Comparison of LQR and H1 Algorithms for Vibration Control of Structures in Seismic Zones

This paper presents the ndings of a study devoted to a comparison of the eeective-ness of Linear Quadratic Regulator (LQR) and H 1 control for structures subjected to earthquake loadings. Research in the eld of active structural control has received much attention over the past few years, with the majority of eeorts focusing on formulation and application of the LQR-based control algorithms. Because of various drawbacks associated with the LQR algorithms, such as inability to account for time variant structural properties and the time history of the loading, other control algorithms such as H 1 have been investigated as viable alternative control algorithms for application to civil structures. In this study, a comparison is made between the LQR and H 1 algorithms based on application of each algorithm to an actively controlled 33-story structure. This structure , located in Tokyo, is equipped with two rooftop active mass dampers (AMD's) capable of eeectively increasing damping and controlling vibratory behavior in four vibration modes. Comparisons of the control algorithms are performed on shear building representations ((ve degrees-of-freedom) of the structure. Both actuator eeort and vibration reduction under small to medium earthquake excitations are considered in this discussion. Additional studies are performed to investigate the robustness of the control scheme considering non-linear actuator saturation eeects and time varying uncertainties in the structural parameters.