Control Of Quadrotor Aircraft With Uncertain Load:Design Based On Extended High Gain Observer

In recent years,with the rapid development of sensor technology,data processing technology and mechatronic technology,quadrotor aircraft has become more and more integrated into people’s production and life,and plays an increasingly important role.Quadrotor aircraft has the advantages of compact structure,flexible movement and convenient maintenance,and has wide application prospects in the fields of military,police,scientific research and civil use,and shows great application value.However,due to the highly nonlinear,under-actuated,and strong coupling characteristics of the quadrotor,how to control the quadrotor aircraft to perform complex tasks in a complex working environment has caused widespread concern in the control field.Especially when the quadrotor aircraft carries the load,how to deal with the disturbance caused by the load uncertainty on the quadrotor flight is worthy of further study.Firstly,the quadrotor aircraft with uncertain load is modeled by Newton Euler method,and the attitude controller model and position controller model are given respectively.In the modeling process of the attitude controller model,the influence of the uncertain load on the attitude dynamics of the quadrotor is fully considered,and the attitude controller model is rewritten into a form suitable for controller design through mathematical transformation.In the modeling process of the position controller model,the influence of the uncertain load on the position controller model is also given.At the same time,a simplified model of the position control is given,which can meet the requirements of the current position controller design and the future.The foundation of the high-performance position control algorithm for quadrotor with uncertain load is laid.Secondly,a nonlinear controller based on high gain observer is proposed for the attitude control problem of quadrotor aircraft throwing load.In this paper,the throwing load is treated as an uncertain disturbance,and an extended high-gain observer is designed to estimate the disturbance.Then,a backstepping control law is designed,and the estimated value of the extended high gain observer is used to compensate the disturbance in the control law.The numerical simulation shows that the controller has fast adaptability to the throwing load.In the design of the nonlinear controller,the high-order derivative of the desired command is estimated by designing the reference signal generator,and the coupling problem between the observer and the controller is solved by introducing saturation in the extended high-gain observer,and the Lyapuno is constructed.The function is used to prove the stability of the closed-loop system.Finally,in order to combine theory with practice and verify the performance of the proposed controller in practice,this paper designs a quadrotor aircraft experimental system with uncertain load.By developing a ground station that can update the control algorithm online,a quadrotor that can carry or throw loads,a communication device that can wirelessly communicate between the ground station and the quadrotor,and an indoor optical positioning system,the experimental system is easy to operate,stable and secure,small delay and easy to process data.In this experimental system,the controller proposed in this paper was compared with the cascade PID controller.The experimental results show that the proposed control algorithm can effectively overcome the influence of uncertain loads on the attitude control of quadrotor aircraft.