Real-time hybrid testing of semiactive control strategies for vibration reduction in a structure with MR damper

Magnetorheological (MR) dampers have been widely studied and employed to solve the vibration problem in structures such as buildings and bridges. It is known that MR dampers can generate high damping forces with low-energy requirements and low-cost productions. However, the complex dynamics that characterize MR dampers make difficult the control design to achieve the vibration reduction goals in an efficient manner. In this paper, semiactive controllers based on the backstepping and quantitative feedback theory techniques are proposed and their performances are compared with each other on the problem of vibration control in a structure with an MR damper. They are applied to a large-scale three-story building with an MR damper at its first floor subject to seismic motions. The performance of the proposed controllers is experimentally evaluated by means of real-time hybrid testing scheme that accounts for time delays and actuator dynamics, allowing for the test of velocity-dependent devices.