CN-121978900-A - Frequency tracking method, system, equipment and medium of ultrasonic therapeutic instrument

CN121978900ACN 121978900 ACN121978900 ACN 121978900ACN-121978900-A

Abstract

The invention discloses a frequency tracking method, a frequency tracking system, frequency tracking equipment and a frequency tracking medium of an ultrasonic therapeutic apparatus, and belongs to the technical field of ultrasonic therapeutic apparatus control. The method comprises the steps of monitoring the phase difference of a current signal and a voltage signal of a transducer, when the phase difference deviates from a preset threshold value, executing the following operation to determine the driving frequency of the transducer, determining an optimal solution through a particle swarm optimization algorithm, determining the driving increment of the driving frequency through a proportional integral derivative algorithm based on the optimal solution, and determining the driving frequency of the transducer based on the driving increment and the current driving frequency. The particle swarm optimization algorithm is used for determining the value of each parameter in the PID algorithm, so that the problem that the existing PID algorithm is difficult to realize the locking of the resonant frequency due to the fixed value of the parameter is solved.

Inventors

LIN JINCHAO
ZHU LONGLONG
PANG YU

Assignees

重庆邮电大学

Dates

Publication Date: 20260505
Application Date: 20260123

Claims (10)

1. A method of frequency tracking for an ultrasonic therapeutic apparatus, the method comprising: monitoring a phase difference of a current signal and a voltage signal of the transducer; performing the following operation to determine a driving frequency of the transducer when the phase difference deviates from a preset threshold; Determining an optimal solution through a particle swarm optimization algorithm; the particle swarm optimization algorithm updates inertia weight and learning factors based on a preset parameter updating rule in each iteration, and the optimal solution is characterized in that the optimal solution is used for determining the values of all parameters of a proportional-integral-derivative algorithm of the driving increment of the driving frequency; Determining a driving increment of the driving frequency by a proportional-integral-derivative algorithm based on the optimal solution; a drive frequency of the transducer is determined based on the drive increment and a current drive frequency.
2. The method according to claim 1, wherein the parameter updating rule specifically comprises: the value of the inertia weight linearly decreases with the increase of the iteration number; The learning factors include a first learning factor and a second learning factor, and the value of the first learning factor decreases linearly with increasing iteration number, and the value of the second learning factor increases linearly with increasing iteration number.
3. The method according to claim 1, wherein the objective function is in particular the root mean square of the measured phase errors within a predetermined time window; the phase error is a deviation of the phase difference from a desired phase.
4. The method of claim 1, wherein the drive delta is expressed as: the proportional coefficient, the integral coefficient and the differential coefficient of the proportional-integral-differential algorithm respectively carry out weighted sum on the first-order backward difference of the phase errors of three continuous sampling moments, the phase errors of the current sampling moment and the second-order backward difference of the phase errors; the phase error is a deviation of the phase difference from a desired phase.
5. The method of claim 1, wherein monitoring the phase difference of the current signal and the voltage signal of the transducer comprises: Respectively acquiring a current signal and a voltage signal of a transducer through a phase discriminator circuit; converting the current signal and the voltage signal into square wave signals respectively through a zero-crossing comparator of the phase discriminator circuit; based on the converted square wave signal, a phase difference of the current signal and the voltage signal is determined.
6. The method of claim 1, wherein the drive frequency is emitted by a drive circuit comprising an ultrasonic half-bridge drive circuit and a T-type impedance matching network, the drive circuit receiving square waves and PWM waves, respectively, and outputting a drive frequency that drives the transducer.
7. A frequency tracking system for an ultrasonic therapy apparatus, the system comprising: The monitoring module is used for monitoring the phase difference of the current signal and the voltage signal of the transducer; the main control module is used for executing the following operation to determine the driving frequency of the transducer when the phase difference deviates from a preset threshold value; Determining an optimal solution through a particle swarm optimization algorithm; the particle swarm optimization algorithm updates inertia weight and learning factors based on a preset parameter updating rule in each iteration, and the optimal solution is characterized in that the optimal solution is used for determining the values of all parameters of a proportional-integral-derivative algorithm of the driving increment of the driving frequency; Determining a driving increment of the driving frequency by a proportional-integral-derivative algorithm based on the optimal solution; a drive frequency of the transducer is determined based on the drive increment and a current drive frequency.
8. The system of claim 7, further comprising a drive circuit comprising an ultrasonic half-bridge drive circuit and a T-impedance matching network, wherein the drive circuit receives the square wave and PWM wave, respectively, and outputs a drive frequency that drives the transducer.
9. An electronic device comprising a processor, a memory and a program or instruction stored on the memory and executable on the processor, which program or instruction when executed by the processor implements the steps of the method of any of claims 1-6.
10. A storage medium having stored thereon a program or instructions which when executed by a processor perform the steps of the method according to any of claims 1-6.

Description

Frequency tracking method, system, equipment and medium of ultrasonic therapeutic instrument Technical Field The invention relates to the technical field of control of ultrasonic therapeutic apparatuses, in particular to a frequency tracking method, a system, equipment and a medium of an ultrasonic therapeutic apparatus. Background In the clinical application process of the portable ultrasonic therapeutic apparatus, the resonance frequency of the transducer is often shifted due to factors such as temperature rise, load change, tissue acoustic impedance difference and the like, and in order to avoid the problems of output power reduction, acoustic energy utilization rate reduction and the like caused by the shift of the resonance frequency, a frequency tracking technology is generally introduced to stabilize the resonance frequency. The conventional frequency tracking method mostly adopts a Proportional Integral Derivative (PID) algorithm with fixed parameters, and frequency adjustment is performed by detecting the phase difference between the voltage and the current of the transducer. Although the method has simple structure and convenient realization, the control parameters are fixed, the nonlinear characteristic and the environmental change of the system are difficult to adapt, the problems of low response speed, large steady state error, easy sinking into local optimum and the like are easy to occur, and the quick and stable resonant frequency locking is difficult to realize. The transducer is a core component for converting electric energy into ultrasonic waves in the ultrasonic therapeutic apparatus, and the electric characteristics of the transducer can be equivalent to an RLC (resistance inductance capacitance) equivalent circuit. In the RLC equivalent circuit, when the input frequency is equal to the natural resonant frequency of the transducer, the inductive reactance and the capacitive reactance cancel each other, the total impedance of the circuit is the resistance value of the equivalent resistance (presents "pure resistance"), the phase of the current and the voltage in the pure resistance circuit is completely synchronous, i.e. the phase difference is zero, at this time, the impedance in the circuit is minimum, and the electric energy input to the transducer can be converted into ultrasonic waves to the greatest extent, which is the ideal working state of the ultrasonic therapeutic apparatus. Therefore, in frequency tracking of the ultrasonic therapeutic apparatus, the phase difference between the voltage and the current is used as a basis. Disclosure of Invention The invention aims to provide a frequency tracking method, a system, equipment and a medium of an ultrasonic therapeutic apparatus, which determine the values of all parameters in a PID algorithm through a particle swarm optimization algorithm, and solve the problem that the existing PID algorithm is difficult to realize the locking of resonant frequency rapidly due to the fixed values of the parameters. The invention is realized by the following technical scheme: The first aspect of the present application provides a frequency tracking method of an ultrasonic therapeutic apparatus, the method comprising: monitoring a phase difference of a current signal and a voltage signal of the transducer; performing the following operation to determine a driving frequency of the transducer when the phase difference deviates from a preset threshold; Determining an optimal solution through a particle swarm optimization algorithm; the particle swarm optimization algorithm updates inertia weight and learning factors based on a preset parameter updating rule in each iteration, and the optimal solution is characterized in that the optimal solution is used for determining the values of all parameters of a proportional-integral-derivative algorithm of the driving increment of the driving frequency; Determining a driving increment of the driving frequency by a proportional-integral-derivative algorithm based on the optimal solution; a drive frequency of the transducer is determined based on the drive increment and a current drive frequency. In a possible implementation manner, the parameter updating rule specifically includes: the value of the inertia weight linearly decreases with the increase of the iteration number; The learning factors include a first learning factor and a second learning factor, and the value of the first learning factor decreases linearly with increasing iteration number, and the value of the second learning factor increases linearly with increasing iteration number. In a possible implementation, the objective function is specifically the root mean square of the measured phase error within a preset time window; the phase error is a deviation of the phase difference from a desired phase. In one possible implementation, the drive increment is expressed as: the proportional coefficient, the integral coefficient and the differential co