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7/27/2019 Vehicle Suspension Model and Dynamic Simulation on Handling Stability
http://slidepdf.com/reader/full/vehicle-suspension-model-and-dynamic-simulation-on-handling-stability 1/5
Vehicle Suspension Model and Dynamic Simulation
on Handling Stability
Xiaobin Ning,Jishen Sheng,Bin MengDepartment of Mechanical Engineering
Zhejiang University of Technology
Hangzhou, China
nxb@zjut.edu.cn
Jie ZhangTechnical Center
Wanxiang Group
Hangzhou, China
aerohoser@263.net
Abstract —Chassis platform is usually supplied for several types
of cars which has their individual requirement for handling
stability and ride comfort. Therefore the stiffness, damping and
the dimension of the guide mechanism of the suspension have to
be adjusted to meet the different performance requirements of
different styles of cars. In this paper a module exclusively for
handling stability analysis of chassis platform is developed basedon ADAMS/Car. With this module chassis engineers can easily
adjust the parameters of suspension such as spring stiffness,
damping and hard points location to match the front and rear
suspension suitably and then predict and optimize the
performance of the suspension system. By this approach different
types of cars that using chassis platform can fulfill their own
handling stability.
Keywords-chassis ; suspension; handing stability;simulation
I. I NTRODUCTION
Chinese vehicle industry are developing quickly at present,and most of them want to take a transition from “develop car
body, borrow foreign mature Chassis” to “develop a chassis platform for cars of different types”, the requirement of chassisassembly system is becoming stronger than any time before
because the level of the platform of shared chassis becomes asymbol of maturity of car manufacturer. In most internationalcar manufacturers, one of their leading techniques is the chassis
platform, with which they can develop different types of carsaccording to the analysis of market through adjusting part of the platform, so they can occupy the market quickly and getmore profit. However since Chinese national car manufacturersare short of related technologies and talented person in car engineering, the design and performance evaluation of theshared chassis have not been developed yet. From a
professional point of view, shared platform refers to the sameset of development techniques which can be applied to cars of different types, so several derived model could bemanufactured from a shared platform. Theoretically it meanscars of different levels could be manufactured from the same
production line to reduce development costs and to increase productivity.
Chassis platform can derive several types of cars and everytype of car has its own requirement of handling stability, so it’snecessary to find a way of simulating and evaluating handlingstability of derived model quickly. An analysis module
exclusively for analysis of suspension kinematic performanceand chassis platform handling stability is developed usingVC++6.0. The module with menus and dialog boxes for theman-machine interface can easily accomplish the modeling,analysis and optimization of suspension and shared chassis,and automatically complete the extraction, management and
display of the data in the analysis process by calling the multi- body dynamic software ADAMS/Car, so the users can greatlyenhance the design efficiency.
II. FUNCTIONS AND MAIN INTERFACE OF THE
MODULE
The module has been developed according to the modeling,simulation, data processing and optimization which arenecessary in the analysis of suspension and shared chassis withVC++6.0 as platform in the windows environment, and it’s
main functions include:Ԙ Automatic parametric subsystem
modeling of the suspension, steering, anti-roll bar, car body
and tires.ԙ
Automatic assembly of the suspension and sharedchassis. Ԛ Easily accomplish the kinematic simulation of
suspension, postprocessor of the simulating results andextraction of the data. So the users can easily evaluate the
kinematic performance of the suspension.ԛEasily analyze and
evaluate the handling stability of shared chassis, automatically
process the simulating results and extract the data. ԜEasily
optimize the suspension and chassis whose kinematic performance and handling stability is not good.
The main interface has been developed with VC++6.0 asshown in Fig 1. The main interface can call every dialog whichwill automatically read the input parameters and open theADAMS/Car to accomplish all the functions introduced above.
This study used a chassis platform from the WanxiangGroup as an example. Firstly the parametric model of front,rear suspension and chassis is built; then the kinematic
performance of the front, rear suspension is analyzed; at lastthe chassis to two types of cars and carried out the simulationof handling stability is applied to verify the practicality of themodule.
978-1-4244-7739-5/10/$26.00 ©2010 IEEE
7/27/2019 Vehicle Suspension Model and Dynamic Simulation on Handling Stability
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Fig.1 Main Interface
III. MODELING AND SIMULATION OF THE
SUSPENSIONS
A. Parametric Modeling of the Macpherson Front
SuspensionsAccording to the requirement of chassis platform, the
suspensions should be parametric models, so the locations of hard points, stiffness of spring, damping of damper and wheelalignment parameters can be easily adjusted to derive severaltypes of cars.
By using the module, the parametric models of themacpherson front suspensions of the two cars were built in themulti-body dynamic software ADAMS/Car and saved to the
private database. Fig.2 shows the assembled model of themacpherson front suspensions of the two cars which includingmacpherson suspension subsystem, front anti-roll bar subsystem and steering subsystem.
Fig.2 Assembled Model of the Front Suspensions of B1, C2
In the module, there are two simulating modes of kinematic performance for the suspensions that built above, parallelwheel travel and opposite wheel travel. This study chose thefirst mode, carried out the "parallel wheel travel±50mm"
simulation of the assembled suspensions by using ADAMS/Car.And results of the simulation are shown in Figures 3, 4 and 5.
Fig.3 Camber Angle Curve of Front Tire
Fig.4 Toe Angle Curve of Front Tire
Fig.5 Lateral Displacement of Front Left Tire
From the results we can see that these parameters (camber, toeand tire lateral displacement) are changing reasonably when thetires travel, so the kinematic performances of the frontmacpherson suspensions of the two cars both reach therequirement of handling stability for the chassis. And thekinematic performance of the front suspension belonged to C2is little better than the front suspension belonged to B1.
B. Parametric Modeling of the Rear Double Link
Suspensions
According to the requirement of chassis, the modeling mode
of rear suspension is just like the front suspension. The parametric model of rear suspensions of B1, C2 have been
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built (shown in the Fig 6) and saved to database by using the
module.
Fig.6 Assembled Model of the Rear Suspensions of B1, C2
Like the front suspension, the "parallel wheel
travel±50mm" simulations were carried out for the rear suspensions of B1, C2. And the results are saved in database.
From the results of the simulation we can see that these
parameters (camber angle, toe angle and tire lateraldisplacement) of the rear suspensions are changing reasonably
when the tires travel, so the kinematic performances of the
double-link rear suspensions of the two cars both reach therequirement of handling stability for the chassis. And the
kinematic performance of the rear suspension belonged to B1
is little better than the rear suspension belonged to C2.
C. Modeling and Simulation of B1 & C2
The chassis platform consists of front macpherson
suspension, rear double-link suspension, tires, car body,
steering system, braking system and power system. In order to
verify the adaptation of chassis to different types of cars, two
cars of different types called B1, C2 are chosen as examples.Their parametric models were built by adjusting the locations
of hard points, stiffness, wheelbase, wheeltrack, full quality
and tires of the chassis. Fig.7 shows the assembled model of
B1, C2 built in ADAMS/Car by using the module. The two
cars have the same type of front, rear suspensions, same FF
engine, same disc brake, and their bodies are simplified to
rigid bodies, their quality are also simplified to centroids
which contain moments of inertia.
Fig.7. Assembled Model of B1, C2
Tableĉ shows the main parameters of B1 and C2.
TABLE I. THE MAIN PARAMETERS OF B1, C2
Main Parameters B1 C2
Full Quality/kg 1579 1845
Front Axle Load/kg 799 849
Rear Axle Load/kg 780 996
Front Wheeltrack/mm 1470 1420
Rear Wheeltrack/mm 1470 1440
Wheelbase/mm 2610 2695
Front SpringStiffness/N·mm-1
24.7 25.1
Rear Spring
Stiffness/N·mm-116.56 16.85
Tires 205/50 R16 185/70 R14
Since steady-state cornering performance is one of the most
important behaviors for handling stability, so it is chose as an
example to test the handling stability of the two cars. The
steps of the steady-state cornering simulation carried out in thestudy refer to the Chinese national standard GB/T 6323.6-
94[7].ķMake the car running along a circle with radius of 15
meters at the lowest stable speed and then fix up the steeringwheel. ĸ Accelerate the car slowly and evenly at a
longitudinal acceleration that less than 0.25m/s2. Ĺ Stop the
simulation when the lateral acceleration reaches to 6.5m/s2.
According to the Chinese national standard, the stead-state
cornering simulations of B1 and C2 were carried out and the
comparative curves of steady-state cornering characters
including 1 2α α − , R/Ro and roll angle of car body are shown
in Figures 8,9 and 10.1 2α α − represents the difference
between later slip angle of front axes and later slip angle of rear axes, R/Ro represents the ratio of cornering radius in one
moment "R" and initial cornering radius "Ro".
Fig. 8 1 2α α − Curve
Fig.9 R/Ro Curve
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Fig.10 Roll Angle Curve
D. Evaluayion
In accordance with the evaluation criteria of steady-state
cornering in Chinese national standard QC/T 480-1999[8],
evaluation of the steady-state cornering characters of the two
cars has been carried out in the study.
Scoring evaluation of the steady-state cornering characters
is based on 3 evaluating indicators: nα (the value of lateral
acceleration at neutral turning point), U (degree of understeer), K ¶(roll-degree of car body). Table 2 shows the values of the 3
indicators of the two cars which can be separately found in
Figures 14 to 16. nα is the value of lateral acceleration in the
1 2α α − curve where the slope is zero; U is the value of
average slope in the 1 2α α − curve where the lateral
acceleration is 2m/s2; K ¶ is the value of average slope in the
roll angle curve where the lateral acceleration is 2m/s2.
TABLE II. VALUES OF THE 3 I NDICATORS OF B1, C2
Indictors B1 C2
2/na m s−⋅ 8.5 8.9
U/ ( ) ( )1
0 2m s−
⋅ ⋅ 0.22 0.27
( ) ( )1
0 2/ K m sφ
−
⋅ ⋅ 0.62 0.7
The scoring equation of n
a can be expressed as:
( )60100 60
40
60an n nn n
N α α α α = + × −−
(1)
Wherean is the scoring value of n
a ; 100na is the upper
limit of na , 100n
a =9.8m/s2; 60na is the lower limit of n
a ,
60na =5.0m/s2.
Calculation of the equation (1): an (B1)=89; an (C2)=92.5.
The scoring equation of U can be expressed as:
( )( )
( )( )60
100 60 100 100
60 40U
U U U U N
U U U U
λ
λ
− −= + ×
− − (2)
Where U is the scoring value of U; 100U is the upper
limit of U,100
U =0.4e/(m•s2);60
U is the lower limit of U,
60
U =1.0e/(m•s2); λ is the coefficient calculated according
to the ratio of 60
U and100
U ,
60 100
100
60 100
2 /
( / ) 24
U U U
U U λ = ×
−=
Calculation of the equation (2):u
(B1)=90;U
(C2)=94.
The scoring equation of K φ can be expressed as:
( )60
60 100
4060 N K K
K K φ φ φ
φ φ
= + × −
−
(3)
Where φ is the scoring value of K φ ;100
K φ is the upper
limit of K φ ,o
100 0.7 K φ = /(m•s2);60
K φ is the lower limit of
K φ ,o
601.2 K φ = /(m•s2).
Calculation of the equation: N φ (B1)=100; φ (C2)=100.
The composite scoring value of B1 and C2 can be derived as:
( ) ( )1 / 3w an U N H N N N φ = + + = (89+90+100)/3=93 (4)
( ) ( )2 / 3w an U
N C N N N φ = + + = (92.5+94+100)/3=95.5 (5)
From the results it can be seen that the composite scoring
values of steady-state cornering characters of the two cars are
both satisfactory, and the steady-state cornering characters of the two cars are both good. Besides, the scoring value of C2 is
slightly higher than B1, so the steady-state cornering character
of C2 is better.
IV. SUMMAR
In this paper, a module exclusively used for analysis of
suspension of chassis platform based on vehicle handling
stability was developed with the platform of VC++6.0 and
ADAMS/Car. By using the module, parameterized models of
the front, rear suspension and the chassis platform were built
in this paper, and kinematic simulations of the front, rear
suspensions were carried out easily and the results show that
the kinematic performance of the suspensions are both goodenough to reach the requirement of handling stability of
chassis platform. Then two cars of different type which using
the chassis were taken as an example to do the cornering
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simulation and evaluation, the results show that the steady-
state cornering characters of the two cars are both good. So
practicality of the module has been verified, and the efficiencyof modeling and analyzing of suspension and chassis platform
is improved with the module.
ACKNOWLEDGMENT
Financial support for this research was provided jointly by
Science and Technology Department of Zhejiang Province
(Grant No.2008C01002) and Zhejiang University of Technology (Grant No.20080174).
R EFERENCES
1 Claudio Gomes Fernandes, Fabio Jum Okano, “Vehicle
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simulating technique in development of suspension and full
vehicle ”, Master Thesis of Jilin University, 2004.
3 LIN Yi, ZHAN Wenzhang, et al. “Dynamics simulation
research on rigid-elastic coupling system of car suspension”,
SAE Paper No.2000-01-1622.
4 Joonhong Park, Dennis A. Guenther, et al. “Kinematic
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simulation”,SAE Paper No.2003-01-0859.
5 ZHAO Youqun, GUO Konghui. “A research on evaluating
indicators of vehicle handling performance”,Vehicle
Engineering, 2001,vol. 23,pp.1-5.
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development”, SAE Paper No.2004-01-1547.
7 “Test method of vehicle handling performance, steady-state
cornering test”, National Standard in People’s Republic of
China, GB/T 6323.6-1994.
8 “Indicator limitation and evaluating method of vehiclehandling performance”, Automotive Standard in People’s
Republic of China, QC/T 480-1999.
9 Using ADAMS/Car, Mechanical Dynamic, Inc, 2002.
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