Backstepping H-Infinity Control of Unmanned Aerial Vehicles with Time Varying Disturbances

In this paper, a backstepping H-Infinity controller for unmanned aerial vehicles (UAV) with time varying disturbances is proposed. The type of unmanned aerial vehicle analyzed in this paper is a quadrotor type, which is divided into position and attitude dynamics. Time-variable disturbances that may be caused by atmospheric or other forms of environmental conditions are considered, taking into consideration the mathematical conditions that describe the form of disturbance modeled on the position dynamics. The design of the H - Infinity backstepping controller is based on a recursive methodology by applying the respective virtual inputs and considering the conditions for the disturbance rejection control. The attitude and position of the backstepping control inputs are determined by selecting the appropriate Lyapunov functions to satisfy the stability conditions of the closed loop. Two numerical examples are presented to test and validate the theoretical results obtained in this analysis. Two types of reference variables are used to verify the position and attitude of the controller and the system response.