Sliding mode controller along with feedback linearization for a nonlinear missile model

The traditional three-loop autopilot as presented by Zarchan suffers from coupling in pitch, yaws, roll channel as well as degraded performance due to huge aerodynamic uncertainties. Sliding mode control is applied to design autopilot for skid-to-turn missile (STT) missile systems to overcome the above stated difficulties. The design has two steps. The first step involves feedback linearization and the second stage is to design the sliding mode controller. A comparative simulation results based on a missile model shows the improved performance of the autopilot obtained with this controller over the traditional one. Lastly a nonlinear observer is presented that estimates the required states for feedback linearizing control