ABSTRACT
The aim of structural control is to reduce seismic vibration by supplying adequate counterforce by means of changing the stiffness and/or altering the damping with the help of external active, passive, or semi-active devices to prepare a building for sustained use. In this chapter, the semi-active control scheme has been studied due to its advantages over the active and passive control schemes. For example, the semi-active control schemes use less power and yet provide performance at par with active control schemes and the stability of passive control schemes. A sustained building requires an apt controller to dispense the appropriate control signal to the magnetorheological damper (MRD) for seismic vibration mitigation. The proper selection of a controller depends on the non-linearities present in the semi-active device, available feedback measurements, and the number of devices implemented in the structure. A few controllers like the passive ON/OFF, double-output feedback polynomial controller (DOFPC), the simple passive controller (SPC), the Lyapunov stability criteria-based controller, the clipped-optimal linear quadratic regulator/linear quadratic Gaussian (CO-LQR/LQG) controller, the quasi-bang-bang controller (QBB), the modified quasi-bang-bang controller (MQBB), and the classical proportional-integral-derivative (PID) controller have been implemented and studied in this chapter. These controllers are developed to be used with MRD and evaluated for their performance on a benchmark three-story prototype structure subjected to different seismic excitations. It is observed that the controllers keep on providing the command signal to the MRD without considering the maximum capability of the MRD, unlike the CO-LQR and LQG. The later controllers compared the current output of the MRD with the previous output and calculated the command signal for the MRD, delivering better results.
