(A) study on the range extension of gliding artillery ammunition using trajectory optimization

Abstract

This thesis proposes range extension of gliding artillery ammunition using trajectory optimization. The study focuses on a range extension of gliding ammunition after reaching the maximum altitude with predetermined firing condition. The initial projectile trajectory of the gliding ammunition is determined by gun, propellant and firing condition as in conventional ammunition. Before reaching its maximum altitude, the glide wing of gliding ammunition is folding for firing. The gliding ammunition deploys its tail fins to stabilize and deceleration its initial spin on after firing, which is called as transition phase. It loses its velocity and maximum reachable altitude during transition phase. The gliding ammunition is new concept of ammunition that performs guided flight using its tail fins and a main wing after entering its maximum altitude. First, a conceptual model of the gliding ammunition is designed with consideration of its dynamic characteristics. The aerodynamic coefficients of the gliding ammunition are calculated for flight simulation. The aerodynamic coefficients of ballistic flight is estimated from PRODAS and aerodynamic coefficients of guided flight is obtained from Missile DATCOM. The six degree-offreedom dynamic model is designed in MATLAB and verified through comparing the results from PRODAS. In guided flight phase, the dynamic characteristics of gliding ammunition are similar to that of glider without thrust. A key for extending its range is to control the gliding ammunition with maximum lift-to-drag ratio. Hence, the optimal command of angle of attack is calculated from optimization solver to acquire its maximum lift-to-drag ratio. The optimized angle of attack control command is converted to the normal acceleration command used for the missile control. The acceleration command is input to the 6 DOF kinematic model through the autopilot. The gain of the autopilot controller is tuned with gain scheduling method. Finally, the range of gliding ammunition with range extension using optimized acceleration command is compared with the gliding ammunition with general ballistic flight.