- 學位論文
磁流體式之無線被動可回復傾倒開關的研發
Development of Reversible, Wireless and Passive Tilt Recorder using Ferrofluid
摘要
物流過程中的存放方法直接影響貨物的品質，為了預防及減低運輸過程中損壞的風險，並發展出了傾倒監視器，可以很簡單地顯示出貨物有否曾經在運輸或倉存中被傾斜或橫放。無線量測功能可將感測器置於惡劣環境中監測或不適合接線的場合。被動式感測器可達節能效果。且為了提高產品的可靠性與可測試性， 並附加產品回復功能。 本論文研究重點在於研發一無線量測、被動式、可回復且加速度閾值小於1G之傾倒開關，其作動機制是當傾倒開關受到傾倒作用時，其液體式質量塊感測磁性流體會因為重力加速度方向改變而慣性移動，當感測磁性流體慣性移動的力量大於設計的匝道加速度閾值時，則開關開啟。為了使開關穩定開啟且具紀錄功能，則在開關開啟的區域做一深槽，使開關開啟後磁流體掉入深槽且不會受到反向加速度作用時而自動回復。透過LC電路的設計，由於液珠在不同區域時時電容間的介電常數改變，導致共振頻率也改變，並無線被動式的掃頻傾倒開關，便可知當下的開關狀態，達被動式量測功能。其中感測磁性流體可利用磁鐵的磁力將開關開啟後的磁流體回復至初始狀態，達被動式回復功能。 傾倒紀錄器之原型是由3D印表技術做出。實驗架構分為三部分進行可行性驗證，一為傾倒開關功能，起初將本傾倒開關做成全疏水結構，卻因此結構有許多盲點，如：磁流體會發生部分通過的現象，部分通過前後之加速度閾值不同，且部分通過共振頻率差異小(50 kHz)，難以判別開關狀態，於是將此結構改良成半疏水結構，半疏水結構不會發生部分通過的現象，且液珠大小為110 μL之傾倒開關重複使用加速度閾值皆能維持在0.9G以下，可靠度高，重現性佳，加速度閾值: 0.739 g - 0.849 g。二為回復功能，感測磁性流體本身的內聚力太差，對接觸面的疏水性不佳，需透過稀釋讓其更接近水的性質並還需兼顧可回復磁力，稀釋比值(MF: H2O)的比例是1 : 10 (9.09%)。三為被動式無線量測，傾倒開關重複使用對於共振頻率表現並無遞增或衰減的現象，可靠度高，重現性佳。傾倒前共振頻率估算值( for 110 μL ) : 151.964 kHz，因共振頻率之訊號強度差且被雜訊蓋過，故此值為估算值；傾倒後共振頻率測量值( for 110 μL ) : 10.05 MHz - 10.1 MHz。
並列摘要
Logistics process storage methods directly affect the quality of the goods. For avoid this condition that prevent and reduce the risk of damage during transport. Then tilt sensor has been developed. You can simply indicate the cargo whether the goods had been tilted during transportation or warehousing. Wireless sensor measurement functions can be placed in harsh environment monitoring or unsuitable wiring occasions. Passive sensors can reach energy savings. In order to promote product reliability and testability then additional products reversible function. This thesis focuses on Development of Reversible, wireless and Passive Tilt recorder. When the tilt recorder tilts. Its liquid-type proof mass sensing gravity acceleration's direction has been changed and inertia to move. When sensing magnetic fluid inertial mobile forces bigger than the design of the acceleration threshold, tilt recorder is open. In order to make the tilt recorder be open stability possessed record function. In the tilt recorder is open of the area to do a deep grooves. After the tilt recorder to open, the magnetic fluid fall into deep grooves and will not be reverse acceleration effect to reply by itself. Through the design of the LC circuit. Due to the liquid droplet in different areas would cause the dielectric constant been changed, and resonance frequency is changed, too. Then wireless passive sweep tilt recorder, would know the current switching state, reach wireless passive measurement functions. After the tilt recorder is open, use magnetic pulling sensing magnetic fluid back to initial chamber with the magnet, reach passive reversible function. The prototype of the tilt recorder is made by 3D printer technology. The results are divided into three parts. First, tilt recorder function. Initial the tilt recorder will be made to Full-hydrophobic design, but the structure has many blind spots. For example: The magnetic fluid will occur partial pass-through phenomenon, and acceleration threshold is different when partial pass-through be occurrence, and in the resonance frequency difference is small(50 kHz), hard to determine. Then improve Full-hydrophobic design into Half-hydrophobic design. Half-hydrophobic design would not occur partial pass-through phenomena, and the droplet size of 110 μL of tilt recorder reuse that acceleration threshold remained at 0.9G following, high reliability, good reproducibility. Acceleration threshold: 0.739 g - 0.849 g. Second, reversible function. Magnetic sensing fluid is bad to cohesion, and the contact surface of the hydrophobic poor. Need to be diluted by the water that near to nature of water and take into account magnetic to reply. Dilution ratio(MF: H2O): 1 : 10 (9.09%). In addition, wireless and passive measure. Tilt recorder that the resonant frequency reuse for performance is no increment or attenuation phenomenon, high reliability, good reproducibility. The resonance frequency before tilt for estimated(for 110 μL): 151.964 kHz, due to signal strength is poor and is overshadowed by the noise, therefore, it is a estimate value; The resonance frequency after tilt for real(for 110 μL): 10.05 MHz - 10.10 MHz.