基于改进扩展状态观测器的四旋翼无人机轨迹鲁棒跟踪控制

针对四旋翼无人机在轨迹跟踪过程中会受到内外部扰动、模型误差等不确定性因素的影响，本文提出了一种基于改进型扩展状态观测器的积分滑模控制方案。具体来讲，首先，将四旋翼无人机系统存在的模型误差以及内外部扰动等不确定性因素视作集总干扰，通过借鉴的改进扩展状态观测器对其进行观测；进而，在此基础上，进一步考虑四旋翼无人机系统控制的连续性，基于四旋翼无人机轨迹误差、速度误差、姿态角误差和姿态角速度误差设计积分滑模控制器，分析了系统的稳定性并分别进行了数值仿真和实机实验。结果表明，采用本文算法时，在数值仿真中，各状态跟踪误差不超过1%,跟踪精度最高；在实机实验中，位置跟踪误差总体上能控制在20%以下。因此，本文方法具备有效性和可行性。

Robust trajectory tracking control of quadrotor UAV based on the improved extended state observer

To address uncertainties which have influence on trajectory tracking of quadrotor unmanned aerial vehicle (UAV), such as internal and external disturbances, model errors, this article proposes an integral sliding mode control program based on the improved extended state observer. In particular, we firstly regard the uncertainty factors in the quadrotor UAV system, including model error, internal and external disturbances as lumped disturbances. The improved extended state observer is used to observe them. Furthermore, on this foundation, the control continuity of the quadrotor UAV system additionally is considered. An integral sliding mode controller is designed, which is based on trajectory error, velocity error, attitude angle error and attitude angular velocity error of the quadrotor UAV. The system stability is analyzed. The numerical simulation and real machine experiment are conducted. Results show that the tracking errors of each state in numerical simulation do not exceed 1% and the tracking accuracy is the highest. In actual machine experiments, the position tracking error can be controlled below 20% by using the proposed algorithm. For this reason, the proposed method in this article is efficacious and workable.