USE OF VEHICLE DYNAMICS SIMULATION IN A FORMULA STUDENT … · 2016. 10. 20. · STUDENT...
Transcript of USE OF VEHICLE DYNAMICS SIMULATION IN A FORMULA STUDENT … · 2016. 10. 20. · STUDENT...
USE OF VEHICLE DYNAMICS SIMULATION IN
A FORMULA STUDENT TEAM
CONTENT.
1.
2.
3.
INTRODUCTION FORMULASTUDENT
INTRODUCTIONKA-RACEING
SIMULATION MODELS3.
4.
5.
6.
SIMULATION MODELS
CONCEPT DECISIONS
SUSPENSION TUNING
CONTROL SYSTEMVERIFICATION
INTRODUCTION FORMULA STUDENT
• Design competition with an
race car theme
• 11 events in 10 countries
and on 5 continents per
year
• Formula Student teams in
INTRODUCTION FORMULA STUDENT
• Formula Student teams in
over 50 different countries
• Over 70 teams in Germany
• 8 disciplines in an event
– 5 dynamic disciplines
– 3 static disciplines
• Goal is to score 1000 points
INTRODUCTION FORMULA STUDENT
INTRODUCTION KA-RACEING
INTRODUCTION KA-RACEING
7
• Formula Student Team of the Karlsruhe Institute of Technology (KIT)
• Founded in 2006, first car in 2007
• Since 2010 every year one electric and one combustion car
One team, two cars!
INTRODUCTION KA-RACEING
• In 2014:– 55 Students
– 2 cars
– 5 events
KIT14c
INTRODUCTION KA-RACEING
• 199 kg
• Self-developed combustion engine
• Drag Reduction System
• 10“ tires on CFRP rims
• Hybrid Chassis
KIT14e
INTRODUCTION KA-RACEING
• 211 kg
• Self-developed electric engines
• Drag Reduction System
• Monocoque
• 10“ tires on CFRP rims
• „Active Yaw Control“ and „Traction Control“
SIMULATION MODELS
Tire Model
• 2007 – 2013: Magic Formula
– Pro:
• very good for steady-state analysis
• low computing time
SIMULATION MODELS
• low computing time
• available Fitting Software
– Contra:
• over 160 parameters
• often problems with oscillations
• hard to properly fit transient
coefficients
• no road uneveness
• no thermal model
SIMULATION MODELS
Tire Model
• Since 2014: KA-RaceTireWheel Load
Model
1. Order
Model
1. Order
Dynamics
Model
Fz
Camber
Slip Vel.
SlipScale Factor
13
TMEasy Camber Model
Fx Fy
Output
Fx Fy
• Electric Powertrain• Simulink Model of Electric Powertrain containing:
– Engine model with efficiency map
– Battery model with efficiency factors
– Recuperation considered
– Control Systems embedded
SIMULATION MODELS
– Control Systems embedded
SIMULATION MODELS
• Aerodynamics• Aerodynamic coefficients as function of ride height, roll and
pitch angle
• Model for DRS actuation
CONCEPT DECISIONS
• Lap-Time Simulation
• Lap-Time Simulation suitable for basic concept decisions
• Driver handling the car close to its physical limits
• Comparison of lap-times sensitivy of lap-time on different
parameters
CONCEPT DECISIONS
parameters
• Powertrain Concept
• Concepts different in:
– Mass
– Intertia
– Number of driven wheels
CONCEPT DECISIONS
Concept 1 Concept 2 Concept 3
2WD, very
light car
4WD, high
inertia,
medium
weight
4WD, high
weight,
medium
inertia, high
torque
Acceleration 100 % 81 % 78 %– Number of driven wheels
– Center of Gravity
– Engine Power
Acceleration 100 % 81 % 78 %
Skid-Pad 100 % 104 % 106 %
Autocross 100 % 88 % 87 %
Endurance 100 % 88 % 87 %
• Aerodynamics Concept
• Aerodynamics in general
CONCEPT DECISIONS
Without Aero With Aero
Cz - 0,2 % 100 %
Cx 31,3 % 100 %
Lap-Time Skid-Pad 103 % 100 %
Lap-Time Autocross 114,2 % 100 %
• Aerodynamics Concept• DRS Concept
CONCEPT DECISIONS
SUSPENSION TUNING
• Sensitivity Studies with Open-Loop-Maneuvers
– Steady-State Cornering
– Steer-Step
– Sinus-Sweep
– Accelerating
SUSPENSION TUNING
• Parameter Studies to:
– Learn about influences of parameters on vehicle dynamics
– Know which parameter to change
– Save Test Time!
SUSPENSION TUNING
CONTROL SYSTEMS VERIFICATION
• Control Systems on electric since KIT12e
– KIT12e: Traction Control
– KIT13e & KIT14e: Traction Control and Active Yaw Control
CONTROL SYSTEMS VERIFICATION
• Verification of Control Systems in CarMaker:
– Do the Control Systems work?
– How is the interaction?
– Is there any strange behaviour in certain maneuvers?
– Do the Control Systems work in all disciplines?
CONTROL SYSTEMS VERIFICATION
• Validation and Parameter Tuning on track!
Thank you!