Precise Path Following Control Of Small-scale Flying-wing Unmanned Aerial Vehicle

With the increasing importance of UAVs in the civil and military fields,the development of UAV technology has attracted the attention of countries all over the world.Due to the special tailless Blended Wing Body（BWB）aerodynamic layout,the flying-wing UAV has a maneuvering advantage that the conventional UAV can not match.Generally,UAVs need to complete flight tasks autonomously,and trajectory control is an important manifestation of UAV’s autonomous performance.In response to this,this article explores and studies the track tracking control of flying-wing UAVs.First of all,in order to facilitate the mathematical expression of the flying-wing UAV,a complete coordinate system is established,and the dynamics and kinematics characteristics of the flying-wing UAV in each coordinate system are modeled and analyzed,and the complete derivation is summarized.Six-degree-of-freedom non-linear mathematical model,and based on the principle of small disturbance,respectively derives the linearized state space equations of the horizontal and vertical channels,which lays the foundation for subsequent research work;Then,on the basis of the mathematical model of the UAV,the classical PID control theory is used,the continuous closed loop architecture is used,and the horizontal and vertical channels of the flying-wing UAV are analyzed in detail with the design idea of "inside first and then outside".The channel control law design forms a control architecture with attitude control as the inner loop and track control as the outer loop.The simulation analysis of different channels verifies the effectiveness of the set control loop.Finally,based on the vector field guidance method,the trajectory tracking strategy of the flying-wing UAV is designed and analyzed when facing a straight line expected track and a circular expected track,and the accurate track tracking under wind interference is realized.When designing the linear-circular composite track guidance law,a waypoint switching tracking method with the space half-plane as the switching condition is used,and the transition between different tracks is realized with a smoother arc-shaped track.Through simulation analysis,it is verified that the flying-wing UAV can track different tracks under this method.