JPH07160331A - Position self-detecting method for autonomous traveling working vehicle - Google Patents

Abstract

PURPOSE:To accurately detect a local position at all times without being affected by the distance between the vehicle and a marker by adjusting the focus of an image pickup means so that the area of the marker in a picked-up image reaches reference area and expanding a marker detection range. CONSTITUTION:Information regarding the apparent are of the marker in an image pickup screen, i.e., picked-up marker area is compared with a marker area reference value which is previously set to an optimum value so that stable marker recognition is enabled to judge whether or not the picked-up marker area is equal to the marker area reference value. Then when the picked-up marker area is larger, a motor for adjusting the focus of a CCD camera 8s is moved with a previously set controlled variable to move the focus away, thereby increasing luminance per unit area. When the picked-up marker area is smaller to the contrary, the focus adjusting motor of the CCD camera 8a is moved with the previously set controlled variable to move the focus in the near direction, and the marker is photographed large intentionally in an out-of-focus state. Consequently, the marker can securely be recognized by the CCD even in a state wherein the marker is positioned distantly exceeding the focus range wherein a sharp image is obtained by the CCD camera 8a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the self-position of a plurality of markers installed around a specific work area, detects the self-position, and self-positions an autonomous traveling work vehicle for carrying out work traveling in grass cutting, lawn mowing, etc. It relates to a detection method.

[0002]

2. Description of the Related Art In recent years, autonomous traveling work vehicles have been developed which are capable of unmanned grass cutting, lawn mowing and the like in various fields such as golf courses, river banks, parks and the like. In the autonomous traveling control of this autonomous traveling work vehicle, there is one that employs a technique of detecting a self position by using a sign erected around the work area. For example, Japanese Patent Laid-Open No. 3-135606 discloses Light is projected onto a plurality of retroreflective poles (light reflective markers) installed upright in the area, the reflected light is received by an optical sensor, and the angle facing the adjacent reflective poles is detected. A technique of detecting a self-position from coordinates and a three-point included angle method (triangulation method) is disclosed.

In this case, in the technique of detecting a sign by an optical sensor, if the work area has uneven terrain or swell, the projected light beam may deviate from the sign due to the influence of the inclination of the vehicle, the vibration of the vehicle, or the like. Since it may be difficult to receive the reflected light from the sign, recently, a technique has been proposed in which the sign is recognized and the self-position is detected by imaging the surrounding scenery including the sign and processing the image. However, for example, in Japanese Unexamined Patent Publication No. 3-71312, in automatic steering control of an agricultural tractor, an index (sign) is photographed by a camera mounted on the agricultural tractor, and its image recognition position with respect to a set reference position. A technique for detecting the self-position based on the displacement is disclosed.

[0004]

However, in general, when recognizing a sign from a picked-up image, a large amount of image information is required. Therefore, the sign should be recognized from a clear picked-up image focused on the sign. However, there is a limit to the range in which a clear captured image can be obtained by an image capturing means such as a normal camera.

Therefore, in a situation where the sign is located far from the vehicle, the sign becomes too small in the captured image to make it difficult to see, and there is insufficient information for extracting the sign from the captured image. You may lose sight of the sign.

The present invention has been made in view of the above circumstances, and an autonomous traveling work capable of always detecting the self-position accurately by expanding the sign detection range and being not affected by the distance between the vehicle and the sign. It is an object of the present invention to provide a vehicle self-position detecting method.

[0007]

SUMMARY OF THE INVENTION The present invention is a self-propelled vehicle for self-propelled vehicles that images a plurality of signs installed around a specific work area, recognizes the signs from the picked-up images, and detects the self-position by triangulation. In the position detection method, the area of the marker on the captured image is compared with a preset reference area, and the focus of the image pickup means is adjusted so that the area of the marker on the captured image becomes the reference area to determine the marker detection range. It is characterized by expanding.

[0008]

In the present invention, the area of the sign on the image of the landscape including the sign is compared with a preset reference area, and the focus of the image pickup means is adjusted so that the area of the sign on the captured image becomes the reference area. Adjust to make the distant sign larger,
Expand the detection range for distant signs.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The drawings relate to one embodiment of the present invention. FIG. 1 is a flowchart of an imaging control routine, FIG. 2 is a flowchart of a main control routine, FIG. 3 is a flowchart of a self-position detection routine, and FIG. Illustration,
5 is a block diagram of a control system, FIG. 6 is a circuit configuration diagram of a vehicle position detection unit, FIG. 7 is an explanatory diagram showing a travel route and a work area, and FIG. 8 is an explanatory diagram of self-position detection by triangulation.

In FIG. 4, reference numeral 1 indicates an autonomous traveling work vehicle which is capable of autonomous driving by an unmanned vehicle, and in the present embodiment is a lawn mowing work vehicle for performing grass and lawn mowing work on a golf course or the like. This lawnmower vehicle 1 is driven by an engine, and the steering angles of the front and rear wheels can be independently controlled.
In the lower part of the vehicle body, a cutting blade mechanism 2 such as a mower for performing grass / lawn mowing work is provided, a dead reckoning sensor for measuring the current position based on the traveling history, and a traveling obstacle for detecting an obstacle. A sensor for detecting obstacles, a sensor for profile travel for performing profile travel along the cutting boundary in the grass / lawn mowing work area, etc. are installed, and a plurality of markers standing upright around the grass / lawn mowing work area. It is provided with an image pickup means for picking up an image, recognizing the sign from the picked-up image, and detecting the self-position by triangulation.

As the dead reckoning sensor, a geomagnetic sensor 3 and a wheel encoder 4 are provided in the lawnmower work vehicle 1, and as the obstacle detecting sensor, a non-contact type including an ultrasonic sensor or an optical sensor. Sensors 5a, 5b
Are attached to the front and rear parts of the lawn mowing work vehicle 1, and a contact type sensor 6a using a micro switch or the like,
6b are attached to the front and rear ends of the lawnmower working vehicle 1.

Further, as the copying traveling sensor, for example, a sled plate which moves up and down according to the length of grass and grass and a rotary encoder which detects a rotation angle of a member which supports the sled plate are combined. In addition, a cut mark boundary detection sensor 7 for detecting a cut mark boundary between the already cut portion and the uncut portion is provided at the lower portion of the vehicle body of the lawnmower work vehicle 1.

As an image pickup means for picking up an image of a sign, for example, a CCD using a solid-state image pickup device (CCD)
A camera is used. This CCD camera is an image pickup unit 8 integrated with an illumination light for covering the field of view of the CCD camera on a rotating mechanism portion 10 standing upright on the front side of the lawn mowing vehicle 1, and has an image pickup surface perpendicular to the mounting axis. It is mounted with the camera facing to, and is rotated by 360 ° with respect to the mounting shaft so that imaging can be performed on the entire circumference. Further, the CCD camera has a lens focus and aperture adjustment mechanism built in the camera lens portion, and as described later, the focus and aperture are controlled for a distant sign to expand the sign recognition ability. You can do it.

The above-described self-position detection / autonomous traveling control in the lawnmower work vehicle 1 is performed by the control device 30 shown in FIG. 5, and this control device 30 is composed of a detection part and a control part which are composed of a plurality of microcomputers. To be done.

As a detection section for processing the signals of the respective sensors and actuators, a vehicle position detection section 31, a cut boundary detection section 35, and an obstacle detection section 36 are provided, and the detection sections 31, 35 are provided. , 36 as a control unit for performing control based on signals from the vehicle, a traveling control unit 37 for performing traveling control, and a work data storage unit 3 in which a work data map referred to by the traveling control unit 37 is stored.
8. A vehicle control unit 39 for controlling the vehicle in accordance with an instruction from the traveling control unit 37 is provided. Further, based on the output from the vehicle control unit 39, each mechanical unit of the lawnmower working vehicle 1 is driven. A control unit 40, a steering control unit 41, and a cutting blade control unit 42 are provided.

Further, the vehicle position detecting section 31 integrates the vehicle speed detected by the wheel encoder 4 to obtain a traveling distance, and makes this traveling distance correspond to a change in traveling direction detected by the geomagnetic sensor 3. The dead reckoning position detection unit 32 that calculates the traveling history from the reference point and measures the current position of the vehicle by accumulating the accumulated data, and various signals for imaging by the CCD camera 8a of the imaging unit 8, that is, An electronic shutter control signal, a focus control signal, a diaphragm control signal for the CCD camera 8a, a drive signal for the illumination light 8b, and a drive signal for a rotation drive motor 11 such as a step motor or a servo motor built in the rotation mechanism section 10 are provided. Sign imaging control unit 33 for outputting
And a video signal from the CCD camera 8a is processed to recognize a plurality of markers, a rotation angle signal from a rotation angle sensor 12 attached to the rotation mechanism section 10, and positioning from the dead reckoning position detection section 32. A triangulation position detection unit 3 that compares the data and the position data of each sign that has been stored in advance to identify each sign and detects the self-position based on the triangulation principle from the position data of the sign that is stored in advance.
4 and.

On the other hand, the cut boundary detection unit 35 processes the signal from the cut boundary detection sensor 7 according to the grass / turf height to detect the grass / turf boundary position. As described above, the cut boundary detecting sensor 7 is composed of a sled-shaped plate that moves up and down according to the length of grass / turf, and a rotary encoder that detects a rotation angle of a member that supports the sled-shaped plate. If so, grass
When the vertical displacement of the sled-shaped plate corresponding to the lawn height is converted into a rotation angle and a detection signal is input from the rotary encoder, the cut boundary detection unit 35 uses the detection signal to detect grass and lawn mowing work. The cut area boundary is detected by distinguishing the completed area and the unworked area, and the position data is output to the traveling control unit 37.

The obstacle detecting section 36 detects an unpredictable obstacle by the non-contact type sensors 5a, 5b and the contact type sensors 6a, 6b, and outputs a detection signal to the traveling control section 37.

The traveling control unit 37 stores work data based on the information from the dead reckoning position detecting unit 32, the triangulation position detecting unit 34, the cut mark boundary detecting unit 35, and the obstacle detecting unit 36. The amount of error between the current position of the user and the target position is calculated by referring to the map of the section 38 (the work content and the map for traveling such as the terrain data of the work area where grass and lawn mowing work are performed), and this error amount is calculated. A travel route instruction and a vehicle control instruction are determined to be corrected and output to the vehicle control unit 39.

The vehicle control unit 39 converts the instruction from the traveling control unit 37 into a specific control instruction amount, and the control instruction amount is drive control unit 40, steering control unit 41, cutting blade control unit 42. Output to. Accordingly, the drive control unit 4
At 0, the hydraulic motor 13 is driven to generate hydraulic pressure for driving each mechanism section of the lawnmower working vehicle 1, and the steering control section 41 is operated.
Then, the front wheel steering mechanism and the rear wheel steering mechanism (not shown) are servo-controlled via the front wheel steering hydraulic control valve 14 and the rear wheel steering hydraulic control valve 15, respectively, and the cutting blade control section 42 The cutting blade mechanism 2 is servo-controlled via the cutting blade control hydraulic control valve 16.

FIG. 6 shows a concrete circuit configuration of the vehicle position detecting section 31. The CPU 50 has a RAM 51 for holding work data and the positions of markers installed around a specific area to be worked. RO that stores data and other fixed data for control, and control program
I / O for input / output of M52, various data and control signals
The O interface 53 is mainly composed of a microcomputer connected via a data bus 54 and an address bus 55, and when an image picked up by the CCD camera 8a is processed to perform self-position detection by triangulation,
By controlling the focus and aperture of the CCD camera 8a and expanding the sign recognition ability even when the sign is distant, accurate vehicle position detection is always realized.

That is, the CPU 50 executes the programs of the image pickup control routine of FIG. 1 and the self-position detection routine of FIG.
After outputting the focus control signal and the aperture control signal from the CCD camera 8a to the focus adjustment motor and the aperture adjustment motor, respectively, to set the lens focus and the aperture, the I / O interface 53 drives the motor drive circuit 56 and the light. A control signal is output to the drive circuit 57 to turn on the illumination light 8b, and the rotation drive motor 11 drives the rotation mechanism unit 10 to drive the illumination light 8b and the CCD camera 8a.
Is rotated and an electronic shutter control signal is output to the CCD camera 8a at every set time interval to capture an image of the entire circumference.

The image taken by the CCD camera 8a is NTS
It is sent to the amplifier 58 as a C type video signal, amplified and supplied to the synchronizing circuit 59 and the AD converter 60, respectively. The synchronizing circuit 59 separates the synchronizing signal from the video signal to generate a timing signal and supplies it to the AD converter 60 and the address control circuit 61.

The AD converter 60 converts the video signal from the amplifier 58 into digital image data in synchronization with the timing signal and outputs it to the switching circuit 64 via the data bus 62. Further, the address control circuit 61 generates address data in synchronization with the timing signal and supplies it to the switching circuit 64 via the address bus 63.

The switching circuit 64 selectively connects either one of the data bus 54 and address bus 55 on the CPU 50 side and the data bus 62 and address bus 63 on the AD converter 60 side to the video memory 65. Yes, while the address data is being supplied from the address control circuit 61 to the switching circuit 64, the data bus 6 on the AD converter 60 side is provided.
2 is connected to the video memory 65 so that the image data can be written.
Access to 5 is prohibited.

When the supply of the video signal from the CCD camera 8a is stopped and the video memory 65 of the CPU 50 can be accessed, the image data is read from the video memory 65, the image data is processed, and the work area is processed. After a plurality of surrounding signs are recognized, each sign is identified based on each signal from the geomagnetic sensor 3, the wheel encoder 4, and the rotation angle sensor 12 read via the I / O interface 53, and triangulation is performed. The position of the vehicle is calculated by the I / O interface 53 and the traveling control unit 37 is operated.
The vehicle position information is output to.

Hereinafter, for the work area as shown in FIG.
Explain the case where unmanned grass and lawn mowing work is performed. In this case, the lawn mowing vehicle 1 is assumed to have been moved in advance by manned operation from an arbitrary preparation position 70 to the grass / lawn mowing start point 74 in the work area 72 before starting work. Lawn mowing work is shown in Figs. 1 and 2.
It is performed autonomously according to the program shown in the flow chart. Then, after the work is completed, the work is moved from the work end point 75 to the standby position 78 again by manned driving.

In FIG. 7, reference numerals PA, PB, PC
Is a sign installed in advance around the work area 72 and is a light reflection type sign in the present embodiment, but it may be a self-luminous type sign. In that case, the illumination light in the imaging unit 8 is used. 8b is unnecessary.

FIG. 2 shows a main control routine executed by the traveling control unit 37. In this main control routine, first in step S101, the image pickup control routine of FIG.
When the self-position detecting routine is executed by the self-vehicle position detecting unit 31, the signs PA, PB, and PC are recognized and the self-position is measured by triangulation, the lawn mowing vehicle 1 reaches the starting point 74 of the grass and lawn mowing work. Is confirmed, step S102
Then, the hydraulic control valve 16 for controlling the cutting blade is opened to cut the cutting blade mechanism 2
Hydraulic pressure is supplied to the blade to activate the cutting blade and start grass and lawn mowing work.

Next, the process proceeds to step S103, and the lawn mowing work is 1
It is checked whether or not it is the first time, and if the work is the first stroke (first column), the process proceeds to step S104, and if it is the second or later second column, the process branches to step S109.

This is the first operation, and when the process proceeds from step S103 to step S104, the vehicle position detecting section 31 again executes the image capturing control routine and the self position detecting routine, and the vehicle of the vehicle is subjected to triangulation and dead reckoning. After detecting the position and the traveling direction, in the subsequent step S105, the work data storage unit 38 is referred to, and the amount of error from the current position is obtained with the end point position of the first time (first row) in the work area 72 as the target position.

Next, when the process proceeds to step S106,
Each target steering amount of the front and rear wheels is determined according to the error amount obtained in S105, and in the subsequent step S107, the front wheel steering mechanism is operated via the front wheel steering hydraulic control valve 14 and the rear wheel steering hydraulic control valve 15. The rear wheel steering mechanism is driven to control the target steering angle.

Then, in step S108, it is checked whether or not the lawnmower work vehicle 1 has reached the end point position of the first time (first row),
When the end point position is not reached, the above-mentioned step S104
Return to and continue grass and lawn mowing work, and when the end point is reached,
In step S116, it is checked whether or not all the work has been completed. In this case, since it is the first work, the above steps
Returning to S103, it is checked again whether or not the work is the first time. When the work is the second time or later, the process branches to step S109, and the work route 73 along the cut boundary is followed.

That is, in step S109, when the vehicle body is laterally shifted by the width of the cutting blade and moved to the next work position, the cut mark boundary detection sensor 7 detects the cut mark boundary by the previous work in step S110, and in step S111. , The amount of error for realizing the set lawn mowing overlap amount is calculated by comparing the cut mark boundary with the vehicle position.

In the following step S112, the above step S111
Each target steering amount of the front and rear wheels is determined according to the error amount obtained in step S113, and in step S113, the front wheel steering hydraulic control valve 1
4, front wheel steering mechanism via the rear wheel steering hydraulic control valve 15,
The rear wheel steering mechanism is driven to control the target steering angle.

After that, the process proceeds to step S114, where the vehicle position detecting section 31 executes the imaging control routine and the self position detecting routine to detect the vehicle position and the traveling direction of the vehicle by triangulation and dead reckoning, and then in step S115. , It is checked whether the lawnmower 1 has reached the end point position after the second time (after the second row).

When the end point position has not been reached, the process returns from step S115 to step S110 described above to continue the contour traveling along the cut boundary, and reaches the end point position after the second time (after the second row). Then, the process proceeds from step S115 to step S116, and it is determined whether or not the grass / lawn mowing work in the work area 72 is completed.

As a result, if the grass / lawn mowing work in the work area 72 is not finished, the process returns from step S116 to step S103 to continue the work, and when the grass / lawn mowing work in the work area 72 is finished, this main control routine Stop grass and lawn mowing work by and stop the vehicle.

Next, the image pickup control processing and the sign recognition processing of the CCD camera 8a will be described. These processes are multitasks of the image pickup control routine and the self-position detection routine that are executed by the CPU 50 of the vehicle position detection unit 31 in a time-division manner, and when the CCD camera 8a images the surrounding scenery including the sign, The focus and diaphragm of the CCD camera 8a are controlled, and the detection range is expanded even for a distant sign.

First, the self-position detecting routine shown in FIG. 3 will be described. In step S201, the illumination light 8b is turned on via the light driving circuit 57 to turn on the motor driving circuit 5.
The motor 11 is driven via 6 and the image pickup unit 8 (illumination light 8b and CCD camera 8a) is rotated at a set speed via the rotation mechanism section 10.

Next, in step S202, an imaging time interval at which a blind spot is not obtained is obtained from the rotational speed of the CCD camera 8a and the lateral viewing angle of the CCD camera 8a, and the electronic camera of the CCD camera 8a is determined for each imaging time interval. The shutter is triggered to capture the surrounding landscape over the entire circumference, and the AD converter 6
When it is 0, it is converted into a digital signal and written in the video memory 65.

When the writing of the image data into the video memory 65 is completed, the switching circuit 64 causes the CPU 50 to
Since the video memory 65 can be accessed by
In step S203, the captured image data is read, the feature information corresponding to the marker is obtained from the brightness information and color information of the read captured image, or the shape or the like to recognize the marker, and as marker recognition information for an imaging control routine described later. The individual markers PA, PB, and PC are stored while being stored in the RAM 51.

That is, each of the markers PA, PB, and PC is used as a light-reflective marker in which, for example, a retroreflector is applied over a predetermined length, the brightness of the marker image pickup portion is increased, and the image is binarized to mark the marker. After the extraction, by comparing the position of the current position estimated by dead reckoning with the position of the previously stored sign, the individual signs can be identified. Alternatively,
Further, for example, by setting each of the markers PA, PB, and PC to have different colors, the markers can be extracted and identified from the color information of the captured image. Furthermore, for example, the shapes of the markers PA, PB, and PC are made different, and it is checked whether or not the shape extracted based on the brightness information of the captured image matches the shape of the stored individual markers. , Individual signs can be identified.

In this case, since the image obtained from the CCD camera 8a has the angle of view in the horizontal and vertical directions,
It is possible to reliably recognize the sign without losing sight of the sign due to the inclination of the vehicle or the vibration of the vehicle itself in a work area with uneven terrain or undulations.

Next, in step S2O4, the center of gravity on the recognized image of the sign and the image of each image of the lawn mowing vehicle 1 obtained by the rotation angle signal from the rotation angle sensor 12 attached to the rotation mechanism 10 are taken. The direction of each sign is calculated from the camera angle, and the angle α formed by the sign PA and the sign PB centering on the vehicle and the angle β between the signs PB and PC are calculated and stored in advance in the sign PA. , PB,
When the current vehicle position is calculated from the PC position by the well-known triangulation method, the calculated self-position data is calculated in step S2.
At 05, it is sent to the traveling control unit 37 and the process returns to step S202.

That is, as shown in FIG. 8, in the X, Y coordinate system having the marker PA as the origin, the distance from the marker PA (coordinate origin) to the center position of the vehicle is based on each data stored in the ROM 52 in advance. The distance L and the angle θ1 formed by the line connecting the center of the vehicle from the marker PA (coordinate origin) and the line connecting the markers PA and PB are calculated by the following equations (1) and (2), and the vehicle position ( X1, Y1) can be calculated by the equations (3) and (4). L = L1 × sin (α + θ1) / sinα (1) θ1 = atn (-L2 × sinα × sin (θB + α + β) / (L1 × sinβ + L2 × sinα × cos (θB + α + β))) (2) L1; Label PA, Distance between PBs L2; Distance between signs PB and PC θB; Angle formed by line connecting signs PA and PB and line connecting signs PB and PC θA; Angle of line connecting signs PA and PB with respect to X axis X1 = L × cos (θA−θ1) (3) Y1 = L × sin (θA−θ1) (4)

On the other hand, in the image pickup control routine of FIG. 1 which is executed in a time-sharing manner with this self-position detection routine, first, in step S301, the motor of the camera lens portion of the CCD camera 8a is controlled to preliminarily display all the markers. On the other hand, fix the focus / aperture position set to an appropriate value.

Next, in the state where the image pickup unit 8 is rotated by the above-mentioned self-position detection routine, the sign is imaged in step S302 and stored in the RAM 51 in step S203 of the above-mentioned self-position detection routine in step S303. The sign recognition information is read to obtain information about the apparent area of the sign on the image pickup screen, that is, the image pickup sign area, and luminance (average value) information at the image pickup sign area, that is, the image pickup sign luminance.

Next, the process proceeds to step S304, and the step
The imaged marker area obtained in S303 is compared with the marker area reference value set in advance to an optimum value for stable marker recognition, and in step S305, whether the imaged marker area and the marker area reference value are equal or not. If so, the process jumps to step S308, if larger, to step S306, and if smaller, to step S307.

When the imaged sign area is larger than the sign area reference value and the process proceeds to step S306, CC is applied to the sign.
Since the focus of the D camera 8a is on the short distance side and the sign is out of focus and the sign looks too large, the brightness per unit area is low and the sign is likely to be erroneously recognized. Therefore, in step S306, the focus is moved in the far direction by moving the focus adjustment motor of the CCD camera 8a by a preset control amount, the brightness per unit area is increased, and the process proceeds to step S308.

When the image-pickup sign area is smaller than the sign-area reference value and the process proceeds to step S307, the CCD camera 8a focuses on a sign located far away, and the sign looks too small on the image-pickup screen. Since it is in a difficult state, there is a risk that the information for extracting the sign from the captured image is insufficient and the sign is lost. Therefore, in step S307,
By moving the focus adjustment motor of the CCD camera 8a with a preset control amount, the focus is moved in the near direction to intentionally defocus the mark so that a large image can be obtained, and the process proceeds to step S308.

In step S308, the image pickup sign luminance obtained in step S303 is compared with the sign luminance reference value preset to an optimum value for stable sign recognition, and in step S309, the image pickup sign luminance is set. Is equal to the sign brightness reference value. That is, when the focus is moved to increase or decrease the area of the imaged sign, the brightness per unit area also increases or decreases according to the increase or decrease, and therefore it is determined whether or not the brightness is suitable for sign recognition.

When the imaged marker brightness is equal to the marker brightness reference value, the process returns to step S302 and the same process is repeated. When the imaged marker brightness is brighter than the marker brightness reference value, the process proceeds from step S309 to step S310 in advance. The aperture is stopped by moving the aperture adjusting motor of the CCD camera 8a with the set control amount, and the process returns to step S302.

If the image pickup sign luminance is darker than the sign luminance reference value, the process proceeds from step S309 to step S311.
The aperture is opened by moving the aperture adjustment motor of the CCD camera 8a with a preset control amount, and the above-mentioned steps are performed.
Return to S302.

As a result, the marker P is attached to the lawnmower work vehicle 1.
All or part of A, PB, PC is CCD camera 8
Even in a situation in which a clear image is obtained by a and the subject is located far away from the focal range, information for recognizing the sign can be secured on the captured image, and the sign can be surely recognized. Can be done.

In steps S306 and S307, the focus adjustment motor is moved by a control amount according to the difference between the image-pickup marker area and the marker-area reference value, and in steps S310 and S311, the aperture-adjustment motor is changed to the image-pickup marker. You may make it move with the control amount according to the difference of brightness | luminance and a sign brightness | luminance reference value.

[0057]

As described above, according to the present invention, the area of a sign on a captured image is compared with a preset reference area,
In order to adjust the focus of the imaging means so that the area of the sign on the captured image becomes the reference area so that the distant sign can be seen large, the detection range for the distant sign is expanded and the distance between the vehicle and the sign is increased. An excellent effect is obtained such that the self-position can always be detected accurately without being affected.

[Brief description of drawings]

FIG. 1 is a flowchart of an imaging control routine.

FIG. 2 is a flowchart of a main control routine.

FIG. 3 is a flowchart of a self-position detection routine.

FIG. 4 is a schematic explanatory view showing the appearance of a lawnmower work vehicle.

FIG. 5 is a block diagram of a control system

FIG. 6 is a circuit configuration diagram of a vehicle position detection unit.

FIG. 7 is an explanatory diagram showing a travel route and a work area.

FIG. 8 is an explanatory diagram of self-position detection by triangulation.

[Explanation of symbols]

 1 Lawn mowing work vehicle (autonomous traveling work vehicle) 8a CCD camera (imaging means) PA, PB, PC sign

Claims (1)

[Claims] 1. A self-position detecting method for an autonomously traveling work vehicle, which picks up a plurality of signs installed around a specific work area, recognizes the signs from the picked-up image, and detects the self-position by triangulation. The area of the sign above is compared with a preset reference area, and the focus of the imaging means (8a) is adjusted so that the area of the sign on the captured image becomes the reference area, thereby expanding the sign detection range. A method for detecting the self-position of an autonomous vehicle.