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Published in IET Control Theory and Applications
Received on 5th October 2013
Accepted on 1st August 2014
doi: 10.1049/iet-cta.2014.0362
ISSN 1751-8644
Brief Paper
Global stabilisation of a class of feedforward systems
with distributed delays
Qingrong Liu
1,2
, Zhishan Liang
1
1
College of Geophysics and Information Engineering, China University of Petroleum, Beijing 102249,
People’s Republic of China
2
School of Mathematic and Quantitative Economics, Shandong Uni versity of Finance and Economics,
Jinan 250014, People’s Republic of China
E-mail: liuqingrong18@126.com
Abstract: In this study, both state feedback control and output feedback control design schemes are considered for a class
of feedforward non-linear systems with distributed delays. First, by using the state transformation of non-linear systems, the
problem of designing controller can be converted into that of designing a dynamic parameter, which is dynamically regulated
by a dynamic equation. Then, the dynamic equation is delicately constructed by appraising the non-linear terms of the given
systems. At last, with the help of Lyapunov stability theorem, it is provided the stability analysis for the closed-loop system
consisting of the designed controller and the given systems. A simulation example is given to demonstrate the effectiveness
of the proposed design procedure.
1 Introduction
The asymptotic stabilisation problem of feedforward sys-
tems without delay has been well studied in the area of
triangular structural non-linear systems, see [1, 2] and the
references therein, and most of them designed controller
by the method of forwarding or saturation control. How-
ever, delays often exist in the engineering systems. For
the feedforward non-linear discrete delay systems, some
interesting results have been proposed, see [3–9]. The feed-
forward state-delayed systems were considered in [3–5].
The feedforward input-delayed systems were considered
in [6, 7, 9].
Distributed delay systems are often used to model the time
lag phenomenon in thermodynamics, in population dynam-
ics, in propellant rocket motors as well as in networked
control systems, see [10, 11], so increasing attention has
been devoted to the control design of distributed delay
system. Using predictor-based techniques, exponential sta-
bilisation of linear systems in multi-input systems with
distributed input delays was proved in [10]. Based on the
linear matrix inequality method, the problems of stabilisation
of linear systems with distributed state delays were studied
in [11], the problems of stabilisation of linear systems with
distributed input delays were studied in [12], the problems of
stabilisation and stability of neutral systems with distributed
state delays were investigated in [13, 14].
Although many interesting research results have been
obtained for the linear distributed delay systems (see [10–14]),
and for the non-linear discrete delay systems (see [15] and
the references therein), the problems of robust stability and
robust stabilisation for non-linear distributed delay systems
have not been fully investigated, see [16–18]. Using the
quadratic separation paradigm, the stability of a distributed
delay system with distributed kernel being a polynomial
function was studied in [16]. With the help of the Lyapunov
approach, the state feedback control law for the system
with both discrete and distributed delays was derived in
[17]. Using the reduction model techniques, the problem of
state feedback stabilisation of the non-linear system with
distributed input delay was addressed in [18].
The dynamic gain control approach has been applied
to solve the control design problem of the triangular sys-
tems, see, for example, [3, 4, 19]. However, few works
have exploited this approach to solve the problem of sta-
bilisation for the feedforward non-linear distributed delay
systems. Motivated by the authors [3, 4], in this paper, we
present design schemes of both state and output feedback
stabilisation controllers achieving global asymptotic stabili-
sation of the feedforward non-linear systems with distributed
delays occurring in the input and state variables. In con-
trast to many contributions devoted to the systems with
distributed delay, our control design does not rely on any
linear matrix inequality condition. In contrast to many con-
tributions devoted to the feedforward non-linear systems,
neither saturation nor recursive computation is involved
here, which makes the designed controllers have a simpler
structure.
140 IET Control Theory Appl., 2015, Vol. 9, Iss. 1, pp. 140–146
© The Institution of Engineering and Technology 2014 doi: 10.1049/iet-cta.2014.0362