All Wheel Control for Electric Drive Vehicles - Outlander PHEV S-AWC - May, 2019 MITSUBISHI MOTORS EV/Powertrain Engineering Development Div. Kaoru SAWASE, Ph.D. & Tomo KATO 1
All Wheel Control History 1987 1990 1996 1999 2003 2007 2010 2013 2019 Technology Development Concept 6th Galant VR-4 (1987) Grandis (2003) [4WD/4WS/ABS] [EC-4WD] 8th Galant VR-4 (1996) [AYC/ASC] Integrated Vehicle Dynamics Control System Lancer Evolution VII (2001) Diamante (1990) [ACD] [TCL] Outlander (2010) Eclipse Cross (2017) 2nd Pajero (1991) 3rd Pajero (1999) [SS4] [SS4- Ⅱ ] Lancer Evolution X (2007) Outlander PHEV (2013) 2
AWC : Technology Development Concept To provide “ Driving pleasure ” and “ Toughness & Safety ” by making the best use of four tire friction forces (since 1987) longitudinal G tire friction circle longitudinal acceleration G force side force lateral G center of gravity lateral G deceleration G four wheel model G bowl 3
S-AWC : Integrated Vehicle Dynamics Control System Integrated Vehicle Dynamics Control System Lateral Torque Vectoring 4-wheel Brake Control Longitudinal Torque Distribution ABS 4WD AYC ＆ ASC acceleration G acceleration G acceleration G lateral G lateral G lateral G effective Area effective area effective area deceleration G deceleration G deceleration G 4
Longitudinal Torque Distribution 3 kinds of device with different characteristics Device Differential Gear Clutch E-Motor Configuration System M engine engine differential gear E-motor T/M T/M E-motor clutch M < In case of FWD vehicle base > Torque Distribution rear wheel torque rear wheel torque rear wheel torque Characteristics limit by clutch torque flexible distribution during only fixed distribution FW speed > RW speed by design phase front wheel torque front wheel torque front wheel torque 5
Target Dynamic Performance of S-AWC “Confident Driving” as a vehicle behavior is faithful to the driver’s input, namely accelerator, steering, and brake, under any driving condition. 5 Ideal target Electrified 4WD handling & stability performance 4 OUTLANDER PHEV (S-AWC) ECLIPSE CROSS 3 (S-AWC) European European Vehicle D Confident Driving ICE FF Vehicle C 4WD PAJERO SPORT 2 ICE FR Japanese Japanese 4WD Vehicle A Vehicle B 1 0 0 1 2 3 4 5 traction performance 6
Control Policy of S-AWC Smooth and seamless control provides predictable vehicle behavior acceleration G control for traction control for traction 4WD control for cornering mixing at control for cornering AYC lateral G anytime vehicle behavior control for stability ABS&ASC control for stability deceleration G acceleration G Usual Control control for traction control for control for traction 4WD cornering AYC control for cornering lateral G switching by vehicle behavior control for stability ABS&ASC situation control for stability 7 deceleration G
Control Policy of S-AWC To realize robust vehicle behavior for various driving conditions snow road dry paved road w/ S-AWC w/ S-AWC snow road w/o S-AWC dry paved road w/o S-AWC steer angle / base steer angle 30R small difference from dry drive to course paved road characteristics mild acceleration stability cornering characteristics test factor : A 1 predictable cornering limit lateral G 8
Lancer Evolution X S-AWC The All Weather Sport Sedan, the first application of S-AWC （ 2007-2015 ） Longitudinal Torque Distribution ： ACD Lateral Torque Vectoring ： AYC Differential + Brake AYC 4-wheel Brake Control ： ABS & ASC 9
Outlander PHEV S-AWC Plugin Hybrid EV equipped with state-of-the-art S-AWC （ 2013- ） Brake AYC ABS/ASC unit Yaw Moment PHEV ECU Twin Motor 4WD (S-AWC Controller) Longitudinal Torque Distribution ： Twin Motor 4WD Lateral Torque Vectoring ： Brake AYC 4-wheel Brake Control ： ABS & ASC 10
Advantage of Twin Motor 4WD 3 Advantages ideal control of high flexibility of highly efficient longitudinal torque torque control 4WD system distribution responses driving torque response characteristics ０ time 11
Control Diagram of Twin Motor 4WD Basic Distribution Control to realize Ideal Longitudinal Torque Distribution T F0 Front drive torque T F ＋ Total drive torque T Basic Distribution Basic Distribution ＋ Control Control T R0 Rear drive torque T R ＋ － Feedback Control T DNFB Target Slip Difference ＋ Control T FB T YRFB Yaw Rate Feedback ＋ Control 12
Ideal Longitudinal Torque Distribution Led from 4-wheel model G X :Longitudinal G G Ymax :Maximum Lateral G Tire Friction Circle G Yfmax , G Yrmax :Maximum R i : Radius Front / Rear Lateral G G X T f , T r :Front / Rear Distribution Torque D i T vf , T vr :Front / Rear Vectoring Torque T vf M f , M r :Yaw Moment Generated G Yfmax by Front / Rear Torque Vectoring R i :Tire Friction Force of i D i :Driving Force of i C mi :Maximum Cornering Force of i T f i = fl , fr , rl , rr :Wheel Position G Ymax C mi (Front Left, Front Right, Engine Rear Left, Rear Right) M g = M f + M r m f , m r :Front / Rear Vehicle Mass T r L :Wheel Base H g :Height of Center of Gravity G Yrmax W f , W r :Front / Rear Track K f , K r :Front / Rear Vehicle Roll Stiffness H f , H r :Height of Front / Rear Roll Center H s :Distance between Center of Gravity and Roll Axis T vr 13
Ideal Longitudinal Torque Distribution Analysis result on μ = 1.0 Rear Wheel Torque[Nm] GY ( μ = 1.0 ) 14 Front Wheel Torque[Nm]
Ideal Longitudinal Torque Distribution Analysis result on μ = 0.7 Rear Wheel Torque[Nm] GY ( μ = 0.7 ) 15 Front Wheel Torque[Nm]
Ideal Longitudinal Torque Distribution Analysis result on μ = 0.4 Rear Wheel Torque[Nm] GY ( μ = 0.4 ) 16 Front Wheel Torque[Nm]
Ideal Longitudinal Torque Distribution Ideal distribution is achieved from GX and GY as k F GY = 0G Rear Wheel Torque[Nm] GY = 0.2G Basic Distribution Control Total Drive Torque GY = 0.4G Longitudinal Acceleration Front Wheel Lateral Basic Acceleration Distribution GY = 0.6G Ratio k F = a / ( a + b ) b 0 a Front Wheel Torque[Nm] 17
Effect of Ideal Longitudinal Torque Distribution Achieve smooth vehicle behavior Road : Packed snow Steering : Fix Accelerator : 50% Front wheel drive base cont. Rear wheel drive base cont. Ideal Distribution cont. 18
Conclusion Technology development concept AWC was described. • Integrated vehicle dynamics control system S-AWC was defined, and its • target performance, control policy and the configuration of each vehicles were described. The ideal longitudinal torque distribution, the method to realize it in Twin • Motor 4WD, and its effect were described. 19
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