Oil shortage fault identification method for reversing box of railway engineering vehicles

Abstract

A method for identifying an oil shortage fault in a reversing box of a rail engineering vehicle is provided. The method collects high-frequency vibration monitoring signals, processes the signals based on short-time Fourier transform, compares the signal differences under two working conditions, namely, normal oil supply and oil shortage fault, finds three fault ridge bands, extracts the amplitude energy corresponding to the three ridge bands, takes the root mean square value of the energy curve, and finally constructs two indicators, namely, meshing energy ratio OME21 and meshing energy ratio OME31, by using the root mean square value of the energy curve. When both the meshing energy ratio OME21 and the meshing energy ratio OME31 are less than 1.5 at the same time, the oil supply of the reversing box is normal. Otherwise, it is regarded as an oil shortage fault, thereby realizing the identification of the reversing box oil shortage fault. The method is simple and easy to implement, and the reversing box oil shortage fault diagnosis is accurate and efficient, and has good engineering use value.

Description

Technical Field

[0001] The invention belongs to the technical field of monitoring and diagnosis of rail engineering vehicles, and in particular relates to a method for identifying an oil shortage fault in a reversing box of a rail engineering vehicle. Background Art

[0002] Rail engineering vehicles provide all-round protection for the construction and operation of rail transit, and their operation scope covers engineering construction traction, inspection, rescue, maintenance, etc. Rail engineering vehicles provide safety protection for rail transit, and their own installation protection should be paid more attention, so the monitoring and diagnosis technology and system of rail engineering vehicles came into being.

[0003] In the monitoring and diagnosis of rail engineering vehicles, the diagnosis of the oil shortage fault of the reversing box is an important problem that needs to be solved; on the rail engineering vehicle, a generator is used to drive two sets of bogies to move, and the forward and reverse reversing operations must be completed, all of which are achieved through the reversing box. During the working process, the reversing box has one input and two outputs. In addition to the normal transmission speed and torque, it also has to bear the reversing function. Its structure is complex and has many functions. It is very difficult to monitor and diagnose it. It is basically difficult to see the oil shortage fault of the reversing box. Occasionally, the oil shortage fault of the equipment is mostly studied from the perspective of the oil tank level. In the reversing box, there is no special oil tank. A small amount of hydraulic oil is circulated inside the reversing box through an oil pump, and there is no condition for installing a liquid level sensor; the monitoring and diagnosis of the reversing box requires real-time performance, which further aggravates the difficulty of research. Therefore, it is necessary to make improvements to the above problems. Summary of the invention

[0004] The technical problem solved by the present invention is as follows: a method for identifying an oil shortage fault in a reversing box of a rail engineering vehicle is provided, a high-frequency vibration monitoring signal is collected, the signal is processed based on a short-time Fourier transform, the signal difference under two working conditions of normal oil supply and oil shortage fault is compared, three fault ridge bands are found, and then the amplitude energy corresponding to the three ridge bands is extracted, the root mean square value of the energy curve is taken, and finally the root mean square value of the energy curve is used to construct two indicators of meshing energy ratio OME21 and meshing energy ratio OME31. When the meshing energy ratio OME21 and the meshing energy ratio OME31 are both less than 1.5, the reversing box oil supply is normal, otherwise, it is regarded as an oil shortage fault, thereby realizing the identification of the reversing box oil shortage fault. The method is simple and easy to implement, the reversing box oil shortage fault diagnosis is accurate and efficient, and has good engineering use value.

[0005] The technical solution adopted by the present invention is a method for identifying an oil shortage fault in a reversing box of a rail engineering vehicle, comprising the following steps:

[0006] 1) Collect high-frequency vibration monitoring signals of the reversing box of rail engineering vehicles, process the monitored high-frequency vibration monitoring signals based on short-time Fourier transform, compare the differences in high-frequency vibration monitoring signals under two working conditions: normal oil supply and oil shortage fault of the reversing box, find out three fault ridge bands, extract the amplitude energy curves corresponding to the three ridge bands, and take the root mean square value of all data of the energy curve;

[0007] 2) Using the RMS value of the energy curve, two indicators, meshing energy ratio OME21 and meshing energy ratio OME31, are constructed. When both the meshing energy ratio OME21 and the meshing energy ratio OME31 are less than 1.5 at the same time, the oil supply of the reversing box is normal. Otherwise, it is regarded as an oil shortage fault.

[0008] In the above step 1), the specific steps of taking the root mean square value of all data of the energy curve are as follows:

[0009] S1: Collect the high-frequency vibration monitoring signal of the reversing box of the rail engineering vehicle with a length of N, and record it as x(n), n = 1, 2, ..., N, and its corresponding speed signal is f m ;

[0010] S2: The formula for short-time Fourier transform of x(n) is as follows:

[0011]

[0012] Where, T>0 and F>0 are the sampling periods of the time variable and frequency variable respectively, m and k are integers, which are the serial numbers corresponding to T and F respectively, h*(nT-mT) is the window function, and formula ① maps the acceleration signal x(n) from the time domain to the two-dimensional plane of time and frequency. As the time variable T changes, the window function h*(nT-mT) slides in the time domain, and x(n) is intercepted within the window function to obtain the spectrum, and a three-dimensional spectrum on (T, F, Y) is obtained;

[0013] S3: By comparing the three-dimensional spectra under normal oil supply and oil shortage conditions, the difference in high-frequency vibration monitoring signals under the two conditions can be found. Then, the three fault ridges PY are found according to the automatic search method. 1 (m,k),PY 2 (m,k),PY 3 (m, k), and finally find the amplitude energy curves of the three fault ridges through the following formula:

[0014]

[0015]

[0016]

[0017] Where K is the fault ridge PY 1 (m,k),PY 2 (m,k),PY 3 The maximum data number in the frequency direction of (m, k) is used to calculate the root mean square value of the amplitude energy curve of the three fault ridge bands according to the following formula:

[0018]

[0019]

[0020]

[0021] Where M is the fault ridge belt PY 1 (m,k),PY 2 (m,k),PY 3 The maximum data sequence number in the time direction of (m,k), E 1 (m), E 2 (m), E 3 The average value of (m).

[0022] In the above step S3), three fault ridges PY are found according to the automatic search method. 1 (m,k),PY 2 (m,k),PY 3 The specific steps of (m,k) are as follows:

[0023] S31: Compare the three-dimensional spectra under normal oil supply and oil shortage fault conditions, extract the two curves under normal oil supply and oil shortage fault with m=1, compare and manually mark the frequency coordinates of the centers of the three fault ridge bands when m=1 and their corresponding serial numbers k1, k2, k3, and then the center coordinates of the three fault ridges are obtained

[0024] S32: By coordinates As the starting point, with positive and negative speed signals f m As the range, the maximum central amplitude of the three fault ridges at each time point m is found by the following formula:

[0025]

[0026]

[0027]

[0028] S33: Update the frequency coordinates of the ridge center at each time point based on the maximum amplitude of the three fault ridge belt centers:

[0029]

[0030]

[0031]

[0032] S34: f1 new , As the starting point, with positive and negative speed signals f m For the range, obtain three fault ridgeline curves:

[0033]

[0034]

[0035]

[0036] In the above step 2), the determination of the two indicators of the meshing energy ratio OME21 and the meshing energy ratio OME31 and the determination of whether the reversing box is in a normal oil supply or oil shortage fault include the following steps:

[0037] First, calculate the meshing energy ratio OME21 and meshing energy ratio OME31 according to the following formula:

[0038]

[0039]

[0040] Then, the oil shortage fault is judged by the two indicators of meshing energy ratio OME21 and meshing energy ratio OME31. When the meshing energy ratio OME21 and the meshing energy ratio OME31 are both less than 1.5, the oil supply of the reversing box is normal, otherwise, it is regarded as a reversing box oil shortage fault.

[0041] The advantages of the present invention compared with the prior art are:

[0042] 1. This technical solution does not require the liquid level data of the reversing box. It only needs to extract the fault characteristics from the high-frequency vibration monitoring data and construct indicators that can characterize the oil circuit status of the reversing box. It can identify the oil shortage fault of the reversing box in real time, which is simple and easy to operate;

[0043] 2. This technical solution uses short-time Fourier to extract the fault ridge band and construct indicators from the ridge band, which can accurately identify the reversing box oil shortage fault;

[0044] 3. This technical solution is simple and easy to implement. In addition to monitoring the high-frequency vibration monitoring signal of the reversing box, no other monitoring and diagnostic equipment needs to be installed. The diagnosis of the reversing box oil shortage fault is accurate and efficient, and has good engineering use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a short-time Fourier spectrum of normal oil supply to the reversing box of the present invention;

[0046] Figure 2 It is the short-time Fourier spectrum of the reversing box oil shortage fault of the present invention;

[0047] Figure 3 This is a diagram showing the difference between normal oil supply and oil shortage fault indicators of the reversing box of the present invention;

[0048] Figure 4 This is a fault indicator diagram of the reversing box of the present invention in a semi-oil-deficient state.

[0049] Figure 1 and Figure 2 It is a three-dimensional coordinate graph, the two horizontal axes are the power frequency multiple f and time t, and the vertical axis is the amplitude; Figure 3 The horizontal axis is the meshing energy ratio OME21, and the vertical axis is the meshing energy ratio OME31, where "*" indicates normal oil supply and "O" indicates oil supply failure; Figure 4 In general, the horizontal axis is the meshing energy ratio OME21, the vertical axis is the meshing energy ratio OME31, "*" indicates normal oil supply, "□" indicates semi-oil shortage fault, and "O" indicates oil supply and oil shortage fault. DETAILED DESCRIPTION

[0050] The following will be combined with the embodiments of the present invention Figure 1-4 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions. The elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0052] The method for identifying the oil shortage fault of the reversing box of a rail engineering vehicle comprises the following steps:

[0053] 1) Collect high-frequency vibration monitoring signals of the reversing box of rail engineering vehicles, process the monitored high-frequency vibration monitoring signals based on short-time Fourier transform, compare the differences in high-frequency vibration monitoring signals under two working conditions: normal oil supply and oil shortage fault of the reversing box, find out three fault ridge bands, extract the amplitude energy curves corresponding to the three ridge bands, and take the root mean square value of all data of the energy curve;

[0054] The specific steps of taking the root mean square value of all data of the energy curve are as follows:

[0055] S1: Collect the high-frequency vibration monitoring signal of the reversing box of the rail engineering vehicle with a length of N, and record it as x(n), n = 1, 2, ..., N, and its corresponding speed signal is f m ;

[0056] S2: The formula for short-time Fourier transform of x(n) is as follows:

[0057]

[0058] Wherein, T>0 and F>0 are the sampling periods of the time variable and the frequency variable respectively, m and n are integers, which are the serial numbers corresponding to T and F respectively, h*(nT-mT) is the window function, h is the symbol for function conversion, and j is a symbol for discrete Fourier expansion, which are all well known in the industry; Formula ① maps the acceleration signal x(n) from the time domain to the two-dimensional plane of time and frequency. As the time variable T changes, the window function h*(nT-mT) slides in the time domain, and x(n) is intercepted within the window function to obtain the spectrum, and a three-dimensional spectrum on (T, F, Y) is obtained;

[0059] S3: By comparing the three-dimensional spectra under normal oil supply and oil shortage conditions, the difference in high-frequency vibration monitoring signals under the two conditions can be found. Then, the three fault ridges PY are found according to the automatic search method. 1 (m,k),PY 2 (m,k),PY 3 (m, k), and finally find the amplitude energy curves of the three fault ridges through the following formula:

[0060]

[0061]

[0062]

[0063] Where K is the fault ridge PY 1 (m,k),PY 2 (m,k),PY 3The maximum data number in the frequency direction of (m, k) is used to calculate the root mean square value of the amplitude energy curve of the three fault ridge bands according to the following formula:

[0064]

[0065]

[0066]

[0067] Where M is the fault ridge belt PY 1 (m,k),PY 2 (m,k),PY 3 The maximum data sequence number in the time direction of (m,k), E 1 (m), E 2 (m), E 3 The average value of (m);

[0068] According to the automatic search method, three fault ridges PY are found. 1 (m,k),PY 2 (m,k),PY 3 The specific steps of (m,k) are as follows:

[0069] S31: Compare the three-dimensional spectra under normal oil supply and oil shortage fault conditions, extract the two curves under normal oil supply and oil shortage fault with m=1, compare and manually mark the frequency coordinates of the centers of the three fault ridge bands when m=1 and their corresponding serial numbers k1, k2, k3, and then the center coordinates of the three fault ridges are obtained

[0070] S32: By coordinates As the starting point, with positive and negative speed signals f m As the range, the maximum central amplitude of the three fault ridges at each time point m is found by the following formula:

[0071]

[0072]

[0073]

[0074] S33: Update the frequency coordinates of the ridge center at each time point based on the maximum amplitude of the three fault ridge belt centers:

[0075]

[0076]

[0077]

[0078] S34: f1 new , As the starting point, with positive and negative speed signals f m For the range, obtain three fault ridgeline curves:

[0079]

[0080]

[0081]

[0082] 2) Using the RMS value of the energy curve, two indicators, meshing energy ratio OME21 and meshing energy ratio OME31, are constructed. When both the meshing energy ratio OME21 and the meshing energy ratio OME31 are less than 1.5 at the same time, the oil supply of the reversing box is normal. Otherwise, it is regarded as an oil shortage fault.

[0083] The determination of the two indicators of the meshing energy ratio OME21 and the meshing energy ratio OME31 and the determination of whether the reversing box oil supply is normal or lacks oil include the following steps:

[0084] First, calculate the meshing energy ratio OME21 and meshing energy ratio OME31 according to the following formula:

[0085]

[0086]

[0087] Then, the oil shortage fault is judged by the two indicators of meshing energy ratio OME21 and meshing energy ratio OME31. When the meshing energy ratio OME21 and the meshing energy ratio OME31 are both less than 1.5, the oil supply of the reversing box is normal, otherwise, it is regarded as a reversing box oil shortage fault.

[0088] Example:

[0089] This embodiment provides the specific process of the present invention in the reversing box oil shortage fault test, and verifies the effectiveness of the invention.

[0090] A reversing box is subjected to an oil shortage fault test. The high-frequency vibration signals of 10KHz are collected under the two conditions of normal oil supply and oil shortage fault at a reversing box speed of 2000r / min. Short-time Fourier analysis is performed on the signals. By observation, the center coordinates of three fault ridge bands with meshing frequency of 40 times, 80 times and 120 times are selected when m=1. The three-year fault ridge bands are automatically searched out according to steps S31-S34. The meshing energy ratio OME21 and meshing energy ratio OME31 are calculated according to step 2). Figure 3 As shown in FIG. 1 , it can be seen that the use of “OME21 and OME31 are both less than 1.5” can distinguish between normal oil supply and oil shortage faults. To further verify the adaptability of the present invention, a semi-oil shortage fault under the same speed condition is added, such as Figure 4 As shown, it can be found that "OME21 and OME31 are both less than 1.5" can distinguish between normal and semi-oil shortage faults.

[0091] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0092] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for identifying a fault of lack of oil in a reversing box of a rail engineering vehicle, characterized in that The following steps are involved: 1) Collect high-frequency vibration monitoring signals of the reversing box of rail engineering vehicles, process the monitored high-frequency vibration monitoring signals based on short-time Fourier transform, compare the differences in high-frequency vibration monitoring signals under two working conditions: normal oil supply and oil shortage fault of the reversing box, find out three fault ridge bands, extract the amplitude energy curves corresponding to the three ridge bands, and take the root mean square value of all data of the energy curve; 2) Using the RMS value of the energy curve, construct two indicators: meshing energy ratio OME21 and meshing energy ratio OME31. When both the meshing energy ratio OME21 and the meshing energy ratio OME31 are less than 1.5 at the same time, the oil supply of the reversing box is normal. Otherwise, it is considered as an oil shortage fault. In the above step 1), the specific steps of taking the root mean square value of all data of the energy curve are as follows: S1: Collect the high-frequency vibration monitoring signal of the reversing box of the rail engineering vehicle with a length of N, and record it as x(n), n = 1, 2, ..., N, and its corresponding speed signal is f m ; S2: The formula for short-time Fourier transform of x(n) is as follows: Where, T>0 and F>0 are the sampling periods of the time variable and frequency variable respectively, m and k are integers, which are the serial numbers corresponding to T and F respectively, h*(nT-mT) is the window function, and formula ① maps the acceleration signal x(n) from the time domain to the two-dimensional plane of time and frequency. As the time variable T changes, the window function h*(nT-mT) slides in the time domain, and x(n) is intercepted within the window function to obtain the spectrum, and a three-dimensional spectrum on (T, F, Y) is obtained; S3: By comparing the three-dimensional spectra under normal oil supply and oil shortage conditions, the difference in high-frequency vibration monitoring signals under the two conditions can be found. Then, the three fault ridges PY are found according to the automatic search method. 1 (m,k),PY 2 (m,k),PY 3 (m, k), and finally find the amplitude energy curves of the three fault ridges through the following formulas ②-④: Where K is the fault ridge PY 1 (m,k),PY 2 (m,k),PY 3 The maximum data number in the frequency direction of (m, k) is used to calculate the root mean square values ​​of the amplitude energy curves of the three fault ridge bands according to the following formulas ⑤-⑦: Where M is the fault ridge belt PY 1 (m,k),PY 2 (m,k),PY 3 The maximum data sequence number in the time direction of (m,k), E 1 (m), E 2 (m), E 3 The average value of (m); In the above step 2), the determination of the two indicators of the meshing energy ratio OME21 and the meshing energy ratio OME31 and the determination of whether the reversing box is in a normal oil supply or oil shortage fault include the following steps: First, according to the following formula Calculate the meshing energy ratio OME21 and meshing energy ratio OME31: Then, the oil shortage fault is judged by the two indicators of meshing energy ratio OME21 and meshing energy ratio OME31. When the meshing energy ratio OME21 and the meshing energy ratio OME31 are both less than 1.5, the oil supply of the reversing box is normal, otherwise, it is regarded as a reversing box oil shortage fault.

2. The method for identifying oil shortage fault of a rail engineering vehicle reversing box according to claim 1 is characterized in that: In the above step S3), three fault ridges PY are found according to the automatic search method. 1 (m,k),PY 2 (m,k),PY 3 The specific steps of (m,k) are as follows: S31: Compare the three-dimensional spectra under normal oil supply and oil shortage fault conditions, extract the two curves under normal oil supply and oil shortage fault with m=1, compare and manually mark the frequency coordinates of the centers of the three fault ridge bands when m=1 and their corresponding serial numbers k1, k2, k3, and then the center coordinates of the three fault ridges are obtained S32: By coordinates As the starting point, with positive and negative speed signals f m As the range, the maximum central amplitude of the three fault ridges at each time point m is found by the following formulas ⑧-⑩: S33: Update the frequency coordinates of the ridge center at each time point based on the maximum amplitude of the three fault ridge belt centers: S34: f1 new , f3 new As the starting point, with positive and negative speed signals f m For the range, obtain three fault ridgeline curves: 。

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