1 Ir. Valerio CIBRARIO Vertical Business Unit Manager, Automotive Solutions, C&S – LMS Italiana Dr. Ir. Joris DE CUYPER Product Line Manager Virtual.Lab MOTION – LMS International Ir. Marco GUBITOSA Research Engineer – LMS International Suspension analysis through reverse engineering in the vehicle development concept phase Virtual.Lab Motion ↔ Imagine.Lab AMESim 4 copyright LMS International - 2008 Suspension analysis through “reverse engineering” in the vehicle development concept phase [1] Chikofsky, E.J.; J.H. Cross II (January 1990). "Reverse Engineering and Design Recovery: A Taxonomy in IEEE Software". IEEE Computer Society: 13–17. The term "reverse engineering" as applied to software means different things to different people, prompting Chikofsky and Cross to write a paper researching the various uses and defining a taxonomy. From their paper: “Reverse engineering is the process of analyzing a subject system to create representations of the system at a higher level of abstraction”.[1] It can also be seen as: "going backwards through the development cycle".[2] [2] Warden, R. (1992). Software Reuse and Reverse Engineering in Practice. London, England: Chapman & Hall, 283–305.
15
Embed
Suspension analysis through reverse engineering in …...4 9 copyright LMS International - 2008 LMS Imagine.Lab AMESim® Internal Combustion Engine Engine control, Air Path Management,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
Ir. Valerio CIBRARIO Vertical Business Unit Manager, Automotive Solutions, C&S – LMS ItalianaDr. Ir. Joris DE CUYPER Product Line Manager Virtual.Lab MOTION – LMS InternationalIr. Marco GUBITOSA Research Engineer – LMS International
Suspension analysis through reverse engineering in the vehicle development concept phase
Virtual.Lab Motion ↔ Imagine.Lab AMESim
4 copyright LMS International - 2008
Suspension analysis through “reverse engineering” in the vehicle development concept phase
[1] Chikofsky, E.J.; J.H. Cross II (January 1990). "Reverse Engineering and Design Recovery: A Taxonomy in IEEE Software".IEEE Computer Society: 13–17.
The term "reverse engineering" as applied to software means different things to different people, prompting Chikofsky and Cross to write a paper researching the various uses and defining a taxonomy.
From their paper:
“Reverse engineering is the process of analyzing a subject system to create representations of the system at a higher level of abstraction”.[1]
It can also be seen as:
"going backwards through the development cycle".[2]
[2] Warden, R. (1992). Software Reuse and Reverse Engineering in Practice. London, England: Chapman & Hall, 283–305.
2
5 copyright LMS International - 2008
Functional specification
Subsystem specification
ComponentDesign
Design
Functional Validation
ComponentValidation
Functional Synthesis & Global Integration
SpecificationsIn
tegr
atio
n
Valid
atio
n
Functional Design
Subsystem Validation & Integration
The Virtual Development Process
6 copyright LMS International - 2008
Parts and Components Solutions
Vehicle Dynamics SolutionFunctional
specification
Subsystem specification
ComponentDesign
Design
Functional Validation
ComponentValidation
Functional Synthesis & Global Integration
SpecificationsIn
tegr
atio
n
Valid
atio
n
Functional Design
Subsystem Validation & Integration
The Virtual Development Process
3
7 copyright LMS International - 2008
LMS Virtual.Lab Motion®
Suspension MotionSimulation
Full Vehicle MotionSimulation
CDTire 30Single flexible ring modelShort wavelength surfaces,
lateral height profile constant
CDTire 40Multiple flexible ringsSuited for
irregular road surfaces like “Belgian Block” or
cleats with variable height or arbitrary position
CDTire 20Rigid ring modelLong wavelength surfaces
pppp
Rim
p
Rim
p
Rim
p
Rim
p
pppp
Dedicated tire modelthe ‘Comfort-Durability’ tire model
• Scalable modeling for handling, comfort and durability• Customization automation• Integrated controls simulation
8 copyright LMS International - 2008
LMS Imagine.Lab AMESim®
Internal Combustion Engine
Engine control, Air Path Management, Combustion,
Hybrid Vehicle
TransmissionPerformance and losses, Comfort, NVH
Vehicle Systems DynamicsBraking, Steering, Suspension, Vehicle dynamics
EnergyStorage Fuel Cell, Battery
Thermal Management Lubrication, Cooling System,
Air conditioning
Electrical Systems
Electromechanical components, Electrical networks
ICE Related HydraulicsFuel Injection, VVT, VVA, Engine
compression brake
4
9 copyright LMS International - 2008
LMS Imagine.Lab AMESim®
Internal Combustion Engine
Engine control, Air Path Management, Combustion,
Hybrid Vehicle
TransmissionPerformance and losses, Comfort, NVH
Vehicle Systems DynamicsBraking, Steering, Suspension, Vehicle dynamics
EnergyStorage Fuel Cell, Battery
Thermal Management Lubrication, Cooling System,
Air conditioning
Electrical Systems
Electromechanical components, Electrical networks
ICE Related HydraulicsFuel Injection, VVT, VVA, Engine
compression brake
• Global vehicle behaviour with usage of conceptual suspensions• Dedicated library for Vehicle Dynamics able to run Real-Time• Linear analyses and optimization• Parametric functions to modify the shape of the kinematics tables• Suitable for vehicle data management• Fully open for connections with Simulink
10 copyright LMS International - 2008
Fusion of 1D – 3D Simulation
Scalable simulationSupport all stages of design
Vehicle dynamics – Ride& Handling, Comfort, NVHPowertrain/driveline comfort and NVH…
Unique “1D - 3D” simulation for scalable mechanical and mechatronic system simulation
Parameterization of the kinematic curves has been done through a quadratic formulation:
Kinematic curves
Where X =Toe AngleCamber Angle
Castor Angle
Wheel BaseHalf Track
Z is the stroke
Those steps brought out a set of 54 parameters
for Front and Rear 30
25 copyright LMS International - 2008
Objective functions definition
[1] Presentation extracted from:Course of “Advances in Optimal Design of Mechanical Systems”Giampiero Mastinu, Massimiliano GobbiHyderabad – 22/26 March 1999
Steady state yaw rate [1]:
Yaw rate overshoot [1]:
Tβ Factor [1]:Improving readiness & keeping tangential to path orientation
Steadyψ&−1
Steady
SteadyMax
ψψψ
&
&& −
SteadyMaxT βψ ⋅&
Initial Understeer Gradient:Getting as close as possible to the target value
Final Understeer number:To have a progressive steering control and not opposite: If >0 final understeer
Full factorial DOETo identify the most important coefficients to be implemented in the dynamic optimization
Selection of the Factors and Responses
Optimization algorithmGA (Genetic Algorithm)
Note that there is no need to use a Response Surface Model (RSM), thanks to the speed of the simulation in AMESim !
∑
−−
− ⋅=i
CBx
iRFi
i
eAffDampingCoe
2
54 48
27 copyright LMS International - 2008
-15000
-10000
-5000
0
5000
10000
15000
20000
-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
-3.00
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
-150 -100 -50 0 50 100
Toe Original Toe New GA
Steer (toe) Angle
-2.00
-1.50
-1.00
-0.50
0.00
0.50
-150 -100 -50 0 50 100
Camber Original Camber New GA
Camber Angle
-5.00
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
-150 -100 -50 0 50 100
Track Width Track Width New GA
Half Track
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
1.20
-150 -100 -50 0 50 100
Wheelbase Wheelbase New GA
Wheelbase
∑
−−
− ⋅=i
CBx
iRFi
i
eAffDampingCoe
2
Front Damper Curve
Results from GA Optimization - Component characteristics
____ Original
Optimized
13
28 copyright LMS International - 2008
Results from GA Optimization - Dynamic response
~ -1,2 s
Lateral AccYaw Rate
Side slip Rate
Original response
Optimized response
Comparison
29 copyright LMS International - 2008
Final geometrical Optimization in Virtual.Lab MOTION
Sensitivity Analysis
Feeding the model with the target curves a cost function to be minimized must be figured out :
∫−
=e
ii
t
tte
dtet
RMS 21
where e is the error between target and desired actual curves of :
• Camber
• Toe
• Wheelbase
• Half trackhigh effectmedium effectlow effect
upperAf-chassis
upperA-Knuckle
lowerA-Knuckle
tierod-knuckle
upperAf-chassisupperAf-chassis
upperA-KnuckleupperA-Knuckle
lowerA-KnucklelowerA-Knuckle
tierod-knuckletierod-knuckle
14
30 copyright LMS International - 2008
Final geometrical Optimization in Virtual.Lab MOTION
Steer (toe) AngleCamber Angle
Half Track Wheelbase
______
Original AMESimOptimized AMESim = Target VL.MOTIONOptimized VL.Motion
X Y ZlowerAf-chassis
lowerAr-chassis
lowerA-lowerdumper
lowerA-knucle -15.0 15.0 15.0
upperAf-chassis -5.0 17.0
upperAr-chassis
upperA-knukle -6.4 -6.8 -10.3
tierod-knucle -2.7 5.3
wheelcenter 4.2
toe_camber_AxisPoint 0.1
upperdumper-chassis
tierod-rack
Hard Points variations
32 copyright LMS International - 2008
Further investigations
Adding elasto-kinematic contribution
Implementation of flexible parts (subframes, trimmed body, …)
Full Multi-attribute Optimization (Ride-comfort & Handling)
15
33 copyright LMS International - 2008
Conclusions
• A reverse engineering methodology in Concept Stage of new vehicle development has been shown
• Show-case has been applied to kinematics of the front suspension to optimize handling in the ISO step-steer maneuver
• Methodology can be extended to complete front and rear K&C characteristics including flexible parts and full multi-attribute optimization for Ride-comfort & Handling maneuvers
• Integration of LMS Virtual.Lab/Motion® and Imagine.Lab AMESim® offers a unique automated solution for the complete simulation study and optimization in chassis and full vehicle performance domain
Ir. Valerio CIBRARIO Vertical Business Unit Manager, Automotive Solutions, C&S – LMS ItalianaDr. Ir. Joris DE CUYPER Product Line Manager Virtual.Lab MOTION – LMS InternationalIr. Marco GUBITOSA Research Engineer – LMS International