飛彈攔截與小行星登陸之非線性導引控制

Abstract

本論文主要在研究歸向飛彈之攔截與小行星登陸問題之強健性導引律分 析與設計。首先，我們利用 里阿普諾夫方法(Lyapunov approach) 來分析在線性回授導引律下飛彈攔截系統穩定 性的 問題。但在考慮有外界干擾及實際的工作條件下，此一導引律並無法滿足 需求。因此，我們 利用滑順控制對於外界雜訊具有強健性的特性 ，提出了一種可變結構控制的方法，期望對雜 訊具有抑制的 功能。此外，我們並提出另一種以回授線性化的導引律與可變結構控制的 導引律做比較。利用數值模擬分析，我們在時域上對攔截時間及燃料損耗 等兩項指標作一 綜合性的探討。從模擬結果得知，不論在 飛彈攔截或小行星登陸問題上， 以回授線 性化的控制方法所設計的導引律明顯的能夠獲得較佳之性能表現。 In this thesis, we study the problems of missile interception and soft landing on an asteroid. First we employ linear stability theory to design guidance control laws for missile interception problem. Lyapunov approach is then used to enlarge the capture region. However, for the case of large capture distance and/or maneuvering target, such a guidance control law is found to fail to intercept the target. Variable structure control type guidance laws are proposed to tackle the problem. This is achieved by treating the maneuver motion of the target as unmodeled dynamics and suitably selecting the sliding surfaces. Moreover, feedback linearization type control laws are also proposed for missile interception. These two control schemes are shown to be effective in intercepting both non-maneuvering and maneuvering target. Same approaches are then employed to design the guidance control laws for the soft-landing on an asteroid. The main difference between interception and landing problems is that both aero-drag and gravitational force are concerned in landing problem but not in missile interception. Numerical simulations are presented to demonstrate the main results, which show that feedback linearization type guidance control laws provide better performance in both missile interception problem and the soft landing on an asteroid.