Abstract—I
n the electro mechanical brake (EMB) system, an
improvement of the fault-tolerant control, like invalid
protections of sensors and electric systems are the key problems
to the development of electric vehicles. The adaptive
fault-tolerant control in this paper is focus on the descriptor
nonlinear system which contains double time-delays and
parameter uncertainties. In fault detection and estimation,
construct the controlled system model which contains
multi-sensor, double time-delays and parameter uncertainties
based on T-S fuzzy model, then design the observer to realize
fault detection and estimation in real-time. In building the
fault-tolerant control model, the first step is to choose an
appropriate sliding surface, and combine the algorithm of
sliding control with adaptive generic model control. Then apply
the state observer to the designed sliding adaptive generic
model, and build the decision model with dynamic fault
reconfiguration. And the goal of this paper about the adaptive
robust fault-tolerant control for the complex nonlinear
controller system is achieved. Numerical SIMULINK
simulation examples are given to illustrate the application and
the effectiveness of the proposed design method.
Index Terms—Electro mechanical brake, sensors, T-S fuzz
y
model, adaptive fault-tolerant control, sliding model control.
I. I
NTRODUCTION
Sensors are
main tools to percept, detect, and obtain
messages. There are several sensors loaded on the electronic
brake pedal simulators and actuators in EMB on the purpose
of detecting current, speed, pressure, acceleration, and
angular velocity etc. Sometimes, these sensors could occur
relaxing, interval, and abrupt faults. As the braking system is
essential for automotive safety, once the EMB system has
fault, it will cause a major threat to vehicle safety [1], [2].
Faults could be caused by external environments like the
electromagnetic field induced by a loaded high-power motor,
the vehicle vibration, temperature changes, as well as a
lifetime of the electronic components. Once any devices in
EMB system has fault occurs, the braking system will
misunderstand the driver’s braking intention, and cause
serious problem [3], [4]. Thus, make the EMB system which
has satisfy output even as fault occurs is necessary. The
adaptive fault-tolerant technology is an important method to
improve the safety and reliability of the system which is
widely used in numerical control field. Actually, general
Manuscript received April 3, 2014; revised May
28, 2014. This work was
supported by the Jilin University of State Key Laboratory of Automotive
Simulation and Control open fund (20121120) and National Natural Science
Foundation of China (61361003).
The authors are with the Jilin University, Changchun, China. And they
are also with of Yanbian Un
iversity, Yanji, China (e-mail:
ynxu@ybu.edu.cn, kdeng@jlu.edu.cn).
control
led systems show properties like nonlinear,
time-varying, disturbances, and uncertainties, the accurate
mathematical model is difficult to be constructed. Takagi and
Sugeno have mentioned the T-S fuzzy model method which
is used to describe complicated nonlinear system [5]. Then
Taniguchi T. proposed T-S fuzzy descriptor system model in
1999 which can transfer the nonlinear system to multiple
topical linear system, simplified the control process and
improve the control accuracies [6]. In order to solve the
time-delay problem of sensor fault, Gao etc. published the
fault-tolerant control method where the observer is designed
through constructing a linear descriptor system [7]. Most of
previous researches are focused on system model, fault
model, time-delays, and stability analysis based on the given
controlled system (eg. the sensor or the actuator). On the
other hand, there are few researches about multi-target global
nonlinear descriptor system considering multi controlled
objects at the same time.
Usually, designs in the nonlinear adaptive fault-tolerant
systems are based on nonlinear process model and nonlinear
controllers. The Kalman filter is a traditional adaptive model
that shows unsatisfied control effects because of its poor
robustness against model errors [8]. The sliding model
control is an effective control method for nonlinear systems
with advantages like fast responses, good transient
performances, the excellent robust, and the anti-perturbation.
Therefore, it can improve the robustness and reliability of the
controlled system [9], [10].
In this paper, the adaptive fault-tolerant control method
based on T-S fuzzy model for EMB system with multiple
sensor faults is proposed. Then, the adaptive generic model
control (AGMC) is improved by combining sliding model
control (SMC). Finally, the fault-tolerant dynamic decision
architecture is constructed based on SMC-AGMC algorithm.
II. T-S
F
UZZY
D
ESCRIPTOR
S
YSTEM
M
ODEL
Fau
lt d
etection is the basis of the fault-tolerant control. In
fault detection and estimation, the main work is to establish
the fault estimation model. In this section, the first step is to
construct the EMB system model which contains double
time-delays and parameter uncertainties based on T-S fuzzy
model. Then design the observer which can estimate system
states and faults in real-time.
T-S fuzzy descriptor system model is usually described by
a series of fuzzy condition sentences, and each fuzzy model
rules can represent one subsystem. Considering describe the
descriptor system with input delay, state delay, and parameter
uncertainties by T-S fuzzy model. Setting R
i
as the fuzzy
m
o
del rule of the T-S fuzzy descriptor system, then the i-th
Research of Multiple Sensors Adaptive Fault-T
olerant
Control Based on T-S Fuzzy Model for EMB System
Y. N. Xu and W. W. Deng
65
International Journal of Engineering and Technology, Vol. 7, No. 1, February 2015
DOI: 10.7763/IJET.2015.V7.768