ANTI-LOCK BRAKING SYSTEM SIMULATION AND

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ANTI-LOCK BRAKING SYSTEM SIMULATION AND
MODELLING IN ADAMSANTI-LOCK BRAKING SYSTEM SIMULATION AND
MODELLING IN ADAMS
B. Ozdalyan， M. V. Blundell
Centre for Automotive Engineering Research and Technology
School of Engineering， Coventry University， Coventry CVlSFB， England
Abstract
This paper presents the application of the ADAMS
(Automatic Dnamic Analysis of Mechanical &stems)
computer programmes to model and simulate the
performance of an anti-lock braking system (ABS). A
study has been conducted based on a single wheel model
and dynamic simulations have been carried out which
combine a braking algorithm representing the ABS. The
braking models described here embody (FIALA) tyre
model based on tyre tests carried out within the School of
Engineering at Coventry University.
These tests were conducted to explore the relationship
between tyre braking force and wheel slip. Whilst braking
torque is applied to the wheel， slip increases until the
wheel is locked and slipping occurs. The simulation
results represented here demonstrate how a simple ABS
algorithm can be transformed into a vehicle braking model
to prevent wheel locking， when severe braking occurs.
One of the main objectives of this paper is to investigate
the complicated interaction between the tyre and the ABS
system. So designers can use this model to decide which
tyres are more suitable with an ABS system. This is
demonstrated by comparing the ABS algorithm with
models using data for two different tyres and also
investigating the influence of changing road conditions
from dry to wet to ice.
The paper concludes with a discussion of the practical
difficulties involved in developing realistic algorithms to
represent ABS in computer simulation.
Key Words
ABS， ADAMS， Automotive， Braking， Modelling
1.0 Introduction
The ADAMS software [I] is used to study the
behaviour of systems consisting of rigid or flexible parts
undergoing large displacement motions. The main usage
of ADAMS is within the automotive industry where the
software is commonly used to study suspensions or to
study the ride and handling performance of full vehicle
models [2-41. This paper describes the use of the software
to investigate the performance of an anti-lock braking
algorithm on a single wheel model.
The experimental data used in this model was obtained
from tests performed by Coventry University and is based
on the front suspension system of a Peugeot 605. The
suspension system measurements were used to verify the
development of the ADAMS model. An initial simplified
ABS algorithm has been developed based on the work
described in [5].
2.0 Modelling
A quarter vehicle was modelled using a single wheel，
the suspension unit and a body representing the quarter
vehicle mass. A schematic of the quarter vehicle model is
shown in Figure 1. The suspension is modelled as a series
of rigid links connected by joints and rubber bushes. The
force characteristics of the spring， the damper and the
bump stop bush are also included. The suspension system
is connected to a quarter model of the vehicle body， which
has longitudinal and vertical degrees of freedom so that
vehicle can freely move on the X and Z direction via to
translational joints， but does not include pitch.
ill I
Figure 1. Quarter suspension model.
A vertical force acts on the body to represent the
effects of weight transfer during the acceleration and a
longitudinal force compensates for the lack of rear
suspension in this model. These two forces were applied
International Conference on SIMULATIOfl 30 September - 2 October 1998， Conference Publication No.457， 0 IEE， 1998