Toward an urban air mobility ride quality and safety assessment analytical tool

Electric vertical take-off and landing (eVTOL) aircraft will be central to future urban air mobility (UAM) transportation systems. Dynamic gust encounters due to urban terrain and neighboring aircraft can affect safety and ride quality, impacting community acceptance of UAM systems. Aircraft concepts currently under consideration for UAM systems differ significantly from conventional helicopters through use of multiple small prop-rotors distributed over the airframe. If a subset of these prop-rotors experiences large variations in inflow, the changing thrust could produce upsetting moments and dynamic responses with frequency response characteristics that may cause motion sickness and/or general discomfort to passengers. Thus, operation in the terminal area environment has the potential to negatively affect ride quality or result in loss of control accidents. Furthermore, notional aircraft concepts have complex aerodynamic interactions between the prop-rotor wakes and airframe, which are challenging from a modeling perspective. It is desirable to develop modeling and simulation tools for eVTOL aircraft handling / ride qualities analysis and flight control development to support development of air vehicle and UAM system development. This paper describes results of a research and development study of modeling methods and application toward an UAM ride quality and safety assessment tool. This tool combines a generic flight dynamics modeling framework, unsteady air flow models, and flight control design methods in cases where adequate handling/ride qualities and safe operation margins cannot be established.