Ultrasonic cleaning apparatus for metal workpiece ceramming and ultrasonic cleaning control method

Abstract

The present application relates to the technical field of ultrasonic cleaning of metal workpieces, and specifically relates to an ultrasonic cleaning device for ceramming of metal workpieces and an ultrasonic cleaning control method. The method acquires a target ultrasonic signal in a current time period in the ultrasonic cleaning process of a metal workpiece; acquires reference power spectrum data corresponding to each frequency according to the difference between the power spectrum data corresponding to each frequency in the target ultrasonic signal and the power spectrum data; acquires the surface complexity of the metal workpiece at the current time according to the size and confusion of the reference power spectrum data and the difference between each frequency and the main frequency, and further acquires the corrected rotating speed of the rotating handle at the current time to perform ultrasonic cleaning on the metal workpiece. The present application acquires the corrected rotating speed of the rotating handle at each time through real-time self-adaption, effectively improves the sufficiency and perfection of ultrasonic cleaning of metal workpieces, and is conducive to better ceramming of metal workpieces.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic cleaning of metal workpieces, in particular to an ultrasonic cleaning device for ceramization of metal workpieces and an ultrasonic cleaning control method. BACKGROUND

[0002] In the surface treatment process of metal workpieces, ceramization technology gradually replaces traditional phosphating process due to its environmental friendliness and high performance. The ceramization process forms a nanoscale ceramic conversion film on the metal surface, significantly improving the corrosion resistance, adhesion and environmental friendliness of the metal workpiece, and is widely used in the fields of automobiles, aerospace, electronics, etc. However, the ceramization process has very high cleaning requirements for metal substrates, and any residual dirt or oxide layer will affect the quality of the ceramization film. Therefore, as the core link of the pretreatment before ceramization, ultrasonic cleaning needs to ensure thorough cleaning of the surface of the metal workpiece.

[0003] In the existing method, a kind of ultrasonic cleaning equipment disclosed in patent publication No. CN217797762U is used to clean the metal workpiece before ceramization. The ultrasonic cleaning equipment includes a body, a cleaning tank is arranged in the body, a cleaning basket is arranged in the cleaning tank, a plurality of ultrasonic transducers are arranged on the cleaning tank, a cover plate is installed above the cleaning basket, a rotating rod is fixed to the left side of the cleaning basket, a gear is fixed to the left end of the rotating rod, and a handle is fixed to the gear. The working principle of the ultrasonic cleaning equipment is as follows: the ultrasonic transducer transmits high-frequency mechanical vibration to the liquid medium in the cleaning tank, generates cavitation effect, and removes the dirt on the surface of the metal workpiece through the high-pressure shock wave generated when the bubble collapses. At the same time, the rotating rod is driven to rotate the cleaning basket in the tank by rotating the handle at a fixed speed, so that the metal workpiece rotates in the cleaning tank to cover different cleaning areas of the metal workpiece at different angles.

[0004] However, in actual situations, the surface structure of metal workpieces is different, and the handle cannot adapt to different surface conditions of different metal workpieces and different surface conditions of different parts of the same metal workpiece when running at a fixed speed, which may result in insufficient cleaning or excessive cleaning of some areas of the metal workpiece, leading to insufficient cleaning or excessive cleaning of the surface of the metal workpiece. SUMMARY

[0005] To solve the technical problem of insufficient cleaning or excessive cleaning of some areas of the metal workpiece caused by the handle running at a fixed speed, the purpose of the present application is to provide an ultrasonic cleaning device for ceramization of metal workpieces and an ultrasonic cleaning control method, and the technical solution adopted is as follows:

[0006] In a first aspect, an embodiment of the present application provides an ultrasonic cleaning control method for ceramization of metal workpieces, which includes the following steps:

[0007] acquire a target ultrasonic signal in a current time period in an ultrasonic cleaning process of a metal workpiece; wherein the target ultrasonic signal comprises a straight-through ultrasonic signal and a reflected ultrasonic signal;

[0008] acquire reference power spectrum data corresponding to each frequency in the reflected ultrasonic signal in the current time period according to a difference between power spectrum data corresponding to each frequency in the target ultrasonic signal and the characteristic power spectrum data; wherein the characteristic power spectrum data is power spectrum data acquired through the straight-through ultrasonic signal;

[0009] acquire a surface complexity of the metal workpiece at the current time according to a size and a chaotic situation of the reference power spectrum data and a difference between each frequency in the reflected ultrasonic signal in the current time period and a main frequency; wherein the main frequency is an operating frequency of an ultrasonic transducer;

[0010] adjust a rotating speed of a rotating handle at the current time based on the surface complexity to acquire a corrected rotating speed of the rotating handle at the current time and perform ultrasonic cleaning on the metal workpiece.

[0011] Further, the method for acquiring the characteristic power spectrum data comprises:

[0012] acquire ultrasonic signals in a specified time period of the metal workpiece as reference ultrasonic signals, divide the reference ultrasonic signals through a time window of a preset length, perform windowing processing on the reference ultrasonic signals in each time window through a Hanning window, and then acquire first power spectrum data in each time window through short-time Fourier transform;

[0013] take an average of the first power spectrum data in all time windows corresponding to the reference ultrasonic signals as the characteristic power spectrum data.

[0014] Further, the method for acquiring the reference power spectrum data comprises:

[0015] for any frequency in the target ultrasonic signal, acquire a difference between power spectrum data corresponding to the frequency in the target ultrasonic signal and the characteristic power spectrum data as reference power spectrum data corresponding to the frequency in the reflected ultrasonic signal in the current time period; wherein when the reference power spectrum data is negative, the reference power spectrum data is set to 0.

[0016] Further, the method for acquiring the surface complexity comprises:

[0017] acquire a total energy of the reflected ultrasonic signal in the current time period according to a size of the reference power spectrum data corresponding to each frequency in the reflected ultrasonic signal in the current time period;

[0018] According to the difference between each frequency in the echo ultrasonic signal in the current time period and the main frequency, and the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period, the main energy concentration degree of the echo ultrasonic signal in the current time period is obtained.

[0019] According to the confusion degree of the reference power spectrum data corresponding to all frequencies in the echo ultrasonic signal in the current time period, the instability degree of the echo ultrasonic signal in the current time period is obtained.

[0020] According to the total energy, the main energy concentration degree and the instability degree, the surface complexity degree of the metal workpiece at the current moment is obtained; wherein, the total energy and the instability degree are positively correlated with the surface complexity degree, and the main energy concentration degree is negatively correlated with the surface complexity degree.

[0021] Further, the total energy obtaining method is:

[0022] The result of adding all the reference power spectrum data and then normalizing is taken as the total energy of the echo ultrasonic signal in the current time period.

[0023] Further, the main energy concentration degree obtaining method is:

[0024] For any frequency in the echo ultrasonic signal in the current time period, the result of negatively correlating and normalizing the difference between the frequency and the main frequency is taken as the participation weight of the frequency;

[0025] The product of the participation weight of the frequency and the reference power spectrum data corresponding to the frequency is taken as the main energy participation value corresponding to the frequency;

[0026] The result of adding the main energy participation values corresponding to all frequencies in the echo ultrasonic signal in the current time period and then normalizing is taken as the main energy concentration degree of the echo ultrasonic signal in the current time period.

[0027] Further, the instability degree obtaining method is:

[0028] The reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period is uniformly normalized, and the signal entropy corresponding to the normalized reference power spectrum data is taken as the instability degree of the echo ultrasonic signal in the current time period.

[0029] Further, the corrected rotating speed obtaining method is:

[0030] The product of the preset initial rotating speed of the handle and the surface complexity degree is taken as the rotating speed adjustment value of the handle at the current moment;

[0031] The difference between the preset initial rotating speed and the rotating speed adjustment value is taken as the corrected rotating speed of the handle at the current moment.

[0032] Further, the through-transmission ultrasound signal is an ultrasound signal directly emitted by the ultrasonic transducer;

[0033] The echo ultrasound signal is an ultrasound signal corresponding to the reflection of the ultrasonic transducer emitted ultrasound wave after the reflection of the metal workpiece.

[0034] In a second aspect, another embodiment of the present application provides an ultrasonic cleaning device for metal workpiece tempering, comprising an ultrasonic cleaning mechanism for metal workpiece tempering, the ultrasonic cleaning mechanism for metal workpiece tempering comprising an ultrasonic probe embedded in the bottom of the cleaning tank, a motor control module installed at the handle portion, the ultrasonic probe being used to acquire the ultrasonic signal in the cleaning tank in real time, the motor control module being used to control the rotating speed of the handle, the output end of the ultrasonic probe being connected with the input end of the motor control module, and the ultrasonic cleaning device for metal workpiece tempering can realize the steps of any one of the above methods.

[0035] The present application has the following beneficial effects:

[0036] The ultrasonic probe embedded in the bottom of the cleaning tank acquires the target ultrasonic signal in the current time period during the ultrasonic cleaning of the metal workpiece and transmits it to the motor control module, the motor control module acquires the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period according to the difference between the power spectrum data corresponding to each frequency in the target ultrasonic signal and the characteristic power spectrum data, accurately reflects the energy corresponding to each frequency in the echo ultrasonic signal in the current time period, and is beneficial to the subsequent accurate analysis of the complex situation of the metal workpiece surface at the current time; then, according to the size and confusion of the reference power spectrum data and the difference between each frequency and the main frequency in the echo ultrasonic signal in the current time period, the surface complexity of the metal workpiece at the current time is acquired, the complex situation of the metal workpiece surface close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current time is accurately reflected, which is beneficial to the accurate adjustment of the rotating speed of the handle at the current time, and ensures that the metal workpiece surface close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current time is fully cleaned while avoiding excessive cleaning to cause resource waste; therefore, the rotating speed of the handle at the current time is adjusted based on the surface complexity, the corrected rotating speed of the handle at the current time is acquired to perform ultrasonic cleaning on the metal workpiece, the sufficiency and perfection of the ultrasonic cleaning of the metal workpiece are effectively improved, and the metal workpiece is beneficial to better tempering treatment. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, the following will briefly introduce the drawings required by the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic flow chart of an ultrasonic cleaning control method for metal workpiece ceramming provided by an embodiment of the present application;

[0039] Figure 2 A flow chart of a surface complexity acquisition method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0040] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, the following will combine the drawings and the preferred embodiments to specifically describe the ultrasonic cleaning equipment and the ultrasonic cleaning control method for metal workpiece ceramming according to the present application, the specific implementation, structure, features and effects thereof in detail. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0042] The following will specifically describe the specific schemes of the ultrasonic cleaning equipment and the ultrasonic cleaning control method for metal workpiece ceramming provided by the present application in combination with the drawings.

[0043] The application provides an ultrasonic cleaning device for metal workpiece ceramming, which comprises an ultrasonic cleaning mechanism for metal workpiece ceramming, which is improved on the basis of the ultrasonic cleaning device disclosed in patent publication No. CN217797762U. The ultrasonic cleaning mechanism for metal workpiece ceramming adds an ultrasonic probe and a motor control module to the disclosed ultrasonic cleaning device. The ultrasonic probe is embedded in the bottom of the cleaning tank and is used to obtain ultrasonic signals in the cleaning tank in real time. The motor control module is installed at the handle part and is used to control the speed of the handle. The position of the motor control module can be set according to the actual situation, but it must be ensured that the motor control module is connected with the handle speed control module, and the motor control module can control the speed of the handle. The control of the motor control module on the handle speed depends on the ultrasonic signals obtained by the ultrasonic probe in real time. Therefore, the output end of the ultrasonic probe is connected with the input end of the motor control module. It should be noted that wired connection can be achieved through data transmission lines during data transmission and control, or wireless connection can be achieved through Bluetooth, WiFi and other wireless communication methods. This is not limited.

[0044] The working process of the ultrasonic cleaning mechanism for metal workpiece ceramming is as follows: the operator can place the metal workpiece to be cleaned at the bottom of the cleaning basket, then place the partition plate between the two groups of positioning blocks, clamp the partition plate by the elastic force of the two springs, then place another metal workpiece of the same kind on the partition plate, cover the cover plate, place the T-shaped rod into the cleaning basket through the through hole on the cover plate, make the T-shaped rod fit with the partition plate by rotating the second bolt, then pour cleaning liquid into the cleaning tank, finally tighten the first bolt on the fixed plate to fix the cover plate on the cleaning basket, start the ultrasonic transducer and the ultrasonic generator to clean the workpiece in the cleaning tank, and rotate the handle at the initial set speed to drive the rotating rod to rotate, so that the cleaning basket rotates and overturns, so that the metal workpiece is more fully cleaned. Considering that the surface structure of the metal workpiece may be different, in order to ensure sufficient cleaning of the metal workpiece and avoid excessive cleaning and waste of resources, the ultrasonic signals obtained by the ultrasonic probe in real time are transmitted to the motor control module, the motor control module synchronously analyzes the input ultrasonic signals, determines the surface structure of the metal workpiece corresponding to the surface of the cleaning basket closest to and facing the ultrasonic transducer in real time, and adjusts the speed of the handle in real time to ensure that the surface of the metal workpiece is fully cleaned while avoiding excessive cleaning. When the handle stops rotating, the positioning rod can clamp the ratchet pawl on the gear to position the cleaning basket. After cleaning, the ultrasonic transducer and the ultrasonic generator are turned off, the cleaning basket is turned to the cover plate facing upward, the T-shaped rod is removed, the cover plate is opened, and then the upper metal workpiece is taken out. The lower metal workpiece can be taken out after the partition plate is removed.

[0045] In order to clarify the adjustment process of the motor control module to the rotating handle speed, the application also provides an ultrasonic cleaning control method for metal workpiece ceramming, including the specific implementation steps of the motor control module, please refer to Figure 1 which shows a schematic flow chart of an ultrasonic cleaning control method for metal workpiece ceramming provided by an embodiment of the application, the method includes the following steps:

[0046] Step S1: obtaining the target ultrasonic signal in the current time period during the metal workpiece ultrasonic cleaning process; wherein the target ultrasonic signal includes the straight-through ultrasonic signal and the echo ultrasonic signal.

[0047] Specifically, it is known that the ultrasonic transducer is installed at the bottom of the cleaning tank, and the cavitation effect of the metal workpiece surface near the bottom of the cleaning tank and facing the ultrasonic transducer is the strongest, which can quickly strip the stubborn dirt on the corresponding metal workpiece surface. Therefore, after the metal workpiece is fixed in the cleaning basket, the cleaning basket is rotated by rotating the rotating handle to adjust the position of the surface of each part of the metal workpiece relative to the ultrasonic transducer, so that the metal workpiece surface is completely cleaned. Considering that the shape of the metal workpiece is irregular, in order to fully clean the surface of the metal workpiece, it is necessary to analyze the metal workpiece surface near the bottom of the cleaning tank and facing the ultrasonic transducer in real time, so as to adjust the rotating speed of the rotating handle in real time, and ensure that the metal workpiece surface is fully cleaned.

[0048] It is known that during the metal workpiece ultrasonic cleaning process, the ultrasonic waves emitted by the ultrasonic transducer will propagate in the liquid, and will be reflected, scattered or refracted when encountering the metal workpiece surface, forming echo ultrasonic signals which are collected by the ultrasonic probe. At the same time, the ultrasonic waves emitted by the ultrasonic transducer can be directly transmitted to the ultrasonic probe through the cleaning tank bottom plate, because the ultrasonic transducer and the ultrasonic probe are both installed on the cleaning tank bottom plate, and the ultrasonic probe simultaneously collects the straight-through ultrasonic signal corresponding to the ultrasonic waves directly emitted by the ultrasonic transducer. Therefore, the ultrasonic signal collected by the ultrasonic probe contains the straight-through ultrasonic signal and the echo ultrasonic signal. Among them, the information carried by the echo ultrasonic signal can indirectly show the structure of the metal workpiece surface near the bottom of the cleaning tank and facing the ultrasonic transducer, and in order to analyze the complexity of the metal workpiece surface near the bottom of the cleaning tank and facing the ultrasonic transducer in real time, the rotating speed of the rotating handle is controlled in real time during the metal workpiece ultrasonic cleaning process, and the ultrasonic signal during the metal workpiece ultrasonic cleaning process is obtained by the ultrasonic probe in real time.

[0049] In view of the fact that in actual situations there may be high-frequency cavitation noise and low-frequency mechanical vibration interfering with the ultrasonic signal, therefore, the embodiment uses a band-pass filter to filter the ultrasonic signal directly obtained by the ultrasonic probe, it should be noted that the working frequency of the ultrasonic transducer is known, and due to scattering and attenuation, the echo ultrasonic signal may appear frequency shift or spectral broadening, therefore, the embodiment is based on the working frequency of the ultrasonic transducer to widen ±5 kHz, as the passband range of the band-pass filter, while removing the interference signal, effectively preserving the integrity of the echo ultrasonic signal. The implementer can set the passband range of the band-pass filter according to the actual situation, which is not limited here. It should be noted that the subsequent ultrasonic signal is the ultrasonic signal filtered by the band-pass filter.

[0050] In order to obtain the reasonable rotating speed of the rotating basket at the current time, so that the metal workpiece surface is fully cleaned at the current time while avoiding excessive cleaning causing resource waste, and considering that the rotation of the cleaning basket must be slow, the embodiment obtains the ultrasonic signal in the current time period in the ultrasonic cleaning process of the metal workpiece as the target ultrasonic signal, wherein the target ultrasonic signal includes the straight-through ultrasonic signal and the echo ultrasonic signal. The embodiment sets the duration of the current time period to 0.3 seconds, and the implementer can set the duration of the current time period according to the actual situation, which is not limited here, it should be noted that the end time of the current time period is the current time.

[0051] Step S2: According to the power spectrum data corresponding to each frequency in the target ultrasonic signal and the difference between the power spectrum data, obtain the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period; wherein the power spectrum data is the power spectrum data obtained by the straight-through ultrasonic signal without the influence of the metal workpiece.

[0052] Specifically, since the frequencies of the straight-through ultrasonic signal and the echo ultrasonic signal are similar, the existing filter cannot separate the straight-through ultrasonic signal and the echo ultrasonic signal contained in the target ultrasonic signal. Considering that the target ultrasonic signal is essentially a superimposed signal of the straight-through ultrasonic signal and the echo ultrasonic signal in the current time period, the straight-through ultrasonic signal is synchronous with the ultrasonic transducer driving signal, and the straight-through ultrasonic signal is the ultrasonic signal corresponding to the ultrasonic wave directly emitted by the ultrasonic transducer, therefore, the ultrasonic signal obtained by turning on the ultrasonic transducer in the absence of a metal workpiece is the straight-through ultrasonic signal. It should be noted that the frequency of the ultrasonic transducer and the temperature of the cleaning liquid in the cleaning tank are always consistent in this embodiment. The amplitude of the straight-through ultrasonic signal is large and stable, and the echo ultrasonic signal will fluctuate to varying degrees due to the influence of the surface of the metal workpiece, therefore, the embodiment can obtain the frequency domain signal of the echo ultrasonic signal by the difference between the frequency domain performance of the target ultrasonic signal and the fixed performance of the straight-through ultrasonic signal, which is beneficial to accurately analyze the complex situation of the surface of the metal workpiece close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current time. Therefore, according to the difference between the power spectrum data corresponding to each frequency in the target ultrasonic signal and the characteristic power spectrum data, the embodiment obtains the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period; wherein the characteristic power spectrum data is the power spectrum data obtained by the straight-through ultrasonic signal. The method for obtaining the power spectrum data corresponding to each frequency is known and will not be described in detail.

[0053] The method for obtaining the characteristic power spectrum data is: obtaining the ultrasonic signal of the metal workpiece in the specified time period as the reference ultrasonic signal by the ultrasonic probe, it should be noted that the working state of the ultrasonic transducer in the process of obtaining the reference ultrasonic signal is exactly the same as that in the current time period, and the temperature of the cleaning liquid in the cleaning tank is also the same. The embodiment sets the length of the specified time period to 15 seconds, and the implementer can set the size of the specified time period according to the actual situation, which is not limited herein. The reference ultrasonic signal is divided by a time window with a preset length, then the reference ultrasonic signal in each time window is windowed by a Hanning window, and then the first power spectrum data in each time window is obtained by short-time Fourier transform; the embodiment sets the preset length to 50 milliseconds, and the implementer can set the size of the preset length according to the actual situation, which is not limited herein. Since the frequency of the straight-through ultrasonic signal is the same as the working frequency of the ultrasonic transducer, the embodiment defaults that the first power spectrum data are all corresponding to the working frequency, and then the mean value of the first power spectrum data in all time windows is taken as the characteristic power spectrum data, that is, the power spectrum data fixed corresponding to the straight-through ultrasonic signal. The Hanning window and the short-time Fourier transform are both known technologies and will not be described in detail.

[0054] Preferably, in one possible implementation of this embodiment, the reference power spectrum data is obtained by obtaining, for any frequency in the target ultrasonic signal, the difference between the power spectrum data corresponding to that frequency in the target ultrasonic signal and the representative power spectrum data, and using this difference as the reference power spectrum data corresponding to that frequency in the echo ultrasonic signal during the current time period. When the reference power spectrum data is negative, the reference power spectrum data is set to 0 because the target ultrasonic signal includes a through ultrasonic signal, and the reference power spectrum data must be greater than or equal to 0.

[0055] At this point, obtaining the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period is conducive to the subsequent accurate analysis of the complex situation of the metal workpiece surface near the bottom of the cleaning tank and facing the ultrasonic transducer at the current moment.

[0056] Step S3: Obtain the surface complexity of the metal workpiece at the current moment based on the size and disorder of the reference power spectrum data and the difference between each frequency and the main frequency in the echo ultrasonic signal in the current time period; wherein the main frequency is the operating frequency of the ultrasonic transducer.

[0057] Specifically, the echo ultrasonic signal is mainly formed by the reflection of the ultrasonic wave on the surface of the metal workpiece during the propagation of the ultrasonic wave in the liquid. When the surface of the metal workpiece close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current moment is larger, more sound wave energy will be reflected back to the ultrasonic probe in the current time period. The stronger the energy of the echo ultrasonic signal, the larger the reference power spectrum data. Furthermore, this embodiment can preliminarily analyze the surface complexity of the metal workpiece at the current moment by the size of the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period.

[0058] It is known that the rougher the surface of a metal workpiece, the stronger the ultrasonic scattering and the more dispersed the reflected ultrasonic energy. Therefore, the rougher the surface of the metal workpiece near the bottom of the cleaning tank and facing the ultrasonic transducer at the current moment, the less concentrated the energy corresponding to the reference power spectrum data in the current time period. Under normal circumstances, the main frequency of the echo ultrasonic signal and the main frequency of the direct ultrasonic signal are consistent by default. Therefore, the main frequency of the echo ultrasonic signal is the operating frequency of the ultrasonic transducer, and the energy corresponding to the main frequency in the echo ultrasonic signal is the main energy. When the energy corresponding to the frequency in the echo ultrasonic signal in the current time period is more concentrated towards the main energy, it indicates that the surface of the metal workpiece near the bottom of the cleaning tank and facing the ultrasonic transducer at the current moment is less rough. Therefore, this embodiment further analyzes the surface complexity of the metal workpiece at the current moment based on the size of the reference power spectrum data and the difference between each frequency in the echo ultrasonic signal and the main frequency in the current time period.

[0059] The more diverse the geometric features of the surface of the metal workpiece are, the more multi-path reflections are caused, and the more irregular the echo ultrasonic signal is in the frequency domain. Therefore, the more complex the geometric features of the surface of the metal workpiece are near the bottom of the cleaning tank and facing the ultrasonic transducer at the current time, the more chaotic the reference power spectrum data in the current time period is. Therefore, the embodiment further analyzes the surface complexity of the metal workpiece at the current time according to the chaos of the reference power spectrum data.

[0060] Therefore, the embodiment obtains the surface complexity of the metal workpiece at the current time according to the size and chaos of the reference power spectrum data, and the difference between each frequency and the main frequency in the echo ultrasonic signal in the current time period. The greater the surface complexity is, the smaller the rotation speed of the handle at the current time should be, so as to ensure that the surface of the metal workpiece is fully cleaned.

[0061] Preferably, in an implementable manner of the embodiment, the surface complexity is obtained by the method shown in Figure 2 The method comprises the following steps:

[0062] Step S201: obtaining the total energy of the echo ultrasonic signal in the current time period according to the size of the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period.

[0063] The greater the total energy is, the greater the surface of the metal workpiece near the bottom of the cleaning tank and facing the ultrasonic transducer at the current time is, which indirectly indicates that the surface of the metal workpiece near the bottom of the cleaning tank and facing the ultrasonic transducer at the current time is more complex.

[0064] The embodiment takes the result of normalizing the sum of all reference power spectrum data as the total energy of the echo ultrasonic signal in the current time period. The embodiment normalizes the sum of all reference power spectrum data by using the norm normalization function.

[0065] Step S202: obtaining the main energy concentration degree of the echo ultrasonic signal in the current time period according to the difference between each frequency and the main frequency in the echo ultrasonic signal in the current time period, and the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period.

[0066] The greater the main energy concentration degree is, the less rough the surface of the metal workpiece near the bottom of the cleaning tank and facing the ultrasonic transducer at the current time is, which indirectly indicates that the surface of the metal workpiece near the bottom of the cleaning tank and facing the ultrasonic transducer at the current time is less complex.

[0067] In one possible implementation of this embodiment, the method for obtaining the main energy concentration degree is as follows: for any frequency in the echo ultrasonic signal in the current time period, the closer the frequency is to the main frequency, the greater the proportion of the reference power spectrum data corresponding to the frequency is as the main energy. Then, in this embodiment, the absolute value of the difference between the frequency and the main frequency is negatively correlated and normalized, and the result is used as the participation weight of the frequency; wherein the calculation formula of the participation weight is: ρ k =exp(-|P k -P ′ |); where ρ k is the participation weight of the kth frequency; P k is the kth frequency; P ′ is the main frequency; || is the absolute value function; exp is the exponential function with a natural constant as the base. The product of the participation weight of the frequency and the reference power spectrum data corresponding to the frequency is used as the main energy participation value corresponding to the frequency. In order to comprehensively analyze the main energy concentration of the echo ultrasonic signal in the current time period, the main energy participation values ​​corresponding to all frequencies in the echo ultrasonic signal in the current time period are added together and normalized to obtain the main energy concentration degree of the echo ultrasonic signal in the current time period. This embodiment uses the norm normalization function to normalize the sum of the main energy participation values ​​corresponding to all frequencies in the echo ultrasonic signal in the current time period.

[0068] Step S203: obtaining the instability of the echo ultrasonic signal in the current time period according to the degree of disorder of the reference power spectrum data corresponding to all frequencies in the echo ultrasonic signal in the current time period.

[0069] Among them, the greater the degree of instability, the more complex the surface shape of the metal workpiece close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current moment, which indirectly indicates that the more complex the surface of the metal workpiece close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current moment.

[0070] To analyze the instability of the echo ultrasound signal within the current time period, this embodiment first normalizes the reference power spectrum data corresponding to each frequency in the echo ultrasound signal within the current time period. The signal entropy corresponding to the normalized reference power spectrum data is then used as the degree of instability of the echo ultrasound signal within the current time period. The method for obtaining the signal entropy is well known and will not be further described.

[0071] Step S204: Obtain the surface complexity of the metal workpiece at the current moment based on the total energy, main energy concentration and instability; wherein the total energy and instability are positively correlated with the surface complexity, and the main energy concentration is negatively correlated with the surface complexity.

[0072] The greater the total energy, the smaller the main energy concentration degree and the greater the instability degree, the more complex the surface of the metal workpiece close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current time. Therefore, the embodiment obtains the surface complexity of the metal workpiece at the current time according to the total energy, the main energy concentration degree and the instability degree. The total energy and the instability degree are positively correlated with the surface complexity, and the main energy concentration degree is negatively correlated with the surface complexity.

[0073] In actual situations, the proportions of the total energy, the main energy concentration degree and the instability degree may be different in order to more accurately obtain the surface complexity. Therefore, the embodiment sets the useful weights of the total energy, the main energy concentration degree and the instability degree. It should be noted that the sum of the useful weights of the total energy, the main energy concentration degree and the instability degree is 1.

[0074] The calculation formula of the surface complexity is F = norm (ω1 x E + ω2 x (1-Z) + ω3 x W). In the formula, F is the surface complexity of the metal workpiece at the current time, E is the total energy, Z is the main energy concentration degree, W is the instability degree, ω1 is the useful weight of the total energy, ω2 is the useful weight of the main energy concentration degree, ω3 is the useful weight of the instability degree, and norm is a normalization function.

[0075] The embodiment sets ω1, ω2 and ω3 to be The implementer can set the sizes of ω1, ω2 and ω3 according to actual situations, which are not limited here.

[0076] Step S4: adjusting the rotation speed of the rotating handle at the current time based on the surface complexity, obtaining the corrected rotation speed of the rotating handle at the current time, and performing ultrasonic cleaning on the metal workpiece.

[0077] Specifically, the greater the surface complexity of the metal workpiece at the current time, the greater and rougher the surface of the metal workpiece close to the bottom of the cleaning tank and facing the ultrasonic transducer at the current time, and the stronger the shape complexity, and the longer the cleaning time when performing ultrasonic cleaning. Therefore, the rotation speed of the rotating handle at the current time should be smaller, so as to perform more perfect cleaning on the surface of the metal workpiece. Further, the embodiment adjusts the rotation speed of the rotating handle at the current time based on the surface complexity, obtains the corrected rotation speed of the rotating handle at the current time, and performs ultrasonic cleaning on the metal workpiece, so as to sufficiently clean the surface of the metal workpiece while avoiding excessive cleaning of the surface of the metal workpiece to cause resource waste.

[0078] Preferably, in one implementation of the present embodiment, the method for obtaining the corrected rotating speed is: taking the product of the preset initial rotating speed of the rotating handle and the surface complexity as the rotating speed adjustment value of the rotating handle at the current time; wherein the preset initial rotating speed is set by the operator according to the actual situation, which is not limited herein. Then taking the difference between the preset initial rotating speed and the rotating speed adjustment value as the corrected rotating speed of the rotating handle at the current time.

[0079] According to the above method for obtaining the corrected rotating speed, the corrected rotating speed of the rotating handle at each time is obtained in real time during the ultrasonic cleaning of the metal workpiece, and then the rotating speed of the rotating handle is adjusted in real time through the motor control module, which effectively improves the sufficiency and perfection of the ultrasonic cleaning of the metal workpiece, and is beneficial to better annealing treatment of the metal workpiece. The time interval between the adjacent two times is set to 0.3 seconds in the present embodiment, and the implementer can set the time interval between the adjacent two times according to the actual situation, which is not limited herein.

[0080] When the ultrasonic cleaning of the metal workpiece is completed, the cleaned metal workpiece is transferred to the rinsing tank by the robot for rinsing to remove the cleaning liquid and cavitation bubbles and other attachments remaining in the ultrasonic cleaning process. After rinsing, the metal workpiece is transferred to the annealing bin by the robot for annealing treatment, and then rinsing and drying are performed again after annealing, and finally the annealing process of the metal workpiece is completed.

[0081] In summary, the present embodiment obtains the target ultrasonic signal in the current time period during the ultrasonic cleaning of the metal workpiece; obtains the reference power spectrum data corresponding to each frequency according to the difference between the power spectrum data corresponding to each frequency in the target ultrasonic signal and the power spectrum data; obtains the surface complexity of the metal workpiece at the current time according to the size and confusion of the reference power spectrum data, and the difference between each frequency and the main frequency, and then obtains the corrected rotating speed of the rotating handle at the current time for ultrasonic cleaning of the metal workpiece. The present application obtains the corrected rotating speed of the rotating handle at each time in real time, which effectively improves the sufficiency and perfection of the ultrasonic cleaning of the metal workpiece, and is beneficial to better annealing treatment of the metal workpiece.

[0082] It should be noted that the above-mentioned order of the embodiments of the present application is only for description, and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or may be advantageous.

[0083] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the differences from other embodiments.

Claims

1. A method for controlling ultrasonic cleaning of ceramic metal workpieces, characterized in that: The method comprises the following steps: Acquire a target ultrasonic signal in a current time period during ultrasonic cleaning of a metal workpiece; wherein the target ultrasonic signal includes a through ultrasonic signal and an echo ultrasonic signal; Obtain reference power spectrum data corresponding to each frequency in the echo ultrasonic signal within the current time period based on the difference between the power spectrum data corresponding to each frequency in the target ultrasonic signal and the representative power spectrum data; wherein the representative power spectrum data is the power spectrum data obtained by the direct ultrasonic signal; The surface complexity of the metal workpiece at the current moment is obtained based on the size and disorder of the reference power spectrum data and the difference between each frequency and the main frequency in the echo ultrasonic signal in the current time period; the main frequency is the operating frequency of the ultrasonic transducer; The rotation speed of the lower handle at the current moment is adjusted based on the surface complexity, and the corrected rotation speed of the lower handle at the current moment is obtained to perform ultrasonic cleaning on the metal workpiece; the handle is used to fix the metal workpiece in the cleaning basket and then drive the cleaning basket to rotate by rotating the handle.

2. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 1, characterized in that: The method for obtaining the data representing the power spectrum is as follows: Acquire an ultrasonic signal within a specified time period without a metal workpiece as a reference ultrasonic signal, divide the reference ultrasonic signal into time windows of preset duration, perform windowing processing on the reference ultrasonic signal in each time window using a Hanning window, and then obtain the first power spectrum data in each time window using a short-time Fourier transform; The mean value of the first power spectrum data in all time windows corresponding to the reference ultrasonic signal is used as the representative power spectrum data.

3. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 1, characterized in that: The method for obtaining the reference power spectrum data is: For any frequency in the target ultrasonic signal, obtain the difference between the power spectrum data corresponding to the frequency in the target ultrasonic signal and the characterization power spectrum data as the reference power spectrum data corresponding to the frequency in the echo ultrasonic signal in the current time period; wherein, when the reference power spectrum data is a negative number, set the reference power spectrum data to 0.

4. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 1, characterized in that: The method for obtaining the surface complexity is: Obtaining the total energy of the echo ultrasonic signal in the current time period according to the magnitude of the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period; Obtaining the main energy concentration of the echo ultrasonic signal in the current time period according to the difference between each frequency and the main frequency in the echo ultrasonic signal in the current time period and the reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period; Obtaining the instability of the echo ultrasonic signal in the current time period according to the degree of disorder of the reference power spectrum data corresponding to all frequencies in the echo ultrasonic signal in the current time period; The surface complexity of the metal workpiece at the current moment is obtained based on the total energy, main energy concentration and instability. Among them, the total energy and instability are positively correlated with the surface complexity, while the main energy concentration is negatively correlated with the surface complexity.

5. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 4, characterized in that: The method for obtaining the total energy is: The result of adding and normalizing all the reference power spectrum data is used as the total energy of the echo ultrasonic signal in the current time period.

6. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 4, characterized in that: The method for obtaining the main energy concentration degree is: For any frequency in the echo ultrasonic signal in the current time period, the result of negative correlation and normalization of the difference between the frequency and the main frequency is used as the participation weight of the frequency; The product of the participation weight of the frequency and the reference power spectrum data corresponding to the frequency is used as the main energy participation value corresponding to the frequency; The main energy participation values ​​corresponding to all frequencies in the echo ultrasonic signal in the current time period are summed and normalized, and the result is used as the main energy concentration degree of the echo ultrasonic signal in the current time period.

7. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 4, characterized in that: The method for obtaining the degree of instability is: The reference power spectrum data corresponding to each frequency in the echo ultrasonic signal in the current time period is uniformly normalized, and the signal entropy corresponding to the normalized reference power spectrum data is used as the instability degree of the echo ultrasonic signal in the current time period.

8. The ultrasonic cleaning control method for ceramic metal workpieces according to claim 1, characterized in that: The method for obtaining the corrected speed is: The product of the preset initial rotation speed of the throttle and the surface complexity is used as the rotation speed adjustment value of the throttle at the current moment; The difference between the preset initial speed and the speed adjustment value is used as the corrected speed of the throttle at the current moment.

9. The ultrasonic cleaning control method for ceramic metal workpiece according to claim 1, characterized in that: The direct ultrasonic signal is an ultrasonic signal directly emitted by the ultrasonic transducer; The echo ultrasonic signal is an ultrasonic signal corresponding to the ultrasonic wave emitted by the ultrasonic transducer after being reflected by the metal workpiece.

10. An ultrasonic cleaning device for ceramic metal workpieces, comprising an ultrasonic cleaning mechanism for ceramic metal workpieces, the ultrasonic cleaning mechanism for ceramic metal workpieces comprising an ultrasonic probe embedded in the bottom of a cleaning tank and a motor control module installed at a handle, characterized in that: The ultrasonic probe is used to obtain ultrasonic signals in the cleaning tank in real time, the motor control module is used to control the rotation speed of the handle, the output end of the ultrasonic probe is connected to the input end of the motor control module, and the ultrasonic cleaning equipment for ceramicizing metal workpieces implements the steps of an ultrasonic cleaning control method for ceramicizing metal workpieces as described in any one of claims 1 to 9 above.

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