Case Study I Heavy Duty Truck

Transcription

AUTOMOTIVE RESEARCH CENTER
Case Study I
Heavy Duty Truck M916A1/M870A2
Jeff Stein
Dennis Assanis
ARC Conference
arc
June 3 & 4, 1997
Ann Arbor, Michigan
M916 - CASE STUDY
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Objectives
• To develop 1st generation models and simulation tools for
a complete vehicle:
- Powertrain and Vehicle Dynamics for vehicle mobility simulation
• To demonstrate for the M916 truck:
- Proper handling models
- Steering/braking for rollover
- Truck acceleration on flat road
- Traction while hill climbing
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M916 - CASE STUDY
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Why Select the M916 Tractor Semitrailer
as an Exemplar?
• Represents an important class of “real-world” vehicle
modeling issues
• The DDC Series 60 engine has been extensively
simulated and tested at the University of Michigan
• Trailer parameters have been previously measured at
UMTRI and other vehicle parameters were available
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M916 - CASE STUDY
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Challenges
• Test new methodologies with large,
“real-world” models
• Integrate multiple ARC research projects
• Integrate Matlab-based Powertrain models with
large nonlinear Vehicle Dynamics models
• Produce source code for equations of motion
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M916 - CASE STUDY
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Software Environments
• ArcSim: Vehicle Dynamics
• PowerSim: Powertrain & Vehicle Dynamics
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ArcSim: Features
• A user friendly and flexible Vehicle Dynamics simulation
and animation environment
• Software architecture based on commercial TruckSim
software
• Source code for models generated with commercial
AutoSim software
• Available on the WEB:
- http://arc.engin.umich.edu/arc/research/T1.html
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M916 - CASE STUDY
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ArcSim User Interface: Top-Level
Post-Processing
Programs
Start Screen
Animator
Runs Screen:
Simulation Setup
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Inputs
X-Y Plotter
Vehicle Data Sets
Simulation Codes
(models)
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ArcSim User Interface: Vehicle Data Sets
Vehicle Data Sets
Tractor
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Suspension
Tire Data Sets
Trailer
Steering System
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ArcSim User Interface: Tire Data Sets
Tire Data Sets
Longitudinal Force
(Fx) Data
Lateral Force
(Fy) Data
Aligning Moment
(Mz) Data
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M916 - CASE STUDY
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Proper Tire Models
Tire data sets generated from numerical experiments
using proper tire model
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PowerSim: Features
• A flexible Powertrain and Vehicle Dynamics simulation
• Matlab-Simulink based simulation environment developed
by the University of Wisconsin team:
- Hierarchical
- Interactive
- Choice of sub-models
- Easily reconfigurable
• High fidelity, transient diesel engine model developed and
validated by the University of Michigan team
• Diesel engine simulation available on the WEB:
- http://arc.engin.umich.edu/esim-docs/esim.html
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M916 - CASE STUDY
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ArcSim - PowerSim Integration
PowerSim
Vehicle Dynamics &
DriveTrain Block
ArcSim
C-Mex code for vehicle
dynamics models
Post-Processing Programs
X-Y Plotter
Animator
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M916 - CASE STUDY
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M916 Vehicle Specifications
• 21 rigid body DOF / 91 state variables
• 126,000 lbf GVW
-M916A1 3-Axle Tractor (6x6)
-M870A2 3-Axle Semitrailer
• Thermodynamic simulation with
physically based sub-models
• DDC Series 60 engine
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-475 HP@2100 rpm
-Turbocharged, intercooled
M916 - CASE STUDY
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M916 Model Characteristics
• 21 rigid body DOF / 91 state variables
- Tractor: 6 DOF
- Trailer: 3 DOF (Rotational)
- Axles: 2 DOF (Roll and Jounce)
- Wheels: 1 DOF (Spin)
- 25 auxiliary states
• Computational load
- 6600 multiplies/divides, 6000 add/subtracts per evaluation
of state derivatives
- Runs at about 3.5 sec computation time per sec of
simulated motion on a 120 MHz Pentium
• Parameters obtained by measurement or estimation
• Modeling assumptions verified
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M916 - CASE STUDY
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M916 Example Applications
I. Proper handling models
II. Steering/braking for rollover
III. Truck acceleration on flat road
IV. Traction while hill climbing
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Example Application I
Proper Handling Models
Runs Screen
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Programs Based on Different
Equaton Formulations
Programs Based on Different
Complexity Models
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Element Importance
High
Low
Idea: Use power-based metric to rank the
importance of components and eliminate
low-importance components
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M916 - CASE STUDY
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Handling Performance Predictions
Full Model vs. Reduced Model
0.2
0.1
Tractor Lateral Acceleration [g’s]
0
-0.1
-0.2
0
1
2
3
4
5
Time [sec]
6
7
8
9
10
1
2
3
4
5
Time [sec]
6
7
8
9
10
5
Tractor Yaw Rate [deg/s]
0
-5
arc
0
Full
Reduced: 30% of elements removed
M916 - CASE STUDY
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Example Application II
Steering/Braking for Rollover
Post-Processing
Programs
Start Screen
Animator
Runs Screen:
Simulation Setup
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Inputs
X-Y Plotter
Vehicle Data Sets
Simulation Codes
(models)
M916 - CASE STUDY
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UMTRI “Drastic” Maneuver
Brake pressure is switched on and off when roll rate is zero
100
Steering wheel angle [deg] 50
0
0
1
2
0
1
2
0
1
2
Time [sec]
3
4
5
3
4
5
3
4
5
20
Brake pressure [psi]
10
0
2
Trailer roll angle [deg] 1
0
-1
arc
Time [sec]
Time [sec]
M916 - CASE STUDY
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Worst-Case Steering/Braking
Conditions for Inducement Rollover
Steering wheel angle [deg]
Brake pressure [psi]
25
Trailer roll angle [deg]
90
100
80
20
70
50
60
15
50
10
0
40
30
5
-50
20
0
10
-100
0
0
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worst-case
Time [sec]
5
-5
0
Time [sec]
5
drastic
0
Time [sec]
5
Idea: To use optimal control/zero sum game theory, to
systematically identify worst case input conditions and
compare to conventionally chosen “drastic” inputs
M916 - CASE STUDY
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Mobility Studies
Air
TURBINE
COMPRESSOR
Diesel Engine
System
INTERCOOLER
WASTEGATE
PowerSim
FUEL
SYSTEM
Exhaust
gas
Fuel
INTAKE
MANIFOLD
MULTI-CYLINDER
DIESEL
ENGINE
EXHAUST
MANIFOLD
.
W
Driveline
AAA
AA
AAA
AAAA
AAAAA
AAA
AA AA AA
AA
AA AA
TC
AA
AA
AA
AA
AA
AAA
AA
AA
AAA
AAAAAA
AA
AAAA
AA
AAA
AAAAAA
AAAAAA
AA
AAA
AA
AA
AAA
AA
AA
AAA
AAAAA
AAAAA
AA
AAA
AA
D-F
Trns
IA-D
Point
Mass
126,000 lbf
GVW
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Vehicle
Dynamics
Tr-C
D-FR
D-R
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TC Diesel Engine System Simulation
Flexible Powertrain Simulation
developed in SIMULINK by the
University of Wisconsin team:
-
Hierarchical
Interactive
Choice of Sub-models
Easily Reconfigurable
TC
IC
Ex
mnfld
Engine
In
mnfld
Cylinders
The in-cylinder model: UM - UW - WSU
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M916 - CASE STUDY
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FUEL &
COMBUSTION
DRIVETRAIN
HEAT
TRANSFER
ENGINE
FRICTION
IN-CYLINDER
DIESEL
ENGINE
MODEL
EXTERNAL
SUBSYSTEMS
ENGINE
VIBRATION
TRANSIENT
COLD START
TURBOCHARGED DIESEL
ENGINE SYSTEM
INTEGRATION WITH THE VEHICLE SIMULATION
Advanced Propulsion System Simulation
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M916 - CASE STUDY
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Experimental Set-Up for Model Validation
Pressure Transducers / Heat Flux Probes in all Cylinders
6 cylinder
turbocharged
diesel ENGINE
DYNAMOMETER
PRESSURES
TEMPERAT.
VIBRATIONS
DYNO
CONTROL UNIT
LOW SPEED
DATA ACQUISITION
& CONTROL SYSTEM
• VXIbus Technology
• MXI PC interface
• VXIplug&play Instruments
•
•
•
•
120 channels, 16 bit A/D
12 channels D/A
48 channels D/D
20 relay outputs
SPEED
TORQUE
FLOWS
CYCLE &
TIME
RESOLVED
EXHAUST
GAS
ANALYSIS
HIGH SPEED
DATA ACQUISITION
SYSTEM
• VXIbus Technology
• Embedded VXIpc - 486
• VXIplug&play Instruments
•
•
•
32 channels, 16 bit
simultaneous A/D
4 Mb mass storage device
1 GB SCSI HD
Three-Component Force Transducer
for Engine Vibrations Studies
The Engine: DDC-60 Six-Cylinder, Turbocharged, Intercooled, Direct Injection Diesel
Engine Geometry: B = 13 cm; S= 16 cm; L = 26.93 cm; CR = 15
Rated Power = 350 kW @ 2100 rpm
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M916 - CASE STUDY
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Calibration and Validation of Sub-Models
Model constants calibrated
to produce best agreement
between measured and
predicted pressure traces
Same set of calibrated
constants used for all other
operating points
RATED SPEED,
FULL LOAD
CALIBRATED
POINT
100
1200 rpm
50% load
CYLINDER PRESSURE (bar)
CYLINDER PRESSURE (bar)
120
150
80
100
60
40
experiment
simulation
20
0
320
2100 rpm
100% load
340
360
380
400
CRANK ANGLE (deg)
420
50
0
320
experiment
simulation
340
360
380
400
CRANK ANGLE (deg)
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M916 - CASE STUDY
420
26
Transient Engine Model Validation
2500
ENGINE SPEED - MEASURED
2000
ENGINE SPEED - PREDICTED
1500
EXTERNAL
LOAD
1000
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400
350
300
250
BOOST
PRESSURE
200
150
500
0
450
Intake Manifold Pressure (KPa)
Engine Speed (rpm); External Load (Nm)
A sequence of elementary transients defined in order to validate
predictions of the multi-cylinder engine response against experimental
measurements under carefully-controlled test-cell conditions.
100
0
5
10
15
Time (s)
20
25
50
30
M916 - CASE STUDY
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Example Application III
Truck Acceleration on Flat Road
Study the Effect of Turbocharger Inertia on Engine
Response and Vehicle Acceleration
126,000 lbf
GVW
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•Start at 10 mph
•100% driver demand
M916 - CASE STUDY
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Connection Points
for Model Integration Methodology
126,000 lbf
GVW
Point
Mass
Engine
Vehicle
Dynamics
Driveline
Engine Load Torque
Rigid
Crankshaft
Engine
Angular
Speed
Torque Converter
& Transmission
ω
τ
Wheel
Drive
Torques
Flexible
Axle Shafts
Wheel Hub Inertias
& Tire Model
Wheel Angular Speeds
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PowerSim
M916 - CASE STUDY
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Performance Comparison
1900
1800
1700
ENGINE 1600
SPEED
(rpm) 1500
M916A1 SEMI
Gross Curb Weight 126,000 lb
First Gear
Low Inertia TC
TURBO
LAG
High
Inertia
TC
1400
1300
ITC LI = 0.5 ITC HI
1200
0
28
26
24
TRUCK
SPEED
(mph)
2
TURBO
LAG
4
6
8
10
M916A1 SEMI
First Gear
Low Inertia TC
22
20
High Inertia TC
18
16
14
12
arc
10
0
2
4
6
TIME (s)
8
10
M916 - CASE STUDY
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Example Application IV
Traction While Hill Climbing
126,000 lbf
GVW
Fz
Axle 1
5%
Grade
Fz
Fz
Axle 6 Axle 5
Fz
Axle 4
Fz
Axle 2
Wet Surface
µ = 0.4
Fz
Axle 3
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•10 mph
•100% driver demand
Idea: Show how thrust and terrain
inclination dynamically affect wheel
loads and thus traction
M916 - CASE STUDY
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Connection Points for Model
Integration Methodology
126,000 lbf
GVW
Point
Mass
Engine
Vehicle
Dynamics
Driveline
Engine Load Torque
Rigid
Crankshaft
Engine
Angular
Speed
Torque Converter
& Transmission
ω
τ
Wheel
Drive
Torques
Flexible
Axle Shafts
Wheel Hub Inertias
& Tire Model
Wheel Angular Speeds
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PowerSim
M916 - CASE STUDY
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Vehicle Dynamic Models
Point-mass model
• 1-D point mass
• Constant vertical tire loads
• Tire Fx independent of Fz
• Constant road slope
• Simple rolling resistance model
• Simple aero drag model
Multi-body model
• 21 Rigid Body DOF
• Full nonlinear kinematics
• Comprehensive tire model
• Hysteretic suspension springs
• Comprehensive steering model
• Simple braking model
• Constant road slope
• Simple rolling resistance model
• Simple aero drag model
• Bottom Line: The interaction
arc
of pitch and handling
dynamics with the engine and
Powertrain can be studied.
M916 - CASE STUDY
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Hill Climbing: Results
0.15
22
M916A1 SEMI, Gross Curb Weight 126,000 lb
20
ax
0.1
18
VEHICLE
SPEED [mph]
0.05
16
14
VEHICLE
ACCELERATION [g's]
vx
0
12
-0.05
10
8
0
2
4
6
8
-0.1
10
TIME [sec]
arc
M916 - CASE STUDY
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Hill Climbing: Results - cont.
REAR
15
FRONT REAR
WHEEL VERTICAL
LOAD [lb*1000]
10
5
FRONT
0
2
M916A1 SEMI
4
6
8
10
TIME [sec]
arc
M916 - CASE STUDY
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Hill Climbing: Results - cont.
5000
M916A1 SEMI
4000
REAR
3000
WHEEL LONGITUDINAL
FORCE [lb]
2000
1000
FRONT
0
FRONT
WHEELS
SLIPPING
-1000
0
2
4
6
8
10
2.8
2.6
REAR
FRONT
2.4
2.2
WHEEL SPEED [rev/s]
2
1.8
1.6
1.4
arc
1.2
M916A1 SEMI
0
2
4
6
8
10
TIME [sec]
M916 - CASE STUDY
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Summary
• Demonstration 1st generation models and simulation tools
of a complete vehicle:
- Powertrain
- Vehicle Dynamics
• ArcSim and PowerSim:
- User friendly and flexible Vehicle Dynamics and Powertrain
simulation and animation environments
• Demonstrated with the M916 truck:
- Handling (multiple models)
- Rollover (limit maneuvers)
- Mobility studies
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M916 - CASE STUDY
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Future Directions
• Vehicle
- Survivability: Battle field performance
- Drivability: Handling and acceleration
- Mobility: Dynamic and wheel traction
- Efficiency: Terrain roughness and fuel economy
- Safety: Limiting maneuvers
• Model refinement and validation
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M916 - CASE STUDY
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Case Study I Heavy Duty Truck

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