Direct adaptive fuzzy sliding mode control with variable universe for near space vehicle

The design of variable universe direct adaptive fuzzy sliding mode control law to a class of uncertain nonlinear systems is considered.According to the tracking error,the contraction and expansion factors of variable universe fuzzy controller are tuned on-line,so the nonlinear part is estimated by the fuzzy system.Robust controller is constructed to attenuate fuzzy approximation errors and enhance the whole system performance.The adjusting law of the adaptive parameters is given.By using Lyapunov theory,it is proven that the closed-loop is uniformly stable.Finally,the flight control system of near space vehicle(NSV) under hypersonic condition is designed by using the proposed method.The results show the fine performance of the method.