Instantaneous Optimal Control of Seismic Response Using Magnetorheological Damping

Abstract

Instantaneous Optimal Control (IOC) is used to obtain desired force from MR damper fitted to a seismically excited building. Excitation is considered when minimizing performance index, unlike in classical optimal controllers. Modified Bouc-Wen damper model and on-off voltage law is considered. Various forms of state weighting matrix are considered for controller design. IOC is compared with Linear Quadratic Regulator(LQR), Linear Quadratic Gaussian(LQG) and Passive-on control. It yields reduction in: maximum peak and maximum RMS interstorey drift; and generally in accelerations vis-a-vis LQR and LQG. IOC Riccati Matrix Type controller appears most effective, yielding: lowest maximum peak drift and maximum peak acceleration and generally best storeywise drift control vis-a-vis passive-on, LQR and LQG; substantially lower peak accelerations vis-a-vis LQR and LQG.