Unknown input fractional-order functional observer design for one-side Lipschitz time-delay fractional-order systems

2019 ◽  
Vol 41 (15) ◽  
pp. 4311-4321 ◽  
Author(s):  
Mai Viet Thuan ◽  
Dinh Cong Huong ◽  
Nguyen Huu Sau ◽  
Quan Thai Ha
Keyword(s):  
Time Delay ◽  
Nonlinear Systems ◽  
Fractional Order ◽  
Sufficient Conditions ◽  
Quadratic Function ◽  
Observer Design ◽  
Linear Matrix ◽  
Unknown Input ◽  
Functional Observer ◽  
The One

This paper addresses the problem of unknown input fractional-order functional state observer design for a class of fractional-order time-delay nonlinear systems. The nonlinearities consist of two parts where one part is assumed to satisfy both the one-sided Lipschitz condition and the quadratically inner-bounded condition and the other is not necessary to be Lipschitz and can be regarded as an unknown input, making the wider class of considered nonlinear systems. By taking the advantages of recent results on Caputo fractional derivative of a quadratic function, we derive new sufficient conditions with the form of linear matrix inequalities (LMIs) to guarantee the asymptotic stability of the systems. Four examples are also provided to show the effectiveness and applicability of the proposed method.

Reduced-order observer design with unknown input for fractional order descriptor nonlinear systems

2019 ◽  
Vol 41 (13) ◽  
pp. 3705-3713 ◽  
Author(s):  
Tao Zhan ◽  
Shuping Ma
Keyword(s):  
Fractional Order ◽  
Direct Method ◽  
Sufficient Conditions ◽  
Order Reduction ◽  
Electrical Circuit ◽  
Observer Design ◽  
Unknown Input ◽  
Reduced Order ◽  
The Matrix ◽  
Reduced Order Observer

This paper investigates the observer design issues for the quadratic inner-bounded nonlinear descriptor fractional order systems. Considering the disturbances or inaccessible partial inputs, the order reduction of observer with unknown input is firstly implemented for effectively estimating the system state vectors. Then, for the purpose of the system conservatism reduction, the matrix [Formula: see text] and the matrix generalized inverse technique are applied to design the reduced-order observer, which can deal with unknown input with less restrictions of coefficient matrices. By using fractional order Lyapunov direct method, sufficient conditions can be obtained to ensure the existence of the designed observer. Finally, a fractional order electrical circuit is applied to demonstrate the applicability of the proposed approach.

Modeling and Fuzzy Control for Complex Flexible Nonlinear Systems with Time-Delay

2014 ◽  
Vol 602-605 ◽  
pp. 920-923
Author(s):  
Ji Xiang Chen
Keyword(s):  
Time Delay ◽  
Feedback Control ◽  
Nonlinear Systems ◽  
Discrete Time ◽  
State Feedback ◽  
Sufficient Conditions ◽  
State Feedback Control ◽  
Linear Matrix ◽  
Control Approach ◽  
Fuzzy State

A time-delay discrete-time fuzzy singularly perturbed modeling and fuzzy state feedback control approach are presented for a class of complex flexible nonlinear systems with time-delay. The considered flexible nonlinear system is firstly described by a time-delay standard discrete-time fuzzy singular perturbation model. A fuzzy state feedback control law is secondly design. By using a matrix spectral norm and linear matrix inequalities approach, the sufficient conditions of the controller existence are divided. The provided controller not only can stabilize the resulting closed-loop system but also overcome the effects caused by both time-delay and external disturbances. A simulation example is given to illustrate the effectiveness of the developed result.

An unknown input observer-based decentralized fault detection and isolation for a class of large-scale interconnected nonlinear systems

2017 ◽  
Vol 40 (8) ◽  
pp. 2599-2606 ◽  
Author(s):  
Amir Abbasi ◽  
Javad Poshtan
Keyword(s):  
Nonlinear Systems ◽  
Fault Detection ◽  
Large Scale ◽  
Sufficient Conditions ◽  
Fault Detection And Isolation ◽  
Linear Matrix ◽  
Unknown Input ◽  
Unknown Input Observer ◽  
High Convergence Rate ◽  
Interconnected Nonlinear Systems

In this paper, using a bank of decentralized nonlinear unknown input observers, a novel scheme for actuator fault detection and isolation of a class of large-scale interconnected nonlinear systems is presented. For each of the interconnected subsystems, a local nonlinear unknown input observer is designed without the need to communicate with other agents. Sufficient conditions for the observer existence are derived based on the Lyapunov stability theory. To facilitate the observer design, the achieved conditions are formulated in terms of a set of linear matrix inequalities and optimal gain matrices are obtained. By using both system output and its difference with the estimated output in observer equation, each local observer shows a high convergence rate. Simulation of an automated highway system is used to demonstrate the effectiveness of the proposed methodology.

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