Vibration monitoring method and system for vehicle-mounted CT scanning unit

Abstract

The invention relates to a vibration monitoring method and system for a vehicle-mounted CT scanning unit. The vibration monitoring method comprises the following steps: 1) collecting three-axis acceleration data of the vehicle-mounted CT scanning unit in real time through a vehicle-mounted vibration sensing device, and carrying out filtering sampling; and 2) performing frequency spectrum calculation on the sampled three-axis acceleration data to obtain a power spectrum density PSD and an RMS value of a corresponding frequency range, and generating a vibration report. Compared with the prior art, the method has the advantages of being real-time, accurate, visual, comprehensive in monitoring, high in expandability and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vibration monitoring, in particular to a vibration monitoring method and system for a vehicle-mounted CT scanning unit. BACKGROUND

[0002] The mobile vehicle-mounted CT medical vehicle is a mobile medical device integrating a CT scanning unit on a special vehicle, mainly applied to epidemic prevention and control, disaster rescue and basic medical service scenes. Through the CT scanning unit, whole-body image diagnosis and special screening are performed, and the dual functions of routine medical resource allocation and emergency response are combined.

[0003] During the operation of the mobile vehicle-mounted CT medical vehicle, it is easily affected by low-frequency (500Hz) vibrations due to environmental factors such as road conditions and working conditions. In addition, there are many uncertainties during operation, such as accidental impact, violent transportation, and extreme road conditions, which may cause structural damage or performance degradation of the vehicle-mounted CT scanning unit. However, there is currently a lack of specific application and practice in monitoring and analyzing the vibration of the mobile vehicle-mounted CT medical vehicle during transportation and use. In the event of damage to the CT scanning unit during transportation, timely alarm, evidence collection and preservation cannot be achieved.

[0004] Therefore, a system is needed that can both collect evidence in a timely manner and monitor and alarm the transportation status of the CT scanning unit, effectively ensuring the safe transportation of the CT scanning unit and improving transportation conditions to provide data support for subsequent damage assessment. SUMMARY

[0005] To solve the technical problems in the background art, the present application provides a vibration monitoring method for a vehicle-mounted CT scanning unit, comprising the following steps:

[0006] 1) Real-time acquisition of three-axis acceleration data of the vehicle-mounted CT scanning unit by a vehicle-mounted vibration sensing device and filtering sampling;

[0007] 2) Frequency spectrum calculation of the sampled three-axis acceleration data to obtain the power spectral density (PSD) and the RMS value of the corresponding frequency range, and generate a vibration report.

[0008] Further, the step 1) specifically comprises the following steps:

[0009] 11) Configuring system parameters according to the actual operation of the mobile vehicle-mounted CT medical vehicle;

[0010] 12) Configuring the communication protocol of the upper computer;

[0011] 13) Real-time acquisition of three-axis acceleration data of the vehicle-mounted CT scanning unit according to the configured system parameters and communication protocol, and filtering sampling.

[0012] Further, the system parameters specifically include system operation related parameters, report output related parameters, system state related parameters and system time related parameters.

[0013] The system operation related parameters include acceleration sensor calibration parameters, frequency domain calculation parameters and alarm related parameters, the acceleration sensor calibration parameters include acceleration sensor magnification and offset, the frequency domain calculation parameters include report period, overlap rate and maximum and minimum values of PSD frequency range for calculating RMS value, the alarm related parameters include RMS alarm threshold, PSD monitoring frequency, PSD alarm threshold, impact time and impact alarm threshold.

[0014] The report output related parameters include set RMS value corresponding to PSD frequency range, PSD value corresponding to each PSD monitoring frequency and impact times exceeding impact alarm threshold.

[0015] Further, in the step 12), the communication protocol adopts master-slave response mode for data communication, and the data format of request frame and response frame of the communication protocol is composed of frame header, command, length, data and check bit, wherein the frame header is used to distinguish master and slave, the command includes reset, read parameter, read measurement data and read report command, and the length is specifically the length of data plus the length of check code.

[0016] Further, the step 2) specifically includes the following steps:

[0017] 21) segment and recombine the collected acceleration data according to sampling frequency of acceleration data and overlap rate;

[0018] 22) multiply the segmented and recombined acceleration data segment by Hanning window for amplitude adjustment;

[0019] 23) perform frequency spectrum calculation by using fast Fourier transform to obtain power spectrum density PSD and RMS value corresponding to frequency range.

[0020] Further, in the step 22), considering that the acceleration data sampled from the acceleration sensor is in unit of g, the formula of Hanning window is:

[0021]

[0022] wherein n represents the n-th sampled acceleration data in the segmented and recombined data segment.

[0023] Further, in step 23), after the fast Fourier transform of the acceleration data segment after the current time segment reorganization, the power spectral density PSD of the current time is obtained, all power spectral densities PSD in the reporting period are continuously obtained, and the average value of the PSD is calculated as the power spectral density PSD in the current reporting period, and the RMS value of the corresponding frequency range is calculated accordingly.

[0024] Further, according to the actual operation of the mobile vehicle-mounted CT medical vehicle, the sampling frequency of the acceleration data is set to 2048Hz, the maximum and minimum values of the PSD frequency range for calculating the RMS value are set to 4Hz and 200Hz respectively, the overlap rate is set to 50%, the number of PSD monitoring frequencies is set to 20, the total number of corresponding PSD alarm thresholds is 60, the maximum analyzable frequency range of the power density curve in the vibration report is 1024Hz, and the resolution is 1Hz.

[0025] Further, when the continuously monitored acceleration values are higher than the set impact alarm threshold, and the duration exceeds the set impact time, it is determined that an impact event occurs, and the number of one-time impacts is recorded in the vibration report, and when the monitored acceleration values are lower than the set impact alarm threshold and last for 1 second, the impact event monitoring is exited, so as to avoid multiple counting of one-time impact events.

[0026] A vibration monitoring system of a vehicle-mounted CT scanning unit, comprising:

[0027] A communication setting module is used to realize the communication parameter setting of the upper computer and the vehicle-mounted vibration sensing device.

[0028] An operation state display module is used to display the system operation state.

[0029] A parameter configuration module is used to realize the configuration of the system parameters.

[0030] A sensor calibration module is used to obtain the calibration value of the acceleration sensor by using two-point linearization calculation based on the original sampling value curve of the acceleration, and is configured with a calibration auxiliary tool.

[0031] A curve control and display module is used to select the type of data curve display, including the real-time measurement curve, the original sampling value curve and the power density curve corresponding to the X, Y and Z three axes.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] The application provides a kind of vibration monitoring method and system of vehicle-mounted CT scanning unit, can be collected, recorded, analysis and storage to the vibration condition under the vehicle transportation condition, real-time, accurate, intuitively monitor the vibration energy and impact event that the to-be-measured vehicle-mounted CT scanning unit is subjected to in the monitoring frequency range, facilitate to realize the transportation condition of vehicle-mounted CT scanning unit and other valuable equipment and goods is monitored and analyzed, facilitate subsequent data support for improving transportation condition is provided, and in the form of edge computing is adopted, without other equipment cooperation, data processing and storage are carried out in front end, effectively save computing resources and overall system overhead, in addition, the application has strong expansibility, can be applicable to the vibration condition monitoring of other various traffic transport tools and the transportation process of vehicle-mounted valuable goods. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 Method flow chart of the vibration monitoring method of vehicle-mounted CT scanning unit of the application;

[0035] Figure 2 System principle architecture diagram of the vibration monitoring system of vehicle-mounted CT scanning unit of the application; DETAILED DESCRIPTION

[0036] The application will be described in detail below in conjunction with the drawings and specific embodiments. The present embodiment is implemented on the premise of the technical scheme of the application, and detailed implementation mode and specific operation process are given, but the protection scope of the application is not limited to the following examples.

[0037] It should be noted that in the present specification, similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0038] In the description of the present embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0039] The terms "first", "second" and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0040] It should be noted that in the description of the embodiments, unless otherwise explicitly specified and limited, the terms "set", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments can be understood according to the specific circumstances.

[0041] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0042] Embodiments

[0043] The present application provides a kind of vibration monitoring method and system of vehicle-mounted CT scanning unit, to move vehicle-mounted CT medical vehicle in CT machine in the process of driving or transportation is subjected to vibration or impact, by real-time acquisition vehicle-mounted CT scanning unit in X, Y, Z three axis vibration data, the power spectral density PSD of three-axis vibration data and the effective value RMS (root mean square) in corresponding frequency range are calculated, and vibration state (vibration frequency and vibration energy) of vehicle-mounted CT scanning unit is analyzed according to this, while according to the preset alarm threshold, vibration and impact event exceeding range are alarmed and recorded.In addition, after monitoring data and measurement time are one-to-one corresponding, it is stored to local, can realize the grasp and monitoring of the health status of vehicle-mounted CT scanning unit, help to realize predictive maintenance, can provide data support for the fault of vehicle-mounted CT scanning unit and other medical equipment to be predicted and diagnosed.

[0044] The vibration monitoring method of vehicle-mounted CT scanning unit provided by the present application is realized on hardware based on vibration monitoring system, which includes vehicle-mounted vibration sensing device arranged on the vehicle-mounted CT scanning unit to be tested for real-time detection of three-axis acceleration of the vehicle-mounted CT scanning unit to be tested, and upper PC or vehicle-mounted controller in communication with the vehicle-mounted vibration sensing device, and the upper PC runs upper computer software for realizing parameter configuration and operation monitoring.

[0045] The vehicle-mounted vibration sensing device is built-in three-axis acceleration sensor, processor and acquisition filtering circuit, the three-axis acceleration sensor is used to detect the three-axis acceleration of the vehicle-mounted CT scanning unit to be tested in real time, to obtain three-axis acceleration raw data, the acquisition filtering circuit filters and denoises the three-axis acceleration raw data, and the processor records and stores the power spectral density PSD and corresponding RMS value obtained by spectrum calculation, generates a vibration monitoring report, and can also communicate data and configure parameters with the upper PC or vehicle-mounted controller.

[0046] AsFigure 1 As shown, the application provides a vibration monitoring method of a vehicle-mounted CT scanning unit, comprising the following steps:

[0047] I. Real-time acquisition of three-axis acceleration data of the vehicle-mounted CT scanning unit;

[0048] 11) Configure system parameters according to the actual operation of the mobile vehicle-mounted CT medical vehicle;

[0049] In this example, the host computer sets the system parameters through the USB debugging interface, and the system parameters include system operation related parameters, report output related parameters, and system state and time related parameters.

[0050] (1) The system operation parameters mainly include acceleration sensor calibration parameters, frequency domain calculation parameters, and alarm related parameters. The acceleration sensor calibration parameters include the acceleration sensor magnification and offset, the frequency domain calculation parameters include the report period (in this example, it is set to 15 minutes, which can also be set according to the actual situation), the overlap rate (in this example, it is set to 50%, which can also be set according to the actual situation), and the maximum and minimum values of the PSD frequency range for calculating the RMS value, and the alarm related parameters include the RMS alarm threshold, the PSD monitoring frequency, the PSD alarm threshold, the impact time, and the impact alarm threshold. It is worth noting that the PSD monitoring frequency and the PSD alarm threshold are set according to the actual operation of the mobile vehicle-mounted CT medical vehicle. In this example, the same N PSD monitoring frequencies are set for the X, Y, and Z axes (in this example, a total of 20 PSD monitoring frequencies are set according to the actual operation of the mobile vehicle-mounted CT medical vehicle, including 1Hz, 2Hz, 4Hz, 6Hz, 25Hz, 40Hz, 90Hz, 100Hz, 200Hz, 500Hz, etc., to improve the discrimination, and in the future, all PSD monitoring frequencies can be covered to achieve more detailed monitoring), and for the PSD alarm threshold, the N PSD monitoring frequencies on the X, Y, and Z axes correspond to their respective PSD alarm thresholds, a total of 3N.

[0051] When the frequency domain calculation parameters and the alarm related parameters are updated, the system will clear all the calculation data in the current report period and start monitoring the current report period again according to the new parameters. For the PSD monitoring frequency and the PSD alarm threshold in the alarm related parameters, the application configures a total of 20 PSD monitoring frequencies and a total of 60 PSD alarm thresholds according to the actual operation of the mobile vehicle-mounted CT medical vehicle. When the current PSD monitoring frequency is configured as 0Hz or the current configured PSD monitoring frequency is greater than the PSD monitoring frequency configured immediately after it, the input value after it is automatically ignored, so that all the configured PSD monitoring frequencies generate a power density curve in a logarithmic coordinate system in the order from small to large.

[0052] (2) The report output related parameters include the RMS value corresponding to the set PSD frequency range, the PSD value corresponding to each PSD monitoring frequency, and the number of impacts exceeding the impact alarm threshold. When each vibration report period arrives, the PSD value corresponding to each PSD monitoring frequency and the RMS value corresponding to the set PSD frequency range will be calculated and output according to the acceleration measurement results in the current vibration report period, and the corresponding alarm state will be output according to the PSD alarm threshold;

[0053] In this example, the sampling rate is configured to be 2048 Hz based on the actual operation of the mobile vehicle-mounted CT medical vehicle. Therefore, after spectrum calculation, the maximum analyzable frequency range is 1024 Hz. Therefore, according to the resolution of 1 Hz, there are a total of 1025 effective monitoring frequency points corresponding to 0-1024 Hz (each PSD monitoring frequency is selected from the 1025 effective monitoring frequency points according to actual requirements).

[0054] (3) The system state related parameters are used to quickly indicate the error location when a system error occurs (such as whether a hardware, external crystal oscillator, and memory error occurs). The system state related parameters mainly include ADC sampling clock, ADC sampling count, battery state identification, memory state identification, etc.

[0055] (4) The system time related parameters are used to realize time calibration of the vibration monitoring system. When time calibration is needed, first stop updating the system time, start receiving newly written time data, corresponding to the year, month, and day data, and then notify the system that the new time has been set. Write the new time into the vibration monitoring system internally to complete the time setting. When the processor is connected to the matching host computer, the host computer will also automatically calibrate the system time.

[0056] 12) Configure the communication protocol of the host computer

[0057] In this example, the host computer software in the upper PC uses a USB communication interface to communicate in a virtual serial port mode, and realizes data interaction based on the set communication protocol.

[0058] The communication protocol uses a master-slave response mode for data communication, in which the vehicle-mounted vibration sensing device is the slave and the host computer client of the upper PC is the master. When the master and slave communicate, the client first initiates, and the data format of the request frame and the response frame is composed of a frame header, a command, a length, data, and a check bit, wherein:

[0059] Frame header (0x53 / 0x52): used to distinguish whether the client or the vehicle-mounted vibration sensing device;

[0060] Command (1 byte): including reset, read parameter, read measurement data, read report, etc.

[0061] Data: Different data corresponding to the command, including three-axis acceleration measurement data, vibration report data, system all parameters, etc.

[0062] Length (2 byte): The length of the data plus the length of the check code.

[0063] Check bit (2 byte): Obtained by operating from the frame header to the last byte of the data bit.

[0064] 13) According to the configured system parameters and communication protocol, the three-axis acceleration data of the vehicle-mounted CT scanning unit is obtained in real time, and is filtered and sampled.

[0065] The three-axis acceleration sensor in the vehicle-mounted vibration sensing device detects the three-axis acceleration of the vehicle-mounted CT scanning unit to be measured in real time, outputs the three-axis acceleration raw data, and the three-axis acceleration raw data is further filtered and denoised by the acquisition filtering circuit and sent to the processor.

[0066] II. The sampled three-axis acceleration data is calculated to obtain the power spectral density PSD and the RMS value of the corresponding frequency range, and a vibration report is generated.

[0067] In this example, the Welch method of the segmented period method + window function + fast Fourier transform calculation is used to calculate the power spectral density PSD. Since the acceleration sampling of the three-axis acceleration sensor is continuous, the sampled data needs to be segmented, then multiplied by the Hanning window, and the convergence on both sides is improved to improve the frequency leakage in the frequency spectrum analysis. Finally, the fast Fourier transform is used for spectrum calculation to obtain the power spectral density PSD and the RMS value of the corresponding frequency range, which is output as part of the vibration report.

[0068] The processor realizes continuous sampling and filtering of the acceleration values of the X, Y, and Z axes of the vehicle-mounted CT scanning unit to be measured through the three-axis acceleration sensor and the acquisition filtering circuit. The sampling frequency is set to 2048 Hz (since the vibration of the mobile vehicle-mounted CT medical vehicle when running is mainly low-frequency vibration below 500 Hz, according to the Shannon sampling theorem and considering the sampling margin, the sampling frequency is preferably set to 2048 Hz), in addition, in order to better fit the actual running situation of the mobile vehicle-mounted CT medical vehicle, the frequency resolution is configured to 1 Hz when performing frequency domain calculation, therefore, it is necessary to perform frequency domain calculation once after every 2048 data is collected.

[0069] In addition, since the resolution of the frequency domain calculation result is 1 Hz, 2048 sample data of the nearest segment are selected for calculation according to the overlap rate of each segment data, in this example, considering the calculation amount and accuracy, the overlap rate is set to 50%, that is, 1024 acceleration data are newly collected every 0.5 seconds, the last 1024 sample data of the current time and the previous time data form a new data segment, so that the current 2048 sample data is subjected to a spectrum operation every 0.5 seconds, and finally the power spectral density PSD of the data segment at all times in the reporting period is accumulated, when the reporting period arrives, the accumulated PSD value is averaged as the final output, and the RMS value corresponding to the selected frequency range can also be calculated, and is recorded and stored uniformly.

[0070] In this example, the amplitude of the segmented acceleration data is adjusted by using the Hanning window, the Hanning window widens the main lobe and reduces the main lobe width by 1 times compared with the main lobe width of the rectangular window function, and the side lobe is significantly reduced, which is better than the rectangular window from the point of view of reducing leakage, and the expression of the Hanning window used in the application is:

[0071]

[0072] Since the data segment length M is 2048, when n is 0 or 2047, the output value of the Hanning window is 0, that is, the final operation result of the 0th and the last sample data is always 0, which loses significance, therefore, in order to fully utilize all the sample data, the value of M is taken as 2049, in addition, since the acceleration data sampled from the acceleration sensor is in units of g, which is not the final acceleration value to be calculated, therefore, before windowing the sample value, it also needs to be converted into an acceleration value, therefore, the final Hanning window formula is as follows:

[0073]

[0074] Wherein, n represents the n th sample acceleration data in the data segment.

[0075] In summary, when calculating the PSD, the Welch method is used, that is, by selecting data with a fixed time length of 1 second (2048 sample acceleration data) in the form of segmentation, half of each data is overlapped with the previous segment, that is, after collecting 0.5 seconds of data, the processor starts to form a 1 second data segment by combining the 1024 sample data collected in the current 0.5 seconds and the 1024 sample data collected in the previous 0.5 seconds, a total of 2048 data, then multiplied by the Hanning window to adjust the amplitude of the measured data, then the adjusted data is subjected to fast Fourier transform to calculate the power spectral density PSD, and finally the average value of the power spectral data calculated in the set reporting period is obtained, that is, the final PSD value.

[0076] The application sets the report period as 15 minutes according to the actual operation of the mobile vehicle-mounted CT medical vehicle, and the 15-minute report period is a relatively reasonable time selected after balancing the transportation conditions and the vibration energy size; and the report period is adjustable in actual application, such as 5 minutes, half an hour, 1 hour, etc.; the longer the report period, the more details of the road conditions and vibration conditions affected by the average algorithm are lost, but it is not easy to occur repeated false alarms; the shorter the report period, the more prone to misjudgment, but the shorter the vibration information is more abundant and detailed, which can be adjusted according to actual needs.

[0077] The vibration report contains detailed vibration data, for the calculated power spectral density PSD and the corresponding RMS effective value, the power spectral density PSD can represent the sensitive frequency and vibration energy of the vibration event, and the RMS effective value can represent the size of the impact energy, so it can be used as feature data to provide data support for subsequent classification and identification of vibration / impact event type and severity.

[0078] As shown in Figure 2 In order to realize the vibration monitoring method of the vehicle-mounted CT scanning unit, the application further provides a host computer system for realizing the vibration monitoring of the vehicle-mounted CT scanning unit, which comprises a communication setting module, a running state display module, a parameter configuration module, a sensor calibration module, and a curve control and display module. The functions of each module are described below.

[0079] (1) Communication setting module: This module is used to realize the communication parameter setting of the host computer and the vehicle-mounted vibration sensor device, including serial number, system time, window clock and other parameters. The system time is displayed as the internal time of the vehicle-mounted vibration sensor device. When the host computer is connected, the host computer automatically compares its time with the host computer time. If the time error is greater than 30 seconds, the host computer corrects the time of the vehicle-mounted vibration sensor device through the corresponding time setting command, without the need to judge and correct the time reference by itself.

[0080] (2) Running state display module: This module is used to display the system running state, including USB interface state, disk state, battery state (charging / power supply), battery voltage, battery capacity, clock type and clock frequency.

[0081] (3) Parameter configuration module: this module is used to realize the configuration of system parameters, including running parameters and alarm threshold parameters, the running parameters include the report period length, the overlap ratio and the calculation frequency range of the effective value RMS, the alarm threshold parameters include the RMS alarm threshold, the impact alarm threshold and the PSD alarm threshold, wherein the RMS alarm threshold is the effective value in the corresponding frequency range, which is configured as 4Hz-200Hz in this example; when the g value in the continuous long time (in the pre-set time period) exceeds the set impact alarm threshold, the impact times are recorded in the vibration report, and the impact events meeting the conditions in the whole report period are counted, and after detecting each impact event meeting the conditions, when the system exits the impact alarm threshold, the impact detection in the 1 second time after the current time is not performed again, and the detection is restored again after 1 second, so that multiple counting in one impact is avoided.

[0082] For the PSD alarm threshold, the application provides 20 groups of threshold input interfaces, wherein the PSD monitoring frequency must be greater than 0 to be effective, and in addition, the PSD monitoring frequency must be increased from top to bottom, and when the PSD monitoring frequency of a group is less than or equal to the frequency of the previous group, all the PSD alarm thresholds after the group will be invalid, so the user can fully utilize the rule to set several groups of effective alarm values, and the invalid alarm thresholds in the upper computer interface are displayed in dark color, and the effective thresholds are distinguished by bright color. After the PSD alarm threshold is set and written, the vehicle-mounted vibration sensing device will automatically generate a linearization of all PSD monitoring frequencies and corresponding PSD values based on the coordinate system of double logarithm.

[0083] (4) Sensor calibration module: since the X, Y and Z three-axis acceleration signals of the vehicle-mounted vibration sensing device are alternating current signals, the three-axis acceleration sensor calibration cannot be simply performed by using voltage and g value, and the calibration needs to be performed by using a vibration table and related measuring tools, so the original sampling value curve can be used for calibration, for example, the acceleration sensor is placed on a standard vibration table and vibrated at a fixed acceleration, and the real measurement value corresponding to the maximum acceleration value can be obtained on the original sampling value curve, and the calibration value is calculated by using two-point linearization and written into the vehicle-mounted vibration sensing device.

[0084] In order to calibrate the corresponding analog channel in the simplest way, the upper computer is additionally provided with a calibration auxiliary tool, which is a linear calculator, and by giving two input and output values, the corresponding gain and offset can be automatically calculated and then directly written into the vehicle-mounted vibration sensing device.

[0085] The calibration auxiliary tool is used as follows:

[0086] The vehicle-mounted vibration sensing device is placed on a standard vibration table, and a 20g sinusoidal acceleration is applied in the X-axis direction. At this time, the peak and trough values of the sinusoidal wave are read from the original sampling value curve as 6776 (corresponding to 20g) and -3708 (corresponding to -20g), respectively. Then, 6776 is written into the input value x1, and the output value y1 is written as 20. Similarly, the input value x2 is written as -3708, and the output value y2 is written as -20. At this time, the gain and offset of the channel are automatically calculated in the auxiliary calculator. The calibration data can be written into the vehicle-mounted vibration sensing device by selecting the corresponding axis.

[0087] It should be noted that when using the zero adjustment function, the vehicle-mounted vibration sensing device needs to be stationary for at least 3 seconds, and the curve control needs to be kept on the real-time measurement curve or the original sampling value curve. In this way, the host computer can collect the measurement values when the device is stationary. After the host computer collects the valid offset, the zero adjustment function is enabled. Otherwise, the zero adjustment function is disabled.

[0088] (5) Curve control and display module:

[0089] This module can select the type of data curve display, including real-time measurement curve, original sampling value curve, and power density curve. When the corresponding curve type is selected, the X, Y, and Z axes corresponding curves are displayed in real time in the display interface.

[0090] In addition to the power spectral density PSD and the effective value RMS calculated in the last report period of the vibration report, the host computer software can also display whether the PSD monitoring frequency of the X, Y, and Z axes exceeds the PSD alarm threshold, whether the RMS value exceeds the RMS alarm threshold, and the number of impacts.

[0091] In summary, the present application provides a vibration monitoring method and system for a vehicle-mounted CT scanning unit, which can collect, record, analyze, and store the vibration conditions under vehicle transportation conditions. The vibration energy and impact events received by the vehicle-mounted CT scanning unit within the monitoring frequency range are monitored in real time, accurately, and intuitively. This facilitates the monitoring and analysis of the transportation conditions of valuable equipment and goods such as vehicle-mounted CT scanning units, and provides data support for improving transportation conditions in the future. In addition, the present application adopts edge computing, which does not require other devices to cooperate in data processing and storage at the front end, effectively saving computing resources and overall system overhead. In addition, the present application has strong expandability and can be applied to the vibration condition monitoring of other types of transportation tools and vehicle-mounted valuable goods during transportation.

[0092] The preferred embodiments of the present application have been described above in detail. It should be understood that modifications and variations to the preferred embodiments could be made by those skilled in the art in light of the teachings above without departing from the spirit of the present application. It is therefore to be understood that what is desired to be protected by letters patent is defined by the scope of the claims that follow and that on behalf of which the summary of the application is intended to serve.

Claims

1. A vibration monitoring method for a vehicle-mounted CT scanning unit, characterized in that: The following steps are involved: 1) The vehicle-mounted vibration sensor device collects the three-axis acceleration data of the vehicle-mounted CT scanning unit in real time and performs filtering sampling; 2) Perform spectrum calculation on the sampled three-axis acceleration data to obtain the power spectrum density PSD and the RMS value of the corresponding frequency range, and generate a vibration report.

2. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 1, characterized in that: The step 1) specifically includes the following steps: 11) Configure system parameters according to the actual operation of the mobile CT medical vehicle; 12) Configure the communication protocol of the host computer; 13) According to the configured system parameters and communication protocol, the three-axis acceleration data of the vehicle-mounted CT scanning unit is acquired in real time and filtered and sampled.

3. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 2, characterized in that: In the step 11), the system parameters specifically include system operation related parameters, report output related parameters, system status related parameters and system time related parameters; The system operation related parameters include acceleration sensor calibration parameters, frequency domain calculation parameters and alarm related parameters. The acceleration sensor calibration parameters include acceleration sensor magnification and offset. The frequency domain calculation parameters include reporting period, overlap rate and maximum and minimum values ​​of the PSD frequency range for calculating the RMS value. The alarm related parameters include RMS alarm threshold, PSD monitoring frequency, PSD alarm threshold, impact time and impact alarm threshold. The report output related parameters include the RMS value corresponding to the set PSD frequency range, the PSD value corresponding to each PSD monitoring frequency, and the number of shocks exceeding the shock alarm threshold.

4. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 1, characterized in that: In step 12), the communication protocol uses a master-slave response mode for data communication. The data format of the request frame and the response frame of the communication protocol are composed of a frame header, a command, a length, data, and a check bit. The frame header is used to distinguish between the master and the slave. The commands include reset, read parameters, read measurement data, and read report commands. The length is specifically the length of the data plus the length of the check code.

5. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 1, characterized in that: The step 2) specifically comprises the following steps: 21) Segmentally reorganize the collected acceleration data according to the sampling frequency and overlap rate of the acceleration data; 22) Multiplying the segmented and reorganized acceleration data segments by a Hanning window to adjust the amplitude; 23) Fast Fourier transform is used to calculate the spectrum and obtain the power spectrum density PSD and the RMS value of the corresponding frequency range.

6. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 5, characterized in that: In step 22), considering that the acceleration data sampled from the acceleration sensor is in units of g, the formula for using the Hanning window is: Wherein, n represents the nth sampled acceleration data in the segmented and reorganized data segment.

7. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 5, characterized in that: In step 23), after performing a fast Fourier transform on the segmented and reorganized acceleration data segment at the current moment to obtain the power spectral density PSD at the current moment, all power spectral densities PSD within the reporting period are continuously obtained and the PSD average value is calculated as the power spectral density PSD within the current reporting period, and the RMS value of the corresponding frequency range is calculated based on this.

8. The vibration monitoring method for a vehicle-mounted CT scanning unit according to claim 3, characterized in that: Based on the actual operation of the mobile CT medical vehicle, the sampling frequency of the acceleration data is set to 2048 Hz, the maximum and minimum values ​​of the PSD frequency range for calculating the RMS value are set to 4 Hz and 200 Hz respectively, the overlap rate is set to 50%, the number of PSD monitoring frequencies is set to 20, and the corresponding PSD alarm thresholds are a total of 60. The maximum analyzable frequency range of the power density curve in the vibration report is 1024 Hz, and the resolution is 1 Hz.

9. The vibration monitoring method of a vehicle-mounted CT scanning unit according to claim 3, characterized in that: When the acceleration value collected by monitoring is continuously higher than the set shock alarm threshold and the duration exceeds the set shock time, it is determined that an impact event has occurred, and the number of shocks is added to the vibration report. When the acceleration value collected by monitoring is lower than the set shock alarm threshold and lasts for 1 second, the impact event monitoring is exited to avoid counting an impact event multiple times.

10. A vibration monitoring system for implementing the vibration monitoring method according to any one of claims 1 to 9, characterized in that: The system includes: Communication setting module: used to set the communication parameters between the host computer and the vehicle-mounted vibration sensor device; Operation status display module: used to display the system operation status; Parameter configuration module: used to configure system parameters; Sensor calibration module: used to obtain the calibration value of the acceleration sensor by two-point linearization calculation based on the original sampling value curve of acceleration, and equipped with calibration auxiliary tools; Curve control and display module: used to select the type of data curve display, including real-time measurement curves corresponding to the X, Y, and Z axes, original sampling value curves, and power density curves.

Images