固定时间收敛扰动观测终端滑模制导律设计

针对机动目标拦截问题,设计了基于固定时间收敛扰动观测器(fixed time disturbance observer, FxTDO)的终端角度约束非奇异快速终端滑模制导律(nonsingular fast terminal sliding mode guidance law, NFTSMGL)。通过具有固体时间收敛特性的扰动观测器对导弹拦截过程的外部扰动进行快速、精确估计。同时为了抑制抖振影响以及保证制导信号在有限的时间范围内收敛,设计了NFTSMGL,并进行了稳定性分析。仿真结果表明，FxTDO-NFTSMGL可以使制导信号在有限的时间范围内收敛至期望状态,并满足对机动目标拦截的要求,相较于无观测器的NFTSMGL收敛速度更快,且避免了抖振现象。

Fixed time disturbance observer based terminalsliding mode guidance law

An impact angle constrained nonsingular fast terminal sliding mode guidance law (NFTSMGL) based on fixed-time disturbance observer(FxTDO) is designed in the presence of uncertain disturbances. FxTDO is used to accurately estimate the internal and external disturbance in the process of missile interceptor. In order to attenuate the chattering and ensure the convergence of guidance system within finite time, a NFTSMGL method is adopted. The stability analysis is carried out. The simulation results show that FxTDO-NFTSMGL can be used to converge the guidance system at a limited time and meet the requirements of maneuvering target interception. Compared with NFTSMGL, the guidance law has a fast convergence speed and avoids the chattering problem.