Micro-EDM gap state detection system and method

Abstract

The application relates to a micro-electrical discharge machining gap state detection system and method. The system comprises a pulse peak voltage identification module capable of generating different micro-electrical discharge machining energy field scenarios, outputting multiple voltage signals corresponding to different pulse peak voltage grades, and comparing the multiple voltage signals with preset comparison voltages to obtain first comparison results; a comparator real-time calculation module capable of obtaining a reference voltage according to the first comparison results, comparing the reference voltage with a sampling peak voltage, and obtaining second comparison results; and a time sequence signal determination and parallel driving and discrimination module capable of identifying the pulse type of the sampling peak voltage based on the processed second comparison results, obtaining a gap open circuit rate, an effective rate and a short circuit rate in a preset period based on the identification results, and determining the target gap. Thus, the problem that the existing detection technology has a lag in response to the discharge state, poor real-time performance and loss of part of the discharge information is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of special processing, in particular to a micro-EDM gap state detection system and method. BACKGROUND

[0002] In the micro-EDM process, ensuring that the tool electrode and the workpiece maintain a suitable gap is the basic prerequisite for realizing continuous and stable processing. Therefore, the performance of the gap discharge state detection link directly affects the stability and processing quality of the processing process. Since there is no arc discharge in the micro-EDM process, only the open circuit state (no-load pulse), spark discharge state (working pulse) and short circuit state (short circuit pulse) need to be detected.

[0003] In related technologies, the commonly used detection methods are average gap voltage detection method and gap peak voltage detection method. The front-end sampling circuit of these two methods is an RC sampling circuit composed of a capacitor and a resistor, and the time constant τ=RC is determined by the capacitor value and the resistor value.

[0004] However, the larger the time constant τ of such a detection circuit structure, the higher the average degree of the signal, and the more stable the detection. However, the response to the discharge state is lagging, the real-time performance is poor, and some real discharge information is lost, which needs to be solved urgently. SUMMARY

[0005] The present application provides a micro-EDM gap state detection system and method to solve the problem that the response to the discharge state in the existing detection technology is lagging, the real-time performance is poor, and some discharge information is lost, so as to ensure that the detection result has higher accuracy and real-time performance, and improve the stability and processing quality of micro-EDM.

[0006] To achieve the above purpose, the first aspect of the present application provides a micro-EDM gap state detection system, comprising: a pulse peak voltage identification module, a comparator real-time calculation module and a timing signal parallel driving and discrimination module, wherein,

[0007] The pulse peak voltage identification module is used to generate pulse peak voltage levels of different micro-EDM energy scenarios, output a plurality of voltage signals corresponding to the pulse peak voltage levels of the different micro-EDM energy scenarios, and compare the plurality of voltage signals with a preset comparison voltage to obtain a first comparison result;

[0008] The comparator real-time calculation module is used to obtain a reference voltage according to the first comparison result, compare the reference voltage with a sampling peak voltage to obtain a second comparison result, and input the second comparison result to the timing signal parallel driving and discrimination module after electrical isolation processing in the form of high and low levels.

[0009] The timing signal parallel driving and discrimination module is configured to identify the pulse type of the sampling peak voltage based on the processed second comparison result, and obtain the gap open circuit rate, the gap effective rate and the gap short circuit rate within a preset period based on the identification result, so as to determine the target gap according to the gap open circuit rate, the gap effective rate and the gap short circuit rate.

[0010] According to an embodiment of the present application, the pulse peak voltage identification module comprises:

[0011] A pulse peak voltage generation circuit is configured to generate pulse peak voltage levels of the different micro-EDM energy scenarios;

[0012] A voltage dividing resistor is configured to output a plurality of voltage signals corresponding to the pulse peak voltage levels of the different micro-EDM energy scenarios;

[0013] First to N comparators are configured to respectively compare the plurality of voltage signals with the preset comparison voltage to obtain N-1 binary comparison results, and generate the first comparison result according to the N-1 binary comparison results, wherein N is greater than or equal to 2 and is an integer.

[0014] According to an embodiment of the present application, the comparator real-time calculation module comprises a multiplexer, a nanosecond-level high-speed comparator and a first optoelectronic coupling element, wherein

[0015] The multiplexer is configured to obtain the reference voltage according to the first comparison result;

[0016] The nanosecond-level high-speed comparator is configured to compare the reference voltage with the sampling peak voltage to obtain the second comparison result, and input the second comparison result in the form of high and low levels to the timing signal parallel driving and discrimination module after electrical isolation processing by the first optoelectronic coupling element.

[0017] According to an embodiment of the present application, the timing signal parallel driving and discrimination module comprises:

[0018] A host computer is configured to set the pulse width and pulse interval time length of the gap discharge pulse as a preset pulse width and pulse interval time length;

[0019] A pulse power microcontroller is configured to generate a timing signal for controlling the on-off of a MOSFET according to the preset pulse width and pulse interval time length;

[0020] A second optoelectronic coupling element is configured to perform parallel transmission of the timing signal.

[0021] a MOSFET driver configured to control the MOSFET on-time duration to meet the preset pulse width pulse duration based on the timing signal;

[0022] a detection circuit microcontroller configured to identify a pulse type of the sampling peak voltage according to the processed second comparison result within the preset pulse width pulse duration, to obtain an identification result;

[0023] a PMAC (Programmable Multi-Axis Controller) control card configured to perform real-time cumulative counting according to the identification result, and calculate the gap open rate, the gap effective rate and the gap short circuit rate within the preset period according to the cumulative counting result, to determine the target gap according to the gap open rate, the gap effective rate and the gap short circuit rate.

[0024] According to an embodiment of the present application, the pulse type includes an open circuit pulse, an effective pulse and a short circuit pulse.

[0025] According to an embodiment of the present application, the preset comparison voltage is obtained from a middle value of adjacent two voltage signals in the plurality of voltage signals.

[0026] According to an embodiment of the present application, the sampling peak voltage is a rising edge height of a gap discharge waveform.

[0027] The gap state detection system for micro-EDM processing according to the embodiments of the present application generates pulse peak voltage levels of different micro-EDM processing energy scenarios by using a pulse peak voltage identification module, and outputs a plurality of sampling peak voltages corresponding to the pulse peak voltage levels of different micro-EDM processing energy scenarios, and respectively compares the plurality of sampling peak voltages with a preset comparison voltage to obtain a first comparison result. A comparator real-time calculation module obtains a reference voltage according to the first comparison result, compares the reference voltage with the sampling peak voltage to obtain a second comparison result, and inputs the second comparison result in the form of high and low levels to a timing signal parallel driving and discrimination module after electrical isolation processing. The timing signal parallel driving and discrimination module identifies the pulse type of the sampling peak voltage based on the processed second comparison result, and obtains the gap open rate, the gap effective rate and the gap short circuit rate within the preset period based on the identification result, to determine the target gap. Thus, the problem of existing detection technology that the response to the discharge state is delayed, the real-time performance is poor, and part of the discharge information is lost is solved, the accuracy and real-time performance of the detection result are ensured, and the stability and processing quality of the micro-EDM processing are improved.

[0028] To achieve the above object, the second aspect of the present application proposes a micro-EDM gap state detection method, which uses the micro-EDM gap state detection system of the first aspect of the present application. The method comprises the following steps:

[0029] The pulse peak voltage identification module generates pulse peak voltage levels of the different micro-EDM energy scenarios, outputs a plurality of voltage signals corresponding to the pulse peak voltage levels of the different micro-EDM energy scenarios, and compares the plurality of voltage signals with the preset comparison voltage to obtain the first comparison result.

[0030] The comparator real-time calculation module obtains the reference voltage according to the first comparison result, compares the reference voltage with the sampling peak voltage to obtain the second comparison result, and inputs the second comparison result in the form of high and low levels after electrical isolation processing to the time sequence signal parallel driving and discrimination module.

[0031] The time sequence signal parallel driving and discrimination module identifies the pulse type of the sampling peak voltage based on the processed second comparison result, and obtains the gap open circuit rate, the gap efficiency and the gap short circuit rate in the preset period based on the identification result, so as to determine the target gap according to the gap open circuit rate, the gap efficiency and the gap short circuit rate.

[0032] According to one embodiment of the present application, identifying the pulse type of the sampling peak voltage based on the processed second comparison result comprises:

[0033] Identifying a first voltage set in the sampling peak voltage that is less than or equal to a first reference voltage, and identifying a second voltage set in the sampling peak voltage that is greater than a second reference voltage, and obtaining a duration that the sampling peak voltage is greater than the second reference voltage, wherein the second reference voltage is greater than the first reference voltage.

[0034] Determining the pulse type of the sampling peak voltage in the first voltage set as a short circuit pulse, determining the pulse type of the sampling peak voltage in the second voltage set whose duration is greater than or equal to a preset duration as an open circuit pulse, and determining the pulse type of the sampling peak voltage in the second voltage set whose duration is less than the preset duration as an effective pulse.

[0035] According to one embodiment of the present application, before identifying the first voltage set in the sampling peak voltage that is less than or equal to the first reference voltage, the method further comprises:

[0036] determining a first empirical coefficient, a peak voltage of the empty carrier wave, and a second empirical coefficient;

[0037] The first reference voltage is calculated based on a product of the first empirical coefficient and the peak voltage of the empty carrier wave, and the second reference voltage is calculated based on a product of the second empirical coefficient and the peak voltage of the empty carrier wave.

[0038] The micro-EDM gap state detection method according to the embodiments of the present application can solve the problem of the existing detection technology that the response to the discharge state is delayed and the real-time performance is poor, and part of the discharge information is lost, through the micro-EDM gap state detection system, so as to ensure that the detection result has higher accuracy and real-time performance, and improve the stability and processing quality of micro-EDM.

[0039] Additional aspects and advantages of the present application will be described in the following description and further will appear upon examination of the description. BRIEF DESCRIPTION OF DRAWINGS

[0040] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0041] Figure 1 A block schematic diagram of a micro-EDM gap state detection system according to an embodiment of the present application is shown in FIG. 1;

[0042] Figure 2 A hardware framework schematic diagram of a micro-EDM gap state detection system according to an embodiment of the present application is shown in FIG. 2;

[0043] Figure 3 A micro-EDM gap state detection principle schematic diagram according to an embodiment of the present application is shown in FIG. 3;

[0044] Figure 4 A flowchart of a micro-EDM gap state detection method according to an embodiment of the present application is shown in FIG. 4;

[0045] Figure 5 A flowchart of another micro-EDM gap state detection method according to an embodiment of the present application is shown in FIG. 5. DETAILED DESCRIPTION

[0046] The embodiments of the present application are described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the drawings, in which the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0047] A micro-EDM gap state detection system and method according to an embodiment of the present application is described below with reference to the accompanying drawings.

[0048] Figure 1 A block diagram of a micro-EDM gap state detection system according to an embodiment of the present application is shown.

[0049] Before introducing the micro-EDM gap state detection system according to an embodiment of the present application, the related technical background is introduced.

[0050] The commonly used detection methods in industrial applications are average gap voltage detection method and gap peak voltage detection method. The front-end sampling circuits of the two methods are both RC sampling circuits composed of capacitors and resistors, and the time constant τ=RC is determined by the capacitor value and the resistor value. There is an inherent contradiction in the structure of such detection circuits, that is, the larger the time constant τ, the higher the signal average degree, and the more stable the detection, but the response to the discharge state lags behind, the real-time performance is poor, and part of the real discharge information is lost because the fast changing part of the signal is covered by the averaging process; on the contrary, the smaller the time constant τ, the lower the signal average degree, the more sensitive the detection, and the small changes in the discharge state can be quickly captured and responded, which is beneficial to improve the real-time performance and tracking performance of the system, but the filtering ability of high-frequency interference is weakened, because the fast response circuit cannot effectively smooth out these interference signals, which will lead to false judgment of the detection system, thereby affecting the stability of the machining process.

[0051] Optocouplers are usually used in micro-EDM gap state detection circuits to isolate the high-voltage analog signal of the discharge gap from the low-voltage digital circuit of the microcontroller, preventing high-voltage interference or damage to the low-voltage circuit. Although the optocoupler device provides good real-time performance with its tens of nanosecond propagation delay, the linear response region of the optocoupler is relatively narrow, which means that the input gap state signal must exceed a certain threshold voltage to trigger transmission; in addition, even if the input signal exceeds the threshold voltage, the change between the output signal and the input signal is not completely proportional. In the detection circuit currently used in industrial applications, directly using the optocoupler to transmit the time-varying voltage signal of the gap will affect the accuracy and authenticity of signal transmission. An alternative solution is to replace the optocoupler with an isolation module component with better linearity and temperature drift characteristics, but the response time of the current isolation module is in milliseconds, which can ensure the accuracy of signal transmission, but at the expense of real-time performance.

[0052] Based on the above problems, this application proposes a micro-electrical discharge machining gap state detection system, which can process the empty carrier waveform and gap discharge waveform of the pulse power supply output in parallel and synchronously. The designed single-pulse discrimination program distinguishes and counts open-circuit pulses, effective pulses and short-circuit pulses by comparing the reference voltage and calculating the duration of the sampling peak voltage. This allows the optocoupler components to work in a linear region with only high and low levels, which can adaptively match the pulse power supply output parameters. At the same time, it takes into account the accuracy and real-time performance of gap detection, thereby improving the stability and processing quality of micro-electrical discharge machining.

[0053] For example, such as Figure 1 As shown, the micro-electrical discharge machining gap state detection system 10 includes: a pulse peak voltage identification module 100, a comparator real-time calculation module 200, and a timing signal parallel driving and discrimination module 300. The pulse peak voltage identification module 100 generates pulse peak voltage levels for different micro-electrical discharge machining energy scenarios and outputs multiple voltage signals corresponding to these levels. It then compares these multiple voltage signals with a preset comparison voltage to obtain a first comparison result. The comparator real-time calculation module 200 obtains a reference voltage based on the first comparison result and compares the reference voltage with the sampled peak voltage to obtain a second comparison result. The second comparison result is electrically isolated in high and low voltage form and then input to the timing signal parallel driving and discrimination module 300. The timing signal parallel driving and discrimination module 300 identifies the pulse type of the sampled peak voltage based on the processed second comparison result and obtains the gap open circuit rate, gap efficiency, and gap short circuit rate within a preset period based on the identification result. The target gap is then determined based on these parameters.

[0054] That is, the pulse peak voltage identification module 100 can set multiple different pulse peak voltage levels for multiple different micro-EDM energy scenarios, and each pulse peak voltage level corresponds to a pulse peak voltage that can be obtained after being divided by the voltage dividing resistor, and multiple voltage signals (i.e., low-voltage signals) can be obtained, and the multiple voltage signals can be input into the comparator group for comparison one by one to obtain a first comparison result; the comparator real-time calculation module 200 can output a reference voltage matched with the first comparison result, and the reference voltage can be compared with a sampling peak voltage (i.e., a discharge gap real-time pulse voltage sampling signal) to obtain a second comparison result, and the second comparison result can be processed in the form of high and low levels to be electrically isolated and then input into the timing signal parallel driving and discrimination module 300 for data processing and analysis; the timing signal parallel driving and discrimination module 300 can identify the type of the sampling peak voltage based on the size and duration of the sampling peak voltage within a preset pulse width and interval, calculate the gap open rate, the gap efficiency and the gap short circuit rate within a preset period according to the identification result, and determine the target gap, adjust the gap size, and maintain the best discharge state.

[0055] Optionally, in some embodiments, the pulse types include open circuit pulses, effective pulses and short circuit pulses.

[0056] It can be understood that the open circuit pulse is also called the empty load pulse, that is, the discharge gap is not broken down, there is a voltage greater than 50V on the gap, but no current flows in the gap, and the gap is in an empty state; the effective pulse is also called the working pulse (spark discharge), that is, the dielectric state in the discharge gap is good, and the working liquid medium can be effectively thrown out and etched after being broken down; the short circuit pulse is that the discharge gap is directly short-circuited, the current is large when the gap is short-circuited, but the voltage between the two ends of the gap is very small, and there is no etching for the working purpose.

[0057] In other processes such as EDM that require pulse discharge, by effectively identifying the sampling peak voltage of different pulse types, fault early warning and rapid diagnosis can be achieved, and engineers and technical personnel can optimize process parameters to obtain better processing effect.

[0058] For ease of understanding, the following will be described in combination with Figure 2 The pulse peak voltage identification module 100, the comparator real-time calculation module 200 and the timing signal parallel driving and discrimination module 300 will be described in detail.

[0059] Optionally, in some embodiments, the pulse peak voltage identification module 100 includes: a pulse peak voltage generation circuit 101, a voltage dividing resistor R ES and first to N comparators, wherein the pulse peak voltage generation circuit 101 is configured to generate pulse peak voltage levels for different micro-EDM energy scenarios; the voltage dividing resistor R ESThis is used to output multiple voltage signals corresponding to the pulse peak voltage levels of different micro-electrical discharge machining energy scenarios; the first to Nth comparators are used to compare the multiple voltage signals with the preset comparison voltage to obtain N-1 binary comparison results, and generate the first comparison result based on the N-1 binary comparison results, where N is greater than or equal to 2 and N is an integer.

[0060] In some embodiments, the preset comparison voltage is obtained from the median value of two adjacent voltage signals among a plurality of voltage signals.

[0061] Specifically, the pulse peak voltage generation circuit 101 can be set with multiple pulse peak voltage levels of different sizes to be used in multiple different micro-electrical discharge machining energy scenarios. The pulse peak voltage corresponding to each pulse peak voltage level is divided by a voltage divider resistor R. ES After voltage division, the corresponding voltage signal (i.e., low-voltage signal) is obtained. This voltage signal is then input into multiple parallel comparators (number 1 through 1N) and compared one by one with preset comparison voltages. The N preset comparison voltages corresponding to the first through 1N comparators are obtained from the median value of two adjacent voltage signals and are used to locate the interval to which the acquired voltage signal belongs. The first through 1N comparators can output N-1 channels of binary comparison results (i.e., N-bit binary numbers, with a total of 2...). N-1 There are several combinations, and a corresponding truth table (i.e., the first comparison result) is constructed based on the N-1 binary comparison results. That is, all binary results and their corresponding pulse peak voltage levels are listed. When a binary result is received, the selected pulse peak voltage level can be automatically identified by querying the truth table.

[0062] For example, such as Figure 2 As shown, the pulse peak voltage generation circuit 101 can be set with five different pulse peak voltage levels, for example, E1 = 160V, E2 = 130V, E3 = 100V, E4 = 70V, and E5 = 40V. The pulse peak voltage corresponding to each pulse peak voltage level is divided by the voltage divider resistor R. ES After voltage division, corresponding voltage signals (i.e., low-voltage signals) can be obtained, for example, E1' = 4.7V, E2' = 3.8V, E3' = 2.9V, E4' = 2.1V, and E5' = 1.2V. Simultaneously, four comparators can be set, with the first to fourth comparators C1 to C4 corresponding to four preset comparison voltages U. E1 ~U E4 It can be obtained from the median value of two adjacent voltage signals among multiple voltage signals, for example, U E1 =4.25V (i.e., (4.7+3.8) / 2=4.25), U E2 =3.35V (i.e., (3.8+2.9) / 2=3.35), U E3=2.5V (i.e., (2.9+2.1) / 2=2.5), U E4 =1.65V (i.e., (2.1+1.2) / 2=1.65). The voltage signal is input into the four parallel comparators C1-C4 and compared one by one with a preset comparison voltage to determine the current voltage signal's range. The four comparators C1-C4 can output three binary comparison results: CH_A, CH_B, and CH_C (a total of 2). 3 =8 combinations). Based on the comparator's operating mode, assuming the input voltage signal is E1' = 4.7V, it is higher than U. E1 ~U E4 Therefore, the output of all comparators will be low (0), indicating that the input voltage is higher than the preset comparison voltage. The three binary comparison results will be CH_A=0, CH_B=0, CH_C=0, indicating that the branch where E1 is located is connected.

[0063] It should be noted that if there are more than five pulse peak voltage levels, the number of comparators can be increased to build a larger truth table, thereby enabling automatic identification of the selected pulse peak voltage level.

[0064] Alternatively, in some embodiments, such as Figure 2 As shown, the comparator real-time calculation module 200 includes: a multiplexer 201, a nanosecond-level high-speed comparator C0, and a first optocoupler 202. The multiplexer 201 is used to obtain a reference voltage based on a first comparison result. The nanosecond-level high-speed comparator C0 is used to compare the reference voltage with the sampled peak voltage to obtain a second comparison result. The second comparison result is then electrically isolated by the first optocoupler 202 in the form of high and low levels before being input to the MOSFET timing signal parallel drive and discrimination module 300.

[0065] In some embodiments, the sampling peak voltage is the rising edge height of the gap discharge waveform.

[0066] Specifically, the multiplexer 201 can output a reference voltage that matches the identified pulse peak voltage level, and input the current reference voltage to one end of the nanosecond-level high-speed comparator C0. Simultaneously, the other end of the nanosecond-level high-speed comparator C0 receives a voltage input through resistor R. GS After voltage division, the sampled peak voltage is compared with the reference voltage by the nanosecond-level high-speed comparator C0 to obtain a second comparison result. The second comparison result is then electrically isolated by the first optocoupler 202 in the form of high and low levels before being input to the timing signal parallel drive and discrimination module 300.

[0067] For example, such as Figure 2As shown, the multiplexer 201 can output a reference voltage U that matches the identified pulse peak voltage level. ref , among which, U ref =S·E (S is an empirical coefficient, E is the peak voltage of the power supply's idle carrier waveform, i.e., the voltage across the resistor R corresponding to the pulse peak voltage level) ES (Voltage signal after voltage division), for example, when the empirical coefficient S is set to 1 / 2, the reference voltage corresponding to each pulse peak voltage level is U. ref1 =S·E1'=2.35V, U ref2 =S·E2'=1.9V,U ref3 =S·E3'=1.45V, U ref4 =S·E4'=1.05V, U ref5 =S·E5'=0.6V, the current reference voltage U ref The input is given to one end of a nanosecond-level high-speed comparator C0 (such as the LM393DR2G nanosecond-level high-speed comparator with a response time of 300ns), and the other end of the nanosecond-level high-speed comparator C0 is simultaneously input through a resistor R. GS After voltage division, the sampled peak voltage is compared with the reference voltage by the nanosecond-level high-speed comparator C0 to obtain a second comparison result. The second comparison result is then electrically isolated by the first optocoupler 202 in the form of high and low levels before being input to the timing signal parallel drive and discrimination module 300 for data analysis and processing.

[0068] Understandably, by integrating a nanosecond-level comparator into the front-end sampling circuit, the detection accuracy of micro-energy pulse power supplies used in micro-electrical discharge machining is optimized. In particular, when processing pulse signals with pulse widths and intervals on the order of several microseconds, the use of nanosecond-level comparators significantly improves the response speed and accuracy of signal processing, ensuring that the detection results have higher accuracy and reliability.

[0069] Optionally, in some embodiments, the timing signal parallel driving and discrimination module 300 includes: a host computer 301, a pulse power supply microcontroller 302, a second optocoupler 303, a MOSFET driver 304, a detection circuit microcontroller 305, and a PMAC control card 306. The host computer 301 is used to set the pulse width and inter-pulse duration of the gap discharge pulse to a preset pulse width and inter-pulse duration; the pulse power supply microcontroller 302 is used to generate timing signals for controlling the on / off state of the MOSFET according to the preset pulse width and inter-pulse duration; the second optocoupler 303 is used to transmit the timing signals in parallel; M The OSFET driver 304 is used to control the pulse interval duration for deionization of the MOSFET connection time based on the timing signal to meet the preset pulse width pulse interval duration; the detection circuit microcontroller 305 is used to identify the pulse type of the sampled peak voltage according to the processed second comparison result within the preset pulse width pulse interval duration, and obtain the identification result; the PMAC control card 306 performs real-time accumulation counting according to the identification result, and calculates the gap open circuit rate, gap efficiency and gap short circuit rate within the preset period according to the accumulation counting result, so as to determine the target gap according to the gap open circuit rate, gap efficiency and gap short circuit rate.

[0070] Specifically, due to the sampling peak voltage U pp The pulses containing zero voltage need to be distinguished in terms of pulse width and eliminated in terms of pulse duration. The pulse width and pulse duration of the gap discharge pulse are set in the host computer 301 to the preset pulse width and pulse duration t. M Subsequently, the input is sent to the pulse power supply microcontroller 302 (such as a Tr-RC type pulse power supply microcontroller) to generate a timing signal for controlling the on / off state of the MOSFET. This timing signal is transmitted in parallel to the MOSFET driver 304 and the detection circuit microcontroller 305 through the second optocoupler 303. The MOSFET driver 304 controls the pulse interval time for MOSFET on / off deionization to meet the preset pulse width and pulse interval time t. M The detection circuit microcontroller 305 is used to limit the preset pulse width and pulse duration t. M The sampled peak voltage is processed and calculated internally. A pulse type discrimination program is embedded in the microcontroller 305 of the detection circuit to determine the sampled peak voltage U. pp The pulse type is identified.

[0071] The principle of the pulse type discrimination program is as follows: Figure 3 As shown, the gap discharge waveform using a Tr-RC pulse power supply can be divided into three types: open-circuit pulse, active pulse, and short-circuit pulse. The sampling peak voltage U of the short-circuit pulse... pp (That is, the rising edge height of the gap discharge waveform) is less than the peak voltage E of the power supply empty carrier waveform. Therefore, a reference voltage U is selected. ref= S·E, if the sampling peak voltage U pp is less than the reference voltage U ref (experience coefficient S = 1 / 2), the pulse type of the sampling peak voltage U pp is determined as a short-circuit pulse; the sampling peak voltage U pp of an effective pulse is equal to the peak voltage E of the power supply no-load waveform, but the pulse width duration is less than the pulse width of the power supply no-load waveform, thus, during the pulse width of the power supply no-load waveform (i.e. within the preset pulse width duration), the sampling peak voltage U ref is greater than the reference voltage U pp (experience coefficient S' = 7 / 8), the timing starts, until the sampling peak voltage U ref is less than the reference voltage U W ', the timing ends, if the timing duration t M is less than the preset duration T·t M , the pulse type of the sampling peak voltage U pp is determined as an effective pulse; the open-circuit pulse is the same as the power supply no-load waveform, i.e. the sampling peak voltage and the pulse width duration corresponding to the open-circuit pulse are equal to the peak voltage E and the pulse width t ref of the power supply no-load waveform respectively, thus, an indirect judgment method is adopted, i.e. the power supply no-load waveform is subtracted from the square waveforms representing the number of short-circuit pulses and the number of effective pulses in turn, and the remaining waveform is the square waveform representing the number of open-circuit pulses.

[0072] Based on the above identification principle, if the sampling peak voltage U pp is greater than the reference voltage U pp (experience coefficient = 1 / 2), the pulse type of the sampling peak voltage U ref is an open-circuit pulse or an effective pulse, otherwise, it is a short-circuit pulse; if the sampling peak voltage U W is greater than the reference voltage U M (experience coefficient = 7 / 8), the pulse type of the sampling peak voltage U pp is an effective pulse, otherwise, it is an open-circuit pulse. The detection circuit microcontroller 305 inputs the identification result (i.e. the pulse type of the sampling peak voltage) to the hand wheel encoder port of the PMAC control card 306 for real-time cumulative counting, so that the gap open rate, the gap effective rate and the gap short-circuit rate within the preset period can be calculated, and the target gap can be determined according to the above, the Z-axis servo motion is driven, the gap size is adjusted to meet the target gap, so that the best discharge state is maintained.

[0073] In summary, the system has the function of self-adaptive matching of the set pulse power supply electrical parameters: when setting the pulse power supply to output different pulse peak voltage levels, the system can automatically identify the current selected level and match the corresponding reference voltage; at the same time, when setting the pulse power supply to output different pulse width intervals, the system can perform parallel and synchronous processing of the pulse width control timing, and automatically perform the sampling voltage timing operation during the set pulse width interval. In addition, the optocoupler connection characteristics designed in the embodiments of the present application can effectively transmit digital signals because only high and low level states are processed without involving the linear change interval of analog signals. This connection design ensures that the detection signal can be accurately and correctly transmitted from the high voltage end to the microcontroller at the low voltage end during signal transmission, thereby avoiding the risk of information loss.

[0074] According to the micro-EDM gap state detection system provided in the embodiments of the present application, the pulse peak voltage recognition module generates different pulse peak voltage levels of the micro-EDM energy scene, and outputs a plurality of sampling peak voltages corresponding to the different pulse peak voltage levels of the micro-EDM energy scene. The first comparison result is obtained by comparing the plurality of sampling peak voltages with the preset comparison voltage. The reference voltage is obtained by the comparator real-time calculation module according to the first comparison result, and the second comparison result is obtained by comparing the reference voltage with the sampling peak voltage. The second comparison result is input to the timing signal parallel driving and discrimination module after being processed in the form of high and low levels. The timing signal parallel driving and discrimination module identifies the pulse type of the sampling peak voltage based on the processed second comparison result, and obtains the gap open rate, the gap efficiency and the gap short circuit rate in the preset period based on the identification result, so as to determine the target gap. Thus, the problem that the response of the existing detection technology to the discharge state lags behind, the real-time performance is poor, and part of the discharge information is lost is solved, the accuracy and real-time performance of the detection result are ensured, and the stability and processing quality of the micro-EDM are improved.

[0075] Next, the micro-EDM gap state detection method according to the embodiments of the present application is described with reference to the accompanying drawings.

[0076] Figure 4 is a flowchart of the micro-EDM gap state detection method of an embodiment of the present application.

[0077] As shown in Figure 4 , the micro-EDM gap state detection method uses the micro-EDM gap state detection system shown in Figure 1 the embodiments, and the method includes the following steps:

[0078] In step S401, the pulse peak voltage identification module generates pulse peak voltage levels of different micro-EDM energy scenarios, and outputs a plurality of voltage signals corresponding to the pulse peak voltage levels of the different micro-EDM energy scenarios, and compares the plurality of voltage signals with a preset comparison voltage to obtain a first comparison result.

[0079] In step S402, the comparator real-time calculation module obtains a reference voltage according to the first comparison result, compares the reference voltage with a sampling peak voltage to obtain a second comparison result, and inputs the second comparison result in the form of high and low levels to the timing signal parallel driving and discrimination module after electrical isolation processing.

[0080] In step S403, the timing signal parallel driving and discrimination module identifies the pulse type of the sampling peak voltage based on the processed second comparison result, and obtains the gap open circuit rate, the gap effective rate and the gap short circuit rate in a preset period based on the identification result, so as to determine the target gap according to the gap open circuit rate, the gap effective rate and the gap short circuit rate.

[0081] It should be noted that the foregoing explanation and description of the micro-EDM gap state detection system also apply to the micro-EDM gap state detection method of this embodiment, which will not be described here.

[0082] Further, in some embodiments, identifying the pulse type of the sampling peak voltage based on the processed second comparison result includes: identifying a first voltage set in the sampling peak voltage that is less than or equal to a first reference voltage, and identifying a second voltage set in the sampling peak voltage that is greater than a second reference voltage, and obtaining a duration of the sampling peak voltage that is greater than the second reference voltage, wherein the second reference voltage is greater than the first reference voltage; determining the pulse type of the sampling peak voltage in the first voltage set as a short circuit pulse, and determining the pulse type of the sampling peak voltage in the second voltage set with a duration greater than or equal to a preset duration as an open circuit pulse, and determining the pulse type of the sampling peak voltage in the second voltage set with a duration less than the preset duration as an effective pulse.

[0083] Further, in some embodiments, before identifying the first voltage set in the sampling peak voltage that is less than or equal to the first reference voltage, it further includes: determining a first empirical coefficient, a peak voltage of an idle waveform and a second empirical coefficient; calculating the first reference voltage based on the product of the first empirical coefficient and the peak voltage of the idle waveform, and calculating the second reference voltage based on the product of the second empirical coefficient and the peak voltage of the idle waveform.

[0084] That is, in the preset pulse width and pulse interval duration of the power supply no-load waveform, the sample peak voltage is compared with the first reference voltage, if there is a sample peak voltage less than or equal to the first reference voltage, it is determined that the pulse type of the sample peak voltage less than or equal to the first voltage set of the first reference voltage in the sample peak voltage is short-circuit pulse; when the sample peak voltage is greater than the first reference voltage, it is further judged that in the preset pulse width and pulse interval duration of the power supply no-load waveform, the sample peak voltage greater than the second reference voltage (the second reference voltage is greater than the first reference voltage) is identified, and the duration of the sample peak voltage greater than the second reference voltage is obtained, the pulse type of the sample peak voltage with a duration less than the preset duration in the second voltage set is determined as effective pulse, and the remaining is open-circuit pulse.

[0085] In order to facilitate those skilled in the art to further understand the micro-EDM gap state detection method provided by the embodiments of the present application, the following will be further described in combination with Figure 5 .

[0086] Step S501, set the first reference voltage U ref =S1·E, the experience coefficient S=1 / 2, and E is the peak voltage of the no-load waveform.

[0087] Step S502, in the pulse width t M , judge whether the rising edge height U pp of the gap discharge waveform is greater than the first reference voltage U ref . If yes, execute step S503, otherwise execute step S507.

[0088] Step S503, determine the pulse type as open-circuit pulse or effective pulse, set the experience coefficient S'=7 / 8, and obtain the second reference voltage U ref '.

[0089] Step S504, in the pulse width t M , judge whether the duration of the rising edge height U pp of the gap discharge waveform greater than the second reference voltage U ref ' is less than the preset duration T·t M . If yes, execute step S505, otherwise execute step S506.

[0090] Step S505, determine the pulse type as effective pulse.

[0091] Step S506, determine the pulse type as open-circuit pulse.

[0092] Step S507, determine the pulse type as short-circuit pulse.

[0093] According to the micro-EDM gap state detection method provided by the embodiment of the present application, through the micro-EDM gap state detection system, the problem that the response of the existing detection technology to the discharge state is delayed, the real-time performance is poor, and part of the discharge information is lost is solved, the accuracy and real-time performance of the detection result are ensured, and the stability and processing quality of the micro-EDM are improved.

[0094] In addition, the terms "first", "second", "third", etc. are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0095] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms is not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0096] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and the ordinary skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A micro-EDM gap state detection system, characterized by, The application relates to a micro-EDM (electrical discharge machining) pulse peak voltage identification device, which comprises a pulse peak voltage identification module, a comparator real-time calculation module and a timing signal parallel driving and distinguishing module. The pulse peak voltage identification module is used for generating pulse peak voltage grades of different micro-EDM energy scenes, outputting multiple voltage signals corresponding to the pulse peak voltage grades of the different micro-EDM energy scenes, and comparing the multiple voltage signals with preset comparison voltages respectively to obtain first comparison results. The comparator real-time calculation module is used for obtaining a reference voltage according to the first comparison results, comparing the reference voltage with a sampling peak voltage to obtain second comparison results, and inputting the second comparison results in the form of high and low levels to the timing signal parallel driving and distinguishing module after electrical isolation processing. The timing signal parallel driving and distinguishing module is used for identifying the pulse type of the sampling peak voltage based on the processed second comparison results, obtaining a gap open rate, a gap effective rate and a gap short circuit rate in a preset period based on the identification results, and determining a target gap according to the gap open rate, the gap effective rate and the gap short circuit rate. The pulse peak voltage identification module comprises a pulse peak voltage generation circuit, a voltage dividing resistor and first to N comparators.

2. The micro-EDM gap condition detection system according to claim 1, wherein The pulse peak voltage generation circuit is used for generating pulse peak voltage grades of different micro-EDM energy scenes. The voltage dividing resistor is used for outputting multiple voltage signals corresponding to the pulse peak voltage grades of the different micro-EDM energy scenes. The first to N comparators are used for comparing the multiple voltage signals with the preset comparison voltages respectively to obtain N-1 binary comparison results, and generating the first comparison results according to the N-1 binary comparison results, wherein N is greater than or equal to 2 and is an integer. The comparator real-time calculation module comprises a multiplexer, a nanosecond-level high-speed comparator and a first optoelectronic coupling element.

3. The micro-EDM gap condition detection system according to claim 2, wherein The multiplexer is used for obtaining the reference voltage according to the first comparison results. The nanosecond-level high-speed comparator is used for comparing the reference voltage with the sampling peak voltage to obtain the second comparison results, and inputting the second comparison results in the form of high and low levels to the timing signal parallel driving and distinguishing module after electrical isolation processing through the first optoelectronic coupling element. The timing signal parallel driving and distinguishing module comprises an upper computer, a pulse power microcontroller, a second optoelectronic coupling element and a MOSFET driver.

4. The micro-EDM gap condition detection system according to claim 3, wherein The upper computer is used for setting the pulse width and pulse interval time length of a gap discharge pulse as a preset pulse width and pulse interval time length. The pulse power microcontroller is used for generating a timing signal for controlling the on-off of a MOSFET according to the preset pulse width and pulse interval time length. The second optoelectronic coupling element is used for parallel transmission of the timing signal. The MOSFET driver is used for controlling the MOSFET to be connected for a time interval of gap discharge ion elimination to meet the preset pulse width and pulse interval time length based on the timing signal. ​ A detection circuit microcontroller is configured to identify a pulse type of the sampled peak voltage according to the processed second comparison result within the preset pulse width pulse interval, and obtain an identification result. A PMAC control card is configured to perform real-time cumulative counting according to the identification result, and calculate a gap open circuit rate, a gap effective rate and a gap short circuit rate within the preset period according to the cumulative counting result, so as to determine the target gap according to the gap open circuit rate, the gap effective rate and the gap short circuit rate.

5. The micro-EDM gap condition detection system according to claim 4, wherein The pulse type includes an open circuit pulse, an effective pulse and a short circuit pulse.

6. The micro-EDM gap condition detection system according to claim 5, wherein The preset comparison voltage is obtained from a middle value of adjacent two voltage signals in the plurality of voltage signals.

7. The micro-EDM gap condition detection system according to claim 6, wherein The sampled peak voltage is a rising edge height of a gap discharge waveform.

8. A micro-EDM gap state detection method, the method employing the micro-EDM gap state detection system according to any one of claims 1 to 7, characterized by, The method comprises the following steps: generating pulse peak voltage levels of the different micro-EDM energy scenarios by using the pulse peak voltage identification module, outputting a plurality of voltage signals corresponding to the pulse peak voltage levels of the different micro-EDM energy scenarios, and comparing the plurality of voltage signals with the preset comparison voltage to obtain the first comparison result; obtaining the reference voltage according to the first comparison result by using the comparator real-time calculation module, comparing the reference voltage with the sampled peak voltage to obtain the second comparison result, and inputting the second comparison result in the form of high and low levels to the time sequence signal parallel driving and discrimination module after electrical isolation processing; identifying the pulse type of the sampled peak voltage based on the processed second comparison result by using the time sequence signal parallel driving and discrimination module, and determining the target gap according to the gap open circuit rate, the gap effective rate and the gap short circuit rate within the preset period based on the identification result.

9. The method of claim 8, wherein, The identification of the pulse type of the sampled peak voltage based on the processed second comparison result comprises: identifying a first voltage set in the sampled peak voltage that is less than or equal to a first reference voltage, identifying a second voltage set in the sampled peak voltage that is greater than a second reference voltage, and obtaining a continuous time length of the sampled peak voltage that is greater than the second reference voltage, wherein the second reference voltage is greater than the first reference voltage; determining the pulse type of the sampled peak voltage in the first voltage set as a short circuit pulse, determining the pulse type of the sampled peak voltage in the second voltage set whose continuous time length is greater than or equal to a preset time length as an open circuit pulse, and determining the pulse type of the sampled peak voltage in the second voltage set whose continuous time length is less than the preset time length as an effective pulse.

10. The method of claim 9, wherein, Before identifying the first voltage set in the sampled peak voltage that is less than or equal to the first reference voltage, the method further comprises: determining a first empirical coefficient, a peak voltage of an empty carrier waveform and a second empirical coefficient. The first reference voltage is calculated based on a product of the first empirical coefficient and a peak voltage of the unloaded waveform, and the second reference voltage is calculated based on a product of the second empirical coefficient and the peak voltage of the unloaded waveform.

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