JPS63237198A - Vehicle type discriminator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vehicle type discrimination device that detects the height of a vehicle using ultrasonic waves and discriminates the type of vehicle.

Conventional technology Conventionally, this type of vehicle type identification device was disclosed in Japanese Patent Application Laid-open No. 59-1435.
As described in Publication No. 56, an ultrasonic head that emits ultrasonic waves at a predetermined cycle, an ultrasonic vehicle detector that detects passing vehicles using reflected waves from the road surface and passing vehicles, and Vehicle height calculation means for calculating the height of the vehicle based on the response time of the reflected wave detected by the sonic vehicle sensor;
The vehicle type determining means is configured to determine the vehicle type based on the vehicle height calculated by the vehicle height calculating means.

As shown in FIG. 4, the ultrasonic head 1a is installed above the road surface E, transmits ultrasonic waves in the direction of the road surface E, and has a sensing area WL for receiving reflected waves, and a vehicle V1 located within this area. , V2 and the response time of the reflected waves from the road surface E are detected.

The vehicle height calculation means calculates the longest response time of the reflected wave as the response time of the reflected wave from the road surface, and calculates the shortest response time as the response time of the reflected wave from the vehicle, in order to correspond to the speed of the ultrasonic wave depending on the temperature. The vehicle height is calculated based on these two response times.

Problems to be Solved by the Invention However, in the conventional vehicle type identification device described above, as shown in FIG. If vehicle v2 is continuously located within the sensing area, it is not possible to measure the response time from the road surface, which is the basis for calculating the vehicle height, and therefore the vehicle type cannot be determined in this case. There is a problem.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a vehicle type discrimination device that can accurately discriminate the vehicle type even when power is restored.

Means for Solving the Problems In order to solve the above problems, the present invention sets the response time of reflected waves from the road surface in advance, and adjusts the response time of the reflected waves from the vehicle sensing means and the set response time. If the response time of the reflected wave from the vehicle sensing means is small, the set response time is determined as the response time of the reflected wave from the road surface, and the response time of the reflected wave from the vehicle sensing means is not small. In this case, the response time of the reflected wave from the vehicle sensing means is determined as the response time of the reflected wave from the road surface.

According to the above configuration, when the vehicle is located within the sensing area of the ultrasonic head when the power is restored, and when the following vehicle is located within the sensing area continuously, the set response time is Since it is determined as the response time of reflected waves from the road surface, the vehicle type can be accurately determined even when power is restored.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing an embodiment of the vehicle type discrimination device according to the present invention, FIG. 2 is an explanatory diagram of how the vehicle type calculating section of FIG. 2 is a flowchart for explaining the operation of the vehicle type discrimination device shown in the figure, particularly the vehicle height calculation section.

In FIG. 1, 1a is an ultrasonic head installed above the road surface E, which transmits ultrasonic waves at a predetermined period in the direction of the road surface E and receives reflected waves. It has a sensing area of

1 is an ultrasonic vehicle that senses a vehicle V passing on a road surface E by sequentially outputting a time difference between the ultrasonic head 1a transmitting an ultrasonic wave and receiving a reflected wave, that is, a response time at the above-described predetermined cycle. It is a sensor.

2 has a storage means in which the response time To of the reflected wave from the road surface E is set in advance according to the height H of the ultrasonic head 1a and the current temperature, and the response time To from the vehicle sensor 1 is stored as described later. This is a vehicle height calculation unit that calculates vehicle height based on time.

Reference numeral 3 denotes a vehicle type discrimination section that discriminates the vehicle type based on the vehicle height from the vehicle height calculation section 2. In the vehicle type discrimination section 3, vehicle types corresponding to the vehicle height are registered in advance.

Next, the vehicle height calculation method of the vehicle height calculation section 2 will be explained with reference to FIG.

As shown in FIG. 2, when the height of the ultrasonic head 1a from the road surface E is H1, the response time from the vehicle V is t1, the response time from the road surface E is T, and the speed of the ultrasonic wave is C: The height h of the vehicle V can be calculated using the following formula % formula % (1). Here, since the speed C depends on the temperature, the speed C is C= 2 H/T (2), and substituting equation (2) into equation (1) , h=H(1-(t/T
))...(3), and the height h of the vehicle V can be calculated using equation (3) that does not depend on the temperature.

Next, referring to FIG. 3, an embodiment according to the above configuration, particularly the operation of the vehicle height calculating section 2, will be described.

In step 11, when the ultrasonic vehicle sensing section 1 outputs the measured response time τ to the vehicle height calculation section 2, the vehicle height calculation section 2, in the following step 12, responds to the measured response time or the response set in the storage means. Is it not smaller than time TO (τ
≧To).

If τ≧To, the process proceeds to step 13, where the measured response time τ is determined as the response time T due to reflection from the road surface E.

On the other hand, in step 12, if τ≧To is not true, the process branches to step 14, where it is determined that the measured response time τ is not the response time from the road surface E, and the response time To in the storage means is set as the response time due to reflection from the road surface E. Find it as T.

Therefore, as shown in FIG. 4, when the power is restored, the vehicle v
1, ■2 is located within the sensing area of the ultrasonic head la,
Furthermore, even when the following vehicle v2 is continuously located within the sensing area, the response time T from the road surface, which is the reference for calculating the vehicle height, can be determined.

The vehicle height calculation unit 2 then obtains the response time from the vehicle V by obtaining the minimum value of the measured response time τ, and calculates the response time from the vehicle V by calculating the above equation (3
), and outputs the calculated vehicle height to the vehicle type determination section 8.

The vehicle type determination unit 3 determines the vehicle type based on the vehicle height and the vehicle type registered in advance according to the vehicle height.

Therefore, according to the above embodiment, even when vehicles pass successively when the power is restored, each vehicle type can be accurately identified, and the calculation formula (3) can be used to accurately identify the vehicle type regardless of the temperature. can be determined.

In the above embodiment, the ultrasonic vehicle sensor 1, vehicle height calculation section 2, and vehicle type determination section 3 were explained as separate structures.
A central processing unit (CPU), a read-only memory (ROM) that stores CPU execution programs, and a power supply backup in case of a power outage etc. Calculation formula (3)
The constants used for C and the vehicle type according to the vehicle height are stored.
Random access memory (with PU work area, etc.)
Of course, it is possible to configure a larger number of RAMs.

Note that a nonvolatile memory may be used instead of the RAM.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention sets the response time of the reflected wave from the road surface in advance, compares the response time of the reflected wave from the vehicle sensing means with the set response time, and detects the reflected wave from the vehicle sensing means. When the response time of the reflected wave from the vehicle sensing means is small, the set response time is determined as the response time of the reflected wave from the road surface, and when the response time of the reflected wave from the vehicle sensing means is not small, the response time from the vehicle sensing means is determined. Since the configuration is configured such that the response time of the reflected wave from the road surface is determined as the response time of the reflected wave from the road surface, the vehicle type can be accurately determined even when the power is restored.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the vehicle type discrimination device according to the present invention, FIG. 2 is an explanatory diagram of how the vehicle type calculating section of FIG. A flowchart for explaining the operation of the vehicle type discrimination device shown in the figure, particularly the vehicle height calculation section,
FIG. 4 is an explanatory diagram for sensing a vehicle. la...Ultrasonic head, 1...Ultrasonic vehicle sensor, 2...Vehicle height calculation section, 8...Vehicle type discrimination section, V, Vl
, V2-0° vehicle, E...road surface. Name of agent: Patent attorney Toshio Nakao and 1 other person
2 rM Figure 3 Figure 4 (A) (B) Sensing kite

Claims (2)

[Claims] (1) An ultrasonic head that is installed above the road surface, transmits ultrasonic waves in the direction of the road surface at a predetermined period, and receives reflected waves from the road surface and vehicles on the road surface; and reflected waves received by the ultrasonic head. a vehicle sensing means that detects the vehicle's position on the road surface by detecting the response time of the vehicle; a memory means in which the response time of the reflected wave from the road surface is set in advance; means for calculating the response time of the reflected wave from the vehicle based on the shortest response time, and comparing the response time of the reflected wave from the vehicle sensing means with the response time of the storage means, and calculating the response of the reflected wave from the vehicle sensing means. If the time is small, the vehicle height is calculated based on the response time of the storage means and the response time of the reflected wave from the vehicle, and when the response time of the reflected wave from the vehicle sensing means is not small, the vehicle height is calculated by the vehicle height. vehicle height calculating means comprising means for calculating a vehicle height based on a response time of a reflected wave from the vehicle and a response time of a reflected wave from the vehicle; and means for determining a vehicle type based on the vehicle height calculated by the vehicle height calculating means. A vehicle type identification device comprising: (2) The vehicle type discrimination device according to claim 1, wherein the vehicle height calculation means calculates the vehicle height using a calculation formula that does not depend on temperature.