See where the journey goes

The challenges of autonomous driving

December 04, 2020

Autonomous vehicles could become the cars of the future. However, they still face a number of challenges, including the increased risk of occupants suffering from travel sickness while on the road. This problem cannot be solved by optical information alone, which is fed to the passengers via displays, for example, as researchers from the Max Planck Institute for Biological Cybernetics in Tübingen have now shown.

A view through the VR-glasses.

Many car travelers have already experienced it once: While the driver steers the car unhindered over a winding country road, the fellow travelers are often overcome with an unpleasant nausea - especially when they sit in the back seat or against the direction of travel or when they stick their nose into a book while driving and therefore cannot see where the journey is going. "Travel sickness is a major challenge for the development of autonomous vehicles," says Heinrich Bülthoff, Emeritus Director at the Max Planck Institute for Biological Cybernetics in Tübingen. "When we think of closed cabins, which in the future will serve as a sort of mobile office to make good use of travel time, we have to solve this problem".

How travel sickness develops has not yet been finally clarified. According to a common theory, the cause could be a sensory conflict: The movement and the expectation of it - what we see, for example - do not match. According to this theory, it should help to provide the occupants of the vehicle with as precise information as possible about the impending movement - acceleration, curves, braking and so on. In fact, a number of studies in the past have concluded that even simple flashing signals announcing, for example, a bend, can already help to reduce the risk of travel sickness somewhat. For the team around Bülthoff therefore the question arose whether it could succeed with better visual information to solve the problem as far as possible.

Prof. Dr. Heinrich Bülthoff in front of the CyberMotion Simulator.

The researchers asked volunteers to take a seat in a driving simulator. Using virtual reality glasses, i.e. monitors attached to the head, passengers were seated in a virtual vehicle and received optical simulations of a driving route. In a refined version of the experiment, clouds of moving light spots on the sides and floor of the vehicle served to provide additional optical information about acceleration, braking and curves.

However, the result was sobering: "In our simulations we observed no relief from motion sickness," says Ksander de Winkel, first author of the study, who is now conducting research at the University of Delft. "In any case, there was no positive effect beyond what could be achieved by just looking out the window.

For de Winkel this can mean two things: Either you need additional sensory information about the route, which also includes other senses, such as acoustic signals or altered vibration. "Or we have to consider the possibility that the previous assumptions about the origin of motion sickness are incomplete, and that the nausea is due to other causes."

Heinrich Bülthoff also sees the need for the development of autonomous vehicles to achieve the smoothest possible ride in the cabs. "Politicians often work in a moving car," he says. "But as a rule, they also have exceptionally well-trained chauffeurs, with a highly anticipatory and therefore very relaxed driving style." In addition, he believes that when developing autonomous vehicles, however, they will always have to ensure adequate visibility outside - especially in the direction of travel. "And if, instead of taking the highway, we then take a winding route, the occupants will probably not be able to avoid closing their computers and files and looking forward out of the vehicle onto the road.

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