獵能器為近二十年來新興的研究領域，其主要目的為利用各種能量轉換機制，將環境中的廢棄能量加以蒐集、儲存，以取代傳統電子產品之電池。本研究提出一種獵能器裝置，藉由並聯彈簧提供一位能場給予壓電懸臂樑末端滑塊，藉由手指按壓將滑塊推向位能不穩定點後釋放，滑塊帶動壓電樑被加速撞擊獵能器外殼後產生振動，再由壓電效應將機械能轉換成電能。前述撞擊持續時間很短，除了較低頻的第一模態之外，還會激發出高階模態。

本研究根據前述設計，製作獵能器原型量測其振動位移、暫態電壓響應以及獵取功率。實驗結果顯示，在單次按壓之下，獵能器產生之電功率可達10.01 mW，換算其功率密度為0.388 mW/cm3。本研究更透過橋式整流電路，將能量暫存在電容裡，並成功點亮LED燈。

為了更了解獵能器運作機制，本研究使用有限元素軟體ANSYS對獵能器動態行為做暫態分析，透過分析後發現，暫態電壓的高頻響應來自滑塊的瞬間之碰撞，最大電壓、滑塊速度以及第一模態頻率皆與壓電樑末端夾持長度及材料剛性有關，其他摩擦係數、阻尼設定等，也發現與數值運算的收斂性有關。

本論文藉由詳細的有限元素分析，疏理出暫態電壓響應產生之機制，在開迴路狀態下，有限元素所計算之電壓，與實驗量測有良好的一致性，顯示有限元素分析模型的正確性。由此研究奠定之基礎，為未來建立設計最佳化模型做準備，以更提昇獵能器之功率密度。

The piezoelectric energy harvesting technologies attract lots of attentions in recent two decades due to their potential to replace the batteries in electronic devices. In this study, a novel energy harvester is proposed. This device is composed of a piezoelectric beam with a slider block at its end and several springs. The springs provide a bi-stable potential field.
Based on the design concept, several prototypes were fabricated. The vibration displacements, transient voltage outputs and the power generation are measured in detail. The testing results showed that, the prototype can generate a power up to 10.01 mW, or a power density up to 0.388 mW/cm3, under a single press. A diode bridge was utilized to rectify the AC voltage and the electrical charges were stored in a capacitor. The stored energy was then released to light a LED.
In order to investigate the detail mechanism of the energy harvesting, the finite element method was used to compute the transient responses of the energy harvester. The analysis results indicated that the impact induces the higher vibration modes. The output voltage, velocity of slider and the frequency of the first mode depend on the beam length and stiffness of the materials. The convergence of the numerical calculation was found to depend on friction coefficient and damping.

[1]G. D. Pasquale, Sang-Gook Kim and D. D. Pasquale, "GoldFinger: wireless human–machine interface with dedicated software and biomechanical energy harvesting system," IEEE/ASME Transactions on Mechatronics, vol. 21, pp. 565-575, 2016.
[2]L. Xie, "An in-shoe harvester with motion magnification for scavenging energy from human foot strike," IEEE/ASME Transactions on Mechatronics, vol. 20, pp. 3264-3268, 2015.
[3]S. Roundy and P. K. Wright, "A piezoelectric vibration based generator for wireless electronics," Smart Materials and Structures, vol. 13, p. 1131, 2004.
[4]E. S. Leland and P. K. Wright, "Resonance tuning of piezoelectric vibration energy scavenging generators using compressive axial preload," Smart Materials and Structures, vol. 15, p. 1413, 2006.
[5]D. Zhu, M. J. Tudor, and S. P. Beeby, "Strategies for increasing the operating frequency range of vibration energy harvesters: a review," Measurement Science and Technology, vol. 21, p. 022001, 2010.
[6]H. Zhang and K. Afzalul, "Design and analysis of a connected broadband multi-piezoelectric-bimorph-beam energy harvester," IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, , vol. 61, pp. 1016-1023, 2014.
[7] HaoWu, Lihua Tang, Yaowen Yang and Chee Kiong Soh, "A novel two-degrees-of-freedom piezoelectric energy harvester," IEEE Intelligent Material Systems and Structures 2013 24: 357 originally published online 21 August 2012
[8]N. G. Elvin and A. A. Elvin, "Vibrational energy harvesting from human gait," IEEE/ASME Transactions on Mechatronics, vol. 18, pp. 637-644, 2013.
[9]L. Gu and C. Livermore, "Impact-driven, frequency up-converting coupled vibration energy harvesting device for low frequency operation," Smart Materials and Structures, vol. 20, p. 045004, 2011.
[10]M. Pozzi and M. Zhu, "Plucked piezoelectric bimorphs for knee-joint energy harvesting: modelling and experimental validation," Smart Materials and Structures, vol. 20, p. 055007, 2011.
[11]P. Pillatsch, E. Yeatman, and A. Holmes, "A scalable piezoelectric impulse-excited energy harvester for human body excitation," Smart Materials and Structures, vol. 21, p. 115018, 2012.
[12]T. Galchev, H. Kim, and K. Najafi, "Non-resonant bi-stable frequency-increased power scavenger from low-frequency ambient vibration," in Solid-State Sensors, Actuators and Microsystems Conference, 2009. TRANSDUCERS 2009. International, 2009, pp. 632-635.
[13]T. Galchev, H. Kim, and K. Najafi, "Micro power generator for harvesting low-frequency and nonperiodic vibrations," Journal of Microelectromechanical Systems, vol. 20, pp. 852-866, 2011.
[14]M. Pozzi, "Impulse excitation of piezoelectric bimorphs for energy harvesting: a dimensionless model," Smart Materials and Structures, vol. 23, p. 045044, 2014.
[15]X. Wu and D. W. Lee, "A seesaw-structured energy harvester with superwide bandwidth for TPMS application," IEEE/ASME Transactions on Mechatronics, vol. 19, pp. 1514-1522.
[16]A. Wickenheiser and E. Garcia, "Broadband vibration-based energy harvesting improvement through frequency up-conversion by magnetic excitation," Smart Materials and Structures, vol. 19, p. 065020, 2010.
[17]H. T. Luong and N. S. Goo, "Use of a magnetic force exciter to vibrate a piezocomposite generating element in a small-scale windmill," Smart Materials and Structures, vol. 21, p. 025017, 2012.
[18]K. Fan, J. Chang, F. Chao and W. Pedrycz, "Design and development of a multipurpose piezoelectric energy harvester," Energy Conversion and Management, vol. 96, pp. 430-439.
[19]P. Pillatsch, E. M. Yeatman, and A. Holmes, "A wearable piezoelectric rotational energy harvester," in 2013 IEEE International Conference on Body Sensor Networks (BSN), , 2013, pp. 1-6.
[20]P. Pillatsch, E. Yeatman, and A. Holmes, "Magnetic plucking of piezoelectric beams for frequency up-converting energy harvesters," Smart Materials and Structures, vol. 23, pp. 25009-25020, 2014.
[21]S. Wei, H. Hu, and S. He, "Modeling and experimental investigation of an impact-driven piezoelectric energy harvester from human motion," Smart Materials and Structures, vol. 22, p. 105020, 2013.
[22]ANSYS Mechanical APDL Theory Reference
[23]吳朗(1994)，電子陶瓷-壓電，全欣資訊圖書股份有限公司。
[24]efunda,PiezoSymbolDefinitions,http://www.efunda.com/Materials/piezo/piezo_math/symbol_definition.cfm
[25]ANSYS,Piezo And MENS
[26]Singiresu S. Rao, Mechanical Vibrations
[27]WIKEPEDIA,Bistability,https://en.wikipedia.org/wiki/Bistability
[28]WIKIPEDIA,Planestrain,https://en.wikipedia.org/wiki/Plane_stress
[29]寰辰科技股有限公司，壓電粉末特性表KA。