Robust Fault Detection of Networked Control
Systems with Time-varying Delay and Random
Packet Loss Based on Delta Operator
Jianxun Zhou and Duanjin Zhang
School of Information Engineering
Zhengzhou University
Zhengzhou 450001, China
E-mail: djzhang@zzu.edu.cn
Abstract—In this paper, the delta operator is applied to describe
the networked control system with time-varying delay and random
packet loss. A robust fault detection filter based on the observer is
proposed to generate the residual signal, thus making the residual
systems to be asymptotically stable and satisfy the H-infinity
performance in delta domain. The parameters of the designed fault
detection filter are obtained by linear matrix inequalities(LMIs).
The numerical example is provided to verify that the proposed filter
can effectively detect faults.
Keywords—networked control system; delay; packlet loss; fault
detection; delta operator.
I.
I
NTRODUCTION
Ne
tworked control systems (NCSs) are feedback control
systems with closed-loops for real-time shared network, which
have several advantages such as low cost, easy operation and
simpler maintenance[1]-[4]. With the development of wireless
communication technology, the NCSs have been applied to a
wide range of areas as the artificial intelligence, the unmanned
aerial vehicle and the satellite communications. However, due
to the complexity of the network environment, the network
transmission will lead to some problems, for example, time-
delay [5] and packet loss [6]-[7], which could inevitably
degrade performances and lead to lose stability in NCSs. For
these reasons, the study on fault detection of NCSs have
attracted a great deal of attention.
The research of NCSs with packet loss and delay has been
received lots of consideration in recent years, and there is an
increasing interest in robust fault detection. An input delay
approach to fault detection of networked control systems with
network-induced delay and data dropout is investigated in [8].
The fault detection problem of a class of networked control
systems with both multiple communication delays and multiple
missing measurements is studied in [9]. A robust fault
detection filter (RFDF) design problem for networked control
systems is proposed in [10], using the Markovian jump system
with model uncertainty by traditional shift operator. The packet
loss in NCSs is described by Bernoulli in [11]-[12].
Currently, most of the existing studies related to NCSs are
separately involved in continuous-time systems and discrete-
time systems with traditional shift operator, but the traditional
shift operator can not make the discrete system approach to the
corresponding continuous system at the high sampling rate and
even make the crowding poles around the boundary of the
stability circle. The delta operator is a unified formulation of
continuous-time models and discrete-time models, which is a
new discretization method [13] proposed by Middleton and
Goodwin in 1986. The delta operator model can make discrete-
time models approach to the corresponding continuous-time
models and avoid the ill-conditioned problem caused by the
traditional shift operator when the sampling rate is high.
For several years, there have been rich achievements
related to delta operator in NCSs and robust fault detection.
The delta operator Kalman filter approach for the problem of
guaranteed cost control for networked control systems is
studied in [14]. The delta-operator-based discrete-time
disturbance observer for a class of uncertain systems is
proposed in [15] and the problem of robust fault detection for
switched systems with time-varying delay using delta operator
approach is considered in [16]. However, quite few researches
are involved in robust fault detection of networked control
systems with random packet dropout and delay using delta
operator, which is the motivation of this paper.
A method of robust fault detection problem of networked
control systems with time-varying delay and random packet
loss based on delta operator is proposed. The time-varying
delay is transformed into the uncertainty of the parameter, and
the random packet loss is described by Markovian jump
system. An observer-based robust fault detection filter is
presented as a residual generator, which ensures that the
residual systems is asymptotically stable and satisfies the