SICE
Annual
Conference in Fukui. August
4-6,2003
Fukui University, Japan
Implementation
of
Inter-Vehicle Communication
System
for
Vehicle Platoon Experiments
via Testbed
Tae Min
Kim,
Jae
Weon
Choi
School of Mechanical Engineering and Research Institute of Mechanical Technology
Pusan
National University, Pusan 609-735,Korea
{tmkim,choiju}Qpusan.ac.!u
Abstract: This study considers the implementation
issues
of the inter-vehicle communication
system for the vehicle platoon experiments via
a
testbed. The testbed, which consists of three
scale vehicles and one RCS(remote control sbation), is developed
as
a
tool for functions evaluation
between simulation studies and full-sized vehicle researches in the previous study. The cooperative
communication of the vehicle-to-vehicle or the vehicle-to-roadside plays
a
key role for keeping the
relative spacing of vehicles small in a vehicle platoon. Then: the traffic capacity could be increased
greatly. The static platoon control, where the number of vehicles remains constant, is sufficient for
the information
to
he transmitted in the suitably fixed interval, while the dynamic platoon control
such
as
merge or split requires more flexible network architecture for the dynamical coordination
of the communication sequence. In this study, the wireless communication device and the reliable
protocol are implemented
for
the flexible network architecture, using the lowcost, short-range,
IShI
band transceiver and the 6-bit microcontroller.
Keywords: vehicle platoon, wireless communication system, testbed
1.
Introduction
Urban road in most major cities becomes congested
more and more because the demand
of
travel exceeds
highway capacity. The congestion problem causes many
other problems: the waste of time and energy, the traf-
fic accident, the pollution, and
so
on.
ITS
(Intelligent
Tkansportation System)
is
developed actively
as
a
SD
lution of these problems. Especially,
IVHS
(Intelligent
Vehicle and Highway System)
is
the major subject in
ITS. The purpose of
IVHS
is
to improve safety
as
well
as
l,o
increase
a
highvmy capacity through automated
vehicles and automated highways.') In IVHS, a exem-
plary method of efficient vehicle control by grouping in
plat.oons has been proposed in PATH program.') The
vehicle platoon
is
a
group of vehicles traveling together
at
a
high speed with relatively small spacing. Vehicles
in close-formation platoons are dynamically coupled hy
feedback control laws. Depending on the information
available for feedback and depending
on
how such
a11
in-
formation
is
processed in the synthesis of
an
automatic
vehicle following control law, dynamic interactions be-
tween vehicles can cause instability in
a
vehicle string.
The control with the information of the lead vehicle
which
is
the first vehicle in
a
platoon and the preced-
cle. For the static platoon control, where the number of
vehicles remains constant,
it
is sufficient, for the iofor-
mation to he transmitted in the suitably fixed interval
since each vehicle dose not require the frequent update
of the control input. This scheme guarantees that each
vehicle in the platoon has an opport,unity to transmit
its
information every one cycle. For the dynamic pla-
toon control, such
as
merge
or
split, the more flexible
network architecture
is
required. In this case, since the
maneuvering vehicle
for
merge
or
split requires the fre-
quent update of the control input, the more inforniatioo
should be transmitted to the maneuvering vehicle than
others. Therefore, the more opportunity to transmit
the information is given to the lead vehicle and the ma-
neuvering vehicle. In this scheme, the cominunicat.ion
sequence should he coordinated effectively. The coordi-
nation of the communication sequence may be achieved
easily by the RCS(remote control station).
In this study, the wireless communication system,
which can coordinate the communication sequence by
the
RCS-
is
implemented for the vehicle longitudinal
platoon experiments.
2.
System Requirements
ing vehicle can only guarantee the stability in
a
vehicle
strii~g.~)
The information of the preceding vehicle can be
ob-
tained relatively by the range radar. But the informa-
tion of the lead vehicle
is
not available to all vehicles
in a platoon. The wireless communication only enables
all
vehicles to obtain the information of the lead whi-
n&jC
flow
capacities
are
affected directly vehicle pla-
toon control strategies. The effectiveness of a platoon
control strategy can be gauged by the maximum traffic
flow
capacity, the attenuation of spacing errors that
it
can guarantee, and the amount of information that
is
needed
to
implement the strategy in real-time. There
are twn main methods of control that have been studied
3414
PR0001/03/0000-1823
$400
0
2003
SICE
