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BMW Driver Assistance Systems &Active Safety Systems
Karl-Heinz KustermannEngineering Division (China)
China International Automotive Congress 20082008, Oct. 30th – Nov. 1stShenyang, China
Dr. Heinz Leffler, Dr. Joachim Steinle Vehicle Dynamics Development
Driver Assistance Systems & Active Safety Content
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 2
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 3
Driver Assistance SystemsLevel of Safety and Comfort Functions
DPC
DXC
DSCACC
ACC S&G
LDW
PMA
LDW
NiVi
Coll.-Mit.WarningColl.-Mit.
Braking
RFT
Airbags
ACN
Safetybelt-Systems
AFS
Environment: weather, traffic guidance, traffic density
Driver: condition, perception, operation
Vehicle: handling characteristics
Active Safety
(Collision Avoidance)
Passive Safety
(Collision Mitigation)
Vehicle Guidance
active
passive
ComfortSafety
Driver Instruction/-Information/-Warning
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 4
Chassis Control and Driver Assistance SystemsEnhancement of Driver and Car
Deceleration
Steer-ability Agility
VehicleStability
VehicleTraction
Acceleration
Physical LimitVehicleEnhancement
Vehicle PotentialDriverEnhancement
VehicleGuidance
Driver Potential
Chassis Design. Vehicle Genes.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 5
Additional importantparameters
- Drivetrain Concept- Engine Characteristic- Axle Kinemtics/Steering
Wheelbase
FZ V FZ H
Axle LoadDistribution
y
x
x Moment of Inertia Jz
Heightof CG
Track
z
y
= Centre of Gravity (CG)
z Cz,hCz,vAerodyn. Lift
- Seat- MMI
- Weight- Unsprung Masses- Body Stiffness
Aerodynamic
Driver Assistance Systems & Active SafetyDriver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 6
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
Stability Control: xDriveInnovative Transfer Gear Box
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 7
Quelle: Fa. Robert Bosch
EBMx DXC
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 8
Stability Control: xDrivexDrive Drive Train Concept
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 9
FL
FS FS
FL
Fmax
10
2
FL0
FS0
FL2
FS2
FL1
FS1FS1
FL1
Forces at the Wheel:Kamm‘s Circle.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 10
Oversteer
Situation Oversteer:Torque Distribution Front-Rear
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 11
Understeer
Situation Understeer:Torque Distribution Front-Rear
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 12
Handling Course with Low-Friction (Snow track)
-80 -60 -40 -20 0 20 40 60 80 -80 -60 -40 -20 0 20 40 60 80
500
300
100
0
-100
-300
-500
Steering Angle Steering Angle
Permanent 4WDVehicle Stability Control System
not active
xDrive aktiveVehicle Stability Control System
not active
DriftAngle
Grad [°] Grad [°]
Stability Control: xDriveReduced Steering Effort
DriftAngle
xDrive vs. 4WD-DSC:Comparison System Dynamics
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 13
xDrive
TorqueFront Axle = 38 %
t = ca. 0,1 s t = ca. 0,5 s
4x4 with Brake Actuation
xDrive
100 %
DSC 4x4 BA
38 %62 %
Torque Front Axle = 100 %
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 14
Vehicle Stability Control and All-Wheel Drive:BMW Application Philosophy
Per
form
ance
DSC Actuation Threshold
Lateral Dynamics
DSC
Engine ControlBrake Control
Per
form
ance
DSC ActuationThreshold
xDrive + DSC in 3 Series Coupé
Lateral Dynamics
Engine ControlBrake Control
xDrive Control
Driver Assistance Systems & Active SafetyDriver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 15
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
Torque Vectoring:BMW Dynamic Performance Control.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 16
Planetary gear(3 planetary gears)
Multi-discbrake
Ball ramp(Two-stage pitch)
Asynchronousmotor
Separation of oilchambers
Breather
BMW Dynamic Performance Control.Layout of Final Drive Unit.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 17
Multi-discbrake
Planetarygear
Torquevectoring
unit“left”
Torquevectoring
unit“right”
Basic gearbox
BMW Dynamic Performance Control.Torque Flow (I).
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 18
WITHOUT torque transferMleft = Mright
1000 Nm1000 Nm
2000
BMW Dynamic Performance Control.Torque Flow (II).
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 19
WITH torque transferWITH drive torqueMleft < Mright
1400 Nm500 Nm
2000
500 500
1000
100900
BMW Dynamic Performance Control.Torque Flow without Engine Torque.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 20
WITH torque transferWITHOUT drive torqueMleft < Mright
400 Nm500 Nm 500 500
1000
100900
BMW Dynamic Performance Control.Summary Torque Flow.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 21
Planetary gear opens second load path
Force transferindependentof drive torque
Same behaviour as with conventional final driveDriving straight-ahead:Planetary gear circulates “in a block“In a bend:Planetary gear rolls without load
WITHOUT torque transferMleft = Mright
WITH torque transferMleft < Mright
Mleft < Mright
BMW Dynamic Performance Control:Mode of Operation
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 22
Benefits:
• improvedresponsiveness
• optimized traction in bends and fromstandstill
• increased yawdamping
• reduced understeer
conventionalrear axle differential
Rear axle differential with torque vectoring
BMW Dynamic Performance Control.Function: Avoiding Understeer.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 23
Dynamic Performance Control xDrive
1
23
4
5
BMW Dynamic Performance Control.Function: Avoiding Understeer.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 24
Requiredsteering angle
Steering precision and stability in bends with BMW Dynamic Performance Control.
Steering precision and stablity in bends withoutBMW Dynamic Performance Control.
Understeering without BMW Dynamic Performance Control.
Stable driving in a bend with turn in yaw moment through BMW Dynamic Performance Control.
BMW Dynamic Performance Control.ISO Lane Change.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 25
x-coordinate [m]60 80 100 120 140 160
Vehicle speed
Veh
icle
spee
d[k
m/h
] 115.2
113.4
111.6
109.8
108.0
106.2
x-coordinate [m]60 80 100 120 140 160
Mean difference in speed of car: 3.3 [km/h]
withwithout
Dynamic Performance Control
Higher speed at entry
Higher average speed
Improvement byBMW DynamicPerformance Control
No counter-steeringin the second lane
Less counter-steeringin the third lane
Lower steering forces
150
100
50
0
-50
-100
-150
Steering angleS
teer
ing
angl
e [°
]
Mean difference in steering angle effort: 20.6 [°]
Driver Assistance Systems & Active SafetyDriver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 26
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
BMW Active SteeringBasic Construction
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 27
Electric Motor
PlanetaryGear
Components of aMechatronic System:
• one or severalelectrical / mechanicalenergy converters,(i. e. electric motorsor generators),
• electronic control unit,
• additional mechanicalequipment, e. g. gears, connecting rods.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 28
Superposition GearingBasic Function
complete form-fitmechanical connectionSteering angle superpositionreal feedback torqueinherent fail-safe
to powersteering
fromsteering wheel
z1
z2
z3
z4
Zworm gear
BMW Active Steering:Variable Steering Ratio
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 29
System Function: Variable Steering Ratio
speed [km/h]
stee
ring
ratio
conventional cars
Active Steering
Optimal control at high vehicle speed
Improvedcontrollabilityin dynamicmanoeuvres
Improved comfort in parkingand taxiing
Improved handling and agility at low and medium vehicle speeds
System Function: Vehicle Stabilization
BMW Active Steering:Vehicle Control together with DSC
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 30
Less dominant braking activities, improved drivingdynamics
Maximum vehicle stability via combined steering and braking control
Support of the driver for vehiclestabilization
BMW Active Steering.Yaw Rate Control.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 31
Conventional Steering + DSC
Active Steering + DSC
Stabilising Brake Control (DSC)Engine Torque ControlStabilising Steering Control (Active Steering)
BMW Active Steering.Yaw Moment Compensation.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 32
Low µ
High µ
Lane change
w/o steering
control
Wheel Brake ForceVehicle Speed
Yaw MomentStabilising Steering Control
Driver Assistance Systems & Active SafetyDriver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 33
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
BMW Integrated Chassis Management (ICM)Master Control Unit DSC
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 34
DSC
BrakexDrive Electro-MechanicParking Brake Actuator
Active SteeringHigh level controlsoftware of DSC, xDrive, and parkingbrake implementedin DSC ECU, interface to ActiveSteering ECU via CAN bus.
Integrated Chassis Management.New Potentials for Active Safety.
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 35
ICMIntegrated Chassis
Management
SupervisionControl Systems
SteeringControl Systems
BrakeControl Systems
AssistanceControl Systems
RideControl Systems
Driver Assistance Systems & Active SafetyDriver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 36
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
Predictive Active Safety: Adaptive Brake AssistReduction of Stopping Distance
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 37
30m
pressure rise
60m
Maximum pedal force
100m
stop
0
100 km/h
potential for reductionof stopping distance
28m
Reaction time
Adaptive Brake Assist.In Case of Inattention …
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 38
Hesitating driver recognizes unexpectedobstacle on the street
Reduces stopping distance in case of
Prefill
Prefill and Brake Assist
WithoutAssistance
40m 30m
2m due to prefill time
2m
unexpected braking of leading vehicle orclosing up on slow vehicles
Reduced stopping distance due to maximum deceleration
100km/h
100km/h
100km/h
40m 30m
40m
Collision Warning.In Case of Inattention …
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 39
Reduces overall stopping distance using an additional driver warning
Prefill
Prefill and Brake Assist
WithoutAssistance
2m due to prefill time
2mWarning Reaction
40m 30m
40m 30m
40m
40m
Reduced overall stopping distance because of faster reaction due tocollision warning
Driver Assistance Systems & Active SafetyDriver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 40
Overview
BMW xDrive
Torque Vectoring: Dynamic Performance Control (DPC)
BMW Active Steering
System Integration: BMW Integrated Chassis Management (ICM)
Predictive Active Safety: Adaptive Brake Assistant
Further Driver Assistant Systems to– improve perception & interaction–facilitate driving tasks–optimal driver information
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 41
Comfortable and fast input of e.g.:- destinations into navigation system - telephone calls by number or by name- radio stations or CD-Titlesthrough extremely reliable whole-word voice recognition.
Whole-Word Voice recognition:Keeps the hands on the steering wheeland the eyes on the road
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 42
Head-Up Display:Driver has all the important information whilestill paying attention to traffic
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 43
60km/h60km/h
Distance control in flowing traffic and when driving dead slow.
0km/h
Aktive Cruise Control with Stop&Go FunctionAutomated speed and distance control in exhausting traffic situations
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 44
Intuitive warning:Steering wheel vibrates lightly on unintentional lane deviations.
Lane Departure WarningAlways safe on course
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 45
Automatic switching off of headlights in the event of oncoming traffic, vehicle ahead and in lit built-up areas.
High-Beam AssistantUnique feature for automated headlamp dimming
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 46
Thermal image camera
Thermal image cameraidentifies persons, animals and objects at the roadside up to a distance of 300 meters.
BMW Night Vision:Highest degree of safety when driving at night
Vision:Enhanced Network/Integration of all Systems
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 47
Active Safety
Stability Control
Driver Assistance
to keep the vehiclesafely on track
Driver Assistance & Active Safety SystemsK-H KustermannBMW GroupSeite 48
Active SafetyConclusion
Active Safety is real teamwork:
A precisely designed layout of
chassis components and premium stability control systems plus an array of predictive active safety systems
keep the vehicle safely on track - even in the mostdemanding situations.
BMW Driver Assistance Systems &Active Safety Systems
Karl-Heinz KustermannEngineering Division (China)
China International Automotive Congress 20082008, Oct. 30th – Nov. 1stShenyang, China
Dr. Heinz Leffler, Dr. Joachim Steinle Vehicle Dynamics Development
Thank you for your attention!