Design and Evaluation of a Unified Control Framework for Electric Vertical Take-off and Landing Vehicles

Kurzfassung

Urban Air Mobility (UAM) with Electric Vertical Take-off and Landing Vehicles (eVTOLs) promises an economic and ecological solution for the growing mobility demand. Tilt-wing eVTOLs (e.g., Airbus A3 Vahana) seem to be the most promis- ing ones because they combine the concepts of rotorcraft and aircraft. They offer an e?icient wing-borne cruise flight while reducing the need for ground-based infras- tructure at the cost of a complex control task. Tilt-wing vehicles increase the pilot?s workload and introduce possible failures due to mechanical complexity. A unified control concept can handle the vehicle in every phase and provides a single clean and intuitive interface. Since current research lacks a representative dynamic model of a UAM tilt-wing eVTOL suitable for control design, as well as a unified control concept, both these issues are addressed in this thesis. This work identifies the main physical phenomena governing tilt-wing eVTOLs. A six-degree-of-freedom rigid body model with an electric propulsion system is created. Since the aerodynamics are complex, a panel model is used in combination with additional methods to describe special tilt-wing effects. An integrated model in a compact mathematical representation is proposed. Control requirements for the design and evaluation of a unified control framework are identified, and a unified inceptor-command mapping is proposed. A modified Incremental Nonlinear Dynamic Inversion (INDI) control law fulfills these require- ments, e.g., linear stability margins are met, and the decoupling capability is proven. An outer-loop controller is designed according to the requirements to obtain a uni- fied control interface. Multiple command filters are implemented to cover various scenarios and to fly a complete UAM mission. The closed-loop system is evaluated by means of the control requirements and a UAM mission (e.g., air taxi scenario). The closed-loop system masters all parts of the mission and fulfills these requirements. The developed dynamic model and control system will be a valuable basis for future tilt-wing eVTOL research.