1. Abstract
This poster is reporting the analysis results
over a wireless-communication-based active
trailer steering (WATS) system, which uses a
wireless communication link to facilitate the
exchange of information among vehicle units of
articulated heavy vehicles (AHVs).
 The proposed system increases the safety of
AHVs by preventing unstable motion modes
of such vehicles.
Extended KF and Channel Model Advantageous of DSRC
Conclusion
In proposing WATS system, failure probability
prediction is desired to prevent the system falling
into instable region. A Fading memory algorithm
has been applied in designing EKF to compute
the static character of states and measurements.
 The following time-update equation is used to
propagate the state-estimate and covariance
from one measurement time to the next:
| , λ
, λ
 The scaling parameter, has zero-mean,
uncorrelated Gaussian and Rayleigh
distribution depends on channel model.
λ
 The state variable, derived from the 3-DOF
tractor-trailer model are, the tractor side-slip
angle β , the tractor yaw rate and the
articulated angle between the tractor and the
trailer ψ.
The wireless communication is modeled in a
multipath environment with LOS, using Rician
distribution.
 A Rician fading channel can be described by
two parameters, ratio between the power in
the direct path and other scatter paths, , and
the total power from both paths, Ω.
 In this design, ratio is a function of
articulated angle. It means that when ψ 0,
reaches its maximum.
DSRC systems are the proper media of
choice for communications-based services on
vehicles. Some of the most important reasons
to adopt DSRC as the main communication
scheme are listed below:
 Being allocated for vehicle safety application.
 Providing a secure wireless interface of
active safety application.
 Supporting high speed, low latency and
short-range communication.
 Supporting both vehicle-to-vehicle (V2V) and
vehicle-to-infrastructure (V2I).
The stability of an AHV with WATS system will be
ensured if the transmitted packets are lost or if
the system is experiencing a delay by:
 Deploying optimal configurations of the IEEE
802.11p standard in terms of modulation,
channel estimation and data-rate.
 Proposing a KF-based estimator to predict the
missed and required vehicle’s state, to
increase the maximum tolerable delay.
The lateral acceleration of the tractor and
trailer vs. time of AHV with ATS control.
Fig. 5- Lateral acceleration of the tractor and trailer vs. time
with SNR = 5dB for: (I) The case of corrupted state-vector for
worst wireless configuration (II) The optimum DSRC
configuration (III) The compensation of EKF.
From the simulation results it can be seen that
tuning the physical layer of DSRC of our
application, could improve the time delay and
detectability of transmitting data. In this
experiment, it has been proved that the optimum
parameters through numerical evaluation are
used 16-QAM for modulation, data rate of
4.5Mbps and channel estimation model of
block-type to reduce delay and packet loss.
Moreover, conducting the simulation by
considering optimum physical layer configuration
and proposed EKF estimator, illustrate
significant enhancement in lateral stability of the
AHV due to the estimator.
Objective
 The appropriate physical layer configuration
of the IEEE 802.11p standards, known as
DSRC, is investigated in terms of channel
model, modulation and bit-rate, to reduce
latency.
 The designed extended-KF is examined for
the optimum communication configuration to
investigate the maximum tolerable delay and
packet-loss proposed by channel model.
Fig. 1- Distributed automotive controller using CAN-bus.
 The designed WATS system performs
efficiently in spite of an acceptable level of
delay and packet-loss by introducing an
adaptive control system based on Kalman
filter (KF).
Experimental Results
 In this research, the performance of a
modeled tractor-trailer is analyzed, based
on data generated by TruckSim.
 The data generated by TruckSim is then fed
into the control system that is implemented
using MATLAB/Simulink.
 The communication system is modeled in
MATLAB/Simulink based on DSRC, to
investigate the effects of different
parameters listed below through numerical
evaluation for SNR of 5dB:
 Modulation: BPSK, QPSK, 16-QAM and
64-QAM.
 Data rate: 3Mbps, 4.5Mbps, 6Mbps,
9Mbps and 12 Mbps.
 Channel estimation: Mean-square-error
(MSE), block-type and comb-type.
Approach
Fig. 2- Data flow in the proposed WATS system.
Fig. 3- Safety, control and service channel in IEEE 802.11p.
Simulation Setup
Fig. 4- Schematic view of modeled DSRC in MATLAB.
(I)
(II)
(III)