System Control Strategy on Floor Response Reproduction of High-rise Buildings Subjected to Earthquakes

Shaking table, known as earthquake simulators, is used to reproduce record of earthquakes. An original shaking table system is made up of an actuator, a servo valve, a controller, and rigid platform. By exciting an actuator, the response of specimens, which is mounted on the rigid platform, can be investigated in real time. However, causing to the stroke limit of the actuator, it’s difficult to reproduce floor responses of high-rise buildings which are subjected to earthquakes or long-period time histories. In order not to change the configuration of the shaking table, a passive transfer system with linear and nonlinear control strategy is used to enlarge the stroke limit of the shaking table, then the floor responses mentioned before could be reproduced. The linear controllers including feedforward control, PID control and LQG control are used to verify the feasibility and controllability of the passive transfer system. However, the transfer system which is made up of friction pendulum system contains a nonlinear factor related to damping ratio, causing to the poor reproduction of time histories. To improve the performance of passive transfer system, the nonlinear controllers based on the motion equation of friction pendulum system are introduced, including adaptive feedforward control, magnitude matching method and ξ-scheduling method. These methods mentioned above are verified by reproducing both floor responses of high-rise buildings which are subjected to earthquakes and sweep sine history, and the analysis of experimental result could be referenced for designing passive transfer system for different scale of shaking table systems.