- 學位論文
布拉格光纖光柵感測器應用於軌道承受撞擊以及移動載荷之動態量測以及抑振研究
The Dynamic Measurement Using Fiber Bragg Grating Sensor and Vibration Suppression Control of Rail System
摘要
本論文探討軌道系統之抑振控制，主要藉由鋼珠撞擊與滾動之實驗驗證正回授控制理論，同時透過懸臂梁系統探討撞擊與滾動對於系統頻域響應之影響。本文選用徑細質輕的短週期光纖光柵作為回授控制感測器，應用能量調變解調方法，搭配壓電片作為致動器抑制軌道系統之振動，並探討邊界條件的改變與垂直式光纖光柵感測器之安裝造成軌道系統共振頻飄移之現象。 軌道系統抑振控制實驗首先針對單一模態設計不同參數並加以抑振，再選擇控制各個模態之最佳參數，應用於軌道系統承受鋼珠單次、多次撞擊以及滾動激振之暫態運動的抑振控制。為了探討懸臂梁軌道系統的動態特性，並同時比較感測器不同架設方式對量測結果之差異，本論文選擇將布拉格光纖光柵採用垂直式與平貼式兩種黏貼方式，文章中採用的激振方式有鋼珠撞擊、壓電敲擊槌敲擊以及鋼珠低速與高速滾動，最後將鋼珠撞擊以及壓電敲擊槌實驗結果與有限元素法模擬結果做比較，而鋼珠滾動實驗則探討不同移動載荷速度對系統頻域響應之影響。 由軌道系統抑振控制實驗中，實現不同激振方式皆能有良好的抑振效果。從懸臂梁軌道系統實驗，得知面外架設方式對於彎曲模態以及扭轉模態有較佳的辨識度，而若是採用面內架設，則比面外架設更能清楚的量測到側向模態。此外，不同速度對懸臂梁系統低頻所造成的影響，以及滾動鋼珠‐懸臂梁系統內部共振的特性，都由實驗結果得到驗證。
並列摘要
This paper mainly investigates the dynamic characteristics and vibration control of the rail structure. Besides, this paper also explores the effect of cantilever beam frequency response by the excitation method of impact and roll. We choose fiber bragg grating (FBG) as a feedback control sensor and combine with PZT as the actuator to accomplish the vibration suppression control. By applying intensity-modulated FBG which has high sensitivity to dynamic measurement, we can deal with transient motion of system and even figure out the tiny change of frequency which is caused by boundary condition. First, we design different parameters and achieve vibration suppression for each modal individually and find out the best parameter of transient motion. Second, we apply these parameter to rail system under the various excitation of steel ball. In addition, we find out the effect of two different adhesive methods for FBG applied to the cantilever system and compare experimental results with simulation results in the steel ball impact and the piezoelectric percussion hammer experiment. On the other hand, we also discuss the influence of frequency response for system under different moving speed of the load. In conclusion , we carry out good vibration suppression result of rail system in different excitation ways , and we know there is a better recognition of bending mode and torsional mode by using vertical adhesive and that there is a better recognition of lateral mode by using inplane adhesive. Furthermore, we verify velocity is one of important impact factors in the low frequency of cantilever beam and there exists a internal resonance phenomenon of steel ball‐cantilever beam system .