JPS62887A - Detecting device for state of road surface - Google Patents

Abstract

PURPOSE:To identify changes in color of a road surface and to detect only the unevenness of the road surface accurately by detecting the unevenness when the photodetection position of reflected light changes continuously. CONSTITUTION:Signal light emitted by a light emitting element 12 is converged by an irradiation lens 14 so as to illuminate the road surface, and reflected ligt from the road surface is converged by a photodetection lens 16. Further, an optical filter 18 receives only signal light through the lens 16 and removes sunshine, etc. A PSD (semiconductor position detector) 20 photodetects signal light incident through the filter 18 and outputs a photodetection signal corresponding to the photodetection position. Then, when the vehicle runs on an uneven road surface, the photodetection position of the PSD 20 varies continuously upward. On the other hand, when the vehicle runs on a road surface having a white line mark, etc., the photodetection position of the PSD 20 varies upward, but photodetection characteristics are discontinuous. Therefore, a control circuit 30 performs detection only when the photodetection position varies continuously as the vehicle runs, thereby detecting only the unevenness distinctively from a change in the color of the display marks on the road surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a road surface condition detection device that detects unevenness on a road surface, and more specifically, to an optical road surface detection device that can detect unevenness on a road surface while distinguishing it from a change in the color of the road surface. The present invention relates to a state detection device.

[Prior Art] Conventionally, a vehicle suspension tllJm device has been devised that automatically changes the spring constant of the suspension according to the uneven state of the road surface to improve the running performance of the vehicle. This is done by reducing the spring constant on uneven roads to absorb the effects of the road surface, and conversely increasing the spring constant on flat roads to improve driving stability around corners. However, in order to control this type of device, a road surface condition detection device that can accurately detect the road surface condition, that is, the unevenness of the road surface is required.

[Problem that the invention seeks to solve]

However, conventional road surface condition detection devices, for example,
- As described in Publication No. 17182, a vehicle is equipped with a light projector that illuminates the road surface and a light receiver that receives reflected light from the road surface, and the unevenness of the road surface is determined depending on whether the received light signal level from the light receiver is large or not. Since the system is configured to detect irregularities in the road surface, there is a problem in that not only irregularities in the road surface but also changes in the color of the road surface are detected as irregularities in the road surface. In other words, on the road surface, there are signs drawn in white or yellow, such as speed limits and crosswalks, but if you shine light on these types of signs and receive the reflected light, it will be different from the normal road surface. Due to the difference in reflectance, the level of the light signal received by the light receiver increases, and it is detected as unevenness on the road surface.

Therefore, the present invention has been made with the purpose of providing a road surface condition detection device that can distinguish between road surface irregularities and color changes, and accurately detect only road surface irregularities, and has the following configuration. Ta.

Means for Solving Problem E] That is, the configuration of the present invention as a means for solving the above problem, as shown in FIG. a light receiving means M2 that receives reflected light reflected from the road surface by the irradiation of the light emitting means M1 and outputs a light reception signal; and a road surface that detects unevenness of the road surface based on the light reception signal output from the light reception means M2. A road surface condition detection device comprising: a condition detection means M3; a planar light receiving section M5 that receives a beam of reflected light and outputs a light reception signal according to the light receiving position; When the light receiving position changes continuously as the vehicle advances,
The gist of the present invention is a road surface condition detection device characterized by being configured to detect irregularities on a road surface.

Here, the light receiving section M5 may be a conventional image pickup tube or a solid-state image sensor as long as it can receive the beam-shaped reflected light focused by the condensing lens M4 and output a light reception signal according to its position. However, it is possible to use a semiconductor device detector that can continuously measure the light receiving position and has a simple peripheral circuit.
It is desirable to use a so-called PSD (position sensitive detector). Further, 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 be easily distinguished from external light, laser light or the like modulated at a predetermined period may be used. is desirable.

[Function] The road surface condition detection device of the present invention configured as described above detects unevenness of the road surface only when the receiving position of the reflected light in the light receiving portion M5 changes continuously as the vehicle travels. Become.

For example, as shown in FIGS. 2(a), 2(b), and 2(c), when the vehicle travels on an uneven road surface, the light receiving position of the light receiving portion M5 changes continuously from below to above. The light receiving position characteristics as shown in Fig. 3 are obtained, and conversely, Fig. 4 (A) (
b) As shown in (c), when the vehicle runs on a road surface with white line markings such as a crosswalk, the light receiving position of the light receiving part M5 changes from below to above, but the light receiving position characteristics are As shown in Figure 5, the light is discontinuous, so if the unevenness of the road surface is detected only when the light receiving position changes continuously as the vehicle travels, the color change due to the objects displayed on the road surface can be avoided. This is because only irregularities on the road surface can be accurately detected, distinguishing them from changes.

[Example〕 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 detection device of this embodiment.

In the figure, 10 is installed in front of the vehicle and emits signal light.
It represents a light emitting/receiving unit that receives light, and includes a light emitting element 12 that emits a predetermined signal light, and an irradiation lens 14 that focuses the signal light emitted by the light emitting element 12 in order to irradiate the signal light onto the road surface in front of the vehicle. and a light-receiving lens 16 that collects reflected light from the road surface, and of the light that enters through the light-receiving lens 16, only the signal light emitted by the light-emitting element 12 enters, and the signal light emitted by the light-emitting element 12 is inputted to the outside of the sunlight, etc. Optical filter 1 for removing light
8, and a PS that receives the signal light incident through the optical filter 18 and outputs a light reception signal corresponding to the light reception position.
D20.

Next, 22 represents a vehicle speed sensor for detecting the traveling speed (vehicle speed) of the vehicle, and 24 represents 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. Note that the above Psi) 20 is the receiving position of the reflected light.
Since it is only necessary to detect the vertical direction of the surface of the D20, a so-called one-dimensional PSD is used for this PSD20.

The control circuit 30 includes a drive circuit 34 that drives the light emitting element 12 according to a pulse signal output from an oscillation circuit 32, and an amplifier circuit 36 that amplifies detection signals from electrodes provided at both upper and lower ends of the PSD 20. and 38, a multiplexer 40 that selects and inputs the detection signals v1 and v2 representing the light receiving position of the PSD 20 amplified by the amplifier circuits 36 and 38, and the detection signal @ input by the multiplexer 40.
A/D converter 4 that converts v1 or v2 into a digital signal
2, these multiplexers 40 and A/D converters 42
Detection signals v1 and v2 inputted via the oscillation circuit 32, pulse signals oscillated from the oscillation circuit 32, or a vehicle speed signal V representing the vehicle speed detected by the vehicle speed sensor 22 are received to detect irregularities on the road surface in front of the vehicle. It is composed of a microcomputer 44 mainly composed of a CPU that executes road surface condition detection processing, and when an unevenness of the road surface is detected, it drives the actuator 24 to change the spring constant and damping force of the suspension. ing.

The road surface condition detection process executed by the microcomputer 44 will be described in detail below with reference to the flowchart shown in FIG.

As shown in the figure, when the process starts, it first goes to step 100.
, and executes an initialization process to clear flags F1, F2, and the mileage value, which will be described later. When the initialization process is completed, in the following step 101, the oscillation circuit 32
Based on the signal from the light emitting element 12, it is determined whether or not the light emitting element 12 emits light. This process is repeated until the light emitting element 12 emits light, and once the light emitting element 12 emits light, the process moves to the next step 102.

In step 102, the detection signals v1 and v2 corresponding to the receiving position of the reflected light detected by the PSD 20 and amplified by the amplification circuits 36 and 38 and the vehicle speed signal V output from the vehicle speed sensor 22 are input, respectively. Then, the process moves to step 103, and based on the input detection signals @v1 and v2,
The receiving position of the reflected light in SD20, that is, PSD20
The amount of shift X of the light receiving point with respect to the center of is calculated using the following equation, and the process moves to the subsequent step 104.

In step 104, the detected light receiving position is set to PSD2.
It is determined whether the value of X exceeds the value of S, that is, whether the value of X obtained above exceeds the value of S. If it is determined in step 104 that x>S, the process moves to the next step 105, where a flag F1 is set to indicate that there is an object such as a white line or unevenness on the road surface.

If it is determined in step 104 that X≦S, or if flag F1 is set in step 105, the process moves to step 106, where it is determined whether or not flag F1 is set. to decide. If it is determined in step 106 that the flag F1 is in the reset state, the process returns to step 101 and the above process is repeated. .

On the other hand, if there are irregularities or white lines on the road surface, step 1 above
Assuming that the flag F1 is set in step 05, it is determined as rYEsJ in step 106, and the process proceeds to step 107. Next, whether or not the value of X representing the light receiving position obtained in step 103 is smaller than ΔS is determined by 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 it is exactly at the center position of the PSD 20. Determine whether or not.

Here, if it is assumed that the current value has just become X'8 and X≧ΔS, it is determined that rNOJ is established in this step 107, and the process proceeds to the following step 108, in which it is determined whether or not the flag F2 is set. . At this point, flag F2 has not yet been set after being reset in step 100, so in step 108, rN
It is determined that it is OJ, and the process moves to step 101.

Next, after it is determined that there are irregularities or white lines on the road surface,
When the vehicle approaches the unevenness or the white line and reaches x∆S, it is determined that rYEsJ is reached for the first time in step 107, and the next step 109 is executed. In step 109, the vehicle speed signal v1 inputted in step 102, that is, the traveling speed of the vehicle, and the light emitting element 12 generated by the oscillation circuit 32 are used.
The driving period T is used to calculate the distance traveled by the vehicle after the light receiving position is located near the center of the PSD 20. Thereafter, the process moves to step 110, flag F2 is set, and the process moves to step 101 again.

Next, when the vehicle becomes ×2ΔS again as the vehicle travels, step 1
07 is determined as "NO", and step 10B is executed. In step 108, since flag F2 was set in step 110 previously, it is determined that rYEsJ,
The process of step 111 will be executed.

In step 111, it is determined whether the vehicle travel distance L1 determined in step 109 during the previous process, that is, the travel distance traveled by the vehicle while the light receiving position of PS020 is near the center, is smaller than a predetermined value LS. to judge. If it is determined in step 111 that L<LS, it is detected in the next step 112 that the road surface is uneven, and the processing of this routine is terminated.On the contrary, if it is determined that L≧LS, this routine continues. Terminates the process.

By executing the road surface condition detection process as described above, even if there is a display object such as a white line on the road surface and the reflected light from the display object becomes strong, this display object and the unevenness of the road surface can be detected. It becomes possible to accurately identify and detect only irregularities. This is because, as mentioned in the section above, when there are irregularities on the road surface, the light receiving position on the PSD 20 changes continuously, and as shown in Figure 3, the light receiving position moves near the center of the PSD. When the distance traveled during a certain period becomes shorter and, conversely, there is a display object such as a white line, the light receiving position on the PS020 changes discontinuously, and the position moves to near the center of the PSD20 as shown in Fig. 5. This is because the distance traveled over a period of time becomes longer.

[Effects of the Invention] As detailed above, in the road surface condition detection device of the present invention, the beam-shaped reflected light incident through the condensing lens is received by the planar light receiving section, and the light receiving position is determined. The sensor is configured to detect irregularities in the road surface when the angle continuously changes. Therefore, according to the road surface condition detection device of the present invention, unevenness of the road surface will not be erroneously detected due to signs such as crosswalks or speed limits drawn in white or yellow on the road surface, and only the unevenness of the road surface will be accurately detected. be able to be detected. Therefore, by using this device, it becomes possible to perform suspension control and the like with good accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of the present invention, FIGS. 2 to 5 are explanatory diagrams showing the operation of the present invention, and FIG. 2 shows reflected light and its light receiving position when a vehicle runs on an uneven road surface. Fig. 3 is a graph showing the light receiving position characteristics obtained at that time. Fig. 4 is an explanatory drawing showing changes in reflected light and its light receiving position when driving on a road surface with display objects such as white lines. ,
Fig. 5 is a graph showing the light receiving position characteristics at that time, Figs. 6 and 7 show an embodiment of the present invention, Fig. 6 is a block diagram showing the overall structure of the embodiment, and Fig. 7 is a road surface condition. It is a flow chart showing detection processing. 10...Light emitting/receiving unit 12...Light emitting element 14...Irradiation lens 16...Light receiving lens 20...PSD 30...Control circuit

Claims (1)

[Scope of Claims] A light-emitting means for illuminating a road surface in front of the vehicle in the direction of travel; a light-receiving means for receiving reflected light reflected from the road surface by the illumination of the light-emitting means and outputting a light reception signal; and the light-receiving means. A road surface condition detection device comprising a road surface condition detection means for detecting unevenness of the tread surface based on a light reception signal output from the road surface, wherein the light reception means is configured to be a condenser for condensing light reflected from the road surface into a beam shape. The road surface condition detection means is composed of an optical lens, and a planar light receiving section that receives the beam-shaped reflected light focused by the condensing lens and outputs a light reception signal according to the light reception position, and the road surface condition detection means A tread condition detection device, characterized in that it is configured to detect irregularities on the road surface when the light receiving position of the reflected light in the light receiving section changes continuously as the vehicle advances.