A Spiral-Maneuver Control Method for a Fixed-Trim Warhead

Given the problem that the common spiral-maneuver control method to realize both vertical and lateral overload needed is not applicable for a fixed-trim warhead with a controllable lift-force direction but an uncontrollable magnitude, a new spiral-maneuver control method is proposed for a moving-mass fixed-trim warhead in the control mode of single rolling channel. Firstly, the relative motion model is formulated with the spiraling angle and spiraling angular velocity. It is an intuitional description of the spiraling motion. Based on the relationship of the spiraling motion variables and angular rates of light-of-sight, the spiral-maneuver command is designed to ensure that the angular rates of light-of-sight converge to zero at the end. The back-stepping control method is then applied in the integrated guidance and control of the mass-point motion and the rolling attitude motion. The bank angle is controlled by a one-dimension moving mass to adjust the direction of the lift force. Thus, there's a component of the lift force controlling the angle between the relative velocity vector and the line of sight to trace the desired spiraling angle, while the rest component results in a spiraling angular velocity with an invariable direction. Numerical simulations demonstrate that the proposed spiral-maneuver control method is effective for a fixed-trim warhead in the mode of single rolling channel control. It is simple and potential to be used in engineering.