A nonlinear quadrotor trajectory tracking controller with disturbance rejection

• We design a nonlinear adaptive state feedback tracking controller for a quadrotor.
• The closed-loop system is asymptotically stable in the presence of force disturbances.
• Two methods of angular actuation are considered: angular velocity and torque.
• The actuation does not grow unbounded as a function of the position error.
• Experimental results are presented to demonstrate the performance of the controller.

This paper addresses the problem of designing and experimentally validating a controller for steering a quadrotor vehicle along a trajectory, while rejecting constant force disturbances. The proposed solution consists of a nonlinear adaptive state feedback controller that asymptotically stabilizes the closed-loop system in the presence of force disturbances. We consider two methods of angular actuation for the quadrotor, angular velocity and torque, and ensure that the actuation does not grow unbounded as a function of the position error. The constant force disturbance is estimated through the use of a sufficiently smooth projector operator. A prototyping and testing architecture, developed to streamline the implementation and the tuning of the controller, is also described. Experimental results are presented to demonstrate the performance and robustness of the proposed controller.