How to float on cloud nine

This is why we develop electronic shock absorbers for autonomous driving

Bumps, concrete joints, potholes: These can become a nightmare for those riding in a car. They definitely have an adverse effect on driving comfort. This is where our shock absorbers come into play and in future autonomous cars without drivers, the demands on them will be particularly high. In order to prevent travel sickness but also for driving safety reasons, the bodywork must be as insensitive as possible to vibrational excitations. In this scenario, a conventional shock absorber reacts only to the impacts which the road provides to it. However, what would happen if our shock absorbers could do their work in advance? If they could see when a bump in the road is approaching and they can use their shock absorbing force precisely? If they knew how quickly and at what angle a curve would be taken? This is where our colleague Andreas Rohde comes into play. He leads the Innovation and Technology Department at our company, thyssenkrupp Bilstein.

With his team, Rohde is researching, on the one hand, about transferring the shock absorbing effect even more precisely onto the wheels. On the other hand, he wants to filter the great amount of data that a travelling car delivers every second so efficiently that the vehicle control sends the right commands to the shock absorbers at the correct point in time. Our current state of technology is represented by the so-called semi-active shock absorbers. Thanks to highly developed software, they are able to convert in milliseconds the data that the sensors collect from the vehicle. thyssenkrupp Bilstein’s high-end system is called DampTronic sky®.

In this shock absorber solution, two valves are installed on each of the four shock absorbers, which can adjust the shock absorption effect in a continuously variable manner. One regulates the shock absorber during extension (rebound stage), the other during compression (bump stage). The optimum shock absorption is achieved for each individual wheel at any point in time. “For example, if you are driving with the front tires over a speed hump, this information is recorded and processed together with the speed of the vehicle, the height and width of the hump,” explains Rohde. The shock absorbers of the rear wheels could then react precisely via the two valves, first in the bump stage, then in the rebound phase.

A real challenge for us is the processing of driving and vehicle data. Andreas Rohde says: “We are constantly researching to improve our algorithms so they can fish out the relevant information from the millions of items of information relevant to the shock absorption of the car as quickly as possible.” In addition, Rohde and his team are trying to figure out which forces and accelerations affect the body when driving and, together with other perceptions of the senses, foster travel sickness. Our ideal goal would be that the occupants of vehicles felt neither bumps, nor the taking of curves, nor braking and accelerating. And maybe a car trip with our assistance might seem as quiet as the journey on the train.