A novel robust optimum control algorithm and its application to semi-active controlled base-isolated structures

A new Robust Optimum control algorithm that combines a Linear Quadratic Regulator and a nonlinear robust compensator is presented to improve the control of the seismic response of building structures with nonlinear isolation systems. The Linear Quadratic Regulator was used to achieve the optimal performance of a nominal linear model of the controlled structure, and a robust compensator was developed to restrain the effect of nonlinearities. The Robust Optimum control method was proven theoretically, and implemented to control the response of a base-isolated structure equipped with a Tunable Friction Pendulum System isolation under different ground motions. The simulation results validated the stability, robustness, and generalization ability of the proposed control algorithm, and suggested that it is effective in controlling base isolation displacement, inter-story drift, and floor acceleration. The designed robust compensator can successfully compensate for the effect of nonlinearities.