Load frequency modulation control system of piezoelectric ultrasonic transducer based on LADRC

Abstract

Ultrasonic processing technology is widely employed in various industrial applications, including welding, metal forming, and machining. In the practical operation of piezoelectric ultrasonic transducers, the piezoelectric ultrasonic transducers experience a resistance force from the workpiece, leading to a shift in resonance frequency. This shift significantly reduces the performance and service life of the piezoelectric ultrasonic transducers. To address this issue, this paper proposes a resonance frequency tracking algorithm for piezoelectric ultrasonic transducers, based on a Linear Active Disturbance Rejection Control (LADRC) system. The algorithm tracks the resonance frequency by controlling the impedance phase difference of the piezoelectric ultrasonic transducers, effectively reducing impedance phase difference to zero. This enables real-time tracking of frequency changes, enhances system robustness and anti-jamming capability, and improves the stability and reliability of the control system. Simulation and experimental results demonstrate that the LADRC method can rapidly and stably perform secondary frequency tracking with minor overshooting, even under conditions of no-load resonance, sudden force loads, and electric load fluctuations. These results highlight the method’s robustness and adaptability. The proposed approach ensures stable resonance frequency tracking of piezoelectric ultrasonic transducers under load conditions, offering significant practical value in real-world applications.