基于单片机的超声冲击装置频率跟踪控制和恒幅控制

对超声波冲击以提高焊接接头疲劳强度的装置进行了研究，研制出一台可用于实际冲击处理的样机。该样机以单片机为核心，采用自适应带通滤波器提取超声换能器工作的基波信号，在此基础上获得电流和电压的相位差，根据相位差用模糊控制方法来实现自动频率跟踪；通过电流控制执行机构的输出端振幅，使之恒定不变，对超声冲击处理的质量进行控制。该装置能够适应超声冲击这种负载变化十分剧烈的场合，并可实现准确的频率跟踪和保证冲击处理的质量及效率。

Single-chip microcomputer based frequency tracking and amplitude stabilizing for ultrasonic peening equipment

The equipment of ultrasonic peening for increasing fatigue strength of a welded joint is imposed and a corresponding ultrasonic peening prototype is manufactured. The prototype uses a single chip computer as control unit, an adaptive band-pass filter to obtain fundamental signal from ultrasonic transducer, and also a circuit is designed to measure the phase difference between the voltage and current. Fuzzy logic control is introduced to realize automatic frequency tracking according to the phase error, current control keep the output amplitude constant so as to control the quality of the ultrasonic peening. This equipment can adapt to the situation that the peening load varies strongly, and not only realize accurate frequency tracking, but also ensure the peening quality and efficiency.