| 摘要: | 本研究將兩組單向天鉤主動隔震系統以正交堆疊的方式，擴展為一套雙向天鉤主動隔震系統，以應對雙向地震輸入。因正交假設兩向完全獨立，使用單向天鉤主動隔震系統並考慮衝程限制，詳細列出其運動方程式和控制律，進行數值模擬和簡諧震波實驗驗證。天鉤主動隔震系統參考傳統天鉤控制理論，改良主動控制力之計算，調整為回饋訊號基於系統相對地表速度，且前饋訊號為積分濾波後的地表速度，形成混合前饋回饋系統作為控制。此設計提高訊號測量的便利性和穩定性，並考慮系統固有阻尼的影響。此外，於系統中引入控制力濾波器，以濾除非預期之高頻訊號，並將其擴展為包含積分濾波器和控制力濾波器的形式，考慮濾波器的影響進行最佳化設計。改良之主動控制力為非全狀態回饋，因此採用直接輸出回饋，目標是最小化系統絕對加速度，並通過參數迭代更新進行控制力增益參數的最佳化設計。針對衝程限制問題，通過降低地表速度增益參數進行初步控制，當位移增大到一定程度時，在主動控制力中引入衝程限制力以進一步控制系統位移。首先，進行設計阻尼比參數分析以確定隔震系統的最優設置參數。對系統進行特徵分析，施加主動控制力將固有頻率遠離地震主要頻率範圍，減少共振。通過頻率反應函數和地震歷時分析，證明天鉤主動隔震系統的隔震效果優於被動隔震系統。穩定性分析顯示，相對地表速度增益參數的變化會影響系統穩定性，而地表速度增益參數的變化則不會，因此可用來調整系統衝程位移。時間延遲穩定性分析確認主動控制力延遲時長對系統穩定性的影響。引入衝程限制控制律並進行地震歷時分析，結果顯示該系統在最佳隔震效果下有效減少衝程位移，保護隔震系統。為了驗證數值模擬的結果，本研究利用振動台進行簡諧震波試驗，驗證實驗數據與分析結果呈現相似趨勢。此外，地震震波經由構架反應後的樓板加速度具有不同於震波本身的特性，由於該系統主要給予高科技廠房中的重要儀器提供隔震保護，因此所承受的應為樓板加速度。為了更貼近真實應用情境，對系統進行樓板加速度歷時分析。結果顯示，天鉤主動隔震系統在樓板加速度作用下仍表現出顯著的隔震效果，且考慮衝程限制的系統在保護衝程方面也有效果。;This study expands into a bi-directional skyhook active isolation system by orthogonally stacking two sets of unidirectional skyhook active isolation systems to address bi-directional seismic inputs. Due to orthogonality, two directions can be assumed to be completely independent. Using unidirectional skyhook active isolation systems and considering stroke restraint, the equations of motion and control laws are detailed for numerical simulations and harmonic wave experiment validation. The skyhook active isolation system is based on traditional skyhook control theory, with improvements in calculating active control forces. The design adjusts feedback signals based on the system′s relative ground velocity and feedforward signals as integrated filtered ground velocity, forming a hybrid feedforward-feedback control system. This design enhances the convenience and stability of signal measurements and considers the impact of the system′s inherent damping. Additionally, a control force filter is introduced to remove unexpected high-frequency signals. The system is extended to include integral filters and control force filters, considering their impact during the optimization design process. The improved active control force is non-full-state feedback, thus direct output feedback is adopted. The goal is to minimize the system′s absolute acceleration, and control force gain parameters are optimized through parameter iteration updates. To address stroke restraint, initial control is achieved by reducing ground velocity gain parameters, and when displacement increases beyond a threshold, stroke restraint forces are incorporated into the active control force for further displacement control. Firstly, design damping ratio parameters are analyzed to determine the optimal settings for the isolation system. The system′s characteristics are analyzed to apply active control forces, shifting natural frequencies away from the dominant earthquake frequencies and reducing resonance. Frequency response functions and seismic time-history analyses demonstrate that the skyhook active isolation system outperforms passive isolation systems in seismic isolation. Stability analysis shows that variations in relative ground velocity gain parameters affect system stability, while ground velocity gain parameter variations do not, allowing for stroke displacement adjustments. Time delay stability analysis confirms the impact of active control force delays on system stability. Introducing stroke restraint control laws and conducting seismic time-history analyses reveal that the system effectively reduces stroke displacement while achieving optimal isolation effects, thus protecting the isolation system. In order to validate the numerical simulation results, harmonic wave experiments were conducted using a shaking table, verifying similar trends between experimental data and analytical results. Furthermore, considering the different characteristics of floor acceleration responses from seismic waves post-structure interaction, the study conducts floor acceleration time-history analysis for a more realistic application scenario. Since the system is primarily used to provide isolation protection for critical instruments in high-tech factories, it is subjected to floor acceleration. Results show that the skyhook active isolation system maintains significant isolation performance under floor acceleration effects, and systems with stroke restraint effectively protect against excessive displacement. |
