JPS60108717A - Vehicle-weight measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the weight of a vehicle required for receiving a toll, by providing a vehicle judging means, a speed detecting means, an axle-load detecting means, a pulse-width detecting means, a maximum-value detecting means, a correcting-factor keeping means, and a computing means. CONSTITUTION:A vehicle judging means (a) comprises a vehicle detector 18 and a vehicle judging circuit 19. A speed detecting means (b) comprises a speedometer 16 and a speed detecting circuit 17. An axle-load detecting means (c) comprises an axle-load detector 11. A pulse-width detecting means comprises a pulse- width detecting device 15. A maximum-value detecting means comprises a maximum-value detecting circuit 14. A correction-factor keeping means comprises a correcting circuit 20, which keeps the correction factor of the weight of a vehicle based on a vehicle speed obtained beforehand and the pulse width of the output signal of the axle-load detecting means. A computing means comprises a computing circuit 21, which corrects the maximum value based on the correcting factor corresponding to the detected speed and the detected pulse width and obtains the vehicle weight. The fluctuation of the axle load due to the vibration and passing pattern of the running vehicle is corrected, and the correct weight can be obtained positively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle weight measuring device used in a toll collection system on a toll road where tolls are determined by taking into account the heavy traffic of passing vehicles.

On toll roads where tolls are collected according to the weight of the vehicle, it is necessary to measure the type of vehicle.As a device for this purpose, there is a vehicle weight measuring device having a configuration as shown in FIGS. 1 and 2. FIG. 1 is a perspective view showing the system layout, and FIG. 2 is a plan view thereof. In the figure, WY represents a vehicle passageway. In addition, Id is an island on both sides of this traffic road WY, and an axle load detector 1 is installed on the road surface across the traffic road WY. 11, and is constructed by arranging four strain gauge type load cells 2 side by side inside the burial outer frame 1a, and providing a loading plate 3 for receiving the load on top of the strain gauge type load cells 2. The load cells 2 exhibit a change in resistance value in accordance with the load when they receive a load, and are placed one at each of the four corners of the loading plate 3.
When the wheel 8 straddles 9 steps on the loading plate 3, the load is applied to the strain gauge type load cell 2, thereby detecting the load. Reference numerals 4 and 5 denote a light emitter and a light receiver, which are provided facing each other on the island Id at the location where the axle load detector 1 is disposed, and the optical path of the light emitters and receivers 4 and 5 is interrupted by a passing vehicle 7. Especially the axle load detector 1
It is detected that the passing vehicle 7 has approached the position.

A speedometer 6 detects the speed of the vehicle 7.

As shown in the figure, the @load detector 1 of the axle load measuring device is buried in the road surface, and the four strain gauge type load cells 2 of the axle load detector 1 are arranged to form a Wheatstone bridge. When the wheels of the vehicle are placed on the loading plate 3, the load of the axle is applied to each ≠−≠ load cell 2 under the loading plate 3, and their resistance values change, resulting in the balance of the Wheatstone bridge. As a result of the change in the axle weight, it is converted into an electrical signal corresponding to the axle weight, and in the case of a two-axle vehicle, a waveform as shown in FIG. 3 is detected during normal driving. As a result, P, m,
The maximum axle load value of the front wheel and rear wheel and the pulse width T, , T as shown by P2m.

is detected.

Figure 4 is a cross-section showing the relationship between the length of the tire contact surface and the length of the axle load detector, and the tire position where the maximum axle load value is detected when the tires of a normally running vehicle pass over the axle load detector. In the diagram, 10 is the tire.

t is the length of the tire contact surface, L is the vehicle running length of the axle load detector, and the same parts as in FIG. 1 are indicated by the same symbols.

FIG. 4 shows that the tire 10 that entered from the right side increases the axle load value shown in FIG. 3, and has come close to generating the axle load peak value P8m, p, and m. The vehicle traveling length of this axle load detector 10 is longer than the tire contact surface length t, and its size depends on the sensitivity of the strain gauge type load cell 2, but it depends on the speed of the traveling vehicle 7, the tire shape, and the axle load detector. Although it varies depending on the buried state, if the strain gauge type load cell 2 is highly sensitive, it will be 40 mg ~ under normal usage conditions.
100m5+ TItT! The pulse width is shown in . Also, superimposed on the ideal (true value) axis load waveform shown by the dotted line in Figure 3, P,rn-PIt) or (P2m-Pzt)
) This error is generally larger as the axle load detector has better responsiveness as a weighing scale, making it difficult to measure the weight of a running vehicle. The harmful imaging component that causes the error difference of the running vehicle is caused by vibrations of the vehicle itself due to unevenness of the road surface, how the vehicle is braked, etc., and is superimposed on the true axle load Wt and fluctuates. However, the axle load W detected by the axle load detector is expanded into a Fourier series, and the correct axle load Wt can be estimated by observing the axle load waveform and repeatedly performing vibration analysis of the running vehicle. I can do it.

However, a practical problem is that waveforms as shown in FIG. 5 frequently occur. This is caused by jumps in the vehicle axle wheels and vehicle slippage due to rain or ice.During such special driving, the detected maximum axle load values p, t/, p2t/, the pulse width T,'', T,' is a small value. That is, PHt'
<PHt, P2t'< Pzt.

T+'<T+tTz'<T2 holds true.

FIG. 6 shows an example of tire positions in the case of an axle load waveform as shown in FIG. 5, and the reference numerals are the same as in FIG. 4.

For this reason, in order to remove the waveform during special driving as shown in Figure 5, conventional methods have been to increase the vehicle running length as shown in Figure 4 by several meters, or to install multiple axle load detectors at regular intervals. It was installed with. However, these methods (1) require a large number of axle load detectors, which are long and burdensome in terms of burial costs and maintenance;

(2) Even if the axle load can be set at 61 during normal driving, during special driving, for example, at a speed that exceeds the performance of the axle load detector, the upper limit is 30.
Even if it passes at 40bn/h for ht/h, the weight value will be output without correction.

These drawbacks have made it difficult to put a weight-based toll collection system into practical use.

The present invention eliminates the drawbacks of the conventional weight measuring device, corrects the influence of the passing form on the axle load detection section of the traveling vehicle, and makes it possible to accurately measure the vehicle weight necessary for toll collection. Also, the front, rear, forward, leading vehicle and rear of the vehicle necessary for toll collection.

The present invention will be described in detail below based on the drawings.

FIG. 7 is a correction curve used in the present invention, where the speed vl +
The relationship between V2 *VS sV4 is v4. > vs ) v
2) It is vl.

The axle load W calculated by the Fourier series by superimposing the vehicle vibration component on the true axle load Wt varies depending on the form of the vehicle passing through the axle load detector, but the accuracy required for toll collection (
For example, from the point of view of practical problems, the trend value is determined by two factors: the passing speed and the pulse width obtained at that time. That is, (1) Considering the stationary state of speed v=O, the higher the passing speed, the more the vehicle vibration component is superimposed and the detected axle load W becomes larger.

(2) Pulse width is T in Figure 7. When the Knoll width above is obtained, the strain gauge type load cell 2 can be considered to have a sufficient response as shown in Fig. 3, and when the pulse width is less than To, the passage form as shown in Fig. 5 can be considered. In this case, the strain gauge type load cell 2 has an insufficient response, but the detected axle load W is proportional to its special pulse width. If we collect experimental data according to the passing mode by driving in various configurations using vehicles with known
A correction curve as shown in the figure is obtained.

For example, in Figure 7, the unit coefficient is the weight coefficient d, which is the true axle load Wt.
The ratio of the detected axle load W to the detected axle load W, that is, W/Wt.

Also, in practice, it is normal to pass the weight detector at less than 30Jea/h, but if you pass at 80Jea/h, or if you brake suddenly just before the weight detector and intentionally cause the vehicle to jump. In this case, the obtained pulse width is small, for example, the pulse width is less than Tc in FIG.

This type of passage is rare in practical use, and in such cases, an alarm signal etc. is output and manual intervention is required.Less than 1, less than 3 + less than 8, less than 12.

If the setting button of 12 tons or more is pushed down visually, there is no problem in terms of toll collection.

Therefore, if the correction curve shown in FIG. 7 is obtained, it is possible to approximate the true axle load.

FIG. 8 is a block diagram showing the configuration of an embodiment of the entire weight measuring device of the present invention, and 11 is an axle load detector similar to the axle load detector 1 shown in FIG. 1, which has a Wheatstone bridge;
12 is an amplifier for amplifying the signal from the axle load detector 11;
3 is an A/D converter for A/D converting the signal from this amplifier 12.
]) converter, 14 is a maximum value detection circuit that accumulates data signals from this A/l) converter 13 in time series and detects the maximum value expanded into a Fourier series; 15 is a signal from the amplifier 12; 1 with a pulse width detection circuit that detects the pulse width.
1.12, 13° J4, 15 constitute an axle load detection device. 16 is a speedometer that detects the speed of the vehicle, and 17 is a signal from this speedometer 16 for a certain period of time (for example, 10m5, etc.)
These 16.77 constitute a speed detection device, which is a speed detection circuit that digitizes and outputs each time. Reference numeral 18 denotes a vehicle detection unit, and 19 a vehicle discrimination circuit, which is formed by the light emitter and receiver of the vehicle detection unit 18 for vehicle detection, which is arranged opposite to each other on an island through a vehicle passageway. These circuits 18 and 19 constitute a vehicle discrimination device, including a circuit for shielding the optical path and outputting a pulse signal indicating that a vehicle is passing through. 2
0 is a correction circuit that stores the experimentally determined correction curve shown in FIG.
7. Output signal of pulse width detection circuit 15 and speed detection circuit 1
Corresponding to the output signals of 7 and 7, data obtained by the correction circuit 20 is used to correct the axle weight by calculation to obtain an approximate true value of the axle weight, and while the vehicle discrimination circuit 19 is in the ON state, For each axle wheel, the axle weight is integrated and the weight of the vehicle is output, or there is a situation where the calculation is impossible (over speed).

This is an arithmetic circuit for weight calculation that outputs an alarm signal in case of an extremely small pulse width) or a failure of equipment, and 20.21 constitutes a weight calculation device.

Next, the operation of this device having the above configuration will be explained. This device has an axle load detector 11. The light emitter/receiver of the vehicle detection unit 18 and the speedometer 16 are arranged in the same manner as in FIGS. 1 and 2.

In this device, when a vehicle enters and the front end of the vehicle interrupts the optical path formed by the light emitter/receiver of the vehicle detection unit 18, the vehicle detection unit 18 detects the vehicle due to this interruption. , gives a detection output to the vehicle discrimination circuit 19.

Therefore, the vehicle discrimination circuit 19 detects a vehicle while the vehicle detection section 18 is detecting a vehicle, that is, while the optical path continues to be interrupted.
A pulse signal (for example, an It HII level signal) indicating that the vehicle is passing is outputted and given to the arithmetic circuit 21. On the other hand, a speedometer 16 is provided near the light emitting/receiving device installation position of the vehicle detection unit 18. This speedometer 16 detects the speed of the vehicle near the position of the light projector/receiver of the vehicle detection section 18 and sends its detection output to the speed detection circuit 17 . Then, this speed detection circuit 17 receives this detection output and the speed data,
This is given to the arithmetic circuit 21.

Furthermore, when the tires of the vehicle press the loading plate of the axle load detector 11, an output is generated from the load cell of the axle load detector 1 forming a Wheatstone bridge in accordance with the amount of the applied electric current, and this output is amplified by the amplifier 12. and sent to the pulse width detection circuit 15 and A/D converter 13.

Accordingly, the pulse width detection circuit 15 detects the pulse width of the signal output from the axle load detector 1 in accordance with the form in which the vehicle presses the loading plate, and sends it to the arithmetic circuit 21 as data.

Further, the A/l) converter 13 A/D converts a signal corresponding to the axle load detected by the axle load detector 1 to digitize it, and then supplies the signal to the maximum value detection circuit 14 .

Then, the maximum value detection circuit 14 receives this digitized data signal, stores it in time series, expands it into a Fourier series, detects the maximum value, and supplies it to the arithmetic circuit 2.

The maximum value is detected here because when the axle passes over the loading plate of the axle load detector 11, the output does not reflect the correct axle load until the position of the tire reaches the center of the loading plate, so it is a low value. Therefore, by detecting the maximum value, an output reflecting the correct axle load can be obtained. Then, while the vehicle discrimination circuit 19 is in the on state, the arithmetic circuit 2 calculates the speed of the vehicle based on the detected pulse width of the pulse width detection circuit 15 and the vehicle speed data outputted from the speed detection circuit 17 at every predetermined time interval, as shown in FIG. The correction circuit 2 stores correction data in advance due to the following relationship.
The data corresponding to 0 is read out, and the output data of the maximum value detection circuit 14 is corrected using this correction data. The corrected data is then stored as axle weight detection data until the ail passing vehicle completes passage. In other words, in the case of a two-axle vehicle, the above-mentioned detection data for the two axles of the front axle and the rear axle are obtained sequentially in response to the passing of the axle load detector 11, and independently of the axle load. The detection data sequentially obtained during the optical path interruption of the device is accumulated (integrated), and when the optical path interruption is resolved, the accumulated detection data is output as the IT data of the passing vehicle.

This allows accurate vehicle weight measurement without being affected by vehicle traffic patterns. After the output of the weight data is finished, the system is reset until the next vehicle interrupts the optical path of the vehicle detection section 18.

In addition, the arithmetic circuit 21 is operated when calculation becomes impossible due to overspeed of the vehicle or extremely small pulse width, or due to axle load fluctuations due to vibrations such as failure of equipment composing the system and Ilη due to the passing pattern. It is possible to compensate for heavy weight fluctuations to ensure that the correct weight value required for toll collection is obtained, and to issue an alarm when weight measurement is impossible or when there is a mechanical failure, prompting manual setting. This enables toll collection by

It should be noted that when the vehicle is moving forward or backward, the speed detection circuit 17 outputs the previous signal at fixed time intervals, and when the vehicle is moving forward, the signal from the pulse width detection circuit 15 is detected after the vehicle speed signal is generated. , in the case of reverse movement, the speed signal and the pulse width signal are simultaneous, so the speed detection circuit 17 and the pulse width detection circuit 1
One judgment can be made at the signal output timing with 5. It can also be easily surmised that it will be possible to make a total of 711 points of passing weight.

Further, the present invention is not limited to the embodiments shown in the above-mentioned example, and can be implemented with appropriate modifications within the scope of the gist thereof. i.
do not have.

As described in detail above, the present invention includes a vehicle discriminating means that generates a vehicle detection output while the vehicle passes a predetermined position on a vehicle passageway, a speed detecting means that detects the speed of the vehicle when passing the predetermined position, Axle load detection means is installed on the road surface at the above-mentioned predetermined position of the vehicle passageway, and generates a signal according to the weight of the wheel in response to the pedal pressure of the wheel.The axle load detection means receives the output signal of the axle load detection means and detects its pulse width. a maximum value detection means for detecting the maximum value of the output signal of the axle load detection means, and a vehicle weight correction based on a predetermined vehicle speed and the pulse width of the output signal of the 1ii1 double inspection lit means. a means for holding a coefficient; Corrected with this correction coefficient, 1 (
(1st layer, ・: Consists of a calculation means that obtains data for vehicle type 1 by integrating the i!11 weighted values for each song, and detects when the vehicle reaches a predetermined position and The vehicle generates a detection output until it completes passing through this position, and also detects the speed of the vehicle when passing this position, and still detects the axle weight detection means installed on the road surface at that position. Obtain the detection output of the heavy vehicle of the passing vehicle, obtain the pulse width and maximum value of the detection output of the axle weight, and calculate the above-mentioned detection among the correction coefficients based on the speed and the pulse width of the vehicle obtained in advance. Obtaining a correction coefficient corresponding to the speed and pulse width, and correcting the maximum value using the correction coefficient as the weight data of the axle;
In addition, since the vehicle weight data is obtained by integrating the weight data of each I axle load sequentially obtained until the completion of the passage, the detected value of the axle load, which changes depending on the driving mode of the vehicle, is It can be corrected according to the vehicle type, and the correct weight of 11 cars can be obtained from this corrected value, so automatic weight measurement is possible when toll roads have a toll system based on vehicle weight. In addition to making it possible to implement a collection system, etc., conventionally, when measuring the axle load of 117 running vehicles, it was attempted to absorb weight fit fluctuations due to vehicle vibration only by heavy stitching, so the weight 4. ■(It used to be large or require multiple units and was inaccurate, but it is small and accurate. The old weighing scale only needs one unit, and since the detection output can be obtained from the shaft bar, information on the number of shafts can be obtained.) It is possible to provide a vehicle weight measuring device having characteristics such as being able to obtain vehicle weights (two-axle vehicles, three-axle If, four-axle vehicles, etc.) and being able to deal with a fee system that also includes the number of axles.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the system layout of the vehicle weight measuring device, Figure 2 is a plan view of Figure 1, and Figure 3 is a diagram showing the system layout of the vehicle weight measuring device.
Axle load waveform when the axle vehicle passes the axle load detector, Figure 4 shows the maximum value detection tire position, tire contact surface, and length of the axle load detector when the vehicle passes over the axle load detector during normal driving. Part 5 is a two-axle vehicle during special running. Figure 7 is an explanatory diagram of the correction curve used in the present invention. Figure 8 is a block diagram of an embodiment of the weight measuring device of the present invention. It is a diagram. 1... Outer frame for burial, 2... Strain gauge type load cell, 3... Loading plate, 4... Emitter, 5... Light receiver, 6... Speed meter, 7... Traveling Vehicle, 8... Front wheels of the running vehicle, 9... Rear wheels of the running vehicle, 10... Tires of the running vehicle, 1... S+ heavy detector, 12... Amplifier, 13... A/D converter, 14... Maximum value detection circuit, 15... Pulse width detection circuit, 16... Speed meter, 17... Speed detection circuit, 18... Vehicle detector, 1
9°°° Vehicle discrimination circuit, 20... Correction circuit, 21...
・Arithmetic circuit. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 2 Marijo

Claims (1)

[Claims] A vehicle determining means that generates a vehicle detection output while the vehicle passes a predetermined position on the vehicle passageway, a speed detection means that detects the speed of the vehicle when passing the predetermined position, and a road surface at the predetermined position on the vehicle passageway. an axle load detection means installed on the shaft and generating a signal according to the weight of the wheel in response to the pedal pressure of the wheel; a pulse width detection means receiving the output signal of the axle load detection means and detecting the pulse width thereof; maximum value detection means for detecting the maximum value of the output signal of the weight detection means; means for holding a vehicle weight correction coefficient based on a predetermined vehicle speed and a pulse width of the output signal of the axle load detection means; While receiving the detection output, the correction coefficient holding means obtains a correction coefficient corresponding to the detected speed and the detected pulse width of the speed detection means, and corrects the maximum value using the correction coefficient to correct the axle load; A vehicle weight measurement device comprising calculation means for obtaining vehicle weight data by integrating axle load values.