JPS6055283A - Method for detecting car - Google Patents

Abstract

PURPOSE:To adjust the sensitivity of a passing car detecting loop coil automatically by controlling the threshold of detecting levels on the basis of the average value of plural cars. CONSTITUTION:When a car passes through the loop coil 1, its inductance is changed, the changed value is detected by a changed value processing part 2 and the detected result is supplied to a signal processing part 6. The processing part 6 decides the kind of an automobile or the like from the detected result pattern, calculates the average value of the detected results of the fixed number of cars belonging to the same kind to control the threshold of the detecting levels in the coil 1. Even if the sensitivity of the coil 1 is changed, the sensitivity is automatically corrected, so that it is unnecessary to stop the car and adjust the sensitivity of the loop 1 manually every fixed period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a vehicle detector in which a loop coil is buried in a road and the inductance of the loop coil changes as the vehicle passes on the road, thereby detecting the passing of a vehicle. The present invention relates to a vehicle detection method using a vehicle detection method.

The detection level setting of a vehicle detector using a loop coil as described above varies depending on the depth of burial of the loop coil, the presence of metal objects near the loop coil, etc. Furthermore, sensitivity deterioration occurs due to aging of the signal processing section of the detector body.

Therefore, it is necessary to perform periodic inspections at regular intervals and to perform periodic corrections.

FIG. 1 shows a conventional vehicle detector, in which 1 is a detecting section such as a loop coil, 2 is a variation processing section, 3 is a level detecting section, 4 is an output section, and 5 is provided in the level detecting section 3. This is the both value setting section.

Adjustment and maintenance of the above device is performed as follows.

A metal plate or a loop coil serving as a simulated vehicle body is placed on a loop coil serving as a detection unit 1 buried in the road, and the detection setting unit 5 is adjusted so as to detect at a fixed position.

However, such conventional methods have problems such as the need to shut off road traffic during adjustment, and the sensitivity adjustment being performed by humans, which is complicated and requires skill.

This invention was made to solve the problems of the conventional vehicle detection method as described above, and it averages the amount of change in the inductance of the loop coil due to a certain number of vehicles passing on the road. It is an object of the present invention to provide a method for automatically adjusting the sensitivity d14 by controlling the 1 value of the detection level.Hereinafter, the method of the present invention will be explained based on FIG. 2.

The detection unit, 11 change amount processing unit 2, and output unit 4 in FIG.
Although it is the same as the apparatus shown in the figure, a signal processing section 6 is provided between the change amount processing section 2 and the output section 4.

This signal processing section 6 has the functions of detecting the amount of change in inductance when a vehicle passes, detecting a pattern of changes in the inductance, detecting a peak value, and averaging processing, and also has a storage section and an output processing section. ing.

The pattern of the amount of change in inductance occurring in the detection unit l differs depending on the shape of the vehicle passing on the road.

Therefore, by detecting the pattern using the signal processing section 6, the type of vehicle can be determined. For example, focusing only on the amount of change in inductance of the type of passenger car,
By averaging the peak values of only a certain pattern and using that value to determine the duty value of the Kude level, it is possible to automatically correct for changes in sensitivity after setting. In addition to the method of setting both values of the detection level based on the pattern of only a specific vehicle, as in the case of the passenger car in the above embodiment, the average processing value of the peak value of the detection pattern of all vehicles, or the method of setting only the detection level value equal to or higher than the specific level value of all vehicles. There are also methods that target this, but these also belong to the technical scope of this invention.

As described above, this invention averages the amount of change in the inductance of a fixed number of vehicles passing over the loop coil, and automatically controls the sensitivity by 1u (detected by 11) MF, so if the detection sensitivity is initially set at the time of setting, manual adjustment is not required thereafter.

Therefore, there is no need to stop traffic and perform periodic inspections and adjustments as in the past. There is iJ fruit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional vehicle detection device, and FIG. 2 is a block diagram of a vehicle detection device implementing the method of the present invention. l...Detection section, 2...Change amount processing section, 4...Output section, 6...Signal processing section Patent applicant Sumitomo Kameki Industries Co., Ltd. agent Patent attorney Kazu 1) Akira

Claims (1)

[Claims] In a vehicle detection method that detects the passing of a vehicle by a change in the inductance of a loop coil, the amount of change in the inductance of the loop coil is averaged over a certain number of vehicles, and the detection level □ value is controlled by that value. A vehicle detection method characterized by: