Non-linear flight control for unmanned aerial vehicles using adaptive backstepping based on invariant manifolds

Abstract

A novel adaptive backstepping control scheme based on invariant manifolds for unmanned aerial vehicles in the presence of some uncertainties in the aerodynamic coefficients is presented in this article. This scheme is used for command tracking of the angle of attack, the sideslip angle, and the bank angle of the aircraft. The control law has a modular structure, which consists of a control module and a recently developed non-linear estimator. The estimator is based on invariant manifolds, which allows for prescribed dynamics to be assigned to the estimation error. The adaptive backstepping control law combined with the estimator covers the entire flight envelope and does not require accurate aerodynamic parameters. The stability of the whole closed-loop system is analyzed using the Lyapunov stability theory. The full six-degree-of-freedom non-linear model of a small unmanned aerial vehicle is used to demonstrate the effectiveness of the proposed control law. The numerical simulation result shows that this method can yield satisfying command tracking despite some unknown aerodynamic parameters.

Robust constraint backstepping control for high-performance aircraft with account of unsteady aerodynamic effects

“…Since traditional linear control methods are incapable of addressing such challenges, 1 a number of nonlinear control techniques have been extensively investigated to ensure adequate stability and performance in these extreme flight conditions, such as dynamic inversion, 2,3 neural network, 4 fuzzy logic, 5,6 adaptive and backstepping control. 7–9…”

Disturbance observer based dynamic surface flight control for an uncertain aircraft

“…For the formulation of system (1), we know that it is a time-varying nonlinear system with unknown uncertainties and disturbances. Since the system satisfies the block low-triangular structure, [38][39][40] backstepping technique is the most natural control method for such a type of nonlinear system. However, the repeated differentiations of the virtual controls in traditional backstepping design would lead to the problem of ''explosion of complexity''.…”

“…Recently, the backstepping approach as a nonlinear design method has been introduced to design the flight controller, and the system's stability can be guaranteed by using Lyapunov stability theory. [5][6][7][8][9][10] Moreover, backstepping provides more flexibility in dealing with nonlinearities compared with the feedback linearization approach. However, it should be pointed that ''explosion of complexity'' of traditional backstepping approach dramatically increases the complexity of implementation.…”

Adaptive fuzzy multi‐surface sliding control of multiple‐input and multiple‐output autonomous flight systems

“…Recently, several non‐linear control techniques have been proposed for aerial flight, such as feedback linearisation, non‐linear dynamic inversion [5–7], sliding mode control [8, 9] and adaptive control techniques utilising back‐stepping and super‐twisting methods [10–13]. In [5], the original non‐linear dynamic system is transformed into a linear system by coordinate transformation and state feedback.…”

“…This is generally not the case, as accurate mathematical models can be very difficult to obtain. In [10], an adaptive back‐stepping controller was designed that utilised invariant manifolds to track angle of attack, side‐slip angle and roll angle, however the paper only focused on flight stability, and did not address trajectory tracking. In [8], a quasi‐sliding control methodology was designed to control airspeed and attitude for flight.…”