Fault-Tolerant Fuzzy Sliding-Mode Control For a Class of MIMO Underactuated Nonlinear Systems

Abstract : This paper focuses on the synthesis of adaptive fuzzy fault tolerant controller which combines a sliding mode controller and a Proportional Integral controller (PI) for a class of MIMO underactuated nonlinear systems with external disturbances. The proposed control law treats the underactuated systems on their original non square form without squaring them by adding or eliminating variables. The uncertain system functions are predicted by fuzzy logic systems and free parameters can be updated on-line by adaptive laws based on Lyapunov theory. The overall adaptive fuzzy sliding mode scheme guarantees the global stability of the resulting closed-loop system as well as the convergence of the reference tracking error vector. The validity of the proposed approach is shown by computer simulations.