Short communication
Novel design of adaptive neural network controller for a class
of non-affine nonlinear systems
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Shen Qikun, Zhang Tianping
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College of Information Engineering, Yangzhou University, Yangzhou 225009, PR China
article info
Article history:
Received 4 December 2009
Received in revised form 1 April 2011
Accepted 1 August 2011
Available online 23 August 2011
Keywords:
Non-affine nonlinear systems
Adaptive control
NNs
abstract
The tracking control problem is studied for a class of uncertain non-affine systems. Based
on the principle of sliding mode control (SMC), using the neural networks (NNs) and the
property of the basis function, a novel adaptive design scheme is proposed. A novel Lyapu-
nov function, which depends on both system states and control input variable, is used for
the development of the control law and the adaptive law. The approach overcomes the
drawback in the literature. In addition, the lumped disturbances are taken in account. By
theoretical analysis, it is proved that tracking errors asymptotically converge to zero.
Finally, simulation results demonstrate the effectiveness of the proposed approach.
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
Over the past two decades, stability analysis and stabilization of nonlinear systems have been developed successfully, and
many excellent results have been obtained [1–12]. Speaking in general, according to the systems with or without the actu-
ator nonlinearity, the considered systems can be divided into two parts: the healthy systems and the faulty systems. In [1–3],
variable fuzzy controllers were proposed for the nonlinear healthy systems. For a class of interconnected systems, the prob-
lem of stable fuzzy control was studied, and a design scheme of an adaptive fuzzy controller was proposed under the con-
dition that the control input should be linear [4]. However, actuator nonlinearity, such as dead-zone, nonlinear input, and so
on, is quite common in practice systems and devises. The existence of actuator nonlinearity renders the control problem
much more complex and difficult, and might lead to the controlled systems instability. Designing a controller for the systems
with actuator nonlinearity, the effects of the nonlinearity must be taken into account. To solve the stability problem for
uncertain nonlinear systems with actuator nonlinearity, many researchers have devoted a lot of efforts, and proposed many
control approaches. Tao and Kokotovic [5] compensated the dead-zone by constructing adaptive dead-zone inverse. In [6],
fuzzy sliding mode controller was designed for a class of uncertain time-delayed systems with nonlinear input. Shen et al. [7]
studied the chaos tracking control problem for a class of uncertain time-delay chaotic systems with dead-zone and saturat-
ing input, and proposed a novel adaptive sliding mode controller. For uncertain systems with various input nonlinearity,
many control schemes were given in [8–12]. However, the above-mentioned studies had the condition that the systems
or subsystems should be affine.
In practice, there are many nonlinear systems with non-affine structure, such as biochemical process [13], dynamic model
in pendulum control [14], etc. In [15–17], using the approximation property of the neural networks, different adaptive design
schemes were proposed. However, we know, the approximation property of the neural networks is effective just under the
1007-5704/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.cnsns.2011.08.005
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This work was partially supported by the National Natural Science Foundation of China (Nos. 60904030, 60874045, 61174046) and the Natural Science
Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 10KJB510027).
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Corresponding author.
E-mail address: tpzhang@yzu.edu.cn (T. Zhang).
Commun Nonlinear Sci Numer Simulat 17 (2012) 1107–1116
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Commun Nonlinear Sci Numer Simulat
journal homepage: www.elsevier.com/locate/cnsns