A robust control method for seismic protection of civil frame building

Recently, more and more experimental studies indicate that a mature active control design toward practical implementation requires consideration of robustness criteria in the design process, which includes the performance robustness in reducing tracking error and in resistance to external disturbance and measurement noise, and the stability robustness with respect to system uncertainty. In this paper, a robust control method employing these robustness criteria that can be further converted to a generalized H∞H∞ control problem is presented for control of civil structures. To facilitate computation of H∞H∞ controllers, an efficient solution procedure based on linear matrix inequalities (LMI), the so-called LMI-based H∞H∞ control, is introduced. For verifying applicability of the proposed method, extensive simulations were conducted on a numerical building model with active bracings under seismic excitation, which was constructed from a full-scale steel frame building that was once tested on a shake table. In the simulation, system uncertainty is assumed in the controller design and the use of acceleration feedback is emphasized for practical consideration. From the simulation results, it is demonstrated that the performance of H∞H∞ controllers proposed is remarkable and robust, and the efficiency of LMI-based approach is also approved. Therefore, this robust control method is suitable for application to seismic protection of civil frame buildings.