Research Of Quad-rotor UAV Trajectory Tracking Control Methods

The quad-rotor UAV is one of the unmanned micro arial vehicle with vertical take-off and landing capability.With the advantages of small size and excellent performance,operating easily etc.It is getting more and more extensive application in many applications such as aerial reconnaissance,search and rescue missions,power inspection and aerial cinematography.However,the quad-rotor UAV is a nonlinear,strong coupling and underactivity system,which brings difficulty to the establishment of the dynamic model,the acquisition of the flight attitude information.The trajectory tracking flight control methods of the quadrotor under the influences of turbulent wind filed,timing-varying mass of load and asymmetric load whose mass and shape are both unknown are studied.The main research contents are as follows:Firstly,the ground coordinate system and the body coordinate system are selected and conversion relation between them is derived.The UAV is designed using Euler angle by the paper.According to the Newton-Euler equation,a six-DOF(Degree of Freedom)nonlinear dynamics models are successfully established.In order to solve the problem of underactuated and strong coupling,the virtual controllor is designed to deal with the model.The overall control scheme based on the inner and outer loops is designed.Secondly,a trajectory tracking flight control method of the quadrotor with the turbulent wind filed is studied.The characteristics of the natural wind field are analyzed to establish a corresponding mathematical model,A new type of sliding mode control of position loop and attitude loop,called the proportional-integral-derivative-nonsingular fast terminal sliding mode control(PID-NFTSMC)is designed,and a finite-time Extended State Observer(FTESO)is used to estimate the influence of the wind filed.The flight control method is proposed to ensure that the quadrotor has higher tracking accuracy and flight save under the wind filed.Thirdly,a trajectory tracking flight control method of the quadrotor with the timingvarying mass of load is studied.The impact on the total system caused by timing-varying mass of load equipped with body of the quadrotor is analyzed.The nonlinear dynamic models of the quadrotor with timing-varying mass of load are established via Newton-Euler formalism.The timing-varying mass of load and modeling uncertainties of the quadrotor are estimated by adaptive RBF neural network.Compensating for external disturbances and approximate error of neural network by the nonlinear damping function.Combined with dynamic surface control,to design a trajectory tracking flight control method of the quadrotor with the timing-varying mass of the load.Finally,a trajectory tracking flight control method of the quadrotor with asymmetric load whose mass and shape are both unknown is studied.The impact on the total system caused by asymmetric load whose mass and shape are both unknown is analyzed,and the dynamic equations of the multi rotor UAV system are introduced.An adaptive non-singular fast terminal sliding mode control scheme is proposed in this chapter.However the design of the control method is based on assumption that the mass and shape of load,the modeling uncertainty and the bound value of the external disturbances,but it is very expensive and difficult to obtain these parameters in real practical application.To exclude the required assumption,an adaptive fuzzy nonsingular fast terminal sliding mode control(AFNFTSMC)controller is developed to ensure that the quadrotor with asymmetric load has higher tracking accuracy.