On the Impact of Flight Control Systems on Kinetosis of Helicopter Passengers

Disorientation, nausea, and vomiting of passengers that result from vehicle vibrations are characterized as kinetosis or motion sickness. It is mainly the low-frequency movements of these vehicles that contribute to the kinetosis of passengers. Frequencies that provoke kinetosis lie within the rigid-body flight characteristics of helicopters, which depend, among other things, on the design parameters of the flight control system. Moreover, the flight control system's reaction to atmospheric turbulence leads to low-frequency vibration that can result in kinetosis of the passengers and decrease the ride comfort of the helicopter. It is necessary to understand which movements of the helicopter cause kinetosis to develop countermeasures. Therefore, an extensive experimental campaign was conducted as part of a national research project. The campaign's results show that kinetosis in helicopters depends on the number of motion degrees of freedom and that the existing assessment method in ISO2631-1 is not able to reflect this correctly. Furthermore, based on the results, it can be assumed that the extent of kinetosis depends on the flight control system since the investigated flight control systems lead to different vibration spectra that expose the passengers. Therefore, consideration of kinetosis and thus ride comfort is recommended for the design procedure of future flight control systems.