IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 66, NO. 4, APRIL 2019 3139
An Average Dwell-Time Method for
Fault-Tolerant Control of Switched Time-Delay
Systems and Its Application
Ying Jin , Youmin Zhang , Senior Member, IEEE, Yuanwei Jing, and Jun Fu , Senior Member, IEEE
Abstract—This paper presents an average dwell-time
method for fault-tolerant control of a class of uncertain
switched linear time-delay systems and also designs an
algorithm to determine the parameters pertaining to the
dwell-time condition. Compared to the literature results,
this paper features the following: 1) the proposed method
is independent of switching polices if switchings are slow
enough in the average sense; 2) the proposed control
design guarantees exponential stabilization of this class of
time-delay linear systems with actuator faults; and 3) this
method treats all actuators in a unified manner without a
need to identify which are faulty or healthy actuators. The
proposed method is applied to the water pollution control
problem, for the first time, to deal with different ratios of
stream flow rates to effluent flow rates.
Index Terms—Fault-tolerant control, switched systems,
uncertainties.
I. INTRODUCTION
T
IME delay can be seen in various practical applications
such as chemical processes, long-distance transmission
networks, and automotive control. When time delay is present
in a dynamic system, it may deteriorate transient performance or
even lead to instability. When time delay is present in a dynamic
system, it may deteriorate transient performance or even lead
to instability. As an important class of hybrid dynamic systems,
switched time-delay systems (i.e., switched systems involving
time delay) have gained much attention for the control issues
[3]–[6] (and see the references therein). Due to the hybrid nature
of switched systems and the complicated features of the time
Manuscript received December 13, 2017; revised April 19, 2018; ac-
cepted May 28, 2018. Date of publication June 28, 2018; date of current
version November 30, 2018. This work was supported in part by the Na-
tional Natural Science Foundation of China under Grant 61503065, Grant
61573282, Grant 61473063, and Grant 61773108, and in part by the
Fundamental Research Funds for the Central Universities under Grant
N170804004 and Grant N150802001. (Corresponding author: Jun Fu.)
Y. Jin and J. Fu are with the State Key Laboratory of Synthetical
Automation for Process Industries, Northeastern University, Shenyang
110819, China (e-mail: jymontreal@gmail.com; junfu@mail.neu.
edu.cn).
Y. Zhang is with the Department of Mechanical, Industrial and
Aerospace Engineering, Concordia University, Montreal, QC H3H 1G8,
Canada (e-mail: youmin.zhang@concordia.ca).
Y. Jing is with the Department of Information Science and Engi-
neering, Northeastern University, Shenyang 110819, China (e-mail:
ywjjing@mail.neu.edu.cn).
Color versions of one or more of the figures in this paper are available
online at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TIE.2018.2847684
delay [7]–[11], [38] to be explored, studies on switched time-
delay systems are still one of the most important research topics
in control areas. Studies on switched time-delay systems are still
one of the most important research topics in control areas.
Another issue in the highly automated industrial systems is
that maintenance or repairs cannot always be provided immedi-
ately to preserve reliability and safety of the industrial systems.
Thus, the presence of uncertain faults and the possibility of faults
occurrence have to be taken into account in the process of the
system stability analysis and controller design to avoid heavy
economic costs or life-threatening prices caused by faults, e.g.,
see the recent important results [1], [2], [12]–[15], [34], [35],
[39]–[41], [44], [45], which lead fault-tolerant control to obtain
more and more attention [16]–[20]. Panagi and Polycarpou [16]
developed a decentralized fault-tolerant controller for a class of
interconnected nonlinear systems, which include finite subsys-
tems to ensure desired tracking performance and stabilization of
the closed-loop systems. In [16], only bounded fault functions,
which satisfy the so-called matching conditions and bounded
uncertain structures of the interconnected systems have been
considered, it did not explicitly take care of the faulty actua-
tors that directly transmit controller signals into the considered
plant. Wang et al. [17]–[20] presented fault-tolerant controllers
for the nonlinear systems with actuator faults to guarantee re-
liable stability of the systems. Their common feature is that
actuators are decomposed into two parts, one of which is sus-
ceptible to faults, and the other of which is robust to faults, to
compensate for actuator faults effectively. However, in order to
implement the controller designs, the two-part decomposition
has to be known in advance. It is, in general, difficult to obtain
in practice due to uncertain and random feature of faults.
However, there are few results reported on fault-tolerant con-
trol of switched systems and that of switched time-delay systems
[3]–[5], [17], [18], [21], [22]. Wang et al. [4], [17], [21] gave suf-
ficient conditions under which the proposed robust fault-tolerant
controller can control the class of nonlinear switched systems
after decomposing actuators into two groups, in the same man-
ner as in [18], i.e., one group is robust to actuator faults, but the
other is susceptible to the faults. Thus, the proposed methods in
[4], [17], and [21] have the same disadvantages from the fault
modeling and characterization viewpoint. Additionally, s truc-
tural uncertainties of input matrices, which can destabilize the
systems, were not considered for this class of switched systems
in [4], [17], and [21]. I n [22], by combining the safe-parking
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