Adaptive sliding mode autopilot design for skid-to-turn missile model with uncertainties

Abstract

This paper presents an adaptive sliding mode controller for a skid-to-turn missile model with uncertainties. It is assumed that missile velocity, aerodynamic parameters and dynamics are non-constant or fast-varying. Although a general sliding mode controller inherently robust in this situation, the performance of a general sliding mode control scheme is not good if the aerodynamics parameter and the center of gravity position are not exactly known whereas the adaptive controller estimates some uncertainties, such as the aerodynamics parameter and the center of gravity. Therefore, the sliding mode control scheme and the adaptive control scheme are combined to ensure the performance. To verify the proposed nonlinear controller, numerical simulations are performed for a missile which is maneuvered widely in various scenarios. The proposed adaptive sliding mode control scheme has comparatively better performance than other control scheme. This claim is substantiated through the simulation of the Skid-To-Turn (STT) missile model whose aerodynamic parameters and dynamics are suddenly changed during the boost phase.