Robust controller design for a class of complex system based on two-step approximation with fuzzy logical system

Based on fuzzy logical system, a novel nonlinear robust adaptive control scheme is presented for a class of complex systems with uncertainties. The two-step approximation method is proposed to approximate uncertainties with fuzzy logical system, which is able to reduce the complexity of designing fuzzy logical system and circumvent the curse of dimensionality problem to a certain extent. A robust adaptive controller is designed using the Lyapunov theory, which is able to ensure both the states and the parameter estimate errors uniformly ultimately bounded (UUB). Our method is verified effectively by applying to inverted pendulum system.