Design Of Cooperative Guidance Laws With Constraints On Impact Time And Terminal Angles

With the development of modern anti-missile technology and electromagnetic jamming technology, military countries are committed to developing and improving their anti-missile systems, defense systems with comprehensive integration have been gradually formed. As a result, the penetration with single missile is faced with more severe challenges. For anti-ship missiles, besides the research on new technologies to improve missiles’ maneuverability, stealth, jamming immunity, cooperative attack strategies of multiple missiles also draw much research attention. The key of cooperative attack strategies is to realize that multiple missiles attack the target with the specific attack angles at the same specified time. So guidance laws must be designed under constraints on impact time and terminal angels. The research on this problem is carried out in this dissertation and the main contributions are as follows.Firstly, three-dimensional mathematical models for the guidance problem were constructed and the cooperative guidance problem with constraints on impact time and terminal angels was described. Then the design problem of the cooperative guidance law was formulated as a nonlinear optimal control problem with fixed terminal time and terminal state constraints. As one of the constraints was unable to realize, the optimization problem cannot be solved directly. Then the missile-target relative motion model was established to transform the optimization problem equivalently to an optimal control problem which is solvable. This preliminary work laid the foundation for the further research on the guidance design problem.Secondly, the optimal control problem was solved by direct method. Above all, the optimal control problem was transformed to a nonlinear programming problem by Gauss pseudospectral method. Then the nonlinear programming problem was solved by sequential quadratic programming. Solving a quadratic programming sub problem was proved to be equivalent to solving the original problem, and a general form of sequential quadratic programming algorithm was proposed. Then the global convergence and the superlinear convergence of this algorithm were proved. Maratos effect was analyzed and corresponding countermeasures were proposed.Thirdly, the predictive control theory and receding horizon control method were used to implement the designed optimal guidance law in a closed-loop way. The shortcoming of the open-loop guidance law was overcome so that strong robustness and anti-jamming were acquired. Model predictive control method was introduced and then used to implement the designed optimal guidance law. Then the existence and uniqueness of the optimal feedback law and the global stability of receding horizon feedback system were obtained.Finally, simulations of the guidance law were carried out and the simulation results verified the feasibility and effectiveness of the proposed method.