JPH0672927B2 - Road condition detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a road surface state detecting device for detecting unevenness of a road surface, and more specifically, an optical road surface capable of detecting the unevenness of the road surface separately from a change in color of the road surface. The present invention relates to a state detection device.

[Prior Art] Conventionally, a suspension control device for a vehicle has been considered, which automatically changes the spring constant of the suspension according to the unevenness of the road surface to improve the drivability of the vehicle. This is to reduce the spring constant on uneven road surfaces to absorb vibration due to the road surface, and conversely increase the spring constant on flat road surfaces to improve running stability at the corners. In this kind of device, the road surface condition,
That is, a road surface state detection device that can accurately detect the unevenness of the road surface is required.

[Problems to be Solved by the Invention] However, a conventional road surface state detecting device is disclosed in, for example, Japanese Patent Laid-Open No. 59-
As described in Japanese Patent No. 17182, a vehicle is equipped with a light projector that illuminates a road surface and a light receiver that receives reflected light from the road surface,
Since it is configured to detect the uneven state of the road surface depending on whether the received light signal level from the light receiver is large,
There is a problem that not only the unevenness of the road surface but also the change of the color of the road surface is detected as the unevenness of the road surface. That is, on the road surface, there are display objects drawn in white or yellow such as speed limits and pedestrian crossings, but when this kind of display object is irradiated with light and the reflected light is received, it becomes a normal road surface. Due to the difference in reflectance, the light reception signal level at the light receiver increases, and it is detected as unevenness on the road surface.

Therefore, the present invention has been made for the purpose of providing a road surface state detecting device capable of discriminating between road surface unevenness and color change and accurately detecting only road surface unevenness, and has the following configuration. It was

[Means for Solving the Problems] That is, as shown in FIG. 1, the structure of the present invention as a means for solving the above problems includes a light emitting means M1 for illuminating the road surface in the vehicle traveling direction, and the light emitting means M1. The light receiving means M2 that receives the reflected light reflected from the road surface by the irradiation of the means M1 and outputs a light receiving signal, and the road surface state that detects the unevenness of the road surface based on the light receiving signal output from the light receiving means M2. In the road surface state detecting device including a detecting means M3, the light receiving means M2 receives a condensing lens M4 that condenses reflected light from the road surface, and receives reflected light condensed by the condensing lens M4. And outputs a light receiving signal according to the light receiving position.
M5 and, further, the road surface state detecting means M3, in the period during which the vehicle travels a predetermined distance as the vehicle advances,
A road surface condition detecting device is characterized in that it is configured to detect unevenness of a road surface when a light receiving position of reflected light at the light receiving section M5 crosses a preset reference section.

Here, as the light receiving unit M5, it is sufficient if it can receive the reflected light condensed by the condenser lens M4 and output a light reception signal corresponding to the position thereof, and a conventional image pickup tube or a solid-state image pickup element can also be used. However, continuous light receiving position measurement is possible,
It is desirable to use a semiconductor position detector with a simple peripheral circuit, a so-called PSD (Position Sensitive Detector). The light emitted from the light emitting means M1 may be any light as long as it can be received by the light receiving section 5, but in order to make it easy to distinguish it from external light, laser light or the like modulated at a predetermined cycle is used. Is desirable.

[Operation] In the road surface state detecting device of the present invention configured as described above, the light receiving position of the reflected light at the light receiving unit M5 is preset within a period in which the vehicle moves a predetermined distance as the vehicle advances. Roughness of the road surface is detected when it crosses the specified reference section.

The reason for this will be described below.

First, as shown in FIGS. 2 (a), (b), and (c), when the vehicle travels on a road surface having a convex portion, the relative distance between the light receiving portion M5 and the convex portion as the vehicle travels is increased. Due to the position change, the light receiving position at the light receiving unit M5 changes from the lower side to the upper side (see P1 in FIG. 2).
Since it changes continuously (from P3 to P3),
As shown in FIG. 3, a light receiving position characteristic that changes substantially linearly is obtained.

On the other hand, as shown in FIGS. 4 (a), (b), and (c), when the vehicle travels on a road surface with a white line display such as a pedestrian crossing, as in the case where there is a convex portion on the road surface, Due to the relative position change between the light receiving unit M5 and the white line as the light progresses, the light receiving position at the light receiving unit M5 changes from the lower side to the upper side (from P4 to P6 in FIG. 4).
Change). However, in this case, the white line has a width along the traveling direction of the vehicle, so that the white line in FIG.
As shown in, the white line is entirely irradiated with the light from the light emitting means M1 according to the width of the white line, and only the reflected light from the white line is incident on the light receiving unit M5. During this period, the light receiving position in the light receiving unit M5 is
It will be the approximate center position of the light receiving part corresponding to the focus of M4. Therefore, during this period, the light receiving position characteristic obtained by the light receiving portion M5 becomes constant as indicated by L in FIG. 5, and the light receiving position characteristic which changes substantially linearly is obtained like the road surface having the convex portion. Absent.

Therefore, in the present invention, as the vehicle advances, the light receiving position of the reflected light at the light receiving unit M5 is set in a predetermined reference section (see FIG. 3,
The period when crossing the central position in FIG. 5 (FIG. 3,
It is determined whether or not L) in FIG. 5 is within a period in which the vehicle moves for a predetermined distance, and the unevenness of the road surface is detected only when this period L is within a period in which the vehicle moves for a predetermined distance. I am doing it.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 is a block diagram showing the overall configuration of the road surface condition detecting device of this embodiment.

In the figure, reference numeral 10 denotes a light emitting / receiving unit which is provided in front of the vehicle and which emits / receives signal light. The light emitting element 12 that emits a predetermined signal light and the signal light emitted by the light emitting element 12 are provided in front of the vehicle. An irradiation lens 14 that collects the signal light to irradiate the road surface, a light receiving lens 16 that collects the reflected light from the road surface, and a light emitted from the light emitting element 12 among the light incident through the light receiving lens 16. An optical filter 18 for receiving only the signal light that has been received and removing other external light such as sunlight.
It is composed of a PSD 20 which receives the signal light incident via 18 and outputs a light reception signal corresponding to the light reception position. Next, 22 is a vehicle speed sensor for detecting the traveling speed (vehicle speed) of the vehicle, and 24 is an actuator for changing the spring constant and damping force of the suspension of the vehicle, which is connected to the control circuit 30 together with the light emitting / receiving unit 10. ing.
Here, the PSD20 has a PN junction with a uniform resistance layer on the surface of a high resistance semiconductor, and a pair of electrodes for signal extraction is provided at both ends of the resistance layer to cope with photocurrent generated in each electrode by photoelectric effect. It is a well-known signal that generates the detected signals V1 and V2, and in the present embodiment, since it is sufficient to detect only the vertical direction of the PSD20 surface as the light receiving position of the reflected light, this PS
So-called one-dimensional PSD is used for D20.

The control circuit 30 includes a drive circuit 34 that drives the light emitting element 12 according to a pulse signal output from the oscillator circuit 32, and a PSD 20.
Amplifying circuits 36 and 38 for amplifying the detection signals from the electrodes provided at the upper and lower ends, and the detection signals v1 and v2 representing the light receiving position of the PSD 20 amplified by these amplifying circuits 36 and 38 are selected and input. And a multiplexer 40 for converting the detection signal v1 or v2 input by the multiplexer 40 into a digital signal
A / D converter 42, multiplexer 40 and A / D converter
The detection signals v1 and v2 input via 42 and the above oscillation circuit
A pulse signal oscillated from 32 or a vehicle speed signal V representing the vehicle speed detected by the vehicle speed sensor 22 is received, and road surface state detection processing for detecting irregularities on the road surface in front of the vehicle is executed.
It is composed of a microcomputer 44 composed mainly of a CPU, and an actuator when detecting the unevenness of the road surface.
It drives 24 to change the spring constant and damping force of the suspension.

Hereinafter, the road surface state detection processing executed by the microcomputer 44 will be described in detail with reference to the flowchart shown in FIG.

As shown in the figure, when the process is started, step 100 is first executed, and an initialization process is executed to clear the values of flags F1 and F2 and the traveling distance L which will be described later. When the initialization process is completed, it is determined in the following step 101 whether or not the light emitting element 12 emits light based on the signal from the oscillation circuit 32. This process is repeated until the light emitting element 12 emits light, and when the light emitting element 12 emits light, the next step 102
Move to.

In step 102, the detection signals v1 and v2 detected by the PSD 20 and amplified by the amplifier circuits 36 and 38 according to the light receiving position of the reflected light are detected.
The vehicle speed signal V output from the vehicle speed sensor 22 is input. Then, the process shifts to step 103, and based on the input detection signals v1 and v2, the light receiving position of the reflected light on the PSD20, that is, the shift amount X of the light receiving point with respect to the center of the PSD20 is calculated by the following equation. After that, the process proceeds to the subsequent step 104. That is, P
The detection signals V1 and V2 output from the SD20 are proportional to the amount of displacement of each light receiving point from each electrode, and the sum (V1
+ V2) corresponds to the vertical length of PSD20, and the difference (V1
-V2) corresponds to the deviation of the light receiving point from the center of the PSD20. Therefore, in the present embodiment, the deviation of the light receiving point from the center of the PSD20 is calculated by calculating the ratio of the sum and the difference using the above-mentioned arithmetic expression. Is obtained and is set as the deviation amount X of the light receiving point with respect to the center of the PSD 20.

In step 104, it is determined whether or not the detected light receiving position deviates from the center of the PSD 20 by a predetermined amount S, that is, whether or not the obtained value of X exceeds the value of S. When it is judged in this step 104 that X> S, the routine proceeds to the next step 105, and a flag F1 indicating that there is a display object such as a white line or unevenness on the road surface is set.

If it is determined in step 104 that X ≦ S,
Alternatively, when the flag F1 is set in the above step 105, the process proceeds to the following step 106 and it is determined whether or not the flag F1 is set. And this step
When it is determined in 106 that the flag F1 is in the reset state, the process returns to step 101 and the above-described processing is repeated.

On the other hand, there are irregularities or white lines on the road surface,
If it is assumed that the flag F1 has been set in step 5, it is determined to be "YES" in step 106, and the process proceeds to step 107. Then, this time, whether or not the value of X representing the light receiving position obtained in step 103 is smaller than ΔS, that is,
It is determined whether or not the deviation amount X of the light receiving position with respect to the center of the PSD 20 is sufficiently small and is approximately at the center position of the PSD 20.

Here, it is immediately after X> S, and if X ≧ ΔS, it is determined to be “NO” in this step 107, the process proceeds to the following step 108, and it is determined whether or not the flag F2 is set. to decide. At this point, the flag F2 has not been set yet after being reset in step 100, and therefore in this step 108 it is determined to be "NO" and the routine proceeds to step 101.

Next, after it is determined that there are unevenness or white lines on the road surface,
When the vehicle approaches the unevenness, the white line, or the like, and X <ΔS, it is first determined to be “YES” in step 107, and the next step 109 is executed. In step 109, the light receiving position is located near the center of the PSD 20 by using the vehicle speed signal V input in step 102, that is, the vehicle traveling speed V and the driving cycle T of the light emitting element 12 by the oscillation circuit 32. After that, the traveling distance L of the vehicle is calculated. After that, the processing shifts to Step 110, the flag F2 is set, and the processing shifts to Step 101 again.

Next, when X ≧ ΔS again as the vehicle travels, step 10
It is determined to be "NO" at 7, and step 108 is executed. In step 108, since the flag F2 was set in step 110 last time, it is determined to be "YES", and the process of step 111 is executed.

In step 111, it is determined whether or not the traveling distance L of the vehicle obtained in step 109 in the previous processing, that is, the traveling distance L of the vehicle while the light receiving position of the PSD 20 is near its center is smaller than a predetermined value Ls. To judge. And step 111
When it is determined that L <Ls in step 112, it is detected that the road surface is uneven in the next step 112, the processing of this routine is ended, and conversely, when it is determined in step 111 that L ≧ Ls, it is as it is. The processing of this routine ends.

As described above, in the present embodiment, the light receiving position of the reflected light on the PSD 20 is set to the reference section (the area indicated by the alternate long and short dash line in FIGS. 3 and 5) near the center position of the PSD 20 determined by the value ΔS. When crossing, the period L in which the light receiving position exists within the reference section is calculated from the traveling distance of the vehicle, and the value L
Is smaller than the predetermined value Ls, in other words, when the light receiving position crosses the reference section within a period in which the vehicle moves for a predetermined distance, the unevenness of the road surface is detected.

Therefore, according to the present embodiment, the light receiving position characteristic shown in FIG. 3 which changes due to the unevenness of the road surface as the vehicle advances and the light receiving position characteristic shown in FIG. 5 which changes according to the display object on the road surface as the vehicle advances. Even if there is a white line or other display object on the road surface and the reflected light reflected from the display object becomes strong, such a display object will be mistaken as unevenness on the road surface. Only the unevenness of the road surface can be accurately detected without detection.

In the present embodiment, when the light receiving position of the reflected light on the PSD 20 is largely deviated from the center position of the PSD 20 by a predetermined amount or more determined by the value S (from the area indicated by the chain double-dashed line in FIGS. 3 and 5). Step 107 to Step 1
I tried to judge the unevenness of the road surface by 12, but this is
This is to prevent erroneous determination of the unevenness of the road surface when the light receiving position crosses the reference section due to vibration or the like received from the vehicle body by the PSD 20, and if there is no such problem, it is not necessary to set such determination conditions.

Further, in the present embodiment, the light receiving position of the PSD20 detects the traveling distance of the vehicle as a period existing in the reference section, and detects the unevenness of the road surface when the detected distance is smaller than a predetermined value. Since the unevenness of the road surface can be detected when the light receiving position of the PSD 20 crosses the reference section within a period in which the vehicle moves for a predetermined distance, it is not always necessary to directly detect the traveling distance of the vehicle as in the present embodiment. Not, for example PS
You may make it measure the time when the light receiving position in D20 existed in the said reference area, and when the time is smaller than the predetermined time set according to the vehicle speed, the unevenness of the road surface may be detected.

That is, as is well known, the traveling distance of the vehicle is the vehicle speed multiplied by the traveling time, and if the vehicle speed can be known,
Since it can be measured by time, set the time required for the vehicle to move a predetermined distance from the vehicle speed,
Even if the unevenness of the road surface is detected when the time required for the light receiving position on the PSD20 to cross the reference section is measured and the measured time is shorter than the set time set according to the vehicle speed, The invention can be realized.

[Advantages of the Invention] As described in detail above, in the road surface state detecting device of the present invention, the light receiving section receives the reflected light condensed by the condensing lens, and the light receiving position thereof is a preset reference section. When the vehicle crosses within the period of traveling a predetermined distance,
It is designed to detect irregularities on the road surface.

Therefore, according to the road surface state detection device of the present invention, there is no erroneous detection of an object such as a pedestrian crossing or a speed limit drawn in white or yellow on the road surface as road surface unevenness, and only the road surface unevenness is accurately detected. Will be able to detect.

Therefore, by using this device, suspension control and the like can be executed accurately and favorably.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIGS. 2 to 5 are explanatory diagrams showing the operation of the present invention. FIG. 2 is a reflected light and its light receiving position when the vehicle is running on an uneven road surface. FIG. 3 is a graph showing the light receiving position characteristic obtained at that time, FIG. 4 is an explanatory view showing the reflected light and the change of the light receiving position thereof when the road surface running with an object such as a white line is traveling, and FIG. FIG. 6 is a graph showing the light receiving position characteristic at that time, FIGS. 6 and 7 show an embodiment of the present invention, FIG. 6 is a block diagram showing the overall configuration of the embodiment, and FIG. 7 is a road surface state detection process. 2 is a flowchart showing 10 …… Light emitting / receiving unit 12 …… Light emitting element 14 …… Irradiation lens 16 …… Light receiving lens 20 …… PSD 30 …… Control circuit 44 …… Microcomputer

Front page continued (72) Inventor Yoshihide Kamisato 1-2-2 Gosho-dori, Hyogo-ku, Kobe-shi, Hyogo Fujitsu Ten Limited (72) Inventor Hiroshi Kobayashi 1-2-gosho-dori, Hyogo-ku, Hyogo Prefecture No. 28 in Fujitsu Ten Limited

Claims (1)

[Claims] 1. A light emitting means for irradiating a road surface ahead of a vehicle traveling direction, a light receiving means for receiving a reflected light reflected from the road surface by the irradiation of the light emitting means and outputting a light receiving signal, and the light receiving means. A road surface condition detecting means for detecting irregularities of the road surface based on an output light receiving signal; and a road surface condition detecting device comprising: a light receiving means, a condenser lens for collecting reflected light from the road surface, A planar light-receiving unit that receives the reflected light condensed by the condensing lens and outputs a light-reception signal corresponding to the light-receiving position of the reflected light; With the progress of, within the period when the vehicle moves a predetermined distance,
A road surface state detecting device configured to detect unevenness of a road surface when a light receiving position of reflected light at the light receiving unit crosses a preset reference section.