Discrete-time fuzzy variable structure control for buildings with delay time in control

The undue chattering effect is the major disadvantage of conventional variable structure controllers. Therefore, based on the advantage of the fuzzy logic control, we propose a new discrete-time fuzzy variable structure control method that can not only reduce seismological response but can also avoid undue chattering effect. Considering the time delay effect, in the presence of time delay, the motion equation of the discrete-time control system is transformed into standard discrete form which contains no time delay by augmenting the state parameters. Finally we give numerical simulations for MDOF (Multiple-Degree-of- Freedom) shear building model containing an active brace system. The results of numerical simulations have been presented in graphical and tabular form, and the effectiveness of the proposed control method has been compared with that of the conventional discrete-time variable structure control method.