An efficient neural network approach to tracking control of an autonomous
surface vehicle with unknown dynamics
Chang-Zhong Pan
a,b,c
, Xu-Zhi Lai
a,b,
⇑
, Simon X. Yang
c
, Min Wu
a,b
a
School of Information Science and Engineering, Central South University, Changsha, Hunan 410083, China
b
Hunan Engineering Laboratory for Advanced Control and Intelligent Automation, Changsha, Hunan 410083, China
c
Advanced Robotics and Intelligent Systems (ARIS) Laboratory, School of Engineering, University of Guelph, Guelph, Ontario, Canada N1G 2W1
article info
Keywords:
Autonomous surface vehicles
Robots
Unknown dynamics
Tracking control
Neural networks
Lyapunov stability
abstract
This paper proposes an efficient neural network (NN) approach to tracking control of an autonomous sur-
face vehicle (ASV) with completely unknown vehicle dynamics and subject to significant uncertainties.
The proposed NN has a single-layer structure by utilising the vehicle regressor dynamics that expresses
the highly nonlinear dynamics in terms of the known and unknown dynamic parameters. The learning
algorithm of the NN is simple yet computationally efficient. It is derived from Lyapunov stability analysis,
which guarantees that all the error signals in the control system are uniformly ultimately bounded (UUB).
The proposed NN approach can force the ASV to track the desired trajectory with good control perfor-
mance through the on-line learning of the NN without any off-line learning procedures. In addition,
the proposed controller is capable of compensating bounded unknown disturbances. The effectiveness
and efficiency are demonstrated by simulation and comparison studies.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
An autonomous surface vehicle (ASV) is also called an un-
manned surface vessel (USV), which can operate on the surface
of lakes, rivers and oceans. Over the past few years, there has been
renewed interest in the development of ASVs, see Benjamin and
Curcio (2004), Caccia et al. (2007), Desa et al. (2007), Martins,
Almeida, Silva, and Pereira (2006) and Xu, Chudley, and Sutton
(2006) for example. Due to their emerging applications in commer-
cial, civilian and military missions (Størkersen, Kristensen, Indree-
ide, Seim, & Glancy, 1998), the control of ASVs has become an
intensive research area. However, how to control the ASVs effi-
ciently is still very challenging, which might stem from the fact
that (Fossen, 2002): (1) it is hard to use current modelling
techniques to obtain an accurate vehicle dynamic model, which
is generally highly nonlinear, time-varying, and coupled in nature;
and (2) the operation environment of marine vehicles is usually
very complex and unstructured, which brings unpredictable per-
turbations to the control system, such as ocean currents, waves
and wind.
Basic control problems of surface vehicles are classified into
point stabilisation (Liu, Yu, & Zhu, 2011), way-point manoeuvring
(Fredriksen & Pettersen, 2006), path following (Almeida, Silvestre,
& Pascoal, 2007; Bibuli, Bruzzone, & Caccia, 2009), trajectory track-
ing (Zou, Chen, Feng, & Liu, 2011), and formation control (Peng,
Wang, Chen, Hu, & Lan, 2012). Many control approaches have been
proposed in the literature, such as conventional PID control, non-
linear recursive/adaptive control, sliding-mode control (SMC),
and intelligent control. PID control is very simple and easy to
understand. But due to the complexities of the surface vehicles,
the designed controllers (Escario, Jimenez, & Giron-Sierra, 2012;
Fossen, 2002; Moreira, Fossen, & Guedes Soares, 2007) may cause
poor control performance. In addition, the PID tuning is still a
difficult problem, even though there are only three parameters.
To improve the system control performance, nonlinear control-
lers that usually employ Lyapunov method, recursive backstepping
technique, or adaptive control have been widely proposed. For
example, with the aid of Lyapunov’s direct method, Jiang (2002)
designed two systematic tracking controllers for an underactuated
ship. Based on backstepping technique, Du and Guo (2004) estab-
lished an uncertain nonlinear mathematical model and designed
a nonlinear adaptive controller for the course-tracking control.
Aguiar and Hespanha (2007) presented an adaptive switching
supervisory control combined with a nonlinear Lyapunov-based
tracking control law. The controllers using SMC have low sensitiv-
ity to plant parameter variations and disturbances. They can also
greatly improve the system control performance. For instance,
Cheng, Yi, and Zhao (2007) proposed a multi-variable sliding mode
control law for the trajectory tracking of a ship, where the posi-
tions and yaw angle were simultaneously tracked. Ashrafiuon
0957-4174/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.eswa.2012.09.008
⇑
Corresponding author at: School of Information Science and Engineering,
Central South University, Changsha, Hunan 410083, China. Tel./fax: +86 731
88836091.
E-mail address: xuzhi@csu.edu.cn (X.-Z. Lai).
Expert Systems with Applications 40 (2013) 1629–1635
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