A method for using kurtosis value as a digital trigger source for vibration signals

Abstract

This invention relates to the field of data storage technology, specifically to a method using kurtosis values ​​as a digital trigger source for vibration signals. The method first acquires the operating status of the original vehicle PLC system's temperature and vibration parameters, including idle and full-speed states. When the system is in the idle state, high-frequency sampling of the temperature and vibration parameters of all channels is performed. The parameters are then cross-sorted according to the order of channel first, followed by sampling point, to obtain a cross sequence. Kurtosis calculation is performed on the cross sequence; when the kurtosis exceeds a preset trigger kurtosis, the system's full-speed state is triggered. When the system is in the full-speed state, normal full-speed sampling of the temperature and vibration parameters of each channel is performed to obtain a parameter sequence for each channel. Kurtosis calculation is performed on the parameter sequence; when the kurtosis is lower than a preset low-speed kurtosis, the system's idle state is triggered. This invention can increase the length of records stored cyclically by an order of magnitude without changing the storage device space.

Description

Technical Field

[0001] This invention relates to the field of data storage technology, and more specifically to a method for using kurtosis values ​​as a digital trigger source for vibration signals. Background Technology

[0002] In vibration analysis systems, multi-channel timed data acquisition is typically used, operating 24 / 7. Over time, this leads to a massive accumulation of sampled data. Some data, constrained by industry standards, requires continuous storage. However, continuous timed sampling generates a large amount of invalid data. Frequent acquisition and processing of invalid data also unnecessarily increases system energy consumption. Therefore, an effective triggering mechanism becomes a crucial issue that needs to be addressed.

[0003] Currently, external triggering of the data acquisition device is usually achieved by adding an additional digital or analog sensing device to the digital interface of the frequency converter or the contactor contacts of a key transmission component. However, this can lead to a potential equipment failure problem. For example, if the physical wiring of the key triggering device is faulty, the communication line is broken, or the device ages and fails, the contactor may arc due to frequent switching, making it a vulnerable part that needs to be replaced periodically. This will cause a series of problems such as rewiring of the associated detection device, and the reliability and maintenance cost of the key device used for triggering will become an issue, introducing more hidden dangers or maintenance costs to the existing system. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for using kurtosis value as a digital trigger source for vibration signals. The specific technical solution adopted is as follows: Obtain the temperature and vibration parameters and the operating status of the system in the original vehicle PLC system. The operating status includes: idle state and full speed state. When the system is in the idle state, the temperature and vibration parameters of all channels of the system are sampled at high frequency. The temperature and vibration parameters are cross-arranged in the order of channel first and then sampling point to obtain a cross sequence. The kurtosis of the cross sequence is calculated. When the kurtosis exceeds the preset trigger kurtosis, the full speed state of the system is triggered. When the system is in the full-speed state, the temperature and vibration parameters of each channel are sampled normally at full speed to obtain the parameter sequence of the temperature and vibration parameters of each channel; the kurtosis of the parameter sequence is calculated, and when the kurtosis is lower than the preset low-speed kurtosis, the idle state of the system is triggered.

[0005] Preferably, the length of the crossover sequence is consistent with the length of the parameter sequence during normal full-speed sampling, and any excess portion is truncated.

[0006] Preferably, the preset trigger kurtosis is ±15.

[0007] Preferably, the step of performing kurtosis calculation on the parameter sequence, and triggering the system's idle state when the kurtosis is lower than a preset low-speed kurtosis, includes: If the kurtosis values ​​of the parameter sequences of all channels are lower than the preset low-speed kurtosis, the system will delay for a preset fixed duration and then enter an idle state.

[0008] Preferably, the preset fixed duration is 1 to 5 minutes.

[0009] The embodiments of the present invention have at least the following beneficial effects: The processing method of this invention has a clear principle, and its triggering does not rely on a single device, but rather on a group of sensors. The relevant triggering data is also stored and processed, ensuring a closed-loop and traceable process. Without changing the storage space, the length of records that the system can cyclically store can be increased by an order of magnitude from quarterly or semi-annual records. Attached Figure Description

[0010] 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.

[0011] Figure 1 This is a flowchart illustrating the steps of a method for using kurtosis value as a digital trigger source for vibration signals, as provided in an embodiment of the present invention. Detailed Implementation

[0012] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method for using kurtosis values ​​as a digital trigger source for vibration signals according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0014] This invention provides a specific implementation method for using kurtosis values ​​as a digital trigger source for vibration signals, applicable to adaptive triggering scenarios. To address the problems of equipment aging and increased maintenance costs associated with external triggering of data acquisition devices using existing methods that rely on the digital interface of frequency converters or contactor contacts in critical transmission components, this invention proposes a method for determining operating conditions using existing vibration sensor arrays without relying on any triggering device. Effective data acquisition is only performed when condition monitoring is required, while ensuring high availability of the triggering logic at the source, as it depends on the sampling device itself, not a single component.

[0015] The following describes in detail, with reference to the accompanying drawings, a specific scheme of the method provided by the present invention that uses kurtosis value as a digital trigger source for vibration signals.

[0016] Please see Figure 1 The diagram illustrates a flowchart of a method for using kurtosis value as a digital trigger source for vibration signals according to an embodiment of the present invention. The method includes the following steps: Step S100: Obtain the temperature and vibration parameters and the operating status of the system in the original vehicle PLC system. The operating status includes: idle state and full speed state.

[0017] The system collects operating condition data from the original vehicle PLC system, which represents the system's operating status. In this embodiment, the data collection frequency is one frame every 5 seconds. During acceptance testing, more operating condition data can be collected, with the total data volume not exceeding 2Kbytes / frame.

[0018] After the system is powered on, it is in an idle state by default. The operating states of the monitoring system include at least two conditions: idle state and full-speed state.

[0019] Temperature and vibration data are collected from the original vehicle PLC system. This data includes vibration data, temperature data, spectrum calculation data, envelope spectrum data, and measured values. In this embodiment, the data collection frequency is 10 seconds per group. Each group contains 30 channels, and the data transmission volume per sample for each channel is 13 Kbytes / frame; the total data volume per sample is 13 × 30 = 400 Kbytes / frame.

[0020] Structural data such as pressure, deflection, and attitude are collected from the original vehicle PLC system. This type of data has a relatively small volume. In this embodiment of the invention, the sampling frequency is one frame every 15 seconds, with each frame not exceeding 1 KB.

[0021] Based on a 60-second interval, the normalized raw sampling data and subsequent processing data generate a data flow rate of: 2K×60 / 5+400K×60 / 10+1K×60 / 15=2428KB / min; that is, the total daily data volume can reach: 2428×24×60=3.4G≤3.5G; according to the existing requirements, the total data volume for 180 days can reach approximately: 180×3.5=650G.

[0022] However, considering the effective operating time of the device, the amount of data that is actually useful for temperature and vibration analysis is less than 1 / 10. In fact, in order to highlight the effective data during display, an additional data cleaning process is required.

[0023] Therefore, both the special equipment as a whole and the motor operate intermittently. Thus, introducing appropriate and reasonable triggering methods can significantly reduce the accumulation of invalid data, improve the overall system analysis, and even enhance the efficiency of historical data retrieval.

[0024] When processing multi-channel vibration signal acquisition, a change to a new hardware acquisition device led to anomalies in waveforms and vibration time-domain indicators during debugging. It appeared that other data had been mixed into the normal channel data, with particularly abnormal kurtosis values ​​reflecting the signal's impact effect and deviation from white noise. For example, even slight movements caused a sharp increase in kurtosis values ​​across all channels. After ruling out faulty channel data mixing, it was realized that this initially erroneous data could be used as a highly effective trigger source. Based on this concept, the acquisition process was optimized and implemented using this invention.

[0025] Step S200: When the system is in the idle state, the temperature and vibration parameters of all channels of the system are sampled at high frequency. The temperature and vibration parameters are cross-arranged in the order of channel first and sampling point second to obtain a cross sequence. The kurtosis of the cross sequence is calculated. When the kurtosis exceeds the preset trigger kurtosis, the full speed state of the system is triggered.

[0026] Data acquisition and processing when the system is in the idle state: Temperature and vibration parameters for all channels are collected and arranged in a one-dimensional array, prioritizing channels over sampling points. This is achieved by cross-arranging the temperature and vibration parameters in the order of channels first, then sampling points. For example, for a three-channel system, the cross-arrangement is: [ch1.sa1,ch2.sa1,ch3.sa1,…,ch1.sa2,ch2.sa2,ch3.sa2,…,ch1.saX,ch2.SaX,ch3.SaX], where ch1.sa1 is the first original sampling point of channel 1, ch2.sa1 is the first original sampling point of channel 2, ch3.sa1 is the first original sampling point of channel 3, ch1.sa2 is the second original sampling point of channel 1, ch2.sa2 is the second original sampling point of channel 2, ch3.sa2 is the second original sampling point of channel 3, ch1.saX is the Xth original sampling point of channel 1, ch2.SaX is the Xth original sampling point of channel 2, and ch3.SaX is the Xth original sampling point of channel 3. It should be noted that the temperature and vibration parameters in the cross sequence are all normalized data.

[0027] The sampling rate in idle mode is moderately increased compared to the full-speed sampling rate, meaning that temperature and vibration parameters of all channels in the system are sampled at a higher frequency. For example, the sampling rate can be increased to twice the speed. The purpose of high-frequency sampling is to improve the sensing efficiency of effective data; even higher sampling frequencies are possible because the number of data points from all channels in a single acquisition is not large.

[0028] The last frame of data is persistently saved only when the set full-speed acquisition cycle arrives. For other sampling data with higher frequencies, only acquisition and processing are performed, but not stored, because they are invalid data. Idle sampling data is written to a special trigger channel when it is stored in the database.

[0029] The length of the sampled data can be the same as the length of the sampled data during normal full-speed sampling, and any excess data will be truncated. This can also be understood as the length of the crossover sequence being the same as the length of the parameter sequence during normal full-speed sampling, with any excess data being truncated.

[0030] The kurtosis of the crossover sequence is calculated. When the kurtosis exceeds the preset trigger kurtosis, the full-speed state of the system is triggered. The kurtosis of the cross sequence formed by this single data acquisition is calculated. When the kurtosis value exceeds the preset trigger kurtosis, the system is triggered to full-speed mode, and full-speed sampling begins immediately. The preset trigger kurtosis is determined through long-term observation and analysis of kurtosis value data. In this embodiment of the invention, the preset trigger kurtosis value is ±15.

[0031] Cross-storing data from different channels is intended to artificially increase kurtosis. During normal operation, the transmission components at various installation locations often operate in tandem. Furthermore, the raw sampled data from each channel inherently exhibits differences in amplitude, phase, and even frequency vibration characteristics due to their different installation locations. Intentionally dispersing the vibration data increases the kurtosis value. When one component is operating while another is not, the kurtosis value remains consistently high. It functions essentially as a digital kurtosis amplifier.

[0032] When triggering full-speed mode, the kurtosis value used needs to be set with a large and a small hysteresis to avoid frequent switching of operating conditions due to the jitter of the digital quantity itself. In this embodiment of the invention, the hysteresis can be set to half of the trigger kurtosis value. The inactive signal is approximately a random signal with a normal distribution and extremely low kurtosis value, less than 1.

[0033] Step S300: When the system is in the full-speed state, the temperature and vibration parameters of each channel are sampled normally at full speed to obtain the parameter sequence of the temperature and vibration parameters of each channel; the kurtosis of the parameter sequence is calculated, and when the kurtosis is lower than the preset low-speed kurtosis, the idle state of the system is triggered.

[0034] Following the original logic, multi-channel temperature and vibration parameters are collected and stored, which means collecting and storing vibration signals and related signals.

[0035] The temperature and vibration parameters of each channel are sampled at full speed to obtain a parameter sequence for each channel. Kurtosis is calculated from the parameter sequence. When the kurtosis is lower than a preset low-speed kurtosis (Low1), the system enters an idle state. If the kurtosis values ​​of all channel parameter sequences are lower than the preset low-speed kurtosis, the system enters an idle state after a preset fixed delay. In this embodiment, the preset fixed delay ranges from 1 to 5 minutes and can be selected by the implementer based on actual conditions. The value of the preset low-speed kurtosis is determined by the implementer through analysis of a large number of kurtosis values.

[0036] It should be noted that channels triggered by parameter numbers can be manually or automatically filtered among all existing acquisition channels in the system, which may block certain specific channels from being tracked.

[0037] It should be noted that extending the preset fixed duration when exiting full-speed mode is not only to avoid collecting data on vibrations in the relevant operating conditions, but also because the displacement of the trolley and crane often occurs before the most critical lifting operation during normal operation of the transmission mechanism. Appropriately delaying the exit allows for a higher probability of capturing more complete transient vibration signals from each transmission subsystem during startup and shutdown, providing effective data support for higher-order random vibration signal analysis. The multi-channel aliased data used for triggering still needs to be stored in the database, as it is essential and forms part of the evidence chain for retrospective analysis. This type of data must be retained and can serve as a basis for later verification of the effectiveness of the triggering operation.

[0038] When exiting full-speed mode, special attention should be paid to adding user shielding or automatically handling non-fixed low-speed kurtosis (Low1) for ease of use on-site. It should be noted that in reality, situations may arise where a channel's vibration exceeds limits, but work cannot be stopped. After manual intervention, it may be found that the vibration level is unlikely to worsen in the short term, leading to a switch to relative vibration trend tracking.

[0039] The processing method of this invention has a clear principle, and its triggering does not rely on a single device, but rather on a group of sensors. The relevant triggering data is also stored and processed, and the process is closed-loop and traceable. Without changing the storage space, the system can increase the length of records stored cyclically from quarterly or semi-annually by an order of magnitude, far exceeding the minimum data storage and traceability standards for recording devices stipulated by national standards. This invention is a general-purpose technology, not only applicable to vibration data processing, but also to the digital automatic triggering of other data. Using kurtosis values ​​as triggers is relatively ideal, but other time-frequency digital indicators are also possible.

[0040] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0041] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for using kurtosis value as a digital trigger source for vibration signals, characterized in that, The method includes the following steps: Obtain the temperature and vibration parameters and the operating status of the system in the original vehicle PLC system. The operating status includes: idle state and full speed state. When the system is in the idle state, the temperature and vibration parameters of all channels of the system are sampled at high frequency. The temperature and vibration parameters are cross-arranged in the order of channel first and then sampling point to obtain a cross sequence. The kurtosis of the cross sequence is calculated. When the kurtosis exceeds the preset trigger kurtosis, the full speed state of the system is triggered. When the system is in the full-speed state, the temperature and vibration parameters of each channel are sampled normally at full speed to obtain the parameter sequence of the temperature and vibration parameters of each channel; the kurtosis of the parameter sequence is calculated, and when the kurtosis is lower than the preset low-speed kurtosis, the idle state of the system is triggered.

2. The method for using kurtosis value as a digital trigger source for vibration signals according to claim 1, characterized in that, The length of the crossover sequence is consistent with the length of the parameter sequence during normal full-speed sampling, and any excess portion is truncated.

3. The method for using kurtosis value as a digital trigger source for vibration signals according to claim 1, characterized in that, The preset trigger kurtosis is ±15.

4. The method for using kurtosis value as a digital trigger source for vibration signals according to claim 1, characterized in that, The step of performing kurtosis calculation on the parameter sequence, and triggering the system's idle state when the kurtosis is lower than a preset low-speed kurtosis, includes: If the kurtosis values ​​of the parameter sequences of all channels are lower than the preset low-speed kurtosis, the system will delay for a preset fixed duration and then enter an idle state.

5. The method for using kurtosis value as a digital trigger source for vibration signals according to claim 4, characterized in that, The preset fixed duration is 1 to 5 minutes.

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