Abstract:

A backstepping terminal sliding mode control scheme based on nonlinear disturbance observer
(NDO) is proposed in the presence of model nonlinearity, aerodynamic parameter and moment disturbance
uncertainties for maneuvers flight. The control scheme removes the priori condition of the upper bound of
uncertainties by using NDO to approximate uncertainties. Explosion of complexity is avoided by combining
dynamic surface control with the design virtual controller. A fast terminal sliding mode control strategy is then
used to improve convergence and steady-state tracking accuracy of the system. Using the Lyapunov stability
theorem, all signals in the closed loop system are guaranteed to be ultimately uniformly bounded. Simulation
of a nonlinear six-degree-of-freedom maneuvering flight of an aircraft is done. The results show effectiveness
of the proposed control scheme.

Key words: nonlinear disturbance observer (NDO), backstepping, dynamic surface control, fast terminal sliding mode control, maneuvering flight