Research On Tracking Control Of Quadrotor Hanging Flight Trajectory Under Wind Field Interference

With the continuous progress of science and technology,people’s research on unmanned aerial vehicles(UAVs)has been deepened and the application fields of UAVs have been expanded.Due to its small size,high maneuverability and low cost,the study of using UAVs to hang loads for material transportation has also received increasing attention from experts and scholars recently.Due to the loading of UAVs with suspended loads,the degree of freedom of the vehicle increases,the coupling degree increases and the stability decreases.Therefore,it is very necessary to study the trajectory tracking of the vehicle under the wind field interference to ensure the safe and stable completion of the mission.Based on this,this thesis mainly focuses on the trajectory tracking accuracy problem and wind field interference resistance of quadrotor hanging system,and combines the theoretical methods of integral backstepping sliding mode method,adaptive control,neural network and interference observer to give a nonlinear anti-disturbance control method for quadrotor hanging system,and through theoretical derivation,stability check,and analysis of simulation results,it proves that The proposed control scheme is effective for tracking the trajectory of a quadrotor flight control system with a suspended load.The key research elements of the thesis include.Firstly,the mathematical model of the quadrotor with suspended load is derived by adding the suspended load to the mathematical model of the original quadrotor.At the same time,the models of mean wind and turbulent wind are established to obtain the wind disturbance model in this thesis.Secondly,an error-based adaptive integral backstepping sliding mode controller is designed for the flight stability of the load in the relative wind field affected by the mean wind,which is used in the quadrotor hanging system.Through simulation experiments,it is demonstrated that the algorithm proposed in this chapter can effectively reduce the influence of mean wind disturbance on the system,and the swing angle controller can rapidly reduce the swing angle of the suspended load,which improves the anti-disturbance performance of the system.Then,for the problem that the load is susceptible to complex uncertain time-varying relative wind field,a neural network is introduced to approximate and compensate the disturbance term online,and a trajectory tracking control scheme based on neural network and integral backstepping sliding mode is designed for the quadrotor hanging system.The control strategy is demonstrated to reduce the oscillation of the suspended load under complex disturbance conditions and improve the accuracy of trajectory tracking and the anti-disturbance of the system.Finally,a nonlinear integral backstepping sliding mode controller is designed based on the disturbance observer for a flight system subject to complex relative wind field disturbances and parameter uncertainties,and a hyperbolic tangent function is used in the motor module instead of the saturation constraint function considering the signal input constraint problem.Through the nonlinear control simulation of the quadrotor hanging system,it is demonstrated that the quadrotor hanging system controller with interference observer can accurately track the motion trajectory of the quadrotor hanging system under uncertain interference and can rapidly suppress the swing of the hanging load in flight to offset the error caused by the interference,which is suitable for the flight control system of quadrotor hanging flight.