Nonlinear output feedback control for seismic-excited linear structures

An optimal nonlinear controller, which is polynomial in the states, has been proposed earlier for applications to seismic-excited buildings. Such an optimal polynomial controller has been demonstrated to have significant advantages over the linear optimal controller for limiting the peak dynamic response of the structure. In this paper, a nonlinear static output feedback controller corresponding to the optimal polynomial controller is proposed. The nonlinear static output feedback controller utilizes only the information measured from a limited number of sensors installed at strategic locations, without an observer, thus facilitating practical applications of active/hybrid control systems to civil engineering structures. Significant advantages of the proposed nonlinear static output feedback controller over the linear one, in terms of the load-adaptive capability for limiting the peak response of the structure and required control energies, are demonstrated by simulation results