An improved semi-active structural control combining optimized fuzzy controller with inverse modeling technique of MR damper

An effective and robust semi-active control scheme using MR damper for mitigating the earthquake-induced structural responses is proposed in this study. In the first place, a human-designed fuzzy logic controller is developed, in which the uniformly distributed membership functions are adopted for both input and output variables, and the fuzzy rules are formulated based on the law of the fundamental vibration mode. Next, an inverse modeling technique is developed for identifying the input current of MR damper based on the modified Bingham-plastic model. To simultaneously mitigate the seismic responses and guide the MR damper selection, the multiobjective NSGA-II-based approach is applied. The human-designed fuzzy logic controller is then optimized, in which the parameters in the output variable range, membership functions, and the rule base are defined as the design variables. By taking into account different parameter combinations, a variety of Pareto-optimal solutions are derived, based on which the influences of the membership function’s type and symmetry, as well as the rule base’s symmetry on the control performance, are analyzed. Finally, the improved semi-active control systems have been constructed for both linear and nonlinear structures by combining the optimized fuzzy controller with the proposed inverse modeling technique of MR damper. Numerical results have demonstrated the effectiveness and robustness of the proposed semi-active control scheme to the uncertainties associated with structural properties and seismic excitations.