JPS6218006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle weight measuring device, and more specifically, the present invention relates to a vehicle weight measuring device, and more particularly, an axle load detecting section and a loop coil type vehicle detecting section are buried in a road such as near the entrance of an expressway. The present invention relates to a vehicle weight measuring device that measures vehicle weight and total weight.

It is installed near expressway entrances, parking lots, or material access roads of civil engineering construction work sites, and automatically measures the axle load, total weight, number of passing vehicles (hereinafter "number of passing vehicles" is simply referred to as "number of vehicles"), etc. In order to measure the axle load of the vehicle, an example shown in FIG. 1 (hereinafter referred to as " It is thought that it is sufficient to arrange them horizontally as shown in the "Reference Example").

That is, in FIG. 1, the axle load detection unit W detects the left and right wheel loads of a passing vehicle, and in order to add them together to obtain the axle load, it uses two loading plates BL that receive the left and right wheel loads separately. , BR and these loading plates
It consists of four strain gauge type load cells LC each supporting BL and BR, and an outer frame F that protects their surroundings. (The number and configuration of the loading plate and load cells may vary depending on the purpose of use other than this example.) On the other hand, the wheel loads of passing vehicles detected by this axle load detection section W are In order to calculate the total vehicle weight by adding up not only the wheel loads of each passing vehicle, but also all axles for each passing vehicle, it is necessary to clearly detect the boundaries between each vehicle. . For this purpose, the loop coil L for vehicle detection, that is, for detecting the number of vehicles, is placed in front of the axle load detection unit W with respect to the approaching vehicle C as shown in the figure La, or on the opposite side of the axle load detection unit W with respect to the incoming vehicle C as shown in the figure Lb. It is buried somewhere. (However, this applies when the direction of vehicle approach is fixed, that is, in the case of one-way traffic; when the direction of vehicle approach is not fixed, both positions, that is, La,
In some cases, loop coils L are buried in both L and B positions. ) In FIG. 1, M is a lane mark displayed on the road surface.

Figure 2 shows a vehicle weight measuring device that the applicant attempted to implement in secret in order to automatically measure the total weight and number of passing vehicles using the detection unit shown as a reference example in Figure 1. FIG. 2 is a block diagram showing a measurement processing circuit system.

In Fig. 2, the axle load detection section W (left side detection section
The left and right wheel loads of the passing vehicle detected by the load cells (bridges) of the WL and the right side detection unit WR are electrically summed in the junction box 11 and amplified as an axle load signal by the amplifier 12. In this case, the high-speed A/D After being converted into a digital quantity by the (analog/digital) converter 13, the maximum value in each axis load waveform is detected by the maximum value detection circuit 14 and stored in the axle load value memory 15 that can store data for at least several axes. At the same time, the axle load value is printed by the printer 17 via the print control circuit 16. This operation is
Since one vehicle has several axes (at least two axes), the same process is repeated as many times as there are axes. The operation of repeatedly storing and printing the axle load value for one vehicle is controlled based on the number detection signal of the loop coil L, which is a vehicle detection section. That is, based on the detection signal of the loop coil L, a signal indicating that one vehicle has passed is sent from the loop coil control circuit 18 to the passing vehicle number counter 19 as an up count signal, and at the same time to the axle load addition circuit 20. Each is given as an axle load addition command to add all the axle load values in the weight value memory 15, and the total weight of the vehicle is calculated and sent to the printer 1 via the print control circuit 16.
7 is printed, and the measurement of the weight of one vehicle and the operation of counting the number of vehicles are completed. The bridge power supply 21 in FIG. 2 is for applying a power supply voltage to the strain gauge (constituting the bridge) in the load cell constituting the axle load detection section W, and is also shown in this block diagram. Needless to say, each circuit is supplied with necessary power from an appropriate power supply section, although not particularly shown.

The operation of the vehicle weight measuring device configured as described above will be explained in detail based on the timing charts shown in FIGS. 3a to 3c.

That is, the axle load waveform WW ₁ due to the front axle and rear axle of a passing vehicle (in this case, a two-axle vehicle, for example) detected by the axle load detection unit W varies in time as shown in FIG. 3a. Two chevron waveforms P ₁ and P ₂ result. On the other hand, the waveforms indicating the presence of a vehicle based on the detection signals of loop coils La and Lb are shown in Fig.
As shown in La ₁ and Lb ₁ shown in c, the signals correspond to two types of on/off, and the loop coil L
The position on the time axis relative to the axle load waveform _WW1 differs depending on the buried position of the axle load waveform WW1. Now, if the loop coil L is buried at the Lb position, the presence of the vehicle (therefore passing) is detected when both the waveform _P1 due to the front axle and the waveform _P2 due to the rear axle of the axle load waveform _WW1 are completed. Since the waveform Lb ₁ shown rises to notify that the vehicle has passed, this fall can be used as an axle load addition command. Furthermore, when the loop coil L is at the La position, the passing vehicle first passes over the loop coil L and then over the axle load detection part W, so the output waveform La ₁ of the loop coil L simply changes. It is not possible to issue an axle load addition command on a downhill trip, so it is necessary to issue an axle load addition command with an appropriate time delay as shown by the broken line in FIG. 3b. However, it may be considered that the essential operation is the same regardless of whether the loop coil L is installed in the La or Lb position, as shown in Figure 3a.
As long as the time conditions shown in -c are ensured, even if the detection section is arranged as shown in FIG. 1, it will operate correctly and will not cause any trouble. The problem arises when such ideal conditions are no longer met; in reality, there is a high possibility that such a situation will occur frequently, and this becomes a factor that reduces the reliability of the vehicle weight measuring device.

Next, the cases in which false detection occurs will be explained. Here, for convenience of explanation, loop coil L
will be explained using the case of the Lb position as an example.

FIG. 4 shows two vehicles C ₁ and C ₂ passing over the loop coil L and the axle load detection unit W in a state in which the two vehicles C 1 and C 2 approach each other. In other words, in this diagram, the preceding vehicle
_C1 passes over the axle load detection section W and further passes through the loop coil L, and its rear portion is about to leave the loop coil L, but has not yet completely separated. In other words, the presence of the vehicle has been detected. on the other hand,
At this time, the front axle of the following vehicle _C2 has already reached the axle load detection section W and is about to descend from the axle load detection section W.

A timing chart of such a case is shown in FIGS. 5a and 5b.

That is, FIG. 5a shows the detection waveform of the axle load detection section W.
WW ₂ , the same figure b shows the detection waveform Lb ₂ of the loop coil L, and before the time t ₁ when the loop coil L detects that the preceding vehicle C ₁ has passed, a waveform Lb 2 in front of the following vehicle C ₂ is detected. The shaft has passed through the axle load detection section W. (P ₃ , P ₂ and _{P 5} are the respective axle weight waveforms of the front axle and rear axle of the preceding vehicle C ₁ and the front axle of the following vehicle C ₂ ).
The axle and the front axle of the following vehicle C ₂ are determined to be the respective axles of the same vehicle (that is, determined to be a 3-axle vehicle), and their total value is regarded as the total weight and printed.
Moreover, for this reason, the rear axle of the following vehicle _C2 is treated as a vehicle with one axle.

Such erroneous detection occurs in various situations depending on the physical dimensions and temporal relationship between the preceding vehicle and the following vehicle, and other factors. For example, the axle load detection waveform WW ₃ and the loop shown in As shown in the vehicle detection waveform Lb ₃ of the coil L, the axle load waveform P ₆ of two two-axle vehicles is
P ₉ (P ₆ and P ₇ are the leading vehicles, P ₈ and P ₉ are the following vehicles) may be considered as one vehicle. (Such erroneous detection is particularly likely to occur, for example, when the distance from the front edge of the loop coils L, Lb to the rear edge of the axle load detection unit W is long.) In this way, the number of axles of passing vehicles,
Overall length of vehicles, vehicle spacing and relative speed when passing;
The frequent occurrence of malfunctions as described above due to a temporary stop or slight backward movement of the preceding vehicle is a major problem for vehicle weight measuring devices.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a vehicle weight measuring device that does not malfunction in practice and has extremely high operational reliability even when vehicles continuously approach and pass. This purpose is to provide a vehicle weight measuring device that measures the axle load and total weight of passing vehicles by embedding an axle load detection section and a loop coil type vehicle detection section on the road. The loop coil type vehicle detection unit is disposed surrounding the axle load detection unit at an appropriate interval and buried in the road, and the loop coil type vehicle detection unit detects passing vehicles. This can be completely achieved by adding the axle loads for all the axles detected by the axle load detecting section while the vehicle is moving to determine the total weight of the passing vehicle.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

Figure 7 shows the embedded state of the loop coil L' as the vehicle weight part and the axle load detection part W' (characteristic in their arrangement relationship) in one embodiment of the present invention, and is similar to Figure 1. Similar parts are given the same reference numerals and detailed explanation thereof will be omitted. That is, as shown in FIG. 7, a loop coil L' is provided so as to surround the axle load detection section W', and the axle load detection section W' is positioned within the loop of the loop coil L'. At this time, the loop coil L' is buried at the same distance from the outer frame F of the axle load detecting section W', for example, about 1 to 30 cm on all four sides. Of course, this loop coil L' and the axle load detection section
The distance between W' and the outer frame F should be determined as appropriate depending on the vehicle running conditions at the installation location, and may be outside the range of 1 to 30 cm, and the distance may vary depending on the direction. In this case, the measurement processing circuit system is the second one.
The configuration is similar to that shown in the figure.

In such a configuration, the width Wg of the axle load detection part W' in the vehicle running direction is usually about 70 cm, so in the above example, the width Wl of the loop coil L' in the same direction is about 70 cm. It will be about 130cm.
Burying the loop coil L' so as to surround the axle load detection part Wl in this way means that when a vehicle approaches, the axle load detection part Wl as shown in Fig. 8a and b
As shown in the axle load detection waveform _WW4 by W′ and the vehicle detection waveform LW by loop coil L′,
Loop coil L' senses the vehicle before axle load detection by W', and when the vehicle passes and exits, all axle load detection by axle load detection part W' is completed. Since a vehicle number detection signal (falling edge of the vehicle detection signal) will be output later from the loop coil L', the operation of the vehicle detection section is extremely ideal. This ensures reliable operation and reduces false detections. Furthermore, by configuring the detection unit in this way, compared to the configuration of the detection unit shown in FIG. 1, the length of the entire detection unit can be made much shorter in the direction of travel of the vehicle, which eliminates the conditions that can cause malfunctions. The probability that there are two running vehicles becomes extremely small,
There is almost no risk of malfunction.

By the way, when we set up the axle load detection unit W' and loop coil L' according to the example above and ran 2- to 5-axle trucks under various conditions, the problem occurred with the device shown in Figure 1. There were no such malfunctions under normal conditions (which could occur on a daily basis).

As mentioned above, the axle load detection part W′ is connected to the loop coil.
Since it is installed within L', the following various advantages arise.

(1) Compared to the case where the axle load detection section and the loop coil are arranged in parallel at a distance, malfunctions during gross weight measurement can be extremely reduced, and sufficient accuracy for practical use can be obtained.

(2) Since the axle load detection unit and the loop coil are buried in approximately the same location, the burial work can be done all at once, and the cost of the burial work can be extremely low.

(3) For the same reason as (2), it occupies less space on the road and maintenance work becomes easier.

(4) For example, if the loop coil is installed in a location such as an uphill slope and there is a possibility that the vehicle in front may move backwards a little, the distance between the loop coil and the axle load detector should be made as small as possible, and the distance between the loop coil and the axle load detector should be kept as small as possible. It is adaptable to usage conditions depending on the installation location, such as by reducing the width Wl of the sensor.

It should be noted that the present invention can be implemented in many modifications other than the above-described embodiments, for example, the distance between the loop coil L' and the axle load detection part W' may be made different between the front side and the rear side in the vehicle running direction. In addition to measuring the axle load, total weight, and number of vehicles for each vehicle, we also measure the wheel load, and by appropriately selecting the burial depth of the loop coil buried under the road surface, we can adjust the detection sensitivity as appropriate. It is also possible to make adjustments.

As explained above, according to the present invention, there is almost no malfunction in practice even when vehicles pass continuously, the operation reliability is extremely high, and the axle load detection section and the loop coil type vehicle detection section It is possible to provide a vehicle weight measuring device that requires less burial work costs, occupies less space on the road, and is easy to maintain.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the arrangement of the detection section in the reference example, and Fig. 2 is a measurement processing circuit system of a vehicle weight measuring device that the applicant attempted to implement privately using the detection section according to the reference example. Block diagram showing the configuration of
Figures a to c are timing charts for explaining the operation, Figures 4, 5 a, b, and 6 a, b.
1 is a diagram for explaining the problem of the detection section arrangement shown in FIG. 1, FIG.
b is a timing chart for explaining the operation of the same embodiment. W'...Axle load detection section, L'...Loop coil.

Claims (1)

[Claims] 1. In a vehicle weight measuring device that measures the axle load and total weight of passing vehicles by embedding an axle load detection section and a loop coil type vehicle detection section on the road, the axle load detection section and the surroundings of this axle load detection section are appropriately The loop coil type vehicle detectors are arranged so as to surround each other with an interval of , and are buried together on the road. 1. A vehicle weight measuring device characterized by being configured to calculate the total weight of the passing vehicle by adding up the axle loads for all the detected axles.