Driverless, Fully Electric, Vehicle Model-Independent – Continental Redefines Tyre Braking Tests

Continental presents a new driverless and fully electric test vehicle which it has developed for measuring the braking performance of passenger car tyres. The objective of the fully automated test is to further reduce the braking distance of tyres to ensure greater road safety. The AVA – “Analytic Vehicle AIBA” – enables precise monitoring of the frictional properties of tyres during braking manoeuvres on dry and wet roads. For the first time, the Continental AVA combines the advantages of a test method which is independent of the vehicle model, with the controlled and reproducible test environment of the Automated Indoor Braking Analyzer (AIBA). Continental’s tyre testing experts can therefore perform tests regardless of vehicle specific characteristics. With this, Continental has one of the world’s most advanced and precise tyre braking test methods. The cutting edge and globally unique test vehicle is used on the company’s proving ground Contidrom near Hanover, Germany.

“Our analytic vehicle AVA helps us to analyse the performance of our premium tyres in even greater detail and systematically develop them,” explains Dr. Boris Mergell, Head of Research and Development of Continental’s Tyres group sector. Transmission of forces between the tyre and the road surface is decisive for tyre braking performance. It is equally important for cornering characteristics or when changing direction. “The performance of the tyre during braking is essential for the safety of the vehicle. For this reason, we make great efforts to analyse our tyres as precisely as possible,” emphasises Mergell.

For the tyre braking tests, the AVA is accelerated to a test speed of 18mph with the aid of an electromagnetic linear drive, which is derived from modern roller coaster technology. Then, several fully automated braking tests are carried out. The AVA drive system is equipped with two electrically driven axles, which are powered by a high-performance battery. The high torque ensures that a constant speed can be maintained, while the test tyres on the third axle can be systematically braked. The integrated braking system of the AVA is equipped with Brake-by-Wire technology from Continental’s Automotive business sector. Unlike conventional hydraulic braking systems, the braking signal is transferred electronically. The brake response is very quick and precise, which is essential for accurate testing or measuring.

“Our AVA determines the transmission of forces between the tyre and the road surface, while various slipping states, so-called “µ-slip curves”, are precisely reproducible. With the state-of-the-art measuring technology, we measure all of the forces which act between the tyre and the road surface during braking. We can compare our tyres and their various compound compositions even more precisely and optimise them for their special uses,” explains Meletis Xigakis, who is responsible for global tyre testing at Continental. The AVA is used in the Automated Indoor Braking Analyser, which began operation in 2012. Brake tests on various road surfaces are performed on the 75 metre test track. The air-conditioned area of the test hall has up to five road surfaces which can be exchanged hydraulically. In the weather-independent facility, up to 100,000 braking tests can be performed annually on dry, wet or even icy roads. The system is integrated into a 350 metre long and up to 30 metre wide hall.

In total, new Continental tyre models are run for the equivalent of 25 million kilometres per year on test beds and test tracks. This corresponds to 625 times around the world. This great effort is fully justified. It is the basis of the premium quality of Continental tyres. Together with the company test tracks in Uvalde, Texas (USA), and in Arvidsjaur, Sweden, the Contidrom in Jeversen, near Hanover, Germany, is one of the most modern proving grounds in the world. The test track near Hanover was opened in 1967 and since then has been continuously modernised to meet the increasing requirements on tyre tests.

In 2013, the Contidrom was awarded the title “Proving Ground of the Year” by the international jury of the Automotive Testing Technology International Award. It is considered to be a benchmark by many customers in the automotive industry. On a total area of 160 hectares, the proving ground provides every conceivable option for tyre testing. On a ten kilometre track with a large variety of partly water-covered road surfaces, and the legendary circuit with banked turns, speeds of more than 155 mph are achieved. In addition, there are also tracks for testing chassis elements. During 2022, an innovative dynamic driving simulator which can calculate the exact dynamic parameters of the tyres and the test vehicle involved will be commissioned at the Contidrom. This provides the professional Continental test drivers with exactly the same subjective driving feel as tyre tests on the test track.