ABSTRACT
This chapter discusses active control of adaptive structures against seismic ground motions. The non-autonomous control problem is reduced to intermittent autonomous controls in the structure by means of active base isolation. Control of an active base isolation system is basically an openloop control problem. The chapter discusses only the active base isolation systems. In isolating structures against horizontal seismic excitations, seismic base isolation pads are widely used. In areas of high seismic activity, when it is feasible, many older building structures are retrofitted with these pads. The chapter also discusses actuator placement problem for the active base isolation systems for seismic ground motions. It describes control energy, control system, and control law for active base isolation systems. The control system consists of two parts, an open-loop, one representing a feedforward control for the base isolation system, and a closed-loop, one representing a feedback controlfor the structure.
