Design Of Resonance Frequency Selection System For A Sweeping Magnetostrictive Ultrasonic Transducer

With the discovery of giant magnetostrictive materials and the popularization of ultrasonic technology,the role of magnetostrictive ultrasonic transducer in the field of ultrasound is becoming more and more mature.Magnetostrictive ultrasonic transducer can realize electromechanical conversion of ultrasonic frequency band and its characteristic parameters play a decisive role in the overall performance of ultrasonic device.It is very important to determine the resonant frequency of the transducer in the application of ultrasonic system.When the frequency of the drive signal is equal to the natural frequency of the transducer’s mechanical system,the electroacoustic conversion efficiency is the highest.In practice,in order to increase the output energy of the device and reduce the loss of the system,it is sometimes necessary to use multiple transducer devices with the same or similar resonant frequencies to work at the same frequency at the same time.However,due to the different production process and structure size,the difference of resonant frequency points between different transducers of the same batch will inevitably be caused.Therefore,before the transducer equipment leaves the factory,it is very important to detect the resonant frequency directly,accurately and efficiently,which is of great significance for the better realization of the high-power output.This paper compares the two kinds of detection of magnetostrictive ultrasonic transducer resonant frequency method,including the current test and the maximum amplitude.Finally,a method was selected to determine the resonant frequency of the transducer by using the piezoelectric sensor to detect its maximum vibration amplitude.The influence of different waveforms and the adsorption position of piezoelectric sensors on the resonance frequency of magnetostrictive ultrasonic transducer was investigated,and a resonant frequency selection system of ARM-based sweeping magnetostrictive ultrasonic transducer is designed.The hardware circuit is designed,including the design of auxiliary power supply,power amplifier circuit and sampling circuit.At the same time,the generation of frequency sweep square wave signal,data acquisition and detection,LCD screen display and so on are realized through software programming.Finally,the system was assembled and the magnetostrictive ultrasonic transducer with different specifications was tested,the feasibility of the system was verified,the relevant problems in the design were summarized,and the modification suggestions were put forward.