JPS6339959B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses wheel passing detectors to determine the number of vehicles, speed,
It relates to a vehicle type identification device that identifies vehicle types, and can easily and accurately identify the number of vehicles, especially those with different numbers of axles.
This relates to a vehicle sensor that can determine the speed and type of vehicle. Conventional devices of this type include two tape switches or rubber hoses, as shown in Figure 1.
Wheel passing detectors (hereinafter referred to as wheel detectors) A and B consisting of switches are installed in parallel on the road, crossing the direction of travel of the vehicle C, and the axle spacing (axle distance) is determined by the following means. Cl was being measured. In addition, in the figure, l indicates the installation interval of wheel detectors A and B, and an arrow indicates the traveling direction of vehicle C. Assuming that vehicle C passes wheel detector A and wheel detector B at vehicle speed V, the time from when the front wheels of both C pass wheel detector A until the rear wheel passes is _T1 . , and the front wheel is wheel detector A.
The time it takes to pass through wheel detector B
If T ₂ , each of these times T ₁ and T ₂ is expressed as T ₁ =Cl/V (1) T ₂ =l/V (2). From equations (1) and (2) above, Cl=l・T ₁ /T ₂ ...(3) Therefore, by measuring T ₁ and T ₂ using equation (3), the axle distance Cl can be determined and the type of vehicle can be determined. Can be classified. The above explanation was based on the case where l>Cl, but even when l<Cl, the axle distance Cl can be similarly calculated and the vehicle type can be classified using the above equation (3) of Cl=l・T ₁ /T ₂ . . The calculated information on the axle distance Cl obtained in this way is applied to a vehicle type classification circuit to classify the vehicle according to the length of the axle, and the output thereof is configured to operate a counter to count the number of vehicles. , vehicle speed V
The information is added to a speed classification circuit, which classifies the vehicles according to their speed, and uses the output to operate a counter to count the number of vehicles. However, with such a vehicle sensor, there is no problem in the case of a two-axle vehicle, and in the case of a three-axle vehicle, l>Cl (Cl is the vehicle's However, as shown in Figure 2b, if l<Cl, the wheelbase distance between the front and center axles of a 3-axle vehicle is In other words, it is determined that it is a two-axle vehicle with an inter-axle distance Dl,
Furthermore, the last wheel is incorrectly detected as the front wheel of a new car following. Therefore, the conventional example has the disadvantage that accurate vehicle identification is impossible when l<Cl.
Further, there are restrictions on the installation of wheel detectors such as tape switches and rubber hose switches, and for example, the distance between tape switches must be longer than the distance between axles. In view of the above points, the present invention has been made to solve such problems and eliminate such drawbacks.The purpose of the present invention is to accurately determine the number, speed, and type of vehicles with different numbers of axles. The object of the present invention is to provide a vehicle sensor that can In order to achieve such an objective, the present invention
a first wheel detector installed on a road to detect passing of a vehicle wheel and output a first detection signal; and a rear wheel of a first vehicle of two vehicles passing successively. When the minimum distance between the front wheels of the first vehicle is L, the first vehicle detector is installed on the road at a predetermined distance l (<L) in the direction of travel of the vehicle, and
a second wheel detector that detects passage of a vehicle wheel and outputs a second detection signal; and a second wheel detector that performs a timekeeping operation based on the output of the first detection signal and starts a new timekeeping operation for each output and resets the timer. When the signal is input, the first timer returns to the timekeeping start state, starts the timekeeping operation by outputting the first detection signal, and stops the timekeeping operation by outputting the second detection signal, and returns to the timekeeping start state. Return to and add a second timer to measure and output the time tv between when both signals are output, and a timer
means for measuring and outputting vehicle speed V (=l/tv) from tv and a predetermined distance l; means for determining and outputting time T (=L/V) from vehicle speed V and minimum interaxle distance L; Time to (=T−
tv), starts timing by outputting the second detection signal, and outputs a reset signal for the first timer after time to; The vehicle type is determined by verifying the front and rear wheels and calculating the axle distance based on the number of first detection signal outputs input to the timer 1 and the time between the signals. Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Figure 3 shows the installation interval l of wheel detectors A and B in the vehicle sensor according to the present invention and the minimum distance between the axles of the first front wheel and the second rear wheel of the first and second vehicles. This is an explanatory diagram for explaining the relationship with L.
<L is set. Note that Cl indicates the axle distance, and the arrow indicates the traveling direction of the vehicle. FIG. 4 is a block diagram showing an embodiment of the vehicle sensor according to the present invention, and only the parts necessary for explanation are shown. In Fig. 4, the same reference numerals as in Fig. 3 indicate corresponding parts, and DET ₁ and DET ₂ are the first and second wheel detectors activated by the outputs of the first and second wheel detectors A and B, respectively. In the input detection circuit, the output of this first input detection circuit DET ₁ is connected to the first timer circuit.
It is connected to the input side of the second timer circuit TM ₁ and also connected to the input side of the second timer circuit TM ₂ .
The output of the input detection circuit DET ₂ is connected to the input side (reset terminal) of the second timer circuit TM ₂ ,
The second timer circuit _TM2 is configured to be reset. CSM is a vehicle speed measurement circuit that uses the output of the second timer circuit TM ₂ as input to measure the vehicle speed, and its output is introduced into the input side of the minimum distance measurement circuit MCSM and is configured to be output OUT. .
The minimum inter-vehicle distance measuring circuit MCSM then calculates the minimum inter-axle distance L based on the input from the vehicle speed measuring circuit CSM.
It is configured to measure the time it takes for the vehicle to pass through. TM ₃ is a third timer circuit which inputs the output of the minimum distance measuring circuit MCSM and measures the required time from the detection output of _the vehicle detector B based on this input. Therefore, the first timer circuit _TM1 is configured to be reset. CWM is a wheel measurement circuit that uses the output of the first timer circuit TM ₁ as an input to verify the front and rear wheels of the vehicle, CWAM is an axle measurement circuit that uses the output of the wheel measurement circuit CWM as input and measures the axle distance, and CKD is a This is a vehicle type determination circuit that receives the output of the axle measurement circuit CWAM and determines the vehicle type based on pre-stored data on vehicle type and axle distance. And OUT
indicates the output. Next, the operation of the embodiment shown in FIG. 4 will be explained with reference to FIG. In Fig. 5, a shows a time chart when the axle is "2", that is, a regular passenger car, and b shows a time chart when the axle is "3", that is, a large truck,
This shows a time chart for a bus. And, A and B indicate the outputs detected by the first and second wheel detectors A and B, respectively, F is the pulse obtained by the front wheels of the vehicle,
R indicates the pulse obtained by the rear wheels of the vehicle.
Further, , , indicate the manner in which time is measured by the first, second, and third timer circuits TM ₁ , TM ₂ , and TM _{3 ,} respectively. First, the spacing between the wheel detectors A and B is set so that the installation spacing l of the wheel detectors A and B and the minimum interaxle distance L shown in FIG. 3 satisfy the condition l<L.
Here, the axle distance between the front wheel axle and rear wheel axle of a vehicle is generally 5.4 m for large vehicles, so the minimum axle distance L
may be considered to be larger than this, for example 6 m. That is, this device is designed on the assumption that the distance between the rear wheel axle of the front vehicle and the front wheel axle of the rear vehicle is close to 6 m or less, for example, so that the two vehicles do not run consecutively. Therefore, the distance l between vehicle detectors is, for example, 6 m.
Set to any distance below. Then, when the vehicle passes the first wheel detector A, that is, when the front wheel of the vehicle steps on the tape switch of the first wheel detector A, the first trigger of A shown in FIGS. generates an eye pulse F, which activates the first input detection circuit DET 1, detects the front wheel of the vehicle and detects the first input detection circuit DET ₁ .
and second timer circuits TM ₁ and TM ₂ respectively operate. Here, this first timer circuit
TM ₁ and the second timer circuit TM ₂ operate independently,
Measure each until the next input is received. Then, the first timer circuit _TM1 resets the measured time based on the input condition and the reset condition of the third timer circuit _TM3 , and stores the measured time. Next, the vehicle passes the second wheel detector B, i.e. the front wheels of the vehicle pass the first wheel detector A.
For example, if you step on the tape switch of the second wheel detector B, then the tape switch of the second wheel detector B will be turned on.
A first pulse F of B shown in b is generated, which activates the second input detection circuit _DET2 , and its output resets the second timer circuit _TM2 . And this second timer circuit
The measured time of TM ₂ is the time tv from the first pulse F of A to the first pulse F of B (Fig. 5a,
b) is determined, and the vehicle speed V is measured from the installation interval distance l of the first and second wheel detectors A and B using the vehicle speed measuring circuit CSM as shown in equation (4) below. V=l/tv...(4) Then, the output of this vehicle speed measurement circuit CSM is introduced into the next stage minimum distance measurement circuit MCSM, and
The output is OUT. After measuring the vehicle speed V in this manner, the minimum distance measuring circuit MCSM calculates the time T required for the vehicle to pass through the axle distance between the vehicles (minimum inter-axle distance L) as shown in equation (5) below. T=L/V...(5) Here, since the axle distance of a vehicle is shorter than the axle distance between vehicles, the passing time from the front wheel to the rear wheel is the axle distance between the vehicles, that is, after the first vehicle. This is shorter than the passing time T of the axle distance from when the wheels pass until the front wheels of the second vehicle pass. After measuring the minimum distance in this way, the third
The second timer circuit TM ₂ is activated based on the transit time T of the axle distance between the vehicles _.
The value obtained by subtracting the measured time tv, that is, the time T-tv, that is, the front wheel resets itself a certain period of time after stepping on the tape switch of the second wheel detector B, and outputs a reset signal. . Then, after the third timer circuit _TM3 finishes timing this fixed period of time, the first timer circuit _TM1 is reset by its output. That is, after a certain period of time to, the last clock of A is turned off, and the start of the last clock becomes the final wheel. In this way, the total time up to the reset count time before _the reset signal of the third timer circuit _TM3 is determined from the time counted by the first timer circuit TM1. That is, in the case of a two-axle vehicle, the time (t ₁ ) is determined from the time chart shown in FIG. 5a, and in the case of a three-axle vehicle, the time (t _{1 )} is determined from the time chart shown in FIG. 5b.
+t ₂ ). Then, the vehicle axle distance Cl is determined by the following equation (6). Cl=V・t (6) However, t is t ₁ for a two-axle vehicle, and t ₁ +t ₂ for a three-axle vehicle. Next, the relationship between the axle distance Cl and the vehicle type is as follows:
The results are as shown in Table and Table 2.

【table】 That is,

[Table] The axle distance for the vehicle type obtained in this manner is stored, and the vehicle type is determined from the measured value. That is, the front wheels and rear wheels of the vehicle are verified by the wheel measurement circuit CWM, and the axle measurement circuit
The axle distance is calculated by CWAM, and the vehicle type is determined by the vehicle type determination circuit CKD. After determining the vehicle type, the number, speed, and vehicle type are output.
Go out. In this way, it is possible to accurately determine the type of vehicle for different types of vehicles, and also to accurately detect the number and speed of the vehicles. Although the present invention has been described above with reference to the case where it is applied to a two-axle vehicle and a three-axle vehicle, the present invention is not limited thereto, and can be applied to a multi-axle vehicle having three or more axles, such as a four-axle vehicle. It can also be applied to 3-axle vehicles in the same way. As explained above, according to the present invention, the minimum axle distance between vehicles is determined in advance, and by focusing on the fact that the axle passing time of the vehicles is shorter than the time it takes to pass through the distance, the front and rear wheels of vehicles with different axles are Since the system detects the vehicle type and uses the axle distance to determine the vehicle type, it is possible to easily and accurately distinguish between different vehicle types, and also accurately detect the speed and number of vehicles. Because it is possible to
The practical effects are extremely large. It is also extremely effective in that there are no restrictions on the installation of the wheel detector.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining the principle of an example of a conventional vehicle sensor, FIG. 2 is an explanatory diagram for explaining the operation of the conventional example, and FIG. 3 is an explanatory diagram for explaining the principle of a vehicle sensor according to the present invention. FIG. 4 is a block diagram showing one embodiment of the present invention, and FIG. 5 is a time chart for explaining the operation of the embodiment shown in FIG. A, B...Wheel passing detector, TM ₁ to TM ₃ ...Timer circuit, CSM...Vehicle speed measurement circuit, MCSM...Minimum distance measurement circuit, CWM...Wheel detection circuit, CWAM
...Axle measurement circuit, CKD...Vehicle type determination circuit.

Claims (1)

[Claims] 1. A first wheel detector A that is installed on a road and detects the passage of a vehicle wheel and outputs a first detection signal.
And, when L is the minimum distance between the rear wheels of the first vehicle and the front wheels of the second vehicle of two vehicles passing successively, the traveling direction of the vehicle is determined from the first vehicle detector. a second wheel detector B, which is also installed on the road at a predetermined distance l (<L) away from and outputs a second detection signal by detecting passage of a vehicle wheel; and output of the first detection signal. A first timer (TM ₁ ) that performs a timekeeping operation and starts a new timekeeping operation for each output, and returns to the timekeeping start state when a reset signal is input; a second timer (TM ₂ ) that starts the time measurement operation, returns to the time measurement start state by outputting the second detection signal, and measures and outputs the time tv during which both signals are output; A means (CSM) for measuring and outputting the vehicle speed V (=l/tv) from the time tv counted by the second timer and a predetermined distance l, and a time T (=
A means (MCSM) to obtain and output L/V), and a time to (=T-tv) which is obtained by subtracting time tv from time T.
A third timer (TM 3 ) which starts timing by outputting the second detection signal and outputs a reset signal for the first timer after time to, and a third timer (TM ₃ ) which starts timing by outputting the second detection signal and outputs a reset signal to the first timer until the reset signal is input to the first timer. means (CWM, CWAM, Vehicle detector with CKD).