時變懸臂梁結構振動控制

Abstract

，本文主旨在研究質量分布隨時間變化之懸臂梁結構的振動控制。時變系統沒有固定的自然頻率，所以控制電路必須能夠對特定頻寬下的振動同時控制才能有效的抑制振動。本研究利用壓電陶瓷材料之機械能與電能互相轉換的性質作為控制系統的感測器與致動器。壓電陶瓷材料可視為一電容電路，電訊號經過電容會產生相位變化，而回授訊號的相位即是本研究主要討論的問題。壓電感測器的輸出物理量為電荷，因此必須使用電荷放大器來放大感測訊號。實驗中以改變懸臂梁的質量分布作為時變系統，當時變懸臂梁結構開始振動，由感測器擷取振動訊號，將訊號經過電荷放大器反相放大後，回授輸入致動器中來抑制梁的振動。又由於不同頻率的振動訊號經過控制電路後會產生相位差，故加入相位補償電路來調整回授訊號的相位以提升整體振動控制效果；此外，亦針對回授訊號相位需求自行設計電荷放大電路，實驗結果顯示此時無須使用相位補償電路調整相位即可有效控制時變系統的振動。，

This research is aimed to study on the vibration control of a time-varying mass distribution cantilever beam. Since natural frequencies of a time-variant system are not constants, the controller of the system therefore is required to simultaneously minimize the excitation to a specific range of frequency. In this research, we apply the piezoelectric materials to be the materials of our senor and actuator due to their attributes of interchanging mechanical energy with electrical energy. The physical quantity of piezoelectric senor’s output is charge; a charge amplifier is therefore used for enlarging signal. When a time-varying cantilever beam vibrates, the senor receives its signal of vibration. The signal feedbacks to the actuator and executes a vibration control on the beam with being reversely amplified. Different frequencies of signal occur phase shifts while pass through the controller; hence, in order to improve the overall effects, we introduce phase compensation circuit to adjust the phase of feedback signal. Furthermore, we tap a charge amplifier specifically for needs to the phase of feedback signal. The experimental results indicate that the controller with our proposed charge amplifier can provide an effective solution to suppress the overall vibrations of a time-variant system even without phase compensation circuit.