Fault detection and isolation using viability theory and interval observers

This paper proposes the use of interval observers and viability theory in fault detection and isolation (FDI). Viability theory develops mathematical and algorithmic methods for investigating the viability constraints characterisation of dynamic evolutions of complex systems under uncertainty. These methods can be used for checking the consistency between observed and predicted behaviour by using simple sets that approximate the exact set of possible behaviour (in the parameter or state space). In this paper, FDI is based on checking for an inconsistency between the measured and predicted behaviours using viability theory concepts and sets. Finally, an example is provided in order to show the usefulness of the proposed approachPeer ReviewedPostprint (author's final draft

Analysis of the behavior of coupled loudspeakers in a MIMO ANC system in an enclosure

In this paper the problem of coupling of acoustic sources in a confined space is treated. By considering the coupling of sources in a rectangular enclosure the set of coupled equations governing the acoustical behavior of enclosure are solved. The resulted model can be used to analyze the behavior of a multi-input multi-output (MIMO) active noise control (ANC) system in real application where coupling of sources can not be neglected. Comparison of results to the case that coupling will be ignored among loudspeakers shows that coupling will effectively change the strength of sources and hence the required voltage signals to drive the loudspeakers. The developed model gives an improved description of the acoustic environment inside the rectangular enclosure, especially in an ANC system when sources are placed in a fraction of wavelength and the interaction among sources will change the radiation impedance of other sources

Reducing the Computational Complexity of an RLS-Based Adaptive Controller in ANVC Applications

In this paper a fast array adaptive IIR filter in active noise and vibration control setup is presented. This fast array implementation is an extended form of the fast array algorithms for FIR filter which is studied in literature before. Since the original algorithm derived for ANVC applications was based on RLS recursion its computational complexity was of order O(n(2)) and it was also vulnerable to round-off and finite precision errors that may occur in real-time implementation of the algorithm. The proposed fast array solution of this algorithm not only reduces its computational complexity to the order of O(n) with the same performance, but also because of its matrix nature it has good numerical stability in real-time applications which is a necessity in active noise and vibration control applications

Modeling of coupling of loudspeakers for ANC system in a confined space

In this paper the problem of coupling of acoustic sources in a confined space in treated. By considering the coupling of sources in a rectangular enclosure the set of coupled equations governing the acoustical behavior of enclosure are solved. The resulted model can be used to analyze the behavior of a multi-input multi-output (MIMO) active noise control (ANC) system in real application where coupling of sources can not be neglected. The developed model is an improved description of the acoustic environment inside the rectangular enclosure, especially in an ANC system when interaction among sources will change the radiation impedance of other sources

RECONFIGURABLE CONTROLLER DESIGN FOR ACTUATOR FAULTS IN A FOUR-TANK SYSTEM BENCHMARK

ABSTRACT The purpose of this work is to design a state feedback controller using Parametric Eigenstructure Assignment (PAE) technique that has the capacity to be reconfigured in the case that partial actuator faults occur. The proposed controller is capable of compensating the gain losses in actuators and maintaining the control performance in faulty situations. Simulations show the performance enhancement in comparison to the non-reconfigurable controller through Integral Absolute Error (IAE) index for different fault scenarios

GA-based optimization of a MIMO ANC system considering coupling of secondary sources in a telephone kiosk

In this paper a multi-input, multi-output (MIMO) active noise control system with the aim of global reduction of broadband noise in a telephone kiosk is addressed. The model selected for this optimization problem is the acoustic environment of an enclosure taking into account the effect of coupling of secondary sources used for control purpose. This optimization involves finding the best locations for loudspeakers and microphones inside the enclosure as well as optimizing the control signals considering secondary source coupling. Previous results show that in order to be able to reduce acoustic noise globally inside the enclosure, the frequency range of 50-300 Hz must be selected for control purpose. The mean of acoustic potential energy of the enclosure, when excited in this frequency range, is adopted as a performance measure. This performance index is penalized with the power of the signal required to excite secondary loudspeakers, in order to avoid placements that may need high voltage power amplifier for a desired performance. To find the solution of this problem, i.e. the global minimum of the performance index, several genetic algorithms are proposed and compared. In order to attain the best achievable performance in reaching the global minimum, the parameters of these genetic algorithms are tuned, and used for optimization purpose. Numerical simulations of the acoustical potential energy as well as the sound pressure at different heights of the kiosk, when active noise control (ANC) system operates, confirm the optimality of the locations proposed by the genetic algorithm. (C) 2008 Elsevier Ltd. All rights reserved

Design of a MIMO neuro-controller for ANC system with loudspeaker nonlinearity in enclosure

In this paper optimization of a nonlinear adaptive multi-channel active noise control system in a rectangular enclosure using neural networks is investigated. The model of enclosure is obtained using modal analysis, and the bandwidth of the control system for global reduction of noise is selected between 50-300Hz. Secondary path in modeled offline using MLP and Levenberg-Marquardt algorithm with sum of sinusoid excitation signal. The simulation results for multi-channel case assuming nonlinear loudspeaker in the secondary path, show the performance of feedforward multilayer perceptron neural networks with FxBP algorithm is acceptable in attenuation of noise and its harmonics in the error microphones

A computationally efficient adaptive IIR solution to active noise and vibration control systems

In spite of special advantages of IIR filters in active noise and vibration control (ANVC) applications, the multimodal error surface and instability problem of adaptive IIR filters has prevented its extensive use. To alleviate these problems, in this paper, a new RLS-based fast array adaptive IIR filters in ANVC applications is proposed. The algorithm is developed with slow adaptation assumption and by transforming the active noise and vibration control problem to an output-error identification problem. By derivation of the fast-array equivalent form both computational complexity and numerical stability of the proposed algorithm are improved. The geometrical illustration of the algorithm, in a simple case, is also given to unify and complete its mathematical formulation. In spite of low computational complexity of the order O(n), simulation results confirm high convergence speed of the proposed algorithm and also its ability to reach the lower minimum mean square error in comparison with commonly used adaptive IIR algorithms in ANVC systems