CN-121978899-A - Frequency tracking method of ultrasonic therapeutic apparatus based on fuzzy PID algorithm and related equipment

CN121978899ACN 121978899 ACN121978899 ACN 121978899ACN-121978899-A

Abstract

The invention discloses a frequency tracking method of an ultrasonic therapeutic apparatus based on a fuzzy PID algorithm and related equipment. The method comprises the steps of obtaining actual current of an ultrasonic transducer, determining current difference of the actual current relative to resonant current and change rate of the current difference when the actual current is smaller than the resonant current of the ultrasonic transducer, inputting the current difference and the change rate into a fuzzy algorithm to obtain adjustment amounts of all coefficients of a PID algorithm output by the fuzzy algorithm, determining values of all coefficients of the PID algorithm based on the adjustment amounts of all the coefficients of the PID algorithm, and determining driving frequency for driving the ultrasonic transducer based on the values of all the coefficients. The invention adjusts the PID parameters through fuzzy reasoning on the current difference and the change rate of the actual current and the resonant current, is suitable for nonlinear problems, and solves the problem of low frequency tracking precision caused by the fixed PID parameters.

Inventors

LIN JINCHAO
ZHU LONGLONG
PANG YU

Assignees

重庆邮电大学

Dates

Publication Date: 20260505
Application Date: 20260123

Claims (10)

1. The frequency tracking method of the ultrasonic therapeutic apparatus based on the fuzzy PID algorithm is characterized by comprising the following steps: acquiring actual current of an ultrasonic transducer; When the actual current is smaller than the resonant current of the ultrasonic transducer, determining a current difference of the actual current relative to the resonant current and a change rate of the current difference; inputting the current difference and the change rate into a fuzzy algorithm to obtain the adjustment quantity of each coefficient of a PID algorithm output by the fuzzy algorithm, wherein the fuzzy rule base of the fuzzy algorithm establishes the mapping relation between the adjustment quantity of each coefficient of the PID algorithm and the input quantity in each adjustment stage; determining the value of each coefficient of the PID algorithm based on the adjustment quantity of each coefficient of the PID algorithm; based on the values of the coefficients, a driving frequency at which the ultrasonic transducer is driven is determined.
2. The method according to claim 1, wherein the mapping relationship between the adjustment amount and the input amount of each coefficient of the PID algorithm in each adjustment stage is established in the fuzzy rule base of the fuzzy algorithm, and specifically includes: Determining a value rule of the value of each coefficient in each adjusting stage based on the physical meaning of each coefficient of the PID algorithm; and establishing a mapping relation between the adjustment quantity and the input quantity of each coefficient in each adjustment stage based on the characteristics of the current difference and the change rate in each adjustment stage and the value rule of the value of each coefficient in each adjustment stage.
3. The method of claim 2, wherein the coefficients include a proportional coefficient, an integral coefficient, and a derivative coefficient, the adjustment phase includes an early adjustment phase, a middle adjustment phase, and a late adjustment phase, and the value rule of the coefficients in each adjustment phase includes: the value of the proportionality coefficient in the initial adjusting stage is larger than that in the middle adjusting stage, and the value in the middle adjusting stage is larger than that in the later adjusting stage; the value of the integral coefficient at the initial stage of adjustment is smaller than that at the middle stage of adjustment, and the value at the middle stage of adjustment is smaller than that at the later stage of adjustment; the value of the differential coefficient in the early adjustment stage is larger than that in the middle adjustment stage, and the value in the middle adjustment stage is larger than that in the later adjustment stage.
4. The method of claim 1, wherein determining a driving frequency for driving the ultrasound transducer based on the values of the coefficients comprises: determining an increment value of the resonant frequency based on the value of each coefficient and the current difference of the last three samples; And determining the driving frequency of the adjusted driving ultrasonic transducer based on the increment value and the reference square wave.
5. A frequency tracking system of an ultrasonic therapeutic apparatus based on a fuzzy PID algorithm, the system comprising: the current acquisition unit is used for acquiring the actual current of the ultrasonic transducer; The current analysis unit is used for determining the current difference of the actual current relative to the resonance current and the change rate of the current difference when the actual current is smaller than the resonance current of the ultrasonic transducer; the system comprises a coefficient adjusting unit, a fuzzy algorithm and a fuzzy rule base, wherein the coefficient adjusting unit is used for inputting the current difference and the change rate into a fuzzy algorithm to obtain the adjustment quantity of each coefficient of a PID algorithm output by the fuzzy algorithm; a coefficient determination unit that determines the value of each coefficient of the PID algorithm based on the adjustment amount of each coefficient of the PID algorithm; And a driving frequency determining unit that determines a driving frequency at which the ultrasonic transducer is driven, based on the values of the coefficients.
6. An ultrasonic therapeutic apparatus, characterized in that the ultrasonic therapeutic apparatus comprises: the current acquisition circuit comprises a sampling resistor, and the actual current of the ultrasonic transducer is obtained by converting the voltage values at two ends of the sampling resistor into current values; The main control module is used for comparing the actual current with the resonant current of the ultrasonic transducer, and sending the current difference of the actual current relative to the resonant current and the change rate of the current difference to the frequency tracking algorithm module when the actual current is smaller than the resonant current of the ultrasonic transducer; And determining the value of each coefficient of the PID algorithm based on the adjustment amount of each coefficient of the PID algorithm, and determining the driving frequency for driving the ultrasonic transducer based on the value of each coefficient.
7. The ultrasonic therapeutic apparatus according to claim 6, further comprising an overheat protection module connected to the main control module, wherein the overheat protection module collects the temperature of the transducer through the thermistor and transmits the temperature to the main control module, and the main control module controls the operation state of the ultrasonic therapeutic apparatus based on the collected temperature value.
8. The ultrasonic therapy apparatus according to claim 6, further comprising a signal generator module and a drive module; The signal generator module is respectively connected with the main control module and the driving module; The signal generation module comprises a direct digital frequency synthesizer, and the direct digital frequency synthesizer generates square waves and sends the square waves to the driving module; The driving module generates driving frequency for driving the ultrasonic transducer based on the square wave and PWM wave generated by the main control module.
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 according to any of claims 1-4.
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 1-4.

Description

Frequency tracking method of ultrasonic therapeutic apparatus based on fuzzy PID algorithm and related equipment Technical Field The invention relates to the technical field of ultrasonic treatment equipment control, in particular to a frequency tracking method of an ultrasonic treatment instrument based on a fuzzy PID algorithm and related equipment. Background An ultrasonic therapeutic apparatus for treating diseases by using ultrasonic wave with frequency higher than 20kHz and physical actions such as mechanical vibration and thermal effect. Ultrasonic waves refer to mechanical waves with a frequency higher than 20kHz, and the physical characteristics of the ultrasonic waves enable the ultrasonic waves to have important application values in the biomedical field. The ultrasonic therapeutic apparatus converts electric energy into acoustic energy through an ultrasonic transducer (therapeutic head) to act on a human body so as to treat diseases. At present, most ultrasonic therapeutic apparatuses are driven by fixed frequency, but in actual operation, the resonant frequency of the transducer is shifted due to factors such as temperature change, load impedance fluctuation and the like, so that the energy conversion efficiency is reduced. The existing frequency tracking technology (such as a phase comparison method and an impedance analysis method) has the problems of slow dynamic response and high hardware complexity, and is difficult to meet the requirements of portable equipment on real-time performance and low power consumption. PID control is widely applied in dynamic systems, but traditional PID parameters are fixed, and accurate tracking is difficult to realize in nonlinear time-varying systems of ultrasonic therapy. Disclosure of Invention The invention aims to provide a frequency tracking method of an ultrasonic therapeutic apparatus based on a fuzzy PID algorithm and related equipment, which are suitable for nonlinear problems by adjusting PID parameters through fuzzy reasoning on the current difference and the change rate of actual current and resonant current, and solve the problem of low frequency tracking precision caused by fixed PID parameters. The invention is realized by the following technical scheme: the first aspect of the application provides a frequency tracking method of an ultrasonic therapeutic apparatus based on a fuzzy PID algorithm, which comprises the following steps: acquiring actual current of an ultrasonic transducer; When the actual current is smaller than the resonant current of the ultrasonic transducer, determining a current difference of the actual current relative to the resonant current and a change rate of the current difference; inputting the current difference and the change rate into a fuzzy algorithm to obtain the adjustment quantity of each coefficient of a PID algorithm output by the fuzzy algorithm, wherein the fuzzy rule base of the fuzzy algorithm establishes the mapping relation between the adjustment quantity of each coefficient of the PID algorithm and the input quantity in each adjustment stage; determining the value of each coefficient of the PID algorithm based on the adjustment quantity of each coefficient of the PID algorithm; based on the values of the coefficients, a driving frequency at which the ultrasonic transducer is driven is determined. In a possible implementation manner, a mapping relationship between an adjustment amount and an input amount of each coefficient of a PID algorithm in each adjustment stage is established in a fuzzy rule base of the fuzzy algorithm, and specifically includes: Determining a value rule of the value of each coefficient in each adjusting stage based on the physical meaning of each coefficient of the PID algorithm; and establishing a mapping relation between the adjustment quantity and the input quantity of each coefficient in each adjustment stage based on the characteristics of the current difference and the change rate in each adjustment stage and the value rule of the value of each coefficient in each adjustment stage. In one possible implementation manner, the coefficients comprise a proportional coefficient, an integral coefficient and a differential coefficient, the adjusting stage comprises an initial adjusting stage, a middle adjusting stage and a later adjusting stage, and the value rule of the coefficients in the adjusting stages comprises the following steps: the value of the proportionality coefficient in the initial adjusting stage is larger than that in the middle adjusting stage, and the value in the middle adjusting stage is larger than that in the later adjusting stage; the value of the integral coefficient at the initial stage of adjustment is smaller than that at the middle stage of adjustment, and the value at the middle stage of adjustment is smaller than that at the later stage of adjustment; the value of the differential coefficient in the early adjustment stage is larger than that in the mid