Trajectory Tracking And Formation Control For Quadrotor UAV

The Quadrotor Unmanned Aerial Vehicles(QUAV)has been widely used in military and civilian applications,such as electric wires inspection,because of their own small size,simple machine configuration,low control cost,vertical take-off and landing,and autonomous hovering.Studying its autonomous tracking trajectory is the key to ensuring its safe flight and successful mission completion.However,a single UAV is limited by range,load,etc.,it is not capable of handling some specific operation scenes.In this case,multiple UAVs are used in formation to work together.Moreover,the efficiency of multi-UAVs formation operation is higher than that of a single UAV.UAVs can adapt to more application scenarios through formation collaboration,which has far-reaching research significance.In view of these practical application values,this paper investigates single UAV trajectory tracking control based on an in-depth study of the characteristics of the quadrotor UAV system model,taking into account that rapidity is an important indicator of system performance,and in turn extends its findings to the study of multi-UAVs formation control.The main contents are as follows:Firstly,a two-loop control structure containing position loop and attitude loop is proposed for the trajectory tracking problem of quadrotor UAV with time-varying perturbations.Based on the fixed-time control theory,a fixed-time sliding-mode controller is designed for the position and attitude of the UAV based on the non-singular double power sliding-mode control method,respectively.By introducing the idea of saturation control,the jitter effect which is common in the sliding mode control is eliminated,and the convergence time of the system tracking error is only related to the selection of the controller parameters by theoretical analysis.Finally,the simulation results show that the system state tracks to the desired trajectory in fixed time,which verifies the feasibility of the proposed control algorithm.Secondly,a fixed-time sliding mode formation control algorithm is proposed to consider the problem of multi-UAV formation tracking control.Firstly,the position relationship between the leader and the follower is established based on the formation structure of relative distance-azimuth Angle.Secondly,by using the sliding mode control method,a sliding mode formation control algorithm is designed for the follower system to make the UAV formation fly at a relative distance.Then,it is proved by theoretical analysis that the formation error converges to zero within a fixed time,which shortens the time required for the system to reach stability.The final simulation results show the effectiveness of the proposed control strategy.