Design of Full‐Order Observers for Systems with Unknown Inputs by Using the Eigenstructure Assignment

Lungu, Mihai; Lungu, Romulus

doi:10.1002/asjc.889

Cited by 19 publications

(16 citation statements)

References 34 publications

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“…From aircraft dynamics' point of view, these represent unknown inputs; an observer for systems with unknown inputs may estimate these unknown inputs, but, more important, it must estimate the system states with very small errors [4]; therefore, in this paper, the unknown input vector V( ) has been randomly chosen. The decision and the activation functions have been chosen of the following forms: ( ) = ( ), 1 ( ( )) = 0.4(1 − tanh( ( ))), 2 ( ( )) = 1 − 1 ( ( )), where the input has the form = −̂, with the gain matrix determined by using the ALGLX optimal algorithm borrowed from [24]; can be also calculated by means of the pole placement technique or other methods.…”

Section: Numerical Simulation Setupmentioning

confidence: 99%

“…The estimation of the states and unknown inputs (noises, measurement uncertainties, faults of sensors or actuators, etc.) for a physical system is needed in order to conceive a control strategy able to minimize the negative effects of the disturbances [4,5]. There are differences between the observers designed for linear or nonlinear systems, the design process being more difficult in the second case; to overcome this drawback, viable solutions can be the model order reduction [6,7] or the usage of the linearization method to obtain a linear system, because this technique (detailed in [8]) allows the transformation of any nonlinear system into the so-called multiple model-sum of linear models, each of them characterizing the system in a specific operating regime.…”

Section: Introductionmentioning

confidence: 99%

“…The observer designed in this paper (the second ROMO ever obtained) is a mixture of the approaches presented in [4,20,21], improved by a rigorous method to increase its robustness. In [20], the necessary and sufficient conditions are presented for the existence and the design of an unknown input functional observer for linear-time invariant (LTI) multivariable systems, subjected to unknown inputs, the existence of the observer being verified by computing a nullspace of a known matrix and testing some matrices' rank conditions.…”

Section: Introductionmentioning

confidence: 99%

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Design of Reduced‐Order Multiple Observers for Uncertain Systems with Unknown Inputs

Lungu

2018

Complexity

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The paper presents the design of a new reduced-order multiple observer for the estimation of the state associated with TakagiSugeno systems with unknown inputs, this being only the second reduced-order multiple observer ever designed. The design of reduced-order multiple observers which can achieve the finite-time state reconstruction for nonlinear systems described by multiple models is a niche area problem; the author of this paper continuing his work started with the introduction of the reducedorder multiple observer concept. The new multiple observer is a combination of a typical reduced-order observer for linear-time invariant multivariable systems and a full-order multiple observer for Takagi-Sugeno systems. The sufficient stability conditions of the observer are derived via the Lyapunov theory and its robustness is improved by means of a novel and efficient method which cancels the negative effect of the uncertainties appearing in the system. To validate the suggested design algorithm, the steps of the design procedure have been summarized and software implemented for the concrete case of a light aircraft lateral-directional motion.

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Section: Numerical Simulation Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design of Reduced‐Order Multiple Observers for Uncertain Systems with Unknown Inputs

Lungu

2018

Complexity

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“…Unknown-input observers (UIOs) have been the focus of research for several years [1][2][3][4]. This is due to the wide range of applications that already exist for this theory, like fault detection and observer-based control of electromechanical systems that are subjected to measurement noise, uncertainties, and disturbances [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Minimal unknown-input functional observers for multi-input multi-output LTI systems

Mohajerpoor

Asayesh

Nahavandi

2015

Journal of Process Control

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“…This subject has recently been the focus of much research [1][2][3][4]. This subject has recently been the focus of much research [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

A New Algorithm to Design Minimal Multi‐Functional Observers for Linear Systems

Mohajerpoor¹,

Asayesh²,

Nahavandi³

2015

Asian Journal of Control

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Designing minimum possible order (minimal) observers for multi-input multi-output (MIMO) linear systems have always been an interesting subject. In this paper, a new methodology to design minimal multi-functional observers for linear time invariant (LTI) systems is proposed. The approach is applicable, and it also helps in regulating the convergence rate of the observed functions. It is assumed that the system is functional observable or functional detectable, which is less conservative than assuming the observability or detectability of the system. To satisfy the minimality of the observer, a recursive algorithm is provided that increases the order of the observer by appending the minimum required auxiliary functions to the desired functions that are going to be estimated. The algorithm increases the number of functions such that the necessary and sufficient conditions for the existence of a functional observer are satisfied. Moreover, a new methodology to solve the observer design interconnected equations is elaborated. Our new algorithm has advantages with regard to the other available methods in designing minimal order functional observers. Specifically, it is compared with the most common schemes, which are transformation based. Using numerical examples it is shown that under special circumstances, the conventional methods have some drawbacks. The problem partly lies in the lack of sufficient numerical degrees of freedom proposed by the conventional methods. It is shown that our proposed algorithm can resolve this issue. A recursive algorithm is also proposed to summarize the observer design procedure. Several numerical examples and simulation results illustrate the efficacy, superiority and different aspects of the theoretical findings.

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Design of Full‐Order Observers for Systems with Unknown Inputs by Using the Eigenstructure Assignment

Cited by 19 publications

References 34 publications

Design of Reduced‐Order Multiple Observers for Uncertain Systems with Unknown Inputs

Design of Reduced‐Order Multiple Observers for Uncertain Systems with Unknown Inputs

Minimal unknown-input functional observers for multi-input multi-output LTI systems

A New Algorithm to Design Minimal Multi‐Functional Observers for Linear Systems

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