Research of trajectory and canard mechanism's design for two-dimension trajectory correction fuze

The two-dimension canard trajectory correction fuze technique is a new concept fuze technique with an added two-dimension canard trajectory correction subsystem on the fuze. It can control the range and direction of the projectile's flying trajectory and reduce disperses of them as well. The primly task, in the process of the trajectory correction fuze design, is determining the control starting point according to the correction capacity and designing the trajectory with the minimum energy cost. Actually trajectory correction is how to choose the control rule to realize the control process from the control starting point to the target point. The paper optimizes correction trajectory with Pontryagin's maximum principle and analyzes optimal control variable's fit. The necessary maximum overload can be calculated by the range's maximum correction capacity of the correction trajectory, while the usable overload can be calculated by the necessary the overload and margin. The usable overload, which is determined by the aerodynamics shape of canard surface and the canard partial angle, is the symbol of the canard mechanism's correction capability and the key control element of the projectile. The better flexibility index for the projectile can be obtained with a larger canard aerodynamics shape and the usable overload of canard partial angel. But the canard surface can only provide limited overload because the limitation of fuze room and the projectile's flying stability. When the canard partial angel reaches a certain value, the angel has little influence to the overload value, so it also offers a limited overload value. Based on the usable overload value, the canard according with velocity can be designed to carry out the trajectory correction and improve the strike precision.