JP2593165B2 - Automatic steering detection device for agricultural work machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an agricultural work machine such as a rice transplanter which is already planted in a field and is arranged in a substantially straight line, so as to be substantially parallel to a so-called planting seedling line. The present invention relates to a structure of a detection device for automatic steering that enables the vehicle to travel.

[Conventional technology and its problems]

Conventionally, when planting seedlings in a field with a rice transplanter, the rice transplanter is provided with planting mechanisms at appropriate intervals on the left and right in the traveling direction, and the seedling mat on the seedling table is rotated by the planting mechanism that rotates up and down as the rice transplanter advances. Are planted in the field scene while dividing them by the number of plants as appropriate, so that in the field scene, at the appropriate seedling planting intervals along the traveling direction of the rice transplanter, It is well known that a plurality of rows are planted at appropriate intervals in a direction.

Japanese Patent Application Laid-Open No. 62-61509 discloses a prior art of a planting seedling detection device for automatic steering that enables a rice transplanter to run in substantially parallel to a planting seedling already planted in a field. Then, a color video camera mounted on the rice transplanter that moves forward captures an appropriate range of the planted seedling row in the adjacent portion, and binarizes the captured screen information to correspond to each planted seedling location. It has been proposed to detect a planted seedling row by approximating a straight line from a row composed of the plurality of areas by performing processing such as Hough transformation after extracting a region.

Then, the steering control of the aircraft is performed so that the deviation of the lateral displacement and the inclination with respect to an arbitrary reference line such as the calculated virtual straight line and the vertical and horizontal center lines of the imaging screen and the reference point fall within a predetermined allowable range. .

In the prior art, a planting seedling row in a single one-time imaging screen obtained by an imaging unit is linearly approximated according to a certain method, and a screen imaged as the aircraft advances. Since the binarization and the approximation calculation are performed again from the beginning at a place where the number of the changed seedlings is calculated, it takes a long calculation time to detect the planted seedling row, and if the speed is to be increased, the computer becomes large. There's a problem.

In addition, since the data from the previous imaging screen is not taken into account in the current data before and after the time, fluctuations in the lateral shift position of the aircraft and changes in the inclination with respect to the traveling direction that change with time in the planting seedling row are considered. There is a problem that the data is not considered as data and the stability of the automatic steering is deteriorated.

In addition, since the management machine for applying fertilizer or spraying the chemical at an appropriate time after the seedling planting work may perform the work while proceeding along the already planted seedling row, the agricultural work machine may be automatically operated. The same problem as described above occurs when a steering device is mounted.

An object of the present invention is to solve this problem.

[Means for solving the problem]

Therefore, the present invention provides an image pickup means for picking up an appropriate number of planted seedling locations in a row of planted seedlings already planted along a side of an agricultural work machine such as a rice transplanter running in a field, and an image of the image pickup means. An image processing apparatus having two planting means for specifying the position of each planted seedling location from the information and calculating means for calculating the binarized coordinates of each planted seedling location is provided. The imaging data is output intermittently, the previous data of the coordinate position of each planted seedling location obtained by binarizing the intermittent image information is compared with the current data, Is obtained.

[Functions and effects of the invention]

According to this configuration, the imaging means mounted on the aircraft in progress images the planted seedling row at appropriate time intervals, and the previous data of the image information is compared with the current data. It is possible to calculate, as information, the direction and the distance moved during the time interval.

In other words, using the data of the image information due to this time difference, the deviation (tilt) in the traveling direction of the aircraft with respect to the planting seedling row
Also, since the distance of the lateral displacement can be calculated and detected, the calculation time for image processing can be greatly reduced as compared with the case where the straight line of the planting seedling row is calculated on one imaging screen.

Therefore, when performing automatic steering control to keep the inclination and lateral displacement of the aircraft with respect to the existing seedling row within a certain allowable range, the automatic steering control of the aircraft is extremely simple simply by using these data based on the time difference. You can do it.

〔Example〕

In the following, an embodiment applied to a rice transplanter will be described. In FIG. 1, reference numeral 1 denotes a traveling body supported by front wheels 3, 3 on the front left and right sides of a frame 2 and rear wheels 4, 4 on the rear left and right sides.
At the rear of the traveling machine 1, a multi-row planting seedling plant 7 composed of a seedling mounting table 5 and a plurality of planting mechanisms 6 is provided with a link mechanism 8.
It is mounted so that it can be moved up and down via

Engine 9 mounted on the upper surface of frame 2 of traveling body 1
Is transmitted to the front and rear wheels 3 and 4 via a clutch 10 and a transmission case 11, while the transmission case 1
Power is transmitted to the seedling plant 7 via a PTO shaft 12 protruding from 1. Reference numeral 13 denotes an actuator for ON / OFF of the clutch 10, 14 denotes an actuator for traveling speed change, and 15 denotes an actuator for PTO shaft speed change.

On the upper surface of the traveling body 1, a steering gear box 17 is provided in front of a control seat 16, and at the upper end of a steering column 18 erected from the steering gear box 17,
Steering shaft inserted into the steering column 18
A steering handle 20 for 19 is installed.

Reference numeral 21 denotes a left and right longitudinal transmission case in which front wheels 2, 2 are mounted via knuckles 22, 22 on both left and right ends and a power transmission mechanism from the transmission case 11 is housed inside.
Is connected via a bracket 21a having a U-shape in plan view to be attached thereto and a swing shaft 21c rotatably supported by a support member 21b at the center of the lower surface of the frame 2 at the left and right. It is configured to be able to.

The steering device 26 has an L-shaped steering arm 24 in a plan view mounted on a rotation fulcrum shaft 23 erected from one side of the transmission case 15 so as to be horizontally rotatable, and a pair of left and right tie rods connected to the steering arm 24. 25, 25, a hydraulic cylinder 26, a steering control valve 27, and a pitman arm capable of swinging back and forth of a steering gear box 7 for operating the steering control valve 27.
Consists of 28.

One end of each of the pair of left and right tie rods 25, 25 is connected to an arm portion 24a of the steering arm 24 extending in the front-rear direction of the frame 4 via a ball joint, and the two tie rods 25, 25 are substantially attached to the transmission case 15. Running aircraft 1 along
The left and right ends of each of the NASX 22 and 2
It is swingably connected to knuckle arms 29, 29 extending forward from 2.

A control valve 27 is provided on a support shaft 30 of an arm portion extending inward from the steering arm 24 toward the side surface of the frame 2.
Is connected backward through a ball joint, while the steering control valve
Link the spool at the rear end of 27 with the pitman arm 28
Connect via 31.

The rear end of a hydraulic cylinder 26 disposed substantially parallel to the outer surface of the frame 2 is connected to the support shaft 30 via a ball joint, while the front end of the piston rod 26a is connected to the frame via a ball joint. 2 Connected to the bracket horizontal shaft 32 projecting from the outer surface.

While the steering control valve 27 and the hydraulic cylinder 26 are each connected by a hydraulic hose, hydraulic pressure is sent from a hydraulic pump 33 driven by the engine 5 to an electromagnetic solenoid type control valve 27.

The spool of the control valve 27 is moved forward and backward by the pitman arm 28 that swings in accordance with the rotation angle of the steering handle 10, and the piston rod in the hydraulic cylinder 26 is moved.
26a is moved in and out, and the directions of the left and right front wheels 2, 2 are changed in accordance with the rotation of the steering arm 24.

The hydraulic cylinder 26 is also controlled by an electromagnetic solenoid type steering control valve 34 operated by an automatic steering / running central control device 35 that outputs an output signal in accordance with a signal from a planting seedling detection device 37 described later. When driven, the steering angle of the front wheel 3 is executed by detecting the turning angle of the steering arm 24 with a potentiometer 36 attached to the turning fulcrum shaft 23.

Incidentally, an actuator 13 for ON / OFF of the clutch 10,
Actuator 14 for traveling speed change, actuator 1 for PTO shaft speed change
5 can also be activated by the central controller 35.

The planting seedling row detection device 37 includes an imaging unit 40 for imaging the target.
And an image processing device 41 for processing a captured image and outputting necessary information (data).

The imaging means 40 can image a detection target like a color video camera and output imaging information of the imaging screen 42 as an electric signal, and can be a two-dimensional MOS imaging device or a two-dimensional CCD.
In the image pickup means 40 having an image pickup element, an image formed through a lens is sensed by each photoelectric element arranged in a two-dimensional array on the image-determining surface and information on the image pickup screen 42 is output as an electric signal. You can do it.

A display element for forming one imaging screen 42 is referred to as a pixel. In other words, each element obtained by dividing one imaging screen into elements having a small area is a pixel. In the two-dimensional image sensor, each image sensor corresponds to one pixel. For example, one screen is sampled by 256 × 256 pixels.

The image processing device 41 outputs data of the imaging screen 42 captured by the imaging unit 40 at appropriate time intervals, binarizes the data at appropriate time intervals, and performs the binarized planting. The position coordinates of the seedlings are calculated, and the change in the position of the planted seedling row is calculated from the comparison between the current coordinate data and the previous coordinate data.

That is, first, the rice transplanter is advanced along the planted seedling row already planted in the field, and a plurality of planted seedling locations (NAEs) of the planted seedling row adjacent to the machine body are appropriately timed by the imaging means 40. Images are taken at intervals (see FIG. 5). The time interval (Δt) at this time is set to such an extent that the same planting seedling portion (NAE) is imaged, assuming that the previous image and the current image are duplicated on the same screen.

And an imaging screen taken out at each of the time intervals (Δt).
The binarization for extracting the seedling locations (NAE) planted from the data of 42 from the mud surface of another field is performed by using the RGB color system [red (R),
Green (G) and blue (B) color lights are used as primary color lights, and white is obtained by adding light.] The characteristics of the field scene are extracted from the signals of the red, green, and blue components. When the ratio of the signal output of the green (G) component to the sum total of the signal outputs of the three color components (R + G + B = 1) is equal to or greater than a predetermined value, the region (A) is determined from other portions 43 of the screen 42. A binarization process for segmentation and specification is executed (see FIG. 6).

In addition, binarization may be executed by a color difference process of judging a portion where the color difference image data (GB) obtained by subtracting the blue component from the green component of the color signal in the image is equal to or more than a predetermined value as a seedling.

Since each of the binarized target areas (A) is specified as a set of a plurality of pixels, the target area (A) is determined from the set of pixels by a predetermined calculation method using software incorporated in the image processing apparatus 41. After reading the coordinates of the center or the position of the center of gravity of the specified target area (A), the following calculation is executed.

That is, in FIG. 7, the vertical axis (Y-axis) is taken in the direction of travel of the aircraft, the horizontal axis (X-axis) is taken in the lateral direction of the aircraft, and the same imaging screen 42 is moved back and forth by a time interval (Δt). Considering each coordinate at the time point plotted, the coordinates of the center of the target area corresponding to each previous planting seedling location are (X
1, Y1) (X2, Y2) (X3, Y3) ...
1 ', Y1') (X2 ', Y2') (X3 ', Y3') ... (Y1 '-Y1) corresponds to the moving distance of the aircraft in the forward direction of the aircraft. At the same time, it is possible to detect the planting interval by the vertical swinging of the planting mechanism 6 based on the distance,
The result of dividing (Y1′−Y1) by the time interval (Δt) can be detected as the forward speed V of the aircraft.

Further, the difference (X1′−X1) in the X-axis direction is the amount (δ) of the lateral displacement of the aircraft during the time interval (Δt) as a result of steering the aircraft.

Further, (Y1′−Y1) ÷ (X1′−X1) = tan θ indicates the degree of inclination of the aircraft during the time interval (Δt).

Then, an image processing apparatus according to the flowchart of FIG.
In the calculation of 41, the slope taθ and the lateral shift (δ) are calculated at appropriate time intervals as described above, and the values of (δ) and tanθ are calculated based on the error of the slope with respect to a reference line along the planting row. It is determined whether or not the error is within an allowable range with respect to the distance in the horizontal direction with respect to the reference line.If the error is out of the allowable range, an output signal is output to the central control unit 35, and the steering control valve 34 is output.
Then, the electromagnetic solenoid is operated to drive the hydraulic cylinder 26 that changes the rotation angle of the steering arm 24 in the steering mechanism to perform corrective steering, and execute automatic steering control so as to fall within a predetermined error tolerance. In this case, it is determined whether or not the front wheel 3 has a steering angle that inclines rightward or leftward with respect to the traveling direction by a potentiometer 36 that detects the rotation angle of the steering arm 24. It can be used for convergence control that progresses in parallel with the row of seedlings.

If it is within the allowable range, the control of the automatic steering is maintained as it is.

Note that a reference line KO such as the central vertical axis of the imaging screen 42 can be used as a reference for the inclination.

Further, the difference between the coordinates of the current planted seedling location (NAE) and the previous coordinates at each time interval (Δt) is calculated for each of the plurality of planted seedling locations (NAE), and the difference between the plurality of coordinates is calculated. If the average value of the data is used to calculate the inclination and lateral deviation errors of the planted seedling row, the influence of the variation on the reference line (virtual line) of each planted seedling location can be reduced.

[Brief description of the drawings]

1 is a plan view of a riding type rice transplanter, FIG. 2 is a side view, FIG. 3 is a plan view of a main part of a steering device, and FIG. 4 is steering and traveling. FIG. 5 is a block diagram of an automatic control device and an operation explanatory diagram including a hydraulic circuit, FIG.
FIG. 7 is a diagram of a binarized imaging screen, FIG. 7 is an explanatory diagram of the binarized imaging screen, and FIG. 8 is a schematic flowchart. 1 ... traveling body, 2 ... frame, 3,4 ... wheels, 5 ...
… Seedling stand, 6… Planting mechanism, 7… Seedling plant, 8… Link mechanism, 9… Engine, 11… Mission case,
17 ... steering gear box, 20 ... steering handle, NAE ... planting seedling location, K ... virtual line, 23 ... rotating fulcrum shaft, 24 ... steering arm, 26 ... hydraulic cylinder, 34 ... steering Control valve, 35 Central control device, 36 Potentiometer, 40 Image pickup means, 41 Image processing device, 42 Image pickup screen, A area.

Claims (1)

(57) [Claims] An image pickup means for picking up an appropriate number of planted seedling locations in a row of planted seedlings already planted along a side of an agricultural work machine such as a rice transplanter running in a field, and an image of the image pickup means. An image processing apparatus having two planting means for specifying the position of each planted seedling location from the information and calculating means for calculating the binarized coordinates of each planted seedling location is provided. The imaging data is output intermittently, the previous data of the coordinate position of each planted seedling location obtained by binarizing the intermittent image information is compared with the current data, An automatic steering detection device for an agricultural work machine, characterized by obtaining movement information of a vehicle.