JPH02281147A - Mat type vehicle-speed measuring apparatus - Google Patents

Abstract

PURPOSE:To facilitate the arrangement of sensors and to make it possible to measure the speeds of a plurality of vehicles at the same time by arranging a mat part over which the vehicles pass. CONSTITUTION:In a mat-type sensor part 1, the following parts are formed in a sandwich pattern with a specified width: a flexible conductive sheet; non- conductive elastomer; conductive rubber whose electric resistance changes with the amount of strain; and the like. The sensor part 1 detects the axial loads of the vehicles and the like. The capacitance or the electric resistance changes in response to the axial load. A data processing part 2 amplifies a load signal 10a in response to the change in capacitance or the change in resistance. Then A/D conversion is performed. A peak value 10b of the load signal 10a is measured with a microprocessor and the like. A measured time T1 of vehicle passage indicating a 1/2 value 10c or more of the peak value 10b is measured. The vehicle speed is operated automatically. A display device 3 visually displays the output signal from the processing part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a mat-type vehicle speed measuring device for measuring the speed of a vehicle traveling all over a road.

[Conventional technology]

Conventionally, as a means of measuring the speed of a vehicle, a means for measuring the time it takes for a vehicle to pass between two photoelectric switches arranged in parallel, a microwave transmitting and receiving device are provided, and the frequency of the received microwave is measured. The means etc. are provided.

[Problem to be solved by the invention]

The above conventional means of measuring vehicle speed is a non-contact measuring means, and in the case of means using photoelectric switches, the distance between two photoelectric switches is determined accurately, and the optical axes of both photoelectric switches are made parallel. Because it has to be installed,
Careful attention was required for installation. Furthermore, if another vehicle or the like enters the vehicle that is attempting to measure the photoelectric switch and vehicle speed, it becomes impossible to measure the vehicle speed.

On the other hand, methods using microwaves emit microwaves from the front or rear of the vehicle to be measured, and it is necessary to measure from a certain distance or more. If there was a vehicle that did so, it was impossible to measure.

It is an object of the present invention to provide a mat-type vehicle speed measuring device which eliminates the above-mentioned drawbacks, facilitates the arrangement of sensors, and enables simultaneous measurement of the vehicle speeds of a plurality of vehicles.

[Means to solve the problem]

In order to achieve the above object, the present invention uses a mat-type sensor that detects a load as a sensor that measures the speed of a vehicle.

That is, a mat type sensor section 1 that can measure the axle load of an automobile etc. under a normal paved road environment and a load signal 10a from the mat type sensor section 1 are input, and the peak value 10
a data processing unit 2 that measures the passing speed of the vehicle by measuring the time when the 1/2 value of b is 10c or more;
It is comprised of a display device 6 that displays vehicle travel.

[Effect]

The mat type sensor section 1 is a flexible conductive sheet 5a.

5b, a non-conductive elastomer 6a, a conductive rubber 6b whose electrical resistance changes depending on the amount of strain, etc. are formed in a sandwich shape with a certain width to detect the axle load of an automobile etc. Capacitance or electrical resistance changes.

The data processing unit 2 amplifies the load signal 10a corresponding to the change in the capacitance or resistance of the mat type sensor unit 1, and
/D conversion, the peak value 10b of the load signal 10a is measured by the microprocessor 4, etc., the vehicle passing measurement time T1 in which the peak value 1ob is 1/2 value 10c or more is measured, and the vehicle speed is automatically calculated. . The display device 6 visually displays the output signal from the data processing section 2. As described above, in the present invention, the speed of the vehicle is measured using the mat type sensor section 1 that detects the axle load of the vehicle.

〔Example〕

One embodiment will be described in detail below based on the drawings.

FIG. 1 shows a block diagram of a mat type vehicle speed measuring device according to the present invention. The mat type sensor section 1 has a capacitance or electrical resistance that changes in response to the axial load of an automobile or the like, and outputs a voltage corresponding to the axial load upon input from an external power source. The output signal from the mat type sensor section 1 is input to a data processing section 2 where it is amplified, A/D converted, and arithmetic processed, and the speed of the vehicle passing over the mat type sensor section 1 is calculated. The data calculated by the data processing section 2 is input to the display device 6 and displayed so that the speed of the vehicle can be visually recognized. FIG. 2a shows an embodiment of the mat type sensor section 1. FIG. The mat type sensor part 1 is composed of two conductive sheets 5a and 5b and a non-conductive elastomer 6a spaced between the conductive sheets 5a and 5b, and a mat part 4a forming a capacitor and a high precision The mat portion 4 is composed of a bridge circuit 4b formed with a resistance wire and a high frequency power source 4c input to the bridge circuit 4b.
a is connected in parallel to the resistance wire forming the bridge circuit 4b.

FIG. 2 shows another embodiment of the mat type sensor section 1. As shown in FIG.

The mat portion 4a has a conductive rubber 6b whose resistance value changes depending on the amount of strain, sandwiched between two conductive sheets 5a5b,
It constitutes one resistor of the bridge circuit 4b. Other Figure 2a
The same symbol indicates the same name. In addition, in FIG. 2 a%b, the mat portion 4a has a certain width, for example, 800 mm.
It forms a single sheet with a width comparable to that of a fin, and the output voltage of the mat type sensor section 1 increases as the area of the wheel mounted on the upper surface of the mast section 4a and the shaft load increase.

The output voltage from the mat type sensor section 1 is input to the data processing section 2 shown in FIG. The data processing section 2 is an amplification section 11 that amplifies the output voltage from the mat type sensor section 1.
, an A/D conversion circuit 12 that digitally converts the output of the amplifier 11, and a voltage of a delay circuit 20 that delays the output signal of the A/D conversion circuit 12 by one pulse and outputs the output signal. The output signal of the A/D conversion circuit 12 at this time is determined by detecting that the maximum value measurement circuit 16 and the maximum value identification circuit 13, which detect the maximum value by detecting the increase or decrease, detect O or minus. a maximum value measurement circuit 14 that outputs the maximum value measurement circuit 14 as it is, and a 1/2 calculation circuit 15.1/2 that inputs the output signal of the maximum value measurement circuit 14 and stores the calculation in 1/2.
The value of the arithmetic circuit 15 is compared with the output signal of the memory circuit 16 which stores the output signal of the A/D conversion circuit 12 for a certain period of time, and 1
/2 A time measuring circuit 17 that multiplies the number of pulses of the output signal of the memory circuit 16 that indicates a value equal to or higher than the value of the arithmetic circuit 15 and measures the time that indicates 1/2 of the maximum value. It is known that the time represents approximately 70% of the time required for the wheel to pass over the mat portion 4a. On the other hand, when the wheel passes over the manometer part 4a, the output signal of the mat type sensor part 1, which indicates the start and end, is easily disturbed and it is difficult to obtain an accurate value.
A means for measuring the time when an output of /2 or more is obtained is easier to calculate and can be said to be more accurate. The output signal of the time measurement circuit 17 is input to the speed calculation circuit 18, where, for example, ■ is the vehicle speed to be determined, T is the time indicating an output of 1/2 or more of the maximum value measured by the time measurement circuit, and Ll indicates the width of the sensing portion of the mat portion 4a, and L2 indicates the contact length of the wheel.

The output signal of the speed calculation circuit 18 is input to the display device B,
For example, it is visually recognized as a numerical display. Display device 6
It is composed of a display 21 and a display conversion circuit 22 that converts and outputs the output signal of the speed calculation circuit 18 to the display 21 in order to properly output it to the display 21.

The mat type sensor section 1 also serves as a load measurement sensor, and by providing a load measurement circuit within the data processing section 2, it is possible to measure vehicle speed and load at the same time.

〔Effect of the invention〕

According to the present invention, since the sensor can be positioned on the road by simply installing it on the mat portion 4a' at a position where a vehicle passes, almost no adjustment is required in installing the sensor. In addition, since the vehicle speed is measured by directly receiving the load when the vehicle passes over the mat section 4a, even if several vehicles are running side by side, the mat section 4a Only the running speed of vehicles traveling on 4a is measured, which has the effect of allowing measurements to be taken without confusion.

[Brief explanation of drawings]

FIG. 1 is a block explanatory diagram according to the present invention, FIG. 2 is an explanatory diagram of a mat type sensor section according to the present invention, and FIG. 3 is an explanatory diagram of one embodiment of a data processing section.

Claims (1)

[Claims] A mat-type sensor unit that can measure the axle load of an automobile, etc. under a normal paved road environment, and a load signal from the mat-type sensor unit is input, and the time at which the load signal reaches 1/2 or more of the peak value is measured and processed. What is claimed is: 1. A mat-type vehicle speed measurement device comprising: a data processing section that measures the passing speed of a vehicle; and a display device that displays vehicle speed.