无人驾驶飞行器姿态的非线性扰动抑制控制

Nonlinear disturbance rejection control of unmanned aerial vehicle attitude

本文研究了无人驾驶飞行器(unmanned aerial vehicle,UAV)的姿态跟踪控制问题.针对在飞行器姿态跟踪时存在的系统模型不确定性和外界扰动,提出了一种基于四元数的姿态跟踪控制方法,基于UAV的姿态误差模型分别设计系统的观测器和控制器.首先,以四元数为姿态参数建立系统的非线性误差模型;在此基础之上,设计一种非线性干扰观测器(nonlinear disturbance observer,NDOB)用以在线估计误差模型中的复合扰动,并在控制输入端进行相应的补偿.然后通过设计非线性广义预测控制律设镇定误差系统,实现姿态跟踪.最后基于频域理论分析了非线性干扰观测器的扰动抑制性能.仿真与实验结果表明本文提出的方法在系统存在复合扰动的情况下能使系统姿态有效的跟踪期望值.

In this paper, the attitude tracking control problem of the unmanned aerial vehicle （UAV） is investigated. To deal with the model uncertainty and external disturbance, we propose an attitude tracking control method by which the controller and observer is designed respectively, based on the attitude error model, Firstly, according to the attitude dynamics of the servo system with quaternion as attitude parameters, the nonlinear error model is built. After that, the nonlinear disturbance observer （NDOB） is employed to online estimate the unknown compound disturbance and make compensation to the control input. Then, a nonlinear generalized predictive controller is designed to stabilize the error system and realize the attitude tracking. Finally, the performance of NDOB is analyzed by using the theory of frequency domain. The simulation and experiment results suggest that in the case of compound disturbance, the proposed method guarantees the system attitude to accurately track the desired value.