May 17, 2022

Automated Photogrammetry – VAR of Vehicle Production – Metrology and Quality News

In football, a centimeter can be the difference between a goal on the scoreboard or an offside signal. With the introduction of the Video Assistant Referee (VAR), it is now possible to improve the level of precision when it comes to analyzing those centimeters of legality. And if instead of centimeters, we were talking about tenths of millimeters, the equivalent of the thickness of a sheet of paper?

The SEAT Measurement Technology and Meisterbock department takes care of this by measuring the bodywork of the cars. Until now, this process was done semi-manually. However, an innovative contactless technology has arrived which marks a turning point in the efficiency of the process once the car reaches the production line.

The path to precision

“Photogrammetry is a non-contact optical measurement technology that allows us to capture millions of points of an object through photos, marking the depth and thickness of each space” explains Pedro Vallejo, Head of Measurement Technology and Meisterbock at SEAT. “The collected points are captured on a colored map which indicates if there are any deviations from the norm. “In the image, we can see 100% of the vehicle’s geometric lines, both inside and out, which ensures that any changes are immediately detected” adds Paco Triguero, Head of Internal Parts Measurement at SEAT.

Sets of parts are randomly selected from the assembly line to be carefully checked during each production shift. AGVs (Automatic Guided Robots) transport these components to the measuring facilities. There, 1,500 square meter machines, equipped with cameras, begin work to ensure that all vehicles coming off the production line have the correct dimensions. In this way, safety and performance are certified and any deviations can be quickly recalibrated.

Sets of parts are randomly selected from the assembly line to be carefully checked during each production shift

Importance of adding points

A body is the sum of its various assembled parts. That is why its measurements must be exact and precise, and photogrammetry now ensures that this is the case. In total, the machines take between 200 and 300 photos per assembly and 1,000 of the entire skeleton, which is equivalent to measuring seven million points per assembly and up to 98 million of an entire chassis,” explains Paco. That’s 9,000 photos and up to 210 million points analyzed per day.

no wasted time.

Optical technology has saved up to 90% of measurement time compared to conventional touch measurements. “Before, we measured three pieces a day, whereas now we inspect 30 a day” said Paco. “It has allowed us to profoundly transform the way we have worked for 20 or 30 years, and we have trained workers in more skilled techniques, and exponentially increased the information that we obtain so that the customer receives the best possible auto” Pedro said. This technique is currently reproduced on the assembly line of the SEAT Leon and the CUPRA Formentor.

A technological milestone

The use of photogrammetry in serial measurement, adapted by and for SEAT, is a pioneering and innovative process in the industry and represents an improvement in the efficiency of measurement on the line in terms of speed, accuracy and of connectivity. “We are the first manufacturer to deploy automated, continuous and non-contact measurements on a large scale and we have succeeded in ensuring that a car coming off the line has the same level throughout the life of the series, as a prototype perfect” Peter points out.

Optical technology saved up to 90% of measurement time compared to conventional touch measurement

Projecting the future

Thanks to tools such as Big Data and Data Science, the large volume of information now obtained with photogrammetry will be used in the future to detect situations in production before they even occur. “We store all this data so that a machine learning algorithm can examine the frequency of any deviations” Pedro explains. “Now we are able to locate them and react, but later a program will act proactively: it will analyze their repetition frequency and make predictions to recalibrate the machine that produced the deviation” concludes the engineer.