JPH055153B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a vehicle type discrimination device installed, for example, at an entrance to a toll booth on an expressway.

(Prior art and its problems) Conventional devices of this type include ceiling surface height detection devices that detect the height of the vehicle ceiling surface using, for example, ultrasonic detection devices at predetermined intervals in the vehicle traveling direction. and a floor height detection device such as a loop-type detection device that detects the vehicle floor height from voltage changes caused by the vehicle blocking the magnetic field generated by a generator embedded in the road surface. From the vehicle height calculated from the difference in height detected by the above, and the vehicle length calculated based on the time difference between the detection start times of both the detection devices and the vehicle sensing time by either of the detection devices,
As shown in Figure 4, vehicle types such as passenger cars and small cargo, as well as large vehicles such as large cargo and buses, were distinguished.

Furthermore, since the floor height of a bus is generally lower than that of a large cargo vehicle, the type of vehicle between a large cargo cargo and a bus is also determined based on the floor height.

However, in recent years, specifications have diversified, especially for large cargo, and for example, there are vehicle models with floor heights that are almost the same as buses, such as container cars and moving vehicles. Some of them are tall, and in the case of the conventional example having the above-mentioned configuration, there was a drawback that it was not possible to distinguish between these large cargoes and buses, and the discrimination accuracy was reduced.

(Object of the Invention) The present invention was made in view of the above circumstances, and an object of the present invention is to make it possible to clearly distinguish between large cargo and a bus even if the cargo has a low floor height. shall be.

(Structure and Effects of the Invention) In order to achieve the above object, the vehicle type discrimination device of the present invention uses ultrasonic waves that are pulsed intermittently at set times and are reflected by the vehicle ceiling surface. a ceiling surface height detection device that detects the height of the vehicle ceiling surface based on the time difference between the reception time of the ultrasonic wave and a floor surface height detection device that detects the height of the vehicle floor surface provided at a predetermined interval in the direction of vehicle movement; a surface height detection device; a vehicle height detection device that calculates a vehicle height based on a difference in height detected by both of the detection devices; and a speed detection device that calculates a vehicle running speed based on a time difference between detections by both of the detection devices; vehicle length detection means for calculating the longitudinal length of the vehicle based on the speed calculated by the speed detection means and the vehicle sensing time by either one of the detection devices; and detection by the both detection means. a determination means for determining the vehicle type by comparing the combination state of the vehicle height and vehicle length determined with a set combination; and a sensing state by the ceiling surface height detection device;
Compare the detected heights for each pulse to extract the maximum height and minimum height, calculate the difference, and compare the calculated height difference with the set value to determine the unevenness of the set value. and subdivision discrimination means for subdividing vehicle types.

In other words, the discrimination means is used to distinguish between passenger cars, small cargo vehicles, and large vehicles.Furthermore, buses have less unevenness on the vehicle ceiling, while large vehicles have lower ceilings in the driver's cabin and the cargo area behind it. Focusing on the large difference in surface height and the large unevenness of the vehicle ceiling surface, large vehicles are classified into buses and large cargo based on the unevenness of the vehicle ceiling surface height, and as a whole, passenger cars, small cargo, and buses and the vehicle type of each large cargo.

Therefore, even if the cargo is large and has a low floor height, such as a container vehicle or a moving vehicle,
The ceiling of the loading platform at the rear is higher than the ceiling of the driver's cabin and has large irregularities, which makes it easy to distinguish it from a bus and greatly improves the accuracy of vehicle type identification. .

(Description of Examples) Hereinafter, the present invention will be described in detail based on examples shown in the drawings. FIG. 2 is a configuration diagram of a vehicle type discrimination device according to an embodiment of the present invention, in which 1 is an ultrasonic detection device as a ceiling height detection device for detecting the ceiling height of a vehicle; 2 is an ultrasonic detection device; This is a loop-type detection device that uses a magnetic field to detect the floor height of a vehicle.

The ultrasonic ceiling height detection device 1 includes an ultrasonic transducer 3 and an ultrasonic vehicle sensor 4, and inputs a signal from the ultrasonic vehicle sensor 4 to a control unit 5. Then, the ultrasound transducer 3 transmits pulses intermittently (for example, 30 msec) to reflect the reflected ultrasound on the vehicle ceiling and receive the reflected ultrasound. is configured to detect the height of the ceiling surface.

That is, as shown in FIG. 3a, when the height of the ultrasonic transducer 3 from the road surface is H, and the height of the vehicle ceiling from the road surface is h, as shown in FIG. 3b,
The time difference between the transmission of ultrasonic wave A and the reception of road surface reflected wave B when reflected from the road surface is T (=const),
If the time difference between the time of transmission and the time of reception of the vehicle reflected wave C when reflected from the vehicle ceiling is _t1 , then h=(1/2)・v・T−(1/2)・v・The height h of the vehicle ceiling surface is determined as t ₁ (v: sound speed m/s) = (1/2)·v·(T−t ₁ ).

Also, if we set T-t ₁ = t ₂ and use the proportional relationship, we get h/H=t ₂ /T, which is transformed into h=H・t ₂ /T=H・(T-t ₁ )/ The height h of the vehicle ceiling surface is determined as T. In this case, since the sound velocity v is not used, there is no need to measure the outside air temperature, which has the advantage of simplifying the detection configuration.

The loop-type floor height detection device 2 is composed of a magnetic field generator 6 buried under the road surface and a loop-type vehicle sensor 7, and a signal from the loop-type vehicle sensor 7 is input to the control unit 5. The sensor is configured to detect the floor height of the vehicle by reading the induced voltage change.

The control unit 5 includes an input circuit 8, an output circuit 9,
It is composed of an arithmetic processing unit 10 consisting of ROM, RAM, and CPU.

The arithmetic processing device 10 has vehicle height detection means, speed detection means, vehicle length detection means, vehicle type discrimination means, and vehicle type subdivision discrimination means.

The vehicle height detection means detects the actual vertical height of the vehicle body excluding the wheels, that is, the vehicle height, based on the difference between the height detected by the ceiling height detection device 1 and the height detected by the floor height detection device 2. I'm starting to do that.

The speed detection means includes the floor height detection device 2.
The time difference between when vehicle detection is started by each of the ceiling surface height detection devices 1 and 1 is calculated, the installation interval L between both detection devices 1 and 2 is divided by the above-mentioned time difference, and the result is converted into speed. .

The vehicle length detection means determines the vehicle sensing time from the start of vehicle detection to the end of vehicle detection in either of the detection devices 1 and 2, and calculates the vehicle length by the speed detection means at the vehicle sensing time. The length of the vehicle body in the longitudinal direction, that is, the vehicle length, is calculated by multiplying the speed.

The vehicle type discrimination means distinguishes between passenger cars, small cargo, large cargo, and buses based on vehicle height, vehicle length, and unevenness of the ceiling surface.
The explanation will be based on the flowchart shown in the figure.

That is, it is determined whether the vehicle height is less than 1.5 m (step N1), and if it is less than 1.5 m, it is determined that the vehicle is a passenger car. If the length is 1.5m or more, it is determined whether the vehicle length is less than 4.8m (step N2), and even if the vehicle length is 4.8m or more, it is determined whether the vehicle height is less than 2.0m (step N3). , Vehicle height is 1.5m ~ 2.0m
m vehicles, as well as vehicles with a vehicle height of 2.0 m or more and a vehicle length of
Vehicles shorter than 4.8m are considered small cargo. Vehicle height
For vehicles with a length of 2.0m or more and a vehicle length of 4.8m or more, it is determined whether the floor height is greater than the set value (step N4), and if the floor height is smaller than the set value, the Then, a subdivision is made to determine whether there is a large unevenness change in the ceiling surface (step N5), and if there is a change in unevenness, it is determined that the cargo is a large cargo, and on the other hand, if there is no unevenness change, it is determined that it is a bus.

Based on the above, vehicles are classified into four types: passenger cars, small cargo, large cargo, and buses, and a classification diagram thereof is shown in FIG.

Next, the judgment flowchart as the subdivision discrimination means in step N5 will be explained based on FIG.

First, determine whether sensing is in progress (step
N1), if sensing is in progress, measures the vehicle height (step
N2), and then it is determined whether the number of measurements N is 5 or less (step N3). If it is 5 times or less,
As shown in FIG. 6, the measured values are input to the rise memory 11 for five times and shifted (step N4), and are sequentially updated (step N4).
N5). Next, in step N6, the measured value is input to the falling memory 12 and shifted.Furthermore, when the measured value exceeds 5 times, the measured value for 5 times is finally input to the falling memory 12. input. In step N7, it is determined whether the number of measurements is one, and only if it is one, the measured value is input into each of the maximum value memory 13 and minimum value memory 14 shown in FIG. 6 (step N8). If the number of measurements is not 1, it is step N8.
Is it greater than the maximum value entered in (step N9)?
It is determined whether the measured value is smaller than the minimum value (step N10), and if it is larger than the maximum value, the measured value is input into the maximum value memory 13 (step N11), and
If it is smaller than the minimum value, it is input to the minimum value memory 14 (step N12). At step N1,
If it is determined that sensing is not in progress, the number of measurements is set to 0 (step N13), and then it is determined whether sensing is OFF (step N14). When sensing is OFF, that is,
When the vehicle passes through the detection range of both the detection devices 1 and 2, the speed detection means calculates and measures the vehicle's running speed (step N15), and according to each of the running speeds, the speed is set in advance as described below. The measured value of the number of pulses is removed from the rise memory 11 and the rise memory 12, respectively (step
N16). After removing a predetermined number of measured values, the minimum measured value among the remaining measured values is input into the minimum value memory 14 (step N17). After that, the minimum value is subtracted from the maximum value, and it is determined whether the difference is greater than the set threshold value (step N18), and if it is greater than or equal to the threshold value,
It is determined that there are irregularities (Step N19), and conversely, if it is less than the threshold value, it is determined that there are no irregularities (Step N19).
N20), determine whether it is large cargo or a bus as described above.

An example of setting the number of pulses on the rising side and falling side to be removed according to the traveling speed is as follows.

Traveling speed Rise Fall 5Km/h or less X ₁ ~X ₅ Y ₁ ~Y ₄ 5 ~ 10Km/h X _{2 ~} X _{5 Y 1 ~} Y _{3 10} ~ 20Km/h ~30Km/h X ₄ ~ _{X 5} Y ₁ 30Km/ _h or more
On the bus, on each of its front and rear sides,
Even if the bumper 15 protrudes, the bumper 1
By excluding bumper 15 from the object of unevenness determination, it is possible to discriminate whether it is bumper 15 or large cargo based on the presence or absence of unevenness changes on the ceiling surface, and the accuracy of the discrimination can be further improved.

The means according to steps N15, 16 and 17 above are referred to as removal means.

Note that the present invention may be such that the presence or absence of irregularities is determined without providing the above-mentioned removing means, and thereby it is determined whether the vehicle is a bus or a large cargo.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of vehicle type discrimination means showing an embodiment of the vehicle type discrimination device of the present invention, FIG. 2 is a block diagram showing the configuration of the vehicle type discrimination device, and FIGS. 3 a and b are for vehicle height calculation. FIG. 4 is a classification diagram for vehicle type discrimination, FIG. 5 is a flowchart of the subdivision discrimination means, FIG. 6 is a block diagram of the memory, and FIG. 7 is an operation explanatory diagram. 1... Ceiling surface height detection device, 2... Floor surface height detection device.

Claims (1)

[Claims] 1. Detecting the height of the vehicle ceiling from the time difference between the time of transmitting ultrasonic waves that are pulsed intermittently at set time intervals and the time of receiving ultrasonic waves reflected by the vehicle ceiling surface. a ceiling surface height detection device that detects the height of the vehicle, and a floor surface height detection device that detects the height of the vehicle floor surface provided at a predetermined interval in the direction of vehicle movement; A vehicle height detection means that calculates the vehicle height; A speed detection means that calculates the vehicle running speed based on the time difference between detections by both of the detection devices; and Which of the two detection devices and the speed calculated by the speed detection device. vehicle length detection means for calculating the length of the vehicle in the longitudinal direction based on the vehicle sensing time by one of the vehicle detection means; A discriminating means for discriminating the vehicle type and a detection state of the ceiling surface height detecting device compare the detected heights for each pulse, extract the maximum height and minimum height, and calculate the difference between them. A vehicle type discriminating device includes a subdivision discriminating means for subdividing the vehicle type based on the unevenness of the height relative to the set value by comparing the difference in height with a set value. 2. In the subdivision discrimination means, after the detection by the ceiling surface height detection means starts and before the detection ends, the number of detected values to be removed is reduced as the speed increases according to the speed calculated by the speed detection means. 2. The vehicle type discriminating device according to claim 1, further comprising a removing means for removing a predetermined number of detected values from targets for calculating the difference between the maximum height and the minimum height.