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An agreement between the U.S. Army Aberdeen Test Center (ATC) and the Department of Mechanical Engineering will one day offer exposure to engineering students interested in vehicle dynamics, powertrain performance and vibration testing in a practical lab environment.
Dr. Greg Schultz, ME alumnus and lecturer, has been working at the Aberdeen Proving Grounds in Maryland since 1988, and has been developing an advanced Roadway Simulator at the ATC since 1994. The simulator tests the performance of vehicles ranging from 5,000 pound, 2-axle light trucks to 80,000 pound tractor trailers. The simulator will be available for student research within the year, catering to mechanical, electrical and reliability engineering students interested in vehicle dynamics and test engineering. This opportunity will become part of the research efforts of the Maryland Center for Automotive Research (MCAR) at the University of Maryland.
Imagine the Roadway Simulator as system of high-tech treadmills, with each of the vehicle?s wheels resting on a treadmill. The treadmills are set below floor level in a pit, supported by some of the largest hydraulic supports on the East Coast. A vehicle is ?driven? on the treadmills by a set of robotic actuators without the need for a driver or large test track. The vehicle?s performance is monitored by instrumentation that records how the vehicle handles on a simulated roadway. The vehicle is constrained at its center of gravity with a restraint bar, and is put through vertical, cornering and traction tests to determine how it handles in predetermined situations.
The simulator can be operated in on two control modes ? road load and road speed. The principle of its operation is based on satisfying Newton?s laws of motion, or F = M a. The simulator reacts kinematically to forces exerted by the truck. In other words, the truck drives on the simulator instead of over a road.
?The Roadway Simulator is the largest automotive simulator for vehicle dynamics in the world,? says Dr. Schultz, who obtained his Ph.D. from Maryland in 2002. ?It will offer engineering students practical, real-life experience in automotive testing which is not always available to engineering students at other universities.? Dr. Schultz teaches the ENME 489V Vehicle Dynamics course, and is the advisor for the Formula One SAE racing team and mini Mini baja Baja vehicle project, which are part of the ENME 408 course.
The One of the biggest benefit s of the simulator is test repeatability, which can?t always be done achieved on a real road situation. Simulated wipe-outs can be observed over and over again. With a robotic arm as a driver, it is also a safer option than road testing. Vehicles can also be tested faster on the Roadway Simulator, which in the end saves money. Schultz is also working on the development of a vehicle durability simulator which should be available for testing in a few years.
Most of the vehicles currently tested on the Roadway Simulator are heavy, military-grade personnel carriers and trucks, but the simulator can also test typical economy passenger-sized vehicles as well. At present the simulator can test vehicles as heavy as thirty tons , such as trucks with tandem rear axles. With added features, at the next stage of development the simulator will be able to test tractor-trailer combination vehicles as heavy as 40 tons.
Ivan Tong, a 2002 graduate from the Mechanical Engineering Graduate program, is one of seven staff members who work with the simulator. "It has been exciting working on something that no one has done before," says Tong. When asked how working with the simulator would generally benefit a Maryland graduate, Tong responded, "The simulator offers hands-on experience and exposure to real automotive industry customers in addition to the army products."
August 15, 2004
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