L1 adaptive control for Wind gust rejection in quad-rotor UAV wind turbine inspection

This work presents preliminary results of the control method developed for autonomous inspection of wind turbines. High wind gusts are a major deterrent of outdoor Unmanned Aerial Vehicle (UAV) operations, in which, common classical control methods such as Proportional-Integral-Derivative (PID) control do not perform well. Therefore, more robust adaptive control methods must be employed. We propose the use of an L
₁
adaptive velocity controller that is capable of fast adaptation and guaranteed robustness while withstanding any disturbances encountered during flights. Considerable increase in performance of the L
₁
adaptive controller is demonstrated by comparing the proposed approach to a Linear Quadratic Regulator (LQR) method in simulation and a benchmark PID controller in several real flight experiments with added wind gusts.