超声振动切削中的自动调谐技术研究

在超声振动切削中,由于系统的发热及加工负载的变化,机械谐振系统的谐振频率会在较大范围内发生变化.若超声波电源的工作频率不能自动跟踪机械系统的谐振频率,超声振动切削就无法持续稳定地进行.为了解决上述问题,分析了超声振动切削系统的组成,剖析了系统中超声换能器的电阻抗特性,提出了根据换能器中电压和电流的相位差来调整超声波电源工作频率的自动调谐方法,并设计了相应的自动调谐系统.试验结果表明:该自动调谐方法在加工条件变化的情况下能使切削系统始终工作在谐振状态,实现连续稳定的振动切削.

Research on Automatic Resonating for Ultrasonic Vibration Cutting

In the process of ultrasonic vibration cutting (UVC), the resonant frequency of mechanical syntonic system varies in a wide range because of system's heating up and variable loads. If the ultrasonic power doesn't work at the resonant frequency of mechanical syntonic system, UVC is not able to go along continuously and stably. In order to solve the problem, the composition of an UVC system is introduced simply. Then, the electrical characteristics of ultrasonic magnetostrictive transducer are analysed. Finally, a method, with which to adjust the working frequency of the ultrasonic power in accordance with the phase shift frequency curve of ultrasonic magnetostrictive transducer, is presented. Experimental results indicate that this method can make UVC system work continuously and stably at situations of variable cutting conditions.