Optimal nonlinear tracking control for btt missiles using polynomial feedback

Abstract

Abstract It is well‐known that bank‐to‐turn (BTT) control offers potential improvement in missile performance. For a highly maneuverable bank‐to‐turn missile, the dynamics of the pitch, roll, and yaw axes are not only cross‐coupled but also nonlinear, especially when high roll rates are involved. However, most BTT autopilots proposed to date rely on linear methods, either the classical SISO techniques or the state‐space methods of modern control theory. These linear approaches restrict their applicability to either small or slowly varying roll rates. The unmodelled effects of severe non‐linearities inherent in missile dynamics, particularly for asymmetric air‐frames, still remain one of the most critical issues in BTT autopilot design. In this paper, an optimal nonlinear tracking control using polynomial feedback is developed for BTT autopilots. Numerical simulations based on a 6 DOF nonlinear missile model are presented to demonstrate the effectiveness of the proposed nonlinear control technique.