Research On Guidance Method With Terminal Impact Angle Constraint

With the rapid development of the missile technology in modern warfare, the assault of air-to-land missile has became the focus of research and devopment of avigation weapons. To obtain a better kill effect of the warhead of missiles, many kinds of missiles are expected to get not only a minimum miss-distance but also a desired terminal angle. Most current guidance laws with terminal impact angle constraint can not satisfy the guidance mission, therefore it's necessary to perform research about the guidance laws which has the special mission. In this paper, the missile guidance with terminal impact angle constraint and integrated guidance and control design for missile with terminal impact constraint were researched.Firstly, the mathematical model of the missile on z-y-x transformation frame was constructed. Based on the requisite reference frames and transform relation of reference frames, the translational dynamics equations,the rotational dynamics equations,the translational kinematical equations and the rotational kinematical equations were given. The research work lays the groundwork for the successive researches.Secondly, the sliding mode guidance method with terminal impact angle constraints was studied. The sliding mode guidance law of miss distance with impact angle constraint was presented; aimed at fixed target and maneuvering target, sliding mode guidance laws with both missile distance constraint and terminal impact angle constraint were inferred. The methods for determining the error coefficient of angle,the coefficient of reaching law and the coefficient of on-off item were also developed respectively; the proposed performance of guidance laws were thereafter analyzed; and the methods for estimating relative distance between the missile and target, and the method for estimating acceleration of target are proposed respectively. The simulation results showed the validity of this guidance method.Thirdly, the backstepping guidance method with terminal impact angle constraint was studied. Based on backstepping and Lyapunov stability theorem and estimation about time-to-go, the guidance law with constraints on both missile distance and terminal angle was proposed; the proposed guidance law was proved to be able to meet the requirements of missile guidance. Method for estimating time-to- go of missile was further given. The simulation results showed the validity of the backstepping guidance method.Finally, integrated guidance and control method with terminal impact angle constraint was researched. The mathematical model of an integrated guidance and control model in pitch and yaw plane were established on z-y-x transformation frame; and then nonlinear transformation was employed to transform the mathematical model into a standard form suitable for sliding mode control method design; a sufficient condition for the existence of linear sliding surface was given in terms of LMI, based on which the corresponding reaching motion controller was developed. The proof was further given that integrated guidance and control method with terminal impact angle constraint could hit target while maintaining the robust state of a missile and satisfying the terminal angle constraint. The simulation results showed the validity of the proposed method.The research work provided an effective solution for guidance with terminal impact angle constraint and integrated guidance and control with terminal impact angle constraint, laying the foundation for further research of terminal impact angle constraint.