A novel approach to unknown input filter design for discrete-time linear systems

Charandabi, Behnam Allahverdi; Marquez, Horacio J.

doi:10.1016/j.automatica.2014.07.015

Cited by 33 publications

(24 citation statements)

References 11 publications

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“…State feedback plays a significant role in practical system control and fault diagnosis, but some important system states can not be obtained directly due to the limitations of measurement means, so the study of state observers attracts many scholars. And due to the unavoidable noises and disturbances in the system, the researches of robust observers have become a hot topic [1]- [5], such as high order sliding mode observer [3], unknown input observer [4]. However, the design methods proposed in the above literature require noises or disturbances to meet many restrictive conditions, for example, the observer matching condition, which is very difficult to meet for practical systems.…”

Section: Introductionmentioning

confidence: 99%

Reduced-Order and Full-Order Interval Observers Design for Discrete-Time System

Ren

You

et al. 2020

IEEE Access

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In this paper, the design of reduced-order and full-order interval observers for discrete-time system is investigated. First, the original system is transformed into a descriptor system with the ability to estimate the unknown noise of sensors. Next, a reduced-order interval observer design method for descriptor system is presented. The state matrix of the system is obtained by linear transformation, and a Sylvester equation is constructed to find the appropriate observer gain matrix. Then, an existing design method of full-order interval observer is introduced in this paper. Finally, a simulation example is given to demonstrate that the reduced-order interval observer has more accurate interval estimation results than the full-order interval observer.

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Section: Introductionmentioning

confidence: 99%

Reduced-Order and Full-Order Interval Observers Design for Discrete-Time System

Ren

You

et al. 2020

IEEE Access

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“…However, a complete decoupling of all unknown inputs must satisfy the design condition of UIO [3], [10], which can only be ensured by a limited number of practical systems. Thus, in order to overcome this restriction, different methods were further proposed based on different assumptions on the knowledge of unknown inputs (see [11]- [13]).…”

Section: Introductionmentioning

confidence: 99%

Mixed Active/Passive Robust Fault Detection and Isolation Using Set-Theoretic Unknown Input Observers

Tan

Wang

et al. 2018

IEEE Trans. Automat. Sci. Eng.

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This paper proposes a robust fault detection and isolation (FDI) approach that combines active and passive robust FDI approaches. Standard active FDI approaches obtain robustness by using the unknown input observer (UIO) to decouple unknown inputs from residuals. Differently, standard passive FDI approaches achieve robustness by using the set theory to bound the effect of uncertain factors (disturbances and noises). In this paper, we combine the UIO-based and the set-based approaches to produce a mixed robust FDI, which can mitigate the disadvantages and exert the advantages of the two robust FDI approaches. In order to emphasize the role of set theory, the UIO design based on the set theory is named as the set-theoretic UIO (SUIO). A quadrotor subsystem is used to illustrate the effectiveness of the proposed FDI approach.Note to Practitioners-The proposed SUIO-based approach achieves robustness in FD against disturbances, noises, and modeling uncertainties (e.g., linearization errors) either by decoupling or by bounding their effect on the residuals. Moreover, this approach allows FI by generating a set of structured residuals decoupling the effect of faults. The authors think that this method can be used for processes that operate around equilibrium points. In this case, we can linearize the nonlinear systems into linear systems with bounded unknown inputs and then apply the proposed method. Moreover, an important feature of this method is that it can overcome the design condition of the standard UIO approach, which means that it could be applied to a larger number of applications.Index Terms-Active and passive decoupling, robust fault detection and isolation (FDI), set theory, unknown input observer (UIO).

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“…The problem of designing observers for discrete-time systems with unknown inputs has also been addressed extensively [8], [9], [10], [11], [12], [13]. In [8], a sampling delayed observer is constructed if the system is left-invertible without invariant zeros.…”

Section: Introductionmentioning

confidence: 99%

“…A finite impulse response (FIR) system processes the output measurements to reconstruct the initial state and the subsequent state trajectory, with a possible delay related to the properties of the original system, from which the unknown input is recovered with a further delay of one step. In [12], a H ∞ filter approach was proposed for discrete-time linear system with unknown inputs, in which there are no similarity transformations. The description of the original model is modified to construct a linear filter, from which the original states and the unknown inputs of the system are extracted.…”

Section: Introductionmentioning

confidence: 99%