基于改进LESO的四旋翼无人机模糊线性自抗扰控制方法

Fuzzy Linear Active Disturbance Rejection Control of a Quadrotor UAV via an Improved LESO

四旋翼无人机系统具有参数不确定性及强耦合性的特点,其飞行性能容易受到外部干扰而下降.为了保证四旋翼无人机飞行的稳定性,本文提出了一种基于改进线性扩张状态观测器(Linear Extended State Observer,LESO)的模糊线性自抗扰控制方法.通过模糊算法自适应调节线性自抗扰控制器的参数,基于Levant跟踪微分器跟踪四旋翼无人机位置及姿态角的二阶微分信号进而提取四旋翼无人机系统的总扰动,使用总扰动偏差及偏差的微分作为输入的模糊控制器来优化LESO对总扰动的估计精度.此外,分析了LESO的收敛性及闭环系统的稳定性.最后通过对比仿真验证了所提控制策略的有效性,并从系统的控制信号,动态响应能力和抗干扰能力等方面对控制方案的性能进行了定量分析.

A quadrotor unmanned aerial vehicle(UAV)system is full of parameter uncertainties and strong cou⁃plings,and the performance of a quadrotor UAV is easily degraded by external disturbances.To ensure the flight stability of the quadrotor UAV,a fuzzy linear active disturbance rejection control based on an improved linear extended state observer(LESO)is proposed in this paper.Parameters of the linear active disturbance rejection control are adaptively adjusted by a fuzzy algorithm,and the second-order differential signal of position and attitude angle of the quadrotor UAV is extracted by a levant tracking differentiator,and then the total disturbance of the quadrotor UAV is extracted,the fuzzy controller takes the total disturbance deviation and its differential as input,thus optimizing the estimation accuracy of the LESO for the total disturbance.The convergence of the LESO and the stability of the closed-loop system are analyzed.Finally,the proposed control strategy is verified from the control signals,dynamic responses and of the robustness of the system.