JPH07160330A - Position self-detecting method for autonomous traveling working vehicle - Google Patents

Abstract

PURPOSE:To recognize a marker without being affected by the slanting and vibration of the vehicle in an uneven or undulating area and perform position self-detection by finding the feature quantity of the marker from plural images picked up at specific time intervals and recognizing the marker. CONSTITUTION:When a light 8b for lighting is turned ON through a light driving circuit, a motor 11 is driven through a motor driving circuit and the light 8b and a CCD camera 8a Are rotated at a set speed through a rotating mechanism part. An image pickup time interval which generates no dead angle is found from the rotating speed of the CCD camera 9a and the lateral field angle of the CCD camera 8a, the electronic shutter of the CCD camera 8a is triggered at intervals to pick up images of the whole circumferential scenery of 360 deg., and the feature quantity corresponding to the marker is found from luminance information and color information on the picked-up images or shapes, etc., to detect the marker. After all markers are recognized, local position data generated by calculating the current vehicle position by known trigonometry from the previously stored positions of the respective markers are sent out to a travel control part 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention recognizes a plurality of signs installed around a specific work area to detect its own position, and performs self-positioning of 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 Conventionally, for an autonomous vehicle that is autonomously autonomously traveling, there is a technique in which an electric wire is buried underground and a magnetic sensor detects a magnetic field generated by the electric wire as self-position detection for autonomous traveling. Although it has been proposed, if the autonomous driving area is large, such as an autonomous vehicle that performs unmanned grass cutting, lawn cutting, etc. in various fields such as golf courses, river banks, parks, etc. It is difficult to embed the electric wire, and the installation cost becomes large.

For this reason, a technique has been developed in which a plurality of signs are installed in the vicinity of an autonomously traveling area and the position of the vehicle is detected by recognizing the signs.
In Japanese Patent No. 5606, a plurality of retroreflective poles (light reflective markers) standing upright in a specific area are projected, the reflected light is received by an optical sensor, and an angle facing adjacent reflective poles is detected and detected. There is disclosed a technique for detecting the self-position by the three-point angle method (triangulation method) from the angle thus obtained and the known coordinates of the sign.

[0004]

However, in an autonomously traveling work vehicle, since the vehicle tilts or vibrates due to autonomous traveling in a work area with uneven terrain or swell,
The projected light beam may leave the sign or it may be difficult to receive the reflected light from the sign, and the sign may be lost and the self position may not be detected.

The present invention has been made in view of the above circumstances, and it is possible to surely recognize a sign without being influenced by the inclination of the vehicle or the vibration of the vehicle in an area having uneven terrain or undulation, and it is possible to perform accurate measurement. It is an object of the present invention to provide a self-position detection method for an autonomous traveling work vehicle that can detect the self-position.

[0006]

SUMMARY OF THE INVENTION The present invention provides a self-position detecting method for a self-propelled work vehicle, which recognizes a plurality of markers installed around a specific work area and detects the self-position by triangulation. The work vehicle is provided with a rotation mechanism section for rotating the image pickup means so that the entire circumference can be picked up, and the image pickup means sets the time interval at a time interval set based on the rotation speed of the rotation mechanism section and the image pickup angle of view of the image pickup means. It is characterized in that an image of a surrounding area including a sign is picked up, the feature amount of the sign is obtained from a plurality of picked-up images, and the sign is recognized.

[0007]

According to the present invention, the image pickup means is rotated through the rotation mechanism provided in the autonomous traveling work vehicle, and the surrounding image including the mark is set at every time interval set by the rotation speed and the image pickup angle of view of the image pickup means. Image. Then, the feature amount of the sign is obtained from the plurality of captured images, the sign is recognized, and the self-position is detected by triangulation.

[0008]

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 flow chart of a self-position detection routine, FIG. 2 is a flow chart of a main control routine, FIG. 3 is a schematic explanatory view showing the appearance of a lawnmower, and FIG. 4 is a control system. FIG. 5 is a block diagram, FIG. 5 is a circuit configuration diagram of a vehicle position detection unit, FIG. 6 is an explanatory diagram showing a travel route and a work area, and FIG. 7 is an explanatory diagram of self-position detection by triangulation.

In FIG. 3, reference numeral 1 designates an autonomous traveling work vehicle which is capable of autonomous driving by an unmanned vehicle, and in this 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, there is 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.

As the copying traveling sensor, for example, a sled plate which moves up and down according to the length of grass / turf and a rotary encoder which detects a rotation angle of a member supporting 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.

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. 4, and the 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 unit for processing the signals of the sensors and actuators, a vehicle position detection unit 31, a cut boundary detection unit 35, and an obstacle detection unit 36 are provided, and the detection units 31, 35 are used. , 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 the 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, the CCD camera 8a and the light 8b of the image pickup unit 8, and the rotation mechanism unit 10 by accumulating the accumulated data. A sign image pickup controller 33 that outputs each drive signal for sign image pickup to a rotation driving motor 11 such as a built-in step motor or servo motor, and a plurality of video signals from the CCD camera 8a are processed to process a plurality of signals. Recognizing the sign, the rotation angle signal from the rotation angle sensor 12 attached to the rotation mechanism unit 10, and the measurement from the dead reckoning position detection unit 32. A triangulation position detection unit 34 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. It consists of 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 obstacles which cannot be predicted by the non-contact type sensors 5a and 5b and the contact type sensors 6a and 6b, and outputs a detection signal to the traveling control section 37.

The traveling control unit 37 accumulates 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 driven by the drive control unit 40, the steering control unit 41, the 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. 5 shows a concrete circuit configuration of the vehicle position detecting section 31. The CPU 50 has a RAM 51 for holding work data, and a position of a mark 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, controls the image pickup by the CCD camera 8a, processes the imaged image stored in the video memory 65, and recognizes the sign.・ The vehicle position is detected by triangulation.

That is, the CPU 50 executes the program of the self-position detection routine of FIG. 1 which will be described later, and outputs a control signal from the I / O interface 53 to the motor drive circuit 56 and the light drive circuit 57 to turn on the light 8b. The rotation mechanism unit 10 is driven by the rotation driving motor 11 to rotate the light 8b and the CCD camera 8a,
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 picked up by the CCD camera 8a is NT
An SC video signal is sent to the amplifier 58, 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, and the image data is processed to make the work area. 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. 6, reference numerals PA, PB, PC
Is a sign installed in advance around the work area 72.

FIG. 2 is a main control routine executed by the traveling control unit 37. In this main control routine, first, in step S101, the own vehicle position detection unit 31 executes the self-position detection routine of FIG. And labeled PA, PB, PC
Is recognized and the self position is measured by triangulation, the grass
It is confirmed that the lawn mowing vehicle 1 has reached the starting point 74 of the lawn mowing operation, and in step S102, the cutting blade control hydraulic control valve 1
6 is opened to supply hydraulic pressure to the cutting blade mechanism section 2 to operate the cutting blade to start grass / 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 detection unit 31 again executes the vehicle position detection routine, and the vehicle position and traveling direction of the vehicle are determined by triangulation and dead reckoning. After detecting
In subsequent step S105, the work data storage unit 38 is referred to, and the amount of error from the current position is determined with the end point position of the first time (first column) in the work area 72 as the target position.

Next, when proceeding 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 lawn mowing 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 of 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.

Thereafter, the process proceeds to step S114, where the vehicle position detecting section 31 executes the vehicle position detecting routine to detect the vehicle position and traveling direction of the vehicle by triangulation and dead reckoning. It is checked whether 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 flow returns from step S115 to step S110 described above to continue the contour travel along the cut boundary, and to reach 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 completed, 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 completed, this main control routine Stop grass and lawn mowing work by and stop the vehicle.

Next, self-position detection by sign recognition / triangulation by the self-position detection routine of FIG. 1 will be described.

This self-position detecting routine is a routine of the own-vehicle position detecting section 31 started by the main control routine of the traveling control section 37 described above.
Then, when the illumination light 8b is turned on via the light driving circuit 57, the motor 11 is driven via the motor driving circuit 56.
Is driven to rotate the imaging unit 8 (the light 8b and the CCD camera 8a) at a set speed via the rotation mechanism section 10.

Next, in step S202, an imaging time interval in which a blind spot is not obtained is obtained from the rotation speed of the CCD camera 8a and the lateral viewing angle of the CCD camera 8a. The electronic shutter of the CCD camera 8a is calculated for each imaging time interval. To capture images of the surrounding landscape over the entire circumference, and 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 to 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 imaged image data is read, the feature amount corresponding to the imaged sign is obtained from the brightness information and color information of the read imaged image, the shape, etc., and the sign is detected.

That is, each of the markers PA, PB, and PC is used as a light-reflective marker in which a retroreflector is attached over a predetermined length, for example, to increase the brightness of the imaged portion of the marker and binarize the image 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,
The sign can be reliably detected without losing the sign due to the inclination of the vehicle or the vibration of the vehicle itself in the work area with uneven terrain or undulations.

Next, in step S2O4, the center of gravity on the image of the recognized sign and the image of each image of the lawnmower 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. 7, in the X, Y coordinate system with 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 advance in the ROM 52. 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)

[0046]

As described above, according to the present invention, the image pickup means is rotated through the rotation mechanism portion provided in the autonomous traveling work vehicle, and the time set from the rotation speed and the image pickup angle of view of the image pickup means. The image of the surrounding area including the sign is taken at every interval, and the sign is recognized from the multiple images taken to recognize the sign, so the vehicle tilts or the vehicle itself vibrates in areas with uneven terrain or swells. The effect of can be eliminated and the marker can be surely recognized, and an excellent effect such as accurate detection of the self-position can be obtained.

[Brief description of drawings]

FIG. 1 is a flowchart of a self-position detection routine.

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

FIG. 3 is a schematic explanatory view showing the appearance of a lawnmower work vehicle.

FIG. 4 is a block diagram of a control system

FIG. 5 is a circuit configuration diagram of a vehicle position detection unit.

FIG. 6 is an explanatory diagram showing a travel route and a work area.

FIG. 7 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) 10 Rotation mechanism part PA, PB, PC Sign

Claims (1)

[Claims] 1. A self-position detecting method for an autonomous traveling work vehicle, which recognizes a plurality of markers installed around a specific work area and detects the self-position by triangulation, wherein the autonomous traveling work vehicle captures an image of the entire circumference. A rotation mechanism section (10) for rotating the image pickup means (8a) is provided as much as possible, and the rotation mechanism section (10) is rotated at a set time interval from the rotation speed of the rotation mechanism section (10) and the image pickup angle of view of the image pickup section (8a). Self-position detection of an autonomous traveling vehicle characterized by taking an image of the surroundings including the sign by the imaging means (8a) and recognizing the sign by obtaining the feature amount of the sign from the plurality of taken images Method.