JP2728187B2 - Obstacle position 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 position detecting device, and more particularly to an obstacle object position detecting device suitable for being mounted on an unmanned vehicle.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional apparatus of this type. FIG. 2A shows a vehicle 2 traveling unmanned.
FIG. 4B is a plan view of the vehicle, and a camera 4 for photographing the front of the vehicle is provided above the front portion 6 of the vehicle 2. A laser radar 3 for detecting the obstacle 5 is provided.

[0003] While the vehicle is running, the camera 4 guides the vehicle 2 to travel within the two white lines 1 and 1 by photographing the two white lines 1 and 1, and the laser radar 3 moves the vehicle 2. When the obstacle 5 is detected at the position L ahead, the vehicle 2 is automatically stopped to prevent a collision.

[0004]

However, in the conventional apparatus as described above, the vehicle 2 is automatically stopped when the laser radar 3 detects an obstacle 5 in front of a predetermined distance L. Since the laser radar 3 can detect only the distance to the obstacle 5 and cannot detect the amount of deviation of the obstacle 5 in the lateral direction (indicated by the arrow A in FIG. 9B), the vehicle travels around the obstacle 5 Even if possible, there was a problem that it had to be stopped uniformly.

[0005] In this case, a large number of laser radars 3 may be provided, and the distance to the obstacle 5 may be measured by each laser radar 3 to detect the lateral displacement of the obstacle 5. However, in this case, a large number of laser radars must be provided, and there is a problem that the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an obstacle position detecting device capable of detecting a lateral displacement amount and not increasing the cost. Is to do.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is configured as shown in the claim correspondence diagram of FIG. 1 and is installed at a predetermined distance away from a front portion of a vehicle and projects a laser beam projected forward of the vehicle. A pair of laser radars a and a for detecting the distance to the obstacle f from the reflected waves of light, and when the obstacle f is detected ahead of the predetermined distance, the reception levels of the reflected waves are set to the respective laser radars a and a. Based on the reception level detection means b for each detection and the reception level of each laser radar a, a detected by the reception level detection means b, the installation position of each laser radar a, a is determined using fuzzy inference as a reference. A first lateral shift amount calculating means c for calculating a lateral shift amount of the obstacle f to be changed; a reception level for each of the laser radars a and a detected by the reception level detection means b; Lateral displacement amount calculating means c A second lateral displacement amount calculating means for computing a lateral displacement amount of the obstacle f from the center line in the vehicle traveling direction based on the computed lateral displacement amount, and the laser radars a and a; The distance to the obstacle
Obstacle position detecting means e for detecting the position of the obstacle f based on the lateral displacement calculated by the lateral displacement calculating means d;
It is characterized by having.

[0008]

According to the present invention, two laser radars for detecting the distance to an obstacle are installed at a predetermined distance from the front of the vehicle.

When an obstacle is detected ahead of a predetermined distance by the two laser radars, the reception level at that time is detected for each laser radar by the reception level detecting means, and the first lateral shift amount is further detected. The computing means computes the lateral shift amount of the obstacle based on the installation position of the laser radar based on the reception level detected for each laser radar for each laser radar using fuzzy inference.

In the second lateral displacement amount calculating means, the reception level of each laser radar detected by the reception level detecting means and the lateral displacement of each laser radar calculated by the first lateral displacement amount calculating means are calculated. The lateral displacement amount from the center line of the vehicle traveling direction is calculated based on the displacement amount, and the obstacle position detecting means detects the lateral displacement amount calculated by the second lateral displacement amount calculating means and is detected by the laser radar. The position of the obstacle is detected two-dimensionally based on information on the distance to the obstacle.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The same components as those used in the above-described conventional example are denoted by the same reference numerals and will be described.

FIG. 2 is a schematic diagram showing a schematic configuration of an embodiment to which the present invention is applied. FIG. 2 (a) is a side view of an unmanned vehicle 2 which can travel independently, and FIG. 2 (b) is a plan view thereof. is there.

First, the structure will be described. A camera 4 for photographing the front is mounted near the center of the upper part of the front part 6 of the vehicle 2, and a pair of laser radars 3A, 3B ( Laser radars a, a) are attached at a predetermined distance.

While the vehicle is running, the vehicle 4 is guided by the camera 4 for photographing the front so as to run along the white lines 1 and 1, and the obstacle 5 is detected forward by the pair of laser radars 3A and 3B. In such a case, the vehicle stops or makes a detour to the left or right.

FIG. 3 is a block diagram showing an electrical configuration of the apparatus of the embodiment shown in FIG.

In FIG. 1, a camera 4 captures white lines 1 and 1 in front of the vehicle (see FIG. 2).
Numeral 1 is for calculating the position coordinates of the white lines 1 and 1 and the tangent angle at each coordinate point from the photographing information.

The map information section 22 stores map information of a traveling route on which the vehicle travels, and stores information on a branch point in the middle of the traveling route.

Further, the traveling control unit 23 includes a map information unit 22.
The route to be traveled is determined based on the map information and the information from the laser radars 3A and 3B.

The steering angle control unit 24 calculates the steering angle based on the white line information sent from the image processing device 21 and the traveling route information sent from the traveling control unit 23.

The steering drive unit 25 drives an actuator (not shown) based on the steering angle information calculated by the steering angle control unit 24 to perform a steering operation.

The above is the configuration of the present embodiment. Next, when the obstacle 5 is detected in front of the vehicle, the traveling control unit 23
Will be described with reference to the flowchart shown in FIG.

First, while the vehicle is running, the two laser radars 3
A and 3B detect an obstacle in front of the vehicle. If an obstacle 5 is detected in front of the vehicle, the distances LA and LB to the obstacle 5 are detected by the two laser radars 3A and 3B.
Is started (step 400), and it is checked whether or not the distance between the vehicle 2 and the obstacle 5 ahead approaches a predetermined value Lob (step 402).

Referring now to FIG. 5, a pair of laser radars 3A and 3B are respectively located at predetermined positions spaced a from the center P of the front portion 6 of the vehicle 2 in the vehicle width direction.
Is provided. Based on the distances LA and LB from the laser radars 3A and 3B to the obstacle 5 in front of the vehicle, (L
A + LB) / 2 is set as the distance to the obstacle 5, and it is checked whether or not this value approaches a predetermined value Lob.

When it is detected that (LA + LB) / 2 = Lob (YES in step 402),
Next, the reception levels mA and mB of the laser radars 3A and 3B at that time are detected (step 404). This corresponds to the reception level detecting means in claim 1.

FIG. 5 shows the reception level mA detected by the laser radar 3A and the reception level mB detected by the laser radar 3B. The reception level m detected is determined by each of the laser radars 3A and 3A. It is represented by a normal distribution having the front position of 3B (indicated by -a and a in the figure) as a peak value. This is because, in the laser radar, the azimuth resolution of the directional curve of sensing is affected by noise.

Therefore, the lateral displacement x of the obstacle 5 viewed from each of the laser radars 3A and 3B is calculated as shown in FIG.
x | = f (M) (where M = mA / α or mB / α
, Α is a constant), and further divides this nonlinear function into a fuzzy set as shown in FIG. 7 and attempts to detect the lateral displacement x of the obstacle using fuzzy inference. This is the processing after 406.

The lateral displacement x of the obstacle is represented by a function as shown in FIG. 6. For example, this function cuts a reflected wave at a fixed threshold level in a general laser radar device. Can be varied or the constant α can be adjusted.

Further, although divided into fuzzy set as shown in FIG. 7 is a function shown in FIG. 6 (membership functions), which is the reception level M and the deviation amount | x | a S ₀ has a plurality of labels, respectively - it is obtained by dividing the fuzzy function of S ₆ and T _o through T _6.

Then, for example, a rule such as if M = Si then | x | is Tj (where i = 0 to 6, j = 0 to 6) is created, and the well-known MINI-M
The deviation amount | x | is to be obtained by the AX method.

That is, the two laser radars 3A and 3B
When the reception waves of the reception levels mA and mB are detected from
= MA / α or mB / α, the reception level mA, m
A rule having B as an input value is selected from rules prepared in advance, and output values RA (n) and RB (m) for each rule are obtained (step 406).

Then, the calculated output values RA (n), R
From B (m), weighted weighted average values (xA) and (xB) are obtained by the MINI-MAX method, and are set as deviation amounts | x | (step 408). Steps 406 and 408 described above correspond to the first lateral displacement amount calculating means in claim 1.

The above is the calculation process of the deviation amount | x | of the forward obstacle based on the installation positions of the laser radars 3A and 3B using fuzzy inference.
Only the absolute value of the shift amount from the position with reference to a and a is obtained, and it is not known whether the shift amount is left or right.

Therefore, in the following processing, the reception levels mA and m detected by the two laser radars 3A and 3B are used.
Based on the magnitude of B, it is determined whether the displacement is left or right, and the lateral displacement x of the obstacle is detected.

That is, as shown in FIG. 5, when the point in front of the center P of the vehicle 2 by the distance Lob is the origin 0 and the center line in the vehicle traveling direction is PO, the lateral displacement x from the origin 0 is as follows. Required.

That is, first, it is checked whether or not mA> mB (step 410). (1) If mA> mB, mB = 0 (steps 410 and 4)
12, YES), x = −a− | xA | (step 414), (2) If mA> mB, mB ≠ 0 (Y in step 410)
ES, No at step 412), x = −a + | xA | (step 316), (3) If mA ≦ mB, mA ≠ 0 (steps 410 and 4)
18, No), and x = a− | xB | (step 420). (4) If mA ≦ mB, mA = 0 (N at step 410
o, YES at 418), x = a + | xB | (step 422). The above steps 410 to 422 are the second steps in claim 1.
Corresponds to the lateral displacement amount calculating means.

When the lateral displacement x of the obstacle about the center line PO of the vehicle is detected in this way, the position of the obstacle is obtained by the coordinates (x, Lob) (step 424). . This step 424 corresponds to the obstacle position detecting means in claim 1.

Next, FIG. 8 shows the lateral displacement amount x as described above.
3 shows a traveling route of the vehicle 2 when the obstacle 5 is detected at the position of the front Lob of the vehicle 2.

That is, in this case, assuming that the center line in the traveling direction of the vehicle 2 is PO and the points on the x-axis separated by a fixed distance d from the origin 0 are 1 d and d, the steering angle control unit 24
Is (1) R1 route avoiding right if x <-d, (2)
If x> d, avoid R2 route to the left, (3) -d ≦ x ≦ d
If so, a signal is output to the steering drive unit 25 so as to stop without steering.

As the steering angle control section 24, for example, a steering angle calculation means described in Japanese Patent Application Laid-Open No. 64-7110 is used.

As described above, the apparatus of this embodiment uses the two laser radars 3A and 3B, and when the obstacle 5 is detected ahead of the predetermined distance Lob, fuzzy inference is performed from the reception level of the reception wave at that time. Using the vehicle center line P of the obstacle 5
Since the lateral displacement amount from O is calculated and the plane coordinate position of the obstacle 5 is detected by this, not only the distance information to the obstacle 5 but also the azimuth information can be obtained.

Therefore, when an obstacle is detected ahead, not only can the vehicle be stopped uniformly as in the prior art, but also the vehicle can make a detour to the left or right while avoiding the obstacle, and can travel more efficiently to the destination. Has an effect.

Also, since the lateral displacement of an obstacle can be detected by only two laser radars, this type of cost can be reduced at a lower cost compared to a method of detecting the lateral displacement by combining a large number of laser radars. There is also an effect that a device can be obtained.

In this embodiment, the distance to the obstacle is detected by using the laser radar. However, it goes without saying that a distance measuring device such as a radio wave radar or an ultrasonic sensor can be used.

[0044]

As described above, according to the present invention, 2
Two laser radars are used to detect the position of an obstacle ahead two-dimensionally using fuzzy inference from the reception level of the distance information, so even if an obstacle is detected ahead, It is also possible to select a detour to the left or right without stopping, so that more efficient traveling can be performed even when the vehicle is mounted on an unmanned vehicle.

Since only two laser radars are provided, this type of apparatus can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a configuration of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of an embodiment to which the present invention is applied.

FIG. 3 is a block diagram showing an electrical configuration of the embodiment shown in FIG. 2;

FIG. 4 is a flowchart illustrating the operation of the embodiment of the present invention.

FIG. 5 is an explanatory diagram of a case where two laser radars are installed and a reception level of a reception wave from an obstacle is detected for each laser radar.

FIG. 6 is a characteristic diagram showing a relationship between a reception level of a reception wave and a lateral shift amount.

FIG. 7 is an explanatory diagram when the characteristic diagram shown in FIG. 6 is divided into fuzzy functions.

FIG. 8 is an explanatory diagram showing a vehicle traveling method when an obstacle is detected ahead.

FIG. 9 is a schematic diagram showing a schematic configuration of this type of device in a conventional example.

[Explanation of symbols]

 a Laser radar b Receiving level detecting means c First lateral displacement amount calculating means d Second lateral displacement amount calculating means e Obstacle position detecting means f Obstacle 1 White line 2 Vehicle 3A, 3B Laser radar 4 Camera 5 Obstacle 6 Front unit 31 Image processing device 32 Map information unit 33 Travel control unit 34 Steering angle control unit 35 Steering drive unit

Claims (1)

(57) [Claims] A pair of laser radars installed at a predetermined distance apart from each other at a front portion of a vehicle and detecting a distance to an obstacle from a reflected wave of laser light projected forward of the vehicle; In this case, the reception level of the reflected wave is detected for each laser radar, and the reception level of each laser radar detected by the reception level detection means is used for each laser radar using fuzzy inference. A first lateral displacement amount calculating means for calculating a lateral displacement amount of the obstacle based on the installation position of the obstacle; a reception level for each laser radar detected by the reception level detection means; A second lateral displacement calculator for calculating a lateral displacement of the obstacle from the center line in the vehicle traveling direction based on the lateral displacement calculated by the lateral displacement calculator; Obstacle position detecting means for detecting the position of the obstacle based on the predetermined distance to the determined obstacle and the lateral displacement calculated by the second lateral displacement calculating means. Obstacle position detection device.