地震模擬振動台之控制設計與性能驗證

Abstract

本研究提出地震模擬振動台之控制設計與性能驗證。由於世界各地強震災害頻傳，為提升地震工程研發能力，故需致力發展出低成本、高可靠度、高效率之即時動態測試方式。交通大學地震模擬振動台於民國86年完成，近年來由於設備老化，導致振動台性能表現並不穩定。為改善振動台之性能表現，本研究提出在原有的油壓及控制系統之下，另以dSPACE控制系統進行外迴路控制，並開發即時控制介面以利操作，完成振動台升級目標。振動台性能表現之驗證係由參考訊號與達成之位移歷時、加速度歷時的峰值與均方根值進行比較，並以兩者之相關函數及頻譜的同調函數作為性能指標檢驗控制表現。測試結果顯示，吾人給定兩組不同的地震以及五組振幅，無論振動台是否搭載試體，加入外迴路控制者均較僅由內迴路控制表現更優異。升級之振動台可提供本系地震工程研究更精確、穩定的測試環境。

This study proposes the control design and performance verification of an existing seismic shake table. As disastrous earthquakes have been increasingly occurring worldwide, there is a need to develop low-cost, reliable and efficient real-time dynamic testing methodology for advanced earthquake engineering research. The NCTU seismic shake table was built in 1997 and its performance has become deteriorated due to aging problems over the years. As an effort to improve the performance of the shake table, this study proposes to integrate the current hydraulic and control system (MTS 407) with the dSPACE controller for auxiliary outer-loop control. Moreover, a control interface has been developed to facilitate on-line operation of the table. Performance of the shake table is verified by comparing the reference and achieved signals of displacement and acceleration time histories in terms of peak value, and root-mean-square error. The control performance is also examined by comparing their cross correlation functions and coherence functions. The test results of two earthquake scenarios with five intensity levels indicate that the system performs better with outer-loop state feedback control, regardless of bared table or testing specimen loaded. The upgraded shake table may provide a more accurate and stable testing environment for earthquake engineering research.