Based on Hill guidance, the optimization of trajectories for the manned maneuvering unit rescuing an astronaut or equipment that becomes separated from a space station is studied because of minimum fuel, rendezvous accuracy, and time constraint requirements. The Hill guidance targeting errors induced by navigation error, target measurement error, and actuation error are analyzed. The minimum fuel solutions for 17 typical cases are found, and designing rules for the rescue trajectories are developed. A multi-impulse Hill guidance scheme is presented for simultaneously realizing accurate rendezvous and saving energy. Simulation results reveal that the multi-impulse scheme is much more superior to the conventional double-impulse Hill guidance scheme in rendezvous accuracy and consumes nearly the same amount of fuel as the later does.

非线性系统的是目前自动控制理论研究的一个新热点，首先给出了近年来非线性系统理论研究基本结果的回顾，在此基础上，以非线性系统的鲁棒和鲁棒L2干扰掏问题为主线，概括介绍了基于耗散性的非线性系统鲁棒控制理论研究领域的一些新进展。