JP2020091205A - Axle load measuring device, measuring accuracy diagnostic method, and measuring accuracy diagnostic program - Google Patents

Abstract

To make it possible, regardless of the presence or absence of travel of a road-specific vehicle, to determine whether measuring accuracy of axle load sensors arranged side by side in the direction of travel of the vehicle is appropriate.SOLUTION: An axle load sensor connection unit 12 receives input of measurement signals from a plurality of axle load sensors 2 to 4 that are arranged side by side in the direction of travel of a vehicle 100. A difference calculation unit 23 calculates, for the same axle, the difference between the maximum value and the minimum value of measured values according to the measurement signals input from the plurality of axle load sensors 2 to 4. A determination unit 24 determines whether the magnitude of the difference calculated by the difference calculation unit 23 exceeds a difference threshold.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technique for diagnosing whether or not the measurement accuracy of a shaft load sensor that measures the shaft load of a traveling vehicle is appropriate.

Conventionally, there has been a device for measuring the weight of a vehicle traveling on a road. This device processes the measurement signals of a plurality (two or more) of axle load sensors that are embedded in a road and arranged in the traveling direction of the vehicle to measure the weight of the traveling vehicle (see Patent Document 1, etc.). As is well known, the axle load sensor is a sensor used to measure a vertical force (axle weight) when a wheel attached to the axle passes by for each axle of the vehicle.

The axle load of the axle is calculated by processing measurement signals of a plurality of axle load sensors that are embedded side by side in the traveling direction of the vehicle. For example, for each axle, an average value of axle loads measured by a plurality of axle load sensors on the axle is calculated as the axle load of the axle. Further, the weight of the vehicle is the sum (total) of the axle loads calculated for each axle of the vehicle.

Further, Patent Document 1 describes a configuration for performing sensitivity correction (configuration for updating a correction coefficient) for each axle load sensor according to the measurement accuracy of the axle load without interrupting the measurement of the weight of the vehicle. ing. Specifically, for each axle load sensor, the weight of the vehicle calculated using the measurement data when a predetermined specific vehicle (vehicle whose vehicle data such as the number of axles and total weight is known) passes is true. The correction coefficient for correcting the sensitivity is updated so that the value becomes a value.

JP, 2010-261825, A

However, the specific vehicle in Patent Document 1 is
(1) It is a vehicle whose total weight (total value of axle weight of each axle) does not change depending on usage conditions.
(2) It is a vehicle in which there are no other vehicles with similar numbers of axles, distance between axles, axle weight, etc.
The vehicle must meet the conditions in.

Therefore, vehicles such as trucks and trailers for loading cargo do not satisfy the above condition (1). In addition, general passenger cars (private cars and company cars) do not satisfy the above condition (2). For this reason, the specific vehicle had to be a special vehicle rather than a general vehicle. In Patent Document 1, a self-propelled crane is used as a specific vehicle.

If the specific vehicle is a special vehicle, the period from the current traveling of the specific vehicle to the next traveling of the specific vehicle may be long. In the technique according to Patent Document 1, the period for determining the decrease in the measurement accuracy of the axle load sensor is the period from the current traveling of the specific vehicle to the next traveling of the specific vehicle. For this reason, in the technique according to Patent Document 1, there may occur a situation in which it is not possible to determine whether or not the measurement accuracy of the axle load sensor has decreased over a long period of time.

An object of the present invention is to provide a technique capable of determining whether or not the measurement accuracy of axle load sensors arranged side by side in the traveling direction of a vehicle is appropriate, regardless of whether or not a special vehicle is traveling.

The axial load measuring device of the present invention is configured as described below to achieve the above object.

Measurement signals of a plurality of axle load sensors arranged side by side in the traveling direction of the vehicle are input to the axle load sensor connection portion. The difference calculation unit calculates the difference between the maximum value and the minimum value of the measurement values corresponding to the measurement signals input from the plurality of axle load sensors for the same axle. The determination unit determines whether or not the magnitude of the difference calculated by the difference calculation unit exceeds the difference threshold.

A moving vehicle vibrates due to various factors such as road surface irregularities, speed, tire air pressure, etc., which affect each other in a complicated manner. Therefore, even if the measurement accuracy of the plurality of axle load sensors arranged side by side in the traveling direction of the vehicle is appropriate, the measurement value of the axle load measured by these axle load sensors for the same axle is the true value (the relevant Axle weight), to some extent. In other words, if the measurement accuracy of the plurality of axle load sensors arranged side by side in the traveling direction of the vehicle is appropriate, the variation in the axle load measurement values measured by these axle load sensors for the same axle is within a certain range. Fits within. Therefore, by determining whether the magnitude of the difference between the maximum value and the minimum value of the measurement values corresponding to the measurement signals input from the plurality of axle load sensors exceeds the difference threshold (that is, the plurality of axes It is possible to determine whether the measurement accuracy of these axle load sensors is appropriate by determining whether the variation of the axle load measurement values measured by the load sensors is within a certain range). ..

Thus, according to the above configuration, it is possible to determine whether or not the measurement accuracy of the axle load sensors arranged side by side in the traveling direction of the vehicle is appropriate, regardless of whether or not the special vehicle is traveling.

In addition, the axle load measuring device is configured to include a vehicle type estimation unit that estimates a vehicle type, and a threshold setting unit that sets a difference threshold value according to the vehicle type estimated by the vehicle type estimation unit. May be.

The measurement error of the axial load by the axial load sensor is the ratio of the axial load to the true value. That is, the heavier the axle load, the greater the measurement error of the axle load measured by the axle load sensor, and the greater the range of variation in the measured value of the axle load of each axle load sensor. Therefore, by setting the difference threshold value according to the vehicle type, it is possible to suppress the influence of the difference in the vehicle type (vehicle weight) on the determination as to whether the measurement accuracy of the axle load sensor is appropriate.

In addition, the threshold setting unit sets a lower limit threshold value of the axle load according to the vehicle type estimated by the vehicle type estimating unit, and the determining unit determines the measurement value according to the input measurement signal for each axle load sensor. Alternatively, it may be configured to determine whether or not the lower limit threshold is exceeded. According to this structure, it is possible to determine whether or not all the axial load sensors have decreased measurement accuracy in the direction in which the measured value becomes lighter than the true value.

In addition, the threshold setting unit sets an upper limit threshold value of the axle load according to the vehicle type estimated by the vehicle type estimating unit, and the determining unit determines, for each axle load sensor, a measurement value according to the input measurement signal. Alternatively, it may be configured to determine whether or not the upper limit threshold is exceeded. According to this structure, it is possible to determine whether or not the measurement accuracy of all the axial load sensors decreases in the direction in which the measured value becomes heavier than the true value.

The vehicle type estimation unit may be configured to process the frame image of the vehicle captured by the image capturing device to estimate the type of the vehicle, or may include a plurality of axle load sensors arranged side by side in the traveling direction of the vehicle. The type of the vehicle may be estimated based on the number of axes of the vehicle and the distance between the axes detected based on the measurement result of the axle load. The number of axles is the number of axles provided on the vehicle. The inter-axle distance is the distance between two consecutive axles in the direction from the vehicle head side to the vehicle tail side.

Further, the axle load sensor may be a pair of wheel load sensors arranged in the vehicle width direction, or may be an integral type that is not divided into left and right.

Further, it may be configured to include a vehicle weight calculation unit that calculates the weight of the vehicle by using the measurement signals of the plurality of axle load sensors when the vehicle is traveling.

According to the present invention, it is possible to determine whether or not the measurement accuracy of the axle load sensors arranged side by side in the traveling direction of the vehicle is appropriate regardless of whether or not the special vehicle is traveling.

It is a schematic diagram showing a vehicle weight measuring system to which an axle load measuring device concerning this example is applied. It is a block diagram which shows the structure of the principal part of the axial load measuring device concerning this example. 3A to 3C are views showing measurement data of the axle load sensor. It is a figure which shows calculated data. It is a flow chart which shows measurement processing of an axle load measuring device concerning this example. It is a flow chart which shows measurement accuracy diagnostic processing of an axle load measuring device concerning this example. It is a flow chart which shows total processing of an axle load measuring device concerning this example. It is a schematic diagram showing a vehicle weight measuring system to which an axle load measuring device concerning another example is applied. It is a block diagram which shows the structure of the principal part of the axial load measuring device concerning another example. It is a figure explaining threshold value data. It is a flowchart which shows the measuring process of the axial load measuring device concerning another example. It is a flow chart which shows measurement accuracy diagnostic processing of an axle load measuring device concerning another example. It is a flow chart which shows total processing of an axle load measuring device concerning another example. It is a figure explaining an aggregation counter. It is a flowchart which shows the determination process of the axial load measuring device concerning another example.

Hereinafter, an axial load measuring device according to an embodiment of the present invention will be described.

<1. Application example>
FIG. 1 is a schematic diagram showing a vehicle weight measuring system to which an axle load measuring device according to this example is applied. The vehicle weight measuring system shown in FIG. 1 includes an axle load measuring device 1, three axle weight sensors 2 to 4, and two vehicle detection sensors 6 and 7. The axle load sensors 2 to 4 and the vehicle detection sensors 6 and 7 are connected to the axle load measuring device 1.

As shown in FIG. 1, the vehicle detection sensor 6, the axle load sensor 2, the axle load sensor 3, the axle load sensor 4, and the vehicle detection sensor 7 are arranged in this order in the traveling direction of the vehicle 100 (embedded) on the road. Has been done. The measurement section for measuring the axle load of the vehicle 100 is a section from the vehicle detection sensor 6 to the vehicle detection sensor 7. The vehicle detection sensor 6 detects the vehicle 100 entering the measurement section. The vehicle detection sensor 7 detects the vehicle 100 leaving the measurement section.

The axle load sensor 2 includes a pair of wheel load sensors 2R and 2L arranged side by side in the vehicle width direction of a vehicle 100 traveling on a road. Similarly, the axle load sensor 3 is formed by arranging a pair of wheel weight sensors 3R, 3L in the vehicle width direction of the vehicle 100 traveling on a road, and the axle load sensor 4 is a pair of wheel weight sensors 4R, 4L. Are arranged in the vehicle width direction of the vehicle 100 traveling on the road. The wheel load sensors 2R to 4R are embedded at positions where the wheels on the right side of the vehicle 100 pass. In addition, the wheel load sensors 2L to 4L are embedded at positions where wheels on the left side of the vehicle 100 pass. The wheel load sensors 2R to 4R and 2L to 4L are, for example, piezoelectric sensors, and output to the axle load measuring device 1 a measurement signal corresponding to the pressing force when the wheel passes. The vehicle detection sensors 6 and 7 are loop coil sensors, for example, and output a change in inductance to the axle load measuring device 1 as a vehicle detection signal (a signal indicating the presence or absence of the vehicle 100).

The vehicle detection sensors 6 and 7 may be optical sensors or radio wave sensors that are not buried in the road.

The wheel load sensors 2R to 4R output to the axle load measuring device 1 a measurement signal obtained by measuring the wheel load of the right wheel for each axle of the vehicle 100 traveling in the measurement section. Further, the wheel load sensors 2L to 4L output to the axle load measuring device 1 a measurement signal obtained by measuring the wheel load of the left wheel for each axle of the vehicle 100 traveling in the measurement section. That is, in the axle load measuring device 1, for each axle of the vehicle 100 traveling in the measurement section, the wheel weight of the right wheel is measured by the wheel load sensor 2R, the wheel load sensor 3R, and the wheel load sensor. The measurement signal from 4R is input. In addition, the axle load measuring device 1 includes a wheel load sensor 2L, a wheel load sensor 3L, a wheel load sensor 3L, and a wheel load sensor for the wheel load of the left wheel for each axle of the vehicle 100 traveling in the measurement section. The 4L measurement signal is input.

The distance L1 between the axial load sensor 2 and the axial load sensor 3 and the distance L2 between the axial load sensor 3 and the axial load sensor 4 in the traveling direction of the vehicle 100 have different lengths. The vehicle 100 that is running vibrates due to various factors such as road surface irregularities, speed, tire air pressure, etc., which complicately influence each other. If both the distance L1 between the adjacent axial load sensor 2 and the axial load sensor 3 and the distance L2 between the adjacent axial load sensor 3 and the axial load sensor 4 are approximate to an integral multiple of the vibration wavelength of the vehicle 100, the axial load is increased. The measurement error of may increase. Therefore, in this example, one of the distance L1 between the adjacent axial load sensors 2 and 3 or the distance L2 between the adjacent axial load sensors 3 and 4 is an integral multiple of the vibration wavelength of the vehicle 100. The distance L1 and the distance L2 are set to different lengths so that the other does not approximate an integral multiple of the vibration wavelength of the vehicle 100 even if the distance is approximated to.

The axle load measuring device 1 of this example cumulatively stores measurement values corresponding to the input measurement signal for each of the wheel load sensors 2R to 4R and 2L to 4L. In this example, this measurement value will be described as the wheel load calculated using the input measurement signal. However, this measurement value may be any value as long as it is a value corresponding to the input measurement signal. For example, this measurement value may be a digital value of the input measurement signal.

In addition, in this example, that the measurement accuracy of the axle load sensor 2 is appropriate means that the measurement accuracy of the wheel load sensor 2R and the wheel load sensor 2L is appropriate. Similarly, that the measurement accuracy of the axle load sensor 3 is appropriate means that the measurement accuracy of the wheel load sensor 3R and the wheel load sensor 3L is appropriate, and the measurement accuracy of the axle load sensor 4 is appropriate. Means that the measurement accuracy of the wheel load sensor 4R and the wheel load sensor 4L is appropriate. Further, the axle weight measured by the axle weight sensor 2 is the wheel weight measured by the wheel weight sensor 2R for the right wheel attached to the axle and the wheel weight measured by the wheel weight sensor 2L for the left wheel. Is the sum of Similarly, the axle weight measured by the axle weight sensor 3 includes the wheel weight measured by the wheel weight sensor 3R for the right wheel attached to the axle and the wheel weight measured by the wheel weight sensor 3L for the left wheel. The axle load measured by the axle load sensor 4 is the wheel load measured by the wheel load sensor 4R for the right wheel attached to the axle and the wheel load measured by the wheel load sensor 4L for the left wheel. It is the sum of the weight that was made.

Since the traveling vehicle 100 is vibrating, even if the measurement accuracy of the axle load sensors 2 to 4 is proper, the measured value of the axle load measured varies. The variation in the measured value of the axle load falls within a certain range if the measurement accuracy of the axle load sensors 2 to 4 is appropriate (may not fall within a certain range depending on the magnitude of vibration of the vehicle 100). ..).

The axle load measuring device 1 calculates the difference between the maximum value and the minimum value of the axle load measurement values measured by the axle load sensors 2 to 4 for the same axle. The difference calculated here indicates the magnitude of variation in the measured values of the axle loads measured by the axle load sensors 2 to 4 on the same axle. The axle load measuring device 1 determines whether the calculated accuracy of the axle load sensors 2 to 4 is appropriate by determining whether the calculated difference exceeds a difference threshold.

In this way, the axle load measuring device 1 can determine whether or not the measurement accuracy of the axle load sensors arranged side by side in the traveling direction of the vehicle is appropriate, regardless of whether or not the special vehicle is traveling.

<2. Configuration example>
FIG. 2 is a block diagram showing the configuration of the main part of the axial load measuring device according to this example. The axle load measuring device 1 according to this example includes a control unit 11, an axle load sensor connection portion 12, a loop coil sensor connection portion 13, a measurement value database 14 (measurement value DB 14), and an output portion 15. ing.

The control unit 11 controls the operation of each part of the main body of the axial load measuring device 1 according to this example. The control unit 11 also includes a measurement value calculation unit 21, a measurement data generation unit 22, a difference calculation unit 23, and a determination unit 24. The control unit 11 also has a memory (not shown) provided with a storage area for storing a difference threshold, which will be described later. In addition, this memory is provided with a storage area that functions as a difference excess counter, which will be described later, and a determination axis number counter. Details of the measurement value calculation unit 21, the measurement data generation unit 22, the difference calculation unit 23, and the determination unit 24 included in the control unit 11 will be described later.

The shaft weight sensor connection unit 12 receives the measurement signals of the connected shaft weight sensors 2 to 4. Specifically, the wheel load sensors 2R to 4R and 2L to 4L are connected to the axle load sensor connection portion 12, and the measurement signals of the wheel load sensors 2R to 4R and 2L to 4L are input. The axle load sensor connection unit 12 converts the input measurement signals of the wheel load sensors 2R to 4R and 2L to 4L into digital values and outputs them to the control unit 11.

Vehicle detection sensors 6 and 7 are connected to the loop coil sensor connection unit 13. The loop coil sensor connection unit 13 detects a change in inductance for each of the vehicle detection sensors 6 and 7 and outputs a vehicle detection signal indicating the presence or absence of the vehicle 100 to the control unit 11.

The measurement value DB 14 is a database that cumulatively stores the measurement data and the calculated data generated for the vehicle 100 that has traveled in the measurement section. The measurement data generation unit 22 described below generates measurement data and calculation data. The details of the measurement data and the calculation data will be described later.

The output unit 15 determines whether or not the measurement accuracy of the axle load sensors 2 to 4 is appropriate, the measurement data of the vehicle 100 that has traveled in the measurement section, the calculation data, and the like, if necessary, by a higher-level device. Output).

Next, the measurement value calculation unit 21, the measurement data generation unit 22, the difference calculation unit 23, and the determination unit 24 included in the control unit 11 will be described.

The measurement value calculation unit 21 measures the measurement signal when the wheels of the vehicle 100 pass through the wheel load sensors 2R to 4R, 2L to 4L (actually, the wheel load sensors 2R to 4R and 2L to 4L). The wheel load is calculated using the digital value converted by the connection unit 12.

The measurement data generation unit 22 uses the vehicle detection signal input from the loop coil sensor connection unit 13 to divide the wheel weight calculated by the measurement value calculation unit 21 into units of the vehicle 100 traveling in the measurement section. The measurement data generation unit 22 generates measurement data for each of the axle load sensors 2-4. In this example, the measurement data generation unit 22 generates this measurement data for each vehicle 100.

FIG. 3 is a diagram showing measurement data of the axle load sensor. 3A is the measurement data of the axle load sensor 2, FIG. 3B is the measurement data of the axle load sensor 3, and FIG. 3C is the measurement data of the axle load sensor 4. The measurement data shown in FIGS. 3A to 3C are for the same vehicle 100. This measurement data is associated with a vehicle ID that identifies the vehicle 100 as shown in FIG. This vehicle ID is not for identifying the vehicle 100, but for each vehicle 100 traveling in the measurement section, the measurement data of the axle load sensor 2, the measurement data of the axle load sensor 3, and the measurement data of the axle load sensor 4. Is associated with.

In addition, here, the axle closest to the head of the vehicle 100 is the first axle, and the second axle and the third axle are arranged in order toward the tail of the vehicle. The wheel loads (right) of the axle load sensors 2 to 4 shown in FIG. 3 are calculated using the measurement signals of the corresponding wheel load sensors 2R to 4R (indicated by RA1, RB1, RC1, etc. in the figure). It is). The wheel loads (left) of the axle load sensors 2 to 4 shown in FIG. 3 are wheel loads calculated by using the measurement signals of the corresponding wheel load sensors 2L to 4L (indicated by LA1, LB1, LC1, etc. in the figure). It is). Further, the axle weights of the axle weight sensors 2 to 4 shown in FIG. 3 are obtained by using the axle weights calculated using the measurement signals of the corresponding axle weight sensors 2R to 4R and the corresponding axle weight sensors 2L to 4L. It is the sum of the wheel weight calculated by using.

The measurement data shown in FIG. 3 is an example of the vehicle 100 having three axles. In the case of the vehicle 100 having two axles, the measurement data does not include data on the third axle. Further, in the case of the vehicle 100 having four or more axles, the measurement data includes data relating to the fourth axle, the fifth axle, etc. according to the number of axles.

Further, the measurement data generation unit 22 generates the calculation data shown in FIG. This calculation data is calculated based on the measurement results of the axle load sensors 2 to 4. Similar to the measurement data shown in FIG. 3, the calculated data is associated with the vehicle ID for identifying the vehicle 100. This vehicle ID is not for identifying the vehicle 100, but is associated with the measurement data shown in FIG. As shown in FIG. 4, the wheel weight (right), the wheel weight (left), and the axle weight are registered in this calculated data for each axle of the vehicle 100. The wheel load (right) of each axle is the average value of the wheel load of the wheel calculated using the measurement signals of the wheel load sensors 2R to 4R. The wheel load (left) of each axle is the average value of the wheel load of the wheel calculated using the measurement signals of the wheel load sensors 2L to 4L. The axle weight of each axle is the sum of the axle weight (right) and axle weight (left) of that axle. The vehicle weight (ALL), which is the weight of the vehicle 100, is the sum (total) of the axle loads of the vehicle 100.

The measurement data generation unit 22 registers the measurement data of the axle load sensors 2 to 4 generated for each vehicle 100 and the calculation data calculated for the vehicle 100 in the measurement value DB 14.

Although not particularly shown, the measurement data and the calculation data shown in FIG. 3 are also associated with the date and time when the vehicle 100 traveled in the measurement section.

The difference calculation unit 23 refers to the measurement data shown in FIG. 3, extracts the maximum value and the minimum value of the axle load, which are the measurement results by the axle load sensors 2 to 4, for each axle of the vehicle 100, and extracts these. To calculate the difference. Taking the first axis of the vehicle 100 shown in FIG. 3 as an example, the difference calculation unit 23 has the measured value of the axial load sensor 2 (RA1+LA1), the measured value of the axial load sensor 3 (RA2+LA2), and the axial load. The maximum value and the minimum value are extracted from (RA3+LA3) which is the measured value of the sensor 4, and the difference between them is calculated. This difference is the magnitude of variation in the measured values of the axle load sensors 2 to 4 with respect to the corresponding axle.

The determination unit 24 determines whether the difference calculated by the difference calculation unit 23 exceeds a difference threshold value. The difference threshold value is stored in the memory of the control unit 11 as described above. The determination unit 24 also determines whether or not the measurement accuracy of the axle load sensors 2 to 4 is appropriate.

The control unit 11 of the axle load measuring device 1 is composed of a hardware CPU, a memory, and other electronic circuits. When the hardware CPU executes the measurement accuracy diagnosis program according to the present invention, it operates as the measurement value calculation unit 21, the measurement data generation unit 22, the difference calculation unit 23, and the determination unit 24. The memory also has an area for developing the measurement accuracy diagnostic program according to the present invention and an area for temporarily storing data and the like generated when the measurement accuracy diagnostic program is executed. Further, the memory is provided with a storage area for storing the above-mentioned difference threshold, a difference excess counter, and a storage area that functions as a determination axis number counter. The control unit 11 may be an LSI in which a hardware CPU, a memory and the like are integrated. The hardware CPU is a computer that executes the measurement accuracy diagnosis method according to the present invention.

<3. Operation example>
The axle load measuring device 1 according to this example determines whether or not the measurement processing for measuring the axle weight and the vehicle weight and the measurement accuracy of the axle load sensors 2 to 4 are appropriate for the vehicle 100 traveling in the measurement section. Perform measurement accuracy diagnosis processing.

FIG. 5 is a flowchart showing the measurement process of the axle load measuring device according to this example. The axle load measuring device 1 waits for the vehicle 100 to enter the measurement section (s1). The control unit 11 detects that the vehicle 100 has entered the measurement section based on the change in the inductance of the vehicle detection sensor 6 connected to the loop coil sensor connection unit 13.

When it is detected that the vehicle 100 has entered the measurement section, the measurement value calculation unit 21 stores a measurement signal for each of the wheel load sensors 2R to 4R and 2L to 4L connected to the axle load sensor connection unit 12. The data is cumulatively stored in (s2). That is, when it is detected that the vehicle 100 has entered the measurement section, the measurement value calculation unit 21 starts a process of cumulatively storing the measurement signal in the memory for each of the wheel load sensors 2R to 4R and 2L to 4L. To do. The time interval for storing the measurement signals of the wheel load sensors 2R to 4R and 2L to 4L is, for example, several tens msec to several 100 msec.

When it is detected that the vehicle 100 has exited from the measurement section (s3), the measurement value calculation unit 21 accumulates measurement signals in the memory for each of the wheel load sensors 2R to 4R and 2L to 4L started in s2. The process of storing is completed (s4). The measurement value calculation unit 21 processes the measurement signals cumulatively stored in the memory for each of the wheel load sensors 2R to 4R and 2L to 4L, and calculates the wheel load measurement value of each axle (s5).

The measurement signals of the wheel load sensors 2R to 4R and 2L to 4L change when the wheels of the vehicle 100 pass through. Therefore, the measurement value calculation unit 21 can obtain the number of axles of the vehicle 100 by counting the places where the measurement signals of the wheel load sensors 2R to 4R and 2L to 4L have changed. Further, the measurement value calculating unit 21 can calculate the wheel load by extracting the measurement signal when the wheel of each axle passes for each of the wheel load sensors 2R to 4R and 2L to 4L.

The measurement data generation unit 22 generates the measurement data shown in FIG. 3 for the vehicle 100 that has passed the measurement section this time (s6). This measurement data can be generated based on the wheel load of each axle calculated by the measurement value calculation unit 21 for each of the wheel load sensors 2R to 4R and 2L to 4L. Further, the measurement data generation unit 22 generates the calculation data shown in FIG. 4 (s7). This calculation data can be generated based on the measurement data generated in s6. That is, this calculation data can also be generated based on the wheel load of each axle calculated by the measurement value calculation unit 21 for each of the wheel load sensors 2R to 4R and 2L to 4L.

The measurement data generation unit 22 stores the measurement data generated in s6 and the calculation data generated in s7 in the measurement value DB 14 (s8), and returns to s1.

In this way, the axle load measuring device 1 cumulatively stores the measurement data shown in FIG. 3 in the measurement value DB 14 for each vehicle 100 that has passed through the measurement section. Further, the axle load measuring device 1 detects whether or not the vehicle 100 is overloaded, the vehicle 100 is in a partially loaded state in which the load is biased to the left or right, or the like, based on the calculation data generated in s7. Can also be done. Further, the calculation data stored cumulatively in the measurement value DB 14 can be used as useful information for determining the necessity of road repair work or the like.

Next, the measurement accuracy diagnosis process of the axle load measuring device 1 according to this example will be described. The measurement accuracy diagnosis process is a process of diagnosing whether the measurement accuracy of the axle load sensors 2 to 4 is proper. FIG. 6 is a flowchart showing the measurement accuracy diagnosis process. The axle load measuring device 1 determines whether it is a diagnostic timing for diagnosing the measurement accuracy of the axle load sensors 2 to 4 (s11). The diagnosis timing may be, for example, the timing when a set time has elapsed from the end of the previous measurement accuracy diagnosis process, or the number of vehicles 100 that have traveled in the measurement section from the end of the previous measurement accuracy diagnosis process has reached the set number. The timing may be the same. If the set number is set to one, the measurement accuracy diagnosis process can be executed every time the vehicle 100 travels in the measurement section. In addition to the above, the diagnosis timing may be 0:00 am every Monday, 0:00 am on the first day of every month, 0:00 am on the first day of even months or odd months, etc. It may be the timing instructed by.

When the axle load measuring device 1 determines in s11 that it is the diagnostic timing, it determines the target vehicle group (s12). This target vehicle group may be all the vehicles 100 that have traveled in the measurement section during the period from the end of the previous measurement accuracy diagnosis process to the present time, or the vehicle 100 that has passed the measurement section at the end may be one. As a unit, a predetermined number of vehicles that are continuous with the vehicle 100 may be used. The vehicles 100 belonging to the target vehicle group may be limited by the number of axles. For example, the vehicle 100 belonging to the target vehicle group may be provided with conditions such as the vehicle 100 having two axles or the vehicle 100 having three or less axles. When the axle load measuring device 1 determines the target vehicle group in s12, the axle load measuring device 1 executes the aggregation process (s13).

FIG. 7 is a flowchart showing the totaling process in s13. The difference calculation unit 23 determines a determination target axle from the axles of the vehicle 100 belonging to the target vehicle group determined in s12 (s21). In s21, among the axles of the vehicle 100 belonging to the target vehicle group determined in s11, an axle that has not been subjected to the processing of s22 to s25 shown below (an unprocessed axle) is selected. The difference calculation unit 23 calculates a difference (maximum value-minimum value) between the maximum value and the minimum value of the axle loads measured by the axle load sensors 2 to 4 for the axle to be processed determined in s21 (s22). ). For example, when the first axis of the measurement data shown in FIG. 3 is determined as the determination target axle in s21, the difference calculation unit 23 measures the axle load (RA1+LA1) measured by the axle load sensor 2 and the axle load sensor 3. The maximum value and the minimum value are extracted from the calculated axial load (RA2+LA2) and the axial load (RA3+LA3) measured by the axial load sensor 4, and the difference between them is calculated.

The determination unit 24 determines whether the difference calculated by the difference calculation unit 23 in s22 exceeds a difference threshold (s23). The difference threshold value is stored in the memory of the control unit 11 as described above. The vehicle 100 that is running vibrates due to various factors such as road surface irregularities, speed, tire air pressure, etc., which complicately influence each other. Therefore, even if the measurement accuracy of the plurality of axle load sensors 2 to 4 arranged side by side in the traveling direction of the vehicle 100 is appropriate, the axle load sensors 2 to 4 measure the axle load measured on the same axle. The value varies within a certain range with respect to the true value (axle weight of the axle). In other words, if the measurement accuracy of the plurality of axle load sensors 2 to 4 arranged side by side in the traveling direction of the vehicle 100 is appropriate, the axle load sensors 2 to 4 measure the axle load measured on the same axle. The variation of is within a certain range. The difference threshold value is a predetermined value according to the size of this range. Therefore, when the difference calculated in s22 exceeds the difference threshold value, it is highly possible that the axial load is not properly measured by any of the axial load sensors 2 to 4. When the determination unit 24 determines that the difference threshold is exceeded in s23, the determination unit 24 increments the count value of the difference excess counter (count value is incremented by 1) (s24), and increments the count value of the determination axis number counter (s25). ). Further, the count value of the difference excess counter and the count value of the determination axis number counter are reset when it is determined in s11 that the diagnostic timing is reached.

When the determination unit 24 determines in s23 that the difference threshold is exceeded, the determination unit 24 increments the count value of the determination axis number counter in s25 without incrementing the count value of the difference excess counter in s24.

The axle load measuring device 1 determines whether or not there is an unprocessed axle (s26), and if there is an unprocessed axle, the process returns to s21. When the axle load measuring device 1 determines in s26 that there is no unprocessed axle, this aggregation processing ends.

Returning to FIG. 6, when the axial load measuring device 1 finishes the totaling process in s13, the determination unit 24 determines the ratio (Y/X) of the count value Y of the difference excess counter to the count value X of the determination axis number counter. Calculate (s14). As is clear from the above description, the count value X of the determination axis number counter is the number of axles to be processed. Further, the count value Y of the difference exceeded counter is the number of axles determined to exceed the difference threshold in s23. The determination unit 24 determines whether the ratio calculated in s19 is less than or equal to the proper ratio (s15). This proper ratio is caused by an axle whose axle load has not been properly measured in any of the axle load sensors 2 to 4 due to external factors such as vibration of the vehicle 100, noise, etc. In order to prevent erroneous determination that the measurement accuracy of 4 to 4 is not appropriate, it is preferable to set it according to the number of axles to be processed in the above processing. For example, when the number of axles to be processed is several (for example, 2 to 5), a relatively large value of about 0.5 is set, and when the number of axles to be processed exceeds several hundred, 0.1 to 0.1 It is preferable to set it to a relatively small value of about 0.3. This proper ratio is also stored in the memory of the control unit 11.

When the determination unit 24 determines in s15 that the ratio is less than or equal to the appropriate ratio, the determination unit 24 determines that the measurement accuracy of the axle load sensors 2 to 4 is appropriate (s16). On the other hand, if the determination unit 24 determines in s15 that the ratio is not less than the proper ratio, the determination unit 24 determines that the measurement accuracy of the axle load sensors 2 to 4 is not appropriate (s17).

The control unit 11 outputs the determination result of the determination unit 24 (the determination result in s16 or s17) from the output unit 15 to the higher-level device (s18), and ends this processing.

As described above, in the axle load measuring device 1 according to this example, whether the axle load sensors 2 to 4 arranged side by side in the traveling direction of the vehicle 100 are appropriate in measurement accuracy regardless of whether or not a special vehicle is traveling. You can judge whether or not.

The frequency of diagnosing the measurement accuracy of the axle load sensors 2 to 4 can be set every time the vehicle 100 travels in the measurement section, or can be set every certain period, depending on the setting of the diagnosis timing.

Further, in the above example, it is determined whether the difference between the maximum value and the minimum value of the axle loads measured by the axle load sensors 2 to 4 for the same axle exceeds a difference threshold value. It may be determined whether or not the difference between the maximum value and the minimum value of the wheel weights measured for the wheels with the same 4R exceeds the difference threshold value. In this case, it is possible to diagnose whether the measurement accuracy of the wheel load sensors 2R to 4R is proper. Similarly, it may be determined whether the difference between the maximum value and the minimum value of the wheel weights measured by the wheel weight sensors 2L to 4L for the same wheel exceeds a difference threshold value. In this case, it is possible to diagnose whether the measurement accuracy of the wheel load sensors 2L to 4L is proper.

Further, in the above example, the axial load sensors 2 to 4 are composed of the pair of wheel load sensors 2R to 4R and 2L to 4L, but they may be an integrated type which is not divided into left and right. Good.

In addition to the wheel load of each wheel of the vehicle 100, the axle load of each axle of the vehicle 100, and the weight of the vehicle 100 described above, the axle load measuring device 1 measures the speed of the vehicle 100 and the distance between the axles of the vehicle 100. The distance and the like may be measured and additionally registered in the calculation data shown in FIG.

<4. Modification>
Next, an axial load measuring device 1A according to another example will be described. FIG. 8 is a schematic diagram showing a vehicle weight measuring system to which an axle load measuring device according to another example is applied. The vehicle weight measuring system according to this example is different from the above example in that the vehicle weight measuring system includes a camera 8. The camera 8 is connected to the axial load measuring device 1A and outputs the captured frame image to the axial load measuring device 1A. In the axle load measuring device 1A, the camera 8 can associate the vehicle 100 imaged in the frame image with the vehicle 100 traveling in the measurement section, and can estimate the type of the imaged vehicle 100. It is installed so that a frame image can be captured.

In this example, the camera 8 is installed so that the surrounding area where the vehicle detection sensor 6 is installed is used as an imaging area and a frame image in which the entire vehicle 100 entering (or entering) the measurement section can be captured. .. In addition, in this example, the camera 8 is an angle at which the vehicle 100 is imaged with a depression angle from the vehicle head side.

It should be noted that the camera 8 may be installed so as to capture a frame image in which the entire traveling vehicle 100 fits within the measurement section, or the camera 8 may be installed in the vicinity where the vehicle detection sensor 7 is installed. It may be installed so that a frame image in which the entire vehicle 100 exiting (or exiting from) can be captured. Further, the camera 8 may be an angle for taking an image of the vehicle 100 with a depression angle from the tail side if the entire vehicle 100 fits in the frame image, or the optical axis may be substantially perpendicular to the road surface from above. The angle may be a vertical angle, or an angle in which the optical axis is in the width direction of the road (the vehicle width direction of the traveling vehicle 100) from the road side.

The axle load measuring device 1A associates the vehicle 100 captured in the frame image of the camera 8 with the vehicle 100 traveling in the measurement section (the vehicle 100 measuring the axle load). Further, the axle load measuring device 1 processes the frame image of the camera 8 and estimates the type of the vehicle 100 being imaged. The type of the vehicle 100 mentioned here is classified by the weight of the vehicle 100 (hereinafter, sometimes simply referred to as vehicle weight). For example, the types of the vehicle 100 include a first type vehicle (for example, a passenger vehicle), a second type vehicle (for example, a small/medium truck), a third type vehicle (for example, a large truck), and a fourth type vehicle (for example, a vehicle). Trailer). In this example, the first type vehicle is the type of the vehicle 100 whose vehicle weight is less than T1t, and the second type vehicle is the type of the vehicle 100 whose vehicle weight is in the range of T1t or more and less than T2t. The third type vehicle is a type of the vehicle 100 having a vehicle weight in the range of T2t or more and less than T3t, and the fourth type vehicle is a type of the vehicle 100 having a vehicle weight of T3t or more. However, T1<T2<T3.

In addition, the classification by vehicle type is not limited to the above-described four classifications, and may be three or less classifications or five or more classifications.

Since the axle load sensors 2 to 4 and the vehicle detection sensors 6 and 7 are the same as those in the above-mentioned example, description thereof will be omitted here.

FIG. 9 is a block diagram showing a configuration of a main part of an axial load measuring device 1A according to this another example. The axial load measuring device 1A according to this example differs from the axial load measuring device 1 described above in that the axial load measuring device 1A includes an image input unit 16 and that the control unit 11 includes a vehicle type estimating unit 25. .. The camera 8 is connected to the image input unit 16, and the frame image captured by the camera 8 is input. The image input unit 16 has an image memory (not shown) that temporarily stores the frame image input from the camera 8.

The vehicle type estimation unit 25 included in the control unit 11 processes the frame image input to the image input unit 16 and estimates the type of the vehicle 100 captured in this frame image. The vehicle type estimation unit 25 estimates the type of the vehicle 100 based on the outer shape of the vehicle 100, the size of the vehicle 100 (vehicle length (total length), vehicle height (overall height), vehicle width (overall width)), and the like.

Further, in the axle load measuring device 1A according to this example, the type of the vehicle 100 estimated by the vehicle type estimating unit 25 by the measurement data generating unit 22 is the measurement data shown in FIG. 3 and the calculation data shown in FIG. Correspond to. For example, the vehicle ID includes a code indicating the type of the corresponding vehicle 100. In other words, the measurement data generator 22 generates a vehicle ID including a code indicating the type of the vehicle 100. For example, the lower digits of the vehicle ID are codes indicating the type of vehicle 100.

The method of associating the type of the vehicle 100 with the measurement data and the calculation data is not limited to the method of including the vehicle ID in the vehicle ID described above, and may be another method.

In addition, the axle load measuring device 1A according to this example stores not only the difference threshold value described in the above example, but also the vehicle upper limit threshold value and the vehicle lower limit threshold value in the memory of the control unit 11. Further, in this example, the difference threshold value, the vehicle upper limit threshold value, and the vehicle lower limit threshold value are stored for each type of the vehicle 100. Specifically, as shown in FIG. 10, threshold value data in which a difference threshold value, a vehicle upper limit threshold value, and a vehicle lower limit threshold value are associated with each other for each type of vehicle 100 is stored in the memory of the control unit 11. In the example shown in FIG. 10, ta1<tb1<tc1<td1, ta2<tb2<tc2<td2, and ta3<tb3<tc3<td4.

The vehicle upper limit threshold and the vehicle lower limit threshold stored as the threshold data are for the vehicle 100 of that type, and are not the axle load upper limit threshold and the axle load lower limit threshold in the present invention. The upper limit threshold of axle load referred to in the present invention is a value obtained by dividing the vehicle upper limit threshold corresponding to the type of vehicle 100 by the number of axles of the vehicle 100. Similarly, the lower limit threshold value of the axle load referred to in the present invention is a value obtained by dividing the vehicle lower limit threshold value corresponding to the type of the vehicle 100 by the number of axles of the vehicle 100. As described above, the upper limit threshold value of the axle load and the lower limit threshold value of the axle load according to the present invention have different values depending on the number of axles even in the same type of vehicle 100.

Further, the axial load measuring device 1A according to this example is provided with a storage area for a counting counter, which will be described later, in the memory of the control unit 11, instead of the difference exceeding counter in the above example.

Next, the operation of the axial load measuring device 1A according to this example will be described. The axle load measuring device 1A according to this example also performs measurement processing and measurement accuracy diagnosis processing. First, the measurement process of the axial load measuring device 1A according to this example will be described. FIG. 11 is a flowchart showing the measurement process of the axle load measuring device 1A according to this example.

When the axle load measuring device 1A detects the entry of the vehicle 100 into the measurement section (s31), it starts to store the wheel load data of the wheel load sensors 2R to 4R and 2L to 4L (s32). When the axle load measuring device 1A detects the exit of the vehicle 100 from the measurement section (s33), the axle load measuring device 1A ends the storage of the wheel load data of the wheel load sensors 2R to 4R and 2L to 4L (s34). The axle load measuring device 1A calculates a wheel load measurement value for each axle of the vehicle 100 for each of the wheel load sensors 2R to 4R and 2L to 4L (s35). The steps s31 to s35 are the same as the steps s1 to s5 of the axial load measuring device 1 described above.

The axle load measuring device 1A is a frame image captured by the camera 8 after this point of time when the entry of the vehicle 100 into the measurement section is detected as a reference, and the entry into the measurement section is detected this time. The frame image in which the entire vehicle 100 is captured is determined as the processing target frame image. The vehicle type estimation unit 25 estimates the type of the vehicle 100 captured in the processing target frame image (s36).

In addition, in FIG. 5, the process of s36 is supposed to be performed after the process of s35, but the generation of the measurement data is performed in s37 from the time when the entry of the vehicle 100 into the measurement section is detected in s31. It may be executed at any timing until it is executed.

The axle load measuring device 1A generates measurement data in s37 and calculation data in s38. The process of s37 and s38 is substantially the same as the process of s6 and s7 described above, but the process of associating the generated measurement data and calculated data with the type of the vehicle 100 estimated in s36 is performed. There is a difference.

The axial load measuring device 1A stores the measurement data generated in s37 and the calculation data generated in s38 in the measurement value DB 14 (s39), and returns to s31.

As described above, in the measurement processing executed by the axle load measuring device 1A according to this example, the frame image captured by the camera 8 is processed to estimate the type of the vehicle 100 traveling in the measurement section, and the vehicle 100. This is different from the measurement processing performed by the axial load measuring device 1 in the above-described example in that the type of is associated with the measurement data and the calculation data.

Next, the measurement accuracy diagnosis process of the axial load measuring device 1A according to this example will be described. FIG. 12 is a flowchart showing the measurement accuracy diagnosis process of the axle load measuring device according to this example.

When the axle load measuring device 1A determines that it is the diagnostic timing, the axle load measuring device 1A determines the target vehicle group (s41, s42). The process of s41 and s42 is the same as the process of s11 and s12 described above. When the axle load measuring device 1A determines the target vehicle group in s42, the axle load measuring device 1A executes the aggregation process (s43).

FIG. 13 is a flowchart showing the aggregation processing of the axle load measuring device according to this example. In the axle load measuring device 1A according to this example, a memory area that functions as a counting counter shown in FIG. 14 is provided in the memory of the control unit 11. In this counting counter, the number of axles whose measured value exceeds the upper threshold of axle load (Ca1, Ca2, Ca3 shown in FIG. 14) for each axle load sensor 2-4, and each axle load sensor 2-4 , The number of axles whose measured value is less than or equal to the lower limit threshold of axle load (Cb1, Cb2, Cb3 shown in FIG. 14), and the number of axles exceeding the difference threshold (C shown in FIG. 14) are counted.

Further, in the axial load measuring device 1A according to this example, as in the above-described axial load measuring device 1, the memory of the control unit 11 is provided with a storage area which functions as a determination axis number counter.

The difference calculation unit 23 determines the axle to be determined (s51). The difference calculation unit 23 calculates a difference between the maximum value and the minimum value of the axle loads measured by the axle load sensors 2 to 4 with respect to the determination target axle determined in s51 (s52). s51 is the same process as s21 described above, and s52 is the same process as s22 described above.

The determination unit 24 sets a difference threshold, an upper limit threshold of axle load, and a lower limit threshold of axle load according to the type of the vehicle 100 on the determination target axle determined in s51 (s53). The determination unit 24 refers to the threshold data shown in FIG. 10 and sets a difference threshold, an upper limit threshold of the axial load, and a lower threshold of the axial load. Specifically, the determination unit 24 sets, in the threshold data, the difference threshold associated with the vehicle 100 of the relevant type as the difference threshold. In addition, the determination unit 24 divides the vehicle upper limit threshold value of the vehicle 100 of the corresponding type registered in the threshold value data by the number of axles (the number of axles) of the vehicle 100 corresponding to the axle to be determined this time. , Is set as the upper limit threshold of the axial load. The determination unit 24 also divides the vehicle lower limit threshold value of the vehicle 100 of the corresponding type registered in the threshold value data by the number of axles (the number of axles) of the vehicle 100 corresponding to the axle to be determined this time. , And set as the lower threshold of the axial load. In this example, it is assumed that the weight of the vehicle 100 is evenly applied to the axle of the vehicle 100 (actually, it is not equal), and the upper limit threshold of the axle load and the lower limit threshold of the axle load are set in s53. ..

If the difference calculated in s52 exceeds the difference threshold set in s53, the determination unit 24 increments the difference excess count value C of the counting counter (s54, s55). If the difference calculated in s52 does not exceed the difference threshold set in s53, the determination unit 24 does not increment the difference excess count value C of the counting counter in s55.

In addition, the determination unit 24, if there is the axle load sensor 2 to 4 whose measured value exceeds the upper limit threshold of the axle load set in s53, count values Ca1 and Ca2 that exceed the upper limit threshold of the corresponding axle load sensors 2 to 4. , Ca3 are incremented (s56, s57). If there is no one of the axle load sensors 2 to 4 whose measured value exceeds the axle weight upper limit threshold set in s53, the determination unit 24 determines that the axle weight sensors 2 to 4 exceed the upper threshold threshold count values Ca1, Ca2, Ca3. Is not incremented.

In addition, if there is an axle load sensor 2 to 4 whose measured value is equal to or less than the lower limit threshold value of the axle weight set in s53, the determination unit 24 counts values Cb1 and Cb2 below the lower limit threshold value of the corresponding axle load sensors 2 to 4, Cb3 is incremented (s58, s59). If there is no shaft load sensor 2 to 4 whose measured value is equal to or lower than the lower limit threshold value of the axial load set in s53, the determination unit 24 sets the count values Cb1, Cb2, and Cb3 below the lower limit threshold value of the shaft load sensors 2 to 4. Do not increment.

The determination unit 24 increments the count value of the determination axis number counter (s60). Further, the various count values counted by the counting counter and the count value of the determination axis number counted by the determination axis number counter are reset when it is determined at s41 that the diagnostic timing is reached. The axle load measuring device 1 determines the presence or absence of an unprocessed axle (s61), and if there is an unprocessed axle, returns to s51. When the axle load measuring device 1 determines in s61 that there is no unprocessed axle, this aggregation processing ends.

As described above, in the totaling process shown in FIG. 13, the number of axles determined as the determination target in s51 is counted as the count value of the determination axis number counter. In addition, the number of axles whose difference between the maximum value and the minimum value of the axle load measured by the axle load sensors 2 to 4 exceeds the difference threshold is counted as the difference difference count value C of the counting counter. To do. For each of the axle load sensors 2 to 4, the number of axles whose measured value exceeds the upper limit threshold of axle load is counted as the upper limit threshold excess count values Ca1, Ca2, Ca3 of the counting counter. Further, for each of the axle load sensors 2 to 4, the number of axles whose measured value is equal to or less than the lower limit threshold value of the axle load is counted as the lower limit threshold value or less count value Cb1, Cb2, Cb3 of the counting counter.

Furthermore, as described above, the axle load measuring device 1 according to this example sets the difference threshold according to the type of the vehicle 100, and sets the upper limit threshold of the axle load and the lower limit threshold of the axle load as the type of the vehicle 100. , Is set according to the number of axes of the vehicle 100. Therefore, a difference threshold value, an upper limit threshold value of axle load, and a lower limit threshold value of axle load can be set for the axle determined as the determination target according to the type of the vehicle 100.

Returning to FIG. 12, the determination unit 24 executes the determination process when the aggregation process in s43 is completed (s44). FIG. 15 is a flowchart showing the determination process in s44. The determination unit 24 calculates an upper limit threshold excess ratio for each of the axle load sensors 2 to 4 (s71). In s71, a value obtained by dividing the count values Ca1, Ca2, Ca3 exceeding the upper limit threshold of the counting counter by the count value X of the determination axis number counter is calculated. If the ratio calculated in s71 includes the axial load sensors 2 to 4 that exceed the first ratio, the determination unit 24 determines that the measurement accuracy of the axial load sensors 2 to 4 is not appropriate (s72). ..

In addition, the determination unit 24 calculates the ratio equal to or lower than the lower limit threshold for each of the axle load sensors 2 to 4 (s73). In s73, a value obtained by dividing the count values Cb1, Cb2, Cb3 equal to or lower than the lower limit threshold of the counting counter by the count value X of the determination axis number counter is calculated. If the ratio calculated in s73 includes the axial load sensors 2 to 4 that exceed the second ratio, the determination unit 24 determines that the measurement accuracy of the axial load sensors 2 to 4 is not appropriate (s74). ..

The first ratio and the second ratio may have the same value or different values.

The determination unit 24 determines the presence/absence of the axle load sensors 2 to 4 determined in s72 or s74 that the measurement accuracy is not appropriate (s75). The determination unit 24 ends this process if there is the axial load sensor 2 to 4 that is determined in s72 or s74 that the measurement accuracy is not appropriate. In this case, the determination unit 24 obtains a determination result that specifies the axle load sensors 2 to 4 whose measurement accuracy is not appropriate.

In addition, if there is no axle load sensor 2 to 4 that is determined to have an incorrect measurement accuracy in s72 or s74, the determination unit 24 calculates the difference threshold excess ratio (s76). In s76, a value obtained by dividing the count value C exceeding the difference of the counting counter by the count value X of the determination axis number counter is calculated. If the difference threshold excess ratio calculated in s76 is equal to or less than the appropriate ratio, the determination unit 24 determines that the measurement accuracy of the axle load sensors 2 to 4 is appropriate (s77, s78), and ends this processing. If the difference threshold excess ratio calculated in s76 is not less than or equal to the proper ratio, the determination unit 24 determines that the measurement accuracy of the axle load sensors 2 to 4 is not appropriate (s77, s79), and ends this processing. In s79, the determination unit 24 obtains a determination result in which the axle load sensors 2 to 4 whose measurement accuracy is not appropriate are not specified.

Returning to FIG. 12, when the determination processing related to s44 is completed, the axial load measuring device 1A outputs the determination result by the determination unit 24 from the output unit 15 to the higher-level device (s45), and ends this processing.

The first ratio, the second ratio, and the proper ratio of the axial load measuring device 1A according to this example are stored in the memory of the control unit 11 as in the axial load measuring device 1 of the above-described example. In addition, the first ratio, the second ratio, and the appropriate ratio are set in any one of the axle load sensors 2 to 4 due to external factors such as vibration of the vehicle 100 and noise as described in the above example. In order to prevent erroneous determination that measurement accuracy is not proper due to an axle whose weight has not been properly measured, it is preferable to set the weight according to the number of axles to be processed in the above processing. For example, it is preferable to set a relatively large value when the number of axles to be processed is several (for example, 2 to 5), and to set a relatively small value when the number of axles to be processed exceeds several hundred. .

As described above, the axle load measuring device 1A according to this example sets the difference threshold according to the type of the vehicle 100. Therefore, the vehicle can be used to determine whether or not the measurement accuracy of the axle load sensors 2 to 4 is appropriate. It is possible to suppress the influence of the difference in 100 types (vehicle weight).

Further, since the axial load measuring device 1A according to this example uses the upper limit threshold of the axial load and the lower limit threshold of the axial load to determine whether or not the measuring precision of the axial load sensors 2 to 4 is appropriate, the measuring precision It is also possible to specify the axial load sensors 2 to 4 whose values are not appropriate. In addition, all the axial load sensors 2 to 4 are in a state in which the measurement value is reduced to the same degree in the true value and the measurement accuracy is not appropriate, or the measurement value is increased in the true value. Even if the measurement accuracy decreases to the same degree as above, and the measurement accuracy of the shaft load sensors 2 to 4 is not appropriate due to the use of the upper limit threshold value of the shaft load and the lower limit threshold value of the shaft load. You can judge.

The axle load measuring device 1A performs the above-described determination process using the axial load upper limit threshold (s71 and s72) or the determination process using the axial load lower limit threshold (s73 and s74). The configuration may be such that at least one of the above is not executed. For example, when the process related to the determination using the upper limit of axle load is not performed, the upper limit threshold of axle load does not have to be calculated in s53 described above. Further, it is not necessary to perform the processing related to s56, s57, s71, and s72. Further, when the process related to the determination using the lower limit of the axial load is not performed, it is not necessary to calculate the lower limit threshold of the axial load in s53 described above. Further, it is not necessary to perform the processing related to s58, s59, s73, and s74.

In the above example, the frame image captured by the camera 8 is processed to estimate the type of the vehicle 100. However, the type of the vehicle 100 is estimated based on the number of axles (the number of axles) and the inter-axis distance. You may. With this configuration, the camera 8 can be eliminated and the image processing in the control unit 11 is not required, so that the processing load can be significantly reduced.

Further, in the above example, the example in which the three axial load sensors 2 to 4 are arranged in the traveling direction of the vehicle 100 has been described, but the number of axial load sensors arranged in the traveling direction of the vehicle 100 is two or more. Any number can be used as long as it is.

It should be noted that the order of the steps in the flowcharts described in the explanations of all the above examples is merely an example, and may be interchanged within a possible range.

The present invention is not limited to the above embodiments as they are, and can be embodied by modifying the constituent elements within a range not departing from the gist of the invention in an implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements of different embodiments may be combined appropriately.

Furthermore, the correspondence relationship between the configuration according to the present invention and the configuration according to the above-described embodiment can be described as the following supplementary notes.
<Appendix>
An axle load sensor connection portion (12) to which measurement signals of a plurality of axle load sensors (2 to 4) arranged side by side in the traveling direction of the vehicle (100) are input;
A difference calculation unit (23) that calculates a difference between the maximum value and the minimum value of the measurement values corresponding to the measurement signals input from the plurality of axle load sensors (2 to 4) for the same axle;
An axle load measuring device (1) comprising: a determination unit (24) that determines whether or not the magnitude of the difference calculated by the difference calculation unit (23) exceeds a difference threshold.

1, 1A... Axle load measuring devices 2-4... Axle load sensors 2R-4R, 2L-4L... Wheel load sensors 6, 7... Vehicle detection sensor 8... Camera 11... Control unit 12... Axle load sensor connection part 13... Loop Coil sensor connection 14... DB
14... Measurement value database (measurement value DB)
15... Output unit 16... Image input unit 21... Measurement value calculation unit 22... Measurement data generation unit 23... Difference calculation unit 24... Judgment unit 25... Vehicle type estimation unit 100... Vehicle

Claims (9)

An axle load sensor connection portion into which measurement signals of a plurality of axle load sensors arranged side by side in the traveling direction of the vehicle are input,
For the same axle, a maximum value of the measurement value according to the measurement signal input from the plurality of axle load sensors, a difference calculation unit for calculating the difference between the minimum value,
A shaft load measuring device, comprising: a determination unit that determines whether or not the magnitude of the difference calculated by the difference calculation unit exceeds a difference threshold. A vehicle type estimation unit that estimates the type of the vehicle,
The axle load measuring device according to claim 1, further comprising: a threshold setting unit that sets the difference threshold according to the type of the vehicle estimated by the vehicle type estimating unit. The threshold setting unit sets a lower limit threshold of axle load according to the type of the vehicle estimated by the vehicle type estimating unit,
The axial load measuring device according to claim 2, wherein the determination unit also determines, for each of the axial load sensors, whether or not a measurement value according to the input measurement signal exceeds the lower limit threshold value. The threshold setting unit sets an upper limit threshold of axle load according to the type of the vehicle estimated by the vehicle type estimating unit,
The axial load measuring device according to claim 2, wherein the determination unit also determines, for each of the axial load sensors, whether or not a measurement value according to the input measurement signal exceeds the upper limit threshold value. .. The axle load measuring device according to claim 2, wherein the vehicle type estimation unit processes a frame image of the vehicle captured by an image capturing device and estimates the type of the vehicle. The axle load measuring device according to claim 1, wherein the axle load sensor is a pair of wheel weight sensors arranged in a vehicle width direction. The axle load measuring device according to claim 1, further comprising a vehicle weight calculator that calculates the weight of the vehicle by using measurement signals of the plurality of axle load sensors when the vehicle is traveling. A plurality of axle load sensors arranged side by side in the traveling direction of the vehicle, the maximum value of the measurement value according to the measurement signal measured for the same axle, a difference calculation step of calculating the difference between the minimum value,
A determination step of determining whether or not the magnitude of the difference calculated in the difference calculation step exceeds a difference threshold value. A plurality of axle load sensors arranged side by side in the traveling direction of the vehicle, the maximum value of the measurement value according to the measurement signal measured for the same axle, a difference calculation step of calculating the difference between the minimum value,
And a determination step of determining whether or not the magnitude of the difference calculated in the difference calculation step exceeds a difference threshold value.

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