Scanning at la Sarthe

3D scanning system keeps competitors honest.

An old NASCAR saying is “If you ain’t cheatin’, you ain’t tryin’,” and while the 24 Hours of Le Mans is, perhaps, more sophisticated, the race organizer, the Automobile Club de l’Ouest (ACO), has to assure that the 60 or so cars in the field meet the specs, without, well, bending the rules.

According to Guillaume Bouttier, Technical Delegate of ACO, 30 to 35 cars are usually assessed in a day, which gives ACO inspectors approximately 10 minutes per car.

Until recently, the scrutineering process depended upon manually scanning the cars with single-point lasers; measurements could vary according to the operator using the device. ACO wanted to improve its level of quality control, Bouttier says, so the organization decided to work with Creaform (creaform3d.com) to develop a new inspection system based around 3D scanning.

The result combines a MetraSCAN 750 3D scanning system with a customized scrutineering plug-in for the Creaform PolyWorks inspection software, and a custom-built platform.

Inspection requires the measurement of a vehicle’s weight and reference plane (the clearance underneath the car), as well as its dimensions. The solution’s platform includes Captels scales that automatically weigh the car and four Ametek Solartron linear measurement lasers to measure the reference plane. It also features a metal structure that facilitates easy, precise movement of the optical tracker.

After a car is weighed and its reference plane measured, the operator places positioning artifacts on the vehicle, which enables dynamic tracking with the system’s C-Track optical tracker. The software guides the operators in manually placing the tracker to each of the seven positions needed for scanning separate sections of the car. At each position, the targets of the positioning artifacts are detected automatically, and the specific sections are scanned and inspected by the operator.

The hand-held MetraSCAN 750 scanner’s handle is surrounded by reflectors used by the C-Track to precisely locate the position of the scanner in space. The tracker enables dynamic referencing, automatic alignment and continuous monitoring of part parameters, which for ACO means their inspectors can do their job in less-than-ideal environments such as the track or shop floors without having the measurements compromised.

The MetraSCAN uses laser-triangulation 3D scanning technology that takes about 480,000 measurements per second, which enables ACO to meet its needed inspection time of 10 minutes per car. It can scan surfaces of varying colors and shininess equally well, according to Bouttier: “You have prototypes, you have GT cars. The shapes are different, colors are different and for us, we really appreciate that the Creaform 3D system is able to read anything.”

While inspecting, “we can compare each part of a car to a CAD file, which is really new for us,” Bouttier says. At the end of each of the seven scanning sequences, data is automatically extracted for each element and a full-scale report is generated and can be printed and shared immediately with the car’s racing team. —M.A.

 

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The Creaform MetraSCAN 750 3D scanner checks the dimensions of a wheel assembly on a 24 Hours of Le Mans entry.

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The C-Track optical tracker is positioned on a moveable gantry-like structure.