JP7128775B2 - Snow accretion estimation method - Google Patents

Description

The present invention relates to a method for estimating the amount of snow accreted on a vehicle.

When a vehicle (e.g., Shinkansen) runs on snow-covered tracks in a snowfall area, the snow on the track is blown up and adheres to the underfloor equipment of the vehicle and the cover plate of the bogie, etc. and grows (hereinafter referred to as "snow accretion") called.). If such accumulated snow falls while the vehicle is running, there is a risk that ground equipment will be damaged or that the vehicle will be caught in a turnout, causing a non-switching accident.

In order to suppress the occurrence of damage due to such accretion of snow, snow removal work is carried out on vehicles, for example, at stations. In order to carry out such snow removal work more effectively and efficiently, it is necessary to predict the amount of snow accretion with high accuracy. (Non-Patent Document 1).

Specifically, in Non-Patent Document 1, as a method for predicting the amount of snow that will grow on the bogie of a vehicle, first, snow density is obtained based on weather data along the railway. Next, based on the snow density and the traveling speed of the vehicle, the amount of snow rising is obtained. Then, the amount of snow accretion on the bogie of the vehicle is estimated from the relationship between the amount of snow rising and the amount of snow accretion that has been measured in advance.

Shigeru Kamata, 4 others, "Prediction method of snow accretion on vehicle bogie considering snow quality on track", Railway Technical Research Institute Report, Vol. 29, No. 1, Jan. 2015, p11-p16

As shown in Non-Patent Document 1, the amount of snow accretion for a vehicle traveling in a predetermined section is predicted. However, the "predetermined section" in which the amount of snow accretion for the vehicle is calculated indicates the distance between stations. I couldn't.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to appropriately estimate the amount of snow accretion for a vehicle traveling in a predetermined section. Specifically, the predetermined section is divided into a plurality of small sections, the amount of snow accretion is estimated for each small section, and the amount of snow accretion for each small section is integrated.

To achieve the above object, the present invention provides a method for estimating the amount of snow accretion for a vehicle traveling in a predetermined section, which divides the predetermined section into a plurality of small sections, and calculates the amount of snow on the track based on the weather data of the small sections. estimating the amount of snow rising from the traveling speed of the vehicle and the snow quality; determining the relationship between a predetermined amount of snow accretion and the amount of snow rising due to travel of the vehicle; The amount of snow accretion in the small section is calculated from the amount of rising snow, and the calculated integrated value of the amount of snow accretion in the small section is estimated as the amount of snow accretion in the predetermined section.

According to the present invention, the amount of snow accretion is estimated by dividing a predetermined section (for example, between stations) into small sections. By calculating the amount of increase in the amount of snow accretion for each small section, the growth rate of snow accretion for each small section can be calculated. In addition, since the amount of snow accretion can be estimated based on a predetermined relationship, it is easy to estimate the amount of accretion of snow.

The growth speed of snow accretion on the vehicle decreases as the snow accretion on the vehicle grows. Also, the amount of soaring is determined based on the snow quality and the running speed of the vehicle.

The snow quality is determined by the air temperature, hours of sunshine and amount of precipitation in the predetermined section.

The relationship may be corrected by comparing the estimated amount of snow accretion in the predetermined section with the actually measured amount of snow accretion in the predetermined section.

Correcting the relationship includes calculating an average error between an estimated value of the amount of snow accretion in the predetermined section and an actual value of the amount of snow accretion in the predetermined section, and determining the amount of snow accretion in the predetermined section based on the average error. A hit rate of estimation relative to actual measurement may be calculated, and the relationship may be corrected so as to improve the hit rate.

ADVANTAGE OF THE INVENTION According to this invention, the amount of snow accretion with respect to the vehicle which drive|works a predetermined area can be estimated appropriately.

It is an explanatory view explaining an example of a snow accretion amount estimation method. FIG. 2 is a flow diagram showing main steps of a method for estimating the amount of accreted snow. FIG. 4 is a plot diagram showing the relationship between snow quality and flying snow flux. FIG. 4 is an explanatory diagram showing the relationship between snow quality and flying snow flux; FIG. 4 is a plot diagram showing the relationship between flying snow flux and snow accretion growth rate; FIG. 2 is a flow diagram showing main steps of a method for estimating the amount of accreted snow. FIG. 10 is a flowchart showing main steps of a snow accretion amount estimation method according to the second embodiment; It is a graph which shows the measurement result of the time-dependent change of the amount of snow accretion. It is a graph which shows the comparison result of the actual value of the snow density in an Example, and an estimated value. 7 is a graph showing comparison results between actual measurement values and estimated values of the amount of snow accretion in Examples.

A method for estimating the amount of accreted snow according to the present invention will be described below with reference to the drawings. In this specification, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<Snow accretion estimation method>
FIG. 1 is an explanatory diagram for explaining an example of a method for estimating the amount of accreted snow according to the present embodiment. FIG. 2 is a flowchart showing main steps of the snow accretion amount estimation method according to the present embodiment.

In estimating the amount of snow accretion according to the present embodiment, as shown in FIG. 1, the distance between stations XY (between station X and station Y ) is divided into a plurality of, for example, three sub-sections A, B, and C, and the amount of snow m on the vehicle is estimated for each of the sub-sections A, B, and C. In the following description, the case of estimating the snow accretion amount m for the small section A will be described as an example, but the snow accretion amount estimation for the small sections B and C is also performed in the same manner.

As shown in FIG. 2, when estimating the amount of accreted snow m in the small section A, first, the snow quality ρ is estimated based on the weather data D1 in the small section A (step S1 in FIG. 2). Here, the "snow quality" according to the present invention is representative of the snow quality of the surface layer of snow that accumulates on orbit due to snowfall.

The weather data D1 used for estimating the snow quality ρ uses the temperature, amount of precipitation, and hours of sunshine measured at predetermined observation points between the stations XY. Note that the instantaneous value for the temperature on the hour is used, and the hourly integrated value is used for the amount of rainfall and sunshine duration.

The amount of snow accretion on the vehicle is considered to have a positive correlation with the amount of snow that is blown up by the running of the vehicle.

Therefore, based on the snow quality ρ estimated in step S1 and the traveling speed data D2 of the vehicle traveling in the small section A, the amount of accumulated snow on the track that is blown up by the traveling vehicle (hereinafter referred to as "flying snow flux F") ) is estimated (step S2 in FIG. 2).

Also, based on the relationship R1 between the flying snow flux F estimated in step S2 and the snow accretion growth speed Vs of the snow accretion with respect to the vehicle, and the time during which the vehicle travels in the light section in the small section A (light travel time data D3). , the amount m of accreted snow on the vehicle is estimated (step S3 in FIG. 2).

The amount of accreted snow m on the vehicle in the small section A is estimated as described above. Then, the amount of snow accretion is estimated in the same way for the small sections B and C, and the amount of snow accretion m estimated for each of the small sections A, B, and C is integrated to obtain the amount of snow accretion between stations XY. A snow amount M is estimated.

The amount of accreted snow M between stations XY is estimated as described above.

The method of dividing the XY between stations, that is, the setting of small sections can be arbitrarily performed. For example, in estimating the snow accretion amount M according to the present embodiment as described above, since the snow quality ρ is calculated based on the weather data D1 for each of the small sections A, B, and C, the observation of the weather data D1 by region. XY between stations may be divided.

Also, the predetermined section for estimating the amount of accreted snow M can be arbitrarily set. That is, the predetermined section does not have to be a section connecting the adjacent station section X and station section Y, and another station section may be arranged between the station section X and the station section Y, for example. Further, for example, either or both of the start point and the end point of the predetermined section may not be the station section.

Next, the details of each process for estimating the amount of accreted snow m will be described.

<Snow Quality Estimation>
First, the method of estimating the snow quality ρ shown in step S1 of FIG. 2 will be described.

The snow on the orbit will melt on the surface due to, for example, the outside temperature and solar radiation, and the density will increase. When the density of the snow surface increases in this way, the snow particles are packed on the snow surface and become less likely to scatter, and the flying snow flux F decreases. That is, it becomes difficult to soar when the vehicle is running.

Note that the flying snow flux F is considered to have a correlation with the snow quality ρ of the snow surface. Therefore, as described above, the hourly weather data D1 is used to calculate the surface snowmelt amount N, which will be described later, and thereby the hourly snow quality ρ is calculated. Here, for example, when there is new snowfall, the calculation up to that point is reset and the snow quality ρ is newly calculated.

A snow surface layer snow density estimation model for calculating changes in snow quality ρ on orbit can be expressed as in the following equation (1).

Here, in equation (1), _ρs indicates the snow density before snowmelt, and _ρs1 indicates the snow density after snowmelt. For the snowfall density ρ _s0 given as the initial value, an empirical formula for the short-time snowfall density determined by the air temperature may be used. Also, _nN indicates the snowmelt mass. The surface snowmelt amount of accreted snow as the snowmelt mass _nN can be calculated from the amount of sunshine estimated from, for example, the air temperature and the hours of sunshine.

<Estimation of flying snow flux>
FIG. 3 is a plot diagram showing an example of the relationship between the estimated snow quality ρ and the flying snow flux F. In FIG. The plot diagram shown in FIG. 3 was calculated by giving the meteorological data at the observation point where the flying snow flux F was actually measured as input values to the surface layer snow density estimation model described above. The flying snow flux F was measured by a flying snow flow meter at the observation point by measuring the amount of snow swirling up due to the passage of vehicles.

As shown in FIG. 3, it was found that while the flying snow flux F shows a large value when the snow surface layer has a low density, it decreases as the snow surface layer has a high density. This is presumably because the snow particles are packed on the surface of the snow as described above, making it difficult for them to scatter.

It should be noted that the flying snow flux F changes according to the running speed of the vehicle. FIG. 4 is an explanatory diagram showing an example of the relationship between the snow flux F according to the traveling speed of the vehicle and the estimated snow quality ρ.
Specifically, as shown in FIG. 4, as the traveling speed of the vehicle increases, the flying snow flux F increases, that is, it is more likely to be blown up.

From this, it is possible to derive a correlation between the flying snow flux F and the estimated snow quality ρ in at least the predetermined section in which the amount of accreted snow M is estimated, more specifically in the traveling speed range of the vehicle in the small section A. desirable.

<Estimation of snow accretion>
As described above, when estimating the amount of accreted snow in the present embodiment, the relationship R1 between the flying snow flux F and the accreted snow growth rate Vs is derived in advance. Then, based on the relationship R1, the light travel time data D3, and the estimated flying snow flux F, the amount of accreted snow m in the small section A is estimated.

FIG. 5 is a plot diagram showing an example of the relationship R1 between the flying snow flux F and the snow accretion growth speed Vs with respect to the vehicle. The snow accretion growth speed Vs is a value obtained by dividing the measured value of the snow accretion amount m for the vehicle in an arbitrary section (for example, the small section A) by the light travel time of the vehicle in the small section A.

As shown in FIG. 5, in the present embodiment, a regression equation (solid line in the figure) of the calculated snow accretion growth rate Vs was obtained. Furthermore, as a relational expression on the safe side of the regression equation, the flying snow flux F is classified by 0.01 kg/m ² /s, the average value and standard deviation σ of each class are obtained, and the average + 1σ is added to the safety A regression equation (broken line in the figure) was obtained for the points on the left side.

As shown in FIG. 5, it was found that the snow accretion growth rate Vs tends to increase as the flying snow flux F increases. In other words, it was found that the amount of snow per unit time m on the vehicle increases with an increase in the amount of soaring snow.

It should be noted that, as described above, the number of divisions of the predetermined section is not limited to this embodiment. In the present embodiment, the predetermined section is divided into three sub-sections A to C, but by increasing the number of divisions, the amount of accreted snow M can be estimated with higher accuracy.

<Snow accretion amount estimation method according to the second embodiment>
Note that the snow accretion amount estimation method described above may incorporate a learning system for improving the accuracy of the estimation method.

FIG. 6 is a flowchart showing main steps of a snow accretion amount estimation method according to the second embodiment. In FIG. 6, elements having substantially the same functional configuration as in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the snow accretion amount estimation method according to the second embodiment, first, the snow accretion amount m in the small section A is estimated in the same manner as the snow accretion amount estimation method shown in FIG. 2 (steps S1 to S3 in FIG. 6). .

When the snow accretion m in the small section A is estimated, next, the estimated snow accretion m (hereinafter, estimated snow accretion ms) and the snow accretion m in the small section A as the actual measurement data D4 (hereinafter , and the actual snow accretion amount ma). Then, the hit rate of the snow accretion amount estimation according to the present invention is calculated by such comparison, and the hit rate is fed back to the relationship R1 between the flying snow flux F and the snow accretion growth speed Vs (step S4 in FIG. 6). . As a result, the relationship R1 is corrected so that the hit rate in the snow accretion estimation is optimized, and the snow accretion m in the next small section A is estimated based on the new corrected relationship R1.

By repeating such feedback correction and estimation of the amount of snow m, the estimation of the amount of snow m is optimized, and the accuracy of the amount of snow accretion according to the present invention can be improved.

FIG. 7 is a flow chart showing main steps of a method for correcting the relationship R1 in accumulating snow amount estimation according to the second embodiment.

As shown in FIG. 7, when correcting the relationship R1, first, the estimated snow accretion amount ms and the actually measured snow accretion amount ma are compared (step P1 in FIG. 7). Then, the average error σ between the estimated snow accretion amount ms and the actually measured snow accretion amount ma is calculated by such comparison (step P2 in FIG. 7). When the relationship R1 is corrected for the first time, the difference between the estimated snow accretion amount ms and the actual snow accretion amount ma can be regarded as the average error σ.

Next, using the calculated average error σ, the likelihood of the estimated snow accretion amount ms is confirmed. Specifically, it is determined whether or not the measured snow accretion amount ma is within the average error σ from the estimated snow accretion amount ms (step P3 in FIG. 7), and the hit rate of the snow accretion amount estimation is calculated ( step P4).

If the actual snow accretion amount ma falls within the range of the estimated snow accretion amount ms±σ, that is, if the actual snow accretion amount agrees with the estimated snow accretion amount (P3-1 in FIG. 7). Also, when the measured snow accretion amount ma is smaller than the estimated snow accretion amount ms−σ, that is, when the actual snow accretion amount is smaller than the estimated snow accretion amount, it is assumed to be a miss (P3-2 in FIG. 7). . Also, the case where the measured snow accretion amount ma is larger than the estimated snow accretion amount ms+σ, that is, the case where the actual snow accretion amount is larger than the estimated snow accretion amount is overlooked (P3-3 in FIG. 7). I judge. Then, the hit rate, miss rate, and miss rate of snow accretion estimation are calculated from the determination result (step P4 in FIG. 7).

Once the hit rate of snow accretion estimation is estimated, then the relationship R1 is corrected (step P5 in FIG. 7). Here, the relationship between the flying snow flux F and the snow accretion growth rate Vs can be expressed by the following equation (2).

In equation (2), α and β are correction coefficients determined by the hit rate, miss rate, and miss rate. In step P5, the values of the correction coefficients α and β shown in equation (2) are corrected so that the miss rate and miss rate are minimized, that is, the hit rate is optimized. Correct the relationship R1 by

Then, the relationship R1 after such correction is used as the relationship R1 in estimating the amount of snow accretion in the next small section A.

As described above, according to the present invention, it is possible to estimate the amount of snow M on a vehicle in a predetermined section. Specifically, it is possible to easily estimate the amount of accreted snow M based on weather data in a predetermined section. Further, according to the present invention, the snow accretion amount M is estimated by dividing the predetermined section into arbitrary small sections and accumulating the estimated snow accretion amount ms for each small section. It is possible to estimate the amount of snow accretion with high accuracy.

In addition, it is possible to determine whether or not snow clearing work is necessary at an arbitrary station only by acquiring the weather data D1 for a predetermined section.

Further, as described above, according to the present invention, the amount of accreted snow m is estimated in consideration of the growth rate of snow accretion Vs, which decreases as the amount of accreted snow m increases. As a result, the amount of accreted snow m is more appropriately estimated for each sub-section divided as described above.

Since the amount of snow accretion can be estimated with high accuracy for each small section in this manner, countermeasures against snow accretion damage can be appropriately taken at each point. In other words, it is possible to determine a priority section for snow countermeasure equipment.

Furthermore, according to the present invention, the snow accretion amount can be repeatedly estimated by correcting the relationship R1 according to the comparison result between the estimated snow accretion amount ms and the actual snow accretion amount ma. As a result, it is possible to estimate the snow accretion amount with higher accuracy.

In addition, in estimating the above-mentioned amount M of accreted snow, the estimation was performed on the assumption that the amount of accreted snow monotonically increases with the passage of time. In other words, it was assumed that the snow accretion growth speed Vs with respect to the vehicle is constant. On the other hand, the inventors have found that the snow accretion growth rate Vs decreases as the snow accretion progresses, that is, as the snow amount m on the vehicle increases.

FIG. 8 is a graph schematically showing the measurement results of the amount of snow accreted on the vehicle over time. As shown in FIG. 8, the amount of accreted snow M on the vehicle sharply increases from a predetermined time T1 to time T2, and the increase slows down after time T2. At time T3, the amount of accreted snow M reaches the upper limit, and thereafter the amount of accreted snow M does not increase (so-called steady state). That is, it is conceivable that there is an upper limit value for the amount M of snow accretion on the vehicle, and that snow accretion does not progress after reaching the steady state.

In other words, the snow accretion growth speed Vs with respect to the vehicle (corresponding to the slope of the tangential line of the snow accretion amount M in the figure) gradually decreases with the lapse of time. After reaching the steady state (after time T3), the snow accretion growth rate Vs becomes zero.

In this way, the snow accretion growth speed Vs on the vehicle decreases over time. Specifically, the snow accretion growth rate Vs decreases as the snow accretion amount M on the vehicle increases, and finally reaches a steady state in which the snow accretion amount M does not increase.

As described above, the snow accretion growth rate Vs increases with an increase in the flying snow flux F, while it decreases with an increase in the amount of accreted snow m. Here, in estimating the snow accretion amount M for the vehicle according to the present invention, the XY between stations as a predetermined section is divided into a plurality of small sections A to C, and the snow accretion amount m is estimated for each of the small sections. do. That is, according to the present invention, it is possible to correct the relationship R1 based on the amount m of accreted snow in the small section A, and to obtain the amount m of accreted snow in the small section B based on the corrected relationship R1.

As described above, according to the present invention, for example, the amount of snow m in the small section B is estimated based on the amount of snow m in the small section A, and based on the integrated value of the amount of snow m in the small sections A and B, The amount of accreted snow m in the small section C can be estimated. As a result, it is possible to estimate the amount of accreted snow m in each small section with higher accuracy, and as a result, it is possible to estimate the amount of accreted snow M in the predetermined section with higher accuracy.

Although the preferred embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive various modifications or modifications within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. accepted as a thing.

The effects of the present invention will be described below based on examples. In this embodiment, in verifying the effect of estimating the amount of snow accretion, the estimated value of the accretion length of snow from the covering plate of the vehicle bogie was compared with the actual value.

FIG. 9 shows (a) a graph showing changes in air temperature and global solar radiation as weather data used in this embodiment, and (b) measured values and estimated values of snow density under the weather conditions shown in (a). and is a comparison graph. In this embodiment, the parameters are determined so as to match the changes in the actual snow density values under the conditions shown in FIG.

In the present embodiment, a Shinkansen was assumed as the vehicle, and the amount of accreted snow was estimated using the relationship between the estimated snow density and the flying snow flux when the running speed was 240 km/h or higher.

The flying snow flux in this example was obtained by measuring the amount of snow rising due to the passage of a vehicle at an observation point using a flying snow flow meter. The flying snow flux was measured by the snow flowmeter for 30 seconds each time the vehicle passed the observation point, and the average value of the measured snow flux for 30 seconds was obtained. Then, the snow quality of the snow surface on the orbit was estimated from the meteorological data at the observed snow flux observation point, and the relational expression of the measured snow flux was obtained.

FIG. 10 is a graph showing the result of comparison between the measured value and the estimated value of the amount of snow accretion in this embodiment.

As shown in FIG. 10, the estimated values show good agreement with the measured values, and it was confirmed that the maximum amount of snow accretion (snow accretion length) on the vehicle can be estimated with an average error of about 3 cm.

INDUSTRIAL APPLICABILITY The present invention is useful for estimating the amount of snow accretion on a vehicle, and further for examining the necessity of snow removal work and priority sections for introduction of snow countermeasure equipment based on the predicted amount of snow accretion. is also useful.

A Small section B Small section C Small section D1 Meteorological data D2 Travel speed data D3 Light travel time data D4 Snow accretion data ma Measured value (of snow accretion) ms Estimated value (of snow accretion) R Relationship X Station area Y Station area ρ Snow quality

Claims (6)

A method for estimating the amount of snow accretion for a vehicle traveling in a predetermined section,
dividing the predetermined section into a plurality of small sections;
estimating the snow quality on the orbit from the weather data of the small section;
estimating the amount of snow rising from the traveling speed of the vehicle and the snow quality;
calculating the amount of snow accretion in the small section from the relationship between a predetermined amount of snow accretion and the amount of snow rising due to travel of the vehicle, and the estimated amount of snow rising;
A method for estimating the amount of snow accretion, wherein the calculated integrated value of the amount of accretion of snow in the small section is estimated as the amount of accretion of snow in the predetermined section. 2. The method for estimating the amount of accreted snow according to claim 1, wherein the growth rate of accreted snow on the vehicle decreases as the accretion of snow on the vehicle increases. 3. The method for estimating the amount of accreted snow according to claim 1 or 2, wherein the amount of rising snow is determined based on the quality of snow and the running speed of the vehicle. 4. The method for estimating the amount of snow accretion according to claim 3, wherein said snow quality is determined by temperature, hours of sunshine and amount of precipitation in said predetermined section. 5. The method according to any one of claims 1 to 4, wherein the relationship is corrected by comparing the estimated amount of snow accretion in the predetermined section with the actually measured amount of snow accretion in the predetermined section. method for estimating snow accretion. calculating an average error between the estimated value of the amount of snow accretion in the predetermined section and the measured value of the amount of snow accretion in the predetermined section;
calculating an estimated hit rate for the actual measurement of the amount of snow accretion in the predetermined section based on the average error;
6. The snow accretion amount estimation method according to claim 5, wherein said relationship is corrected so as to improve said hit rate.

Images