عنوان مقاله [English]
One of the main concerns in the field of promoting autonomy level of Unmanned Air Vehicles (UAVs) is guidance system which is designed to enable UAVs to fulfill their missions, especially through uncertain atmospheric conditions. The UAV should be able to complete the mission in a robust manner. Therefore, the current study is to provide a robust guidance system for UAV's. The designed guidance law should perform the mission, defined by a set of waypoints, in presence of wind and turbulence as efficiently as possible. In those parts of the path with small radii of curvature or when the UAV flies within the wind and turbulence, the classic guidance laws such as Pure Pursuit and Proportional Navigation undergo severe losses in their performance. In order to flight through a series of waypoints, while considering the UAV nonlinear six degrees of freedom dynamic model, a new robust guidance law is designed, based on the Pure Pursuit Guidance law and sliding mode control approach. Then, in order to increase the efficiency of the Pure Pursuit Sliding Mode Guidance and to reduce the undesired phenomenon of chattering, the desired guidance law is combined with a fuzzy control approach. Then, dynamic inversion is used for attitude control. The performance analysis of the newly developed guidance law, Pure Pursuit Fuzzy Sliding Mode Guidance, is evaluated through a series of scenarios without turbulence and wind and with turbulence and wind effects. The six degrees of freedom simulations reveal the superior performance
of the proposed approach in comparison with the pure pursuit guidance law.