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

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.