JPH0648097U - Vehicle type identification device - Google Patents

Abstract

(57) [Abstract] [Purpose] Ultrasonic type vehicle detectors 11 and 12 are arranged at two locations, upstream and downstream, along the traveling direction of a road, and these two vehicle detectors 11 and 12 simultaneously. Sensing signals K11, K1
In the vehicle type identification device that determines the length of the vehicle based on whether or not 2 is output and determines the vehicle type from the determination result, the accuracy is improved regardless of the speed of the vehicle. [Structure] Detection signal K11 of the vehicle detector 11 on the upstream side
A delay timer 14 for delaying the detection signal K12 of the vehicle detector 12 on the downstream side is provided for a time substantially equal to the holding time.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 According to the present invention, ultrasonic type vehicle detectors are arranged at two locations, upstream and downstream, along the traveling direction of a road. Depending on whether or not these two vehicle detectors simultaneously output detection signals, The present invention relates to a vehicle type determination device that determines whether a vehicle is long or short and determines the vehicle type based on the determination result.

[0002]

[Prior art]

 Conventionally, as a device for automatically discriminating whether a vehicle passing a road is a large vehicle or a small vehicle, ultrasonic type vehicle detectors are arranged at two locations, upstream and downstream, along the traveling direction of the road. 2. Description of the Related Art There is known a vehicle type identification device that determines the length of a vehicle based on whether or not vehicle detectors at different locations simultaneously output a detection signal, and determines the vehicle type from the result of this determination.

That is, as shown in FIGS. 4 and 7, this device is provided with vehicle detectors 1 and 2 which are arranged at a distance corresponding to a vehicle length which is a boundary between a large vehicle and a small vehicle, and vehicle detectors 1 and 1. When there is a time (hereinafter referred to as a lap time) at which the sensing signals K1 and K2 are simultaneously output from both parties, a signal indicating a large vehicle is output, and a signal indicating a small vehicle is output when there is no lap time. The determination unit 3 outputs a signal. The vehicle detectors 1 and 2 each have an ultrasonic wave transmitting / receiving unit and are placed 5 to 6 m above the road surface. The vehicle detectors 1 and 2 project ultrasonic waves of a predetermined frequency toward the road surface, and the sound waves are reflected by an object. Whether or not there is a vehicle is determined by the time it takes to reach the transmitting / receiving unit.

The cycle TS for transmitting the ultrasonic waves is an intermittent transmission which is usually repeated in about 30 to 85 ms, and the ultrasonic waves may not be temporarily returned to the transmitting / receiving unit due to the shape of the reflecting object. In order to remedy these, the set value TH has a holding time timer of 100 to 600 ms, and as shown in FIG. 5, each vehicle detector 1, 2 holds the holding time after receiving the final sound wave with the vehicle. The detection signals K1 and K2 are continuously output only for TH.

[0005]

[Problems to be solved by the device]

 Therefore, a small vehicle having a vehicle length slightly shorter than the distance between the vehicle detectors 1 and 2 may be determined to be a large vehicle when passing at high speed. This is because, immediately after the rear end of such a small vehicle has passed the detection position of the vehicle detector 1 on the upstream side, the tip of this small car has not yet reached the detection position of the vehicle detector 2 on the downstream side. However, after that, when the tip of the small vehicle reaches the detection position of the vehicle detector 2 on the downstream side within the holding time TH, the detection signal K1 of the vehicle detector 1 on the upstream side is output. As shown in FIG. 6, there is a lap time in which the detection signals K1 and K2 are simultaneously output from both vehicle detectors 1 and 2.

The present invention has been made by paying attention to the problems of the conventional technique, and an object of the present invention is to provide a vehicle type identification device capable of accurately identifying the vehicle type regardless of the speed of the vehicle.

[0007]

[Means for Solving the Problems]

 The gist of the present invention for achieving such an object is that ultrasonic type vehicle detectors (11, 12) are arranged at two locations, upstream and downstream, along the traveling direction of the road. In the vehicle type discriminating device for discriminating the vehicle type based on whether or not the vehicle detectors (11, 12) simultaneously output the detection signals (K 11, K 12) and discriminate the vehicle type based on the determination result, the upstream side A delay timer for delaying the detection signal output (K12) of the vehicle detector (12) on the downstream side by a time substantially equal to the holding time (TH) of the detection signal output of the vehicle detector (11). 14) is provided in the vehicle type identification device.

[0008]

[Action]

 With the above-mentioned configuration, the delay timer (14) functions to allow the downstream vehicle detector (12) to have a time substantially equal to the holding time (TH) of the detection signal output (K11) of the upstream vehicle detector (11). Since the detection signal output (K12) in 1) is delayed, the time lag of the vehicle detection due to the holding time (TH) is canceled, and the vehicle length is accurately determined regardless of the vehicle speed.

For example, when a small vehicle having a vehicle length slightly shorter than the arrangement interval of the vehicle detectors (11, 12) passes at a high speed, the rear end of the small vehicle detects the vehicle detector (11) on the upstream side. After passing through the exit position, even if the tip of the small vehicle reaches the detection position of the vehicle sensor (12) on the downstream side within the holding time (TH), the tip of the vehicle sensor (12) on the downstream side is reached. ), The detection signal (K12) from the vehicle detector (12) on the downstream side is not output for the delay time (TD) substantially equal to the holding time (TH). When the sensing signal (K12) of the device (12) is output, the sensing signal output (K11) of the upstream vehicle detector (11) is always completed, and it is surely determined that the vehicle is a small vehicle.

Further, when a large vehicle having a vehicle length slightly longer than the arrangement interval of the vehicle detectors (11, 12) passes at a high speed, the tip of the large vehicle is the vehicle detector (12) on the downstream side. The detection signal (K12) from the vehicle detector (12) on the downstream side is not output for the delay time (TD) from the time when the vehicle reaches the detection position, but the rear end of this large vehicle is on the upstream side during this time. Even if the vehicle has passed the detection position of the sensor (11), the holding time (TH) substantially equal to the delay time (TD) from the time of the passage of the vehicle detector (11) on the upstream side. Since the detection signal output (K11) is held, the detection signal (K11, K12) of both vehicle detectors (11, 12) is always output at the same time. .

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 2, the vehicle type discriminating apparatus according to the present embodiment includes vehicle detectors 11 and 12, a discriminating unit 13 including a delay circuit 14 (delay timer), an input interface 15 and an output interface 16. Become.

The vehicle detectors 11 and 12 have the same structure as conventional ones. That is, it has an ultrasonic transmitter / receiver unit and is arranged 5 to 6 m above the road surface, projects an ultrasonic wave of a predetermined frequency toward the road surface, and the sound wave is reflected by an object and reaches the transmitter / receiver unit. The presence or absence of a vehicle is determined according to the time taken. These vehicle detectors 11 and 12 are arranged upstream and downstream along the road at a distance of a vehicle length, which is a boundary between a large vehicle and a small vehicle. The detection signals of the vehicle detectors 11 and 12 are held for the holding time TH 1.

The discriminating unit 13 is configured as a digital circuit, and includes a delay circuit 14 and a discriminating circuit 15. The delay circuit 14 is, for example, a so-called delay circuit in which a gate circuit is combined, and the output thereof rises after a delay time TD when there is an input. The detection signal K12 of the vehicle detector 12 on the downstream side is input to the delay circuit 14 via the input interface 15, and the output of the delay circuit 14 is input to the determination circuit 15. Here, the delay time TD is set to be substantially equal to the holding time TH.

The discrimination circuit 15 receives the sensing signal K11 input via the input interface 15 and the sensing signal K12 input via the input interface 15 and the delay circuit 14, and these two are input. When there is a time (hereinafter referred to as lap time) that is input at the same time, a large signal HB indicating a large vehicle is output, and when there is no lap time, a small signal HS indicating a small vehicle is output. .

The input interface 15 converts the form of the sensing signals K11 and K12 into the form of the signal (digital signal) in the discriminating unit 13. The output interface 16 converts the small signal HS and the large signal HB output from the discriminating circuit 15 into a form that finally handles them. The input interface 15 and the output interface 16 are not essential constituent elements and are omitted in FIG.

Next, the operation will be described. With the above configuration, the delay circuit 14 acts to delay the detection signal K12 of the vehicle detector 12 on the downstream side by a time substantially equal to the holding time TH of the detection signal K11 of the vehicle sensor 11 on the upstream side. The time lag in vehicle detection due to time TH is canceled out, and accurate vehicle length determination is performed regardless of the speed of the vehicle.

For example, when a small vehicle having a vehicle length slightly shorter than the arrangement interval of the vehicle detectors 11 and 12 passes at a high speed, the rear end of the small vehicle passes the detection position of the upstream vehicle detector 11. After that, even if the tip of the small vehicle reaches the detection position of the vehicle detector 12 on the downstream side within the holding time TH, the holding is started from the time when the tip reaches the detection position of the vehicle detector 12 on the downstream side. Since the detection signal K12 of the vehicle detector 12 on the downstream side is not output for the delay time TD substantially equal to the time TH, when the detection signal K12 of the vehicle detector 12 on the downstream side is output, the vehicle detection on the upstream side is surely performed. Since the output of the sensing signal K12 from the container 11 has ended, it is surely determined that the vehicle is a small vehicle.

Further, when a large vehicle having a vehicle length slightly longer than the arrangement interval of the vehicle detectors 11 and 12 passes at a high speed, the tip of the large vehicle is located at the detection position of the vehicle detector 12 on the downstream side. From the time when it reaches the delay time TD, the detection signal K12 of the vehicle detector 12 on the downstream side is not output, but the rear end of this large vehicle passes the detection position of the vehicle detector 11 on the upstream side during this time. Even if this is the case, since the detection signal K12 of the vehicle detector 12 on the upstream side is held for a holding time substantially equal to the delay time TD from the time of this passage, the detection signals of both vehicle detectors 11 and 12 must be held. There is a lap time when K11 and K12 are output at the same time, so it is definitely judged as a large vehicle.

Note that, according to the reflected wave return time detected by the vehicle detectors 11 and 12, the vehicle height can be detected and the vehicle type can be determined as in the conventional case.

[0020]

[Effect of device]

 According to the vehicle discrimination device of the present invention, the delay timer functions to delay the detection signal output of the downstream vehicle detector by a time substantially equal to the holding time of the detection signal output of the upstream vehicle detector. The time lag in vehicle detection due to the holding time is canceled out, and the vehicle length is accurately determined regardless of the vehicle speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a discriminating unit in a vehicle discriminating apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of a vehicle discriminating apparatus according to an embodiment of the present invention.

FIG. 3 is a timing chart showing the operation of the vehicle discrimination device according to the embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional vehicle discrimination device.

FIG. 5 is a timing chart showing characteristics of a vehicle detector in a conventional vehicle discrimination device.

FIG. 6 is a timing chart showing the operation of a conventional vehicle discrimination device.

FIG. 7 is a diagram showing an arrangement state of vehicle detectors.

[Explanation of symbols]

 11, 12 ... Vehicle detector 14 ... Delay timer (delay circuit)

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[Procedure amendment]

[Submission date] February 16, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

Claims (1)

[Scope of utility model registration request] 1. An ultrasonic type vehicle detector is arranged at two locations, an upstream side and a downstream side, along a traveling direction of a road, and a vehicle is detected depending on whether these two vehicle detectors simultaneously output a detection signal. In the vehicle type discriminating apparatus that discriminates the length of the vehicle type from the result of the determination, the detection signal of the vehicle sensor on the downstream side is equal to the holding time of the detection signal output of the vehicle sensor on the upstream side. A vehicle type identification device having a delay timer for delaying output.