April 28, 2009 Ahh speed bumps - the bane of any motorist’s existence. Although there is some controversy regarding the noise they make and the possible damage they can do to vehicles, there is no argument they are successful in keeping vehicle speeds down. Now researchers at Purdue University have developed another positive use for the speed bump – detecting damage to critical suspension components by simply driving over it. But this high-tech bump isn't destined for your local street.

The system developed by Purdue University's Center for Systems Integrity working with the U.S. Army and Honeywell International Inc. is not an actual speed-bump, but rather a rubber-jacketed speed bump-like device equipped with sensors called triaxial accelerometers. These sensors measure vibrations when a vehicle drives over the "tactical wheeled vehicle diagnostic cleat” and using signal processing software the system is able to detect damage in the tires, wheel bearings and suspension components.

The diagnostic cleat is not designed to replace maintenance checks, but provides a quick first check to determine what's mechanically wrong before wasting time hunting for potentially simple problems. The development team say that by using the diagnostic cleat and other "condition-based" maintenance methods, the military could reduce costs by performing work on vehicles only when they need it instead of scheduled maintenance. With operating costs for military weapon systems accounting for around 60 percent of the USD$500 billion U.S. Department of Defense budget in 2006 according to the team, even a small percentage saving will translate into substantial dollar amount.

So far the researchers have tested the system in experiments with Humvees and developed a computational model to simulate how the system works. The team found that the system is capable of accurately identifying damage to vehicle tires and was sensitive to as little as a 5 percent change in the stiffness of the suspension. A damaged coil spring in the front suspension of a Humvee was detected even when tire pressure was varied widely in attempt to confuse the system.

A a large vehicle survey exercise is planned involving vehicles coming back from overseas. This will bring in data on the types of wear and tear exhibited by vehicles deployed in certain terrains, while future research could focus on refining the signal processing software to more precisely identify specific components in the vehicle's suspension system.

The researchers have filed a patent for the system, which doesn’t require specialized training to operate, and it is relatively inexpensive, costing about USD$1,500.

The system could be used in commercial applications to test civilian vehicles, which offers up the prospect of a speed bump being used to detect the damage you did to your suspension going over a previous speed bump.

Darren Quick