Disturbance observer based dynamic inversion control for a wind tunnel free-flying test of a blended-wing-body aircraft

Abstract

This paper proposes a disturbance observer based dynamic inversion control law for the wind tunnel free-flight test of the directional static unstable blended-wing-body aircraft. Considering that nonlinear control system is usually affine nonlinear system for control design, thus the original wind tunnel aerodynamic coefficients are transformed into aerodynamic derivative form by the weighted least squares method and transformation errors are regarded as external disturbances. The classical nonlinear dynamic inversion control is widely implemented in the practical engineering but sensitive to the model errors, this paper designs the disturbance observer to estimate the aerodynamic model errors, then compensates the errors in the dynamic inversion control loop. Moreover, this paper analyzes the stability of the control system and estimates tracking error upper bound. Finally, the proposed method is verified by the simulation experiment of the blended-wing-body aircraft.