针对四旋翼飞行器轨迹跟踪问题中系统存在模型不确定和易受到外界扰动的情况，提出了基于切换函数的扩张状态观测器设计方法来对系统中的扰动进行估计，并将估计值与滑模控制器的设计相结合，实现了对系统中非匹配不确定性和匹配不确定性的抑制且实现了系统跟踪误差的一致最终有界。首先，根据变量间的耦合关系将飞行器系统模型分解为两个子系统模型，设计扩张状态观测器对子系统中的非匹配不确定性进行估计，并将估计值作为变量加入到切换函数的设计中；进而基于切换函数设计扩张状态观测器以估计经切换函数重构系统中的扰动，并在控制器中对扰动进行补偿。最后通过李雅普诺夫理论证明了控制系统的稳定性。通过仿真验证了本文提出的方法能够有效实现飞行器轨迹跟踪控制且能够抑止传统滑模控制的抖振现象。%This paper studies trace tracking control problem of quadrotor aircraft. To deal with the model uncertainties and external disturbances in quadrotor flying process, a novel sliding mode control based on extended state observer is proposed. System uncertainties are depressed and trace tracking errors are uniformly ultimately bounded under the proposed control law. Firstly, system model is divided into two subsystem models according to the coupling relationship between state variables. Extended state observers are designed to estimate mismatched uncertainties in the subsystem, and estimated values are added into switching function. Disturbances in the reconstructed system are observed by extended state observers designed based on the switching function, and they are rejected in the controller design procedure. Finally, system stability is proven through Lyapunov theory. The simulation results demonstrate the efficiency of the proposed control scheme for quadrotor trace tracking and the efficiency for depressing chattering phenomenon.
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