Global adaptive fuzzy dynamic surface control of strict-feedback systems

The paper presents a global tracking fuzzy control design for strict feedback systems with unknown control affine nonlinearities. In particular, the so-called explosion of complexity problem alleviated via using a modified dynamic surface control (DSC) technique. The modification mainly involves a first-order filter with a space-modulated input, which in turn ensures the boundedness of the filter states. However, the repeated differentiations in the auxiliary robust controller remains as the price of preserving the global stability. Nevertheless, since the adaptive fuzzy controller dominates most of the time, the overall controller still significantly improves the existing global designs in terms of computation and implementation. Simulation results are provided to demonstrate the validity of the proposed scheme.