Robust fractional-order sliding mode control design for UAVs subjected to atmospheric disturbances

Trajectory tracking of unmanned aerial vehicles (UAVs) has been studied nowadays because it is necessary to design new controllers under different conditions. Severe atmospheric conditions are one of the major problems to overcome according to the path of the UAV. Conditions such as wind speed that can vary according to the weather conditions can affect the flight performance and of course in extreme cases can lead to stability problems. Some kinds of severe conditions are storms, snow, and hurricanes. These conditions are considered as disturbances in the roll, pitch, and yaw orientations of the UAV. This topic has been studied since several decades ago for piloted aircraft, but it is very important that these new contributions be provided in this field of UAV considering plenty of new potential applications. In this chapter, fractional-order sliding mode techniques are provided for the trajectory tracking of UAVs under severe weather conditions. First, it is important to model the disturbances generated by severe atmospheric conditions at different altitudes, using weather data from a specific country or region. After disturbance modeling, the fractional-order sliding mode controller design is done by implementing a Lyapunov approach. Numerical experimental examples of the proposed control laws are tested for different trajectories under different weather conditions and altitudes.