Abstract:

Aiming at the problem of robust control for a six rotor UAV with complex disturbances, a robust control method based on sliding mode observer is proposed. Firstly, the mathematical models of the position and attitude of the six rotor UAV are established, and the sliding mode control law is designed for the position loop to solve the attitude command. Then, according to the virtual control law of the attitude loop output, the command filter is designed to suppress the differential explosion phenomenon, and the auxiliary filter is used to compensate the error of the command filter. Finally, the sliding mode observer is introduced into the angular velocity loop robust control law to compensate the complex disturbance including model error and external disturbance, which realizes the command filtering robust control of the six rotor UAV. The simulation results show that the proposed robust control law has better stability, accuracy and rapidity than the adaptive control method, the maximum error of position and attitude is only 0.05 m and 0.5° respectively, and the estimation error of sliding mode observer is only 0.2 （°）/s, which realizes the robust control of displacement and attitude for six rotor UAV in a shorter time.

Key words: six-rotor UAV, compound disturbance, command filter, sliding mode observer, robust control

摘要：

针对包含复合干扰的六旋翼无人机鲁棒控制问题，提出了一种基于滑模观测器的指令滤波鲁棒控制方法。建立了包含复合干扰的六旋翼无人机位置和姿态的数学模型，并对位置回路设计了滑模控制律，从而解算出姿态指令；根据姿态角回路输出的虚拟控制律，设计了指令滤波器来抑制微分爆炸现象，并利用辅助滤波器补偿指令滤波的误差；在角速度回路鲁棒控制律中引入滑模观测器，对包括模型误差和外界扰动的复合干扰进行补偿，实现了六旋翼UAV的指令滤波鲁棒控制。仿真结果表明：提出的指令滤波鲁棒控制律与指令滤波自适应控制方法相比，在复合干扰下具有更优的稳定性、准确性和快速性，位置和姿态的最大误差分别仅为0.05?m和0.5°，滑模观测器的估计误差也仅为0.2 （°）/s，能够在更短的时间内实现对六旋翼UAV位移和姿态的鲁棒控制。

关键词: 六旋翼无人机, 复合干扰, 指令滤波, 滑模观测器, 鲁棒控制