本研究旨在開發振動感測模組，利用實驗室開發之氮化鋁壓電製程製作微機電加速度計元件。研究主要聚焦於元件結構設計，改良加速度計典型結構，透過側質量設計、錐型樑設計及設計參數最佳化三個階段優化元件性能，並利用性能係數 (FOM) 綜合比較不同設計。在設計參數最佳化階段，本研究根據工具機應用設定相關規格限制，並以三軸靈敏度為目標函式進行求解，得出最佳設計參數組合。
將加速度計元件、電路板及金屬外殼組裝成振動感測模組後，使用雷射都卜勒測振儀 (LDV)、振動機系統 (Shaker system)、訊號分析儀 (Signal analyzer) 進行結構共振頻率、靈敏度、雜訊密度等性能測試，比較優化前後元件性能表現。首先量測元件結構共振頻率，測試結果顯示，優化前後結構的共振頻率分別為19 kHz和19.5 kHz。
隨後量測類比單軸振動感測模組各項性能。結果顯示，優化後元件的靈敏度為88.40 mV/g，比典型結構的54.78 mV/g增加了61%，雜訊密度為355 µg/√Hz，顯著低於典型設計的729 µg/√Hz，且兩者線性度均表現良好。
進一步將單軸模組延伸至三軸振動感測模組，測試結果顯示，優化後元件z軸靈敏度達55.01 mV/g，比典型結構的29.77 mV/g增加了84 %，雜訊密度分別為713 µg/√Hz和940 µg/√Hz；優化後元件x軸靈敏度為13.8220 mV/g，比典型結構的13.1984 mV/g增加了5 %，雜訊密度分別為2150 µg/√Hz和2683 µg/√Hz。而優化後的元件交叉軸靈敏度均小於典型設計，且三軸輸出訊號均呈高度線性。
本研究目的在於開發振動感測模組，並將其整合微控制器 (MCU)，以實現振動訊號的數位輸出。透過MCU內建的高精度ADC萃取三軸加速度計訊號，再透過UART介面與電腦進行通信。數位訊號將由本研究開發的使用者介面 (GUI) 顯示，該介面可實時 (Real-time) 顯示三軸振動訊號，並具備時域與頻域訊號分析功能，實現振動監測的目的。

This study aims to develop a vibration sensing module by utilizing in-house aluminum nitride piezoelectric process to fabricate MEMS accelerometer. This research focus on the accelerometer structure design, enhancing the typical structure of piezoelectric accelerometers through three stages: side mass design, tapered beam design, and design parameter optimization. The performance of different designs is compared using the figure of merit (FOM). During the design parameter optimization phase, we set relevant specifications based on machine tool applications as constraints and define three-axis sensitivity as the objective function to derive the optimal design parameter combination.
After assembling the accelerometer component, circuit board, and metal case into the vibration sensing module, performance tests were conducted using the LDV, shaker system, and signal analyzer. These tests measured structural resonance frequency, sensitivity, and noise density to compare the performance before and after optimization. The measurements of the structural resonance frequency showed that the resonance frequencies were 19 kHz and 19.5 kHz for the structures before and after optimization, respectively.
Subsequently, we tested the analog single-axis vibration sensing module. The results indicate that the sensitivity of the optimized component is 88.40 mV/g, representing an approximate 61% increase compared to the 54.78 mV/g of the typical structure. The noise density of the optimized structure is 355 µg/√Hz, significantly lower than the 729 µg/√Hz observed in the typical design. Both structures exhibit excellent linearity.
The study further extended the single-axis module to a three-axis vibration sensing module. Test results showed that the optimized component had a z-axis sensitivity of 55.01 mV/g, an 84% increase compared to the 29.77 mV/g of the typical structure, with noise densities of 713 µg/√Hz and 940 µg/√Hz, respectively. The x-axis sensitivity was 13.8220 mV/g, a 5% increase over the typical structure's 13.1984 mV/g, with noise densities of 2150 µg/√Hz and 2683 µg/√Hz, respectively. The cross axis sensitivity of optimized structure was lower than that of the typical design, and the three-axis output signals exhibited high linearity under different acceleration environments.
Additionally, this study realizes a three-axis vibration sensing module for digital output using a microcontroller (MCU). The high-precision ADC built into the MCU extracts three-axis accelerometer signals, which are communicated to a computer via a UART interface. The digital signals are displayed in real-time by a graphic user interface (GUI) developed in this study, featuring both time-domain and frequency-domain signal analysis capabilities, achieving the goal of vibration monitoring.

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