Application of adaptive fuzzy sliding mode control to a seismically excited highway bridge

This paper presents an application of adaptive fuzzy sliding mode control (AFSMC) for a benchmark problem on a seismically excited highway bridge. This approach combines great advantages of sliding mode control (SMC), adaptive control and fuzzy control without compromising the stability or robustness. Switching-type control law of the conventional SMC and uncertainty part of the equivalent control is approximated by fuzzy controller to attenuate the chattering phenomenon of SMC and harmful effects caused by uncertainties. In order to reduce the complexity of the fuzzy rule bases, adaptive law based on Lyapunov function and Barbalat lemma is designed. AFSMC is also integrated with clipped-optimal strategy to illustrate its efficiency for semi-active MR dampers. Robustness of the AFSMC controller has been demonstrated analyzing +/- 30% perturbation in the stiffness of the bridge. Numerical results indicate that the response quantities of the highway bridge can be reduced to a satisfactory level superior to those of the sample LQG and LQG/clipped-optimal algorithms. Copyright (C) 2009 John Wiley & Sons, Ltd.