摘要
本文提出一套輔以增強型不對稱諧振調變技術之壓電換能器驅動電路於超音波離合器應用開發。此研究動機在於超音波離合器常採大電流驅動而達成切離與接合功能，此法造成離合器快速接合致使轉軸承受極大旋轉扭力與輻射平面磨損問題，且無緩啟動機制以及存在電路與控制設計複雜問題。因此，本文研擬採用不對稱諧振驅動迴路，並彈性整合雙諧振槽與變壓器設計規劃，以節省諧振元件使用與建立不平衡驅動電壓供應壓電換能器。此外，此研究再提出一種增強諧振調變技術，其可同步調變換能器之操作電流振幅與頻率，裨益控制換能器位移振幅以利達成離合器調整與旋轉軸緩啟動，並改善離合器投入接合之摩擦問題。經模擬分析與硬體電路測試，實驗結果佐證此不對稱諧振調變技術確實兼具驅動壓電換能器振動與線性化位移等功能，成果頗助超音波離合器系統設計參考。
關鍵詞：壓電換能器、不對稱諧振、調變技術、超音波離合器Abstract
This paper proposes a piezoelectric transducers driving circuit with an enhanced asymmetric resonance modulation mechanism for ultrasonic clutch application. The motivation of the research lies in the engagement functions of ultrasonic clutch which often achieved by using high current in transducer driving. This method causes the rotary bearing subject extreme rotational torque and radiated plane friction during the fast clutch engagement. It also failed to provide the mechanism of soft start, and increased complexity of circuit and control design. Consequently, this research aims to adopt an asymmetric resonance driving loop with both additional flexible dual resonant tank and the transformers design procedure in order to save the use of resonance components and establish an unbalanced drive voltage supply for the transducer. In addition, the enhanced resonance modulation technique is also proposed in this study featuring the synchronous regulation of the current amplitude and its frequency in transducers. By means of the aforementioned technique, the adjustment and rotary soft start can be achieved by controlling the displacement amplitude of clutch while the plane friction can be improved. Through the simulation analysis and the hardware circuit testing, the experimental results have validated this good performance including transducer vibration and displacement linearity of the presented asymmetric resonance modulation mechanism. The researching achievements are deemed as beneficial references for the ultrasonic clutch system design.
Keywords: Piezoelectric Transducers, Asymmetric Resonance, Modulation Technique, Ultrasonic Clutch