JP3364982B2 - Obstacle detector and radius of curvature detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detecting device for monitoring the front of a vehicle to detect an obstacle such as a preceding vehicle, and a curvature radius detecting device for detecting a radius of curvature of a road on which a vehicle is traveling. .

[0002]

2. Description of the Related Art In recent years, various techniques have been proposed and put to practical use in order to ensure safe and reliable running of automobiles. For example, there has been proposed a technique of avoiding a collision with an obstacle in front of the vehicle or traveling by following a preceding vehicle by detecting an existing object such as another vehicle in front of the vehicle ( JP-A-3-924436 and JP-A-3-11
1785). In these technologies, in general, the measuring light is emitted from the own vehicle over a required measurement angle range, and the presence of the measuring light is detected by detecting the reflected light from the front existing object due to the measuring light. The distance to the front object is measured according to the time from the detection of reflected light. Also, in order to identify the vehicle in front,
JP-A-59-203975 and JP-A-2-1648
Japanese Patent Laid-Open No. 4 and the like disclose a technique of setting a measurement limit value and comparing the detection distance of the obstacle with the measurement limit value to determine whether or not the obstacle is in the own lane.

[0003]

However, the conventional device for detecting an object in front of the vehicle has the following problems because it detects an obstacle within a predetermined angle range in front of the host vehicle. . That is, there is a possibility that an object other than the lane in which the vehicle is traveling, such as a vehicle traveling in an adjacent lane or an oncoming lane, may be detected. Further, while the vehicle is traveling on a curved road, there is a possibility that road installation objects such as reflectors and guardrails installed on the side road may be detected.
Further, in the above-described technique of determining whether or not the obstacle is in the own lane, the obstacle is detected in the conical area in front of the own vehicle, but in the conical measurement area, the adjacent lane from the own vehicle is detected. , The distance to the oncoming lane, and the side road differ depending on the angle with respect to the traveling direction. For this reason, only by setting a certain measurement limit value, it is possible to detect a vehicle traveling in an adjacent lane or an oncoming lane or a road installation installed in a side road in a partial angular range. There is a problem. In the case of a curved road with a small radius of curvature R, sufficient inspection
It may not be possible to secure the knowledge range. Therefore, the first aspect of the present invention
The purpose of changing the maximum scan angle according to the width of the lane
Therefore, even in a curved road with a small radius of curvature R, a sufficient detection range can be obtained.
An object of the present invention is to provide an obstacle detection device capable of ensuring an enclosure . Therefore, a second object of the present invention,
By detecting the effective detection distance with high accuracy,
Obstacle detection that can exclude the object from the detection target
To provide a device.

[0004]

According to a first aspect of the present invention, a lane width setting means for setting the width of the lane in which the vehicle is traveling.
Depending on the step and the lane width set by the lane width setting means
The scanning means for scanning the area within the maximum scanning angle range to detect the direction and distance of the object existing in the area, the angular velocity detecting means for detecting the angular velocity of the own vehicle, and the speed for detecting the velocity of the own vehicle. Detecting means, radius-of-curvature calculating means for calculating the radius of curvature of the lane in which the vehicle is traveling, based on the angular velocity detected by the angular velocity detecting means and the velocity detected by the velocity detecting means, and the radius-of-curvature calculating means. The detection effective distance calculating means for obtaining the detection effective distance for each scanning direction of the scanning means based on the radius of curvature obtained by the scanning means, and the distance of the object detected by the scanning means are the detection effective in the direction of the object. The object is achieved by providing an obstacle detection device with an obstacle determination means for determining whether or not the object is an obstacle when the object is within the distance. In the invention described in claim 2, the obstacle described in claim 1
In the object detection device , the detection effective distance calculation means is
The radius of curvature obtained by the radius calculation means and the lane
Based on the width of the lane set by the width setting means, the scanning hand
The feature is that the detection effective distance is obtained for each scanning direction of the step.
To do. In the invention described in claim 3, claim 1 or claim
2. The obstacle detection device according to 2, wherein the lane width setting hand is
The step indicates the width of the lane in which the vehicle is traveling, the speed detecting means.
Navigation automatically set from the speed detected by
Automatically by obtaining lane width information in the system map information
Set or set according to the lane width input from the panel etc.
It is characterized by doing.

[0005]

In the obstacle detecting device according to claim 1 , the lane width setting
The width of the lane in which the vehicle is traveling is set by the fixing means,
Maximum according to the lane width set by the lane width setting means
The area within the scanning angle range is scanned, and the direction and distance of the object existing in the area are detected by the scanning means, the angular speed of the own vehicle is detected by the angular speed detecting means, and the speed of the own vehicle is detected by the speed detecting means. Then, based on the angular velocity and the velocity, the radius-of-curvature calculation means obtains the radius of curvature of the lane in which the vehicle is traveling. Then, based on the obtained radius of curvature, the detection effective distance calculation means calculates the detection effective distance for each scanning direction, and the obstacle determination means determines the distance of the object detected by the scanning means in the direction of the object. If it is within the detection effective distance, it is determined whether or not the object is an obstacle. Claim 2
In the obstacle detection device of,
The radius of curvature and the lane width set by the lane width setting means.
Based on this, the detection effective distance is obtained for each scanning direction of the scanning means.
Meru. In the obstacle detection device according to claim 3, the own vehicle is
The width of the traveling lane is determined by the speed detected by the speed detection means.
Automatically set from the navigation system map information
The lane width information is obtained and automatically set, or the panel
Set according to the lane width input from, etc.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of an obstacle detecting device and a curvature radius detecting device of the present invention will be described below in detail with reference to FIG. 1 and FIG. FIG. 1 is an explanatory diagram showing a configuration of an obstacle detection device including a curvature radius detection device in this embodiment. This obstacle detection device is installed in the vehicle,
It detects an obstacle such as a preceding vehicle. As shown in FIG. 1, the obstacle detection device includes a light emitting unit and a scanning unit as scanning means. The light emitting unit of the scanning means includes a laser 11 such as a semiconductor laser that emits laser light as scanning light, a light emission drive unit 12 that drives this laser 11, and a condenser lens that condenses the laser light emitted from the laser 11. 1
3. A cylindrical lens 14 is provided which makes the laser light passing through the condenser lens 13 vertically elongated slit light. Further, the light emitting portion of the scanning means reflects the laser light that has passed through the cylindrical lens 14 and becomes slit light, and deflects it to the left and right to scan an area within a predetermined angle range in front of the vehicle. The mirror 15 and the mirror driving unit 16 that rotates the mirror 15 are provided. The mirror 15 may be a polygon mirror or a galvano mirror. Further, instead of the mirror, the deflection may be performed by changing the magnetic field around the optical system. Instead of scanning with slit light, one spot light or a plurality of spot lights arranged in the vertical direction may be formed and the spot light may be used for scanning.

On the other hand, the obstacle detecting device serves as a light receiving portion of the scanning means, and a condenser lens 1 for condensing reflected light from an object.
7. Of the light passing through the condenser lens 17, the laser 11
And a light receiving element 19 such as a photodiode for receiving the light passing through the filter 18, and a light receiving and amplifying section 20 for amplifying the output signal of the light receiving element 19. Is equipped with. Further, the obstacle detection device is provided with a speedometer 21 for detecting the speed of the host vehicle and an angular velocity meter 22 for detecting the angular speed of the host vehicle, as instruments for detecting the radius of curvature of the road on which the vehicle is traveling. There is. As the angular velocity meter 22, a gyro such as a piezoelectric type or an optical fiber type can be used.

The obstacle detecting device has a lane width setting unit 23. The lane width setting unit 23 determines from the vehicle speed detected by the speedometer 21 whether the host vehicle is traveling on an expressway or an ordinary road, and automatically sets a lane width corresponding to each. It is like this. Lane width setting section 2
As for 3, the driver may input the lane width from a panel or the like, or in a vehicle equipped with a navigation system, the lane width information may be automatically set by obtaining the lane width information from the map information. The lane width is defined by the road section, and, for example, a minimum of 2.75 m to a highway of 3.5 m is selected.

The obstacle detection device is also provided with a control unit 30, which has a lane width setting unit 23 for setting the width of the lane in which the vehicle is traveling, a speedometer 21, and an angular velocity meter 22. The lane width setting unit 23, the light emission drive unit 12, the mirror drive unit 16, and the light reception amplification unit 20 are connected. The control unit 30 exists in the scanning area based on the light emission control unit 31 that controls the light emission drive unit 12 and the mirror drive unit 16, and the scanning direction information from the light emission control unit 31 and the signal from the light reception amplification unit 20. The angle (direction) of the object and the angle to obtain the distance
The distance detection unit 32 is provided.

The control unit 30 also includes a curvature radius calculation unit 3.
3, a detection effective distance calculation unit 34, and an obstacle determination unit 35. The radius-of-curvature calculation unit 33 calculates the radius of curvature of the lane in which the vehicle is traveling, based on the speed detected by the speedometer 21 and the angular speed detected by the angular speedometer 22. The detection effective distance calculation unit 34 uses the curvature radius calculation unit 3
The effective detection distance is calculated for each scanning direction based on the radius of curvature calculated in step 3 and the scanning direction information from the light emission control unit 31. The obstacle determination unit 35 includes the angle / distance detection unit 3
The object is determined to be an obstacle only when the distance of the object detected by 2 is within the detection effective distance in the direction of the object. The control unit 30 is composed of, for example, a well-known microcomputer, and realizes the function of each of the above units by executing a program. It should be noted that the velocity meter 21, the angular velocity meter 22, and the radius-of-curvature calculation unit 33 constitute a radius-of-curvature detection device.

Next, the operation of the embodiment thus constructed will be described. Laser light is emitted as pulsed light from the laser 11 by the current supplied from the light emission drive unit 12. This laser light is condensed by the condenser lens 13, is made into a vertically elongated slit light by the cylindrical lens 14, is reflected by the mirror 15 rotated by the mirror driving unit 16, and is emitted to the front of the vehicle. The scanning is performed right and left within a predetermined angle range (2 · θ _max ). Note that the light emission control unit 31 can emit the pulsed light at a certain angle and at a certain time interval by synchronizing the rotation of the mirror 15 and the timing of emitting the pulsed light.

The laser light emitted from the laser 11 is reflected by a reflecting object such as a reflector at the rear of the vehicle in front. The reflected light is condensed by the condenser lens 17, and only the light having the wavelength of the laser light emitted from the laser 11 passes through the filter 18 and is received by the light receiving element 19. The output signal of the light receiving element 19 is amplified by the light receiving amplification section 20 and sent to the angle / distance detection section 32. The angle / distance detection unit 32 detects the angle of the mirror 15 and the time required from when the laser light is emitted forward to when it is reflected by the reflective object and received by the light receiving element 19.
From these, the scanning angle θ _t of the laser light at time _t ,
And the distance l _t to the front reflecting object at that angle
Ask for. Distance l to the reflecting object at the scanning angle θ _{t
When t,} that is, the detection distance is obtained, the obstacle determination unit 35 determines whether or not this object is an object existing in the same lane as the lane in which the vehicle is traveling. Hereinafter, this determination method will be described in detail.

First, a detection effective distance indicating an area within the lane in which the vehicle is traveling is obtained from the scanning area at a predetermined angle. In the present embodiment, the radius of curvature R and the lane width W of the lane in which the vehicle is traveling are used to obtain the effective detection distance. The radius of curvature R is calculated by the radius of curvature calculator 33 based on the velocity v of the host vehicle detected by the speedometer 21 and the angular velocity φ of the host vehicle detected by the angular velocity meter 22.
It is calculated using the following formula. R = v / φ Meanwhile, the lane width W is set by the lane width setting unit 23. Then, based on the radius of curvature R and the lane width W, the detection effective distance calculation unit 34 obtains the detection effective distance.

The method for obtaining the effective detection distance will be described below with reference to FIGS. 2 and 3 separately for a straight road and a curved road. (1) In the case of a straight road FIG. 2 is an explanatory view showing a state during traveling on a straight road. In this figure, RL is the left side line of the road, RR is the right side line of the road, and CL
Is the center line of the road, and CC is the center line of the lane in which the vehicle V travels. In addition, the scanning range of the laser light is symmetric and SL
That is, from the scan angle −θ _max to SR, that is, the scan angle θ
Up to _max . Also, the center line is SC, that is, the scan angle is 0.
And The point A is the center of the front part of the host vehicle, and the laser is emitted forward from this position. As can be seen from FIG. 2, if the detection distance l _t at the scanning angle θ _t is shorter than the distance L _t in the figure, it can be seen that this object is in the own lane. Here, L _t is hereinafter referred to as a detection effective distance or simply an effective distance. That is, if l _t <L _t , the object is in the own lane.

When θ _t ≠ 0, the relationship between the effective distance L _t and the scanning angle θ _{t at} that time is as follows:
From the figure, since L _t · | sin θ _t | = W / 2 holds, the effective distance L _t can be calculated by L _t = W / (2 · | sin θ _t |). However, L obtained from this equation
_The range of possible values of _t is L _t > W / (2 · | sin θ _max |), but the detection capability of the system is a finite value,
The resulting L _t is the L _t> L _max become scan angle theta _t, and L _t = L _max. When θ _t = 0, in this case, L _t = L _max . Here, L _max is set to, for example, about 100 (m) from the viewpoint of the detection capability of the system, the purpose of use of the obstacle detection result (deceleration, etc.), and the like.

(2) In the case of a curved road FIG. 3 is an explanatory view showing a state where the vehicle is traveling on a curved road with a right curve. Here, SS represents the direction of the laser beam in contact with the road center line CL, and the scanning angle at that time, that is, the tangent angle is β. In the case of a left curve, SS contacts RL. In the figure, when the contact point between SS and CL is P, OP = AO · cosβ, and when the radius of curvature is R, AO = R, OP = RW−W / 2. / 2 = R · cos β, and the tangent angle β can be obtained by β = cos ⁻¹ {1-W / 2R} (1) Further, as understood from the figure, the straight line drawn from the point A to the front of the host vehicle intersects only one point with the curve RL in the range from SL to SS.
Therefore, this distance is L _t . But SS to SR
In the range up to, since there are two intersections with the curve CL in the front, the shorter one is defined as L _t . Therefore, the effective distance L _{t in} the case of a curved road can be obtained as follows.

When −θ _max ≦ θ _t <β, the point A is the origin, and the arc RL is represented by an orthogonal coordinate system with the AO axis as the x axis and the AX axis as the y axis. Then, (x−R) ² + y ² = (R + W / 2) ² (2) The straight line S _t representing the direction of the laser beam at time t is represented by y = xcot θ _t . (3) Therefore, the coordinates (x, y) of the intersection of the straight line S _t and the circular arc RL and the effective distance L _t are obtained from the equations (2) and (3) as follows. x = sin θ _t · {R _t ± √ (R _t ² + R · W + W ² /
4)} y = cos θ _t · {R _t ± √ (R _t ² + R · W + W ² /
_{4)} L t = R t} ± √ (R t 2 + R · W + W 2/4) ... (4) where where R _t = R · sinθ _t, of the formula (4), the value of y is negative L _t is S
_Since the extension line of _t represents the distance to the point where it intersects the arc RL at the rear of the vehicle, there is no need to consider it here, and in the end,
L _t can be found by _{L t = R t + √ (} R t 2 + R · W + W 2/4).

When β ≦ θ _t ≦ θ _max , the arc CL is expressed by the following equation (5). (X−R) ² + y ² = (R−W / 2) ² (5) Therefore, the coordinates (x, y) of the intersection of the straight line S _t and the arc CL and the effective distance L _t are given by the formula (3), From (5), the following is obtained. x = sin θ _t · {R _t ± √ (R _t ² −R · W + W ² /
4)} y = cos θ _t · {R _t ± √ (R _t ² −R · W + W ² /
_{4)} L t = R t} ± √ (R t 2 -R · W + W 2/4) ... (6) where, of the formula (6), the larger L _t is not necessary to consider, after all, L can be obtained by _{t = R t -√ (R t} 2 -R · W + W 2/4). As with the straight road,
Or a value of more resulting L _t is the L _t> L _max become scan angle theta _t, and L _t = L _max.

Next, a method of determining the maximum scanning angle θ _max will be described. The maximum scanning angle θ _max needs to be a scanning angle that can secure a sufficient detection range even in a curved road with a small radius of curvature R. Therefore, the maximum scan angle θ _max
It is necessary to contact the arc CL at a smaller angle as shown in FIG. Here, the tangent angle β is β as shown in equation (1).
= Cos ^-1 {1-W / 2R}, it is necessary to satisfy θ _max > cos ^-1 {1-W / 2R}. For example, consider a case where a general value W = 3.5 (m) is used as the lane width and R = 500 (m) as a curved road with a small radius of curvature. Maximum scan angle θ _max
The condition for contacting the arc CL at a smaller angle is θ _max > cos ⁻¹ {1-3.5 / (2 × 500)} =
Since 4.8 (°) is obtained, it can be determined that the maximum scanning angle θ _max = 5 (°).

From the following points, the maximum scanning angle θ _max needs to be about 5 °. 4, the distance between the intersection of the straight line SC and the curve RL and the point A in FIG. 3 is L ₁ , the distance between the intersection of the straight line SL and the curve RL and the point A is L ₂ , and the distance between the straight line SS and the curve RL is The distance between the intersection and point A is L ₃ , and the lane width W is 4
radius of curvature R and β, L ₁ , L ₂ , L when m
₃ shows the relationship of FIG. 3, and FIG. 5 is a graph showing this relationship. As can be seen from these figures, in order to ensure a detection distance of 100 (m) even on a curved road, the maximum scanning angle θ _max is 5 when the radius of curvature R is 500 m or more.
° Required. When this angle is increased, the detection pitch in the horizontal direction becomes coarse, so it is not preferable to increase it too much. For example, when detecting 50 times per horizontal scanning, when the maximum scanning angle θ _max is 5 °,
At the 100m point, the pitch is 0.35m. Therefore,
A maximum scanning angle θ _max of about 5 ° is suitable. However, since the optimum maximum scan angle changes depending on conditions such as lane width,
The maximum scanning angle may be changed according to conditions such as lane width.

As described above, the detection effective distance calculating unit 34 obtains the detection effective distance for each scanning angle and sends it to the obstacle determining unit 35. The obstacle determination unit 35 determines the angle
Only when the distance of the object detected by the distance detection unit 32 is within the effective detection distance at the scanning angle at which the object is detected, the object is determined as an obstacle. This judgment result is
It is used for alarms and speed control.

As described above, according to the present embodiment, the objects outside the traveling lane of the own vehicle, which do not need to be detected, are excluded from the objects to be detected, and only the objects which may collide with the own vehicle are detected. You can Further, in this embodiment, the radius of curvature is used when determining the effective detection distance, and this radius of curvature is calculated from the velocity and angular velocity of the host vehicle. There are other methods to detect the radius of curvature conventionally, such as steering angle, centrifugal force, roll angle, etc., but all of them are affected by the total weight of the vehicle, etc. Is difficult. On the other hand, in the present embodiment, since the radius of curvature is calculated from the velocity and the angular velocity of the host vehicle, the radius of curvature can be accurately detected without being affected by the total weight of the vehicle and the like. The effective detection distance can be accurately determined.

[0023]

According to the inventions of claims 1 to 3,
For example, since the maximum scanning angle is changed according to the width of the lane, a sufficient detection range can be secured even on a curved road with a small radius of curvature R. Further, according to the invention described in claims 2 and 3, it is possible to perform the accurate detection based on the radius of curvature and the width of the lane.
The intelligent effective distance can be determined, and as a result, an object that does not need to be detected can be excluded from the detection targets.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an obstacle detection device including a curvature radius detection device according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a state during traveling on a straight road in one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state during traveling on a curved road in one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between a radius of curvature, a maximum scanning angle, and a detection effective distance in one embodiment of the present invention.

5 is a characteristic diagram showing the relationship of FIG.

[Explanation of symbols]

11 laser 13 Condensing lens 14 Cylindrical lens 15 mirror 17 Condensing lens 19 Light receiving element 21 Speedometer 22 Angular velocimeter 32 Angle / distance detector 33 Radius of curvature calculator 34 Effective detection distance calculation unit 35 Obstacle determination unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-16484 (JP, A) JP-A-1-285815 (JP, A) JP-A-3-268110 (JP, A) JP-A-4- 232808 (JP, A) JP-A-3-111785 (JP, A) JP-A-59-203975 (JP, A) JP-A-3-92436 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G08G 1/16 G01S 17/93

Claims (3)

(57) [Claims] 1. A vehicle for setting a width of a lane in which the vehicle travels
Line width setting means and the maximum according to the lane width set by the lane width setting means
A scanning unit that scans an area within the scanning angle range to detect the direction and distance of an object existing in the area, an angular velocity detection unit that detects the angular velocity of the host vehicle, and a velocity detection unit that detects the velocity of the host vehicle. And a radius-of-curvature calculating means for calculating the radius of curvature of the lane in which the vehicle is traveling, based on the angular velocity detected by the angular velocity detecting means and the velocity detected by the velocity detecting means, and the radius-of-curvature calculating means. Based on the obtained radius of curvature, the detection effective distance calculating means for obtaining the detection effective distance for each scanning direction of the scanning means, and the distance of the object detected by the scanning means are within the detection effective distance in the direction of the object. If the object is an obstacle, the obstacle detection device is provided with an obstacle determination means for determining whether or not the object is an obstacle. 2. The detection effective distance calculation means is characterized in that the radius of curvature is
Curvature radius obtained by computing means and lane width setting
Each of the scanning means based on the lane width set by the means.
A contract characterized by obtaining a detection effective distance for each scanning direction
The obstacle detection device according to claim 1. 3. The lane width setting means is for running the own vehicle.
From the speed detected by the speed detection means,
Automatically set and use as navigation system map information
Lane width information obtained automatically and set automatically, or panel etc.
It is set according to the lane width input from
The obstacle detection device according to claim 1 or 2.