A Globally Stabilizing Path Following Controller for Rotorcraft With Wind Disturbance Rejection

This brief addresses the design and experimental evaluation of a global controller to steer a quadrotor vehicle along a predefined path in the presence of constant wind disturbances. The proposed solution consists of a nonlinear adaptive state feedback controller for thrust and torque actuation that: 1) guarantees global convergence of the closed-loop path following error to zero in the presence of constant wind disturbances and 2) ensures that the actuation can be bounded as a function of the position and velocity errors without imposing a maximum for that bound, allowing for high performance control action. A prototyping and testing architecture, developed to streamline the implementation and tuning of the controller, is also described. Simulation results and experimental results, which include a hovering flight in the slipstream of a mechanical fan, are presented to assess the performance and robustness of the proposed controller.