JP7027297B2 - Anomaly detection method for air springs for railway vehicles - Google Patents

Description

The present invention relates to an abnormality detection method for an air spring for a railway vehicle, and more particularly to an abnormality detection method effective for preventing erroneous detection and erroneous determination due to a stop on a relaxation curve.

The pressures of the air springs provided on the left and right sides of the front bogie of the railcar and the air springs provided on the left and right sides of the rear bogie are measured, and the measured pressures are used to detect the abnormalities in the air springs. Patent Documents 1 and 2 show a method of determining the inclination of a vehicle and whether or not the traveling speed is appropriate corresponding to the inclination and ensuring the safety of traveling.

In the railroad vehicle safe running system shown in Patent Document 1, the difference in the weight of the running wheels applied to the left and right wheels of the front bogie or the rear bogie while the railcar is running at a speed equal to or higher than the initial value is calculated, and the difference in the running wheel weights of the railcar is calculated. Based on the speed and the condition of the railroad car, the estimated wheel load difference that will be applied to the left and right wheels of the front bogie or the rear bogie at the running position of the rail car is calculated.
Further, in this railroad vehicle safe driving system, a risk factor in a railroad vehicle is calculated from the above-mentioned estimated wheel load difference, and when the risk factor exceeds a predetermined risk factor, the speed of the railroad vehicle is reduced. I do.

However, Patent Document 1 is a system that calculates the risk factor based on the pressure difference between a pair of air springs located on the left and right of each bogie (front bogie, rear bogie), so that the vehicle can follow the relaxation curve where the cant changes. It is not possible to grasp the malfunction when the car is stopped and the car body is twisted.
Further, in Patent Document 1, there is a problem that the air spring is determined to be abnormal even though the air spring is normal while the vehicle is running or stopped in a state of excess cant or insufficient cant.

Then, in order to prevent the above-mentioned problems, Patent Document 2 uses the diagonal imbalance of the air spring and combines this with the left-right imbalance to more accurately determine the abnormal state of the air spring. A method has been proposed.
Specifically, Patent Document 2 discloses air spring abnormality detection for detecting abnormalities in air springs provided on the left and right sides of a front bogie arranged on the front side of the vehicle body and a rear bogie arranged on the rear side of the vehicle body. In the system, the first judgment means for determining whether the diagonal imbalance of the vehicle body is large, the second determination means for determining whether the left-right imbalance of the vehicle body is large, and the air spring are abnormal. It has an abnormality determining means for determining whether or not it is.

Then, in Patent Document 2, the abnormality determination means, for example, while traveling in a medium-high speed range, has a large diagonal imbalance, continues for a predetermined time (10 seconds or more as a specific example), and is in the left-right direction. When the imbalance is small, it is determined that the air spring is abnormal.

Japanese Patent No. 5582892 Japanese Unexamined Patent Publication No. 2016-159643

In the case of railroad vehicles, if the station is located on the relaxation curve due to the terrain, it may be necessary to stop on the relaxation curve with a cant when the signal is instructed or when an emergency stop is required. When a railroad vehicle is stopped on this relaxation curve with a cant, there is a difference between the cant at the front bogie position and the cant at the rear bogie position, so in a stopped state that is not affected by centrifugal force etc. Since the front and rear bogies incline according to the cant, it is inevitable that the car body will be in a twisted state.
This twist is absorbed by a total of four air springs provided on the left and right sides of the front bogie and the rear bogie having different heights.
That is, the pressure of each air spring is unbalanced by supplying and exhausting the individual air springs until the individual height falls within a predetermined height range by the automatic height adjusting valve provided therein. It is known that the diagonal imbalance increases with the air springs located diagonally to the vehicle body.

Then, in the air spring abnormality detection system shown in Patent Document 2, the detection data of the pressure sensor that detects the pressure of each air spring is measured every hour, and based on the diagonal imbalance of the vehicle body calculated from the detection data. , The abnormality judgment as to whether or not the air spring is abnormal is performed.
However, in Patent Document 2, conditions such as the magnitude of the left-right imbalance, the duration of the diagonal imbalance, and the traveling speed are complicatedly involved as the criterion for detecting the abnormality of the air spring. As a result, there was a problem in determining the abnormality of the air spring.

In an actual railroad vehicle, the train may unintentionally stay on the line for a long time on a relaxation curve with a large twist due to the disorder of the timetable, etc. At this time, in Patent Document 2, the diagonal imbalance (maximum) temporarily increased. (About 1.0), but it takes an unexpected amount of time to return to the normal unbalanced value even after restarting the operation, and it may be erroneously determined that an abnormality has occurred in the normal air spring.
In Patent Document 2, in order to exclude such a state from the determination, conditions such as considering the duration of the diagonal imbalance and performing the determination only at a certain speed or higher are set. However, in this case, there is a problem that the processing content becomes complicated, an unexpectedly long duration or a high running speed must be set, and the time during which the abnormality determination cannot be made becomes long.

The present invention has been made in view of the above-mentioned circumstances, and is an air spring for a railway vehicle capable of accurately determining an abnormality of an air spring based on a diagonal imbalance of a vehicle body based on a simple determination condition. Provide an abnormality detection method .

In order to solve the above problems, the present invention proposes the following means.
In the method for detecting an abnormality in an air spring for a railroad vehicle according to the first aspect of the present invention, the front side trolley located on the front side of the vehicle body of the railway vehicle and the rear side trolley located on the rear side of the vehicle body are provided on the left and right sides, respectively. In addition, the measurement process for measuring the pressure of the air springs that adjust the distance between the trolley and the vehicle body, and the diagonal imbalance value of the air springs arranged diagonally are calculated as the moving average for each predetermined distance of the vehicle body. It is characterized by having a calculation step for determining the presence or absence of an abnormality in the air spring based on a comparison result between the calculated moving average and a preset reference value.

In the abnormality detection device for the air spring for a railway vehicle shown in the second aspect of the present invention, the front side trolley located on the front side of the vehicle body of the railway vehicle and the rear side trolley located on the rear side of the vehicle body are provided on the left and right sides of each. An air spring that adjusts the distance between the trolley and the vehicle body, a pressure sensor that measures the pressure of each of these air springs, and an abnormality that determines the abnormality of each air spring based on the pressure measured by these pressure sensors. The abnormality determination unit includes a determination unit, and the abnormality determination unit calculates and calculates the moving average of the diagonally unbalanced values of the air springs arranged diagonally among the plurality of air springs for each predetermined distance of the vehicle body. It is characterized in that the presence or absence of an abnormality in the air spring is determined based on the result of comparison between the moving average and the reference value.

According to the present invention, a moving average for each predetermined distance of a railroad vehicle is calculated for the diagonal unbalanced value of the air springs arranged diagonally, and the air is based on the comparison result between the moving average and the preset reference value. The presence or absence of an abnormality in the spring was determined.
As a result, in the present invention, since the moving average of the diagonal imbalance value of the air spring is calculated for each predetermined distance of the railcar, the vehicle is on a large relaxation curve of twist in which the cant changes due to the disturbance of the timetable or the like. The moving average of the diagonal imbalance value does not become extremely large regardless of whether the line has been on the line for a long time or only for a short time.
That is, in the present invention, the diagonal imbalance value of the air spring is calculated by calculating the moving average every time the railroad vehicle travels a predetermined distance, not every time the railroad vehicle travels for a certain period of time. It is possible to accurately determine the abnormality of the air spring based on the diagonal imbalance of the vehicle body without being affected by changes in the operating conditions.
Further, in the present invention, the presence or absence of an abnormality in the air spring can be determined based on the comparison result between the moving average of the diagonal imbalance value of the air spring and the preset reference value. Efficient abnormality judgment can be performed without requiring complicated judgment conditions.

It is a side view of the railroad vehicle of this embodiment. FIG. 1 is a front view of FIG. 1. It is a top view which shows the position of the air spring (AS1 to AS4) in the railroad vehicle of FIGS. 1 and 2. It is a flowchart which concerns on the air spring abnormality detection processing which is executed in the abnormality determination part at the time of traveling of a railroad vehicle 100. It is a graph showing the abnormality judgment status of the air spring for each distance. (A) is the pressure change of the air springs (AS1 to AS4), and (B) is the change of the diagonal imbalance value calculated from the pressure of the air spring. , (C) show the change of the traveling speed for each position (1 km scale unit in the graph).

An abnormality detection method and an abnormality detection device for air springs in a railway vehicle 100 applied to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 is a side view showing the railway vehicle 100 of the present embodiment, and FIG. 2 is a view of FIG. 1 viewed from the front. FIG. 3 is a plan view showing the positions of the air springs (AS1 to AS4) in the vehicle body 1 of FIGS. 1 and 2.

In FIGS. 1 to 3, the front-rear direction, which is the traveling direction of the railway vehicle 100 along the track, is defined as the "arrow a1-a2 direction", and the vertical direction, which is the height direction, is defined as the "arrow b1-b2 direction". , The left-right directions orthogonal to each of the front-back direction and the up-down direction are shown as "arrows c1-c2 directions".

As shown in FIGS. 1 to 3, the railroad vehicle 100 shown in the present embodiment includes a vehicle body 1, a front side trolley 2 arranged on the front side of the vehicle body 1, and a rear side arranged on the rear side of the vehicle body 1. The trolley 3, the air springs AS1 to AS4 provided on the left and right sides of the front trolley 2 and the rear trolley 3, pressure sensors P1 to P4 for detecting the pressures of the air springs AS1 to AS4, and these pressure sensors P1. It has an abnormality determination unit 10 for detecting an abnormality of the air springs AS1 to AS4 based on the detected values of the air springs AS1 to P4.

In the configuration shown in FIGS. 1 to 3, the air springs AS1 to AS4, the pressure sensors P1 to P4, and the abnormality determination unit 10 constitute an abnormality detection device 101 (see FIG. 2) according to the present embodiment.
Further, as the air springs AS1 to AS4, when viewed from the center of the vehicle along the traveling direction, the front right air spring AS1 which is the right air spring of the front side trolley 2 and the left air spring of the front side trolley 2 are attached to one vehicle body 1. The front left air spring AS2, the rear right air spring AS3 which is the right air spring of the rear trolley 3, and the rear left air spring AS4 which is the left air spring of the rear trolley 3 are provided.
Further, as the pressure sensors P1 to P4, for example, existing pressure sensors for measuring the internal pressure of the air spring for brake control can be used.

Further, a height adjusting mechanism 20 is further provided on each vehicle body 1 of the railway vehicle 100.
As shown in FIG. 1, the height adjusting device 20 has a source air reservoir 21 in which compressed air generated by a compressor or the like is sequentially stored, and an automatic height adjusting valve LV in the middle, and the source air. A branch pipe 22 is provided to supply the compressed air stored in the reservoir 21 to the air springs AS1 to AS4, respectively, and to discharge the compressed air inside the air spring (note that in FIG. 1, the air springs AS1 and AS3 are connected to each other). Only the branch pipe 22 to be used is described).
These automatic height adjusting valves LV supply air from the original air reservoir 21 if the heights of the air springs AS1 to AS4 are lower than the predetermined value, and exhaust the internal air of the air springs AS1 to AS4 to the atmosphere if the height is higher than the predetermined value.

The compressed air stored in the original air reservoir 21 acts as a working fluid that expands and contracts the heights of the air springs AS1 to AS4.
Then, in these automatic height adjusting valve LVs, the air springs AS1 to AS1 to each of the air springs AS1 to AS4 correspond to the distance between the vehicle body 1, the front side bogie 2, and the rear side bogie 3 so that the air springs AS1 to AS4 maintain a predetermined height. Supply and exhaust to AS4.
Here, in the automatic height adjusting valve LV, when the vehicle 100 is traveling on a track where the cant changes, the heights from each part of the bogies 2 and 3 to each part of the vehicle body 1 become uneven at four points. At this time, by adjusting the supply and exhaust to each of the air springs AS1 to AS4, the heights of the air springs AS1 to AS4 are all adjusted to the same height.
As a result, in the vehicle 100, a force in the torsional direction is applied to the vehicle body 1, an imbalance occurs in the internal pressures of the air springs AS1 to AS4, and the diagonal imbalance value becomes large, whereby the bogie 2 , 3 wheel load fluctuation becomes large.

The abnormality determination unit 10 is composed of, for example, a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. Various data and programs are stored in the ROM. The CPU reads the specified program from the ROM, expands it into the RAM, and performs abnormality determination processing based on the expanded program.

Specifically, the abnormality determination unit 10 performs, for example, the air spring abnormality detection process shown in the flowchart of FIG. 4 while the vehicle body 1 is traveling.
The following processing flow is performed continuously at the time of departure of the train and during the temporary stop of the train. That is, the processing flow of FIG. 4 is executed with the movement of the vehicle.
<< Step S1 >>
At the same time as the railroad vehicle 100 starts traveling, the measurement of the mileage is started based on the traveling position data (km data) acquired from the vehicle monitoring device or the like.

<< Step S2 >>
In the four air springs AS1 to AS4 arranged in the vehicle body 1, pressure data is taken from the pressure sensors P1 to P4 for detecting the internal pressure and stored in the memory.

<< Step S3 >>
The pressure data AS1 to AS4 of the air springs AS1 to AS4 stored in step S2 are read out, and the pressure data AS1 to AS4 are smoothed.
Since the smoothing at this time is mainly for noise reduction, time-based smoothing is used. Although this smoothing is necessary for removing electrical noise, it is not always necessary to carry out this smoothing in an environment with less noise, and this step S4 may be omitted.

<< Step S4 >>
The diagonal imbalance value (A) is calculated by the formula 1 using the pressure data AS1 to AS4 of the air springs AS1 to AS4 as input values.
Diagonal imbalance value (A) = ((AS1 + AS4)-(AS2 + AS3)) / (AS1 + AS2 + AS3 + AS4)
…… Formula 1

In this step S4, as shown in Equation 1, the sum of the internal pressure of the front right air spring AS1 and the internal pressure of the rear left air spring AS4, and the sum of the internal pressure of the front left air spring AS2 and the internal pressure of the rear right air spring AS3. The diagonal imbalance value (A) is calculated by dividing the diagonal pressure difference, which is the difference from the above, by the sum of these four internal pressures.

<< Step S5 >>
Based on the measured value in step S1, it is determined whether or not the measured value of the mileage of the vehicle body 1 has reached 100 m, which is the minimum distance unit. Return to step S2 of.
In step S5, the mileage is grasped based on the mileage data (kilometer data) acquired from the vehicle monitor device or the like, but the mileage is not limited to this, and the mileage is integrated instead of the mileage data itself. You may use the distance data obtained by doing so.

<< Step S6 >>
The diagonal imbalance value (A) calculated in step S5 is stored in the memory.
That is, by sequentially performing the processes of steps S2 to S6 described above, the diagonal imbalance value (A) is stored in the memory in step S6 every time the vehicle body 1 travels a predetermined measurement distance (100 m in the embodiment). ..

<< Step S7 >>
The moving average value is calculated from the latest 100 points of data stored in the memory in step 6. Here, 100 points of memory data correspond to a mileage of 10 km.
That is, by sequentially performing the above-mentioned processes of steps S2 to S7 together with the traveling of the railway vehicle, the moving average value is calculated for 10 km of the diagonal imbalance value (A) in step S8 every time the vehicle body 1 travels 100 m. do.

<< Step S8 >>
It is determined whether or not the diagonal imbalance value (A) calculated in step S7 exceeds a predetermined threshold value Th (for example, about 0.2), and if NO, the air springs AS1 to AS4 operate normally. If yes, the process returns to the previous step S2, and if YES, the process proceeds to the next step S9.

<< Step S9 >>
As a result of the determination, it is assumed that an abnormality has occurred in the air springs AS1 to AS4, and an alarm signal for notifying the abnormality to the monitoring device of the driver's cab is output, and the process returns to the previous step S2.

In the series of processing steps for determining the abnormality shown in the flowchart, steps S1 and S2 correspond to the measurement process, steps S3 to S7 correspond to the calculation process, and steps S8 and S9 correspond to the determination process.
Further, in the calculation steps (steps S3 to S7), the diagonal is calculated and smoothed based on the pressure values of the air springs AS1 to AS4 for each predetermined minimum distance unit (100 m in the case of the embodiment). From the first step (step S6) for storing the unbalanced value (A) and the diagonal unbalanced value (A) stored in the first step, a predetermined distance (10 km) for leveling the state of the orbit. ) A second step (step S7) of calculating a moving average value for each.

Next, with reference to FIGS. 5A to 5C, a specific example of the abnormality determination of the air spring based on the processing content of the flowchart shown in FIG. 4 will be described.
The graphs shown in FIGS. 5A to 5C show the pressure changes of the air springs AS1 to AS4 and the air when the vehicle body 1 passes through a station on a relaxation curve having a twist in the track. The change of the diagonal imbalance value (A) calculated from the pressures of the springs AS1 to AS4 and the change of (C) the traveling speed are shown for each position (indicated in 1 km scale units in the graph).

First, it corresponds to the case where the vehicle body 100 stops at a station having a twist in the track such as a relaxation curve (a station in the middle of a section where the cant is not constant) at the position indicated by the reference numeral M1 in FIG. 5 (C). As for the internal pressure of the air spring at the position, AS1 and AS4 located diagonally may decrease and AS2 and AS3 may increase as indicated by reference numeral M2 in FIG. 5 (A).
The reason why such a phenomenon occurs is that a cant is provided on the relaxation curve, and the trajectory is twisted by gradually increasing the cant amount toward the curve of the relaxation curve. In the track in such a state, even if the four air springs AS1 to AS4 are normal, the diagonal balance of the vehicle body 1 is lost while the relaxation curve is running or the relaxation curve is stopped.

At this time, as shown by the reference numeral M3 in FIG. 5B, when the diagonal unbalance value A'(absolute value) is obtained by the time-based moving average at regular time intervals, the diagonal unbalance is obtained. The value A'may increase significantly temporarily.
After that, as shown by reference numeral M4 in FIG. 5B, the stopped vehicle 100 is restarted, and the diagonal imbalance value A'returns to the normal value even after passing through the section where the track is twisted. It takes a long time (distance) to complete.
At this time, when the threshold value Th used for determining the abnormality of the diagonal imbalance value is set to "± 0.2", the diagonal imbalance value A when the vehicle 100 is stopped for a long time in a section where the track is twisted. Due to a sudden change in ´, an abnormality may be determined even though the condition is normal.

On the other hand, as shown by reference numeral M5 in FIG. 5B, in the diagonal imbalance A using the measured values smoothed based on the mileage according to the present invention, almost the change is seen even when the station is stopped. I can't. As a result, even when the vehicle body 100 is stopped for a long time in a section where the track is twisted, the diagonal imbalance value A does not change so much, and it is abnormal even though it is in a normal state. It is possible to prevent the judgment from being made.
As described above, in the conventional time-based smoothing in air spring abnormality determination, it is necessary to take measures such as not performing abnormality determination based on the diagonal imbalance value (A') at low speed or when the vehicle is stopped, but distance-based. This is not necessary for smoothing. Therefore, according to this method, it is possible to effectively perform an abnormality determination without any limitation on the time or section that cannot be determined.

As described in detail above, according to the abnormality detection method and the abnormality detection device 101 for the air spring for a railroad vehicle shown in the embodiment of the present invention, the diagonal unbalanced values of the air springs AS1 to AS4 arranged diagonally ( For A), the moving average for each predetermined distance of the vehicle body 1 was calculated, and the presence or absence of abnormality of the air springs AS1 to AS4 was determined based on the comparison result between the moving average and the preset reference value.
As a result, in the present embodiment, the moving average for each predetermined distance of the vehicle body 1 is calculated for the diagonal unbalanced values (A) of the air springs AS1 to AS4, so that the cant changes due to the disorder of the diamond or the like. Even if the vehicle stays on the large relaxation curve for a long time or only for a short time, the moving average of the diagonal imbalance value (A) does not become an extremely large value.

That is, in the present embodiment, by adopting a simple method of calculating the moving average of the diagonal unbalanced values (A) of the air springs AS1 to AS4 for each predetermined distance, not for each fixed time of the vehicle body 1. , It is possible to accurately determine the abnormality of the air springs AS1 to AS4 based on the diagonal imbalance of the vehicle body.
Further, in the present embodiment, the presence or absence of abnormality of the air springs AS1 to AS4 can be determined from the comparison result between the moving average of the diagonal imbalance values (A) of the air springs AS1 to AS4 and the preset reference value. It is possible to efficiently determine the abnormality of the air springs AS1 to AS4 without requiring complicated determination conditions such as the conventional determination of the abnormality of the air spring.

In the calculation steps (steps S3 to S7) of the above embodiment, the smoothed diagonal imbalance value (A) based on the pressure values of the air springs AS1 to AS4 is calculated every 100 m, which is the minimum distance unit. (Step S6), and then, from the diagonal imbalance value (A) of the latest determination distance (10 km), the moving average value in which the orbital state is leveled is calculated (step S7).
At this time, 100 m, which is the minimum distance unit set in step S6, and 10 km, which is the determination distance set in step S7, can be appropriately set and changed depending on the conditions for abnormality determination.

As a rough guideline for the minimum distance unit, it is a relaxation curve that causes fluctuations in the unbalanced value, but considering that it is necessary to add the value during this period to the judgment, about 5 points are required for each relaxation curve. It is thought that it will be. That is, about 20% of the relaxation curve length of a typical sharp curve (a sharp curve generally has a large cant and an imbalance in the relaxation curve tends to be large) existing in the line section to which this method is applied. The length should be the minimum distance unit.
As a rough guideline for the determination distance, it is preferable to keep the length of the relaxation curve at one place within about 5% of the determination distance in order to prevent the fluctuation of the value on the relaxation curve from having a great influence on the determination. That is, it is preferable that the determination distance is about 20 times the length of the typical relaxation curve of the sharp curve of the applicable line section.
Further, the threshold value Th (for example, about 0.2) set as the reference value in step S9 can be appropriately changed according to the state of the line and the like.

Further, in the above embodiment, the diagonal imbalance value (A) obtained in step S4 is corrected by an offset value predetermined for each vehicle in consideration of the error peculiar to the vehicle to be measured and the trolley. Is preferable.

Further, in the above embodiment, the diagonal imbalance value (A) is calculated based on the pressure values of the air springs AS1 to AS4, but the present invention is not limited to this, and the air is replaced with the pressure values of the air springs AS1 to AS4. The diagonal imbalance value (A) may be calculated based on the measured value obtained by measuring the heights of the springs AS1 to AS4.

Further, in the above embodiment, the moving average is used as the smoothing method, but the smoothing method is not limited to this (for example, various low-pass filters can be used).
Further, in Equation 1, the denominator is the sum of the pressure values of the air springs AS1 to AS4. For example, a value corresponding to the average value of the internal pressures of the four air springs used for brake control should be multiplied by four. (In actual use, instead of finding the sum sequentially, it is also possible to use a value obtained by multiplying the value equivalent to the average value of the internal pressures of the air springs at four locations by four).

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like within a range not deviating from the gist of the present invention.

The present invention relates to an abnormality detection method and an abnormality detection device applied to an air spring for a railway vehicle.

1 Body 2 Front bogie 3 Rear bogie 10 Abnormality judgment unit 20 Height adjustment device 21 Original air reservoir 22 Branch piping 100 Railroad vehicle 101 Abnormality detection device A Diagonal imbalance value AS1 to AS4 Air spring P1 to P4 Pressure sensor

Claims (5)

Measurements that measure the pressure of air springs that are provided on the left and right of the front bogie located on the front side of the car body of the railroad vehicle and the rear bogie located on the rear side of the car body, and that adjust the distance between these bogies and the car body. Process and
A calculation process for calculating the moving average of the diagonal unbalanced value of the air spring arranged diagonally for each predetermined distance of the vehicle body, and
It has a determination step of determining the presence or absence of an abnormality in the air spring based on a comparison result between the calculated moving average and a preset reference value.
In the calculation process,
The first step of storing the diagonal imbalance value calculated and smoothed based on the pressure value of the air spring for each predetermined minimum distance unit, and
A railway vehicle characterized by having a second step of calculating a moving average value for each determination distance that is predetermined and the track state is leveled from the diagonal imbalance value stored in the first step. Abnormality detection method for air springs. The method for detecting an abnormality in an air spring for a railway vehicle according to claim 1 , wherein the minimum distance unit and the determination distance are determined based on the relaxation curve length of a typical sharp curve. The diagonal imbalance value in the calculation process is characterized in that it is calculated by dividing the difference between the pressure mean values of each pair of air springs located diagonally by the sum of the pressure mean values of all the air springs. The method for detecting an abnormality in an air spring for a railroad vehicle according to any one of claims 1 and 2 . The one according to any one of claims 1 to 3 , wherein the diagonal imbalance value corrects an error peculiar to a vehicle to be measured and a trolley with an offset value predetermined for each vehicle. Anomaly detection method for air springs for railway vehicles. The invention according to any one of claims 1 to 4 , wherein the diagonal imbalance value is calculated based on the measured value obtained by measuring the height of the air spring instead of the pressure value of the air spring. Abnormality detection method for air springs for railroad vehicles.

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