Simulation Applications in Mobility Research
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Transcript of Simulation Applications in Mobility Research
Thomas D. Gillespie, Ph.D.Research Professor Emeritus, The University of Michigan
Director of Product Planning, Mechanical Simulation Corporation
ISTVS 8th Americas Conference
Simulation Applications in Mobility
Research
Simulation Questions
� In what areas can truck simulation tools help us
understand the mechanics affecting on/off-road mobility?
� Do Performance Based Standards being developed for
on-highway trucks point the way for designing better
off/on-road vehicles?
� What are some of the new technologies for powertrain
control being developed by the automotive industries
that could potentially improve mobility of off/on-road
vehicles?
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Engineering plotter
Surface animator
Vehicle math model solversGraphical database
What Is Simulation?• Computes time-based vehicle motion
• High fidelity models
• All in one, turn key program
• Multiple examples
• Built-in animation
• Built-in plotter
• Runs in real time
Areas where simulation help us understand the mechanics affecting on/off-road mobility?
� Simulation creates a virtual vehicle for testing:
� Mobility/tractive performance – propulsion and braking
� Turning behavior – agility and maneuverability
� Rollover – static and dynamic
� Ride – crew comfort and fatigue
Examples of Mobility Simulation
Severe Bump Test Course
Rollover Threshold
Tire Forces when Maneuvering
Do Performance Based Standards being developed for on-highway trucks point the way for designing better off/on-road vehicles?
� Gradeability and turning quantify maneuvering
performance
� Startability on grades (PBS 15% slopes)
� 10x10 gradeability on slippery terrain
� Front axle friction demand when turning multi-axle
vehicles
New technologies for powertrain control from the automotive industries
� Advanced 4WD/AWD systems
� Broad class of powertrain systems
� Differences between manufacturers, models and brands
� All controls throttle and brakes automatically to increase mobility
� Crawl control
Powertrain Example -- Ford Intelligent 4WD
Ford Intelligent 4WD Features
� Normal: Default FWD with RWD as needed
� Mud/Ruts: Aggressive throttle response, limited
upshifting and de-sensitized ESC to allow more spin
� Snow/Grass/Gravel*: More responsive upshifting
with engine torque controlled for traction
� Sand*: Tuned to allow aggressive wheel spin for
traction
� Hill Descent: Sets and maintains constant speed
during hill descent
*ABS mode changes to allow material build up in front of the tire
Toyota Multi-Terrain Select System with Crawl Control
� Regulates wheel spin by control of throttle and brake
� Crawl Control
� Set speed from 1 – 5 mph
� System controls throttle and brakes, driver only steers
Example of Off-road Simulation
� Crusher is a high-mobility autonomous vehicle
� Developed by National Robotics Engineering Center, Pittsburgh PA
� 6x6 vehicle with skid steer
� Advanced high speed model was tested using TruckSim
Ref: DARPA Project, Carnegie Mellon University
National Robotics Engineering Center
End