Adaptive Control for Aircraft Longitudinal Dynamics with Thrust Saturation

Abstract

An output-feedback control law is designed for the longitudinal flight dynamics of an aircraft. The proposed control law is designed using the adaptive backstepping method and does not require any knowledge of aircraft aerodynamics beyond well-known qualitative physical properties. The resulting feedback controller is able to follow given references in both airspeed and flight-path angle by actuating elevator deflections and aircraft engine thrust. Engine physical limits are incorporated into the design by using a Lyapunov function analysis that includes saturation, obtaining a novel hybrid adaptation law that guarantees closed-loop system stability. Simulation results show good performance of the feedback law and, in particular, demonstrate that the hybrid adaptation law improves the behavior of the closed-loop system when saturations are present. A degraded scenario (a sudden cargo displacement that renders the aircraft statically unstable) is also considered to show the adaptation capabilities of the control law. The simulations are carried out using a realistic aircraft model that is also developed in the paper.

Trajectory tracking for fixed-wing UAV using model predictive control and adaptive backstepping

“…The stability properties and the controller performances have been published by the authors in reference Gavilan et al (2015). Thus, we only describe here a brief summary, for the sake of completeness.…”

“…For the flight path angle controller, we use an approach similar to the one shown in Gavilan et al (2015). However, in that case, the controller was formulated to operate solely in the vertical plane, thus not considering turning flights.…”

“…The longitudinal controllers are based on a novel adaptive backstepping approach, which can handle the airspeed and the flight path angles without knowing any aerodynamic parameter, beyond well known aerodynamic properties. The formulation of these controllers has been partially published by the authors in Gavilan et al (2015), so that in this paper, we extend the flight path angle controller to operate in turning flights.…”

Longitudinal Attitude Control Decoupling Algorithm Based on the Fuzzy Sliding Mode of a Coaxial-Rotor UAV

“…The general attitude control system of the UAV coordinates and controls the longitudinal, lateral and heading channels. The design of the longitudinal channel controller is the most critical and complex of the three channels, and its control rate significantly affects the UAV's flight performance [6,7]. In the literature [8], the decoupling control method is used to design the aircraft control system.…”

Disturbance Rejection Flight Control for Small Fixed-Wing Unmanned Aerial Vehicles

“…In recent years, robust adaptive control techniques have been applied to the longitudinal channel of air-breathing hypersonic vehicles with flexible structures and non-minimum phase behaviors [10,11]. In terms of small UAVs, reference [12] has proposed a novel adaptive backstepping method to tackle the system uncertainties as well as thrust saturation.…”