基于改进自抗扰的四旋翼飞行器姿态控制

Attitude control of quadrotor based on improved auto disturbance rejection

针对飞行器控制系统易受外界干扰;自抗扰控制器采用非光滑fal函数,fal函数在原点附近存在拐点导致斜率较大,引起观测器观测效果不佳的问题。对自抗扰控制器中fal函数进行改进得到newfal函数,再对newfal函数进行分析。并且基于newfal函数重新设计了自抗扰控制器,得到新的离散型非线性状态误差反馈律(NLSEF)和扩张状态观测器(ESO)。最后基于牛顿第二定律和欧拉方程建立的四旋翼飞行器动力学模型设计了改进型自抗扰控制系统。仿真结果表明:newfal函数比fal函数具有更好的平滑性、连续性;采用newfal函数的自抗扰控制器有更优的观测性能;且在较大干扰时,抗干扰能力更好。

For the quadrotor control system is susceptible to large external interference;the auto-disturbance controller adopts a non-smooth fal function which has an inflection point near the origin resulting in a large slope, and causes poor observer observation. The fal function in the auto-disturbance controller is improved to obtain the newfal function, and the newfal function is analyzed. The auto-disturbance controller is redesigned based on the newfal function, and a new discrete nonlinear state error feedback law (NLSEF) and a new discrete extended state observer (ESO) are obtained. Finally, an improved auto disturbance rejection control system is designed for quadrotor aircraft nonlinear system based on Newton's second law and Euler equation. The simulation results show that the newfal function has better smoothness and continuity than the fal function;the auto-disturbance controller with newfal function has better observation performance;and when it has large i*nterference the anti-interference ability is better.