Backstepping-based Adaptive Fuzzy Sliding Mode Control for Autopilot Design

A backstepping approach, combined with adaptive fuzzy sliding mode control, is used to design a missile autopilot in this paper. The proposed scheme separated the plant into two subsystems, such that single controllers can be designed and therefore the stability of entire system is reached automatically. The single control laws are designed using sliding mode control based on the Lyapunov stability theorem, and the adaptive law is derived to adapt the value of the lumped uncertainty in real-time. Moreover, with the universal approximation ability, an adaptive fuzzy system is used to approximate strong coupling nonlinear dynamics of the missile during large angle-of-attack flight and provide robustness to parametric uncertainties in the missile aerodynamics.