JPS5840710B2 - Road condition detection device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a road surface condition detection device.

Modulated light (lOOH2 or 120H2) is projected onto the road surface from a projector, and the amount of reflected light is calculated as the amount of reflected light relative to the surface surface WA, and the amount of diffused reflection (the amount of diffused reflection from markings or the equivalent reflectance SA, and the amount of diffused reflection from the normal road surface) WSB. By concentrating light with two concentrators and electrically processing the relative change, moisture and snow on the road surface can be detected without contact.

FIG. 1 shows a detection device of this type.

In Fig. 1, 101 is a road, 102 is a support, 103
104 is an arm provided on the top of the support 102, 104 is a floodlight provided on the support 102, 105 is a marking provided on the road 101, and 106 is a collector for detecting surface light emitted from the floodlight 104 and projected in white on the road surface. The light receiving level of this condenser 106 is WA.

Reference numeral 107 is a condenser that detects diffused reflection from the road surface, and the 9Je bell of this condenser 107 is WSB.

10B is a condenser that detects the diffusely reflected light reflected by the marking 105, and the light reception level of this condenser 108 is S.
It is A.

The condensers 106, 107 and 108 are composed of a lens system and a photoelectric conversion element, and the condenser 106 is installed with its optical axis facing the road surface other than the markings, so that it collects light emitted from a limited portion of the road surface. The condenser 107 is installed with its optical axis directed toward the road surface other than the markings, and receives diffusely reflected light from a limited portion of the road surface.

On the other hand, the condenser 108 is installed with its optical axis facing the marking, and receives diffusely reflected light from the marking portion.

109 is a road surface hygrometer such as an infrared radiation thermometer.

Figure 2 shows the relationship between the light reception levels of each condenser under dry road conditions, wet road conditions, and snowfall conditions. When the road surface is wet, WA and WSB occur as shown in the table below, and the water detection signal is becomes 6".

Also, if there is snow, WSB-SA will be activated and the snow detection signal will be activated.
“Yes”.

When the road surface temperature measured by the road surface thermometer 109 is combined with the water detection and snow detection described above, the road surface condition can be determined into four states: dry, wet, snowy, and frozen, as shown in Table 1.

However, in the above judgment logic that attempts to detect freezing under two conditions: moisture present and road surface temperature below 0°C, in the following cases,
The detected content may not match the actual road surface phenomenon.

l When spraying antifreeze, due to the freezing point phenomenon,
Even if the road temperature drops below O'C, the road surface often does not freeze.

In such a case, due to the detection conditions described above, a humid state where the road temperature is 0° C. or less will be detected as freezing.

2. Due to the error of the thermometer, it is possible that the thermometer indicates 0°C, but the actual temperature is +0.5°C and the road surface is wet.

In such a case, it will naturally be erroneously detected as frozen.

However, in the natural world, road temperatures often change rapidly, so freezing is detected a little earlier than actual freezing (10
30 minutes), which is a rather desirable detection output.

The present invention aims to solve these problems, and will be explained below.

First, the modulated light from a light projector installed at the detection location is applied to the detection road surface and is accurately captured by separate condensers as the surface skin ratio WA and the diffuse reflection amount WSB, and if the ratio exceeds a predetermined constant, In the state of A WSB"K, a signal indicating the presence of moisture is issued, and according to the judgment logic, there is moisture and freezing is detected when the road temperature is below 0°C.

By the way, in the case of a road, when the road is wet, the surface skin to vehicle ratio becomes much larger than when it is frozen.

By utilizing this property, it is possible to detect when the road is below 0°C and not frozen.

On the other hand, even if there is snow, it will be difficult to judge whether the anti-reflection ratio has increased because the white text will be "b!"
Since detection will be incorrect in the case of snow, it should be determined that it is wet only when snow is not detected.

For this reason, we will add a comparison to the decision logic in Table 1 shown above and create the decision logic in Table 2.

That is, in the present invention, even if it is detected that there is moisture and the temperature is below 0° C., freezing detection is prohibited when the condition of formula (g) is satisfied, and a logic is added to detect moisture.

FIG. 3 shows an example of this, in which 1L21.31 is an AC amplifier in which the plow level is also set to the setting values of setters 12, 22, and 32, 13.23.33 is a bandpass amplifier, 14. 24 and 34 are rectifier amplifiers, 1 to 3 are comparators, and 4 is an @flow amplifier that sets the level based on the setting value of the setting device 5. Water detection output is output from terminal 6, and snow detection output is output from 7. , 5vc so that freeze prohibition output can be obtained from 8.

41.51 is the setting value STV>T1 of the setting devices 42, 52,
ST■〉T2, 0.5℃ for T, Otsuji temperature comparison circuit that compares T2--2℃ and Ro-on human power STV, 43.53.61~
63 is an inverter, 64 is a gate that obtains a dry (DRY) output from the AND of the outputs of inverters 61 and 62, 65 is a gate that ANDs the output of inverters 43 and 63 and the output that is applied to terminal 6, and 66 is a gate that is connected to terminal I. AND the applied output and the output of the inverters 53 and 63, and the O gate, 67
is a gate that obtains the freeze (ICE) output from the OR of gates 65 and 66, 68 is a gate that ANDs the output of the comparison circuit 51 and the output applied to terminal 8, and 69 is the output of the comparison circuit 51, the output of the inverter 62, and the terminal. 70 is a gate that ANDs the output of the comparator circuit 41 and the output of the inverter 43 to obtain the SNOW output; 70 is a gate that ANDs the output of the comparison circuit 41 and the stone output that is applied to terminal 6; 71 is the gate 70
This is a gate that takes an OR between the output of the gate 68 and the output of the gate 68 to obtain a wet output.

With this configuration, since the output of the gate 68 is applied to the gates 65 and 66 through the inverter 63, an erroneous freezing output is not output from the gate 67.

On the other hand, the output of gate 68 is passed through gate 11 to gate 7.
Because it is obtained regardless of the presence or absence of an output of 0, a wet output is obtained, and from this, judgment results as shown in Table 2 are obtained.

Therefore, even if antifreeze is sprayed on the road surface, accurate determination results can be obtained, which is advantageous in practice.

The present invention has the above configuration and has the advantage of being able to accurately determine whether the road surface is frozen or wet.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the detection unit of the road surface condition detection device, Fig. 2 is a diagram showing the relationship between the light reception level of each concentrator of the same detection device and the road surface condition, and Fig. 3 is according to an embodiment of the present invention. FIG. 2 is a block diagram of a road surface condition detection device. 1.2, 3... Comparator, 65, 66...
·Gate.

Claims (1)

[Claims] 1. A light projecting means for projecting light onto the road surface, a first light condensing means for receiving the white light emitted from the road surface and outputting the surface skin output WA, and receiving the diffused reflection output from the marking portion of the road surface and performing the diffused reflection. a second light collecting means for outputting the output SA; a third light collecting means for receiving the diffusely reflected light from the road surface and outputting the diffusely reflected output WSB; a road surface temperature detecting means for detecting the road surface i; The output WA of the first condensing means and the third condensing means
a first comparing means that compares the output WSB of the light collecting means and outputs a water detection output when WA>WSB; an output SA of the second light collecting means and an output of the third light collecting means; WSB
and a second comparison means that outputs a snow detection output when WSB>SA, and determines whether the road surface is dry or wet based on the outputs of the first and second comparison means and the output of the road surface base i detection device. , a determining means for determining snow accumulation or freezing, and comparing the output WA of the first condensing means and the output WSB of the third condensing means, and the ratio of WA and WSB is greater than the ratio in the road surface dry state. a third comparison means that outputs an output when the first comparison means outputs a water detection output, the road surface temperature detection means detects a freezing temperature, and the third comparison means outputs an output; and a gate means for prohibiting the determination means from making a determination as to whether it is frozen or determining whether the determination means is wet based on the output of the third comparison means.