Path following for small UAVs in the presence of wind disturbance

This paper presents an alternative approach of designing a guidance controller for a small Unmanned Aerial Vehicle (UAV) to achieve path following in the presence of wind disturbances. The wind effects acting on the UAV are estimated by a nonlinear disturbance observer. Then the wind information is incorporated into the nominal path following controller to formulate a composite controller so as to compensate wind influences. The globally asymptotic stability of the composite controller is illustrated through theoretical analysis and its performance is evaluated by various simulations including the software-in-the-loop. Initial flight tests using a small aircraft are carried out to demonstrate its actual performance.