四旋翼无人机鲁棒自适应姿态控制

Quadrotor UAV Robust Adaptive Attitude Control

四旋翼无人机的姿态控制是自主飞行控制的核心,针对四旋翼姿态易受外界环境干扰和内部参数摄动等不确定性影响的问题,设计了一种鲁棒自适应反步控制器,以提高四旋翼的鲁棒性。建立了四旋翼完整的姿态运动模型,并将其转化为含有广义不确定性的多输入多输出非线性系统。根据该系统满足严格反馈的结构特点,设计了反步控制器;针对系统中存在的外部干扰和内部参数摄动等不确定性,引入了一类鲁棒自适应函数来抵消该不确定性对系统的影响;采用非线性跟踪微分器估计虚拟控制量的微分信号,减小了反步控制器设计中普遍存在的"计算膨胀"问题;通过构造Lyapunov函数证明闭环系统是稳定且指数收敛的。仿真结果表明,所设计控制器具有良好的控制效果和鲁棒性。

The attitude control is the key of the automatic flight control for quadrotor UAV. In order to improve the robustness of quadro- tor UAV for various uncertainties, a robust adaptive backstepping controller is designed. The whole attitude kinematical model is ob- tained and translated into a MIMO nonlinear system with generalized uncertainty. Because the design feature of the system is strict feed- back, the baekstepping controller is designed. A robust adaptive function is designed to counteract the influence of the uncertainties, which include external disturbance and interior parameters perturbation. The nonlinear tracking differentiator is introduced to estimate the differential signal of the virtual control law and to reduce the ＂computer explosion＂ problem which is ubiquitous in the backtepping controller. The closed -loop system is proved to be stable and converge exponentially through constructing Lyapunov function. Simula- tion results are presented to corroborate the effectiveness and robustness of the proposed control strategy.