JP2594098B2 - Automatic steering device for transplanter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention uses a row of planted seedlings as a guide,
The present invention relates to an automatic steering device of a transplanter that automatically steers a transplanter.

(Prior art)

The rice transplanter includes a traveling body and a planting portion connected to a rear portion of the body, and while the traveling body is running, a seedling mounted on the planting portion is provided with a planting claw mounted on the planting portion. By the above operation, the plant is planted on the rice field at a predetermined interval.

By the way, if the planting interval between seedlings is too narrow,
There is a risk of causing poor growth of the seedlings. Conversely, if the planting interval is too wide, the yield per unit area will decrease, so it is desirable that planting of the seedlings be performed at appropriate planting intervals . In the rice transplanter, the planting claw operates in synchronization with the traveling speed of the traveling machine, and the planting interval in the traveling direction of the traveling machine is automatically adjusted to the appropriate value regardless of the traveling speed. However, in order to keep the planting interval in the direction perpendicular to the traveling direction of the traveling body (hereinafter referred to as the "strain interval") at the appropriate value, the traveling body is moved along the rows of the already planted seedlings. It is necessary to make planting while steering. Therefore, there is a rice transplanter equipped with an automatic steering device that automatically steers the traveling machine body along the rows of the seedlings so that the planting operation can be performed with the interval between the rows kept at the appropriate value.

As an example of the automatic steering device, there is an invention disclosed in JP-A-53-127113. This involves irradiating infrared rays to the rows of the already planted seedlings adjacent to the current planting strips, and reflecting light from the previously planted seedlings by a sensor comprising a plurality of light receiving elements arranged side by side on the side of the traveling body. When receiving light,
By utilizing the fact that the sensor positioned directly above the row of the sensors receives the reflected light, a steering control is performed so that a predetermined sensor always receives the light. The relative position of the traveling body with respect to the rows of the seedlings is maintained at an appropriate position, and when light is received by a sensor located on the left side (or right side) of the predetermined sensor, the relative position of the traveling body is shifted to the right. It is determined that the vehicle is deviated to the left (or left), and a required amount of steering is performed leftward (or rightward) in order to eliminate the deviation.

However, in the invention, since the time-series detected values of the reflected waves from the rows of the infrared seedlings are used for steering control, if the rows of the seedlings are slightly irregular, Unnecessary operation is commanded to the front wheel steering device, the movement shows hunting behavior, and the planted seedling becomes irregular,
In addition, there is a possibility that infrared rays emitted from the sensor may deviate from the rows of the seedlings. In order to solve this problem, there has been disclosed an automatic steering apparatus using a video camera or the like which two-dimensionally captures the image of the seedlings (Japanese Patent Application Laid-Open No. 62-61509). The invention disclosed in the above publication captures a row of seedlings using a video camera, calculates the color difference between the green component and the blue component of the image information, and calculates the image information of the color difference based on a set threshold. For each binarized pixel coordinate, a line segment passing through the binarized pixel is defined as a Hough value expressed in a polar coordinate system and its angle, and the frequency of taking the same Hough value is coefficientd. A line segment is specified from the Huff value and its angle, and the line segment is regarded as a seedling row.

[Problems to be solved by the invention]

However, in the invention, the angle is an angle formed by a reference line and a line segment provided in the traveling direction of the fuselage, and the Hough value is a horizontal distance between a predetermined position of the reference line and the line segment. When the line segment intersects with the reference line with a large inclination in front of the predetermined position, steering information in a direction different from the Huff value and the angle is obtained. For example,
If the line segment is inclined to the left and intersects the reference line, the Huff value is information for steering to the right and the angle is information for steering to the left, so that the priority order cannot be read. Therefore, it is difficult to make both the values close to 0 at the same time by steering only the front wheels, and four-wheel steering is required as in the above-described invention.

In addition, since the Hough value increases as the angle increases, there is a possibility that the follow-up to the seedling row may become poor when the angle increases.

The present invention has been made in view of such circumstances, and by obtaining a Huff value so that the priority order between the Huff value and the angle thereof can be read, the traveling direction of the traveling body is greatly inclined with respect to the reference seedling row. Even if it is, read the steering information by priority and improve the follow-up to the seedling row,
An object of the present invention is to provide an accurate automatic steering device by steering control of only front wheel steering.

[Means for solving the problem]

An automatic steering apparatus for a transplanting machine according to the present invention is an automatic steering apparatus for a transplanting machine that automatically steers according to the rows of planted seedlings. When,
A binarizing means for extracting an image taken by the seedling array imaging device, a means for linearly approximating the binarized pixel, and setting the line segment obtained by the means and the direction of travel of the body in the image Means for calculating an angle between the reference line and a reference point provided on the reference line and a component in a direction orthogonal to a traveling direction of a distance between the line segment, and using the angle and the component as steering information. Means for automatic steering.

[Action]

In the present invention, the Huff value is obtained as a component in a direction orthogonal to the traveling direction of the shortest distance between the reference point and the line segment of the seedling row, and the Huff value is small when the angle between the reference line and the line segment is large. Therefore, in this case, automatic steering is performed with priority given to the angle between the line segment and the reference line.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. FIG. 1 is a side view of a riding rice transplanter equipped with a rice transplanter automatic steering apparatus (hereinafter, referred to as the present invention apparatus) according to the present invention, and FIG. 2 is a plan view thereof.

In the drawing, A is a traveling body supported by a pair of left and right front wheels 1,1 and rear wheels 2,2, and the traveling body A transmits power generated by a power unit 3 mounted on a front part thereof. The power is transmitted to the rear wheel 2.2 through a transmission mechanism such as a main clutch and a transmission (not shown), and the rear wheel 2, 2 rotates to run on the rice field surface.

B is attached to the rear end of the three-point link mechanism 4 attached to the rear part of the traveling body A so as to be able to move up and down with respect to the traveling body A as the mechanism 4 moves up and down. In the case of a six-row rice transplanter, the planting portion B is the second planting portion.
As shown in the figure, a pair of planting claws 7,
7, three sets of seedling plants 6, 6, 6 arranged side by side at an appropriate distance in the left-right direction, and slidably mounted in the left-right direction on the upper side of the seedling plants 6, 6, 6 Seedling platform 8 and seedling planting equipment
Three floats 9,9,9, which are attached to the lower side of 6,6,6 so as to be able to oscillate in the front-rear direction, separated by an appropriate length in the left-right direction
And so on. Thus, the planting section B, which has been lowered on the rice field by the operation of the three-point link mechanism 4, is pulled by the traveling machine A, and slides on the rice field by the action of the floats 9, 9, 9 while planting the seedlings. By the operation of the planting claws 7, 7,... Of the devices 6, 6, 6, ..., the seedling mat placed on the seedling mounting table 8 and sliding down along the seedling mounting table 8 The plants are cut into individual seedlings and planted in rows on the rice field.

On both left and right sides of the traveling body A, slightly forward of the center of the front wheels 1, 1, base end portions of a pair of marker mounting rods 10a, 10a are rotatably mounted in a horizontal plane. 10a, 10a
Markers 10, 10 formed of yellow plastic in a cylindrical shape are attached to the tips bent downward toward the lower side of the rice pad with a suitable distance above the rice field surface. ing. Marker mounting rods 10a, 10a
As shown in FIG. 1 and FIG. 2, it is possible to selectively restrain at one of a position protruding leftward or rightward and a position stored at the lower part of the traveling body A. Yes, when the left (or right) mounting rod 10a is in the protruding position, by matching the marker 10 at the tip with the row of the planted seedling on the left (or right) of the traveling machine A,
The interval between the seedlings planted by the planting section B and the rows of the already planted seedlings can be kept at a predetermined value.

Further, sensor mounting rods 21L, 21R are fixed to the left and right sides of the traveling body A slightly forward and upper than the upper ends of the rear wheels 2, 2, and sensor mounting rods 21L, 21R are fixed. Seedling imaging devices 20L, 20R are attached to the distal ends of 21L, 21R. FIG. 3 is an enlarged side view showing an attached state of the seedling row imaging device 20L,
FIG. 4 is a plan view thereof.

The seedling row imaging device 20L is planted in a front stroke on a rice field a predetermined distance before and downward from the mounting position by using the color video camera 20La with the center of the lens portion directed forward and downward with respect to the traveling direction of the traveling machine. The mounting angle in the front-rear direction is set so that about four outermost seedlings in the seedling row can be imaged, and an image picked up in the field of view is transmitted to an image processing unit 22 described later.

The seedling row imaging device 20R located on the right side of the traveling machine A is attached similarly to the left seedling row imaging device 20L.

A driver's seat DS is provided at the rear of the traveling body A, and on the left side of the driver's seat DS, a main shift lever 11 for changing a gear position of the transmission and disengaging the main clutch, On the right side of the driver's seat DS, work selection levers 12 are provided, respectively.

FIG. 5 is an enlarged plan view of the work selection lever 12 near the mounting position from above. The work selection lever 12 has a lower portion pivotally supported at an appropriate position on the traveling body A, and a guide hole 14 formed in a guide plate 13 fixed on the upper portion of the traveling body A with the longitudinal direction being the longitudinal direction. The middle part is inserted, and it is rotated along the hole 14 in the front-rear direction or the left-right direction and locked at a predetermined locking position, so that various working states can be selected. It was made.

That is, the lever 12 is rotated in the front-rear direction in the rear half portion (the right half portion in FIG. 5) of the guide hole 14 so that the three-point link mechanism 4 is moved to the lifting hydraulic cylinder (not shown). The direction of pressurized oil supply is switched, and the operation of the cylinder raises or lowers the planting portion B with respect to the traveling body A, and locks the locking portion 14a which is formed to branch rightward in the middle of the rear half. By doing so, the planting section B stops at an appropriate height position. By rotating the work selection lever 12 to the front half of the guide hole 14, a planting clutch (not shown) is engaged, power from the power unit 3 is transmitted, and the planting unit B performs its operation. When the lever 12 is locked at the forefront of the guide hole 14, the operating speed of the planting portion B becomes high, and the lever 12 is locked at a middle portion of the front half of the guide hole 14. In this case, the operating speed of the planting section B becomes low. Further, at each of the two locking positions, the work selection lever 12 is rotated right or left along the horizontal holes 14b and 14c branched from the left and right of the guide hole 14, thereby turning the work selection lever 12 rightward or leftward. At the same time as the left marker 10 is projected, the opposite marker 10 is stored.

 FIG. 6 is a schematic plan view of a steering mechanism for the front wheels 1, 1. FIG.

In the figure, reference numeral 30 denotes a front axle horizontally fixed to the lower part of the traveling body A with its longitudinal direction being the left-right direction. Left and right front wheels 1, 1 are provided at both left and right ends of the front axle 30. The knuckle arms 32, 32, which are respectively supported, are rotatably supported on a horizontal plane via king pins 31, 31, respectively. At an appropriate position on the upper surface of the front axle 30, a pivot 33 is provided so as to face upward. A pivot member 34 having a deformed T-shaped planar shape as shown in FIG. , And a T-shaped crossing portion is pivotally supported in a horizontal plane. A portion corresponding to the T-shaped vertical line of the rotating member 34 is projected forward, and its end is connected to the front ends of the knuckle arms 32, 32 through separate link members 35, 36. Each is connected. A right-hand end of a portion corresponding to the T-shaped horizontal line of the turning member 34 is a steering cylinder having its base end pivotally supported on the front of the traveling body A so as to be rotatable in a horizontal plane. An end of the piston rod 40a and an end on the left side thereof are engaged with one end of a spool 41a of a direction switching valve 41 for switching a direction in which hydraulic oil is supplied to the steering cylinder 40, respectively. The direction switching valve 41 is a four-port, three-position switching type, and responds to turning of the front wheel steering handle 15 disposed in front of the driver's seat DS to the left or right. The spool 41a rotates in the vertical plane, and the lower portion thereof is disposed at the lower end of the rotating arm 16 which moves backward or forward by locking the other end of the spool 41a.

The hydraulic circuit of the device of the present invention includes the steering cylinder 40, the direction switching valve 41, a hydraulic pump P that rotates by receiving a driving force from the power unit 3, and a four-port three-position switching electromagnetic direction switching valve V. The pressure oil from the hydraulic pump P is branched in two directions by a distribution valve 42, one of which passes through a direction switching valve 41 and the other passes through an electromagnetic direction switching valve V, and is provided with a steering cylinder 40, respectively. To be sent to

As described above, the spool 41a of the direction switching valve 41 is locked at the lower end of the rotating arm 16, the handle 15 is rotated rightward, and the rotating arm 16 is turned clockwise in FIG. When rotated, the spool 41a is pressed by the lower end of the arm 16, and the pressure oil that has passed through the direction switching valve 41 is supplied to the advance side oil chamber of the steering cylinder 40, and the piston rod
As a result of the advance of 40a, the rotating member 34 rotates clockwise in FIG. 6, and the knuckle arms 32 and 32 and the front wheel 1 are connected via link members 35 and 36 locked to the front end of the member 34. ,
1 is steered to the right. When the handle 15 is rotated leftward, the pressure oil that has passed through the direction switching valve 41 is supplied to the retreat-side oil chamber of the steering cylinder 40, and the piston rod 40
As a result of a retreat, the steering mechanism operates in the opposite direction to that described above, and the front wheels 1, 1 are steered to the left.

Further, when the solenoid Sl (or the solenoid Sr) of the electromagnetic directional control valve V is excited, the pressure oil from the hydraulic pump P passes through the valve V and enters the retreating side of the steering cylinder 40 (or As a result of the piston rod 40a being retracted (or advanced) by this pressure oil, the handle 15 is rotated leftward (or rightward) in the same manner as described above. The rotating member 34 rotates clockwise (or counterclockwise) in FIG. 6 and the left and right front wheels together with the knuckle arms 32, 32 via link members 35, 36 locked at the front end of the member 34, respectively. 1,1 is steered left (or right).

In order to detect the steering angle of the front wheels 1, 1 thus steered, a steering angle sensor using a potentiometer that outputs a potential according to the rotational position of the king pin 31 to one of the king pins 31, 31. 38 is installed. The steering angle sensor
38 outputs a negative potential when the vehicle is steered to the right with respect to straight ahead, and outputs a positive potential when the vehicle is steered to the left.

When the operating force is not applied to the handle 15, even when the turning position of the turning member 34 is changed by the operation of the hydraulic cylinder 40 due to the pressure oil passing through the electromagnetic direction switching valve V, the direction switching valve 41 is configured to assume its neutral position by the action of a spring provided on the spool 41a, and the handle 15 is thereby returned to the straight running state. At the base end of the steering column 15a connected to the steering wheel 15, a manual steering detection switch 54 (see FIG. 7) which is turned on when the steering wheel 15 is rotated rightward or leftward from a straight running state. It is arranged.

FIG. 7 is a block diagram of a control system which is a gist of the present invention, and FIG. 8 is a block diagram showing a configuration of an image processing unit. 50 in the figure is a steering control unit comprising using a microprocessor, the output of the image processing unit 22 is given to the input port a ₁ of the control unit 50. Image processing unit 22
Uses a microprocessor, and has a resolution of 256 pixels in each of the vertical and horizontal directions. The image processing unit 22 is operated when the work selection lever 12 is rotated leftward or rightward along the horizontal hole 14b or the horizontal hole 14c of the guide hole 14, and the left or right marker 10 is projected. Selector switch 221 for switching and selecting left and right seedling row imaging devices 20L, 20R, separates NTSC video camera input signal into red, green, blue color signals R, G, B for each pixel of this image processing unit The camera input signal converter 222 consisting of an NTSC decoder
Based on the green and blue color signals R, G, and B, a binarization operation unit 225 that binarizes image information by an operation described later, and extracts pixels having a predetermined pixel-to-pixel distance from the binarized pixels And a Huff transform unit 227 that performs linear approximation by the extracted pixels.
25, the pixel extraction unit 226, and the Hough conversion unit 227 perform their operations by the microprocessor. The Huff converter 22
7 and the camera input signal converter 222 are connected to the monitor output signal converter 223 which converts various information such as image information calculation results and linear approximation results into video signal outputs, and displays the various information by the converted video signals. Color monitor 224
Are connected to the monitor output signal converter 223. The output from the Hough converter 227 is the input port a of the steering controller 50.
It is given to the _1.

Also the input port a ₂ of the steering control unit 50, the output potential of the steering angle sensor 38 and is supplied, the signal input to the input port a _2, at the input interface of the steering control unit 50 The CPU of the steering control unit 50 performs predetermined processing and outputs digital data D corresponding to the current steering angle of the front wheels 1 and 1.
Is to be taken into.

Also the input port a ₃ of the steering control unit 50 is disposed in the manually operable position by an operator seated on the driver's seat DS, when to perform automatic steering, connection an automatic switch 51 to be turned on It is, when the switch 51 is turned on, the input port a ₃ turns to the high level.

The input port a ₄ is connected to a planting switch 52 that is turned on when the work selection lever 12 is at the rotation position of the front half of the guide hole 14, and the steering control unit 50 is turned on when the switch 52 is turned on. input port a ₄ Te is by a high level, recognizes that the planting unit B is operating.

The input port a _5, the main clutch switch 53 which is turned on when the main clutch is engaged by the operation of the main speed change lever 11
There are connected, the steering control unit 50 recognizes that the input port a ₅ with the ON of the switch 53 by a high level, the traveling machine body A is traveling.

Further the input port a ₆ of the steering control unit 50 is connected to the manual operation detection switch 54 which is arranged as described above, when the switch 54 is turned on the input port a ₆ turns to the high level It is done.

On the other hand, the output port b ₁ of the steering control unit 50 is connected to a switching transistor 60 interposed between the solenoid Sl of the electromagnetic directional control valve V and the body ground.
Output port b ₂ is connected to the switching transistor 61 interposed between the solenoid Sr and body earth. When the output port b ₁ (or the output port b ₂ ) becomes high level, the switching transistor 60
(Or 61) operates, and an exciting current flows through the solenoid Sl (or Sr).

Output port b ₃ of the steering control unit 50, automatic lamp 62 for allowing informing the operator that the steering control is performed
To, and the output port b _4, the seedling rows imaging apparatus 20L, already Uenae by either 20R has been detected, seedlings detection for allowing informing the operator that the steering control is properly performed The output ports b ₃ and b ₄ are connected to the lamps 63, respectively.
Each lamp is turned on according to the high-level output of.

The output ports b ₅ and b ₆ are connected to an alarm lamp 64 and an alarm buzzer 65 for various alarm outputs, respectively, and the alarm lamp 64 is turned on according to the high level output of the output port b ₅ ,
So that the alarm buzzer 65 is sounded in response to the high level output of the output port b _6.

Steering control unit 50, seedling row imaging devices 20L, 20R, and solenoid S
l, Sr, together with the steering angle sensor 38 and each switch, are both connected to a power supply via a key switch 70 for starting the engine, and perform respective operations only when the switch 70 is turned on. be able to.

Now, the operation of the steering control unit 50 configured as described above will be described together with the procedure of planting work by a riding rice transplanter equipped with the device of the present invention.

When the automatic switch 51 is turned on by the worker sitting in the driver's seat DS and the input port a ₃ is turned to a high level, the steering control unit 50 intermittently sets the output port b ₃ to the high level, and sets the automatic lamp 62 Blinks to notify the operator that the control operation is in the preparation stage.

Next, the operator rotates the work selection lever 12 forward to lower the planting portion B on the rice field surface, further selects the operation speed of the planting portion B according to the traveling speed of the traveling machine A, and performs the work. The selection lever 12 is rotated to a predetermined locking position in the front half of the guide hole 14. By this lever operation, the planting switch 52
When There input port a ₄ is turned turns to the high level, the steering control unit 50, the output port b ₃ and continuously high level, the automatic lamp 62 is turned on to start the control operation thereafter.

Now, after locking the work selection lever 12 at the predetermined locking position, for example, when the row of the already planted seedlings serving as the copying guide is on the left side of the traveling machine A, the worker selects the lever 12. By rotating to the left, the left marker 10 is projected to the left of the body A.

The worker, while visually recognizing the marker 10 protruding to the left, this is one of the rows of seedlings planted in the previous process,
After operating the handle 15 so as to be located immediately above the rightmost row, the positioning of the traveling machine A is roughly performed. Then, while visually recognizing the seedling detection lamp 63, the handle is operated until the lamp is turned on. By operating 15, the initial position of the traveling body A is set, and thereafter, the seedlings planted at predetermined intervals in the row are continuously imaged by the seedling row imaging device 20L. A predetermined reference position S is obtained by an operation described later of the image processing unit 22 and the steering control unit 50 based on the imaging result.
(In this embodiment, the traveling body A is set so that the seedling is always positioned at the center line of the imaging range of the color video camera 20La).
Is automatically steered.

FIG. 9 is a flowchart showing the control contents of the image processing unit. When a seedling already planted is imaged by the seedling row imaging device 20L, the image processing unit 22 sets a video camera input signal which is image information of the color video camera 20La. At each timing, the captured camera input signal converter 222 separates the color signals R, G, and B into red, green, and blue signals. This process is performed for all the pixels. However, if it is performed for 256 pixels in the vertical and horizontal directions × 256 pixels = 65,536 pixels, a large amount of time is required for the calculation time. Therefore, the processing is performed for 32 pixels in the vertical and horizontal directions × 32 pixels = 1024 pixels. That is, each of the signals R, G, B is sampled every eight pixels.
Are separated (step 1).

Next, the image information is binarized by the binarization operation unit 225 using the following conditional expression based on each color signal R, G, B of each separated pixel,
Pixels based on seedlings are extracted (step 2).

G> R and G> B and G> 0.38 (R + B + G) (1) The above conditional expression (1) was invented in order to binarize the values of each color signal R, G, B without using a threshold value. Yes, this eliminates the need to change the threshold value according to external conditions such as the intensity of disturbance light that changes with time.

Next, means for extracting the obtained binarized image and approximating the straight line will be described. FIG. 10 is a schematic diagram in which a binarized image is displayed in the imaging range, where the center O of the imaging range is the origin, the traveling direction is the y-axis positive direction, and the left-right direction is the x-axis direction. . S indicates the reference position, and in this embodiment, coincides with the y-axis. Further, a to g indicate binarized images, and subscripts of the images a, b,... Indicate respective pixels.

When the images a, b ... are binarized, 32 × 32 from the upper left of FIG.
The pixels are scanned, and pixels α are extracted in order from the top (pixel a _{1 in} FIG. 10). Next, all the extracted pixels α and the pixels β within the following conditions are extracted (step 3).

Assuming that the x and y coordinates of the pixel α are x _α and y _α and the x and y coordinates of the pixel β are x _β and y _β , respectively, the conditional expression is set as follows.

| x _α −x _β | ≦ 4 (2) y _α −y _β ≧ 8 (3) In general, when performing rice transplanting in accordance with an already planted seedling, the inclination of the seedling row of the already planted seedling relative to the traveling direction of the rice transplanter Is small, and the length of the straight line component shown in the image for each seedling is equal to or less than a certain pixel because the length of the seedling is substantially equal to or less than a certain length. From these facts, a pixel having a small inclination is extracted by the conditional expression (2), and the extraction of the same seedling is prevented by the conditional expression (3), and the linear component of the seedling affects the approximate straight line. I try not to.
The conditional expression in this example (2), the pixels b ₁ ~ at (3)
b _5, d ₁ ~d ₄ are extracted, the pixels _{c 1 ~c 4, e 1,} e 2, f 1, f 2, g 1, g
₂ is not extracted. Similarly, the pixel β is extracted using the conditional expressions (2) and (3) for the next pixel α (the pixel a _{2 in} FIG. 10), and this operation is repeated until the pixel β cannot be extracted (step 4). .

Next, the Hough transform unit 227 calculates a straight line connecting the pixel α and the extracted pixel β, and calculates the number of the straight line, the straight line and the center O
Distance between ρ _1, ρ ₂ ... and the angle θ _1, θ ₂ ... a determined (Step 5).

Next, the obtained distances ρ ₁ , ρ ₂ ... And angles θ ₁ , θ ₂
.. Are obtained, and the obtained distance is ρ and the angle is θ. This ρ is the Hough value to be obtained and θ is the angle. Then, the calculation of the Hough value ρ and the angle θ is calculated for each set timing (step 6).

When the image processing unit 22 calculates the Hough value ρ and the angle θ at each set timing, the values are output to the steering control unit 50 (Step 7).

As described above, in the present embodiment, since the image is sampled by 32 pixels to separate the color signals, the calculation speed can be increased, and the binarization is performed without using the threshold value. It is not necessary to perform a setting operation such as changing a threshold value due to light and darkness, and a pixel having a predetermined range of pixel distances among the binarized pixels is extracted and linearly approximated. Pixels other than seedlings such as noise are not affected by the linear approximation.

In the automatic steering control using the normal Hough value, the Hough value ρ and the angle θ on the obtained image are replaced with the Hough value ρ ₀ and the angle θ on the field surface.
₀ (see FIG. 4), and the target steering angle obtained thereby is compared with the digital data D obtained by the steering angle sensor 38 to perform the steering control. Since a large amount of calculation is required to convert the Hough value on the surface, in the present embodiment, a steering instruction amount corresponding to the value of the Hough value ρ and the value of the angle θ is separately set, and automatic steering is performed based thereon. .

Table 1 shows an example of the relationship between the distance ρ and the distance steering instruction amount S _ρ corresponding thereto, and Table 2 shows an example of the relationship between the angle θ and the angle steering instruction amount S _θ corresponding thereto. It is shown.

Determining an actual steering command amount S obtains an average of the distance steering command amount S _[rho and angle steering command amount S _theta obtained.

Next, the above will be described in comparison between the embodiment and the conventional example.

FIG. 11 is a graph showing an example of the Hough value of the embodiment of the present invention and the Hough value of the conventional example, in which the vertical axis indicates the traveling direction, the horizontal axis indicates the left-right direction, and the solid line indicates a straight line approximation. A row of seedlings is shown.

Conventional Hough value [rho 'of the relationship between the Hough value [rho of Example ^{ρ = ρ'cos 2 θ ... (5} ) next, in the Figure 11 [rho' shows the case of a = 8, θ = 30 ° ,in this case Becomes

Next, distances and angle steering instruction amounts S _ρ , S _{ρ ′} , S _θ corresponding to the respective Hough values ρ, ρ ′ and the angle _θ are obtained, and the actual steering instruction amounts S, S ′ of the embodiment and the conventional example are obtained. And ask for Equation (7) is obtained. As is clear from the equation (7), the conventional example has poorer follow-up with respect to the line segment of the seedling row as compared with the embodiment.

That is, in the conventional example, as the angle θ increases, the Hough value ρ ′
Is larger, but in the embodiment, as the angle θ becomes larger,
The Hough value ρ decreases.

Therefore, in the present invention, when the angle θ is large, the value of the angle θ mainly affects the actual steering instruction amount S, but in the conventional example, the angle θ and the Hough value ρ are equal to the actual steering instruction amount S ′. Affect.

Compared then obtained between the actual steering command amount S and the digital data D, the difference U (U = S-D) high level to the output port b ₁ or b ₂ of the steering control unit 50 in accordance with the Give the output,
The solenoid Sl or Sr is excited to perform automatic steering. When the actual steering instruction amount S is positive, the steering is set to the left, and when the actual steering instruction amount S is negative, the steering is set to the right. When steering to the left, the output port b ₁ (or b ₂ ) is output at a high level when the difference U is positive (or negative), and the solenoid Sl (or Sr) is turned on. Excited, the traveling body A is steered to the left (or right). This automatic steering control is performed at each set timing.

As described above, in the present embodiment, the binarization operation unit 226
Since pixels having a predetermined distance from the binarized pixels are extracted and subjected to the Hough transform, highly accurate linear approximation can be performed without being affected by the linear components of the seedlings, the pixels due to noise, and the like. In addition, since the Hough value ρ is obtained as the left-right component of the shortest distance between the line segment of the seedling row and the reference point O, even if the angle θ increases, the following of the seedling row can be performed with high accuracy.

On the other hand, when the binarization operation unit 225 cannot perform binarization, or when the pixel extraction unit 226 cannot extract pixels,
Steering control unit 50, together with the immediately stops its control operation, the output port b _5, b ₆ to the high level, the alarm lamp 6
4 is turned on, and the alarm buzzer 65 is sounded to notify the operator that automatic steering is impossible.

Also, the steering control unit 50 constantly monitors the level of the input port a ₆ while performing the control operation as described above,
If the input port a ₆ is turned to a high level, it is determined that manual operation of the handle 15 is made by the operator, in order to give priority to steering by this operation, immediately stop the steering control operation. And this stop, the operation of the handle 15 is completed, the input port a ₆ is released from and returns to the low level after a predetermined time elapses, Hereafter, steering control unit 50 continues the above control operation Do.

In the present embodiment, a color video camera is used as a seedling row imaging device. However, the present invention is not limited to this, and any imaging device capable of detecting a seedling and binarizing it can be used.

In this embodiment, the reference position is set as the center line in the traveling direction of the imaging range, and the Hough value and its angle are obtained from the center point of the imaging range. However, the present invention is not limited to this. And the point for obtaining the Hough value and the angle may be anywhere in the imaging range.

〔effect〕

As described above in detail, in the apparatus of the present invention, the calculation of the Huff value is performed based on the left-right direction component of the distance between the line segment indicating the seedling row and the reference point. Even if the angle made by does not increase, the Huff value does not increase, and the priority order between the Huff value and the angle can be clearly read,
Excellent effects are obtained, such as improved follow-up of the row of seedlings and accurate automatic steering by steering control of only the front wheel steering.

[Brief description of the drawings]

1 is a side view of a riding rice transplanter equipped with the apparatus of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is an enlarged side view of a seedling row imaging device, FIG. 4 is a plan view thereof, and FIG. FIG. 6 is a schematic plan view of a front wheel steering mechanism, FIG. 7 is a block diagram showing a configuration of the apparatus of the present invention, and FIG. 8 is a configuration of an image processing unit. FIG.
FIG. 14 is a flowchart showing control contents of the image processing unit, and FIG.
The figure is a schematic diagram showing a binarized image within the imaging range, and FIG.
FIG. 5 is a graph showing the Hough value of the embodiment of the present invention and the Hough value of the conventional example. A: traveling body, B: planting section, 1 ... front wheel, 2 ... rear wheel, 10 ... marker, 12 ... work selection lever 20L, 20R ... seedling row imaging device, 22 ... image processing section 38 ... steering angle sensor, 50 ... Steering control unit

Claims (1)

(57) [Claims] 1. An automatic steering device for a transplanter that automatically steers according to the rows of planted seedlings, comprising: a seedling imaging apparatus that images the rows of the seedlings; Means for extracting an image picked up by the camera, means for linearly approximating the binarized pixel, and a line segment obtained by the means and a reference line set in the traveling direction of the aircraft in the image. Means for calculating a component formed in a direction orthogonal to the traveling direction of the angle between the line segment and the reference point provided on the reference line, and means for automatically steering using the angle and the component as steering information. An automatic steering device for a transplanter, comprising: