Research On The Stability Control Method Of Unbalanced Load Of Quadrotor UAV Suspensio

In recent years,quadrotor UAV have been widely used in various fields because of their simple structure,high mobility and high flight accuracy.For transport quadrotor UAV,they usually carry different types of loads larger than their own weight in their missions.In this case,due to the flight characteristics of quadrotor UAV,changes in the weight,center of mass and rotational inertia of the loads tend to affect the stability of the UAV’s motion state,and also make the UAV system more sensitive to external disturbances.In order to improve the flight stability and trajectory tracking accuracy of the UAV under various load changes and external disturbances,this paper takes the quadrotor UAV as the research object,and conducts the dynamics modeling and stability control method research considering the unbalanced load of suspension and unknown external disturbances.The research contents of this paper are as follows:(1)The basic structure and motion principle of the quadrotor UAV are analyzed,and the kinematic analysis and dynamics modeling of the quadrotor UAV and the suspended unbalanced load are carried out separately.By considering the suspension load as the external force and external moment of the UAV system into the quadrotor UAV dynamics model,the dynamics model of the quadrotor UAV suspension unbalance load system is established.(2)A finite-time convergence control method is proposed to address the effects of unbalanced load swing and external unknown perturbations on the tracking performance of the quadrotor UAV motion state in the motion process.Firstly,the quadrotor UAV controller is decoupled into a position controller and an attitude controller by using an inner and outer loop structure.Then the outer-loop position non-singular fast sliding mode controller and the inner-loop attitude inversion non-singular integral sliding mode controller are designed for the quadrotor UAV control system,and stability analysis is performed respectively.Finally,the reliability of the controllers and the finite-time convergence of the UAV system states are verified by simulation analysis.(3)On the basis of the finite-time convergence control method,a sliding mode control method based on improved active disturbance rejection control is designed by further considering the influence of compound disturbances such as unbalanced load swing,model inaccuracy and the unknown Firstly,the expanded state observer in the active disturbance rejection control is improved.Then the improved active disturbance rejection control is combined with the finite-time convergence control method to design the position controller and attitude controller respectively,and the model accuracy requirement of the position controller is reduced by designing the mass estimation algorithm in the position controller;the attitude controller further improves the system state tracking performance by introducing the super-twist algorithm.Finally,the reliability and effectiveness of the controller are verified by simulation analysis.(4)Build a quadrotor UAV experimental platform,apply the design control method in the experimental platform,and further verify the feasibility of the design control method by flying the quadrotor UAV with unbalanced load.