A cascade controller architecture is designed to realize the attitude control of quadrotor with unknown disturbances in this article. The cascade controller integrates the advantages of the triple-step method and a nonlinear integral sliding mode. In the inner loop, an extended high-gain observer is designed to estimate total disturbance, including model uncertainty and external wind disturbance, in real time. Moreover, a nonlinear integral sliding mode with the capability of small error amplification and large error saturation is introduced to compensate for the estimated disturbance and track desired angular velocity. In the outer loop, a TD-based triple-step controller is designed to guarantee fast tracking of attitude angle. The convergence of tracking errors of both inner and outer loops is proved through the Lyapunov theory. Finally, both simulation and experimental results demonstrate the effectiveness of the proposed control method.

中文翻译：

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基于三步法和非线性积分滑模的未知扰动四旋翼飞行器姿态控制

本文设计了一种级联控制器架构来实现具有未知扰动的四旋翼飞行器的姿态控制。级联控制器综合了三步法和非线性积分滑模的优点。在内环中，设计了一个扩展的高增益观测器来实时估计总扰动，包括模型不确定性和外部风扰动。此外，引入了一种具有小误差放大和大误差饱和能力的非线性积分滑模来补偿估计扰动并跟踪期望角速度。在外环中，设计了一个基于TD的三步控制器来保证姿态角的快速跟踪。通过Lyapunov理论证明了内外环跟踪误差的收敛性。最后，