Multimode vibration control for a flexible building structure using H-infinity based robust control

This paper proposes a method of controlling the vibration of a flexible structure using H-infinity control theory. For this purpose, two reduced order lumped mass models, expressed by 5-DOF systems each, are derived. These models are derived by considering the five vibration modes along the x and y direction respectively and neglecting all the other higher frequency modes. Neglected vibration modes are regarded as unstructured uncertainties and taken care of at the time of the design process. The dynamic output feedback controller is designed based on the reduced order model and the approximate knowledge of the unmodeled system uncertainties. The first five vibration modes of the structure along the x and y directions are well suppressed using two newly proposed actuators (dynamic vibration absorbers) without any spillover problem. The control algorithm is verified through simulation and experimental studies.