说明：  四旋翼无人机是一种可以被遥控也可以在无人为控制的状态下执行预定任务的飞行器，与传统直升机相比四旋翼飞行器的机械结构简单，且具有高精度，灵活精度以及较低成本的特点，被广泛用于军事侦察，农艺播撒、快递派送、摄影工作等领域。四旋翼飞行器自身具有欠驱动、多变量、非线性等特性，在外界的噪声干扰情况下，增加了四旋翼无人机的不稳定以及控制系统的设计难度。所以对四旋翼飞行器的位姿控制的研究，可以开拓科研人员对控制算法以及滤波算法的认知，具有重要的研究意义。
(Four-rotor UAV is a kind of aircraft that can be controlled remotely or perform scheduled tasks without human control. Compared with traditional helicopters, the Four-rotor UAV has simple mechanical structure, high precision, flexible precision and low cost. It is widely used in military reconnaissance, agricultural broadcast, express delivery, photography and other fields. Four-rotor UAV has the characteristics of under-actuation, multi-variable and non-linearity. Under the circumstance of external noise, the instability of Four-rotor UAV and the difficulty of control system design are increased. Therefore, the research on attitude control of Four-rotor aircraft can broaden the knowledge of control algorithm and filtering algorithm for researchers, and has important research significance.)