Adaptive Control Laws for Controlling a Quadrotor in Attitude: An Experimental Approach in Outdoor Environments

This work presents four robust adaptive control laws for a quadcopter drone subject to wind-gust disturbances. The four robust adaptive control laws are based on nonlinear backstepping and sliding-mode techniques to improve robustness. The four control laws compared are: adaptive backstepping, adaptive backstepping with first-order sliding modes, adaptive backstepping with second-order sliding modes, and adaptive backstepping with high-order sliding modes. The contributions of this work are that the experimental results presented are significant and experimentally meaningful. These control laws aim to stabilize a quadcopter’s roll, pitch, and yaw angles through outdoor experimental tests (real-time flights), where the quadcopter is subjected to external disturbances from unknown wind gusts. Another contribution is that, to conduct the experiments, we assembled, designed, and programmed a quadcopter with low-cost components and used the control laws proposed in this work to achieve outdoor attitude control.