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Abstract : Vol.38No.4(2003.12)
Special Issure : Modeling, Analysis and Control Methods
for Improving Vehicle Dynamic Behavior
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Review
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| P.1 |
Modeling,
Analysis and Control Methods for Improving Vehicle Dynamic
Behavior (Overview) |
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Toshimichi Takahashi
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So-called vehicle dynamics (or controllability and
stability) refer to the "running, cornering and
stopping" of automobiles, which are the most important
and basic performance of automobiles. Therefore, many
studies have been undertaken from several points of
view all over the world. In this paper, our former studies,
which focused on the analysis and modeling of vehicle
and tire behavior, the vehicle dynamics control and
state estimation, and the analysis of driver-vehicle
system, are briefly summarized. Also, the purpose and
background of these studies are mentioned. Moreover,
a brief introduction to the three technical papers included
in this special issue is presented.
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Research Report
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| P.10 |
Modeling
of Tire Overturning Moment Characteristics and the Analysis
of Their Influence on Vehicle Rollover Behavior |
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Toshimichi Takahashi, Masatoshi Hada
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A newly developed tire model for the Overturning Moment
(OTM) characteristics and the analysis of the influence
of OTM on vehicle rollover behavior are presented. The
new OTM model was developed based on the so-called Magic
Formula tire model. The concept of the new model involves
identifying the difference between the simple model
used previously and actual measurements to the newly
definedfunctions. The new model agrees very well with
the measured data over a wide range of tire vertical
loads, slip angles and camber angles.
The influence of tire OTM on the vehicle rollover
behavior was also investigated by means of a full vehicle
simulation in which a rather large steering angle was
input. The results obtained from the vehicle models
with three different tire models (model without OTM,
simple model, and new model) were compared with experimental
results. It was found that the calculated result obtained
with the new OTM model agreed best with the experiment.
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| P.17 |
Development
of Tire Side Force Model Based on "Magic Formula"
with the Influence of Tire Surface Temperature |
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Masahiko Mizuno
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The results of vehicle performance tests often vary
depending on the season or with differences in the road
surface temperature. It is believed that these changes
can partially be attributed to the effect of tire surface
temperature. The aim of this study is to develop a tire
side force model that incorporates the influence of
tire surface temperature.
The newly developed tire side force model incorporates
a thermodynamic model that allows us to consider changes
in the tire surface temperature and a side force model
that allows for the effects of tire surface temperature.
The tire model parameters were identified using the
results obtained with an indoor test facility.
The surface temperature and the side force values predicted
using this model agreed well with actual measurements,
proving the validity of the developed model.
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| P.23 |
Optimum
Vehicle Dynamics Control Based on Tire Driving and Braking
Force |
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Yoshikazu Hattori
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This paper discusses a method of
controlling the tire force exerted by each wheel of
a vehicle as a means of ensuring steerability and stability.
Conventional vehicle stability
control systems generally rely on feedback of vehicle
states such as the side slip angle and yaw rate to enable
stabilization under a range of vehicle/road surface
combinations. On a low-friction road surface that is
incapable of applying sufficient force, however, it
is unreasonable to expect a system to provide sufficient
control upon the occurrence of undesirable vehicle behavior.
The tire force has a non-linear saturating characteristic,
the value of which varies with the vehicle state and
road surface, making it difficult to determine the force
to be generated by each tire to ensure the desired vehicle
behavior.
This report proposes a method of
distributing the target force and moment of a vehicle
to each tire by considering variations in the tire force
caused by changes in the tire's vertical load, the longitudinal
slip, and so on. As a result, the proposed strategy
achieves seamless behavior between the normal and the
critical limit regions. And, we have confirmed that
excellent levels of steerability and stability can be
achieved, relative to conventional stability control
systems, by simulating a slalom maneuver. Also, this
strategy enables effective vehicle control in the face
of unstable phenomena involving unbalanced lateral forces
arising from changes in the vehicle behavior, such as
closing the throttle during a turn maneuver.
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