Adaptive sliding mode control for bank-to-turn missiles

This paper presents an adaptive sliding mode controller for bank-to-turn (BTT) missiles, which have the characteristics of strong coupling nonlinearity and non-minimum phase phenomenon. From a nonlinear multivariate model of air-to-air missile, a two-loop mathematical model is educed based on singular perturbation theory and time scales. We achieve fin commands for actuators via two-loop adaptive sliding mode control scheme under the assumption that the perturbation is bounded and the guidance commands are given. Moreover, we constitute a sliding mode disturbance observer to estimate the value of perturbation. With the perturbation well estimated, the practicability of the control scheme is guaranteed and the robustness of system is improved. Simulation with modeling error and external disturbance shows the validity of the control scheme. Tracking result is highly precise and the angle of sideslip is small, which satisfies the requirement of BTT control.