CN219293457U

CN219293457U - Ultrasonic polishing system

Info

Publication number: CN219293457U
Application number: CN202320165282.5U
Authority: CN
Inventors: 邱平; 刘恩明; 曾亚洲
Original assignee: Dongguan Jiayuanda Technology Co ltd
Current assignee: Dongguan Jiayuanda Technology Co ltd
Priority date: 2023-02-06
Filing date: 2023-02-06
Publication date: 2023-07-04
Anticipated expiration: 2033-02-06

Abstract

The utility model discloses an ultrasonic polishing system which is applied to a transducer, and comprises an input power supply, a microprocessor, a vibration feedback device, a feedback processing module and an inversion module; the microprocessor is connected with the inversion module and is configured to: generating PWM signals to drive the inversion module to work; outputting a reference signal; the inversion module is also respectively connected with the input power supply and the transducer; the vibration feedback device is connected with the feedback processing module and is configured to: generating a feedback signal based on when the transducer is in operation; the microprocessor is further coupled to the feedback processing module, the microprocessor further configured to: controlling a frequency of generating the PWM signal based on a phase difference of the feedback signal and the reference signal; the effect is that: realizing frequency tracking of the transducer; therefore, the digital substitution of frequency tracking is realized, and the influence caused by environmental changes such as temperature is greatly reduced.

Description

Ultrasonic polishing system

Technical Field

The utility model belongs to the technical field of ultrasonic waves, and particularly relates to an ultrasonic polishing system.

Background

In ultrasonic polishing application, because the patterns of the polishing head and the lock head which need to be carried are very many, the required frequency and vibration amplitude are different, and even the same polishing head can cause the need of different frequency driving when the loss degree is different, and the frequency difference is larger. For example, a 2mm thick fibro-oilstone is 27kHz in its intact state and can be raised to 29kHz for only half the length. The metal strip polishing head may only have 21kHz, and the conventional transducer is used to determine phase lock according to voltage and current phases, which may not work well due to the existence of multiple resonance working areas.

In the conventional technology, a single-chip phase-locked loop is used, and in a large-scale phase lock (such as an occasion requiring 10k bandwidth), the phase-locked loop is composed of an analog circuit, is greatly influenced by temperature, has a limited range capable of stably working, has the defect that a wide frequency tracking range cannot be realized, and often needs to be additionally provided with a tuning knob for adjusting a trackable frequency working area.

Disclosure of Invention

In order to at least partially solve the above-mentioned problems, the present utility model provides an ultrasonic polishing system, so as to solve the problem in the prior art that the tuning knob is required to be used due to the influence caused by environmental changes such as temperature, and the range of usable frequency bands is limited.

The technical scheme adopted by the utility model is as follows: an ultrasonic polishing system is applied to a transducer and comprises an input power supply, a microprocessor, a vibration feedback device, a feedback processing module and an inversion module; wherein the vibration feedback device is disposed on the transducer;

the microprocessor is connected with the inversion module and is configured to:

generating a PWM signal to drive the inversion module to work; and

outputting a reference signal by utilizing a high-precision timer built in the microprocessor;

the inversion module is also respectively connected with the input power supply and the transducer;

the vibration feedback device is connected with the feedback processing module and is configured to:

generating a feedback signal based on when the transducer is in operation;

the microprocessor is further coupled to the feedback processing module, the microprocessor further configured to:

based on the phase difference of the feedback signal and the reference signal, the frequency of the PWM signal is controlled to be generated so as to realize frequency tracking of the transducer.

Preferably, the inversion module comprises a driving circuit, and the driving circuit adopts any one of a full-bridge inversion circuit, a two-way half-bridge driving circuit and a one-way switch chopper circuit.

Preferably, the feedback processing module comprises a signal feedback processing circuit, wherein the signal feedback processing circuit comprises a current-limiting voltage-dividing circuit, a triode, an exclusive-OR gate chip and a filter circuit;

the feedback signal generated by the vibration feedback device is transmitted to the base electrode of the triode through the current-limiting voltage-dividing circuit, the emitter electrode of the triode is grounded, the collector electrode of the triode is connected with one input end of the exclusive-OR gate chip, the other input end of the exclusive-OR gate chip is connected with a pin of the microprocessor for outputting the reference signal, the output end of the exclusive-OR gate chip is connected with the input end of the filter circuit, and the output end of the filter circuit is connected with the microprocessor.

Preferably, the filter circuit adopts a second-order passive filter circuit.

Preferably, the vibration feedback device adopts a piezoelectric ceramic plate.

Preferably, the transducer comprises a lock head and a polishing head, and the polishing head is fixed on the lock head.

Preferably, the polishing head is a non-metallic or metallic part.

Preferably, the ultrasonic polishing system further comprises an impedance transformation module connected between the inversion module and the transducer, wherein the impedance transformation module adopts a mode of stringing in an inductor or integrating in an inductor.

By adopting the technical scheme, the method has the following advantages: according to the ultrasonic polishing system, the vibration feedback device is deployed on the transducer, and the feedback signal generated by the transducer during working is combined with the reference signal output by the transducer to obtain the phase difference, so that the frequency for generating the PWM signal is controlled to be changed, and the frequency tracking of the transducer is realized; therefore, the digital substitution of frequency tracking is realized, the influence caused by environmental changes such as temperature is greatly reduced, the usable frequency range is improved, and a tuning knob is not needed.

Drawings

Fig. 1 is a schematic structural diagram of an ultrasonic polishing system according to an embodiment of the present utility model;

fig. 2 is a schematic structural diagram of an ultrasonic polishing transducer according to an embodiment of the present utility model;

fig. 3 is a schematic circuit diagram of an inverter module according to an embodiment of the present utility model;

fig. 4 is a schematic circuit diagram of a signal feedback process according to an embodiment of the present utility model.

Detailed Description

To make the technical problems, technical solutions and advantages to be solved by the present utility model more apparent, the following detailed description will be made with reference to the accompanying drawings and specific embodiments, and the description herein does not mean that all subject matters corresponding to the specific examples set forth in the embodiments are cited in the claims.

Referring to fig. 1 to 4, an ultrasonic polishing system applied to a transducer includes an input power source, a microprocessor, a vibration feedback device, a feedback processing module and an inversion module; wherein the vibration feedback device is disposed on the transducer;

the microprocessor is connected with the inversion module and is configured to:

generating a PWM signal to drive the inversion module to work; and

the inversion module is also respectively connected with the input power supply and the transducer; and is configured to: converting the input direct current into an alternating current signal conforming to the use of the transducer;

generating a feedback signal based on when the transducer is in operation;

FIG. 2 is a schematic illustration of a structure of a grinding transducer, in which a "driving ceramic plate" is used to receive an ac driving signal generated by an inversion module, such as an ac frequency of 22kHz, the driving voltage is generally less than 100VACrms, the ceramic plate generates telescopic vibration under the excitation of the driving frequency, the vibration is transmitted to a lock head of a fixed grinding head through other structural members, the lock head is a replaceable component for adapting to fixing different grinding heads, and the grinding head is fixed on the lock head and can be a non-metal component such as fiber oilstone, wood strip, wood stick, etc., so that the grinding head vibrates under the driving of the lock head to realize a grinding effect; the sanding head may also be a metal part such as a file, rasp bar.

In fig. 2, the "feedback ceramic plate" is a vibration feedback device for measuring vibration intensity and phase value, and a piezoelectric ceramic plate is used. And two sides of the two feedback ceramic plates are respectively connected with a reference ground, and the output of a copper pole piece vibration feedback signal between the two ceramic plates is measured to be the instant sinusoidal vibration condition, which is the feedback signal.

In a specific implementation, the inversion module comprises a driving circuit, and the driving circuit adopts any one of a full-bridge inversion circuit, a two-way half-bridge driving circuit and a one-way switch chopper circuit.

In this embodiment, the microprocessor directly generates the phase-shifting full-bridge inverter PWM signal, and the used microprocessor needs to have a high-precision timer peripheral, which may be STM32F334, STM32G474 or STM32H750, STM32H7x3, etc. of the company of the Semiconductor (ST), or may also implement conventional operation, or may use a microprocessor with a high-precision PWM peripheral, such as TMS320F28035, etc. of the company of the semiconductor of the ideno (ADI), to generate the four-way full-bridge driving signal; the present application is preferably a full bridge inverter circuit.

In addition to the above implementation, impedance transformation is performed at the time of implementation; the ultrasonic polishing system further comprises an impedance transformation module connected between the inversion module and the transducer, wherein the impedance transformation module adopts a mode of series inductance or combination inductance.

Specifically, as shown in fig. 3, the inversion module inverts the dc voltage into an ac signal that meets the frequency requirement of the driving transducer. In fig. 3, the circuit of the inverter module includes:

the 4 paths of PWM signals from the microprocessor are input to the 2 nd and 3 rd pins of the MOS tube driving chip U18, the 2 nd and 3 rd pins of the U19 are respectively connected to the MOS tubes Q5 and Q6 through signals amplified by the U18 and U19, the Q5 and Q6 are internally composed of 2 NMOS, 4 MOS tubes are combined into a full-bridge inverter circuit, D24 and D25 are bootstrap diodes of the U18 and U19 respectively, C83 and C84 are bootstrap capacitors of the U18 and U19 respectively, R77, R78, R79 and R80 are G-pole resistors of the MOS tube, the effect of limiting driving current is achieved, and the full-bridge inverter circuit is selected according to the capability of the MOS driving chip; r84 is a current sampling resistor, the current flowing through the bridge arm passes through R84 to GND to form a loop, and according to the known quantity of i=u/R, U and R, the total current flowing through the inverter bridge arm can be obtained, and the current value can be used for power protection and other functions subsequently;

r81 and C85 form a first-order passive filter circuit, and play a role in filtering high-frequency interference. U20-2, R83, R85 form the in-phase amplifier, amplify the current signal value that R84 obtained in order to accord with the range of microprocessor analog-digital converter. R82 and C86 form a first-order passive filter circuit, and the filter is placed close to the MCU to reduce noise introduced in the wiring process. The signals output by R82 and C86 are connected into the peripheral of the analog-digital converter of the microprocessor, so that the microprocessor can read the real-time current value of the inverter bridge circuit. The current sampling signal can also be used for realizing nanosecond delay overcurrent protection without analog-digital converter sampling, and can be connected to a FAULT pin of a microprocessor, such as a FAULT pin of an HRTIM peripheral of STM32F 334.

Further, in operation, the feedback processing module comprises a signal feedback processing circuit, wherein the signal feedback processing circuit comprises a current-limiting voltage-dividing circuit, a triode, an exclusive-OR gate chip and a filter circuit;

Specifically, the sinusoidal alternating current signal generated by the feedback ceramic plate (i.e. the vibration feedback device) is input to the signal feedback processing circuit shown in fig. 4 through a wire, the input signal contains phase and amplitude information, and the feedback processing circuit processes the phase and amplitude information respectively;

the input signals are subjected to current limiting and voltage dividing to make the level conform to the voltage limiting process of driving the half-wave rectifying triodes Q7, D26 and D27, so that the input signals are input into the half-wave rectifying triodes Q7 and cannot exceed 3.3V+0.7V and cannot be lower than-0.7V, the Q7 triodes are about 0.55V and are conducted, the 2 feet of the conducting exclusive-OR gate chip U21 obtain low level, the high level pulled up by the R88 is achieved when the conducting exclusive-OR gate chip U21 is not conducted, the 1 feet of the exclusive-OR gate chip U21 are connected with a phase reference signal (namely the PWM signal of the MCU in fig. 4) from the MCU, the frequency of the signal is the same as the driving frequency, and the phase can be configured through a micro controller (namely a microprocessor) register.

The 4 pins of the exclusive or gate chip U21 will get the phase difference between the transducer feedback phase from pin 1 of U21 and the reference signal from the MCU. The phase difference signal is filtered into a direct current signal proportional to the phase difference by a second-order passive filter (namely the filter circuit) consisting of R86, C87, R87 and C88, and the direct current signal is transmitted to the microprocessor. R87 and C88 should be placed close to the microprocessor, and the subsequent microprocessor will track the operating frequency according to the phase difference value.

According to the technical scheme, the vibration feedback device is deployed on the transducer, and the feedback signal generated by the transducer during working is combined with the reference signal output by the transducer to obtain the phase difference, so that the frequency of the PWM signal is controlled to be changed, and frequency tracking of the transducer is realized; therefore, the digital substitution of frequency tracking is realized, the influence caused by environmental changes such as temperature is greatly reduced, the usable frequency range is improved, and a tuning knob is not needed.

It should be noted that this example also shows another processing of the vibration feedback signal; wherein R94 is the current limiting resistor of another circuit for amplitude measurement, the current limiting signal is subjected to half-wave rectification by D28 and then subjected to partial pressure adjustment by a potentiometer RP2, so that the output signal accords with the input range of an operational amplifier U22-1, C91, R94 and RP2 together form first-order active low-pass filtering, the filtering can filter the half-wave rectified signal into direct current, D29 is a voltage limiting protection diode, and the signal input to the 3 pin of the operational amplifier U22-1 is prevented from exceeding the allowable maximum value. The operational amplifier U22-1 is configured as a follower to prevent the signal output to the microcontroller from exceeding the supply voltage (3.3V in FIG. 4) of the U22-1, the operational amplifier U22 should be a rail-to-rail input-output operational amplifier which also serves to increase the driving capability to meet the input impedance requirements of the analog-to-digital converter peripherals of the microcontroller, R96, C92 form a first order active low pass filter circuit to further filter the vibration amplitude signal input to the microcontroller, and R96, C92 are also the front end RC element of the microcontroller analog-to-digital converter, R96 provides isolation between the operational amplifier U22-1 output and C92 to ensure stability of the operational amplifier U22-1, C92 serves as a charge bucket for the input charge kick of the microcontroller analog-to-digital converter to minimize voltage steps, thereby improving the sampling setup time. The vibration amplitude signal is sampled and quantized by the microcontroller and then used for controlling the output constant vibration amplitude of the transducer.

Here, it is to be noted that the functions, algorithms, methods, and the like, to which the present utility model relates, are merely conventional adaptive applications of the prior art. The present utility model is therefore an improvement over the prior art in that the connection between hardware is essentially not a function, algorithm, method itself, i.e. the present utility model, although it relates to a point of function, algorithm, method, does not include the improvement proposed by the function, algorithm, method itself. The description of the functions, algorithms and methods of the present utility model is presented in terms of a better understanding of the present utility model.

Finally, it should be noted that the above description is a preferred embodiment of the present utility model, and that a person skilled in the art, in light of the present disclosure, may make many similar representations without departing from the spirit and scope of the utility model as defined in the appended claims.

Claims

1. An ultrasonic polishing system is applied to a transducer and is characterized by comprising an input power supply, a microprocessor, a vibration feedback device, a feedback processing module and an inversion module; wherein the vibration feedback device is disposed on the transducer;

the microprocessor is connected with the inversion module and is configured to:

generating a PWM signal to drive the inversion module to work; and

generating a feedback signal based on when the transducer is in operation;

2. The ultrasonic polishing system of claim 1, wherein the inverter module comprises a drive circuit, and the drive circuit is any one of a full-bridge inverter circuit, a two-way half-bridge drive circuit, and a one-way switch chopper circuit.

3. The ultrasonic polishing system according to claim 1, wherein the feedback processing module comprises a signal feedback processing circuit comprising a current limiting voltage dividing circuit, a triode, an exclusive or gate chip and a filter circuit;

4. An ultrasonic polishing system according to claim 3 wherein the filter circuit employs a second order passive filter circuit.

5. An ultrasonic polishing system according to claim 4 wherein the vibration feedback device is a piezoelectric ceramic plate.

6. An ultrasonic polishing system according to claim 5 wherein the transducer comprises a locking head and a polishing head, the locking head having the polishing head secured thereto.

7. An ultrasonic polishing system according to claim 6 wherein the polishing head is a non-metallic or metallic component.

8. An ultrasonic polishing system according to any one of claims 3 to 7 further comprising an impedance transformation module connected between the inverter module and the transducer, the impedance transformation module being in the form of a series inductor or an integrated inductor.