Automatica 51 (2015) 200–209
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Automatica
journal homepage: www.elsevier.com/locate/automatica
Brief paper
Adaptive fault-tolerant stabilization for nonlinear systems with
Markovian jumping actuator failures and stochastic noises
✩
Huijin Fan
a
, Bing Liu
a
, Wei Wang
b,1
, Changyun Wen
c
a
School of Automation, Huazhong University of Science and Technology, Wuhan, Hubei Province, 430074, China
b
Department of Automation, Tsinghua University, Beijing, 100084, China
c
School of Electrical Engineering, Nanyang Technological University, Singapore, 639798, Singapore
a r t i c l e i n f o
Article history:
Received 10 May 2013
Received in revised form
19 June 2014
Accepted 14 September 2014
Available online 17 November 2014
Keywords:
Fault tolerant control
Stochastic nonlinear system
Markovian jumping actuator failures
Adaptive control
Backstepping
a b s t r a c t
In this paper we consider the fault-tolerant stabilization problem for a class of nonlinear systems with
uncertain parameters. Uncertainties caused by Markovian jumping actuator failures and stochastic noises
are also taken into consideration. Different from most existing results, the number of actuator failures
may be infinite and stochastic functions related to multi-Markovian variables have been introduced
to denote the failure scaling factors for the actuators, which is practical, but challenging. Three main
difficulties arise: first is how to establish fundamentals for systems involving multi-Markovian variables
and stochastic noises, including the joint transition probability, the infinitesimal generator, the existence
and uniqueness of the solution and so on; second is how to handle the extra transition rate related
terms appearing in the infinitesimal generator of the Lyapunov function; last is how to cope with the
involved higher order Hessian term in the Itô stochastic differentiation. By proposing a new adaptive fault
tolerant control scheme, the boundedness in probability of all the closed-loop signals has been ensured.
An example of altitude fault-tolerant control for a generic hypersonic air vehicle is presented to show the
effectiveness of the proposed scheme.
© 2014 Elsevier Ltd. All rights reserved.
1. Introduction
Actuator failures can be commonly encountered in practical
systems. They may degrade system performance, render instability
of the closed-loop system, or even worse, lead to catastrophic ac-
cidents. To increase system reliability and security, a bank of fault
tolerant control (FTC) schemes, which compensate for the actua-
tor failures and maintain the performance of the closed-loop sys-
tem, have been proposed for deterministic systems, for instance
in Boskovic, Jackson, Mehra, and Nguyen (2009), Corradini and
Orlando (2007), Jiang (1994) and Zhang, Parisini, and Polycarpou
(2004). Recently, adaptive FTC strategy has received much atten-
tion for its capability to deal with system uncertainties as well as
✩
The work was supported by the National Natural Science Foundation of China
under grants 61174079, 61034006 and 61203068. The material in this paper was
not presented at any conference. This paper was recommended for publication in
revised form by Associate Editor Gang Tao under the direction of Editor Miroslav
Krstic.
E-mail addresses: ehjfan@hust.edu.cn (H. Fan), lbhust621@126.com (B. Liu),
wwang28@tsinghua.edu.cn (W. Wang), ecywen@ntu.edu.sg (C. Wen).
1
Tel.: +86 10 62785845 283; fax: +86 10 62773789.
variations caused by actuator failures simultaneously (Tang, Tao, &
Joshi, 2003, 2007; Tao, Chen, & Joshi, 2002; Tao, Joshi, & Ma, 2001;
Wang & Wen, 2010, 2011). It is noted that most existing studies
using adaptive control approach focus on the case of finite num-
ber of actuator failures, that is, once an actuator fails, it will stay
at the faulty mode during its rest operation. However, in practice,
the failed actuators may recover itself and the actuators may fail
more than once; see for example: the failures caused by the elec-
tromagnetic wave interference from the outer space in spacecraft
control systems, or the intermittent failures occurred in computers
or electronic equipments embedded into the actuators, or the fail-
ures caused by the communication network in a control loop. To be
specific, in the spacecraft system, the control torque is generated
by four reaction wheels (Hu & Xiao, 2013), which are activated by
four respective control loops embedding usually with electronic
parts for a high accuracy purpose. Note that the control loop
is sensitive to electromagnetic wave interference from the outer
space. That is, at some time intervals, the control loops may be par-
tial/total loss of effectiveness due to the appearance of the electro-
magnetic wave interference, and hence actuator failures happen
during these time intervals. While at other time intervals, the elec-
tromagnetic wave interference disappears, then the failed reaction
http://dx.doi.org/10.1016/j.automatica.2014.10.084
0005-1098/© 2014 Elsevier Ltd. All rights reserved.