Simple Three-dimensional-guided Bomb Optimal Variable Structure Guidance Law Studies

Simple guided bomb played a great role in modern warfare and the corresponding hardware and software should be updated. Based on the high precision, the guidance law should be robust to adapt to the environment changes. Guidance law improvement has faced with many challenges, such as improving the robustness, maintaining good attack posture, implementing concealed trajectory or avoidance and penetration since the combat environment is getting more and more complicated. Under this background, the moving target is taken into account when a discussion is devoted to studying the three-dimensional (3D) optimal and slide mode variable structure guidance law (VSG) under nonmaneuvering target, which aims at impact angular and precision constraints. Some theoretical and simulation results are presented. The main contents include:Firstly, based on the analysis of variable structure, 3D VSG with terminal multi-constraints are applied in simple guided bomb, which can overcome the defect that the PNG has difficulty in impact angular constraints. VSG can also improve robustness and be suitable for moving target.Secondly, 3D linear quadratic optimal guidance law (LQOG) is researched considering the conditions of impact angular and terminal rate of loss. The comprehensive performance of LQOG is optimal when the target is unmoving and its state is exactly recognizant.Finally, 3D optimal variable structure guidance law (OVSG) with miss-distance, impact angular and orientation angular terminal multi-constraints used in simple guided bomb is presented, which not only overcomes the drawbacks of LQOG's poor robustness and sensitivity to disturbance, but also can reduce the control authority requirements of pure sliding-mode. The method improves robustness precision and adaptability of simple guided bomb systems.As well as the theoretical analysis, the results of numerical simulation show the more satisfactory performances by OVSG than by other three guidance laws. This study can supply a reference for the applications in engineering.