Research On Formation Control Of Quadrotor UAVs Based On Disturbance Observer

Due to the advantages of simple structure,small size,strong maneuverability,low cost,and vertical lift and fixed-point hovering,quadrotor UAVs are widely used in military,industrial,agricultural and other fields.Among them,the formation control of multiquadrotor UAVs is one of the important methods to study multi-quadrotor UAV systems.All quadrotors can form a formation,so as to realize complex group tasks that cannot be completed by a single quadrotor UAV.This paper takes the quadrotor UAV as the research object.Considering the characteristics of the quad-rotor UAV model with strong nonlinearity,strong coupling,under-actuation,and easy to be affected by external disturbances,the trajectory tracking of and formation control of the quadrotor UAVs is carried out,the main contents are as follows:Firstly,this paper summarizes the research background and significance,and introduces the research status of quadrotor UAV control methods and formation control,as well as the main work arrangement.Secondly,this paper introduces the body structure,flight mechanism and coordinate system of quadrotor UAVs.By analyzing the forces and moments of quadrotor UAVs during the flight,Newton’s laws of kinematics and Euler’s equation are utilized to establish the dynamic model of a rotary-wing drone.Also,the algebraic graph theory,Lyapunov stability theory,finite-time stability theory and related lemmas are introduced here.Thirdly,researching on the finite-time tracking control problem of quadrotor UAV under unknown environment disturbance and modeling uncertainty,a tracking controller based on finite-time disturbance observer is proposed.First,the unknown environmental disturbance and modeling uncertainty are combined into composite disturbance,and a finitetime disturbance observer is constructed to estimate the composite disturbance in real time.Secondly,a fast terminal sliding mode controller is designed in combination with the output of the disturbance observer,which eliminates the influence of compound disturbance and realizes the finite time tracking control of the quadrotor UAV.Using the finite time control theory,the stability of the observer and the controller is proved.The simulation results show that the designed finite-time disturbance observer and controller can realize the tracking of the preset desired trajectory by a single quadrotor UAV.Fourthly,the finite-time formation control problem of multi-quadrotor UAV under compound interference is studied.Considering the uncertainty of model parameters and the influence of unknown environmental disturbances,a distributed formation controller is constructed using the finite-time disturbance observer designed in Chapter 3.In the distributed formation controller,only part of the following quadrotor UAVs can receive the status information of the leading UAV,and then the quadrotor UAV model is divided into a position subsystem and an attitude subsystem.The position formation controller and attitude tracking controller are designed based on the estimation results of the finite-time disturbance observer,and then the stability of the designed formation controller is proved by Lyapunov stability and finite-time stability theory.Finally,the proposed distributed formation controller is simulated and verified,and the results show that the distributed formation controller designed in this paper can achieve the formation goal of multi-quadcopter UAVs.Finally,summarize the full text work,and look forward to the future research direction.