JPH03120494A - Road surface state detecting method - Google Patents

Abstract

PURPOSE:To accurately judge a road surface state by comparing the inter- electrode resistance value of a 1st detecting element which has no heating means for an insulator between a couple of electrode with that of a 2nd detecting element which has a heating means. CONSTITUTION:A voltage is applied between the outside and inside electrodes 11 and 21, and 12 and 22 of the 1st and 2nd detecting elements 1 and 2 and electricity is fed even to the heater 4 in the insulator 32 between the couple of electrodes of the detecting element 2. The resistance between the electrodes 11 and 12 of the detecting element 1 is high when the road surface 6 is dry or when there is ice or snow and low when the road surface is merely wet. The detecting element 2, on the other hand, is equipped with the heater 4, so the resistance between the electrode 21 and 22 is high only when the road surface 6 is wet and increases faster than the detecting element 1 when the wet road surface 6 begins to become dry. Therefore, the inter-electrode resistances of the detecting elements 1 and 2 are compared with each other to accurately judge the state of the road surface 6 from a combination of a high-resistance case and a low-resistance case.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for detecting whether a road surface is dry, wet, or frozen, and particularly relates to a method for detecting whether a road surface is dry, wet, or frozen. The present invention relates to a road surface condition detection method useful for road surface control.

[Prior Art] In order to prevent roads from freezing, methods such as burying heating cables in a meandering manner under the road surface are used in cold regions to melt ice and snow on the road surface. In this case, if the heating cable is constantly energized, the driver may be used to inefficient driving, such as heating a dry road surface. It is used as a road heating system, which is configured to heat the road surface when necessary.

Conventionally, a road surface condition detection device 7 as shown in FIG. 3 has been used as a device for detecting the above-described road surface condition. FIG. 4 is a sectional view showing the device 7 installed on a road surface 60. The device 7 includes an outer electrode 71 and an inner electrode 72 made of metal cylinders arranged concentrically, an insulator 8 such as epoxy filled in the inner peripheral side of the outer electrode 71 to insulate between the electrodes, and an insulator. A heater 9 is embedded in a predetermined position within the heater 8. Note that 73 is a bottom plate attached to the bottom surface of the outer electrode 71, and 50 is a lead wire for feeding power to the electrode. The upper surfaces of the outer electrode 71 and the inner electrode 72 are each exposed to the outside, and as shown in FIG. 4, these electrode exposed surfaces and the road surface 60 are substantially flush with each other and are buried underground.

The operation of the road surface condition detection device 7 will be explained. First, a voltage is applied between the outer electrode 71 and the inner electrode 72, and the electrical resistance between the electrodes is measured.

Here, when the road surface 60 is dry (that is, when the electrode exposed surface of the device 7 is dry), the electrode resistance between the outer electrode 71 and the inner electrode 72 is extremely high, and the road surface 60 is wet. If there is water, the presence of water brings the electrical resistance between these electrodes into a conductive state.

By monitoring the electrical resistance between the outer electrode 71 and the inner electrode 72, the surface condition of the road surface 60 can be determined. The heater 9 is provided so that when the road surface 60 is frozen or snowing, the ice or snow is melted into water by heat to make it easier to see the decrease in the resistance between the electrodes. (If the heater 9 is covered with water, the inter-electrode resistance will not decrease much unlike in the case of water), and the heater 9 is always kept energized.

[Problems to be Solved by the Invention] However, the method of detecting the road surface condition using the road surface condition detection device 7 as described above has the following problems. In other words, ■ Since it is a method in which ice and ice on the road surface are melted by the heater 9 and detected as moisture,
It is not possible to determine whether the road surface is frozen (snowy) or simply wet; in other words, it is only possible to determine whether the road surface is dry or not, which is insufficient information to control the road heating system. be.

■ The outer electrode 71 and the inner electrode 72 are heated by the built-in heater 9.
Since the insulator 8 between the electrodes is always kept in a heated state, the transition time from a wet state to a dry state is faster between the electrodes than on the road surface, and therefore it is not possible to accurately judge the state of the road surface. be.

The present invention has been devised to solve the above-mentioned disadvantages, and provides a method that can determine whether the road surface is frozen, wet, or dry, and can accurately determine the road surface condition. The purpose is to

[Means for Solving the Problems] The road surface condition detection method of the present invention includes a pair of electrodes that are partially exposed above the ground surface and arranged substantially flush with the ground surface, and an insulator between the electrode pairs. A first detector and a second detector similarly equipped with an electrode pair and an inter-pair insulator and having means for heating the inter-pair insulator are provided on the road surface, and the first and second detection elements are provided on the road surface. It is characterized by measuring the resistance between the electrodes of each child and comparing these measured resistance values to determine the road surface condition.

[Function] Since the first detector is not equipped with a means for heating the insulator between the electrode pairs, the resistance between the electrodes decreases when the road surface is dry or there is ice or snow. higher, and lower resistance if simply wet. On the other hand, in the second detector, since the inter-pair insulator heating means is provided, the inter-electrode resistance becomes high only when the road surface is dry.

Therefore, by comparing the inter-electrode resistances of the first and second detectors, it is possible to understand the road surface condition from the combinations of cases where the inter-electrode resistance of each detector is high resistance and low resistance. can.

[Example] An example of the present invention will be described in detail below based on the drawings.

FIG. 1 is a plan view showing an example of the road surface condition detection bag MS used in the road surface condition detection method of the present invention, and FIG. 2 is a plan view of the device S.
FIG.

The road surface condition detection device S includes a first detector 1 that includes an outer electrode 11 and an inner electrode 12 made of metal cylinders arranged concentrically, and an inter-pair insulator 31 made of epoxy or the like that insulates between these electrode pairs. Similarly, it is equipped with an outer electrode 21, an inner electrode 22, and an inter-pair insulator 32, and is also provided with an electric heater 4 for heating the inter-pair insulator 32 embedded in the inter-pair insulator 32. It consists of a second detector 2. Note that 5 is a lead wire for supplying power to each electrode of the first and second detectors 1.2 and the heater 4, and 13.23 is a lead wire attached to the bottom of each outer electrode 11.12. This is the bottom plate that is worn.

The peripheral edges of both the outer electrode 11 and the inner electrode 12 of the first detector 1 are exposed to the outside, and the exposed surfaces of the electrodes, including the interpair insulator 31, are cut into flat surfaces. Similarly, in the second detector 2, both the outer electrode 21 and the inner electrode 22 have their peripheral edges exposed to the outside, and the electrode exposed surfaces are flat surfaces. As shown in FIG. 2, the electrode exposed surfaces of the first detector 1 and the second detector 2 are
It is installed underground so as to be substantially flush with the road surface 6. Note that the reason why they are installed flush is to make the surface of the road surface 6 and the electrode exposed surface of each detector under the same conditions.

The operation of the road surface condition detection device S having such a configuration will be explained. The outer electrode 11 and the inner electrode 12 of the first detector 1, and the second
A voltage is always applied between the outer electrode 21 and the inner electrode 22 of the second detector 2, and the heater 4 embedded in the interpair insulator 32 of the second detector 2 is also energized to generate heat. I'll let it happen. In this case, four cases arise.

First, when the road surface 6 is dry (that is, when the electrode exposed surface of each detector is dry), the resistance between the inner and outer electrodes of the first and second detectors 1.2 is infinite. becomes close to. (Mode I) On the other hand, when the road surface 6 is wet, the inner and outer electrodes of the first and second detectors 1.2 become electrically conductive due to the presence of water on the exposed surfaces of the electrodes. The resistance between the electrodes is about 10Ω to 200Ω for both electrodes. (Mode II
) In general, if there is snow (or ice) on the road surface 6,
In the second detector 2, the snow on the exposed surface of the electrode is melted by the heat of the heater 4 and becomes water, so the resistance between the outer electrode 21 and the inner electrode 22 is about 10Ω to 200Ω. However, since snow is present on the first detector 1 as well as on the road surface 6, the resistance between the outer electrode 11 and the inner electrode 12 does not decrease as in the second detector 2. This phenomenon is noticeable in the case of so-called "dry snow" with low moisture content (the resistance between the electrodes is close to infinity), and even when "wet snow" or ice is present on the exposed surface of the electrodes, it has a higher electrical potential than water. Since the conduction is quite poor, the resistance is higher than at least the inter-electrode resistance of the second detector 2. (Mode 111) Also, if the road surface 6 is wet but is starting to dry,
In the first detector 1, the electrode exposed surface dries at approximately the same time as the road surface 6, so the inter-electrode resistance is between 10.OMEGA. and 200.OMEGA. until the road surface 6 dries. On the other hand, in the second detector 2, the inter-electrode resistance is It becomes infinite faster than the first detector 1. (Mode ■) The first mode mentioned above.
Table 1 shows the changes in interelectrode resistance depending on the surface condition of the road surface 6 of the detector 1 and the second detector 2.

(Margin below) Table 1 As is clear from Table 1 above, the first and second detectors 1
, 2, and by comparing these measured values, it can be determined whether the surface of the road surface 6 is dry, whether there is snow or ice, or whether there is moisture. I can judge.

That is, the method of the present invention has an advantage in that it can discriminate between the mode I11 and the mode tV.

In reality, in mode III, the inter-electrode resistance of the second detector 2 may not be infinite, but when compared with the inter-electrode resistance of the first detector 1, it is clear that the inter-electrode resistance is Since it is large, there is no risk of misjudgment.

When controlling a road heating device using such a road surface condition detection device S, for example, in the case of mode I, electricity to the heating element is stopped or a preheating operation is performed to maintain the road surface temperature at about -1°C. , Mode II ~ Mode■
In this case, the heating element is energized to maintain the road surface temperature at around +1℃ (freeze prevention operation), and especially in mode 2, the amount of energization is increased to increase the amount of heat generated by the heating element ( Snow melting operation that keeps the road surface temperature around +3℃),
In addition, when shifting from mode II to mode ■, it is possible to gradually reduce the amount of current applied to the heating element, and by combining the extremely effective By adding temperature information to control the road heating system, it is possible to control the road heating system more precisely and efficiently.

Note that in this embodiment, the first. Although the second detector uses a pair of cylindrical electrodes as an example, it is of course possible to use a pair of parallel plate electrodes or the like. In other words, if it has two types of electrode pairs: a so-called snow detection electrode pair for melting snow or ice using heater heat and detecting it as water, and a so-called water detection electrode pair that does not include a heater. good.

[Effect] According to the road surface condition detection method of the present invention as explained above, conventionally it was only possible to determine whether or not there was moisture (water, snow, ice) on the road surface, but with the method of the present invention, it was only possible to determine whether there was moisture (water, snow, ice) on the road surface. Judge whether the top is covered with water, M, or ice. In addition, in the conventional road surface condition detection method using only a sensor with a built-in heater, the surface of the sensor dries faster than the road surface due to the heat of the heater, making accurate moisture detection impossible. In the method of the present invention, such a problem can be solved because a detector consisting of a pair of electrodes without a built-in heater is added.

Therefore, when favsing the road heating device, it is possible to perform more precise control than in the past, and it is possible to drive the device efficiently depending on the road surface condition, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a road surface condition detection device used in the method of the present invention, FIG. 2 is a sectional view showing the device shown in FIG. 1 installed on a road surface, and FIG. FIG. 4 is a plan view showing an example of the state detection device, and FIG. 4 is a sectional view showing the device shown in FIG. 3 installed on a road surface. DESCRIPTION OF SYMBOLS 1...First detector, 2...Second detector, 11°21...-Outer electrode, 12.22...Inner electrode, 31
゜32... Pair insulator, 4... Heater, 5...
Lead wire, 6...Road surface Figure 3 Figure 4

Claims (1)

[Claims] A first detector including a pair of electrodes and an insulator between the pairs, which are partially exposed on the ground surface and arranged substantially flush with the ground surface, and a pair of electrodes and an insulator between the pairs. and a second detector having means for heating the interpair insulator on the road surface, respectively measuring the interelectrode resistance of the first and second detectors, and comparing these measured resistance values. A road surface condition detection method characterized by knowing the road surface condition.