Voertuigdynamica van vrachtwagens en getrokken materieel
Henk Nijmeijer
Igo Besselink
HTAS Themabijeenkomst
Vehicle Dynamics Control 1 dec. 2008, SKF Nieuwegein
/ Mechanical Engineering PAGE 102/12/2008
Contents
Automotive education at the TU/e
Research in the field of vehicle dynamics
The lateral dynamics of LZV combinations
Concluding remarks
/ Mechanical Engineering PAGE 202/12/2008
University education
Bachelor/Master system
Bachelorgeneric
1
2
3
year
Masterspecialisation (e.g automotive)
4
5
Homologation
HTS degreeTU/e other universitybachelor degree
acceptance
criteria
/ Mechanical Engineering PAGE 302/12/2008
Master phase – automotive specialisation
two possibilities:
1 - master Mechanical Engineering (AES)specialisation Automotive Engineering Science
within faculty of mechanical engineering
-combustion engines Philip de Goey
-automotive materials Marc Geers-powertrains Maarten Steinbuch
-vehicle dynamics Henk Nijmeijer
2 - master Automotive Technology (AT)
interfacultary programme (mechanical engineering, electrical engineering,
chemical technology, mathematics & computer science, technology management , industrial design)
supported financially by HTAS
new!
/ Mechanical Engineering PAGE 402/12/2008
mechanical engineering combustion engines
automotive materials
powertrains
vehicle dynamics
electrical engineering control, energy mgt.electric actuators
chemical technology battery technologyfuels
computer science embedded softwarebus systems
technology management human factors
industrial design user interaction
Master Automotive Technology (AT)
year: 0 0.5 1 1.25 2
graduation project
pra
cti
cal tr
ain
ing
co
re c
ou
rses
ele
cti
ve c
ou
rses
/ Mechanical Engineering PAGE 502/12/2008
Vehicle Dynamics & related courses
Vehicle Dynamics (40 – 65 students)
• vertical dynamics, ride comfort
• lateral dynamics, steering behaviour
• steady-state tyre behaviour
• focus mainly on passenger cars
Advanced Vehicle Dynamics (20 – 40 students)
• suspension kinematics, multi-body modelling
• tyre dynamics and applications
• truck vertical dynamics, (fatigue) loading
• a number of lecturers from DAF trucks
Integrated Automotive Safety (new)
• passive safety, injury biomechanics
• active safety systems, ADAS, cooperative driving
• a number of lecturers from TNO Automotive
/ Mechanical Engineering PAGE 602/12/2008
Vehicle Dynamics research
Emphasis on:
• tyres
• commercial vehicles
• vehicle control
… but it may also include related topics
e.g. multi-link suspension design/optimisation
/ Mechanical Engineering PAGE 702/12/2008
FEM tyre modelling
FEM wheelFEM tyre
Development of a contact model to improve correlation outdoor measurements and FE computations
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Semi-empirical tyre modelling
Continued development of Pacejka tyre models(in cooperation with TNO Automotive and prof. Pacejka)
• Magic Formula extensions to include tyre inflation pressure
• motorcycle tyre modelling (large camber angles)
• model validation, parameter identification, application to full vehicle simulations
/ Mechanical Engineering PAGE 902/12/2008
Control of an over actuated autonomous vehicle
TNO VEHIL high performance moving base robot
some characteristics
• Vehicle mass 480 kg
• Wheel base 1.4 m
• Track width 1.4 m
• Max. speed 50 km/hr
• Max. accel. 10 m/s2
• 0 to 50 km/hr 2.1 s
• Installed power 30 kW
• Battery pack 288 NiMH,D-cells, 350 V, 75 kg
3 motion degrees of freedom8 actuators (4 steering angles, 4 drive/brake torques)overactuated system with a need for control allocation
/ Mechanical Engineering PAGE 1002/12/2008
Variabele geometry active suspension
Improve ride comfort and vehicle attitude for differentdriving conditions, using a variable geometry actuator
• low energy consumption compared to hydraulics (especially for attitude control)
• actuator hardware is build and tested
• controller development-low level: actuator control-high level: comfort, handling, events,…
• full vehicle simulations to evaluate performance
/ Mechanical Engineering PAGE 1102/12/2008
Truck modelling and validation
Create a validated multi-body model for handing and ride
limited complexity, suitable for control system evaluation
• vertical dynamics: discrete obstacles, Belgian blocks
• lateral dynamics: steady state cornering, step steer
• longitudinal dynamics: acceleration, braking
in cooperation with TNO Automotive and DAF Trucks
/ Mechanical Engineering PAGE 1202/12/2008
Dakar rally trucks
Improve the vertical dynamics on big road obstacles
De Rooy: spring/damper optimisation (fast rebound system)
GINAF: independent suspension, semi-active (hydraulic) system
modelling, analysis, optimisation,…
/ Mechanical Engineering PAGE 1302/12/2008
The lateral dynamics
of LZV combinations
LZV: Langere en Zwaardere Vrachtautocombinatie
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Vehicle length/weight limits
Europe:
• tractor semitrailer: 16.5 m
• truck trailer: 18.75 m
• mass: 40 ton (dependent on country)
Australian road trains (53.5 m,132 ton)
US (up to 35 m, 75 ton)
Sweden/Finland (25.25 m, 60 ton)
/ Mechanical Engineering PAGE 1502/12/2008
Advantages of a 25 m, 60 ton vehicle
Economical/environmental:
• reduced fuel consumption compared to separate vehicles (up to 30 %)
• single driver can transport more goods (+50 %)
• less vehicles on the road (small effect on traffic jams)
cost structure road transport (2005): road transport is growing…
Road tax 1.2 %Tires 1.3%
Insurance 3.0%
Interest 2.8%
Rep & Maint. 3.9%
Depreciation 8.3%
Other cost 11.9%
Fuel 16.8%
Driver 50.8%
/ Mechanical Engineering PAGE 1602/12/2008
Disadvantages
safety:
• “interaction” with other traffic (cyclists, pedestrians, cars)
• stability, in particular roll-over
infrastructure:
• damage to bridges/roads?
• adaptations required(e.g. parking spots near highway)
See e.g. Bast report:
Auswirkungen von neuen
Fahrzeugkonzepten auf die
Infrastruktur des
Bundesfernstraßennetzes, 2006
/ Mechanical Engineering PAGE 1702/12/2008
25 meter vehicles in the Netherlands
Since 2002: 25 meter busses in the city of UtrechtIncreased capacity required (25 m bus: 148 persons)
Another example:
APTS phileas
/ Mechanical Engineering PAGE 1802/12/2008
25 meter commercial vehicles
• Since 2004 limited experiments in the Netherlands (±150 vehicles)
• max. vehicle mass 60 ton (instead of 50 ton)in case of a single driven axle: 57.5 ton
• vehicle should be equipped with latest safety devices(e.g. vehicle stability control system, underrun protection, etc.)
• only allowed to drive on designated roads, outside of cities (always permit required, no railway crossings, …)
• driver should have at least 5 years of experience
• …
/ Mechanical Engineering PAGE 1902/12/2008
Possible configurations
max. two turning points:
• backward driving
• lateral stability
max. overall length: 25.25 m
load length limited to:
13.6 + 7.82 = 21.42 m
/ Mechanical Engineering PAGE 2002/12/2008
Some examples…
/ Mechanical Engineering PAGE 2102/12/2008
Evaluate behaviour using a simulation model
general idea:
• to do “virtual” testing
• compare different vehicle combinations – global behaviour
• initial focus: lateral dynamics/stability
vehicle modelling:
• many variants
• generic, not limited to a specific brand/type
• relatively low degree of complexity
simulation tool: MATLAB/Simulink/SimMechanics
/ Mechanical Engineering PAGE 2202/12/2008
Commercial Vehicle Library
TU/e Commercial Vehicle Library
utilities
components
assemblies
vehicles
trailers
steering
throttle
brake
Signals
VR
Mb_trailer
connection
truck_4axles
steering
throttle
brake
Signals
VR
Mb_trailer
connection
truck_3axles
Mb_trailer signals
VRPinCoupling
trailer
steering
throttle
brake
Signals
VR
Mb_trailer
connection
tractor
Mb_trailersignals
VR
5th wheelconnection
semitrailer
signals
VR
Chassis
load
Mb_trailer signals
VRPinCoupling
drawbar_trailer_3axles
Mb_trailersignals
VR
PinCoupling1connection
drawbar_trailer_2axles
Mb_trailersignals
VR
Pin Couplingconnection
dolly
input (0-1)
Mb_f ront
Mb_rear
Mb_trailer
braking system
VRbody CS
VR_sensor
v arinf
VRwheel
Tyre
Mb signals
VRChassis
Trailer_axle
Mb
delta
signals
VR
Chassis LookAheadBar
Steer_axle
time
Vx
steerangle
Steering
Throttle
Brake
Driver
throttle
omega_wheels
signals
VR
MdChassis
Driveline
Mb
Md
signals
VR
Chassis
Drive_axle
pos acc/v el/pos
Differentiator/fil ter
VR
Chassis
Cabin
Mbrake
Mdriv e
omega
axle wheel
Brake/wheel_bearing
plug and play…
/ Mechanical Engineering PAGE 2302/12/2008
Model parameters
• whenever possible the individual parts are legal with the existing regulations (e.g. 3 axle truck: 26 ton)
• fully loaded condition, density 350 kg/m3 (food, vegetables)
• cargo floor height: 1.3 m, C.G. of cargo 1.0 to 1.25 m above floor
Static axle loads LZV D
--------------------------------------
Front axle 73567 N ( 7499 kg)
Rear axle1 90761 N ( 9252 kg)
Rear axle2 90769 N ( 9253 kg)
Dolly axle1 66075 N ( 6735 kg)
Dolly axle2 66228 N ( 6751 kg)
Trailer axle1 67080 N ( 6838 kg)
Trailer axle2 67070 N ( 6837 kg)
Trailer axle3 67060 N ( 6836 kg)
--------------------------------------
total mass 60001 kg
/ Mechanical Engineering PAGE 2402/12/2008
Swept path analysis
Requirement:
• swept path should be less than 8 m for a circle with an outside diameter of 14.5 m.
/ Mechanical Engineering PAGE 2502/12/2008
Results swept path analysis
15 20 25 304
4.5
5
5.5
6
6.5
7
7.5
8
tractor semitrailer A
B
C
D
E
F
G
vehicle length [m]
sw
ept
path
(ty
res c
entr
e)
[m]
/ Mechanical Engineering PAGE 2602/12/2008
Dynamics: single lane change
Based on SAE J2179 test for evaluating the rearward amplification of multi-articulated vehicles
simulation results for 80 km/h (SAE: 88 km/h)
/ Mechanical Engineering PAGE 2702/12/2008
Performance measures
Rearward Amplification (RA)different vehicle units → different lateral accelerations (+ time shifts)
Dynamic Load Transfer Ratio (DLTR)DLTR =0 same vertical force left/right
DLTR = ±1 tyres on one side are lifted from the ground
( )( ))(max
)(max
,
,
ta
taRA
unittowingy
unittrailingy=
∑
∑
=
=
+
−
=n
i
RizLiz
n
i
RizLiz
FF
FF
DLTR
1
,,
1
,,
/ Mechanical Engineering PAGE 2802/12/2008
Example (configuration C)
rearward amplification
RA = = 2.88
0 2 4 6 8 10 12-4
-3
-2
-1
0
1
2
3
t [s]
ay [
m/s
2]
Lateral accelerations of the axles
steer axle
trailer axle 1
trailer axle 2
trailer axle 3
0 2 4 6 8 10 12-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8dynamic load transfer ratio
t [s]
DL
TR
[-]
truck
trailer
dynamic load transfer ratio
DLTR = 0.75
/ Mechanical Engineering PAGE 2902/12/2008
Animations
/ Mechanical Engineering PAGE 3002/12/2008
Results single lane change
0 1 2 3 4 50
0.2
0.4
0.6
0.8
1
tractor semitrailer
A
B
C
D
E
F
G
rearward amplification [-]
dyn
am
ic lo
ad t
ran
sfe
r ra
tio [
-]
/ Mechanical Engineering PAGE 3102/12/2008
The trade-off is obvious…
4.5 5 5.5 6 6.5 7 7.5
0.4
0.5
0.6
0.7
0.8
0.9
1
tractor semitrailer
A
B
C
D
E
F
G
swept path (tyres) [m]
dyn
am
ic lo
ad
tra
nsfe
r ra
tio [
-]
roll over risk
limited
maneuverability
/ Mechanical Engineering PAGE 3202/12/2008
Ongoing research
• discussion with RDW, trailer manufacturers
• include other conventional vehicles
• validation with real LZV combinations
• include braking system and roll-over prevention using ESC (student Martijn Pinxteren)
• improve swept path calculation and include steered trailer axles(student: Jan Loof)
• analyse different loading conditions
• sensitivity analysis
• develop design guidelines
• …
/ Mechanical Engineering PAGE 3302/12/2008
Outlook, future
The TU/e would like to set-up a working group to initiate research
in the field of commercial vehicles as a HTAS programme
possible subjects:
• LZVs
• roll-over prevention
• design loads (incl. fatigue)
• independent suspension
• …
...other questions regarding vehicle dynamics are welcome too!
/ Mechanical Engineering PAGE 3402/12/2008
AdressEindhoven University of Technology
Mechanical Engineering - Dynamics & Control
P.O. Box 513
5600 MB Eindhoven
The Netherlands
Prof. Henk Nijmeijer [email protected] (+31 40 2473203/4817)
Dr.Ir. Igo Besselink [email protected] (+31 40 2472781)
