Advanced Stability Control of Electric Vehicle with Advanced Stability Control of Electric Vehicle with InIn--wheel Motor and Active Steering Systemwheel Motor and Active Steering SystemInIn wheel Motor and Active Steering Systemwheel Motor and Active Steering SystemHiroshi Fujimoto (([email protected]@k.u--tokyo.ac.jptokyo.ac.jp))
The University of Tokyo
Slide 1H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))http://hflab.k.u-tokyo.ac.jp/
Hori/Fujimoto Lab.
Dept. Advanced Energy Dept. Electrical Eng.Frontier Sciences (Kashiwa) Grad. School of Eng. (Hongo)
Research Field: Control Engineering, Motion Control, Electric Vehicle, Research Field: Control Engineering, Motion Control, Electric Vehicle, Wireless Power Transfer, Wireless Power Transfer, NanoNano--scale Servo, Power Electronics, Robotics, scale Servo, Power Electronics, Robotics,
Lab Members: 8 staffs (P, AP, Assistant P, 2 PDs, Engineer, 2 secretaries) 33 students (9 Ph.D, 19 M.S., 4 B.S., 1 R.S. , including 13 international students)students)
EV Garage (250EV Garage (250㎡㎡) )
ff ㎡㎡EV test field (2600EV test field (2600㎡㎡))
Slide 2H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Kashiwa New Campus Kashiwa New Campus (40 min from center of Tokyo)(40 min from center of Tokyo)
Motion Control of EVs over ICVs[Y.Hori, TIE ‘04]
Advantages of motors →High Control Perf.f
■ Quick torque response Ni
f
Torque of Motors (1ms)
>> Torque of Engines (500ms)S
iB
>> Torque of Engines (500ms)
→ Anti-slip Controlp
■Measurable torque
→ Estimate of Road Cond.
■I di id l h l t l b IWMSlide 3
H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
■Individual wheel control by IWMs
→ Vehicle Stability Control in 2D
ContentsContents
1.1. IntroductionIntroduction
l d l f ll d l f l2.2. Development and Control of Original EV FPEV2Development and Control of Original EV FPEV2--KanonKanon
3.3. Vehicle Stability Control with Wheel Side Force SensorVehicle Stability Control with Wheel Side Force Sensor
4.4. Range Extension Control SystemRange Extension Control System
55 ConclusionConclusion5.5. ConclusionConclusion
Slide 4H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
In-wheel motorsOuter rotor type
Big torque generation
F t R
Direct drive systemNo Transmission Loss of GearHi h Effi i d S ll N i Front Rear
Maker Toyo Denki Seizo K.K., Ltd
Motor type Outer rotor type
High Efficiency and Small NoiseQuick responseEstimation by reaction force
Motor type Outer rotor type
Direct drive system
Rated torque 110[Nm] 137[Nm][ ] [ ]Max torque 500[Nm] 340[Nm]Rated power 6.0[kW] 4.3[kW]Max power 20.0[kW] 10.7[kW]Max speed 1113[rpm] 1500[rpm]
Slide 5H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Motor mass 32[kg] 26[kg]Cooling Natural air cooling
FPEVFPEV--2(Kanon)2(Kanon)Future Personal Electric Vehicle
FPEVFPEV 2(Kanon)2(Kanon)
Inverter andChopper Li-ion BatteryChopper
ECU
Li ion Battery
ECU
Steer-by-wire and
DD in-wheel motors4WS (Front and Rear Steering Control by
Motors)Slide 6
H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Motors)Side force sensors
Active Front/Rear Active Front/Rear Stee ing S stemStee ing S stem
• 2 DC Motors (Maxon 250W) for Steering
Steering SystemSteering System •Front steering shaft is removable.→Steer-by-wire
Slide 7H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Development of Original EVDevelopment of Original EV
Slide 8H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Principle of Driving Force EstimationPrinciple of Driving Force Estimation
mMotion Equation of WheelMotion Equation of Wheel
r
m
dRadius of wheelRadius of wheel
TJdrFTJ
dtd
dtInertia of wheelInertia of wheel
FFdd :Drive.Force:Drive.Force
Angular AccelAngular Accel
Motor torqueMotor torque
→→Measured byMeasured byInertia of wheelInertia of wheel
→→Constant Constant
Angular Accel.Angular Accel.
→→Measured byMeasured by
SensorsSensors
CurrentCurrent
Driving Force FDriving Force Fdd can be estimated by this equation. can be estimated by this equation. I t it i l l t d lti ith 0 1I t it i l l t d lti ith 0 1
Slide 9H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
In our system, it is calculated realtime with 0.1ms In our system, it is calculated realtime with 0.1ms sampling. sampling.
AntiAnti--slip Control slip Control
+ Wheel Speed
Dynamics of EV
+Accel. Signal Wheel SpeedTorque Command-
Swithc
Inverse Dynamics on Grip+-gain
Slip TorqueToque on adhesionw.r.t wheel speed
ControllerController
Slide 10H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))Without controlWithout control With controlWith control
Direct Yaw Control (DYC)Direct Yaw Control (DYC)
Slide 11H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Yaw rate
DYC resultsDYC results
Without controlWithout controlWithout controlWithout control
Wi hWi h ll
Counter steering
With With controlcontrol
g
Slide 12H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
With controlWith controlWithout controlWithout control
SlipSlip--ratio Control with Regenerative Brakingratio Control with Regenerative Braking
Mechanical Braking Only Mechanical Braking Only Electric and Mechanical BrakingElectric and Mechanical Braking
Slide 13H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Collaboration with Mitsubishi MotorsCollaboration with Mitsubishi Motors
Slide 14H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
ContentsContents
1.1. IntroductionIntroduction
l d l f ll d l f l2.2. Development and Control of Original EV FPEV2Development and Control of Original EV FPEV2--KanonKanon
3.3. Vehicle Stability Control with Wheel Side Force SensorVehicle Stability Control with Wheel Side Force Sensor
i.i. Lateral Force SensorLateral Force Sensor
iiii YawYaw rate Control by IWMs and Active Front/Rearrate Control by IWMs and Active Front/Rearii.ii. YawYaw--rate Control by IWMs and Active Front/Rear rate Control by IWMs and Active Front/Rear SteeringSteering
44 R E i C l SR E i C l S4.4. Range Extension Control SystemRange Extension Control System
5.5. ConclusionConclusion
Slide 15H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Research and Development of Yaw ControlResearch and Development of Yaw Control
ESC:Electronic Stability ControlS bili h hi l i b lli b 4 h l b kSystem to stabilize the vehicle motion by controlling yaw-rate by 4 wheel brakeindependently. One of the active safety technologies. ESCs have already been implemented in many commercialize cars.
A study of dynamics performance improvement by rear right and left
implemented in many commercialize cars.
independent drive system [Sugano (Mazda)]Friction circle estimation and integrated control of 4 wheels independent dive
and 4WS [Ono (Toyota CRL)]El t i C t l T S lit 4WDElectric Control Torque Split 4WD [Nissan]Development of 4 wheel driving force control system [Mori (Honda)]Integrated Vehicle Motion Control System“S-AWC” [Miura (Mitsubishi Motors)]Motion Control of Electric Vehicle ith Tire Workload [I (B id t )]Motion Control of Electric Vehicle with Tire Workload [Iwano (Bridgestone)]Effects of Model Response on Model Following Type of Combined Lateral Force
and Yaw Moment Control Performance for Active Vehicle Handling Safety[O.Mokhiamar (Kanagawa U)]
Slide 16H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
[O o a a ( a aga a U)]Mini-max Optimal Distribution of Lateral and Driving/Braking Forces
[Nishihara (Kyoto Univ)]
Wheel Lateral Force SensorWheel Lateral Force Sensor Slip Angle
• Lateral force detection by sensors in Hub-unit• Possible to measure lateral force under suspension• Possible to measure lateral force under suspension
Velocity
Lateral Force
Normallyunknown
– Expected Big Contribution to Active Safety– Intelligent wheels by these sensors and in-wheel
motors (and steer-by-wire)motors (and steer-by-wire)
• Recent development in Japan– NSK : Sensing by wheel speed sensor and encorders
Slide 17H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
– NTN : Sensing by strain gauge– J-Tekt
ContentsContents
1.1. IntroductionIntroduction
l d l f ll d l f l2.2. Development and Control of Original EV FPEV2Development and Control of Original EV FPEV2--KanonKanon
3.3. Vehicle Stability Control with Wheel Side Force SensorVehicle Stability Control with Wheel Side Force Sensor
i.i. Lateral Force SensorLateral Force Sensor
iiii YawYaw rate Control by IWMs and Active Front/Rearrate Control by IWMs and Active Front/Rearii.ii. YawYaw--rate Control by IWMs and Active Front/Rear rate Control by IWMs and Active Front/Rear SteeringSteering
44 R E i C l SR E i C l S4.4. Range Extension Control SystemRange Extension Control System
5.5. ConclusionConclusion
Slide 18H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
��
Equation of Motion for 4 wheels independent drive/steering
・Longitudinal Motion ���� ����Æ� Æ����
���� ����
・Lateral Motion
�Æ Æ
��
���
�
��
・Yawing Motion
��������
� ���
��
���� ����
)1( f Yawing Motion
��
(Driving/Braking Force Diff.)
)1,( rf
(Moment by Lateral Force)
Active steering or 4 wheel ・Sum of squares workload minimization (Abe03)
Slide 19H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
independent vehicles have redundancy in control input.
minimization (Abe03)
・Minimax (Nishihara06)
・Workload equalization (Ono07)
Load change in decelerating turning
Force saturationDecrease of yaw-moment caused by saturation destabilizes vehicle Force saturation
on rear lefty
motion.
Slide 20H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Yaw-control of front/rear independent steering and rear IWMs
�
[Ando, Fujimoto, AMC10][Ando, Fujimoto, AMC10]
���� ����� �
��
���
���� ����
A x
FF 22 �����
� ����
���
�
��
z
yx
FFF
η 22
Workload
��������
� �
��
��
���� ����
FF Tyijxij 22
Objective function: sum of squares of workload
�
Friction circleFriction circle
�����
Æ
WxxF
J T
rljrfi zij
yijxij ,,,
2
O i l di ib i
��
Optimal distribution
Slide 21H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Example of force Example of force saturationsaturation
Conventional (YMO): torque diff. only Optimal method: torque diff. and front/rear steering/ g
Test by decelerating turning
Accelerates to 30km/h →step-type steering ( =0.06rad)fp yp g ( )
Decelerating turning with braking force -800N
C d i l t t t i diSlide 22
H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Command signals: constant turning radiusfyf l
ValV
2
*,*
Movie of ExperimentspTorque diff and active F/R steerTorque difference only
Slide 23H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Red: Force Vector Locus,Blue: wheel load,Blue dashed: Amplitude of force
Control input in experimentsControl input in experiments
Torque diff and active F/R steerTorque difference only
SteeringSteering
TorqueCommand
Slide 24H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Experimental results (yawExperimental results (yaw--rate, workload)rate, workload)
Torque diff and active F/R steerTorque difference only
Yawraterate
E li tiEqualizationof each wheelworkload
Workload
Slide 25H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
ContentsContents
1.1. IntroductionIntroduction
l d l f ll d l f l2.2. Development and Control of Original EV FPEV2Development and Control of Original EV FPEV2--KanonKanon
3.3. Vehicle Stability Control with Wheel Side Force SensorVehicle Stability Control with Wheel Side Force Sensor
4.4. Range Extension Control SystemRange Extension Control System
55 ConclusionConclusion5.5. ConclusionConclusion
Slide 26H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Critical Problem of EVs
Critical issues for EVsCritical issues for EVs Mileage per chargeMileage per chargeCritical issues for EVsCritical issues for EVs Mileage per chargeMileage per charge
Comparison of ICV and electric vehicleComparison of ICV and electric vehicle
mileagemileage capacitycapacity cruising ragecruising rageGasoline vehicleGasoline vehicle ((ii) 21 km/L) 21 km/L ((gasoline 35Lgasoline 35L)) 735km735km
Electric vehicleElectric vehicle((ii--MiEVMiEV))88 km/kWhkm/kWh ((battery capacity 16 kWhbattery capacity 16 kWh)) 130km130km
[M. [M. KamachiKamachi, AVEC08], AVEC08]
EV’s cruising range is shorter than ICV’s range.EV’s cruising range is shorter than ICV’s range.
・・High efficiency motorHigh efficiency motor・・Novel driving method by two reduction gearNovel driving method by two reduction gear
In order to solve this problemIn order to solve this problem・・・・・・
[K. Sakai, JIASC09][K. Sakai, JIASC09][A Sorniotti AVEC10][A Sorniotti AVEC10]
Slide 27H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
・・Novel driving method by two reduction gearNovel driving method by two reduction gear [A. Sorniotti, AVEC10][A. Sorniotti, AVEC10]
Range Extension Control System: RECSRange Extension Control System: RECSTry to enhance the cruising range of EV’s by control technologiesTry to enhance the cruising range of EV’s by control technologies
(Assumption: EV has multiple motors)(Assumption: EV has multiple motors)
3 3 types of RECS types of RECS developeddeveloped••RECS I: Optimal torque RECS I: Optimal torque distributiondistribution••RECS II: Minimization the corneringRECS II: Minimization the cornering resistanceresistance
[Fujimoto, [Fujimoto, SumiyaSumiya IECON2011]IECON2011]••RECS II: Minimization the cornering RECS II: Minimization the cornering resistanceresistance••RECS III: Minimization motor output RECS III: Minimization motor output [[EgamiEgami, Fujimoto, IECON2011], Fujimoto, IECON2011]••Total optimization (RECS I + III) [Fujimoto, Total optimization (RECS I + III) [Fujimoto, EgamiEgami, IECON2012], IECON2012]p ( ) [ j ,p ( ) [ j , gg , ], ]
B ttB tt
RECS III RECS III
BatteryBattery(+ (+
Chopper)Chopper)Inv. Inv. 11 MM11
…… ……V hi lV hi l
V
Inv. Inv. 44 MM44…… ……
VehicleVehicle
Slide 28
H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
44 44 RECS IRECS I RECS IIRECS II
RECS I: Optimal torque distributionRECS I: Optimal torque distribution
Assumption: Front and rear independent motors Straight roadAssumption: Front and rear independent motors Straight roadAssumption: Front and rear independent motors. Straight roadAssumption: Front and rear independent motors. Straight roadThe sum of the torque only needs to The sum of the torque only needs to
satisfy the driver demands.satisfy the driver demands.
Torque distribution Torque distribution
Same accelerationSame acceleration
Front Front RearRear
Slide 29H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
29Efficiency map of motor + inverterEfficiency map of motor + inverter
Optimize overall efficiency by Optimize overall efficiency by distibutiondistibution
Experiment of RECS IExperiment of RECS IExperimental conditionsExperimental conditions
••Speed command:Speed command:••Total torque command:Total torque command:E l i hE l i h h i dh i d••Evaluation on the Evaluation on the chassis dynamometer chassis dynamometer
opt
Extended mileageExtended mileage
••1 kWh1 kWh 500 m500 m••1 kWh 1 kWh 500 m500 m••16kWh 16kWh 8 km8 km
Slide 30H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
30
Collaboration with Mitsubishi Motors Front MotorFront MotorFront MotorFront Motor
Rear MotorRear Motor
Prototype PHEV with 2 onPrototype PHEV with 2 on--board motorsboard motors・・2 motors has different efficiency map.2 motors has different efficiency map.・・2 differential gears for F/R wheels2 differential gears for F/R wheels
Proposed method Proposed method 1.0[kW]1.0[kW] reductionreduction
・・2 differential gears for F/R wheels2 differential gears for F/R wheels
・・Engine is stopped. Engine is stopped. Evaluate as Battery EVEvaluate as Battery EV
EV cruising range extensionEV cruising range extensionEV cruising range extensionEV cruising range extensionCruising distance [km/kWh]Cruising distance [km/kWh] (at 50km/h constant speed)(at 50km/h constant speed)
Slide 31H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
1.52km extend per 1kWh1.52km extend per 1kWh24.2km extend per 16kWh 24.2km extend per 16kWh
RECSII: Cornering resistance minimizationRECS on curving road by left and right independent motorsRECS on curving road by left and right independent motors
c p
Mi i i f t t i lMi i i f t t i l bb N
c
Cornering resistanceCornering resistance
Minimize front steering angleMinimize front steering angle by by zN
Cornering resistanceCornering resistanceis reducedis reduced
<Conventional><Conventional> <Proposed><Proposed>
Cornering resistanceCornering resistanceMileage per charge is extended!Mileage per charge is extended!
pc
Cornering resistanceCornering resistance
Driving forceDriving force
Slide 32H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
: yaw: yaw--moment generated by driving force moment generated by driving force difference between left and right motorsdifference between left and right motors
zN
Cruse distance (km/kWh)Cruse distance (km/kWh)( / )( / )
<Conventional><Conventional> <Proposed><Proposed>
Slide 33H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
33
••V=15 [km/h]V=15 [km/h],,R=8 [m]R=8 [m]Input power of Input power of inveterinveter Front Steering AngleFront Steering Angle
Control Technologies of EV Developed in Control Technologies of EV Developed in Hori/Fujimoto Hori/Fujimoto Lab.Lab.
Advanced Safty
•Slip-ratio control•Yaw-rage controlYaw rage control•Slip-angle control•…..
Driving Comfort
Pit hi t l
Range ExtensionControl System
•Pitching control•Roll control •Optimal Distribution
•Minimize Resistance
Slide 34H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
Minimize Resistance
ConclusionConclusion
1.1. SmallSmall--scale EV “FPEV2scale EV “FPEV2--Kanon” are designed and developed Kanon” are designed and developed with active front/rear steering and direct drive inwith active front/rear steering and direct drive in--wheel wheel motors.motors.
2.2. Control theories developed with FPEV2Control theories developed with FPEV2--Kanon was applied to Kanon was applied to the prototype EVs ofthe prototype EVs of industiresindustires..the prototype EVs of the prototype EVs of industiresindustires..
3.3. Developed technologies are available not only Battery EVs Developed technologies are available not only Battery EVs but also (Plugbut also (Plug--in) hybrid vehicles and FCEVs.in) hybrid vehicles and FCEVs.
Slide 35H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
New Developing EV (FPEV4 Sawyer) New Developing EV (FPEV4 Sawyer) Main UnitMain Unit
LiLi--ionion BatteryBattery
L/R Individual OnL/R Individual On--board Motorboard Motor(N of Turns:(N of Turns: 42T/21T)42T/21T)
InIn--wheel Motorwheel Motor(N of Turns:(N of Turns: 12T/8T)12T/8T)
SubSub--unitunit(N of Turns: (N of Turns: 42T/21T)42T/21T) (N of Turns: (N of Turns: 12T/8T)12T/8T)
Left/Right Individual OnLeft/Right Individual On--OnOn--board motor / board motor / InIn--wheel motorswheel motorsNonNon--driven Unitdriven Unit
Drive Unit in SubDrive Unit in Sub--unit which is installed both rear and frontunit which is installed both rear and front>M fi ti i d ith f i i>M fi ti i d ith f i i
board Motorboard MotorDifferential Gear Differential Gear
=>Many configurations are examined with fair comparison=>Many configurations are examined with fair comparisonProvide common test platform (e.g. OnProvide common test platform (e.g. On--board motor + board motor + Drive shaft vibration Drive shaft vibration supressionsupression control = IWM?)control = IWM?)Active Front and Rear Steering, Steer by wireActive Front and Rear Steering, Steer by wire
Slide 36H.FujimotoH.Fujimoto ((Univ.TokyoUniv.Tokyo))
36g, yg, y
Suspension geometry is tunableSuspension geometry is tunableLateral force sensorsLateral force sensors Test driveTest drive@@EV test field in KashiwaEV test field in Kashiwa