A real-time monitoring method and device for a numerical control system based on a configuration computer

Abstract

The present application relates to the technical field of control system, and particularly relates to a numerical control system real-time monitoring method and device based on a configuration computer, in a tapping process, if a sampling action is triggered, a main shaft load sequence corresponding to a current tapping cycle is acquired; the main shaft load sequence is decoupled to acquire a transmission baseline load sequence for representing mechanical transmission and a cutting fluctuation load sequence for representing a cutting state; a cutting impedance deviation value is determined based on the cutting fluctuation load sequence, and a transmission baseline deviation value is determined based on the transmission baseline load sequence, the cutting impedance deviation value is used to reflect microscopic geometric change characteristics caused by a cutting edge collapse, and the transmission baseline deviation value is used to reflect overall amplitude change characteristics caused by macroscopic mechanical state changes; based on the cutting impedance deviation value and the transmission baseline deviation value, abnormality is judged and early warning is performed. The present application decouples the main shaft load sequence, effectively improving the accuracy of abnormality judgment and early warning.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, specifically to a real-time monitoring method and device for numerical control systems based on a configuration computer. Background Technology

[0002] Rigid tapping is a critical process in the manufacturing of precision electronic structural components and automotive powertrains, requiring a strict synchronization between the spindle rotation and Z-axis feed of a CNC machine tool. However, in the machining of micro-diameter threads, the cutting resistance generated by the micro-diameter tap is extremely small and exhibits high-frequency, low-amplitude characteristics. This resistance is easily masked by the huge inertial torque generated during the start-up, shutdown, and reversal of the spindle motor, as well as the frictional resistance of the guide rail system, resulting in a low signal-to-noise ratio for the effective signal.

[0003] Existing monitoring methods mostly employ the approach of setting a single current threshold. However, when a CNC system executes different feed rates or high-speed reverse movements, the dynamic following error of the servo position loop causes nonlinear scaling and phase shifts in the actual load waveform along the time axis and phase. To avoid false alarms caused by waveform misalignment, engineering practice often forces the relaxation of alarm thresholds. This directly reduces the system's sensitivity to detecting minor chipping or early tool breakage, making it difficult to meet the stringent requirements of precision manufacturing processes for full inspection of machining conditions. Summary of the Invention

[0004] To address the technical problem of low sensitivity in detecting minor chipping or early tool breakage faults in the aforementioned systems, the present invention aims to provide a real-time monitoring method and device for CNC systems based on a configuration computer. The specific technical solution adopted is as follows:

[0005] In a first aspect, the present invention provides a real-time monitoring method for a numerical control system based on a configuration computer, comprising the following steps:

[0006] During the tapping process, if a sampling action is triggered, the spindle load sequence corresponding to the current tapping cycle is obtained;

[0007] The spindle load sequence is decoupled to obtain a transmission baseline load sequence characterizing the mechanical transmission and a cutting fluctuation load sequence characterizing the cutting state.

[0008] The cutting impedance deviation value is determined based on the cutting fluctuation load sequence, and the transmission baseline deviation value is determined based on the transmission baseline load sequence. The cutting impedance deviation value is used to reflect the micro-geometric change characteristics caused by the chipping of the cutting edge, and the transmission baseline deviation value is used to reflect the overall amplitude change characteristics caused by the macro-mechanical state change.

[0009] Based on the cutting impedance deviation value and the transmission baseline deviation value, anomaly judgment and early warning are performed.

[0010] In conjunction with the first aspect described above, in some possible implementations, the method further includes determining whether a sampling action is triggered, wherein determining whether a sampling action is triggered includes:

[0011] During the tapping process, the current Z-axis position is compared with the previous Z-axis position to determine the change in Z-axis feed displacement;

[0012] When the change in Z-axis feed displacement is greater than the set displacement trigger threshold, a sampling action is triggered.

[0013] In conjunction with the first aspect above, in some possible implementations, before decoupling the spindle load sequence, the method further includes:

[0014] The standard sequence length is determined based on the theoretical value of the machining hole depth and the set displacement trigger threshold.

[0015] The spindle load sequence is subjected to fixed-length processing to obtain a processed spindle load sequence, the length of which is equal to the length of the standard sequence.

[0016] In conjunction with the first aspect above, in some possible implementations, the spindle load sequence is subjected to fixed-length processing to obtain a processed spindle load sequence, including:

[0017] For each load value in the processed spindle load sequence, determine the reference index of the target index in the spindle load sequence;

[0018] Based on the load value corresponding to the reference index in the spindle load sequence, determine each load value in the processed spindle load sequence.

[0019] In conjunction with the first aspect above, in some possible implementations, after performing fixed-length processing on the spindle load sequence to obtain the processed spindle load sequence, the method further includes: determining the storage state of the reference spindle load sequence; if the storage state is empty or marked as reset, it is determined that the current stage is initialization, and the obtained processed spindle load sequence is used as the reference spindle load sequence and stored without further decoupling processing of the processed spindle load sequence; if the storage state exists and is marked as valid, the corresponding reference spindle load sequence is obtained.

[0020] In conjunction with the first aspect above, in some possible implementations, the spindle load sequence is decoupled to obtain a transmission baseline load sequence characterizing the mechanical transmission and a cutting fluctuation load sequence characterizing the cutting state, including:

[0021] Determine the number of sampling points per lead based on the currently used tap lead and the set displacement trigger threshold.

[0022] The sliding window radius is determined based on the number of sampling points per single lead;

[0023] Based on the sliding window radius, the spindle load sequence is subjected to moving average filtering to obtain the transmission baseline load sequence;

[0024] A point-by-point difference operation is performed on the spindle load sequence and the transmission baseline load sequence to obtain the cutting fluctuation load sequence.

[0025] In conjunction with the first aspect above, in some possible implementations, determining the cutting impedance deviation value based on the cutting fluctuation load sequence and determining the transmission baseline deviation value based on the transmission baseline load sequence includes:

[0026] The reference transmission baseline load sequence and the reference cutting fluctuation load sequence are obtained after decoupling the reference spindle load sequence;

[0027] The normalized minimum cumulative distance between the cutting fluctuation load sequence and the reference cutting fluctuation load sequence is calculated using the constrained dynamic time warping algorithm to obtain the cutting impedance deviation value.

[0028] The transmission baseline load sequence and the reference transmission baseline load sequence are compared point by point to obtain the transmission baseline deviation value.

[0029] In conjunction with the first aspect above, in some possible implementations, anomaly judgment and early warning are performed based on the cutting impedance deviation value and the transmission baseline deviation value, including:

[0030] If the cutting impedance deviation value is greater than the preset cutting abnormality judgment threshold, the current workpiece state is determined to be a tool abnormality, a feed hold command is sent, and a stop alarm is triggered.

[0031] If the transmission baseline deviation value is greater than the preset transmission abnormality judgment threshold, the current workpiece status is determined to be a transmission abnormality, a maintenance warning signal is sent, and a prompt is made to check the lubrication system.

[0032] If the cutting impedance deviation value is less than or equal to the preset cutting abnormality judgment threshold, and the transmission baseline deviation value is less than or equal to the preset transmission abnormality judgment threshold, then the current workpiece status is determined to be normal processing.

[0033] In conjunction with the first aspect described above, in some possible implementations, the method further includes:

[0034] When the anomaly detection determines that the current workpiece status is normal, the spindle load sequence and the reference spindle load sequence are weighted and fused to update the reference spindle load sequence.

[0035] Secondly, the present invention also provides a real-time monitoring device for a CNC system based on a configuration computer, including a memory and a processor. The memory is used to store executable computer program code, and the processor is used to call and run the executable computer program code from the memory, so that the system executes a real-time monitoring method for a CNC system based on a configuration computer, as described in the first aspect or any possible implementation thereof.

[0036] Thirdly, the present invention also provides a computer program product comprising: computer program code, which, when run on a computer, causes the computer to execute a real-time monitoring method for a numerical control system based on a configuration computer, as described in the first aspect or any possible implementation thereof.

[0037] Fourthly, the present invention also provides a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform a real-time monitoring method for a numerical control system based on a configuration computer, as described in the first aspect or any possible implementation thereof.

[0038] The present invention has the following beneficial effects: If a sampling action is triggered, the spindle load sequence corresponding to the current tapping cycle is obtained. The spindle load sequence is decoupled to obtain the transmission baseline load sequence for characterizing mechanical transmission and the cutting fluctuation load sequence for characterizing cutting state. This physically separates the weak cutting signal from the strong mechanical transmission (friction / inertia) background noise, enabling the system to independently monitor the masked high-frequency cutting features, thus solving the problem of difficulty in extracting fault signals in small-diameter tapping. The cutting impedance deviation value is determined based on the cutting fluctuation load sequence, and the transmission baseline deviation value is determined based on the transmission baseline load sequence. Therefore, based on the macroscopic feature of the cutting impedance deviation value and the microscopic feature of the transmission baseline deviation value, anomaly judgment and early warning are performed, effectively improving the accuracy of monitoring. Attached Figure Description

[0039] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart illustrating the steps of a real-time monitoring method for a numerical control system based on a configuration computer, according to an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of the structure of a real-time monitoring device for a numerical control system based on a configuration computer, according to an embodiment of the present invention. Detailed Implementation

[0042] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0043] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0044] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0045] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0046] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0047] Although operations or steps are described in a specific order in the accompanying drawings in the embodiments of the present invention, this should not be construed as requiring these operations or steps to be performed in the specific order or serial order shown, or requiring all of the shown operations or steps to be performed to obtain the desired result. In the embodiments of the present invention, these operations or steps may be performed serially; they may be performed in parallel; or a portion of these operations or steps may be performed.

[0048] Meanwhile, it is understood that the data involved in the technical solutions of this invention (including but not limited to the data itself, the acquisition or use of the data) shall comply with the requirements of relevant laws, regulations and related provisions. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by those skilled in the art to which this invention pertains. Furthermore, in all division and logarithmic operations involved in this invention, a protection mechanism is employed to prevent computational crashes or invalid values ​​due to a zero denominator or zero input. The implementation of this protection mechanism can be reasonably set according to the actual situation. For example, when the denominator term of a division operation or the argument term of a logarithmic function is zero, a protection parameter with the same dimension as or dimensionless as the denominator term or the argument term can be added. The value of this protection parameter can be a very small value greater than zero, thereby ensuring the robustness and feasibility of the algorithm under extreme conditions. In addition, the normalization function mentioned in this invention, unless otherwise specifically stated, uses maximum-minimum value normalization to normalize the normalization result to the [0, 1] interval or other continuous intervals. The maximum and minimum values ​​used in the maximum-minimum normalization can be obtained according to the actual situation. For example, when multiple values ​​can be obtained in the implementation process and it is necessary to compare the relationship between different values, multiple values ​​can be counted to obtain the maximum and minimum values. However, when only a single value can be obtained in the implementation process, the maximum and minimum values ​​can be obtained by counting based on a large amount of historical experimental data or prior data obtained in the early stage.

[0049] The following will describe in detail, with reference to the accompanying drawings, a real-time monitoring method and device for a numerical control system based on a configuration computer provided by an embodiment of the present invention.

[0050] Figure 1 This diagram illustrates the basic flowchart of a real-time monitoring method for a numerical control system based on a configuration computer, as provided in an embodiment of the present invention. Figure 1 As shown, the method specifically includes the following steps:

[0051] Step S100: If a sampling action is triggered during the tapping process, the spindle load sequence corresponding to the current tapping cycle is obtained.

[0052] During the tapping process, if a sampling action is triggered, it indicates a significant increase in the Z-axis displacement. The system then acquires the load in real time during the current tapping cycle, obtaining a spindle load sequence corresponding to the end of the current tapping cycle. Subsequent data analysis of the spindle load sequence enables accurate anomaly detection and early warning.

[0053] In a specific example, the monitoring system works collaboratively with a configuration computer and edge computing nodes. The edge computing nodes are responsible for real-time data acquisition and caching, while the configuration computer handles the analysis of complex data and monitoring logic to monitor and issue early warnings for anomalies in the tapping process. To achieve this, the monitoring system initializes a spindle load queue in local memory. If a sampling action is triggered, the system synchronously reads the torque current value of the spindle servo drive and appends it to the [database / system]. This results in an updated spindle load queue at the end. This refers to the initial spindle load sequence. Due to mechanical vibrations, servo following errors, and the discreteness of the sampling period during actual machine tool operation, the final obtained sequence... Total number of data points included It often exhibits slight fluctuations around the preset standard length, and different processing batches... The values ​​are all different, and the result is... In essence, it is an unaligned, non-equal-length spindle load queue.

[0054] In one possible implementation, the method further includes determining whether a sampling action is triggered. This determination includes: during the tapping process, comparing the current Z-axis position with the previous Z-axis position to determine the change in Z-axis feed displacement; and determining that a sampling action is triggered when the change in Z-axis feed displacement is greater than a set displacement trigger threshold.

[0055] In a specific example, during the tapping process, the edge computing node monitors the absolute position of the Z-axis servo motor in real time using the feedback from the grating ruler or encoder as the current Z-axis position. And calculate the current Z-axis position in real time. Position relative to the previous axis The absolute difference between them yields the change in Z-axis feed displacement. The change in Z-axis feed displacement. With the set displacement trigger threshold The displacement trigger threshold is compared. The minimum granularity of spatial sampling is defined, for example, set to 0.05 mm, if and only if a change in Z-axis feed displacement is detected. Greater than or equal to the preset displacement trigger threshold (Right now When a sampling action is triggered (i.e., when a certain condition is met), the system will initiate a sampling action; otherwise, the system will not initiate a sampling action. After that, use the current Z-axis position. For the previous Z-axis position If an update is performed but no sampling action is triggered, the previous Z-axis position is maintained. constant.

[0056] Based on the above technical solution, by identifying the change in Z-axis feed displacement during the tapping process, it is possible to accurately determine whether a sampling action has been triggered, effectively reducing the sampling frequency, preventing the generation of a large amount of invalid redundant data in the quasi-static process, and improving the efficiency of subsequent data processing.

[0057] Step S200: Decouple the spindle load sequence to obtain the transmission baseline load sequence for characterizing the mechanical transmission and the cutting fluctuation load sequence for characterizing the cutting state.

[0058] Since one rotation of the spindle corresponds to one pitch lead in the Z-axis feed, the inertial and frictional loads of the spindle motor exhibit low-frequency components that vary with the rotational speed profile, while the cutting impedance generated by the tap's cutting edge penetrating the material exhibits high-frequency components whose period strictly corresponds to a single rotation. Therefore, the obtained spindle load sequence is decoupled to physically separate the inertial load and the cutting load, resulting in a transmission baseline load sequence characterizing the mechanical transmission and a cutting fluctuation load sequence characterizing the cutting state.

[0059] Since the decoupling and difference analysis of spindle load sequence features rely on a strict point-to-point correspondence, the unaligned non-equal length spindle load queues obtained above cannot be directly used in the calculation. They need to be pre-processed to obtain a standard sequence with a length equal to the standard length.

[0060] In one possible implementation, the method further includes, before decoupling the spindle load sequence:

[0061] Step S201: Determine the standard sequence length based on the theoretical value of the machining hole depth and the set displacement trigger threshold.

[0062] Based on the theoretical value of the machining hole depth and the displacement trigger threshold, a fixed standard sequence length is set. The standard sequence length As a globally unified data dimension benchmark, it ensures that the vector length of all subsequent algorithm processing remains constant. Specifically, the theoretical value of the machining hole depth should be the total theoretical Z-axis travel including both the feed and retraction processes.

[0063] In a specific example, the configuration computer calculates the theoretical value of the machining hole depth and the displacement trigger threshold. The ratio of the two values ​​is used as the standard sequence length. For example, for a machining process with a theoretical travel of 50 mm including both feed and retraction, if the set displacement trigger threshold... If the value is 0.05 mm, then the standard sequence length is set. The value is 1000 points.

[0064] Step S202: Perform fixed-length processing on the spindle load sequence to obtain the processed spindle load sequence. The length of the processed spindle load sequence is equal to the length of the standard sequence.

[0065] Based on the standard sequence length obtained above For the initial spindle load sequence Perform fixed-length processing (such as spatial resampling) to obtain a sequence with a length equal to the standard sequence length. Processed spindle load sequence .

[0066] In one possible implementation, the spindle load sequence is processed to obtain a processed spindle load sequence, including: determining a reference index in the spindle load sequence for the target index of each load value in the processed spindle load sequence; and determining each load value in the processed spindle load sequence based on the load value corresponding to the reference index in the spindle load sequence.

[0067] In a specific example, for the processed spindle load sequence The target index corresponding to each load value in the table. , The numerical calculation process is as follows:

[0068] First, index the target Mapped to spindle load sequence In the middle, calculate the corresponding floating-point index. ;in, spindle load queue The total number of actual data points in the data.

[0069] Next, determine the floating-point index. The adjacent integer indices, i.e., the index for obtaining the floor function. and the floor index , This is the floor function. The function is for rounding up and rounding down. and floor index This constitutes the target index. In spindle load sequence The reference index is used. Simultaneously, the interpolation weights are calculated. .

[0070] Finally, based on the reference index, i.e., the floor index. and floor index and interpolation weights Calculated spindle load sequence In the target index Value at position . Among them, when is smaller, it indicates that the distance to the floor index is closer, and the distance to the ceiling index is farther. At this time, a larger weight should be assigned to the floor index , and a smaller weight should be assigned to the ceiling index .

[0071] Based on the above scheme, by performing a fixed-length processing on the main spindle load sequence, a processed main spindle load sequence with a strictly standard sequence length in dimension can be obtained, converting the monitoring benchmark from an unstable time domain to a fixed spatial domain, so that the form of the load data is no longer affected by the change of the feed speed and the difference in the servo acceleration and deceleration response, ensuring the strict correspondence of the data in different processing batches in terms of geometric position.

[0072] After obtaining the above-mentioned processed main spindle load sequence and before decoupling the processed main spindle load sequence, the monitoring system must establish a reference object for subsequent differential calculation, and this process actually undertakes the self-learning function during the cold start of the system.

[0073] In a possible implementation manner, after performing a fixed-length processing on the main spindle load sequence to obtain a processed main spindle load sequence, the method further includes: judging the storage state of the reference main spindle load sequence. If the storage state is empty or marked as the reset state, it is determined that the current is in the initialization stage, and the obtained processed main spindle load sequence is used as the reference main spindle load sequence and stored, and the processed main spindle load sequence is no longer decoupled; if the storage state is existing and marked as valid, the corresponding reference main spindle load sequence is obtained.

[0074] In a specific example, the edge computing node first checks the storage state of the reference main spindle load sequence in the local memory. If it is detected that the storage state of the reference main spindle load sequence is empty, that is, the reference main spindle load sequence is not stored (for example, when the device is powered on and run for the first time) or marked as the reset state (such as marked as the reset state by the technician), the system determines that the current is in the initialization stage. At this time, the system directly copies and stores the processed main spindle load sequence obtained through the above steps in full amount as the reference main spindle load sequence . Subsequently, the system no longer executes the subsequent feature calculation and determination, and directly ends the current monitoring loop. This mechanism ensures that the system can automatically establish a monitoring benchmark in the first processing loop without offline training. It should be understood that during the system initialization stage (without a benchmark), it is default to be in the controlled trial cutting mode or it is required to manually confirm that the first workpiece is qualified to ensure the initial benchmark The effectiveness.

[0075] If a reference spindle load sequence is detected The storage status is "existing", meaning the reference spindle load sequence has already been stored. And once marked as valid, the system reads the reference spindle load sequence. And used as a comparison source for the processed spindle load sequence. The analysis and anomaly detection process. At this point, the processed spindle load sequence... With reference spindle load sequence They all have the same standard sequence length .

[0076] The cutting impedance of rigid tapping with a small diameter is extremely weak, and the signal energy is completely masked by the macroscopic load generated by the spindle motor overcoming the rotor inertia and guide rail friction. Furthermore, the servo drive system has a dynamic following error that varies with speed in high-speed nonlinear motion, which causes the high-frequency signal that can characterize the tool state to slip nonlinearly in spatial phase, making the traditional linear template comparison method ineffective.

[0077] Based on this, after obtaining the reference spindle load sequence, this embodiment decouples the processed spindle load sequence obtained above, physically separating the inertial load and the cutting load to achieve decoupling of mixed information, thereby obtaining the transmission baseline load sequence for characterizing mechanical transmission and the cutting fluctuation load sequence for characterizing cutting state.

[0078] In one possible implementation, the spindle load sequence is decoupled to obtain a transmission baseline load sequence characterizing the mechanical transmission and a cutting fluctuation load sequence characterizing the cutting state, including:

[0079] Step S203: Determine the number of sampling points per lead based on the currently used tap lead and the set displacement trigger threshold.

[0080] The current tap lead and the set displacement trigger threshold are obtained, and the number of sampling points per lead is determined based on the tap lead and the set displacement trigger threshold. Subsequently, a spatial moving average filter is constructed using the number of sampling points per lead to decouple the mixed signal of the processed spindle load sequence obtained above.

[0081] In a specific example, the configuration computer parses the tapping command currently being executed by the CNC system (e.g., G84 cycle) to obtain the lead of the tap currently being used. (Unit: millimeters), the configuration computer is based on this tap lead. and displacement trigger threshold Displacement trigger threshold Much smaller than the tap lead Calculate the number of sampling points per lead. ;in, This represents the rounding function.

[0082] Step S204: Determine the sliding window radius based on the number of sampling points per lead.

[0083] In a specific example, a sliding window radius is defined. The radius of the sliding window The value is the number of single-lead sampling points. The integer value obtained by rounding down to half of the value is the radius of the sliding window. ,in, This is the floor function.

[0084] Step S205: Based on the sliding window radius, perform a moving average filter on the spindle load sequence to obtain the transmission baseline load sequence.

[0085] In a specific example, to ensure the computability of boundary data, the sliding window radius is used as a basis. The spindle load sequence after processing is processed using variable window or truncation methods. A moving average filter is applied to obtain the transmission baseline load sequence. For spindle load sequence Each index , Specifically, these include:

[0086] when At the beginning of the sequence, take the spindle load sequence. In index range Calculate the arithmetic mean of the data within:

[0087]

[0088] when When the sequence is in the middle segment, containing the vast majority of data points, take the spindle load sequence. In index range The data within the window is calculated to be an arithmetic mean. At this point, the window covers the entire single-lead cycle, which can effectively filter out high-frequency cutting components coupled with the rotation cycle.

[0089]

[0090] when At the end of the sequence, take the spindle load sequence. In index range Calculate the arithmetic mean of the data within:

[0091]

[0092] Step S206: Perform point-by-point difference operation on the spindle load sequence and the transmission baseline load sequence to obtain the cutting fluctuation load sequence.

[0093] The transmission baseline load sequence is obtained through the above-mentioned moving average filtering. Then, the spindle load sequence and transmission baseline load sequence By performing point-by-point difference operations, the cutting fluctuation load sequence is obtained. For spindle load sequence and transmission baseline load sequence any index At this time there is .

[0094] Based on the above technical solution, the sliding window radius is reasonably determined by the number of sampling points per lead, and an adaptive moving average filter is applied to the spindle load sequence based on the sliding window radius. This physically separates the weak cutting signal from the strong mechanical transmission (friction / inertia) background noise, enabling the system to independently monitor the masked high-frequency cutting features, thereby solving the problem of difficulty in extracting fault signals in small-diameter tapping.

[0095] Step S300: Determine the cutting impedance deviation value based on the cutting fluctuation load sequence, and determine the transmission baseline deviation value based on the transmission baseline load sequence.

[0096] The cutting fluctuation load sequence obtained by decoupling the spindle load sequence is analyzed. This is compared with the reference transmission baseline load sequence obtained by decoupling the reference spindle load sequence to determine the cutting impedance deviation value. Similarly, the transmission baseline load sequence obtained by decoupling the spindle load sequence is analyzed and compared with the reference transmission baseline load sequence to determine the transmission baseline deviation value. The cutting impedance deviation value reflects the microscopic geometric changes caused by cutting edge chipping, while the transmission baseline deviation value reflects the overall amplitude changes caused by macroscopic mechanical changes such as guideway lubrication and chip entanglement. The cutting impedance deviation value and the transmission baseline deviation value constitute an orthogonal feature set.

[0097] In one possible implementation, the cutting impedance deviation value is determined based on the cutting fluctuation load sequence, including:

[0098] Step S301: Obtain the reference transmission baseline load sequence and the reference cutting fluctuation load sequence after decoupling the reference spindle load sequence.

[0099] According to the above spindle load sequence Decoupling processing is performed, and the transmission baseline load sequence and cutting fluctuation load sequence are obtained in the same way, using the locally stored reference spindle load sequence. Decoupling is performed to obtain the corresponding reference spindle load sequence. Corresponding reference drive baseline load sequence and reference cutting fluctuation load sequence .

[0100] Step S302: Calculate the normalized minimum cumulative distance between the cutting fluctuation load sequence and the reference cutting fluctuation load sequence using the constrained dynamic time warping algorithm to obtain the cutting impedance deviation value.

[0101] Because the servo system exhibits position loop following error during high-speed tapping, the measured cutting peak experiences a nonlinear phase shift in spatial position relative to the reference peak. Directly subtracting the cutting wave load sequence from the reference cutting wave load sequence point-to-point will generate spurious difference signals due to this shift, resulting in inaccurate deviation quantization. Therefore, this embodiment employs a constrained dynamic time warping algorithm to perform differential quantization on the cutting wave load sequence and the reference cutting wave load sequence, thereby obtaining the cutting impedance deviation value.

[0102] In a specific example, the normalized minimum cumulative distance between the cutting undulation load sequence and the reference cutting undulation load sequence is calculated using the constrained dynamic time warping algorithm to obtain the cutting impedance deviation value, including:

[0103] First, construct a cumulative distance matrix. The cumulative distance matrix The dimension is .

[0104] Secondly, to prevent the algorithm from incorrectly matching the waveform of the current thread profile to adjacent profiles, thereby masking the waveform loss caused by tool breakage, the system must impose strict geometric constraints. Therefore, the search radius for the regular path must be set. equal to window radius (That is, the number of points corresponding to half a lead). In calculating the cutting fluctuation load sequence... The data value at index i Compared with the reference cutting fluctuation load sequence The data value at index j When the distance between them, only when Calculations are only performed when conditions are met; otherwise, an infinite penalty value is applied. Specifically, for point pairs that satisfy the constraints... Define local distance .

[0105] Next, based on local distance Determine the cumulative distance matrix The value of the cumulative distance matrix The recursive calculation formula is as follows:

[0106]

[0107] in, This is a function that takes the minimum value.

[0108] Finally, based on the above recursive calculation formula, the cumulative distance matrix is ​​calculated. According to low dimensions To higher dimensions The cumulative distance matrix is ​​calculated and filled by iterating through the traversal order. The values ​​of all cells satisfying the geometric constraints are used to obtain a normalized minimum cumulative distance, which is then used as the cutting resistance deviation value. At this point, we have:

[0109]

[0110] in, The length of the optimal regular path is obtained by counting the number of path nodes using a backtracking method.

[0111] Step S303: Perform a point-by-point difference comparison between the transmission baseline load sequence and the reference transmission baseline load sequence to obtain the transmission baseline deviation value.

[0112] Unlike high-frequency cutting signals, the transmission baseline load sequence primarily reflects the overall friction level and inertial state of the mechanical transmission chain. It is a low-frequency, broadband signal, insensitive to minute phase deviations but highly sensitive to the overall amplitude increase. Therefore, the transmission baseline deviation value is obtained by directly comparing the point-by-point differences between the transmission baseline load sequence and the reference transmission baseline load sequence.

[0113] In a specific example, the measured transmission baseline sequence is calculated. With reference transmission baseline sequence Same index between Value at position and The sum of absolute distances is used to obtain the transmission baseline deviation value. At this time there is .

[0114] Based on the above technical solution, by utilizing the elastic matching characteristics of the dynamic time warping algorithm, the cutting fluctuation load sequence is nonlinearly aligned on the time axis, thereby compensating for the phase lag caused by servo following error. Furthermore, the geometric constraint of half a lead cycle is used to limit the warping range of the matching path, preventing the algorithm from incorrectly matching the waveform distortion caused by cutting edge chipping to adjacent complete waveform cycles. This ensures that the calculated cutting impedance deviation value can accurately reflect the micro-geometric state of the tool, and achieves the interception of minor cutting edge chipping faults without reducing the alarm threshold.

[0115] Step S400: Based on the cutting impedance deviation value and the transmission baseline deviation value, perform anomaly judgment and early warning.

[0116] Based on the determined cutting impedance deviation and transmission baseline deviation values, independent judgments and early warnings are made for the micro-geometry of the tool and the macro-transmission state of the machine tool, respectively, thereby achieving graded interception before extremely minor cutting fault signals are overwhelmed. Simultaneously, a closed-loop feedback mechanism can be used to counteract thermal drift generated during long-term machine tool operation, ensuring the long-term effectiveness of the monitoring benchmark.

[0117] In one possible implementation, anomaly judgment and early warning are performed based on the cutting impedance deviation value and the transmission baseline deviation value, including: if the cutting impedance deviation value is greater than a preset cutting anomaly judgment threshold, the current workpiece state is determined to be a tool anomaly, a feed hold command is sent, and a stop alarm is triggered; if the transmission baseline deviation value is greater than a preset transmission anomaly judgment threshold, the current workpiece state is determined to be a transmission anomaly, a maintenance early warning signal is sent, and a prompt to check the lubrication system is made; if the cutting impedance deviation value is less than or equal to the preset cutting anomaly judgment threshold, and the transmission baseline deviation value is less than or equal to the preset transmission anomaly judgment threshold, the current workpiece state is determined to be normal machining.

[0118] In a specific example, the edge computing node retrieves a preset threshold parameter from local storage and uses the cutting impedance deviation value, which characterizes the integrity of the cutting edge, as an example. and the transmission baseline deviation value characterizing the resistance of the mechanical transmission chain Compare with the preset threshold parameter:

[0119] Based on the tool condition, the system will determine the cutting impedance deviation value. Compared with the preset cutting anomaly judgment threshold Compare. The threshold. The configuration computer uses the cutting resistance deviation values ​​of historical normal machining batches. The distribution is statistically set, for example, to three times the standard deviation of the mean. Since servo phase slip interference has been eliminated through data decoupling, the cutting impedance deviation value... Sensitive only to abrupt changes in waveform shape, thus allowing for lower settings. To intercept minute blade breaks. If The system determines that the current workpiece status is "tool abnormality" and immediately sends a feed hold command to the CNC system, while simultaneously reporting a shutdown alarm to the configuration computer.

[0120] Based on the machine tool's condition, the system will determine the transmission baseline deviation value. Compared with the preset transmission abnormality judgment threshold Compare. The threshold. Used to monitor macroscopic faults such as lubrication failure, guide rail wear, or chip entanglement, the threshold for detecting transmission abnormalities can be determined based on the statistical distribution of transmission baseline deviation values ​​generated during several normal processing cycles at the initial stage of equipment startup. For example, the average and standard deviation of several transmission baseline deviation values ​​can be calculated, and the average value can be added to the standard deviation by a preset multiple and a preset engineering margin constant as the threshold for determining the transmission abnormality. .like The system determines the current workpiece status as "transmission abnormality". Since this type of fault is usually not instantaneously destructive, the system does not interrupt the current processing, but sends a maintenance warning signal to the configuration computer and prompts the operator to check the lubrication system.

[0121] If and only if and When the system determines the current workpiece status as "processing normal", it will proceed to the subsequent baseline update process.

[0122] Based on the above technical solution, by using the cutting impedance deviation value and the transmission baseline deviation value for anomaly judgment and early warning, it is possible to distinguish whether the load change is caused by tool breakage or thermal elongation drift of the machine tool transmission chain, thus solving the problem of systemic false alarms caused by changes in environmental conditions.

[0123] During continuous operation of the machine tool, the temperature of the spindle bearings and ball screws gradually increases, causing changes in the viscosity of the lubricating oil and the preload, which in turn causes a slow physical drift of the load baseline. To prevent false alarms caused by the fixed reference sequence deviating from the actual operating conditions, the system can dynamically correct the reference using measured data deemed normal.

[0124] In one possible implementation, the method further includes: when the current workpiece state is determined to be normal during anomaly detection, performing a weighted fusion of the spindle load sequence and the reference spindle load sequence to update the reference spindle load sequence.

[0125] In a specific example, when the above anomaly detection result indicates normal machining, an update action is triggered to the reference spindle load sequence: the system reads the current normalized spindle load sequence. and the reference spindle load sequence stored locally The updated reference spindle load sequence is calculated using an exponentially weighted moving average algorithm. For the updated reference spindle load sequence Each spatial location in ( ), at this time there is ,in, To adjust the weighting coefficient (for example, a value between 0.01 and 0.05). This coefficient determines the rate at which the reference sequence follows the current change. The smaller the value, the more stable the reference and the stronger its noise resistance; the larger the value, the faster the reference adapts to thermal drift.

[0126] After the calculation is complete, the system will update the results. Overwrite to local memory as a new reference spindle load sequence It serves as a reference for comparison in the next workpiece processing cycle.

[0127] Based on the above technical solution, by introducing an exponentially weighted update mechanism only under normal conditions, the monitoring system can automatically adapt to the thermal equilibrium process of the machine tool, maintain a high signal-to-noise ratio monitoring capability, avoid false alarms caused by fixed thresholds, and improve monitoring accuracy.

[0128] Based on the same inventive concept, embodiments of the present invention also provide a real-time monitoring device for CNC systems based on a configuration computer, such as... Figure 2 As shown, the monitoring device includes: a memory, a processor, and computer program code stored in the memory and running on the processor 802, wherein when the processor executes the computer program code, the system can perform any of the aforementioned real-time monitoring methods for CNC systems based on configuration computers.

[0129] In this embodiment of the invention, the system can be divided into functional modules according to the above method example. For example, each module can correspond to a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0130] Based on the same inventive concept, embodiments of the present invention also provide a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute any of the aforementioned real-time monitoring methods for CNC systems based on configuration computers.

[0131] Based on the same inventive concept, embodiments of the present invention also provide a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform any of the aforementioned real-time monitoring methods for CNC systems based on configuration computers.

[0132] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A real-time monitoring method for a numerical control system based on a configuration computer, characterized in that, Includes the following steps: During the tapping process, if a sampling action is triggered, the spindle load sequence corresponding to the current tapping cycle is obtained; The spindle load sequence is decoupled to obtain a transmission baseline load sequence characterizing the mechanical transmission and a cutting fluctuation load sequence characterizing the cutting state. The cutting impedance deviation value is determined based on the cutting fluctuation load sequence, and the transmission baseline deviation value is determined based on the transmission baseline load sequence. The cutting impedance deviation value is used to reflect the micro-geometric change characteristics caused by the chipping of the cutting edge, and the transmission baseline deviation value is used to reflect the overall amplitude change characteristics caused by the macro-mechanical state change. Based on the cutting impedance deviation value and the transmission baseline deviation value, anomaly judgment and early warning are performed; Determining the cutting impedance deviation value based on the cutting fluctuation load sequence and determining the transmission baseline deviation value based on the transmission baseline load sequence includes: The reference transmission baseline load sequence and the reference cutting fluctuation load sequence are obtained after decoupling the reference spindle load sequence; The normalized minimum cumulative distance between the cutting fluctuation load sequence and the reference cutting fluctuation load sequence is calculated using the constrained dynamic time warping algorithm to obtain the cutting impedance deviation value. The transmission baseline load sequence and the reference transmission baseline load sequence are compared point by point to obtain the transmission baseline deviation value; Based on the cutting impedance deviation value and the transmission baseline deviation value, anomaly judgment and early warning are performed, including: If the cutting impedance deviation value is greater than the preset cutting abnormality judgment threshold, the current workpiece state is determined to be a tool abnormality, a feed hold command is sent, and a stop alarm is triggered. If the transmission baseline deviation value is greater than the preset transmission abnormality judgment threshold, the current workpiece status is determined to be a transmission abnormality, a maintenance warning signal is sent, and a prompt is made to check the lubrication system. If the cutting impedance deviation value is less than or equal to the preset cutting abnormality judgment threshold, and the transmission baseline deviation value is less than or equal to the preset transmission abnormality judgment threshold, then the current workpiece status is determined to be normal processing.

2. The real-time monitoring method for a numerical control system based on a configuration computer according to claim 1, characterized in that, The method further includes determining whether a sampling action is triggered, wherein determining whether a sampling action is triggered includes: During the tapping process, the current Z-axis position is compared with the previous Z-axis position to determine the change in Z-axis feed displacement; When the change in Z-axis feed displacement is greater than the set displacement trigger threshold, a sampling action is triggered.

3. The real-time monitoring method for a numerical control system based on a configuration computer according to claim 1, characterized in that, Before decoupling the spindle load sequence, the method further includes: The standard sequence length is determined based on the theoretical value of the machining hole depth and the set displacement trigger threshold. The spindle load sequence is subjected to fixed-length processing to obtain a processed spindle load sequence, the length of which is equal to the length of the standard sequence.

4. The real-time monitoring method for a numerical control system based on a configuration computer according to claim 3, characterized in that, The spindle load sequence is processed to a fixed length to obtain a processed spindle load sequence, including: For each load value in the processed spindle load sequence, determine the reference index of the target index in the spindle load sequence; Based on the load value corresponding to the reference index in the spindle load sequence, determine each load value in the processed spindle load sequence.

5. The real-time monitoring method for a numerical control system based on a configuration computer according to claim 4, characterized in that, After performing fixed-length processing on the spindle load sequence to obtain the processed spindle load sequence, the method further includes: determining the storage state of the reference spindle load sequence; if the storage state is empty or marked as reset, it is determined that the current stage is initialization, and the obtained processed spindle load sequence is used as the reference spindle load sequence and stored without further decoupling processing of the processed spindle load sequence; if the storage state is existing and marked as valid, the corresponding reference spindle load sequence is obtained.

6. The real-time monitoring method for a numerical control system based on a configuration computer according to claim 1, characterized in that, The spindle load sequence is decoupled to obtain a transmission baseline load sequence characterizing the mechanical transmission and a cutting fluctuation load sequence characterizing the cutting state, including: Determine the number of sampling points per lead based on the currently used tap lead and the set displacement trigger threshold. The sliding window radius is determined based on the number of sampling points per single lead; Based on the sliding window radius, the spindle load sequence is subjected to moving average filtering to obtain the transmission baseline load sequence; A point-by-point difference operation is performed on the spindle load sequence and the transmission baseline load sequence to obtain the cutting fluctuation load sequence.

7. The real-time monitoring method for a numerical control system based on a configuration computer according to claim 1, characterized in that, The method further includes: When the anomaly detection determines that the current workpiece status is normal, the spindle load sequence and the reference spindle load sequence are weighted and fused to update the reference spindle load sequence.

8. A real-time monitoring device for a numerical control system based on a configuration computer, characterized in that, The system includes a memory, a processor, and executable computer program code stored in the memory and executable on the processor. When the processor executes the computer program code, it performs a real-time monitoring method for a numerical control system based on a configuration computer as described in any one of claims 1 to 7.

Images