Institute researchers develop new way to test tires

Students and a professor at the Institute for Advanced Learning and Research in Danville developed a unique way to test tires.

Associate professor Saied Taheri and Virginia Tech students in the Intelligent Transportation Lab at the Institute developed a trailer that houses equipment to test tires on actual roads and road conditions.

After a year and a half of development, the team finished validating the test trailer in August. The researchers compared the results of tests on tires to manufacturers’ own laboratory tests. The data matched.

Taheri published a paper on the test trailer at the Tire Society Conference in September. He expects to publish at the Society of Automotive Engineers in 2010.

“It works,” Taheri said. “No one else is doing it to this extent.”

Most manufacturers and researchers test tires on a flat-track “indoor treadmill.” The rolling test trailer is only one of three such systems that tests outside in the real environment, graduate student Joshua Caffee said.

The trailer helps the Intelligent Transportation Lab test for stability of vehicles or measure what conditions would cause a vehicle with specific tires to roll over, Taheri said. With that information, researchers could develop controls to better stabilize a vehicle.

The difference with using a test trailer is it gives a more realistic idea of what could happen since the tire is on an actual road, Taheri said.

“Tire information is the key,” he said. “You have to know how the car moves on the road.”

A pickup truck pulls the $250,000 trailer along a road at a speed up to 35 mph, Caffee explained. Inside the trailer, a tire travels along the road on a round Kistler dynamometer that can measure moments and forces on the tire.

A software-controlled motor can steer the tire left or right. Another motor can tilt the tire inward or outward. A Firestone air spring, located above the tire, inflates with nitrogen gas and is capable of applying up to 10,000 pounds of force.

The analyzed data is then fed into simulation software and a “hardware in the loop” system. Researchers can complete maneuvers in simulation to check for rollover of the vehicle and tire.

Students built a full upright version of a car, replete with seat, steering wheel and brakes as part of the hardware in the loop system.

They hope to eventually get an anti-lock braking system in that system verified and then installed on the tire assembly in the trailer to use in simulations, Caffee said.

Caffee and other Virginia Tech graduate students Brad Hopkins and Derek Fox along with undergraduate Bryan Sides worked on the trailer under lab director Taheri, who also teaches in the mechanical engineering department at Virginia Tech’s main campus in Blacksburg.

The Intelligent Transportation Lab is part of Virginia Tech’s Center for Vehicle Systems and Safety.