Output-feedback control of the longitudinal flight dynamics using adaptative backstepping

An adaptive backstepping approach is used to design an output feedback control law for the longitudinal dynamics of an Unmanned Air Vehicle (UAV). The resulting nonlinear controller makes the system to follow references in the aerodynamic velocity and flight path angle, using elevator deflections and thrust as actuators. Only measurable quantities are used in the control and adaptation laws. The proposed strategy allows to design an explicit controller without any knowledge of the aerodynamic coefficients or the trim angle of attack, which also depends on the aerodynamic coefficients; only well-known qualitative physical properties from aerodynamics are used. Simulations are included for a realistic UAV model including actuator saturation.