本研究旨在開發一種具備全方向自適應能力之壓電式振動能量擷取系統（Omnidirectional Self-Adaptive Piezoelectric Energy Harvester, OSAPEH），並以梯形懸臂樑與偏心質量作為主要設計核心，探討其對系統運動行為、有效頻寬與輸出效能之影響。相較於傳統固定方向之壓電懸臂樑，本研究所提出之系統具有旋轉自由度，可在外部激振方向改變時，透過旋轉機構調整懸臂樑與激振方向之相對姿態，以提升多方向振動環境下之能量擷取能力。
在動力學建模方面，本研究以旋轉角度與懸臂樑末端位移作為主要廣義座標，並依據拉格朗日力學方法建立系統模型。模型中考慮懸臂樑等效剛性與等效質量、偏心質量所造成之轉動慣量與重力力矩、外部基座激振、旋轉機構摩擦阻尼以及壓電機電耦合效應，以描述系統於不同激振頻率與激振方向下之動態響應與電壓輸出特性。
實驗結果顯示，在相同體積條件下，梯形樑可將有效輸出頻率範圍由矩形樑之 1.65 Hz 提升至 2.05 Hz，最高方均根電壓由 0.52 V 提升至 0.56 V，最高輸出功率由 178.28 nW 提升至 210.64 nW，顯示梯形樑有助於拓寬系統有效頻寬並提升輸出能力。 加入偏心質量後，系統有效輸出頻率範圍維持於 2.05 Hz，但於自適應行為後之有效輸出區間中，最高方均根電壓由 0.34 V 提升至 0.39 V，最高輸出功率由 74.82 nW 提升至 101.40 nW，顯示偏心質量可強化系統於週期性擺動與單向旋轉區間之輸出表現。
模擬與實驗比較結果顯示，系統於不同激振頻率下可呈現自適應行為、週期性擺動與單向旋轉等運動模式，且修正後模型能合理描述上述動態行為。以梯形樑加偏心質量配置為例，實驗結果之有效輸出頻率範圍為 2.05 Hz，最高方均根電壓為 0.56 V，最高輸出功率為 210.64 nW；修正後模擬結果則分別為 2 Hz、0.57 V 與 214.15 nW。兩者於有效頻寬、峰值位置與整體輸出趨勢上具有良好一致性，顯示本研究所建立之模型具有一定可靠性。
綜合上述結果，本研究所提出之梯形樑與偏心質量整合設計，能有效提升 OSAPEH 於低頻、多方向振動環境下之有效頻寬與輸出表現。其中，梯形樑主要提升有效頻寬與基礎輸出能力，而偏心質量則可進一步增強高頻運動區間之能量轉換效果，因此可作為未來自供電感測系統、低功耗電子裝置與移動載具振動能量回收應用之設計參考。

This study develops an omnidirectional self-adaptive piezoelectric energy harvester (OSAPEH) for low-frequency and multidirectional vibration environments. The proposed device integrates a trapezoidal cantilever beam, a PVDF piezoelectric element, a rotational self-adaptive mechanism, and an eccentric mass to improve the directional limitation of conventional fixed-direction piezoelectric harvesters. A dynamic model was established using Lagrange’s method, considering beam equivalent properties, eccentric mass effects, bearing friction, base excitation, and piezoelectric electromechanical coupling.
A prototype was fabricated and tested under different excitation frequencies, excitation angles, structural configurations, and load resistances. Experimental results show that the trapezoidal beam increased the effective bandwidth from 1.65 Hz to 2.05 Hz, the maximum RMS voltage from 0.52 V to 0.56 V, and the maximum output power from 178.28 nW to 210.64 nW. The eccentric mass further enhanced the output response after self-adaptive motion, especially in periodic swing and unidirectional rotation regions. Corrected simulation results showed good agreement with experiments in effective bandwidth, peak response location, and overall output trend, confirming the feasibility of the proposed OSAPEH design.

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