Chassis inspection system a state-of-the-art process

It consists of a seven-axis Romer articulating arm ...

It consists of a seven-axis Romer articulating arm ...

... a steel platform with drill holes placed in a unique pattern ...

... a steel platform with drill holes placed in a unique pattern ...

... the ball probe is touched to three of the drill holes.

... the ball probe is touched to three of the drill holes.

Introduced in 2007, NASCAR's new car defines the objectives of "safety, competition and cost management." And the state-of-the-art chassis certification process goes hand-in-hand with those goals.

And that's accomplished with the help of two sophisticated portable coordinate measuring machines, located at NASCAR's R&D Center.

NASCAR officials require every Sprint Cup chassis to be certified for competition -- and in the event of an accident, it must be re-certified before getting the go-ahead to be used again. With the new car, that demanded an advanced chassis certification and inspection process, one that allows NASCAR to identify and keep records on each unique chassis, provide accurate measurements to within one-ten-thousandths of an inch and improve tolerances.

The system, developed by Romer Inc. of Michigan, works on the idea of creating a three-dimensional data representation of each chassis in order to compare it with NASCAR's rules. It consists of a seven-axis Romer articulating arm, a steel platform with drill holes placed in a unique pattern and certified by laser, and software provided by Delcam plc.

The chassis to be inspected is rolled onto the platform and locked into place. Once the measuring arm is activated and the ball probe is touched to three of the drill holes, the monitoring device automatically can identify its specific position on the grid and accurately determine the x, y and z coordinates for any location on the chassis to be certified.

The NASCAR technician can inspect more than 220 specific locations on the chassis using the articulating arm, which can be moved around the platform as needed. All the technician has to do is reset the arm's specific position -- and begin inspection. A large plasma screen on the wall provides the technician with immediate interaction and guarantees the consistency of each inspection.

In addition to checking the chassis for adherence to height and width, the technicians use an ultrasound probe to check sheet-metal thickness.

Each certified chassis is out-filled with 10 radio frequency identification microchips, which are placed in specific locations. They are about the size of a quarter -- made of a white plastic material, sticky on one side, with a tiny black chip and two copper wires that lead to the antenna. The RFID chips are attached to the metal and usually then covered by tape in order to protect them from accidental damage and possible tampering.

In addition, a unique serial number that matches the RFID chips is placed on an interior roll bar of the chassis, much like the vehicle identification number for a passenger vehicle.

With a handheld reader, NASCAR inspectors at the track can check the RFID chips to quickly and precisely determine the current status and history of each chassis, making sure only certified chassis are permitted to compete.

Once the inspection is complete, a spreadsheet document is generated that shows the measurements taken and their relation to the tolerances allowed, and lists any locations where the chassis may have exceeded tolerances.

The entire process takes less than two hours, and is provided to the teams at no cost. Managing director Mike Fisher said more than 2,000 chassis have been certified or re-certified since the end of the 2006 season, with a 90 percent success rate.

By Mark Aumann,