scholarly journals Adaptive observer-based fault estimation for a class of Lipschitz nonlinear systems

2016 ◽  
Vol 26 (2) ◽  
pp. 245-259 ◽  
Author(s):  
Nabil Oucief ◽  
Mohamed Tadjine ◽  
Salim Labiod
Keyword(s):  
Nonlinear Systems ◽  
Transfer Functions ◽  
Matching Condition ◽  
Observer Design ◽  
Joint Estimation ◽  
Adaptive Observer ◽  
Fault Estimation ◽  
Linear Matrix ◽  
Lipschitz Nonlinear Systems ◽  
Observer Matching Condition

Abstract Fault input channels represent a major challenge for observer design for fault estimation. Most works in this field assume that faults enter in such a way that the transfer functions between these faults and a number of measured outputs are strictly positive real (SPR), that is, the observer matching condition is satisfied. This paper presents a systematic approach to adaptive observer design for joint estimation of the state and faults when the SPR requirement is not verified. The proposed method deals with a class of Lipschitz nonlinear systems subjected to piecewise constant multiplicative faults. The novelty of the proposed approach is that it uses a rank condition similar to the observer matching condition to construct the adaptation law used to obtain fault estimates. The problem of finding the adaptive observer matrices is formulated as a Linear Matrix Inequality (LMI) optimization problem. The proposed scheme is tested on the nonlinear model of a single link flexible joint robot system.

scholarly journals An adaptive observer design approach for a class of discrete-time nonlinear systems

2018 ◽  
Vol 28 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Krishnan Srinivasarengan ◽  
José Ragot ◽  
Christophe Aubrun ◽  
Didier Maquin
Keyword(s):  
Parameter Estimation ◽  
Nonlinear Systems ◽  
Linear Systems ◽  
Discrete Time ◽  
Design Procedure ◽  
Observer Design ◽  
Joint Estimation ◽  
Adaptive Observer ◽  
Waste Water Treatment Plant ◽  
Joint State

AbstractWe consider the problem of joint estimation of states and some constant parameters for a class of nonlinear discrete-time systems. This class contains systems that could be transformed into a quasi-LPV (linear parameter varying) polytopic model in the Takagi-Sugeno (T-S) form. Such systems could have unmeasured premise variables, a case usually overlooked in the observer design literature. We assert that, for such systems in discrete-time, the current literature lacks design strategies for joint state and parameter estimation. To this end, we adapt the existing literature on continuous-time linear systems for joint state and time-varying parameter estimation. We first develop the discrete-time version of this result for linear systems. A Lyapunov approach is used to illustrate stability, and bounds for the estimation error are obtained via the bounded real lemma. We use this result to achieve our objective for a design procedure for a class of nonlinear systems with constant parameters. This results in less conservative conditions and a simplified design procedure. A basic waste water treatment plant simulation example is discussed to illustrate the design procedure.

LMI Enhanced Observer Design for Lipschitz Nonlinear Systems

2013 ◽  
Vol 756-759 ◽  
pp. 420-424
Author(s):  
Feng Qiao ◽  
Qing Ma ◽  
Feng Zhang ◽  
Hao Ming Zhao
Keyword(s):  
Nonlinear Systems ◽  
Observer Design ◽  
Linear Matrix ◽  
Matrix Inequality ◽  
Simulation Studies ◽  
Complex Issue ◽  
Lipschitz Nonlinear Systems ◽  
Satisfy Lipschitz Condition ◽  
The Relationship ◽  
Selection Of

Observer design for nonlinear systems has been an important and complex issue for decades. In this paper, considering a class of nonlinear systems which satisfy Lipschitz condition, a method for observer design is investigated based on Linear Matrix Inequality (LMI). This study focuses on the selection of gain matrices using LMI for two kinds of Lipschitz nonlinear systems, which are classified by the relationship between output and state. Simulation studies are made with Matlab/Simulink in this paper, and the simulation results verify the effectiveness of the proposed method.

Observer Design for Lipschitz Nonlinear Systems with Output Uncertainty

2014 ◽  
Vol 533 ◽  
pp. 277-280
Author(s):  
Wei Zou ◽  
Yu Sheng Liu ◽  
Kai Liu
Keyword(s):  
Nonlinear Systems ◽  
Asymptotic Stability ◽  
Lyapunov Method ◽  
Observer Design ◽  
Linear Matrix ◽  
Sufficient Condition ◽  
Matrix Inequality ◽  
Output Uncertainty ◽  
Lipschitz Nonlinear Systems ◽  
Simulation Results

This paper presents an observer design for Lipschitz nonlinear systems with output uncertainty. By means of Lyapunov method as well as linear matrix inequality (LMI), the observer gain matrix is determined and a sufficient condition ensuring the asymptotic stability of the observer is proposed. Simulation results demonstrate the robustness of the proposed observer for output uncertainty.

scholarly journals Observer Design for One-Sided Lipschitz Nonlinear Systems Subject to Measurement Delays

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Sohaira Ahmad ◽  
Raafia Majeed ◽  
Keum-Shik Hong ◽  
Muhammad Rehan
Keyword(s):  
Nonlinear System ◽  
Nonlinear Systems ◽  
Time Lag ◽  
Time Derivative ◽  
Observer Design ◽  
Nonlinear Observer ◽  
Linear Matrix ◽  
Lipschitz Nonlinear Systems ◽  
System States ◽  
Lipschitz Systems

This paper presents a novel nonlinear observer-design approach to one-sided Lipschitz nonlinear systems in the presence of output delays. The crux of the approach is to overcome the practical consequences of time delays, encountered due to distant sensor position and time lag in measurement, for estimation of physical and engineering nonlinear system states. A Lyapunov-Krasovskii functional is employed, the time derivative of which is solved using Jensen’s inequality, one-sided Lipschitz condition, and quadratic inner-boundedness, and, accordingly, design conditions for delay-range-dependent nonlinear observer for delayed one-sided Lipschitz systems are derived. Further, novel solutions to the problems of delay-dependent observer synthesis of one-sided Lipschitz models and delay-range-dependent state estimation of linear and Lipschitz nonlinear systems are deduced from the present delay-range-dependent technique. An observer formulation methodology for retrieval of one-sided Lipschitz nonlinear-system states, which is robust againstL2norm-bounded perturbations, is devised. The resultant design conditions, in contrast to the conventional procedures, can be solved via less conservative linear matrix inequality- (LMI-) based routines that succeed by virtue of additional LMI variables, meaningful transformations, and cone complementary linearization algorithm. Numerical examples are worked out to illustrate the effectiveness of the proposed observer-synthesis approach for delayed one-sided Lipschitz systems.

scholarly journals Integrated Fault Estimation and Fault-Tolerant Control for Dynamic Positioning of Ships

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Xiaogong Lin ◽  
Heng Li ◽  
Anzuo Jiang ◽  
Juan Li
Keyword(s):  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Matching Condition ◽  
High Gain ◽  
Iterative Learning ◽  
Fault Estimation ◽  
Linear Matrix ◽  
Dynamic Positioning ◽  
Control Scheme ◽  
Observer Matching Condition

An integrated fault estimation and fault-tolerant control scheme is developed in this paper for dynamic positioning of ships in the presence of an actuator fault. First, an auxiliary derivative output of dynamic positioning ships is constructed in order to satisfy the so-called observer matching condition, and a high-gain observer is designed to exactly estimate the auxiliary derivative outputs. Then, a fault-tolerant controller is developed for dynamic positioning ships based on the iterative learning observer. By means of Lyapunov–Krasovskii stability theory, it is proved that the proposed fault-tolerant controller is able to estimate the total fault effects and states of ships accurately via the iterative learning observer and also to stabilize the closed-loop system. In addition, the parameter design of the proposed fault-tolerant control system can be conveniently solved in terms of linear matrix inequalities. Finally, simulation studies for dynamic positioning ships with actuator faults are carried out, and the results validate the effectivity of the proposed fault-tolerant control scheme.

A new methodology for an adaptive state observer design for a class of nonlinear systems with unknown parameters in unmeasured state dynamics

2016 ◽  
Vol 40 (4) ◽  
pp. 1297-1308 ◽  
Author(s):  
Nabil Oucief ◽  
Mohamed Tadjine ◽  
Salim Labiod
Keyword(s):  
Nonlinear Systems ◽  
Design Procedure ◽  
State Observer ◽  
Observer Design ◽  
Adaptive Observer ◽  
Linear Matrix ◽  
Unknown Parameters ◽  
Structural Requirement ◽  
Persistent Excitation ◽  
Adaptive State Observer

An adaptive state observer is an adaptive observer that does not require the persistent excitation condition to estimate the state. The usual structural requirement for designing this kind of observers is that the unknown parameters explicitly appear in the measured state dynamics. This paper deals with the problem of adaptive state observer synthesis for a class of nonlinear systems with unknown parameters in unmeasured state dynamics. The novelty of the proposed approach is that it requires neither a canonical form nor the approximation of some of the output’s time derivatives. Firstly, we establish a new matrix equality that characterizes the structure of almost all systems found in the very small literature dealing with this problem. Then, this equality is exploited in the construction of the adaptation law. This simplifies the design procedure and makes it very similar to the conventional adaptive state observer design procedure. The problem of finding the observer gains is expressed as a linear matrix inequalities optimization problem. Two examples are given to demonstrate the validity of the proposed scheme.

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.

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