非線性速度回饋控制於可變摩擦隔震結構之參數研究

Abstract

本研究所選用已開發之隔震系統為槓桿式可控摩擦阻尼器(Leverage-type controllable friction damper，LCFD)，此一半主動隔震系統可即時透過改變槓桿支點之位置，進而運用槓桿原理之轉換，以達到等效摩擦阻尼力之控制成效。過去研究中顯示適當的控制律搭配LCFD機構能夠有效降低結構動態反應，其中又以抑制結構位移為主；本研究中選用兩個控制律進行數值模擬分析，一為過去研究已開發之控制律「雙段速度控制律」，另一為提出新型之「ABS型速度控制律」；前者乃參考比例位移控制律之構想設計而成，而後者則是根據ABS剎車之應用概念達到隔減震之功能。兩者控制律皆僅須回授結構相對於地表之速度，於數值模擬分析方面運算式子簡易。而在研究中亦針對雙段速度控制律進行結構動態最大反應之參數最佳化探討，佐證過去提出之初始值已具有一定之控制並再針對參數進行些微調整。而經由數值分析顯示確實仍可達到雙段控制之隔震效果，於小地震時以減緩結構加速度為目標，而於大地震時則轉以抑制結構位移為主。而於ABS型速度控制律，其與各控制之數值比較下仍保有一定之雙段控制效果；且與雙段速度控制律比較下亦可發現其能於中型地震中更有效降低最大結構加速度值，並同時保有不錯之結構位移反應值，於結構反應之控制方面更能提供LCFD良好之隔減震成效。

A developed isolation system called Leverage-type controllable friction damper (LCFD) is used in this research, which could change the position of lever pivot in time to alter the equivalent friction force by using the principle of lever. The past research result proves that LCFD combining proportional displacement control (PDC) could reduce structural response especially for structural displacement under earthquake excitation. Two control law are used to combine with LCFD in this research, first of all the Bi-gradation velocity control (BGVC) which is based on the PDC, then the Anti-braking system velocity control (ABSVC) which is based on the ABS concept. Both control law only requires the structural velocity to calculate the equivalent friction force. The research also optimizes two parameters of BGVC to improve the result. The numerical result displays that the control law combining LCFD could reduce the response of structural displacement under major earthquakes, and retard the response of structural acceleration under minor earthquakes. The research also use ABSVC to compare with other type of control law, indicating that ABSVC could reduce much more the response of structural acceleration in far field earthquakes than BGVC.