| Summary: | 碩士 === 淡江大學 === 土木工程學系 === 90 === Recently, the application of active structural control to seismic-excited civil structures has been broadly investigated. To justify the applicability of active control to actual structures, a 1:8 scaled model of the 3-story rigid frame building equipped with an active mass driver (AMD) device at the top floor was constructed on the shake table of the Institute of Civil Engineering, Tamkang University. Due to the unavailable information of seismic-induced response of structures in the practical situation, the system identification of the nominal system for the control law design is conducted by using only the response information from the excitation of the AMD device. By utilizing the curve-fitting technique for the transfer functions of response excited by the AMD device, the so-called control-structure interaction (CSI) is taken into account in the identification process. The advanced control strategy, Linear Quadratic Gaussian (LQG) method, is used to design the control law for achieving the control objective of reducing the interstory displacements and absolute accelerations of the building simultaneously. Consequently, a dynamic output feedback equation using the measurements of absolute accelerations as feedback quantities is formed for the on-line computation of the control command.
For the experimental verification, a LQG controller was designed and implemented to the scaled building model on the shake table and the experimental results under the excitations of El Centro (PGA=0.1g) and Kobe (PGA=0.1g) earthquakes were obtained. From both the results in the time domain and frequency domain, the control performance of the LQG controller is found to be quite effective if appropriate control parameters (weighting parameters) were chosen. Furthermore, the results from numerical simulation also show the satisfactory correlation with the experimental results. Therefore, the applicability of active control using acceleration feedback to a civil engineering building was successfully verified through the shake table tests.
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