Design a of 3-Dimensional Nonlinear Optimal Robust Guidance Law for Homing Missiles against Maneuvering Targets Using Genetic Algorithm

Optimal sliding mode guidance (OSMG) law is proposed for tactical missiles which is pursuing maneuvering targets in three-dimensional space. The most important characteristic of sliding mode control (SMC) is high robustness against parameter variations or external disturbances. By using a Lyapunov function, it is demonstrated that the derived guidance law can stabilize the engagement system. Also, coefficients of controller are chosen using genetic algorithm optimally. Compared with traditional augmented proportional navigation guidance (APNG) law, the proposed guidance law not only can increase robustness against external disturbance and eliminate the effect of target maneuvers but can improve tracking performance and reduce interception time and miss distance. 3-D missile-target engagement is simulated for different target maneuvers and for some various scenarios, then results of the OSMG law are compared with conventional APNG law. Simulation Results confirmed the above mentioned pretensions.