Adaptive observer design for nonlinear systems using generalized nonlinear observer canonical form

2004 ◽  
Vol 18 (7) ◽  
pp. 1150-1158 ◽  
Author(s):  
Nam-Hoon Jo ◽  
Young-Ik Son
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Tingting Zhang ◽  
Frédéric Kratz ◽  
Yunhui Hou ◽  
Vincent Idasiak

This paper aims to develop a continuous-discrete finite memory observer (CD-FMO) for a class of nonlinear dynamical systems modeled by ordinary differential equations (ODEs) with discrete measurements. The nonlinear systems under consideration are at least locally Lipschitz, which guarantees the existence and uniqueness of solution at each time instant. The proposed nonlinear observer uses a finite number of collected measurements to estimate the system state in the presence of measurement noise. Besides, a one-step prediction algorithm incorporated with an iterative-update scheme is performed to solve the integral problem caused by system nonlinearity, and an analysis of the numerical integration approximation error is given. The properties of estimation performance have been further proved in deterministic case and been analyzed by Monte Carlo simulation in stochastic cases. It is worth noting that the presented method has a finite-time convergence, while most nonlinear observers are usually asymptotically convergent. Another advantage of CD-FMO is that it has no initial value problem. For the application purpose, residuals are generated to implement fault detection cooperated with Cumulative Sum (CUSUM) control charts, while a bank of CD-FMOs is adopted to realize fault isolation for different sensor and actuator faults of the considered nonlinear robotic arm. The robustness and effectiveness of the proposed approach are illustrated via the simulation results.


Automatica ◽  
2018 ◽  
Vol 90 ◽  
pp. 239-247 ◽  
Author(s):  
Mondher Farza ◽  
Mohammed M’Saad ◽  
Tomas Ménard ◽  
Ali Ltaief ◽  
Tarak Maatoug

Author(s):  
Krishnan Srinivasarengan ◽  
José Ragot ◽  
Christophe Aubrun ◽  
Didier Maquin

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.


Author(s):  
Javad Mohammadpour ◽  
Ali Hooshmand ◽  
Heidar Malki ◽  
Karolos Grigoriadis ◽  
Robert Provence

Author(s):  
Mahnoosh Shajiee ◽  
Seyed Kamal Hosseini Sani ◽  
Mohammad Bagher Naghibi-Sistani ◽  
Saeed Shamaghdari

In this paper, a novel method for the design of robust nonlinear observer in the [Formula: see text] framework for Lipschitz nonlinear systems is proposed. For this purpose, a new dynamical structure is introduced that ensures the stability of observer error dynamics. Design innovation is the use of dynamic gain in the sliding mode observer. The additional degree of freedom provided by this dynamic formulation is exploited to deal with the nonlinear term. The performance of this stable [Formula: see text] observer is better than conventional static gain observers and the dynamic Luenberger observer. The compensator is designed in such a way that, while ensuring the stability of the closed-loop system, it prevents performance loss in the presence of the nonlinearities. By the proposed approach, the observer is robust to nonlinear uncertainties because of increasing the Lipschitz constant. Also, the design procedure in the presence of system and measurement noises is addressed. Finally, the simulation of our methodology is conducted on a nonlinear system to illustrate the advantage of this work in comparison with other observers.


1990 ◽  
Vol 15 (4) ◽  
pp. 313-322 ◽  
Author(s):  
Xianchun Ding ◽  
Paul M. Frank ◽  
Limin Guo

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