基于性能可调阶梯型变幅杆的超声波振子调谐研究

为减小超声波振子外接负载时其谐振频率漂移的幅度，使用机电等效电路法和COMSOL Multiphysics 5.3有限元仿真软件设计制造了一种基于性能可调阶梯型变幅杆的超声波振子。对该超声波振子的谐振频率进行有限元仿真和现场测试。以超声清洗机为例，搭建与其原理相似的试验装置，以不同液面高度的水作为变幅杆的外接负载，探究在不同外接负载情况下，调节连接在变幅杆处压电晶堆的调谐电感对解决超声波振子谐振频率漂移问题的有效性。试验结果表明：随着水杯中液面高度的增加，超声波振子的谐振频率整体呈上升趋势；通过在变幅杆的压电晶堆处外接调谐电感，超声波振子的谐振频率会得到一定的补偿，可重新回归到原始设定的谐振频率值附近。研究表明在使用超声波振子进行超声辅助加工时，该超声波振子对减小外接负载引起的谐振频率漂移幅度具有一定作用。研究结果可为超声波振子的调谐提供新思路和新方法。

Research on tuning of ultrasonic oscillator based on performance-adjustable stepped horn

In order to reduce the amplitude of resonant frequency drift when the ultrasonic oscillator was connected to the external load, the electromechanical equivalent circuit method and COMSOL Multiphysics 5.3 finite element simulation software were used to fabricate an ultrasonic oscillator based on performance-adjustable stepped horn. Finite element simulation and field test of the resonant frequency of the ultrasonic oscillator were carried out. Taking the washing machine as an example, the test platform similar to its principle was built, and the water with different liquid level was used as the external load of the horn. The effectiveness of adjusting the tuning inductance of the piezoelectric stack connected to the horn to solve the problem of resonant frequency drift of ultrasonic oscillator under different loads was studied. The test results showed that the resonance frequency of the ultrasonic oscillator increased as the liquid height of the water cup increased. By externally connecting the tuning inductance at the piezoelectric crystal pile of the horn, the resonant frequency of the ultrasonic oscillator would be compensated and return to the original resonant frequency value. The research had shown that when using ultrasonic oscillator for ultrasonic assisted machining, the ultrasonic oscillator had a certain effect on reducing the amplitude of resonant frequency drift caused by external loads. The research results can provide a new idea and new method for the tuning of ultrasonic oscillator.