Advancing the State-of-the-Art in Tire Testing
The Tire SocietySeptember 21, 2010
Camber Ridge, LLC
Dr. James F. Cuttino, [email protected]
www.camberridge.com704-575-1688
Camber Ridge, LLC
Agenda
• Motivation for Examining Current Capabilities
• Lab-Based Tire Testing• On-Road Tire Testing• Pros and Cons• A Design Proposal• Conclusions
MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN 2
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Motivation• FMVSS 126 Protocol for Electronic Stability Control
• 100% Compliance by September, 2011
• Current development relies heavily on prototype testing on proving grounds
• Each prototype vehicle = $500,000 (passenger car)
• 50 - 100 prototypes to production
• NCAP Rollover Protocols• Similar developmental costs
• In summary, need to simulate extreme maneuvers • Requires dynamic inputs in slip angle, loads, camber
• Simulations rely on projected curves and extrapolation
3MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Motivation• Heavy Truck Industry
– Few facilities can handle size / highloads (10,000 - 15,000 lbs normal)
– High torque requirements
– Durability testing
– Tire harmonics
– Rolling Resistance / Fuel Economy
– Pending regulations for electronic stability control
– Impact of customer-specified options (including tires) on vehicle compliance with regulations
– New regulations for stopping distance
4MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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In-Lab Testing Systems
Akron Standard (early 1900’s)
5MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Subtleties of Design
Freudenmann, T., Unrau, H.-J., and El-Haji, M., ‘‘Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements,’’ Tire Science and Technology, TSTCA, Vol. 37, No. 4, October – December 2009, pp. 254-278.
• Care required not to introduce parasitic errors
6MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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In-lab Testing SystemsPrüfstand für Fahrzeug/Fahrbahn
Federal High- way Research Institute (BASt), Germany
7MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
Bristol (concrete)Atlanta
Camber Ridge, LLC
Modeling the Surface(Samples from Race Tracks in the US)
TalledegaDarlington Texas
Concord
80 Grit Sandpaper
8MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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On-road Testing Systems
9MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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GM Tire Cornering Test Vehicle
Cortese, A.D., and C.S. Rockafellow, “General Motors Proving Ground Tire Cornering Test Vehicle”, SAE Transactions, 1971-02-01, Paper 710092
Correction Wheel5th Wheel
Sensor
Correction Wheel
Test Wheel
Test Wheel
10MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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On-road Testing Systems
1972 - Michelin PLR
Citroën components, two small-block Chevrolet 350 V-8s, one to drive test tire, other to power the vehicle.
11MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Current In-lab Systems• Pro’s
– Controlled environment– Good Repeatability– Historical Data Pool– Industry Standard– 24-7 Operation
• Con’s– Simulated road surface - concerns on accuracy – Load limits, depending on application– Torque magnitude and control– Limits on wet traction studies, etc.
12MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Comparison of Belt vs. Asphalt
Increasing Slip
M. G. Pottinger, G. A. Tapia, C. B. Winkler, and W. Pelz, "A Straight-Line Braking Test for Heavy Duty Truck Tires," Paper No. 45, ACS Rubber Division, Cleveland, OH, 10/17-20/95, published in Rubber World, Vol. 214, No. 6, September 1996, pp. 29-36.
13MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Comparisons of 2 Belt Coatings
M. G. Pottinger, G. A. Tapia, C. B. Winkler, and W. Pelz, "A Straight-Line Braking Test for Heavy Duty Truck Tires," Paper No. 45, ACS Rubber Division, Cleveland, OH, 10/17-20/95, published in Rubber World, Vol. 214, No. 6, September 1996, pp. 29-36.
14MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Belt vs. On-road Results
M. G. Pottinger, G. A. Tapia, C. B. Winkler, and W. Pelz, "A Straight-Line Braking Test for Heavy Duty Truck Tires," Paper No. 45, ACS Rubber Division, Cleveland, OH, 10/17-20/95, published in Rubber World, Vol. 214, No. 6, September 1996, pp. 29-36.
Belt Machine On-road Trailer
15MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Comparison of 3 Common Lab Configurations
Freudenmann, T., Unrau, H.-J., and El-Haji, M., ‘‘Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements,’’ Tire Science and Technology, TSTCA, Vol. 37, No. 4, October – December 2009, pp. 254-278.
MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN 16MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Rolling ResistanceFlat Hydrodynamic Bearing, 1.71 m Drum, 2.0 m Drum
Freudenmann, T., Unrau, H.-J., and El-Haji, M., ‘‘Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements,’’ Tire Science and Technology, TSTCA, Vol. 37, No. 4, October – December 2009, pp. 254-278.
Discrepancy largest for 2.0 m drum
17MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Current On-road Systems• Pro’s
– Realistic operating conditions – Ability to study affects such as temperature– Control over surface and profiling (asphalt,
concrete, cleats, etc.)– Wet traction, snow, other
• Con’s– Repeatability dependent on ability to control
environment– Compliance of system limits loads– Metrology frame coupled with load frame– Dependence on driver variability– Limited throughput
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Braking Results vs. Track Location
Treichel and Drahne, Tire Tests with a New Tracking System for Passenger Cars, SAE 880581, 1988.
Uncontrolled Braking Position
Braking Position Controlled
19MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Effect of Temperature on Braking Performance
Treichel and Drahne, Tire Tests with a New Tracking System for Passenger Cars, SAE 880581, 1988.
Increasing Temp
20MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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Opportunities for Improvement
• Limitations to existing technologies:– Generally limited to quasi-static testing conditions– Limited load ranges, particularly for belt machines – Limited torque applications in
driving / braking– Generally simulated surfaces (drums,
belts, abrasive surfaces)– Often restricted to lower speeds – Open loop operation forces
dependence on carpet plots and lookup tables for dynamic simulations
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Opportunities for Improvement
• Opportunities to advance state-of-the-art– More realistic interface– Wet traction, off-road (military), etc.– Dynamic input– High torque braking (heavy truck, aircraft)– ABS braking / system analysis– Long distance wear studies– Rolling Resistance– Drift and Pull– Hardware in the Loop Capabilities
22MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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“Ideal” Design Approach
• Contact Interface rules - protect at all costs.• Simplify design as much as possible.• Separate load loops from metrology loops
where possible and appropriate.• Consider modularity, flexibility.• Control environment while providing
variability.• Minimize special order components.
23MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN
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“Ideal” Design Approach
– Accuracy vs. Repeatability• Each has its place
– Resolution / Sensitivity• High loads and torques vs.
Rolling resistance, drift and pull, uniformity
– Constraints and actuation• Force Inputs - downforce, torque, Fx, etc.• Displacement Inputs - Yaw Angle, Camber
Angle, Steer Angle– Rigid constraints critical for controlled,
displacement based inputs
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Conclusion
• Tire Testing has advanced significantly over the years
• Advances have been incremental, following two fairly distinctive paths
• Understanding the history of tire testing provides a strong foundation for developing the next generation of testing capabilities
• Next meeting of the Camber Ridge Consortium is in late October
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Camber Ridge, LLC
Camber Ridge, LLC
Camber Ridge, LLC