| 摘要: | 電刺激 (Electrical Stimulation, ES) 在臨床治療與復健領域中具有廣泛應用，然而市面上的電刺激系統存在若干疑慮。主要包含因傳統波形模式與頻率選擇不佳等因素而導致輸出阻抗偏高、刺激期間造成使用者感到不適，以及因為電路架構耗能過高而產生裝置體積難以小型化等問題。此論文主要為針對功能性肌肉電刺激 (FES) 在刺激時誘發功能性抓握動作的特徵分析。肌肉電刺激的做動原理為透過低頻脈衝電流刺激失去神經控制的肌肉，透過電刺激引發病人肌肉強直性收縮（Tetanic Contraction），使病人萎縮或是受傷的肌肉可以強制收縮，達到治療與復健的效果。
為了解決上述的問題，本研究設計出一套可以輸出具有高頻調變的刺激波形且有多種參數可供切換的電刺激裝置。我們選用過去傳統的單相與雙相脈衝波、單相與雙相梯形波，並使用100KHz進行高頻調變。進而延伸出以下幾種刺激波形：單相與雙相脈衝波、單相與雙相梯形波、單相與雙相梯形波調變100KHz，以及不對稱雙相梯形波調變100KHz。可透過調整電流強度、刺激頻率、波形寬度大小來設置刺激規格，藉由不同的波形模式與刺激規格，能針對目標肌肉群進行更為適當的刺激。
實驗結果證實進行高頻調變後的波形可以有效解決上述所提及的問題，首先透過優化系統的電路架構，可以有效降低裝置整體的功率消耗，同時提高電流的使用效率。其次在輸出阻抗量測的實驗中，顯示具有高頻調變特性之波形所測得的數值相較於傳統無高頻調變特性之波形低。在受試者的疼痛指數調查表中也間接證明其有減緩在刺激期間所引起的刺痛感，有助於提高大眾對於電刺激治療的接受度。
透過肌電圖 (EMG) 與握力量測，以即時記錄不同刺激波形誘發肌肉收縮時的生理特徵反應。根據分析結果顯示，具備高頻調變特性的刺激波形在誘發肌肉收縮能力方面，呈現與無高頻調變波形相似的肌力收縮表現。然而，考量到肌電圖訊號於高頻調變條件下會參雜高頻成分，進而影響訊號解析與特徵提取的準確性，因此進一步設計出一套雙通道肌電訊號差分系統。由頻域分析可明確觀察到，該差分裝置能有效抑制高頻干擾，保留原始肌電訊號成分，為後續波形比較與特徵分析提供穩定且具參考價值的資料基礎。綜合上述成果，高頻調變技術的導入不僅能有效降低輸出阻抗，進而提升能量傳導效率與深層肌群刺激能力，同時改善使用者在刺激過程中的舒適度，並提升整體系統的電源使用效率與刺激穩定性。此研究在提高刺激品質、減少不適感與增進生理適應性方面展現出顯著潛力，為功能性電刺激裝置在臨床治療與復健介入中的優化提供了具體可行的技術依據。
;Electrical Stimulation (ES) has been widely applied in clinical therapy and rehabilitation. However, several concerns remain with commercially available stimulation systems. These include issues such as elevated output impedance due to suboptimal waveform patterns and frequency selection, discomfort experienced by users during stimulation, and excessive power consumption caused by inefficient circuit designs, which hinder the miniaturization of devices. This study focuses on the analysis of functional grasp movements induced by Functional Electrical Stimulation (FES), exploring the characteristics of muscle contractions and quantifying them through electromyographic (EMG) signals. FES operates by delivering low-frequency pulsed currents to stimulate muscles that have lost voluntary control, thereby inducing tetanic contractions, enabling atrophied or injured muscles to contract forcibly for therapeutic or rehabilitative purposes.
To address the aforementioned limitations, this research proposes a novel stimulation system capable of outputting high-frequency modulated waveforms with multiple adjustable parameters. Traditional monophasic and biphasic pulse and trapezoidal waveforms were selected as the base patterns, with 100 kHz carrier frequency modulation applied to develop the following waveforms: monophasic and biphasic pulses, monophasic and biphasic trapezoidal waves, 100 kHz-modulated versions of these trapezoidal waves, and asymmetric biphasic trapezoidal waves with 100 kHz modulation. By adjusting parameters such as current intensity, stimulation frequency, and pulse width, the system provides tailored stimulation for specific target muscles.
Experimental results demonstrated that high-frequency modulation effectively resolves the challenges. First, the optimized circuit design significantly reduces total power consumption and enhances current efficiency. Second, impedance measurements revealed that waveforms with high-frequency modulation exhibit lower output impedance than those without, supporting improved signal delivery. Pain index surveys further indicated that these waveforms reduce discomfort during stimulation, thereby increasing user acceptance of electrical therapy.
Real-time measurements of muscle responses were recorded using electromyography (EMG) and grip force sensors under various waveform conditions. Analytical results showed that high-frequency modulated waveforms produced muscle contraction strength comparable to conventional waveforms. However, due to high-frequency interference embedded in EMG signals under modulation, a dual-channel differential EMG acquisition system was developed. Frequency-domain analysis confirmed that this system effectively suppresses high-frequency noise while preserving volitional EMG components, providing reliable data for subsequent waveform comparison and feature extraction.
In summary, the introduction of high-frequency modulation not only reduces output impedance and improves energy transfer efficiency to deep muscle groups, but also enhances user comfort and overall system stability. The proposed method demonstrates significant potential in improving stimulation quality, reducing perceived discomfort, and enhancing physiological adaptability, offering a practical and effective technical foundation for optimizing FES systems in clinical and rehabilitative applications. |
