Lyapunov based nonlinear impact angle guidance law for stationary targets

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Havacılık ve Uzay Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2015

Öğrenci: HAKKI ULAŞ ATEŞ

Danışman: ALİ TÜRKER KUTAY

Özet:

In modern guidance law designs, not only capturing but also considering a terminal impact angle while intercepting a target has become an increasingly important neccessity in modern guided systems. For several applications such as missiles systems, space explorations or aircraft docking, approaching the target with a specific impact angle is vital requirement for efficiency of the system. To achieve this requirement, a novel Lyapunov based nonlinear impact angle control guidance law for stationary targets is investigated in this work. In the proposed guidance law, nonlinear line-of-sight dynamics of the engagement geometry and kinematics between target and pursuer is studied and state equations for the line-of-sight angle and its rate are derived. The line-of-sight angle which converges the final flight path angle of the pursuer at the final rendezvous is aimed to be controlled to satisfy impact angle constraints. The nonlinear time-variant dynamics between target and pursuer is investigated.Then, to control robustly and stably, a first order sliding manifold to force the nonlinear dynamical system to exponential stability and reduce the order of the complex system is introduced. Moreover, Robust Control Lyapunov Function candidate is also investigated to control the dynamical system in order to head towards the desired sliding manifold. The neccesary acceleration commands to head towards the target with specified terminal impact angle is carried out by deriving control input of the nonlinear system to have asymptotical stability. Finally, the results of the proposed guidance law is expressed. Moreover, capturability analysis and capture conditions of the guidance law , robustness and disturbance rejection of the system is investigated. Furthermore, the response of the guidance law to some aspects which can be encountered in practical application is discussed.