tire wear affecting motorcycle dynamic€¦ · • increase of wear →increase of tire stiffness,...
TRANSCRIPT
IPG Automotive – Apply & Innovate TECH WEEKS 20201 02/09/2020
Research partnership in technology innovation
Title
Tire wear affecting motorcycle dynamicElisabetta Leo, Christian Pagliara, Marco E. Pezzola
Soluzioni Ingegneria srl
IPG Automotive – Apply & Innovate TECH WEEKS 20202 02/09/2020
INTRO & MOTIVATIONS
TIRE OPERATIVE CONDITIONS CHANGE WHILE RIDING
IPG Automotive – Apply & Innovate TECH WEEKS 20203 02/09/2020
INTRO & MOTIVATIONS
DIFFERENT OPERATIVE CONDITIONS MEANS:
DIFFERENT TIRE BEHAVIOUR
Stability LongitudinalPerformance
Handling
DIFFERENT MOTORCYCLE BEHAVIOUR
MOTORCYCLE BEHAVIOUR SHOULD BE VERIFIED FOR ALL THE PLAUSIBLE TIRE’S OPERATIVE CONDITIONS
IPG Automotive – Apply & Innovate TECH WEEKS 20204 02/09/2020
TARGET
TO INVESTIGATE THE EFFECTS OF TIRE WEAR ON BOTH THE LATERAL AND THE LONGITUDINAL
MOTORCYCLE DYNAMIC
TO PROPOSE A PACEJKA MF MODIFICATION INCLUDING THE WEAR DEPENDENCY
WEAR
IPG Automotive – Apply & Innovate TECH WEEKS 20205 02/09/2020
OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
IPG Automotive – Apply & Innovate TECH WEEKS 20206 02/09/2020
OUTDOOR TESTSInstrumentation
1High performance GPS → vehicle speed, longitudinal/lateralacceleration
3 Front tire encoder → angular speed2 Rear tire encoder
→ angulare speed
4 Strain gauges→steerig torque (lateral dynamic)
IPG Automotive – Apply & Innovate TECH WEEKS 20207 02/09/2020
OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
IPG Automotive – Apply & Innovate TECH WEEKS 20208 02/09/2020
FULL BRAKING MANOEUVER.• ABS system status: active• Vehicle speed before braking: constant@85 km/h• 15x test repetitions, at least
LONG. DYN.: OUTDOOR TESTTest Scenario&manoeuver
ROAD MANOEUVER
Straight line roadHigh grip surface (dry tarmac)
IPG Automotive – Apply & Innovate TECH WEEKS 20209 02/09/2020
FULL BRAKING MANOEUVER.• ABS system status: active• Vehicle speed before braking: constant@85 km/h• 15x test repetitions, at least
LONG. DYN.: OUTDOOR TESTTest Scenario&manoeuver
ROAD MANOEUVER
Straight line roadHigh grip surface (dry tarmac)
In case of worn tire:❑ lower time to halt (lower braking distance);❑ higher avarage deceleration.
IPG Automotive – Apply & Innovate TECH WEEKS 202010 02/09/2020
DIFFERENT TIRES MODELS HAVE BEEN TESTED; THE TREND HAS BEEN CONFIRMED
RIDERS PERCEPTIONS CONFIRM EXPERIMENTAL EVIDENCE
WORN TIRES PERFORM HIGHER BRAKING DECELERATION
LONG. DYN.: OUTDOOR TESTSummary
IPG Automotive – Apply & Innovate TECH WEEKS 202011 02/09/2020
LONG. DYN.
Why
IPG Automotive – Apply & Innovate TECH WEEKS 202012 02/09/2020
OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
IPG Automotive – Apply & Innovate TECH WEEKS 202013 02/09/2020
To better understand the effects of tire wear on longitudinal dynamic:
Target
❑MAXIMUM FRICTION❑ LONGITUDINAL STIFFNESS ❑ RELAXATION LENGTH𝝈𝒙(%𝒘𝒆𝒂𝒓)𝝁𝒎𝒂𝒙,𝒙(%𝒘𝒆𝒂𝒓)
LONG. DYN.: INDOOR TEST
QUASI-STATIC CHARACTERIZATION DYNAMIC CHARACTERIZATION
𝑲𝒙 (%𝒘𝒆𝒂𝒓)
MTS Flat-Trac® III
IPG Automotive – Apply & Innovate TECH WEEKS 202014 02/09/2020
To better comprehend the effects of tire wear on longitudinal dynamic:
Target
MTS Flat-Trac® III
❑MAXIMUM FRICTION❑ LONGITUDINAL STIFFNESS ❑ RELAXATION LENGTH𝝈𝒙(%𝒘𝒆𝒂𝒓)𝑲𝒙 (%𝒘𝒆𝒂𝒓) 𝝁𝒎𝒂𝒙,𝒙(%𝒘𝒆𝒂𝒓)
QUASI-STATIC CHARACTERIZATION DYNAMIC CHARACTERIZATION
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
IPG Automotive – Apply & Innovate TECH WEEKS 202015 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 5 s (0,2 Hz)
❑MEASURED LONGITUDINAL FORCE
QUASI-STATIC CHARACTERIZATION. PROCEDURE.
IPG Automotive – Apply & Innovate TECH WEEKS 202016 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 5 s (0,2 Hz)
❑MEASURED LONGITUDINAL FORCE
❑THE ENGAGED FRICTION COEFFICIENT ΜuX IS COMPUTED AND PLOT VS SLIP RATIO→ A SCATTER PLOT IS ACHIEVED
QUASI-STATIC CHARACTERIZATION. PROCEDURE.
IPG Automotive – Apply & Innovate TECH WEEKS 202017 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 5 s (0,2 Hz)
❑MEASURED LONGITUDINAL FORCE
❑THE ENGAGED FRICTION COEFFICIENT ΜuX IS COMPUTED AND PLOT VS SLIP RATIO→ A SCATTER PLOT IS ACHIEVED
❑DATA FITTING THROUGH PACEJKA MAGIC FORMULA: THE LONGITUDINAL STIFFNESS (Kx) AND THE MAXIMM GRIP (𝜇𝑚𝑎𝑥,𝑥) CAN BE IDENTIFIED
QUASI-STATIC CHARACTERIZATION. PROCEDURE.
𝝁𝒎𝒂𝒙,𝒙
𝑲𝒙
IPG Automotive – Apply & Innovate TECH WEEKS 202018 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
DATA HAVE BEEN PLOT AS A FUNCTION OF THREAD WEAR VARIATION, NAMED dTW:
dTW = - (h-h0)/h0
h0: thread height while new tireh: thread height at a generic wearing condition
QUASI-STATIC CHARACTERIZATION. NEW and WORN TYRE BEHAVIOUR.
-15 -10 -5 0 5 10 15
-1.5
-1
-0.5
0
0.5
1
1.5
Slip Ratio [%] E
ngaged frici
toon [-]
𝝁𝒎𝒂𝒙,𝒙
𝑲𝒙
IPG Automotive – Apply & Innovate TECH WEEKS 202019 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
QUASI-STATIC CHARACTERIZATION. NEW and WORN TYRE BEHAVIOUR.
REPETITION OF PREVIOUS CHARACTERIZATION FOR SEVERAL WEAR LEVEL
-15 -10 -5 0 5 10 15
-1.5
-1
-0.5
0
0.5
1
1.5
Slip Ratio [%] E
ngaged frici
toon [-]
IPG Automotive – Apply & Innovate TECH WEEKS 202020 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
QUASI-STATIC CHARACTERIZATION. NEW and WORN TYRE BEHAVIOUR.
REPETITION OF PREVIOUS CHARACTERIZATION FOR SEVERAL WEAR LEVEL
-15 -10 -5 0 5 10 15
-1.5
-1
-0.5
0
0.5
1
1.5
Slip Ratio [%] E
ngaged frici
toon [-]
IPG Automotive – Apply & Innovate TECH WEEKS 202021 02/09/2020
LONG. DYN.: INDOOR TESTLongitudinal stiffness & Maximum friction
QUASI-STATIC CHARACTERIZATION. NEW and WORN TYRE BEHAVIOUR.
BOTH THE LONGITUDINAL
STIFFNESS AND THE MAXIMUM FRICTION
COEFFICIENT INCREASE AS THE TIRE WEAR
INCREASES
dTW = - (h-h0)/h0
IPG Automotive – Apply & Innovate TECH WEEKS 202022 02/09/2020
𝑲𝒙 (%𝒘𝒆𝒂𝒓)
To better comprehend the effects of tire wear on longitudinal dynamic:
Target
MTS Flat-Trac® III
❑MAXIMUM FRICTION❑ LONGITUDINAL STIFFNESS ❑ RELAXATION LENGTH𝝈𝒙(%𝒘𝒆𝒂𝒓)𝝁𝒎𝒂𝒙,𝒙(%𝒘𝒆𝒂𝒓)
QUASI-STATIC CHARACTERIZATION DYNAMIC CHARACTERIZATION
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202023 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHTMEASUREMENT
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 1s (1 Hz)
❑GENERATED LONGITUDINAL FORCE SAMPLED AT 250 Hz
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202024 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHTMEASUREMENT
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 1s (1 Hz)
❑GENERATED LONGITUDINAL FORCE SAMPLED AT 250 Hz
❑TIME DELAY BETWEEN SLIP RATIO (INPUT) AND FORCE (OUTPUT) IS MEASURED
Δt 𝜶 𝑹𝑳
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202025 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHTMEASUREMENT
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 1s (1 Hz)
❑GENERATED LONGITUDINAL FORCE SAMPLED AT 250 Hz
❑TIME DELAY BETWEEN SLIP RATIO (INPUT) AND FORCE (OUTPUT) IS MEASURED
Δt 𝜶 𝑹𝑳
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202026 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHTMEASUREMENT
❑IMPOSED SLIP RATIO SINUSOIDAL PROFILE WITH A PERIOD OF 1s (1 Hz)
❑GENERATED LONGITUDINAL FORCE SAMPLED AT 250 Hz
❑TIME DELAY BETWEEN SLIP RATIO (INPUT) AND FORCE (OUTPUT) IS MEASURED
❑HYSTERETIC BEHAVIOR IS OBSERVED
Δt 𝜶 𝑹𝑳
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202027 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHT vs WEAR
❑ REPETITION OF PREVIOUS CHARACTERIZATION FOR EACH WEAR LEVEL
❑THE SLOPE OF WORN TIRE INCREASES SINCE THE LONGITUDINAL STIFFNESS INCREASES AND IT PRESENTS WIDER HYSTERESIS
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202028 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHT vs WEAR
❑ REPETITION OF PREVIOUS CHARACTERIZATION FOR EACH WEAR LEVEL
❑THE SLOPE OF WORN TIRE INCREASES SINCE THE LONGITUDINAL STIFFNESS INCREASES AND IT PRESENTS WIDER HYSTERESIS
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202029 02/09/2020
DYNAMIC MTS CHARACTERIZATION
RELAXATION LENGHT vs WEAR
❑ REPETITION OF PREVIOUS CHARACTERIZATION FOR EACH WEAR LEVEL
❑THE SLOPE OF WORN TIRE INCREASES SINCE THE LONGITUDINAL STIFFNESS INCREASES AND IT PRESENTS WIDER HYSTERESIS
LONG. DYN.: INDOOR TESTRelaxation length
IPG Automotive – Apply & Innovate TECH WEEKS 202030 02/09/2020
The proposed results state:
THE RELAXATION LENGTH INCREASES AS THE TIRE WEAR INCREASES.
LONG. DYN.: INDOOR TESTSummary
dTW = - (h-h0)/h0
IPG Automotive – Apply & Innovate TECH WEEKS 202031 02/09/2020
THE HIGHER BRAKING PERFORMANCES OBSERVED DURING OUTDOOR TESTS ARE DUE TO HIGHER GRIP
(relaxation length and longitudinal stiffness have no perceivable effects instead)
LONG. DYN.: OUTDOOR TESTResults Explanation
IPG Automotive – Apply & Innovate TECH WEEKS 202032 02/09/2020
OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
IPG Automotive – Apply & Innovate TECH WEEKS 202033 02/09/2020
TRENDS
MF MODIFICATION TO INCLUDE WEAR EFFECTLongitudinal stiffness, relaxation length, maximum friction
Longitudinal stiffness FITTING EQUATIONS
Kxκ = Fz (pkx1 + pkx2dfz) exp(pkx3dfz)(1 + ppx1dpi + ppx2dpi2)
Kxκ = Fz (pkx1 + pkx2dfz) exp(pkx3dfz)(1 + ppx1dpi + ppx2dpi2) (1+ ptx1dTW + ptx2 dTW 2)
Pacejka 6.1 MF fitting equation:
pressure contribute
Modified equation:
wear contribute
dTW = - (h-h0)/h0
IPG Automotive – Apply & Innovate TECH WEEKS 202034 02/09/2020
TRENDS
MF MODIFICATION TO INCLUDE WEAR EFFECTLongitudinal stiffness, relaxation length, maximum friction
Longitudinal stiffness FITTING EQUATIONS
Kxκ = Fz (pkx1 + pkx2dfz) exp(pkx3dfz)(1 + ppx1dpi + ppx2dpi2)
Kxκ = Fz (pkx1 + pkx2dfz) exp(pkx3dfz)(1 + ppx1dpi + ppx2dpi2) (1+ ptx1dTW + ptx2 dTW 2)
Pacejka 6.1 MF fitting equation:
pressure contribute
Modified equation:
wear contribute
ptx1 and ptx2 identified coefficients interpolating the longitudinal stiffness VS dTW curve
dTW = - (h-h0)/h0
IPG Automotive – Apply & Innovate TECH WEEKS 202035 02/09/2020
FITTING EQUATIONS
Longitudinal stiffness Relaxation length
Kxκ = (…)*(1+ ptx1dTW + ptx2dTW2) cx = (…)*(1+ pcfx4dTW + pcfx5dTW2)
MF MODIFICATION TO INCLUDE WEAR EFFECTLongitudinal stiffness, relaxation length, maximum friction
µx = (…) (1+ ptx3dTW + ptx4dTW2)
Maximum Friction
IPG Automotive – Apply & Innovate TECH WEEKS 202036 02/09/2020
If no indoor tests are available?
ON ROAD TIRE CHARACTERIZATIONPremise
ON-ROAD CHARACTERIZATION METHODOLOGY HAS BEEN DEVELOPED
Front tire Rear tire *.tir
IPG Automotive – Apply & Innovate TECH WEEKS 202037 02/09/2020
OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
IPG Automotive – Apply & Innovate TECH WEEKS 202038 02/09/2020
LAT. DYN.: OUTDOOR TESTTest scenario
ROAD MANOEUVER
Constant radius turn (45m) executed in CCWHigh grip surface (dry tarmac)
QUASI STEADY STATE MANOEUVERSlow speed increasing; lat. jerk < 0,1 (m/s2)/s
Riding direction
IPG Automotive – Apply & Innovate TECH WEEKS 202039 02/09/2020
0 1 2 3 4 5 6 7 8
-15
-10
-5
0
5
Lateral acceleration [m/s2]
Ste
ering T
orq
ue [
Nm
]
R22m -Rider01 - RIDER OFF / Nominal pressure /NEW TYRESTEERING PAD
❑CONSTANT RADIUS:R = 45 m
❑ MOTORCYCLE SPEED:FROM 0 TO Vmax
❑QUASI STATIC CONDITION: lat. jerk < 0,1 m/s^2/s
LAT. DYN.: OUTDOOR TESTResults
IN
SI
DE
O
UT
SI
DE
Results: steering torque VS lateral accelerationManeuver and convention
10 Nm
Nominal = 2,5 [bar]
IPG Automotive – Apply & Innovate TECH WEEKS 202040 02/09/2020
0 1 2 3 4 5 6 7 8
-15
-10
-5
0
5
Lateral acceleration [m/s2]
Ste
ering T
orq
ue [
Nm
]
R22m -Rider01 - RIDER OFF / Nominal pressure /NEW TYRE
R22m -Rider01 - RIDER OFF / Nominal pressure /WORN TYRE
STEERING PAD
❑CONSTANT RADIUS:R = 45 m
❑ MOTORCYCLE SPEED:FROM 0 TO Vmax
❑QUASI STATIC CONDITION: lat. jerk < 0,1 m/s^2/s
LAT. DYN.: OUTDOOR TESTResults
IN
SI
DE
O
UT
SI
DE
Results: steering torque VS lateral accelerationManeuver and convention
-10 Nm
-15 Nm
Nominal = 2,5 [bar]
IPG Automotive – Apply & Innovate TECH WEEKS 202041 02/09/2020
0 1 2 3 4 5 6 7 8
-15
-10
-5
0
5
Lateral acceleration [m/s2]
Ste
ering T
orq
ue [
Nm
]
R22m -Rider01 - RIDER OFF / Nominal pressure /NEW TYRE
R22m -Rider01 - RIDER OFF / Nominal pressure /WORN TYRE
R22m -Rider01 - RIDER OFF / Low pressure /NEW TYRE
STEERING PAD
❑CONSTANT RADIUS:R = 45 m
❑ MOTORCYCLE SPEED:FROM 0 TO Vmax
❑QUASI STATIC CONDITION: lat. jerk < 0,1 m/s^2/s
LAT. DYN.: OUTDOOR TESTResults
IN
SI
DE
O
UT
SI
DE
Results: steering torque VS lateral accelerationManeuver and convention
-10 Nm
-15 Nm
-15 Nm
Nominal = 2,5 [bar]Low = 2,0 [bar]
IPG Automotive – Apply & Innovate TECH WEEKS 202042 02/09/2020
Different tires models have been tested.
RIDERS PERCEPTION CONFIRM EXPERIMENTAL EVIDENCE
WORN TIRE IMPLIES HIGHER OUTSIDE STEERING TORQUE.
LAT. DYN.: OUTDOOR TESTSummary
IPG Automotive – Apply & Innovate TECH WEEKS 202043 02/09/2020
LAT. DYN.
Why
IPG Automotive – Apply & Innovate TECH WEEKS 202044 02/09/2020
OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
IPG Automotive – Apply & Innovate TECH WEEKS 202045 02/09/2020
HP:
LAT. DYN.: NUMERICAL ANALYSISAssumptions
IPG Automotive – Apply & Innovate TECH WEEKS 202046 02/09/2020
HP:
LAT. DYN.: NUMERICAL ANALYSISAssumptions
IT’S REASONABLE TO ASSUME THAT SOMETHING SIMILAR OCCURS ALSOFOR LATERAL DYNAMIC
IPG Automotive – Apply & Innovate TECH WEEKS 202047 02/09/2020
HP:
LAT. DYN.: NUMERICAL ANALYSISAssumptions
THE TIRE KEY PARAMETERS AFFECTING LATERAL DYNAMICS ARE
𝑳𝒂𝒕. 𝑹𝒆𝒍𝒂𝒙𝒂𝒕𝒊𝒐𝒏 𝑳𝒆𝒏𝒈𝒕𝒉 𝝈𝒚 𝑪𝒐𝒓𝒏𝒆𝒓𝒊𝒏𝒈 𝑺𝒕𝒊𝒇𝒇𝒏𝒆𝒔𝒔 𝑹𝒐𝒍𝒍𝒊𝒏𝒈 𝒔𝒕𝒊𝒇𝒇𝒏𝒆𝒔𝒔 𝑴𝒂𝒙 𝑳𝒂𝒕. 𝑭𝒓𝒊𝒄𝒕𝒊𝒐𝒏 𝒄𝒐𝒆𝒇𝒇.𝑲𝜶 𝑲𝝋
STEADY-STATE LATERAL DYNAMICS(steering pad)
𝝁𝒎𝒂𝒙,𝒚
IPG Automotive – Apply & Innovate TECH WEEKS 202048 02/09/2020
HP:
LAT. DYN.: NUMERICAL ANALYSISAssumptions
THE TIRE KEY PARAMETERS AFFECTING LATERAL DYNAMICS ARE
𝑳𝒂𝒕. 𝑹𝒆𝒍𝒂𝒙𝒂𝒕𝒊𝒐𝒏 𝑳𝒆𝒏𝒈𝒕𝒉 𝝈𝒚 𝑪𝒐𝒓𝒏𝒆𝒓𝒊𝒏𝒈 𝑺𝒕𝒊𝒇𝒇𝒏𝒆𝒔𝒔 𝑹𝒐𝒍𝒍𝒊𝒏𝒈 𝒔𝒕𝒊𝒇𝒇𝒏𝒆𝒔𝒔 𝑴𝒂𝒙 𝑳𝒂𝒕. 𝑭𝒓𝒊𝒄𝒕𝒊𝒐𝒏 𝒄𝒐𝒆𝒇𝒇.𝑲𝜶 𝑲𝝋 𝝁𝒎𝒂𝒙,𝒚
STEADY-STATE LATERAL DYNAMICS(steering pad)
Hypothesis: CORNERING STIFFNESS and ROLLING STIFFNESS variation could affect the increasing of the outside the curve steering torque
IPG Automotive – Apply & Innovate TECH WEEKS 202049 02/09/2020
NUMERICAL ANALYSIS:ROLLING AND THE TIRE CORNERING STIFFNESS SENSITIVITY ANALYSIS HAS BEEN PERFORMED
IPG MotorcycleMaker
LAT. DYN.: NUMERICAL ANALYSISTools
IPG Automotive – Apply & Innovate TECH WEEKS 202050 02/09/2020
SENSITIVITY ANALYSIS ON CORNERING STIFFNESS.
• Nominal value (blue)• +20% (magenta)• -20% (black)
THE CORNERING STIFFNESS COEFFICIENT SEEMS NOT TO CAUSE RELEVANT CHANGES IN STEERING TORQUE
Steering torque VS lateral acceleration.
LAT. DYN.: NUMERICAL ANALYSISResults
IPG Automotive – Apply & Innovate TECH WEEKS 202051 02/09/2020
LAT. DYN.: NUMERICAL ANALYSISResults
Steering torque VS lateral acceleration.
SENSITIVITY ANALYSIS ON ROLLING STIFFNESS.
• Nominal value (blue)• +20% (magenta)• -20% (black)
THE ROLLING STIFFNESS COEFFICIENT AFFECTS THE STEERING TORQUE: THE HIGHER THE ROLLING STIFFNESS , THE HIGHER THE OUTSIDE THE CURVE STEERING TORQUE
IPG Automotive – Apply & Innovate TECH WEEKS 202052 02/09/2020
From the numerical sensitivity analysis
LAT.DYN: Numerical Simulation
The Hypotesiysdone seems to be
correct
AS THE ROLLING STIFFNESS INCREASES, THE OUTSIDE STEERING TORQUE INCREASES
IPG Automotive – Apply & Innovate TECH WEEKS 202053 02/09/2020
From the numerical sensitivity analysis
LAT.DYN: Numerical Simulation
Why
AS THE ROLLING STIFFNESS INCREASES, THE OUTSIDE STEERING TORQUE INCREASES
IPG Automotive – Apply & Innovate TECH WEEKS 202054 02/09/2020
LAT. DYN.: NUMERICAL ANALYSISWear effect on rolling stiffness
SELF ALIGNING MOMENT
Same turn, same speed, same lateral acceleration
Nominal tyre rolling stiffness Higher tyre rolling stiffness
IPG Automotive – Apply & Innovate TECH WEEKS 202055 02/09/2020
LAT. DYN.: NUMERICAL ANALYSISWear effect on rolling stiffness
SELF ALIGNING MOMENT
𝜹
𝑭 𝒚 𝑻 𝒐 𝒕 𝒂 𝒍 𝑭 𝒚 𝑻 𝒐 𝒕 𝒂 𝒍
𝜹
𝑭 𝒚 𝑹 𝒐 𝒍 𝒍𝑭 𝒚 𝑹 𝒐 𝒍 𝒍
Nominal tyre rolling stiffness
Same turn, same speed, same lateral acceleration
Higher tyre rolling stiffness
IPG Automotive – Apply & Innovate TECH WEEKS 202056 02/09/2020
𝑭 𝒚 𝑺 𝒊 𝒅 𝒆 𝒔 𝒍 𝒊 𝒑
𝑽
𝜹
𝑭 𝒚 𝑻 𝒐 𝒕 𝒂 𝒍
𝜶
𝜶
𝜹
𝑭 𝒚 𝑻 𝒐 𝒕 𝒂 𝒍
𝑭 𝒚 𝑹 𝒐 𝒍 𝒍
𝑭 𝒚 𝑺 𝒊 𝒅 𝒆 𝒔 𝒍 𝒊 𝒑
𝑽
LAT. DYN.: NUMERICAL ANALYSISWear effect on rolling stiffness
SELF ALIGNING MOMENT
Same turn, same speed, same lateral acceleration
Higher tyre rolling stiffnessNominal tyre rolling stiffness
𝑭 𝒚 𝑹 𝒐 𝒍 𝒍
IPG Automotive – Apply & Innovate TECH WEEKS 202057 02/09/2020
𝑭 𝒚 𝑺 𝒊 𝒅 𝒆 𝒔 𝒍 𝒊 𝒑
𝑽
𝜹
𝑭 𝒚 𝑻 𝒐 𝒕 𝒂 𝒍
𝜶
𝜹
𝑭 𝒚 𝑻 𝒐 𝒕 𝒂 𝒍
𝑭 𝒚 𝑹 𝒐 𝒍 𝒍
𝑭 𝒚 𝑺 𝒊 𝒅 𝒆 𝒔 𝒍 𝒊 𝒑
LAT. DYN.: NUMERICAL ANALYSISWear effect on rolling stiffness
SELF ALIGNING MOMENT
Moment Mz actsOUSTSIDE of the curve
Moment Mz acts INSIDE of the curve
𝑴 𝒛𝑴 𝒛
Same turn, same speed, same lateral acceleration
Higher tyre rolling stiffnessNominal tyre rolling stiffness
𝜶
𝑭 𝒚 𝑹 𝒐 𝒍 𝒍
𝑽
IPG Automotive – Apply & Innovate TECH WEEKS 202058 02/09/2020
WEAR → HIGHER TIRE ROLLING STIFNESS →HIGHER OUTSIDE THE CURVE STEERING TORQUE DEMAND NEEDED TO MAINTAIN TRAJECTORY
LAT. DYN.Summary
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LAT. DYN.: OUTDOOR TESTTest scenario
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OUTLINE
1. INSTRUMENTATION (OUTDOOR TESTS)
2. LONGITUDINAL: OUTDOOR TESTS
3. LONGITUDINAL: INDOOR TESTS
4. LONGITUDINAL: MAGIC FORMULAE MODIFICATION
5. LATERAL: OUTDOOR TESTS
6. LATERAL: SENSITIVITY ANLYSIS THROUGH NUMERICAL SIMULATION
7. CONCLUSIONS
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aGENERAL TARGET:
TO INVESTIGATE THE EFFECTS OF TIRE WEAR ON BOTH THE LATERAL AND THE LONGITUDINAL
DYNAMIC; TO PROPOSE A PACEJKA MF MODIFICATION, INCLUDING THE WEAR DEPENDENCY
CONCLUSIONS:
• Increase of wear → increase of tire stiffness, maximum grip, relaxation length
• MF modification has been proposed for longitudinal tire behavior
• Outdoor tests procedure can be used to overcome the lack of the indoor tests and proceed
with tire parameter identification, for longitudinal dynamic only
• It has been demonstrated how, both experimentally and numerically, the steering torque is
strongly affected by tire rolling stiffness (the higher the stiffness, the more the outside-the-
curve steering torque)
CONCLUSIONS
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