Fuzzy aided baseline controller for active vibration control of non-linear hysteretic base isolation buildings

Base isolation is one of the most widely accepted techniques in structural control to protect structures from strong earthquakes. Structural control problems normally deal with nonlinear behavior of base isolators, uncertainties in the base isolated system models and limited state measurements. Fuzzy models can be regarded as flexible mathematical structures that can approximate a large class of complex nonlinear systems to a desired degree of accuracy. In this paper a fuzzy aided baseline controller (BLC) is proposed for active control of a benchmark nonlinear base isolated building. The fuzzy rules are generated from the numerical data and with a priori knowledge about the variations of base acceleration and base displacement with respect to the applied control force. The Proportional-Integral - Derivative Controller (PID) is considered as BLC and the gain parameters are tuned using Genetic Algorithm. Simulation studies have been carried-out using the full-scale three dimensional benchmark eight-storey building comprising of hysteretic base-isolation subjected to a set of four near-fault earthquakes. The performance of the proposed control scheme is measured in terms of a comprehensive set of performance indices. The performance of the proposed controller is compared to other controllers reported in the literature. The results clearly show that the proposed controller is effective in suppressing the structural vibrations.