear dynamic systems with an actuator fault. Then, a robust sliding mode observer is designed based on a T-S fuzzy model, and an inverse system method is used to estimate the actuator fault. Next, the second fault estimation...

Nonlinear model predictive control of a boiler unit: A fault tolerant control study

Krzysztof Patan, Józef Korbicz (2012)

International Journal of Applied Mathematics and Computer Science

This paper deals with a nonlinear model predictive control designed for a boiler unit. The predictive controller is realized by means of a recurrent neural network which acts as a one-step ahead predictor. Then, based on the neural predictor, the control law is derived solving an optimization problem. Fault tolerant properties of the proposed control system are also investigated. A set of eight faulty scenarios is prepared to verify the quality of the fault tolerant control. Based of different faulty...

Notes on μ and l 1 robustness tests

Gábor Z. Kovács, Katalin M. Hangos (1998)

Kybernetika

An upper bound for the complex structured singular value related to a linear time-invariant system over all frequencies is given. It is in the form of the spectral radius of the -norm matrix of SISO input-output channels of the system when uncertainty blocks are SISO. In the case of MIMO uncertainty blocks the upper bound is the -norm of a special non-negative matrix derived from -norms of SISO channels of the system. The upper bound is fit into the inequality relation between the results of...

Novel fault detection criteria based on linear quadratic control performances

Dušan Krokavec, Anna Filasová (2012)

International Journal of Applied Mathematics and Computer Science

This paper proposes a new approach to designing a relatively simple algorithmic fault detection system that is potentially applicable in embedded diagnostic structures. The method blends the LQ control principle with checking and evaluating unavoidable degradation in the sequence of discrete-time LQ control performance index values due to faults in actuators, sensors or system dynamics. Design conditions are derived, and direct computational forms of the algorithms are given. A simulation example...

Observer-based fault-tolerant control against sensor failures for fuzzy systems with time delays

Shaocheng Tong, Gengjiao Yang, Wei Zhang (2011)

International Journal of Applied Mathematics and Computer Science

This paper addresses the problems of robust fault estimation and fault-tolerant control for Takagi-Sugeno (T-S) fuzzy systems with time delays and unknown sensor faults. A fuzzy augmented state and fault observer is designed to achieve the system state and sensor fault estimates simultaneously. Furthermore, based on the information of on-line fault estimates, an observer-based dynamic output feedback fault-tolerant controller is developed to compensate for the effect of faults by stabilizing the...

On improving sensitivity of the Kalman filter

Petr Franěk (2002)

Kybernetika

The impact of additive outliers on a performance of the Kalman filter is discussed and less outlier-sensitive modification of the Kalman filter is proposed. The improved filter is then used to obtain an improved smoothing algorithm and an improved state-space model parameters estimation.

On infinite horizon active fault diagnosis for a class of non-linear non-Gaussian systems

Ivo Punčochář, Miroslav Šimandl (2014)

International Journal of Applied Mathematics and Computer Science

The paper considers the problem of active fault diagnosis for discrete-time stochastic systems over an infinite time horizon. It is assumed that the switching between a fault-free and finitely many faulty conditions can be modelled by a finite-state Markov chain and the continuous dynamics of the observed system can be described for the fault-free and each faulty condition by non-linear non-Gaussian models with a fully observed continuous state. The design of an optimal active fault detector that...

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