JPS6244319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle type identification device for buses and trucks, which is required at toll collection points on motorways, traffic volume survey locations, and the like.

The toll classifications on toll roads are divided into "regular vehicles,""largevehicles," and "extra large vehicles," so it is necessary to distinguish between these vehicle types. To distinguish between "regular cars" and "large cars," the number of axles, number of wheels,
Many devices have already been proposed that focus on differences in tread, which is the distance between the centers of left and right tires, and measure these to determine the difference (for example, see Japanese Patent Laid-Open No. 19051/1983). However, it is difficult to distinguish between "large vehicles" and "extra-large vehicles" because the classification principle described above may not hold, and in particular buses other than route buses are classified as "extra-large vehicles." This makes it difficult to distinguish between "large vehicles" and "extra-large vehicles." However, focusing on the fact that buses are the only vehicles that can be classified as "extra-large vehicles" even though they have two axles, we first use conventional technology to identify two-axle vehicles, and then conduct further tests such as tread measurement. With the conventional technology, if a "regular car" is identified and removed from among the two-axle vehicles, then if a bus is identified from the remaining vehicles, it becomes an extra-large vehicle. In other words, the problem to be solved is how to distinguish between buses and trucks. The present invention relates to a bus/truck discrimination device which is required due to the above-mentioned circumstances.

FIG. 1 is a conceptual diagram showing an example of a conventional bus discrimination device, in which a is a top view and b is a side view. In the figure, 1 is a bus, 2 is an ultrasonic sensor consisting of an ultrasonic transmitting element and a receiving element, and 3 is an installation pole to which the ultrasonic sensor 2 is attached.

The bus determination device shown in the figure measures the height and length of a traveling vehicle by installing one or two ultrasonic sensors 2 on an installation pole 3 at a height comparable to the roof of the bus 1. However, there are the following problems.

(b) A truck with the same height and length as a bus (for example, a vehicle loaded with freezer containers) will be incorrectly determined to be a bus.

(b) When two ultrasonic sensors are used, two installation poles are required, which increases the installation cost.

(c) When using one ultrasonic sensor, accurate determination becomes difficult due to the influence of vehicle speed.

Another conventional example is a bus discrimination device using a silhouette method shown in FIG.

In FIG. 2, 4 is a reflective photoelectric switch; 5 is a reflective photoelectric switch;
6 is a reflector, 6 is a vehicle speed detector, and 7 is a determination control device. The bus determination device shown in FIG. 2 uses a photoelectric switch group consisting of a large number of photoelectric switches and a vehicle speed detector 6 to create a silhouette of a vehicle passing between the photoelectric switch group and the reflector 5, and then creates a silhouette of a vehicle passing between the photoelectric switch group and the reflector 5. This method discriminates by comparing the values, but this method has the following problems.

(b) It requires a vehicle speed detector, making it an expensive system.

(b) It requires a large amount of memory, such as a memory for the running vehicle's silhouette and a memory for the standard vehicle silhouette, making the judgment control device expensive.

This invention has been made to solve the problems in the prior art as described above, and an object of the invention is to provide a single type discrimination device for buses and trucks that has high judgment accuracy and is inexpensive. There is a particular thing.

The gist of the configuration of this invention is to target a passing vehicle (traveling vehicle) whose number of axles is two and whose tread is determined to be that of a large vehicle. A sound wave transmitting element and an ultrasonic wave receiving element are provided, the transmitting element is driven at a constant repeating cycle to transmit ultrasonic waves, and the number of reflected ultrasonic pulses received by the receiving element is counted for each cycle, The difference is that the type of vehicle (bus or truck) is determined using the count results.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a perspective view showing a vehicle type discrimination device to which the present invention is implemented. In the figure, 11 is a running vehicle, 12 is a running road surface, 13 is a light emitting tower, 14 is a light receiving tower, 15 is a light emitter attached to the light emitting tower 13, 1
6 is a light receiver attached to the light receiving tower 14, and 17 is a conventionally known wheel information detection device buried in the road surface, which is made of pressure-sensitive conductive rubber, a resistor, etc. , the tread, etc., which is the distance between the centers of both the left and right tires (for an example, please refer to Japanese Patent Application Laid-open No. 1988-19051 if necessary). 18 is an ultrasonic sensor (consisting of a transmitting element and a receiving element), 19 is a light receiving tower 14
Nearby is a control device, and 21 is a booth (toll gate). Light emitter 15 and light receiving tower 14 provided in light emitter 13
It corresponds to the light receiver 16 provided at the top, and a light screen is formed between the two. An ultrasonic sensor 18 is provided at a suitable height position of the light emitting tower 14 (or the light emitting tower 15), and since this is related to the present invention, it will be explained in detail later.

Next, the operation will be explained. The traveling vehicle 11 is the luminous tower 1
Each unit is separated by blocking the optical screen formed by the light emitter 15 provided at the light receiving tower 14 and the light receiver 16 provided at the light receiving tower 14. Furthermore, the wheel information detection device 17 detects the number of axles and wheels of the traveling vehicle 11,
The tread and the like are measured, and using this information, the control device 19 distinguishes between a regular car, a large car, and an extra large car to a considerable degree by following the procedure shown in FIG.

Please refer to FIG. As mentioned above, since the wheel information detection device 17 has detected the number of axles, number of wheels, tread, etc. of the traveling vehicle 11, first, step 1 is performed.
In step 3, it is checked whether the number of axles of the vehicle is two, and if no, then in step 3 it is checked whether the number of axles is three. If YES, in step 3, it is checked whether the vehicle is a large car or not, and if YES, it is determined that it is a large car, and if NO, it is determined that it is a regular car. If it is determined in step 2 that the number of axes is not three, the process proceeds to step 4, where it is checked whether the number of axes is four. If yes, in step 5, it is checked whether the vehicle is extra large or not based on the number of wheels, etc. If yes, it is judged as an extra large car, and if no, it is judged as a large car. If step 4 is NO, it means that it has 5 or more axles, so it is definitely determined to be an oversized vehicle.

On the other hand, if the answer is yes in step 1, it is checked in step 6 whether the vehicle is a large car or not. Buses are also included in large vehicles, and if they are buses, they must be reclassified as extra-large vehicles (the circumstances in between are due to the fee structure, as explained earlier). Therefore, the flowchart of the subsequent operations when the determination in step 6 is YES is shown again in FIG. 4A.

In FIG. 4A, there is a step 7 that asks whether the vehicle is a bus, and if YES, it is an extra-large vehicle, and if NO, it is a truck, so it is determined that the vehicle is a large vehicle. This step 7
As the discrimination means, the ultrasonic vehicle type discrimination device of the present invention is used.

From the above explanation, it seems that the position occupied by the discriminating device according to the present invention in the overall vehicle type discriminating system has been understood, and therefore embodiments of the present invention will be specifically described below.

FIG. 5 is a block diagram showing one embodiment of the present invention. In the same figure, 22 is a reference pulse generation circuit, 23 is an ultrasonic drive circuit (driving means for driving the transmitting element at a constant repetition period), 24 is a waveform shaping/mask circuit, and 25 is a counting circuit (the signal received by the receiving element is 26 is a determination circuit (determination means for determining whether the type of vehicle is a bus or a truck);
27 is a transmitting element, 28 is a receiving element, and 29 is a conventionally known axis number counting circuit. The ultrasonic transmitting element 27 and the receiving element 28 constitute the ultrasonic sensor 18 in FIG. 3, and are installed at approximately the same height as the center of the tire axis of a large vehicle such as a bus or truck. It is.

FIG. 6 is a time chart showing the transmission and reception pulse waveforms of ultrasonic waves in the circuit of FIG.

The operation will be explained with reference to FIGS. 5 and 6. The timing (period) T _p of transmitting an ultrasonic pulse from the ultrasonic transmitting element 27 is the reference pulse generating circuit 22
The value is set in the ultrasonic sensor 2.
It is determined from the distance from 7, 28 to the side of the traveling vehicle 11 and the speed of sound, and for example, about 20 ms is appropriate at a toll gate or booth where the width of the traveling road is determined to be a certain length. The time period during which the ultrasonic waves are emitted is preferably as short as possible within the range in which the transmitting element 27 responds to the drive circuit 23, for example about 0.5 ms. The transmitted waveform is shown in Figure 6a. That is, an ultrasonic pulse of duration T _s is sent out every period T _p . When the vehicle 11 is not near the ultrasonic sensors 27 and 28, the received wave R _I is as shown in FIG. 6b.
There is no received wave other than the waveform in which the pulse emitted from the transmitting element 27 goes around to the receiving element 28 as it is. Therefore, the received wave R _I is rectified and smoothed by the waveform shaping/masking circuit 24, and the reflected wave at the time of transmission is masked, resulting in a signal R _p , which does not contain any received signal, as shown in FIG. 6b.

When a bus passes near the ultrasonic sensors 27 and 28, the ultrasonic pulse is reflected only from the side plate P of the bus as shown in Fig. 7, so the received wave is as shown in Fig. 6c. It becomes a waveform. That is, one received wave is obtained within the transmission period T _p , for example, T _R ms after transmission, so one pulse is output as the output R _p of the waveform shaping/masking circuit 24. Let me explain in a little more detail. FIG. 7a is a rear view of the bus 34, in which ultrasonic pulses are directed toward the side plate P of the pulse 34 from the ultrasonic sensors 27 and 28 installed at a height approximately equal to the axial center of the tires of the bus 34. Indicates the status of the transmission. Further, FIG. 7b is a side view of the bus 34, and the pulses emitted from the ultrasonic sensor placed at the height indicated by the line (-) (height near the center of the tire axis) are approximately located at the side plate P. It will be understood that it is reflected from

On the other hand, in FIG.
When the truck passes near the side plate Q of the truck 31, as shown in FIG. Since the ultrasonic pulse is also reflected from the tank ₎ , the received wave is ₂ .
There is always a case where the pulse waveform consists of three or more pulse waveforms. To explain in more detail, Figures 8a and 8b are a rear view and a side view of the truck, respectively, and are similar to Figures 7a and 7b. In the case of a bus, as is clear from Fig. 7, the side plate is a single flat plate, but in the case of a truck, as is clear from Fig. 8, in addition to the side plate Q, the side plate is a flat plate. It has a complex structure. For this reason,
The ultrasonic sensor placed at the position indicated by the line Y-Y (equivalent to the position indicated by the line - in Fig. 7) receives not only the reflected wave from the side plate Q but also the reflected wave from the appendage R. It is.

Next, returning to FIG. 5, in the counting circuit 25, each cycle is counted from the time when the front axle of the vehicle passes until the time when the rear axle passes (this period is detected by the axle number counting circuit 29). Count the pulses received within each T _p period. That is, if not a single pulse is obtained as the output R _p in a certain period T _p (FIG. 6b), the 0 pulse counter in the counting circuit 25 counts this fact. Similarly, when two pulses are obtained as the output R _p in one period T _p (FIG. 6d), the 2-pulse counter counts 1. Similarly, the 3 or more pulse counter counts when 3 or more pulses are obtained as the output R _p in one period T _p .

As mentioned above, only one pulse is reflected from the side plate of the bus, but the side of the truck is structurally very complex, and there are side plates, attachments, and gaps that penetrate through. There is also room for a 0-pulse counter that operates when there is no reflected pulse. Ultrasonic pulse transmission period T _p
Needless to say, is selected to be sufficiently small compared to the vehicle transit time.

The determination circuit 26 determines that it is a truck when the output of the counting circuit 25 exceeds a certain preset threshold, and otherwise determines that it is a bus. 9th
The figure is a flowchart showing the determination operation by the determination circuit 26. In step (B) in the figure, 2 is selected as the threshold value, and when it is equal to or greater than 2, it is determined to be a truck, and when it is less than that, it is determined to be a bus. The counting circuit 25 in FIG. 5 integrates the count values of a 0 pulse counter, a 2 pulse counter, and a 3 or more pulse counter, and the judgment circuit 26 makes a judgment based on the integrated values. Step (B) in FIG. 9 is particularly shown.

According to the vehicle type discriminating device for buses and trucks of the present invention, the following effects can be obtained.

(b) Since there is no need to measure the length of the vehicle, there is no need to specifically measure the "vehicle speed"-> an inexpensive configuration.

(b) The reflected waves from the wide side surfaces of the vehicle are measured, and each group of reflected waves is measured. → A sensor with wide directivity can be used, and as a result, the sensor can be made smaller, and the ultrasonic pulse Since there is no need to strictly measure the time between transmission and reception, there is no need to consider the vehicle traveling position or the influence of wind.

(c) Measurement of reflected waves by group is performed only from the time the front axle passes until the rear axle passes → Even if the vehicle is in a busy road, it can be distinguished without being affected by the vehicle in front or the rear. It is possible.

(d) The distance from the sensor to the vehicle can be set short → measurement accuracy can be ensured.

(E) Measured below the loading platform → not affected by the load.

(F) In the case of bus measurement, ultrasonic noise may be generated from the second axis onwards, and two received waves may be obtained from the tire part, but the judgment is only made between the 1st and 2nd axes. It is not affected by that.

(G) In the case of track measurement, ultrasonic noise is often generated between the first and second axes, but this discrimination method is not affected by this noise.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an example of a conventional bus identification device, FIG. 2 is a perspective view showing another example of the conventional bus identification device, and FIG. 3 is a diagram showing a vehicle type identification device to which the present invention is applied. FIG. 4 is a flowchart showing a vehicle type discrimination operation in a vehicle type discrimination device to which the present invention is implemented, FIG. 4A is a detailed view of a part of the flowchart in FIG. 4, and FIG. A block diagram showing one embodiment, FIG. 6 is a time chart showing the ultrasonic transmission/reception pulse waveform in the circuit of FIG. 5, and FIG. 7a is a rear view of the bus.
7b is a side view of the same, FIG. 8a is a rear view of the truck, FIG. 8b is a side view of the same, and FIG. 9 is a flow chart showing the determination operation of the determination circuit in FIG. Code explanation, 1...Bus, 2...Ultrasonic sensor,
3... Installation pole, 4... Reflective photoelectric switch, 5... Reflector, 6... Vehicle speed detector, 7...
... Judgment control device, 11 ... Traveling vehicle, 12 ... Road surface, 13 ... Light emitting tower, 14 ... Light receiving tower, 15 ...
Light emitter, 16... Light receiver, 17... Wheel information detection device, 18... Ultrasonic sensor, 19... Control device, 21... Booth, 22... Reference pulse generation circuit, 23... Ultrasonic drive circuit , 24... Waveform shaping/mask circuit, 25... Counting circuit, 26... Judgment circuit, 27... Transmitting element, 28... Receiving element,
29... Axis number counting circuit.

Claims (1)

[Scope of Claims] 1. A bus and truck system that determines whether the vehicle is a bus or a truck, with the number of axles being two and the torpedo determined to be that of a large vehicle. In this vehicle type discrimination device, an ultrasonic transmitting element 27 and a receiving element 28 are installed at a height near the center of a tire of a bus as a vehicle, and the transmitting element 27 is driven at a constant repetition period to detect the passing vehicle. a driving means 23 for transmitting ultrasonic pulses; and a 0 pulse counter for counting the number of reflected pulses received by the receiving element 28 in each cycle and generating an output when the number is 0. A 2-pulse counter generates an output when the value is 3 or more, and a 3-pulse counter 25 generates an output when the value is 3 or more.By comparing the output value from each counter with a set value, it is determined whether the type of the passing vehicle is a bus or not. A vehicle type discrimination device for buses and trucks, characterized in that it comprises means 26 for determining whether the vehicle type is a bus or a truck.