Research On Adaptive Sliding Mode Tracking Control Of Quadrotor UAV

In recent years,drones have demonstrated their outstanding capabilities in aerial photography,agricultural plant protection,equipment inspection,and public safety.Among them,the quadrotor UAV is widely used because of its simple structure,low manufacturing cost and strong maneuverability.The quadrotor UAV is a non-linear,highly coupled underdrive system.It is generally flying outdoors and is easily disturbed by the wind field.When the quadrotor UAV needs to complete some tasks,it will install various sensor devices on the fuselage,which may cause the mass and inertia moment of the fuselage to change,which requires the robustness of the quadrotor UAV control system.In addition,the quadrotor UAV must be able to withstand certain model uncertainties and system power mechanism failures.Aiming at the above situations,this paper will study the control strategy of quadrotor UAV to enhance the robust performance of control.First,according to the quadrotor UAV with different mechanical structures,its flight control mechanism is analyzed.Combining the definition of the coordinate system and related physical quantities required for the description of the quadrotor UAV motion process,the dynamic equations of translation and rot ation of the quadrotor UAV are derived respectively.Simulate and analyze the static stability and maneuverability of the quadrotor UAV.Secondly,according to the wind disturbance received by the quadrotor UAV during flight,it is subjected to force analysis in the wind field.The turbulence model is established.According to the principle of disturbance estimation and attenuation,a nonlinear disturbance observer is designed.Through the simulation of sinusoidal disturbance estimation,the effectiveness of the nonlinear disturbance observer is verified.Then,for the tracking control of the quadrotor UAV,two sliding mode controllers with exponential reaching law and adaptive reaching law were designed respectively.The Lyapunov stability criterion proves that the closed-loop system is stable.Through the simulation experiment under the disturbance of turbulent flow,it is found that the control input of the controller adopting the exponential approach law has large chattering,which also causes chattering during the attitude angle tracking process.However,the controller using an adaptive approach law controls the input amplitude to be significantly reduced,and the attitude tracking process becomes smooth.It shows that the sliding mode control with adapt ive approach law can effectively reduce chattering.Finally,considering the complex environment of the quadrotor UAV when performing tasks,a control strategy combining disturbance estimation and adaptive sliding mode control is designed.This control strategy combines the advantages of both sliding mode control and neural network,and uses simulated neural network online learning to adaptively adjust the sliding mode control parameters to adapt to the quality change of the quadrotor UAV body and the parti al failure of the power mechanism.The external disturbance received by the system can be estimated using a nonlinear disturbance observer and generate a compensation signal.Compared with the simulation of pure sliding mode control strategy,it is verifie d that the proposed control strategy still has good tracking performance when the quadrotor UAV is simultaneously subjected to external sinusoidal disturbance,mass change,and partial failure of the power mechanism.It shows that the designed controller h as strong robust performance.