JPS6239510Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vehicle sensing device that senses the presence or passage of a vehicle and outputs the detected information.

Various conventional vehicle sensing devices of this type have been proposed, and some detect outputs not only from moving vehicles but also from pedestrians and the like, depending on their sensing method.

An example of this type of vehicle sensing device is shown in FIG. 1 and will be described. In the figure, reference numeral 1 indicates a path along which a vehicle 2 travels, and arrows indicate the direction in which the vehicle 2 travels. 3 is a vehicle sensor for detecting a vehicle 2 traveling on the passage 1; 4 is a sensing range (sensing area) of the vehicle sensor 3;
Reference numeral 5 denotes a holding time addition circuit that extends and holds the sensing signal for a certain period of time after the vehicle sensor 3 finishes sensing, that is, after the sensing signal ends.

FIG. 2 is an explanatory diagram of the operation of FIG. 1, where a and b show the sensing signal of the vehicle sensor 3, and c shows the sensing signal after passing through the holding time addition circuit 5. . The sensing signal a is a signal that is approximately equal to the passing time of the vehicle as it passes, but as shown in the sensing signal b, so-called pulse splitting may occur in which the signal is divided into two or more. The cause of this pulse cracking differs depending on the type of vehicle detector, but for example, in a photoelectric vehicle detector that detects a vehicle by extending a light beam approximately perpendicular to the course F and blocking this light beam, there is a difference between the light beam and the vehicle. Depending on the positional relationship, the shape of the vehicle, etc., the light beam is not necessarily blocked continuously for a single vehicle, and sensing may be interrupted, resulting in a phenomenon called pulse cracking. Normally, in order to prevent such malfunctions, a holding time adding circuit 5 adds a certain holding time as shown in the sense signal c.

Even if this type of sensing device is used, in order to prevent sensing output from being sent to pedestrians walking on the road, the sensing signal will not be transmitted while a vehicle is within the sensing range (area) of the vehicle sensor. Two vehicle detectors are used, each of which has a sensing range (area) set at a certain distance along the vehicle's path, and when the vehicle passes through this path, the two vehicle detectors operate sequentially to sense the same distance. In other words, if the distance between the sensing ranges (areas) of the two vehicle detectors is larger than the size of the pedestrian you do not want to output, the sensor may output sensing signals to two vehicles at the same time. Two vehicle detectors are arranged so that the length of the vehicle is smaller than the length of the vehicle, and the final vehicle detection signal is generated only when the two vehicle detectors simultaneously output sensing signals for the same vehicle. Vehicle sensing devices that output are conventionally used.

Fig. 3 is a block diagram showing another example of a conventional vehicle sensing device that uses two vehicle detectors to sense and output only the vehicle, and shows the relationship among the vehicle path, the sensor, and the sensing range (area). It shows. In the figure, 1 is the path of the vehicle 2, 3a and 3b are vehicle detectors, and 4a and 4b are vehicle detectors 3a and 3, respectively.
Sensing range (area) b, 5a and 5b are holding time adding circuits that extend and hold the sensing signal for a certain period of time after the vehicle detectors 3a and 3b finish sensing, that is, after the sensing signal ends, and 6 is this holding time. This is a determination circuit that outputs a final vehicle sensing signal from the two sensing signals from the additional circuits 5a and 5b.

FIG. 4 is an explanatory diagram of the operation of FIG. 3, where a shows the sensing signal after the output of the vehicle sensor 3a passes through the retention time addition circuit 5a, and b shows the detection signal of the vehicle sensor 3a.
The output of b shows the sensing signal after passing through the holding time addition circuit 5b, and c shows the final vehicle sensing signal determined from sensing signal a and sensing signal b to be signals simultaneously output by the same vehicle. It is something.

Next, the vehicle sensor 3a shown in FIG.
Fig. 5 shows the detection signal when a pedestrian passes through the place where the sensor 3b is installed. In Figure 5,
a shows the sensing signal output from the retention time addition circuit 5a, and b shows the detection signal output from the retention time addition circuit 5a.
A sensing signal outputted from b is shown, and c is a sensing signal outputted from the determination circuit 6.

In this case, let us consider the conditions under which the determination circuit 6 does not output a sensing signal due to a pedestrian. In FIG. 3, the distance between the sensing ranges (regions) 4a and 4b is L, the size of the pedestrian is H, the holding time is T _H , and the pedestrian's passing speed is υ. Note that the sensing range (area) is assumed to have no size in the direction of movement indicated by the arrow.

Now, considering the generation time difference T ₁ between the two sensing signals, this generation time difference T ₁ is expressed as T ₁ =L/υ, and the length T of the sensing signal output from the upstream retention time addition circuit 5a ₂ , the length T ₂ of this sensing signal is T ₂ =H/υ+T _H. Here, if the length T ₂ of the sensing signal becomes larger than the generation time difference T ₁ , the two sensing signals will overlap in time, and the sensing signal will be output from the determination circuit 6 . Therefore, in order to avoid outputting a sensing signal to pedestrians, it is necessary that T ₁ >T ₂ L/υ>H/υ+T _H (L-H)/υ>T _H.

Next, based on this configuration, if we actually put in concrete numerical values and explain, the retention time is T _H =
200ms, υ = 4m/s as the pedestrian's running speed
(14.4Km/H), H = 30cm as the size of a pedestrian
Then, from these values, two sensing ranges (areas) are determined.
Calculating the interval L, L = 110cm, and in the above example, there are two sensing ranges (areas).
Unless the distance between 4a and 4b is made larger than 110 cm, the final sensing signal will be output by the pedestrian. Further, in the above example, if we consider a case where the value of the holding time T _H and the pedestrian passing speed υ are even larger, it is necessary to further increase the interval L between the two sensing ranges (regions).

In this way, when using two vehicle detectors and trying to output a sensing signal only to the vehicle, conventional methods have been used in which the retention time has no effect, that is, the retention time is small and two sensing ranges are used. This was limited to cases where the distance between (regions) was relatively large.

However, if the two sensing ranges (areas) are made smaller and the retention time is increased, when a pedestrian runs through, even though the pedestrian is not actually within the two sensing ranges (areas) at the same time. First, there is a problem in that the sensing signal is extended due to the holding time, resulting in two sensing signals overlapping each other, and the sensing signal is finally output.

In view of the above points, the present invention provides a vehicle sensing device designed to solve such problems.The present invention provides a vehicle sensing device that is designed to solve these problems. A holding time addition circuit is provided to extend and hold the sensing signal for a certain period of time after completion, and the holding time prevents false sensing such as pulse breakage.Furthermore, the output is prohibited for a certain period of time from the point at which the sensing signal is generated. An output delay circuit is provided to delay the generation of the signal, and when the sensing signals of two vehicle sensors are simultaneously output to the same vehicle after passing through two circuits: a holding time addition circuit and an output delay circuit, The final vehicle sensing signal is output only when the vehicle is sensed, thereby eliminating the disadvantages of the conventional case where only a holding time is added.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. As mentioned above, there are various sensing methods, but here we will explain the photoelectric vehicle sensor as an example, which is thought to have a particularly large effect according to the present invention. In this photoelectric vehicle sensor, the size of the sensing range (sensing area) in the direction of travel can be practically ignored.

FIG. 6 is a block diagram showing an embodiment of the vehicle sensing device according to the present invention. In the figure, 1 is a path along which a vehicle 2 travels, 3a and 3b are vehicle sensors, and 4
a and 4b are the sensing ranges (sensing areas) of the vehicle detectors 3a and 3b, respectively, and 5a and 5b are the inputs of the outputs of the vehicle detectors 3a and 3b, respectively, after the vehicle sensor finishes sensing, that is, after the sensing signal ends. , a holding time adding circuit 5 for extending and holding the sensing signal for a required fixed time; 7a and 7b are holding time adding circuits 5, respectively;
An output delay circuit which receives the outputs of outputs a and 5b and prohibits output for a certain period of time from the time of generation of the sensing signal, that is, delays the generation of the sensing signal, and 6 receives the outputs of the output delay circuits 7a and 7b and outputs the two sensing signals. This is a determination circuit that outputs a final vehicle sensing signal from the And retention time adding circuits 5a and 5, respectively.
It is configured to output the final vehicle detection signal only when the detection signals of the two vehicle detectors 3a and 3b which have passed through the output delay circuits 7a and 7b are simultaneously output to the same vehicle. attitude.

Next, the operation of the embodiment shown in FIG. 6 will be explained with reference to FIG. First, the output delay circuit 7a,
7b is a circuit that delays the generation of the sensing signal by prohibiting output for a certain period of time from the point of time when the sensing signal is generated; for example, if the output is delayed by the same amount of time as the holding time added by the holding time addition circuits 5a and 5b, the output is delayed depending on the holding time. The effect of preventing pulse breakage remains the same, and the generation time difference between the two sensing signals and the length of the sensing signal are the same as when no holding time is added at all, and the holding time has no effect on the judgment circuit 6. Become. However, the output delay time does not need to be the same as the retention time, and the relationship between the magnitude for determining output/non-output and the interval between the two sensing ranges (regions),
An appropriate time can be set depending on the conditions of the site, such as the speed of passing vehicles and the traffic conditions of pedestrians.

FIG. 7 shows the relationship between the signals detected by pedestrians in FIG. 6, where a and b indicate the outputs of the vehicle detectors 3a and 3b, respectively, and c,
d indicates the outputs of the retention time adding circuits 5a and 5b, respectively, and e and f indicate the output delay circuits 7a and 7, respectively.
This shows the output of b. In c, T _H indicates the holding time, and in e, T ₃ indicates the output delay time.

Now, the holding time T _H of the holding time adding circuit 5b,
When the output delay time _T3 of the output delay circuit 7b is set to be equal, the output signal shown in FIG. 7c output from the holding time addition circuit 5b is output from the output delay circuit 7b after the delay time _T3 . Therefore, the rising point of the output signal of the output delay circuit 7b is a delay time T ₃ after the rising point of the signal shown in FIG. 7c, which is the output signal of the holding time adding circuit 5b, as shown in FIG. 7e. be. The output signal duration time of the output delay circuit 7b is a period _T3 shorter than the output signal of the holding time 5b shown in FIG. 7c, that is, the same period as the signal duration time shown in FIG. 7a. Note that the signal in Figure 7a and the signal shown in Figure 7e have almost the same shape, but even if the signal in Figure 7a has a pulse break, the signal in Figure 7e has an output delay. Since the signal is passed through the circuit 7b, no pulse breakage occurs. Further, the signal of the output delay circuit 7a shown in FIG. 7f is also outputted in the same manner.

Therefore, even if a pedestrian crosses the sensing ranges 4a and 4b, the signals output from the output delay circuits 7a and 7b do not overlap as shown in FIG. 7e and f, so that false detection is prevented. do not have. On the other hand, in the case of a vehicle, since the distance between the vehicle sensors 3a and 3b is set to be shorter than the length of the vehicle, the signals shown in FIG. 7e and f are generated simultaneously.

Since the present invention is configured in this way, the holding time T _H shown in FIG. ) can be made close to the size of a pedestrian, that is, a human, and the device can be made more compact. Furthermore, since the distance between the two sensing ranges (regions) can be made smaller, it becomes possible to distinguish between motorcycles and humans, which has not been possible in the past.

As explained above, according to the present invention, it is not only possible to proactively increase the retention time within a range that does not affect the vehicle resolution, but also to bring the distance between the two sensing ranges close to the size of a human. It is also possible to reduce the size of the device and improve its aesthetic appearance. Furthermore, since the distance between the two sensing ranges can be reduced, it is possible to distinguish between a motorcycle and a human, which has not been possible in the past, and has a very large and effective feature not found in the past.

Therefore, according to the present invention, it is possible to realize a highly accurate vehicle sensing device suitable for measuring the number of vehicles passing at toll gates of toll roads, etc., and the practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional vehicle sensing device, FIG. 2 is an explanatory diagram of the operation of FIG. 1, and FIG. 3 is a block diagram showing another example of the conventional vehicle sensing device.
Figures 4 and 5 are operation explanatory diagrams of Figure 3;
The figure is a block diagram showing one embodiment of the vehicle sensing device according to the present invention, and FIG. 7 is an explanatory diagram of the operation of FIG. 6. 3a, 3b...Vehicle sensor, 5a, 5b...Holding time addition circuit, 6...Judgment circuit, 7a, 7b...
...Output delay circuit.

Claims (1)

[Scope of utility model registration request] Two vehicle detectors 3a, 3b, which continue to output sensing signals while a vehicle is present in the sensing area of the vehicle detector, are used, and each of the vehicle detectors 3a, 3b continues to output a sensing signal.
The sensing areas 4a, 4b of 3b are installed on the path of the vehicle so that they are larger than the size of the pedestrian and smaller than the length of the vehicle 2, and when the vehicle 2 passes through the path, the two vehicle detectors 3a, 3b
The two vehicle detectors 3 are arranged so that the two vehicle detectors 3 perform sensing operations sequentially and simultaneously output sensing signals to the same vehicle 2.
a, 3b are arranged, and the two vehicle sensors 3a, 3
In the vehicle sensing device which outputs the final vehicle sensing signal only when the sensor b outputs sensing signals to the same vehicle 2 at the same time, each sensor is connected to the output of the first and second vehicle sensor 3a, 3b, First and second holding time adding circuits 5a and 5b each holding the sensing signal for an extended period of time after the sensing signal ends.
and the first and second holding time adding circuits 5
first and second output delay circuits 7a and 7b connected to the outputs of the sensors a and 5b, respectively, for inhibiting output for a required time from the generation of the sensing signal and delaying the generation of the sensing signal; The sensing signals of the first and second two vehicle sensors 3a, 3b which have passed through the holding time addition circuits 5a, 5b and the first and second output delay circuits 7a, 7b, respectively, are output to the same vehicle simultaneously. A vehicle sensing device characterized in that it is provided with a determination circuit 6 that outputs a final vehicle sensing signal only when the vehicle is being detected.