Quadrotor Gray-Box Model Identification from High-Speed Flight Data

TLDR

The study investigates aerodynamic effects on a quadrotor in high‑speed flight and aims to develop an accurate nonlinear model via free‑flight wind tunnel tests. Gray‑box models incorporating rotorcraft aerodynamic knowledge were identified from flight data using a stepwise system identification approach and compared against existing models. Flight data show complex aerodynamic interactions that invalidate helicopter‑based models, and the gray‑box models reduce moment residuals by 80% and force residuals by 20%.

Abstract

To explore the aerodynamic effects on a quadrotor in the high-speed flight regime and establish an accurate nonlinear model, free-flight tests with a quadrotor are carried out in a large-scale wind tunnel. The flight data reveal that complex aerodynamic interactions could appear and significantly influence the forces and moments acting on the quadrotor, which indicate the inaccuracy of state-of-art models established based on helicopter aerodynamic theory. To cope with this problem, gray-box models considering these effects are identified from flight data using a stepwise system identification approach, which combines both prior knowledge of rotorcraft aerodynamic properties as well as data observations. Previous models introduced in the literature are compared with the gray-box models. Validation results show an 80% reduction of moment model residuals and a 20% reduction of force model residuals.