基于变速趋近律的离散滑模末制导律设计

摘要

针对离散化的末制导模型,基于一种新型离散变速趋近律设计了离散滑模制导律.利用该新型离散变速趋近律的特性消除了视线角速率的稳态振荡,使其渐进地趋于原点,并显著降低了系统抖振.将目标机动视为未知不确定性,采用干扰观测器方法对其进行在线估计和补偿,无需知道不确定性的界,只需知道其变化率有界,且无需满足匹配条件.仿真结果表明,所设计的基于新型离散变速趋近律的滑模制导律对目标机动具有鲁棒性,且无稳态振荡和系统抖振.%A discrete sliding-mode guidance laws based on a new discrete variable rate reaching law was proposed for the discrete form of the missile-target relative motion equation in plane. By adopting this reaching law, steady state oscillation and system chattering were eliminated significantly, and system state approached to zero diminishingly. Maneuvering acceleration of target was considered as unknown external disturbance, and disturbance observer was adopted to estimate and compensate for the uncertainties, which required just knowing the possible variation range of target acceleration between two adjacent sampling instants rather than a prior knowledge of the target acceleration bounds or matched conditions. The simulation results show this method has strong robustness, without steady state oscillation and system chattering.