Research On Resonance Frequency Tracking Strategy For Ultrasonic Machining Process

Ultrasonic processing systems have been widely used in industrial production processes.Due to their unique processing methods,they have become an indispensable processing technology in the field of special materials processing.With the acceleration of industrialization,the need for ultrasonic processing systems Processing performance and efficiency have put forward higher requirements.For the ultrasonic machining system,automatic resonant frequency tracking and amplitude control under load conditions are two major technical problems it faces.This paper studies the electrical characteristics of piezoelectric transducers under load conditions,and proposes a strategy that can realize automatic resonant frequency tracking and amplitude control under load conditions.The following is the main research content:The Mason electromechanical equivalent model of the piezoelectric transducer uses the front cover radiated acoustic impedance to make the effect of the load force on the model equivalent,but the Mason electromechanical equivalent model does not clarify the impedance characteristics of the front cover radiated acoustic impedance.This article first discusses the impedance characteristics of the front cover radiated acoustic impedance,and brings the material parameters of the piezoelectric transducer into the Mason electromechanical equivalent model,and uses Matlab to calculate the radiated acoustic impedance of the front cover as a pure resistive load.Capacitive load and inductive load,the electrical characteristics of the piezoelectric transducer;then the electrical characteristics of the piezoelectric transducer under different load forces were tested,and it was found that only the current cover radiated acoustic impedance was a capacitive load At this time,the change rule of its electrical characteristics is consistent with the change rule of piezoelectric transducer under different load forces.Therefore,the assumption that the radiated acoustic impedance of the front cover in the Mason electromechanical equivalent model may be capacitive impedance is made.Based on this assumption,the effects of different capacitive loads on the electrical characteristic parameters(static capacitance,dynamic inductance,dynamic capacitance,and dynamic resistance)of the piezoelectric transducer are calculated,and it is found that the electrical characteristic parameters of the piezoelectric transducer are obvious Uncertainty.In-depth analysis of the electrical special diagnosis of piezoelectric transducers under different capacitive load sizes,summarizes 5 different piezoelectric transducer detuning situations,and proposes multi-band synchronous resonance for these 5 different detuning situations Frequency tracking strategy,and establish a Simulink simulation model based on multi-band synchronous resonant frequency tracking strategy.Five different detuning situations are simulated and analyzed one by one to verify the effectiveness of the tracking strategy.Regarding the amplitude control,this paper first tracks the resonance frequency,and then uses the PID algorithm for amplitude control.Simulations and experiments verify the effectiveness of the amplitude control scheme.Finally,this paper has performed performance tests on the proposed multi-band synchronous resonant frequency tracking strategy and amplitude control scheme.The multi-band synchronous resonant frequency tracking strategy and amplitude control scheme have been moved into the welding ultrasonic power supply program,and the actual test has been carried out under different external load conditions.The resonant frequency tracking effect and amplitude control situation of the welding ultrasonic power supply verify the effectiveness of the proposed multi-band synchronous resonant frequency tracking strategy and amplitude control scheme.