CN116900817A - Ultrasonic processing quality control method and system for monitoring cutter wear and electronic equipment - Google Patents
Ultrasonic processing quality control method and system for monitoring cutter wear and electronic equipment Download PDFInfo
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- 238000012544 monitoring process Methods 0.000 title claims abstract description 39
- 238000003908 quality control method Methods 0.000 title claims abstract description 32
- 238000005299 abrasion Methods 0.000 claims abstract description 30
- 238000003754 machining Methods 0.000 claims abstract description 11
- 238000004364 calculation method Methods 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 42
- 238000005520 cutting process Methods 0.000 claims description 32
- 230000008569 process Effects 0.000 claims description 32
- 230000000087 stabilizing effect Effects 0.000 claims description 9
- 230000003068 static effect Effects 0.000 claims description 9
- 238000004590 computer program Methods 0.000 claims description 7
- 238000000227 grinding Methods 0.000 claims description 7
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- 238000002474 experimental method Methods 0.000 claims description 4
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- 230000001276 controlling effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
- B23Q17/09—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
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Abstract
The invention discloses an ultrasonic processing quality control method and system for monitoring cutter wear and electronic equipment, and relates to the field of machining and system control. According to the ultrasonic processing quality control method for monitoring the cutter abrasion, reactive power is controlled to be constant according to the real-time resistance of the transducer, and power tracking is achieved; according to the real-time impedance relation of the transducer, the real-time resonance frequency of the transducer is obtained through characteristic root calculation and curve fitting, and frequency tracking is achieved; the amplitude of the transducer is stable by controlling the feedback current to be constant, the stability of the ultrasonic processing effect is ensured, and the real-time steady-flow amplitude voltage of the system is obtained; on the basis of ensuring the stability of the ultrasonic processing effect by steady flow and steady amplitude, the steady flow and steady amplitude voltage of the transducer is monitored in real time to realize the monitoring of the abrasion state of the cutter, and on the premise of not using a force sensor, the accurate control of the ultrasonic processing quality is realized.
Description
Technical Field
The invention relates to the field of mechanical processing and system control, in particular to an ultrasonic processing quality control method, an ultrasonic processing quality control system and electronic equipment for monitoring cutter abrasion.
Background
The resonance control of ultrasonic processing frequency is most, and the stability control of processing quality is very little in the ultrasonic processing process. The wave type processing is an advanced ultrasonic processing method, and achieves good processing quality improvement in cutting processing, such as high-speed fine processing, cutting extrusion strengthening and the like. However, how to ensure the stability of the machining quality caused by the state of the tool during machining has become a key problem in the application of the technology to machining of large-scale integrated components.
The amplitude of ultrasonic processing is a key parameter for determining the processing quality of the ultrasonic processing, and the amplitude is changed along with the state of a cutter, and experiments show that the cutting force is increased by the state of the cutter, so that the diameter of an impedance circle of a transducer is reduced, and the amplitude of ultrasonic processing is reduced. The quality of ultrasonic processing is sensitive to variations in amplitude, so monitoring tool state and controlling amplitude stability in real time is critical to improving the vibration performance of the transducer.
After the tool state is changed, in the frequency tracking drive resonance circuit, the resonance frequency is changed to be Δf, but the resonance frequency change value Δf and the cutting force do not change monotonically, so that the tool state cannot be monitored by Δf. In a driving resonant circuit without phase lock, the impedance phase changes by a value ΔΦ, but ΔΦ does not change monotonically as the cutting force does, and therefore the tool state cannot be monitored by ΔΦ. The cutting force changes monotonically with the tool state, which can be monitored using the cutting force changes. The reasonable cutting force monitoring method is to add a force sensor on a cutting knife handle, but is limited by the problems of a rotary processing mode of the knife handle and the like, and the scheme is not practical until now. At present, the cutting force monitoring method mainly adopts means such as a dynamometer, but the dynamometer is fixed on a machine tool workbench, a special tool is required to be designed, even the machine tool structure is required to be changed, force sensors such as the dynamometer cannot be used in actual machining production, and the state monitoring of a cutter in industrial production has a lot of difficulties.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides an ultrasonic processing quality control method, an ultrasonic processing quality control system and electronic equipment for monitoring cutter wear.
In order to achieve the above object, the present invention provides the following solutions:
an ultrasonic machining quality control method for monitoring tool wear, comprising:
acquiring dynamic resistance of a transducer and dynamic reactance of the transducer in the ultrasonic processing process, and determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer to obtain a time domain impedance relation;
carrying out Laplace transformation on the time domain impedance relationship to obtain a frequency domain impedance curve of the transducer;
fitting the frequency domain impedance curve of the transducer to obtain a curve with a unique pair of conjugate characteristic roots;
the resonant frequency of the transducer is obtained in real time based on a curve with a unique pair of conjugate characteristic roots, so that frequency tracking is realized;
the method comprises the steps of acquiring dynamic total resistance and dynamic total reactance of an ultrasonic system in real time by tracking feedback current in real time, determining the duty ratio of active power and reactive power in output power by the dynamic total resistance and the dynamic total reactance of the ultrasonic system, adjusting the output power based on the duty ratio, realizing power tracking, and acquiring steady-flow and steady-amplitude voltage of the ultrasonic system in real time;
detecting the difference value between the steady-flow steady-amplitude voltage of the ultrasonic system and the steady-flow steady-amplitude voltage of the cutter in a grinding state in real time in the ultrasonic processing process, determining the cutter abrasion state based on the difference value, and judging whether the current cutter can finish the processing of the whole process or not based on the cutter abrasion state; the tool wear state includes: an empty state, a cutting new blade state and a blade sharpening state.
Optionally, before acquiring the dynamic resistance of the transducer and the dynamic reactance of the transducer during ultrasonic processing and determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer, the method further comprises:
and obtaining steady-flow amplitude stabilizing voltage and feedback current values of different cutter abrasion states at the cutting workpiece position or cutting dosage through experiments.
Optionally, the time domain impedance of the transducer is:
wherein Z is t For the time-domain impedance of the transducer at time t, R t For the dynamic resistance of the transducer at time t, X t The dynamic reactance of the transducer at the moment t, omega is the vibration angular frequency of the transducer, C 0 R is the static capacitance of the transducer 1 For dynamic resistance, L 1 Inductance of dynamic inductance, C p To account for the total capacitance value of the transducer when static capacitance, j is the imaginary sign in the complex plane.
Optionally, a series of response curve data points are obtained in an S plane at a set distance from the virtual axis by an interpolation calculation method, and a frequency domain impedance curve of the transducer is fitted according to the obtained response curve data points to obtain a curve with a unique pair of conjugate characteristic roots.
Optionally, the relation between the dynamic resistance of the transducer and the dynamic reactance of the transducer is:
wherein R is t For the dynamic resistance of the transducer at time t, X t For the dynamic reactance of the transducer at time t, ω p For parallel resonance angular frequency, C 0 R is the static capacitance of the transducer 1 Is a dynamic resistance value.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
according to the ultrasonic processing quality control method for monitoring the cutter abrasion, reactive power is controlled to be constant according to the real-time resistance of the transducer, and power tracking is achieved; according to the real-time impedance relation of the transducer, the real-time resonance frequency of the transducer is obtained through characteristic root calculation and curve fitting, and frequency tracking is achieved; the amplitude of the transducer is stable by controlling the feedback current to be constant, the stability of the ultrasonic processing effect is ensured, and the real-time steady-flow amplitude voltage of the system is obtained; on the basis of ensuring the stability of the ultrasonic processing effect by steady flow and steady amplitude, the steady flow and steady amplitude voltage of the transducer is monitored in real time to realize the monitoring of the abrasion state of the cutter, and on the premise of not using a force sensor, the accurate control of the ultrasonic processing quality is realized.
Further, the invention also provides an ultrasonic processing quality control system for monitoring the cutter abrasion, so as to apply the ultrasonic processing quality control method for monitoring the cutter abrasion; the system comprises:
the time domain impedance relation determining module is used for acquiring the dynamic resistance of the transducer and the dynamic reactance of the transducer in the ultrasonic processing process, and determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer to obtain a time domain impedance relation;
the frequency domain impedance curve determining module is used for carrying out Laplace transformation on the time domain impedance relation to obtain a frequency domain impedance curve of the transducer;
the curve fitting module is used for fitting the frequency domain impedance curve of the transducer to obtain a curve with a unique pair of conjugate characteristic roots;
the frequency tracking module is used for obtaining the resonant frequency of the transducer in real time based on a curve with a unique pair of conjugate characteristic roots and realizing frequency tracking;
the power tracking module is used for acquiring the dynamic total resistance and the dynamic total reactance of the ultrasonic system in real time through real-time tracking of the feedback current, determining the duty ratio of active power and reactive power in output power by the dynamic total resistance and the dynamic total reactance of the ultrasonic system, adjusting the output power based on the duty ratio, realizing power tracking, and acquiring the steady-flow amplitude-stabilizing voltage of the ultrasonic system in real time;
the cutter abrasion state determining module is used for detecting the difference value between the steady-flow steady-amplitude voltage of the ultrasonic system and the steady-flow steady-amplitude voltage of the cutter in the grinding state in real time in the ultrasonic processing process, determining the cutter abrasion state based on the difference value, and judging whether the current cutter can finish the processing of the whole process or not based on the cutter abrasion state; the tool wear state includes: an empty state, a cutting new blade state and a blade sharpening state.
An electronic device, comprising:
a memory for storing a computer program;
and the processor is connected with the memory and is used for calling and executing the computer program so as to implement the ultrasonic processing quality control method for monitoring the cutter abrasion.
Optionally, the memory is a computer readable storage medium.
The technical effects achieved by the two structures provided by the invention are the same as those achieved by the ultrasonic processing quality control method for monitoring cutter wear, so that the technical effects are not repeated here.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of an ultrasonic processing quality control method for monitoring tool wear provided by the invention;
FIG. 2 is a schematic diagram of an equivalent circuit model of a transducer provided by the present invention;
FIG. 3 is a schematic diagram of a circular model of transducer impedance provided by the present invention;
FIG. 4 is a schematic diagram of the amplitude stabilizing control principle provided by the invention;
FIG. 5 is a graph showing an example of the variation of the impedance circle with load according to the present invention;
fig. 6 is a flow chart of the steady control provided by the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide an ultrasonic processing quality control method, an ultrasonic processing quality control system and electronic equipment for monitoring cutter wear, which can monitor the cutter state in real time by utilizing the working state change of a transducer in the ultrasonic processing process, and control the amplitude stabilization according to the detection result so as to stabilize the ultrasonic processing process. In addition, the invention does not need to use a force sensor, and can improve the processing quality while solving the problem of monitoring the state of the cutter in the actual processing production.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in fig. 1, the ultrasonic processing quality control method for monitoring tool wear provided by the invention comprises the following steps:
step 100: and acquiring the dynamic resistance of the transducer and the dynamic reactance of the transducer in the ultrasonic processing process, and determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer to obtain a time domain impedance relationship.
In the practical application process, the ultrasonic piezoelectric transducer in ultrasonic processing is a strong nonlinear time-varying system, and the electrical characteristic of the ultrasonic piezoelectric transducer can be expressed as a form that a resistor is connected in series with a reactor, namely the impedance of the transducer is z=r+jx, wherein the reactor can be regarded as a capacitor connected in series with an inductor, and then R is the dynamic resistance of the transducer, C is the dynamic capacitance of the transducer, L is the dynamic inductance of the transducer, and X is the reactance. As shown in FIG. 2, the equivalent circuit model of the transducer is provided with a dynamic resistance value R 1 The capacitance value of the dynamic capacitor is C 1 The inductance of the dynamic inductor is L 1 Static state of transducerCapacitance C 0 The mechanical resonance frequency of the transducer is:
f is also referred to as the series resonant frequency of the transducer, and when the transducer vibrates at frequency f, the amplitude of the vibration reaches a maximum, which is an ideal processing state. As shown in FIG. 3, during wave processing, the static capacitance C of the transducer 0 Which appears as a capacitive load, needs to be compensated by an additional matching inductance. Series matching inductance L 0 The following conditions need to be satisfied:
jωL 0 +jωX p ＝0 (2)
wherein ω is the angular frequency of vibration of the transducer, X p Is the total reactance of the transducer without series inductance.
The total impedance of the resonant system at this point is:
wherein Z is t For the time-domain impedance of the transducer at time t, R t For the dynamic resistance of the transducer at time t, X t For the dynamic reactance of the transducer at time t, j is the sign of the imaginary part in the complex plane, C p To take into account the total capacitance of the transducer at static capacitance, C p ＝C 0 C 1 /(C 0 +C 1 )。
When (when)When L 1 And C p The resonant circuit is formed in the transducer, and the angular frequency at this time is called the parallel resonant angular frequency, denoted ω p . At omega p Near, the dynamic resistance R of the transducer at time t t And the dynamic reactance X of the transducer at time t t Has the following relationship:
the resistance and reactance of the resonant system at this point is plotted in a circular shape in the complex plane, known as the impedance circle. During ultrasonic processing, the cutting force increases to cause the dynamic resistance R of the transducer 1 Increasing R in the total impedance of a resonant system t And X t All of which are changed accordingly. The cutter is continuously worn in the ultrasonic processing process, so that the impedance relation of the transducer is dynamically changed in real time.
In the actual ultrasonic processing working condition, the abrasion degree of the cutter is continuously increased, so that the cutting force is continuously increased, and the dynamic resistance R of the transducer is obtained 1 The radius of the impedance circle is continuously reduced. It can be found that the change of the real-time impedance relation of the transducer is monotonous and continuous in the ultrasonic processing process, and the tracking can be realized in an ultrasonic power supply system.
Step 101: and carrying out Laplacian transformation on the time domain impedance relation to obtain a frequency domain impedance curve of the transducer.
In actual operation, the voltage applied to the two ends of the ultrasonic piezoelectric transducer is a pulse square wave, so that the transducer works in an under-inherent resonance area. The laplace transform of the transducer's time domain impedance, equation (3), yields:
where s is a differential operator.
Step 102: fitting the frequency domain impedance curve of the transducer results in a curve with a unique pair of conjugate characteristic roots. Specifically, the curve fitting process may be: a series of response curve data points are obtained in an s-plane close to the virtual axis in an interpolation calculation mode, and curve fitting is carried out according to the data points, so that a curve with a unique pair of conjugate characteristic roots can be obtained.
The frequency domain impedance curve obtained after the time domain impedance of the transducer is subjected to Laplacian transformation is a high-order curve, and the computing characteristic root speed is low. In practical application, the frequency domain impedance curve of the transducer is fitted by using a curve fitting data control algorithm and using a curve with a unique pair of conjugate characteristic roots, and the conjugate characteristic roots of the fitted curve are ensured to be the same as the main characteristic roots of the frequency domain impedance of the transducer, so that the tracking speed of the resonant frequency can be effectively increased.
Step 103: and obtaining the resonant frequency of the transducer in real time based on a curve with a unique pair of conjugate characteristic roots, and realizing frequency tracking so as to enable the ultrasonic system to be in a stable resonant state.
Wherein, the characteristic root of the formula (5) is calculated, wherein, a group of conjugate characteristic roots closest to the pole are main characteristic roots, the rest are auxiliary characteristic roots, and the resonance frequency represented by the main characteristic roots is the resonance frequency of the transducer system. The real-time impedance relation of the transducer can be rapidly obtained by the real-time tracking transducer of the ultrasonic system, namely, the time domain impedance of the transducer is obtained by the equation (5), and the resonant frequency of the transducer system can be obtained by solving the equation (5) for frequency tracking.
Based on this, the process of frequency tracking may be: the time domain impedance of the transducer system can be obtained in real time through the real-time impedance relation tracking of the transducer, and the resonance frequency of the transducer system can be obtained by solving the obtained characteristic root. According to the obtained resonant frequency, the ultrasonic power supply system can realize frequency tracking by converting the output frequency in real time to match the resonant state of the transducer.
Step 104: the dynamic total resistance and the dynamic total reactance of the ultrasonic system are obtained in real time through real-time tracking of feedback current, the duty ratio of active power and reactive power in output power is determined by the dynamic total resistance and the dynamic total reactance of the ultrasonic system, the output power is regulated based on the duty ratio, power tracking is achieved, and steady-flow amplitude stabilizing voltage of the ultrasonic system is obtained in real time.
In the practical application process, the power feedback module adjusts output power according to feedback current, controls reactive power to be constant, and acquires the dynamic total resistance R of the ultrasonic system in real time by tracking feedback current I in real time t And dynamic total reactance X t The duty ratio of active power and reactive power in the output power is calculated according to the duty ratio, so that the output power is regulated, the power tracking is realized, the feedback current and the ultrasonic amplitude value are stable, and the ultrasonic processing is ensuredThe effect is stable, and the real-time steady-flow and amplitude-stabilizing voltage of the ultrasonic system is obtained.
Wherein the active power P a The calculation formula of (2) is as follows:
wherein P is t Is the total output power of the ultrasound system.
Reactive power of P r ＝P t -P a And regulating output power according to the feedback current, controlling reactive power to be constant, and thus realizing power tracking.
Further, the adjustment process of the power tracking is as follows: in the ultrasonic machining process, the cutting force increases as the tool wears. An increase in cutting force results in a dynamic resistance R of the transducer 1 The voltage values at the two ends of the transducer are unchanged, and the output current and the feedback current are reduced. The power feedback module adjusts output power according to feedback current, so that the PWM wave duty ratio of the output voltage is increased, the feedback current value is improved, and the feedback current and ultrasonic amplitude value are stable. On the premise of stable current, the output power is regulated by changing the output voltage, and the regulated output voltage value is steady-current and stable-amplitude voltage. In actual processing, the feedback regulation process is completed in microsecond time, so that the feedback current value in the display interface is kept constant, the output voltage value changes in real time along with the cutting process, and the voltage is called as steady-flow and steady-amplitude voltage.
For example, fig. 4 is a schematic diagram of the amplitude stabilizing control principle of an embodiment of the ultrasonic processing quality control method for monitoring tool wear by stabilizing amplitude stabilizing voltage. In fig. 4, the upper right coordinate system is the portion near the series resonant frequency of the transducer impedance circular model of fig. 3. Point A 1 The circle is the impedance circle before loading, point A 2 The circle is the loaded impedance circle, the resistor R t2 >R t1 . Point A 1 And point A 2 Point 1 and point 2 of the lower right coordinate system respectively correspond. The lower right coordinate system is the current as a function of transducer resistance when the voltage is constant. Curve U' 1 Is a currentThe function curve before feedback regulation, the voltage value at two ends of the transducer is U 1 . Curve U' 2 The voltage values at two ends of the transducer are U as a function curve before current feedback adjustment 2 . Point 1 represents the state of the transducer before loading, denoted as the first state. Point 2 represents the loaded state of the transducer, denoted as second state. Point 3 represents the state after feedback adjustment of the transducer, denoted as third state. After the transducer is loaded, the diameter of the impedance circle is reduced, the resistance is increased, and the voltage value U at two ends of the transducer 1 Constant, current value is defined by I 1 Reduce to I 2 I.e. the operating state is switched from the first state to the second state. The lower left coordinate system is a triangular wave for controlling current output, and the upper left coordinate system is a PWM square wave for controlling voltage output. When the current value of the triangular wave is higher than that of the transducer, the PWM square wave outputs a high potential. In a PWM square wave, the higher the high potential duty cycle, i.e., the higher the duty cycle, the higher the voltage across the transducer. After the transducer is loaded, the current value of the transducer is represented by I 1 Reduce to I 2 The proportion of the current value in the triangular wave that is higher than the transducer current value increases, resulting in an increase in the PWM square wave duty cycle. After feedback regulation is stable, the voltage values at two ends of the energy converter are regulated by U 1 Increase to U 2 (U 1 /R t1 ＝U 2 /R t2 ) At this time, the working state of the transducer is switched to the third state, and the current value is stabilized at I 1 The current stability control is realized, and further the amplitude stabilizing control is realized. R is R t1 Is the transducer resistance in the first state, R t2 Is the transducer resistance in the second state. Wherein in FIG. 4, f 1 For loading the series resonant frequency of the front transducer, f 2 Is the series resonant frequency of the loaded transducer. In this embodiment, the left, right, up, and down are relative to the page display, and are not specific limitations of the present invention.
FIG. 5 is a graph showing the example of the impedance circle along with the load change according to the ultrasonic processing quality control method for monitoring the tool wear by steady-flow steady-amplitude voltage according to the embodiment of the invention. As shown in fig. 5, the tangent point of the transducer impedance circle and the reactance axis is below zero, which is in accordance with theory. The location marked by a circle in fig. 5 is the operating region of the transducer, i.e., around the series resonant frequency. The load is increased, the diameter of the impedance circle is continuously reduced, the impedance near the series resonance frequency is gradually increased, and the feedback current is reduced.
Step 105: in the ultrasonic processing process, the difference value between the steady-flow steady-amplitude voltage of the ultrasonic system and the steady-flow steady-amplitude voltage in the cutter grinding state is detected in real time, the cutter abrasion state is determined based on the difference value, and whether the current cutter can finish the processing of the whole process is judged based on the cutter abrasion state.
The cutter abrasion state refers to the change amount of a monitoring signal caused by the cutter abrasion degree under a certain cutting dosage. In the ultrasonic processing process, as the cutter is worn, the cutting force is increased, and under the power tracking of the ultrasonic system, the output voltage in the ultrasonic system is also increased. The output voltage changes monotonically along with the wear degree of the cutter, so that the monitoring of the wear state of the cutter is realized by adopting the output voltage, namely a steady-flow and steady-amplitude voltage monitoring mode.
Further, before ultrasonic processing, the steady-flow steady-amplitude voltage (output voltage) and the feedback current value in three states of a certain part of a cutting workpiece or a certain cutting amount are stored in an ultrasonic power supply through a pre-experiment. The three cutter wear states are specifically:
(1) Idle state: and the cutting force is zero, and the cutting force is used for calibrating the feedback current.
(2) Cutting new cutter state: the state that the cutter just starts to carry out ultrasonic processing is used for calibrating the initial steady flow and amplitude voltage.
(3) And (3) grinding the cutter to be blunt: the state of the cutter needs to be changed for calibrating the final steady flow and amplitude voltage.
In the practical application process, the judgment basis adopted by the invention is as follows: if the real-time steady flow steady amplitude voltage value is smaller than the final steady flow steady amplitude voltage value, the cutter is in an unground state. And if the real-time steady flow steady amplitude voltage value is greater than or equal to the final steady flow steady amplitude voltage value, judging that the cutter is dull.
FIG. 6 is a steady-amplitude control flow chart of the ultrasonic processing quality control method for monitoring tool wear by steady-amplitude voltage. As shown in fig. 6, after the state of the tool is changed, the cutting force is changed, so that the impedance of the transducer is increased when the transducer works near the series resonant frequency, at this time, a feedback current signal in the feedback circuit is input into the power tracking and frequency tracking module, the power tracking module adjusts the output power in real time, the frequency tracking module transmits the signal to the curve fitting module to track the resonant frequency, and finally the PWM wave frequency and the duty ratio of the output voltage are adjusted through the processor. The output current of the energy converter is stabilized through the feedback regulation mode in the wave-type processing process, and the effect of stabilizing amplitude control is achieved.
Furthermore, the invention also provides an ultrasonic processing quality control system for monitoring the cutter abrasion, so as to apply the ultrasonic processing quality control method for monitoring the cutter abrasion. The system comprises:
the time domain impedance relation determining module is used for acquiring the dynamic resistance of the transducer and the dynamic reactance of the transducer in the ultrasonic processing process, determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer, and obtaining the time domain impedance relation.
And the frequency domain impedance curve determining module is used for carrying out Laplacian transformation on the time domain impedance relation to obtain a frequency domain impedance curve of the transducer.
And the curve fitting module is used for fitting the frequency domain impedance curve of the transducer to obtain a curve with a unique pair of conjugate characteristic roots.
And the frequency tracking module is used for obtaining the resonant frequency of the transducer in real time based on a curve with a unique pair of conjugate characteristic roots and realizing frequency tracking.
The power tracking module is used for acquiring the dynamic total resistance and the dynamic total reactance of the ultrasonic system in real time through real-time tracking of the feedback current, determining the duty ratio of active power and reactive power in the output power by the dynamic total resistance and the dynamic total reactance of the ultrasonic system, adjusting the output power based on the duty ratio, realizing power tracking, and acquiring the steady-flow and steady-amplitude voltage of the ultrasonic system in real time.
The cutter abrasion state determining module is used for detecting the difference value between the steady-flow steady-amplitude voltage of the ultrasonic system and the steady-flow steady-amplitude voltage of the cutter in the grinding state in real time in the ultrasonic processing process, determining the cutter abrasion state based on the difference value, and judging whether the current cutter can finish the processing of the whole process or not based on the cutter abrasion state. The tool wear state includes: an empty state, a cutting new blade state and a blade sharpening state.
An electronic device, comprising:
and a memory for storing a computer program.
And the processor is connected with the memory and is used for retrieving and executing a computer program to implement the ultrasonic processing quality control method for monitoring the cutter wear.
Furthermore, the computer program in the above-described memory may be stored in a computer-readable storage medium when it is implemented in the form of a software functional unit and sold or used as a separate product. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (8)
1. An ultrasonic machining quality control method for monitoring tool wear, comprising:
acquiring dynamic resistance of a transducer and dynamic reactance of the transducer in the ultrasonic processing process, and determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer to obtain a time domain impedance relation;
carrying out Laplace transformation on the time domain impedance relationship to obtain a frequency domain impedance curve of the transducer;
fitting the frequency domain impedance curve of the transducer to obtain a curve with a unique pair of conjugate characteristic roots;
the resonant frequency of the transducer is obtained in real time based on a curve with a unique pair of conjugate characteristic roots, so that frequency tracking is realized;
the method comprises the steps of acquiring dynamic total resistance and dynamic total reactance of an ultrasonic system in real time by tracking feedback current in real time, determining the duty ratio of active power and reactive power in output power by the dynamic total resistance and the dynamic total reactance of the ultrasonic system, adjusting the output power based on the duty ratio, realizing power tracking, and acquiring steady-flow and steady-amplitude voltage of the ultrasonic system in real time;
detecting the difference value between the steady-flow steady-amplitude voltage of the ultrasonic system and the steady-flow steady-amplitude voltage of the cutter in a grinding state in real time in the ultrasonic processing process, determining the cutter abrasion state based on the difference value, and judging whether the current cutter can finish the processing of the whole process or not based on the cutter abrasion state; the tool wear state includes: an empty state, a cutting new blade state and a blade sharpening state.
2. The ultrasonic machining quality control method of monitoring tool wear of claim 1, wherein prior to acquiring dynamic resistance of a transducer and dynamic reactance of a transducer during ultrasonic machining and determining a time domain impedance of a transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer, the method further comprises:
and obtaining steady-flow amplitude stabilizing voltage and feedback current values of different cutter abrasion states at the cutting workpiece position or cutting dosage through experiments.
3. The ultrasonic processing quality control method for monitoring tool wear of claim 1, wherein the transducer has a time domain impedance of:
wherein Z is t For the time-domain impedance of the transducer at time t, R t For the dynamic resistance of the transducer at time t, X t The dynamic reactance of the transducer at the moment t, omega is the vibration angular frequency of the transducer, C 0 R is the static capacitance of the transducer 1 For dynamic resistance, L 1 Inductance of dynamic inductance, C p To account for the total capacitance value of the transducer when static capacitance, j is the imaginary sign in the complex plane.
4. The ultrasonic processing quality control method for monitoring tool wear according to claim 1, wherein a series of response curve data points are obtained in an S-plane at a set distance from a virtual axis by an interpolation calculation method, and a frequency domain impedance curve of the transducer is fitted according to the obtained response curve data points to obtain a curve having a unique pair of conjugate characteristic roots.
5. The ultrasonic processing quality control method for monitoring tool wear according to claim 1, wherein the relation between the dynamic resistance of the transducer and the dynamic reactance of the transducer is:
wherein R is t For the dynamic resistance of the transducer at time t, X t For the dynamic reactance of the transducer at time t, ω p For parallel resonance angular frequencyRate C 0 R is the static capacitance of the transducer 1 Is a dynamic resistance value.
6. An ultrasonic processing quality control system for monitoring tool wear, characterized in that an ultrasonic processing quality control method for monitoring tool wear according to any one of claims 1 to 5 is applied; the system comprises:
the time domain impedance relation determining module is used for acquiring the dynamic resistance of the transducer and the dynamic reactance of the transducer in the ultrasonic processing process, and determining the time domain impedance of the transducer in real time based on the dynamic resistance of the transducer and the dynamic reactance of the transducer to obtain a time domain impedance relation;
the frequency domain impedance curve determining module is used for carrying out Laplace transformation on the time domain impedance relation to obtain a frequency domain impedance curve of the transducer;
the curve fitting module is used for fitting the frequency domain impedance curve of the transducer to obtain a curve with a unique pair of conjugate characteristic roots;
the frequency tracking module is used for obtaining the resonant frequency of the transducer in real time based on a curve with a unique pair of conjugate characteristic roots and realizing frequency tracking;
the power tracking module is used for acquiring the dynamic total resistance and the dynamic total reactance of the ultrasonic system in real time through real-time tracking of the feedback current, determining the duty ratio of active power and reactive power in output power by the dynamic total resistance and the dynamic total reactance of the ultrasonic system, adjusting the output power based on the duty ratio, realizing power tracking, and acquiring the steady-flow amplitude-stabilizing voltage of the ultrasonic system in real time;
the cutter abrasion state determining module is used for detecting the difference value between the steady-flow steady-amplitude voltage of the ultrasonic system and the steady-flow steady-amplitude voltage of the cutter in the grinding state in real time in the ultrasonic processing process, determining the cutter abrasion state based on the difference value, and judging whether the current cutter can finish the processing of the whole process or not based on the cutter abrasion state; the tool wear state includes: an empty state, a cutting new blade state and a blade sharpening state.
7. An electronic device, comprising:
a memory for storing a computer program;
a processor, coupled to the memory, for retrieving and executing the computer program to implement the ultrasonic machining quality control method of monitoring tool wear as claimed in any one of claims 1-5.
8. The electronic device of claim 7, wherein the memory is a computer-readable storage medium.
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| CN117506109A (en) * | 2023-12-22 | 2024-02-06 | 广东工程职业技术学院 | Method for improving welding power and stability of digital ultrasonic welding power supply |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117506109A (en) * | 2023-12-22 | 2024-02-06 | 广东工程职业技术学院 | Method for improving welding power and stability of digital ultrasonic welding power supply |
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