固定时间扩张状态观测器下的四旋翼飞行器滑模控制策略

针对滑模控制中系统状态接近滑模面后存在的抖颤现象，提出一种基于固定时间扩张状态观测器(FTESO)的二阶滑模控制策略.首先，设计全驱动子系统及欠驱动子系统的控制结构中的二阶滑模控制器；然后，通过FTESO对内部的参数不确定及外部扰动进行观测，在一定时间上限内收敛到观测值，利用观测值对控制器进行补偿，从而减少甚至消除抖颤现象；最后，通过李亚普诺夫函数保证设计的四旋翼飞行器系统的闭环稳定性，并进行仿真实验.结果表明：文中提出的控制策略具有优越性.

Sliding-Mode Control Strategy of Quadrotor With Fixed-Time Extended State Observer

Aiming at the chattering phenomenon after the system approaching the sliding-mode hyperplane in sliding-mode control, a second order sliding mode control strategy base on fixed-time extended state observer(FTESO)is proposed. Firstly, the second order sliding-mode controller is designed in the control structure of fully-actuated subsystem and under-actuated subsystem. Then, the internal parameter uncertainties and external disturbances are observed by FTESO, which converge to the observed values within a certain time limit, the observed values are used to compensate the controller, so as to reduce or even eliminate the chattering phenomenon. Finally, the closed-loop stability of the designed quadrotor system is guaranteed through Lyapunov function, and simulation experiments are carried out. The results show that the proposed control strategy in this paper has advantages.