System Identification Approach for eVTOL Aircraft Demonstrated Using Simulated Flight Data

Abstract

This paper describes a system identification method for electric vertical takeoff and landing (eVTOL) aircraft. The approach merges fixed-wing and rotary-wing modeling techniques with new strategies to develop a modeling method for eVTOL vehicles using flight-test data. The eVTOL aircraft system identification approach is demonstrated through application to the NASA Langley Aerodrome No. 8 tandem tilt-wing, distributed electric propulsion aircraft using a high-fidelity flight dynamics simulation. Orthogonal phase-optimized multisine inputs are applied to each control surface and propulsor at numerous flight conditions throughout the flight envelope to collect informative flight data. An aero-propulsive model is identified at each flight condition using the equation-error method in the frequency domain. The local model parameters are then blended to create a global model across the nominal flight envelope. The identified models are shown to provide a good fit to modeling data with good prediction capability. The methodology is developed with a discussion of unique eVTOL vehicle aerodynamic characteristics and practical strategies intended to inform future flight-based system identification efforts for eVTOL aircraft.

A Novel Aerodynamic Modeling Method Based on Data for Tiltrotor evtol

“…Furthermore, aerodynamic modeling can offer an affordable and replicable simulation platform for designing flight control systems, assessing maneuvering stability, modifying designs, and other relevant aspects of evtol operations. Concurrently, aerodynamic modeling is the primary method used to describe evtol aerodynamic effects [4]. It reflects the variation characteristics of these effects with factors such as airspeed, configuration, tilt angle, and control surface deflection angle.…”