Observer-based adaptive robust control of nonlinear nonaffine systems with unknown gain sign

Arefi, Mohammad Mehdi; Ramezani, Zahra; Jahed‐Motlagh, Mohammad Reza

doi:10.1007/s11071-014-1573-0

Cited by 21 publications

(30 citation statements)

References 21 publications

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“…Remark 4 Several practical systems satisfy Assumptions 1 and 4 [2,8,11,12,14,22,24,26,31,40,58]. Assumption 2 is not restrictive and is crucial for applying the Razumikhin Lemma in the controller design [1,[3][4][5].…”

Section: Remark 3 Frommentioning

confidence: 99%

“…Assumption 2 is not restrictive and is crucial for applying the Razumikhin Lemma in the controller design [1,[3][4][5]. Assumption 3 is frequently required for global controllability of systems, e.g., see 58]. Unlike [32,41,62], the assumption on the derivative of the time-varying delays (being less than one) is relaxed in this paper.…”

Section: Remark 3 Frommentioning

confidence: 99%

“…Remark 8 Similar to [1,3,4,7,17,20,[56][57][58], the neural network w ÃT nẑ t ð Þ ð Þ employed in this paper for approximating the unknown functions contains a single hidden layer with ' neurons and a single output layer with one neuron. The hidden layer activation function can be a logistic sigmoid function, a hyperbolic tangent function, or a radial basis function.…”

Section: Moreover One Hasmentioning

confidence: 99%

“…In the recent research works [6,9], nonlinear fractional-order systems with affine structures have been also investigated. • Nonaffinity: However, there exist several nonlinear nonaffine systems in practice, such as chemical reactors, biochemical processes, some aircraft and pendulum dynamical models, and so on [1,10,12,19,20,23,25,26,44,50,56,58]. Due to the great efforts devoted by researchers, remarkable adaptive control approaches have been developed for non-affine systems [19,44,50,56].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the knowledge of the sign of the control gain is required in [20,23] to facilitate the design of the adaptive controls for nonlinear non-affine systems. • Unknown control direction: As stated in [2,8,10,11,40,58,62], there are many systems with unknown control direction such as electrical systems, biochemical and biophysical processes, robotics, to name but a few. Various robust adaptive fuzzy sliding mode controllers have been presented for a class of nonlinear fractional-order systems with unknown control direction [6,9,38,52].…”

Section: Introductionmentioning

confidence: 99%

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Observer-based adaptive neural network control for a class of MIMO uncertain nonlinear time-delay non-integer-order systems with asymmetric actuator saturation

Zouari

Boulkroune

Ibeas

et al. 2016

Neural Comput & Applic

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This paper focuses on the adaptive neural output feedback control of a class of uncertain multi-input-multioutput nonlinear time-delay non-integer-order systems with unmeasured states, unknown control direction, and unknown asymmetric saturation actuator. Thus, the mean value theorem and a Gaussian error function-based continuous differentiable model are used in the paper to describe the unknown asymmetric saturation actuator and to get an affine model in which the control input appears in a linear fashion, respectively. The design of the controller follows a number of steps. Firstly, based on the semigroup property of fractional-order derivative, the system is transformed into a normalized fractional-order system by means of a state transformation in order to facilitate the control design. Then, a simple linear state observer is constructed to estimate the unmeasured states of the transformed system. A neural network is incorporated to approximate the unknown nonlinear functions while a Nussbaum function is used to deal with the unknown control direction. In addition, the strictly positive real condition, the Razumikhin Lemma, the frequency-distributed model, and the Lyapunov method are utilized to derive the parameter adaptive laws and to perform the stability proof. The main advantages of this work are that:(1) it can handle systems with constant, time-varying, and distributed time-varying delays, (2) the considered class of systems is relatively large, (3) the number of adjustable parameters is reduced, (4) the tracking errors converge asymptotically to zero and all signals of the closed-loop system are bounded. Finally, some simulation examples are provided to demonstrate the validity and effectiveness of the proposed scheme.

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Section: Remark 3 Frommentioning

confidence: 99%

Section: Remark 3 Frommentioning

confidence: 99%

Section: Moreover One Hasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Observer-based adaptive neural network control for a class of MIMO uncertain nonlinear time-delay non-integer-order systems with asymmetric actuator saturation

Zouari

Boulkroune

Ibeas

et al. 2016

Neural Comput & Applic

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Prescribed performance adaptive fuzzy dynamic surface control of nonaffine time‐varying delayed systems with unknown control directions and dead‐zone input

Tooranjipour

Vatankhah

Arefi

2019

Adaptive Control & Signal

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In this paper, an adaptive prescribed performance control method is presented for a class of uncertain strict feedback nonaffine nonlinear systems with the coupling effect of time-varying delays, dead-zone input, and unknown control directions. Owing to the universal approximation property, fuzzy logic systems are used to approximate the uncertain terms in the system. Since there is no systematic approach to determine the required upper bounds of errors in control systems, the prior selection of control parameters to have a satisfactory performance is somehow impossible. Therefore, the prescribed performance technique as a solution is applied in this study to bring satisfactory performance indices to the system such as overshoot and steady state performance within a predetermined bound. Dynamic surface control strategy is also introduced to the proposed control scheme to address the "explosion of complexity" behavior existing in conventional backstepping methods. To ease the control design, the mean-value theorem is utilized to transform the nonaffine system into the affine one. Moreover, with the help of this theorem, the unknown dead-zone nonlinearity is separated into the linear and nonlinear disturbance-like bounded term. The proposed method relaxes a prior knowledge of control direction by employing Nussbaum-type functions, and the effect of time-varying delays are compensated by constructing the proper Lyapunov-Krasovskii functions. The proposed controller guarantees that all the closed-loop signals are semiglobally uniformly ultimately bounded and the error evolves within the decaying prescribed bounds. In the end, in order to demonstrate the superiority of this method, simulation examples are given. KEYWORDS adaptive fuzzy control, dead-zone nonlinearity, dynamic surface control, nonaffine systems, prescribed performance, time-varying delays 1134

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Improved prescribed performance control for nonaffine pure‐feedback systems with input saturation

Wang

et al. 2019

Intl J Robust & Nonlinear

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Summary This work considers an input and output constraint control problem for pure‐feedback systems with nonaffine functions possibly being in‐differentiable. A locally semibounded and continuous condition for nonaffine functions is presented to guarantee the controllability, and the nonaffine system is transformed to an equivalent pseudoaffine one based on the mild condition. Combined with backstepping technique, a novel prescribed performance controller with new performance functions is constructed to circumvent high frequency chattering in control input. An auxiliary system with bounded compensation term is utilized in this paper, successfully avoiding the overrun of control input. The methodology achieves the desired transient and steady‐state performance and presents excellent robustness against the system uncertainty. Finally, two numerical simulations are performed to demonstrate the effectiveness of the proposed approach.

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Observer-based adaptive robust control of nonlinear nonaffine systems with unknown gain sign

Cited by 21 publications

References 21 publications

Observer-based adaptive neural network control for a class of MIMO uncertain nonlinear time-delay non-integer-order systems with asymmetric actuator saturation

Observer-based adaptive neural network control for a class of MIMO uncertain nonlinear time-delay non-integer-order systems with asymmetric actuator saturation

Prescribed performance adaptive fuzzy dynamic surface control of nonaffine time‐varying delayed systems with unknown control directions and dead‐zone input

Improved prescribed performance control for nonaffine pure‐feedback systems with input saturation

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