This paper presents a novel autonomous shipboard landing control algorithm of a quadrotor subject to external disturbances and input saturation. A coupled six-degrees-of-freedom (6-DOF) nonlinear relative motion model is derived to facilitate the controller design. To overcome the under-actuated property of the quadrotor and avoid collision, the shipboard landing process is cooperatively completed by a relative position controller (RPC) and a relative attitude-altitude controller (RAC). The RPC is proposed for use when the quadrotor is far away from the ship, aiming to drive the quadrotor to the vicinity of the ship. The RAC is used for the situation when the quadrotor is close enough to the ship to land the quadrotor on the ship steadily. An adaptive backstepping technique is proposed for both RPC and RAC, where unknown bounds of the lump disturbances are estimated online by the adaptive laws. To satisfy the input constraint requirement, a smooth model is employed to describe the control input saturation. Stability analysis proves that all states of the closed-loop systems are uniformly ultimately bounded. A numerical example verifies the performance of the control approach.

中文翻译：

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具有输入饱和的四旋翼机自主舰载着陆的自适应反步控制

本文提出了一种受外部干扰和输入饱和影响的四旋翼飞行器自主舰载着陆控制算法。导出耦合六自由度 (6-DOF) 非线性相对运动模型以促进控制器设计。为了克服四旋翼的欠驱动特性并避免碰撞，舰载着陆过程由相对位置控制器（RPC）和相对姿态高度控制器（RAC）协同完成。RPC 建议在四旋翼远离船舶时使用，旨在将四旋翼驱动到船舶附近。RAC 用于四旋翼飞行器距离船舶足够近以将四旋翼飞行器稳定降落在船上的情况。为 RPC 和 RAC 提出了一种自适应反推技术，其中块扰动的未知边界由自适应律在线估计。为了满足输入约束要求，采用平滑模型来描述控制输入饱和。稳定性分析证明闭环系统的所有状态最终一致有界。一个数值例子验证了控制方法的性能。