Quadcopter unmanned aerial vehicles (UAVs) systems are receiving remarkable attention from researchers due to their daily use in numerous applications, particularly at the current time where UAVs are playing a significant role in combating the COVID-19 pandemic. This paper is concerned with the problem of UAV navigation and control in the presence of uncertainty and external disturbances. It addresses this issue by proposing an improved adaptive sliding mode control (IASMC). Improved control law generates an adaptive switching gain achieving fast adaptation and robustness against both parameter uncertainties and external disturbances. Simultaneously, the control law allows for maintaining robust trajectory tracking with chattering attenuation. The performance of the proposed IASMC controller has been evaluated using a Matlab/Simulink platform. The obtained simulation results showed that the proposed IASMC control scheme as an inner loop controller is robust when dealing with uncertainties and can effectively track the desired trajectories while significantly attenuating the well-known chattering introduced by the SMC controller.

中文翻译：

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四旋翼无人机抖动衰减和轨迹跟踪自适应滑模控制器的改进设计

Quadcopter 无人机 (UAV) 系统因其日常在众多应用中的使用而受到研究人员的极大关注，特别是在当前无人机在对抗 COVID-19 大流行方面发挥着重要作用的时候。本文关注的是存在不确定性和外部干扰的无人机导航和控制问题。它通过提出一种改进的自适应滑模控制 (IASMC) 来解决这个问题。改进的控制律产生自适应切换增益，实现对参数不确定性和外部干扰的快速适应和鲁棒性。同时，控制律允许通过颤振衰减保持稳健的轨迹跟踪。已使用 Matlab/Simulink 平台对提议的 IASMC 控制器的性能进行了评估。