Attitude Control And Trajectory Tracking Control For Quadrotor UAV

In recent years,due to its simple structure,strong maneuverability and low cost,the quadrotor has been widely used in many fields.Not only in traditional aerial photography,but also the quadrotor shows great application potential in the fields of military and civil,and is used to carry out various missions.The design of quadrotor control system affects its flight performance so there is a far-reaching significance for autonomous flight.With the complexity of the flight mission,higher requirements are placed on the design of the flight control system.Based on nonlinear control theory,a study on the attitude control and trajectory tracking of the quadrotor is carried out in this paper.The main contributions of this dissertation are as the follows:Aiming at the quadrotor with constraint lift,a combined sliding mode controller design method is proposed to solve the problems such as input saturation,body parameters and structured uncertainty in actual flight,and realize fast trajectory tracking,.Firstly,the dynamic model of the quadrotor is divided into a fully-actuated subsystem and an under-actuated subsystem.Furthermore,a non-singular fast terminal sliding mode control method is used in the fully-actuated subsystem.A sliding mode control method with the dual-power sliding mode reaching law is used in the under-actuated subsystem.It makes further improvement on the convergence speed,improve the quality of dynamic motion and enhance the ability of anti-interference and parameter perturbation.Finally,the convergence characteristics and Lyapunov proofs of the subsystems are analyzed.Through simulation experiments of waypoint tracking and continuous trajectory tracking,the results show the rapidity,robustness and superiority of this control method.Aiming at the high precision trajectory tracking for the quadrotor under large external disturbance,a double-loop exact nonlinear trajectory tracking controller design method is proposed.Firstly,the structure of control system is divided into inner loop and outer loop.Then,an immersion and invariance controller based on fal function is proposed for the outer loop.An adaptive global sliding mode inner loop control method based on immersion and invariance is proposed for the inner loop.They improves the control accuracy and the ability of anti-interference.Finally,the simulation results show that the control method has a faster convergence speed and the better quality of motion.