JPH0257107A - Automatic steering control apparatus of farm working machine - Google Patents

Abstract

PURPOSE:To perform smooth operation of the subject machine by outputting a steering output signal to a steering driving means through a specific controlling amount output means according to the indicated steering amount calculated based on the signal transmitted from a crop row-detection means. CONSTITUTION:A crop row is detected by a detection means such as an image- pickup means 34, a steering indication amount is determined by an indication amount determination means and a steering output signal is outputted from a control amount output means to a steering driving means at intervals within a specific range. In the former time zone in the signal output cycle time, a 1st preset steering output signal corresponding to the indicated steering amount is retained for a prescribed period and, thereafter, a 2nd preset steering output signal to correct the direction toward the neutral steering position is outputted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a method that allows an agricultural machine such as a rice cultivation machine to run substantially parallel to so-called rows of crops that have already been planted in a field and lined up in rows. The present invention relates to the structure of an automatic steering control device.

[Conventional technology]

Conventionally, when planting seedlings in a field using a rice transplanter, for example, the rice transplanter is equipped with planting mechanisms at appropriate intervals on the left and right in the direction of movement.
The planting mechanism, which moves up and down as the rice transplanter advances, divides the seedling mat on the seedling platform into appropriate numbers of plants and plants them on the field, so the rice seedlings are placed on the field in an appropriate manner along the direction of movement of the rice transplanter. It is well known that the seedling planting intervals are such that the seedling locations are lined up and at the same time, the seedlings are planted in multiple rows at appropriate intervals in the left and right directions with respect to the direction of travel.

As a prior art for an automatic steering device that allows a rice transplanter to run approximately parallel to rows of planted seedlings (hereinafter referred to as crop rows) that have already been planted in the field, Japanese Patent Laid-Open No. 62-61509
In the publication, a color video camera mounted on a rice transplanter that moves forward images an appropriate range of the adjacent crop rows, and this image information is binarized and each planting is carried out at the crop location. After extracting the corresponding region, Hau
gIt) Approximately calculate a straight line from the row made up of the plurality of regions by processing such as conversion, and calculate the horizontal and inclination deviations between this calculated virtual straight line and arbitrary reference lines and reference points such as the vertical and horizontal center lines of the imaging screen. It is proposed that the steering control of the aircraft be executed so that the deviation, such as the gap between

[Problem to be solved by the invention]

By the way, in a so-called manual steering operation by a normal worker, for example, when the crop row is biased toward the far side from the side, the steering wheel is turned in the direction to bring the crop closer to the side within a predetermined deviation, and the steering wheel is turned in the direction to bring the crop closer to the side within the predetermined deviation. It is normal to perform an operation to return the steering wheel to the opposite side, that is, the steering wheel, to the neutral position. ) and its speed, as well as the speed at which the steering wheel is returned to the neutral position after turning the steering wheel, are adjusted by human senses to achieve smooth steering.

However, in automatic steering control, if there is a difference between a detected value, which is a deviation detected by an imaging means, etc., including the prior art, and a target value, an output signal (operated amount) is sent to the steering drive means (for example, a hydraulic cylinder). Assuming that the control operation that produces the output is performed discontinuously, there is a so-called two-position operation (ON/OFF) in which the manipulated variable takes an appropriate fixed value and turns that value ON/OFF.
・It is known that it is good to execute OFF control).
When using this control, although the control structure is extremely simple, the steering angle is suddenly changed to a specific value, and after holding that value for a certain period of time, the steering angle is suddenly returned to the neutral position, resulting in a sudden steering operation. Therefore, the so-called ＼ending phenomenon, in which the control value goes up or down with respect to the target value, is likely to occur.
The disadvantages were that the steering was jerky and the direction of the traveling aircraft varied in various ways after steering.

In addition, the management machine that applies fertilizer or sprays chemicals at the appropriate time after planting seedlings performs the work while moving along the rows of crops that have already been planted, and the combine harvester that applies fertilizer or sprays chemicals to the unharvested areas and the already harvested areas. Since reaping and threshing operations are performed without moving the grain forward along a substantially straight line between There was a problem that it was difficult to obtain smoothness.

An object of the present invention is to realize smooth and reliable automatic steering control, which has not been possible in the past, in an automatic steering control device for an agricultural machine.

[Means to solve the problem]

Therefore, the present invention provides an apparatus for automatically steering an agricultural machine such as a farm machine so that it runs substantially parallel to and along the rows of crops already planted in a field. a detection means for detecting a row of crops; an instruction amount determining means for determining a steering instruction amount by calculating a deviation of the row of crops with respect to a standard such as straight forward movement of an agricultural machine in response to a signal from the detection means; control amount output means for outputting a steering output signal to the steering drive means in accordance with the determined steering instruction amount, and during a signal output cycle time of the control amount output means, the control amount output means corresponds to the determined steering instruction amount. After the first setting steering output signal is outputted for an appropriate predetermined period of time, a time period is provided in which a second setting steering output signal correcting toward the neutral steering position is outputted.

[Action/effect of the invention]

In the present invention, the instruction amount is determined based on the results of detecting the lateral position of the traveling machine with respect to the crop row and the left and right inclination of the traveling machine in the traveling direction using a detection means such as an imaging means mounted on the traveling machine of the agricultural machine. The means calculates the deviation from the reference (target value) and determines the amount of steering instruction to correct the steering.

The control amount output means outputs a steering output signal to the steering drive IJJ means such as a hydraulic cylinder that changes the direction of the wheels of the traveling aircraft according to the determined steering instruction amount. The output time of the output signal is set to be every cycle of time within a certain range.

Furthermore, in the first time period of this signal output cycle time, the first setting steering output signal corresponding to the determined steering instruction amount is output and held for a certain period of time, and then the first setting steering output signal is corrected toward the neutral steering position. A time period is provided for outputting the two-setting steering output signal, and since the steering is corrected using the so-called two-stage output signal, there is no sudden change in the operation of returning the steering wheel to the original direction.

Therefore, it is possible to realize more detailed steering correction than conventional steering correction using only a single output signal.

As described above, according to the present invention, even in an unmanned automatic steering operation, it is possible to realize a smooth operation that is substantially the same as when an operator actually performs a steering operation.

Therefore, changes in the direction of the traveling machine during corrective steering to follow the crop rows are smooth, and if agricultural work is carried out during this direction change, for example, when a row of seedlings is bent during rice planting work, or when a combine There is no sudden bending of the mowing marks caused by the cutting, and it is possible to take a picture of a good-looking row of crops.

〔Example〕

An example applied to a rice transplanter will be described below. In the figure, l is a running body supported by front wheels 3, 3 on both left and right sides of the front and rear wheels 4.4 on both left and right sides of the rear. At the rear, a multi-row seedling planting device 7 consisting of a seedling platform 5 and a plurality of planting mechanisms 6 is mounted via a link mechanism 8 so as to be movable up and down.

The power of the engine 9 mounted on the top surface of the traveling body 1 is transmitted to the front and rear wheels 3.4 via the clutch 10 and the transmission case 11, while the PTO shaft 2 protruding from the transmission case 11 is connected to the Power is transmitted to the seedling planting device 7. In addition, the code 13 indicates ON/OFF of the clutch 10.
14 is an actuator for traveling speed change, 15 is an actuator for
is an actuator for PTO shaft variable shaft peripheral speed.

The steering mechanism 18 is rotated via a steering handle 17 provided in front of the control seat 16 in the traveling aircraft 1, and the direction of the front wheels 3, 3 is changed from side to side. The steering device is the steering mechanism 18
A steering arm 20 which is horizontally rotatable on a rotational fulcrum shaft 19 in a plan view, and a pair of left and right tie rods 21, 21 connected to the steering arm 20.
, a hydraulic cylinder 22, a control valve 23 for manual steering, and a steering gear box 24 that operates the steering control valve 23, and a pill-man arm 25 that can freely swing back and forth.

The control valve 23 is connected rearward to the steering arm 20 via a ball-and-socket joint, and the spool at the rear end of the control valve 23 is connected to the focusman arm 25.

Further, the rear end of a hydraulic cylinder 22, whose front end is rotatably connected to the traveling body 1, is rotatably connected to the steering arm 20, and swings in accordance with the rotation angle of the control handle 17. The focusman arm 25 moves the spool of the control valve 23 forward and backward, sends hydraulic pressure from the hydraulic pump 26 driven by the engine 9, moves the piston rod in the hydraulic cylinder 22 in and out, and rotates the steering arm 20. Accordingly, change the direction of the left and right front wheels by 3°3.

This hydraulic cylinder 22 is also driven by an electromagnetic solenoid type automatic steering control valve 27, and in this case, the steering angle of the front wheels 3 is determined by a potentiometer 28 attached to the rotation fulcrum shaft 23.
This can be determined by detecting the rotation angle of the steering arm 20 at .

The automatic steering control valve 27 is operated by a steering controller 3 driven by a central control device 30 for automatic steering and driving.
1, and is actuated by the ON/OFF actuator 13 of the clutch 10, the travel shift actuator 14, the PTO shaft circumferential speed actuator 15, and the travel controller 32 driven by the central control device 30. Operate.

The detection device 33 of the present invention includes a tracing imaging means 34 for imaging a row of crops, a feature extraction means 36 for extracting features such as binarization of the image information taken by the imaging means 34, and a feature extraction means 36 for extracting features such as binarization of the image information taken by the imaging means 34. It comprises an image processing controller 38 for processing the features extracted by the means 36 and transmitting necessary information (data) to and from the central control unit 30.

=10 The imaging means 34 is rotatably attached to an arm projecting laterally of the traveling vehicle body 1 or an upright support via a posture maintaining means such as a stenciling motor.

Considering the case where the traveling body 1 moves forward along the side of the crop row, turns around 180 degrees at the end of the crop row, and travels, the imaging means 34 is provided on both the left and right sides of the traveling body 1. It is preferable to provide one.

The imaging means 34 for copying centers the reference line KO of its imaging travel so that it is parallel to the direction of travel on the side of the traveling body 1, and diagonally downward in a forward direction.

The imaging means 34 is an area sensor that detects an object, and has a two-dimensional plane with an imaging screen extending vertically and horizontally like an x-y plane, such as a so-called video camera, and is, for example, a two-dimensional MO3 sensor. In devices with a built-in image sensor or two-dimensional CCD image sensor, the image formed through the lens is sensed by each image sensor (photoelectric device) arranged in a two-dimensional array on the image plane, and then displayed on the imaging screen. 40
This information can be output as an electrical signal.

Further, this imaging means 34 may be either color or black and white, but by using color imaging means 34 for imaging the crop rows, it is possible to distinguish between the field scene and the crop rows and clarify their characteristics. can be recognized.

Next, the traveling body 1 is placed in the field, and after performing the first travel from the edge of the field, it is turned approximately 180 times at the end of the field, and the second travel is performed, and so on, after moving forward in a straight line. Detection device 33 and central control device 30 when performing agricultural work such as rice planting work while traveling back and forth
A schematic flowchart 1- (FIGS. 4-a and 4-b) of the processing executed in FIG.

First, in step S1 following the start, initial values are set, and then in step S2, the operator of the agricultural machine operates the traveling machine 1 to start running adjacent to the crop row. Then,
In step S3, the imaging means 34 is started to operate to begin imaging work, and in step S4, Δ is set to the imaging means 34 for each time.
4 is taken in and stored for each screen in step S5.

FIG. 5 shows a state in which a planted crop location (NAE) is imaged on the imaging screen 40. As shown in FIG.

Next, in step S6, binarization processing is performed to extract and distinguish planting crop locations (NAE) from other field scenes.

In this embodiment, when the copying imaging means 34 is used for color, 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 each color component (red component, green component, and blue component), and the signal output ratio of the green (G) component to the sum of the signal outputs of these three color components (R + G + B = 1) is calculated. When the value is above a predetermined value, it is determined that it is a seedling (crop), and the area (N) where the value can be considered to be almost constant is segmented from other parts of the imaging screen 40 (Segmentation). (See Figure 6).

Note that binarization may be performed using color difference processing in which a portion of color difference image data ((, -B) obtained by subtracting a blue component from a green component of a color line segment is determined to be a seedling) as a seedling.

This binarized feature is stored in the image processing controller 38, the central control unit 30, or the like.

The plurality of plantings obtained by binarizing the image information of the copying imaging means 34 correspond to the crop area (Nl).

(N2), (N3), etc. are simultaneously captured on the imaging screen 40, so in step S7, each binarized planting is performed after calculating the coordinates of the position of the crop.
In step S8, a virtual line Kj2 as the closest straight line approximation to each of the regions (Nl), (N2), (N3), etc. is calculated from the data of the image, and the virtual line Kj2 is calculated from the data of the image.
The declination angle Δρ and the lateral deviation deviation ρ with respect to the reference line KO on the imaging screen 40 of p are calculated.

The calculation of this virtual line KA is performed by a calculation method using software pre-installed in the image processing controller 38, such as the well-known least squares error method or the HOUGH transform method. In the transformation, when a certain point (Xi, Yi) in the XY orthogonal coordinate system is given, all line segments passing through it are ρi = Xicos θ in the polar coordinate system.
It can be expressed as i + Yisin θi.

Therefore, each of the areas (N1) (N
2), (N3)..., the group of line segments is set in polar coordinate system (p i = Xicos θi + Yisin θi)
The Hough process expressed by is executed, the frequency of taking the same ρ and θ is counted as a two-dimensional histogram, the maximum values of ρ0 and θ0 are determined, and β is specified on the virtual straight line of the crop row. .

β is the reference line Ko(
The angle at which the traveling aircraft 1 intersects the Y-axis (which may be the Y-axis along the traveling direction) is defined as the deviation angle Δρ, and the reference point 0 (center position of the imaging screen 40) where the X-axis in the width direction of the traveling aircraft 1 intersects the reference line Ko etc.) to 4 along the virtual straight line along the X-axis direction is defined as a lateral deviation deviation ρ, and these deviations are calculated in step s9.

In addition, when it is on the right side of the reference line Ko on the imaging screen 40, ρ>0, and when it is on the left side, ρ<0.

Further, the case where the virtual line moves one degree to the right of the reference line Ko as it goes upward on the imaging screen 4o is set as Δρ>0, and the opposite case is set as Δρ<0.

Based on the deviation from the standard obtained in this way, step SI
The steering correction control subroutine of O is executed. In this subroutine, in the central control unit 30 having a data storage section, a calculation section, a comparison section, etc., the plurality of deviations ρ, Δρ Fuzzy (Fuz
zy) Fuzzy control applying reasoning, Crisp (C
The steering instruction amount S is calculated according to a control theory such as RI SP) control, and the steering controller 31, for example, the automatic steering control valve 2, which is a steering drive means for rotationally driving the steering wheel,
7, etc., and outputs a steering output signal ■.

That is, step R in the steering correction control subroutine
2, the steering instruction amount S is determined in accordance with the magnitudes of the plurality of deviations ρ and Δρ, and in this case, in the fuzzy control, image processing of the image information obtained by the image pickup means 34 is In order to compensate for the loss of accuracy in detecting crop rows due to high-speed execution, it is possible to obtain a practical control output with less accurate detection values, that is, ambiguous inputs, and also to improve detection accuracy in control. This method is suitable for control when it is difficult to strictly model and describe the relationship between the target condition and the controlled variable, in other words, the relationship between input and output.

In addition, in CRISP control (crisp means crisp or clear), the well-known method of creating a proportional relationship between the input signal and the output signal, or changing the input signal to a variable This is to execute control that defines the output signal according to a certain linear functional relationship.

Next, in step R3, it is determined whether the operation instruction amount S or the deviation is within the allowable range that does not require steering correction, and if it is within the allowable range that does not require steering correction (ye
s), the current state is maintained without any steering correction in step R4.

On the other hand, if it is outside the allowable range, according to the flowchart 1 from step R5 to step R11, the central controller 30 receives the first set steering output signal v1 and the neutral position of the steering according to the numerical value of the steering instruction amount S. A second setting steering output signal V2 having an appropriate value for correcting the direction is output, and the electromagnetic solenoid of the steering control valve 27, which is the steering drive means, is actuated, and the steering arm 2 in the steering mechanism is
The hydraulic cylinder 22 that changes the rotation angle of 0 is driven to perform corrective steering, and automatic steering control is executed in which the traveling machine 1 moves forward in parallel along a predetermined row of crops on the side of the row of crops. .

In this case, the potentiometer 28 that detects the rotation angle of the steering arm 20 determines whether or not the front wheels 3 already have a steering angle that tilts to the right or left with respect to the direction of travel. This can be useful for feedbank control that progresses in parallel with the current state.

In step R5, each value of the first setting steering output signal V1 and the second setting steering output signal V2 having a smaller value is determined according to the numerical value of the calculated steering instruction amount S. This determination is made based on a proportional constant or functional relationship preset in the central controller 30 or the steering controller 31, which is a control amount determining means.

In addition, in step R6, the driving time of the electromagnetic solenoid of the steering control valve 27 is set at each predetermined signal output cycle time (To), and the first set steering output signal is fixed to 1. The time period (tl) to be retained in
, and the time period held in the second setting steering output signal ■2 (
t2) respectively.

Then, in step R7, the first setting steering output signal ■1
The time (tl) is fixed at the value of , and then the second
The set steering output signal (2) is maintained for a period of time (t2), and the output signal is returned to the original value vO, such as 0, in step R9.

In this way, when outputting a steering output signal, the two-stage output signal of the first set steering output signal (■1) and the second set steering output signal (2) having a value correcting toward the neutral position of the steering are sequentially output. By doing so, it is possible to realize a smooth steering correction operation that approximates the steering correction operation actually performed manually by a human being in the automatic steering correction operation.

By executing such automatic steering control, stable steering control is possible, and the followability of steering when traveling substantially parallel to the sides of the crop rows is also improved.

The lengths of each of the first setting steering output signal 1 and the second setting steering output signal V2, as well as the lengths of time periods (tl) and (t2) during which both the output signals are held, are determined as follows. There are variations.

In other words, ■first setting steering output signal■1 and second setting steering output signal V
Each value of 2 is set to increase or decrease in proportion to the calculated value of the steering instruction amount S, and
), (t2) is set to increase or decrease in proportion to the value of the steering instruction amount S.

■The maximum value that the first setting steering output signal ■1 can take is constant regardless of the value of the steering instruction amount S, and the time period (tl) for holding it and each value of the second setting steering output signal ■2 are It is set to increase or decrease in proportion to the value of the steering instruction amount S.

■The maximum value that the first setting steering output signal ■1 can take and the time period (tl) during which it is held constant regardless of the value of the steering instruction amount S, while the value of the second setting steering output signal ■2 is It is set to increase or decrease in proportion to the value of the steering instruction amount S.

■The maximum possible value of the first setting steering output signal v1 and the second
The maximum value that the setting steering output signal ■2 can take is the steering instruction amount S.
is constant regardless of the numerical value of , and the time period (tl) during which the first set steering output signal v1 is held is set to increase or decrease in proportion to the numerical value of the steering instruction (ils).

After making a large correction by making the length of the time period (t2) in which the second setting steering output signal ■2 is held longer than the length of the time period (tl) in which the first setting steering output signal V1 is held. The steering wheel (rudder) can be turned smoothly to provide stable steering operation.

Furthermore, if the length of this time period (t2) is set to increase or decrease in proportion to the calculated value of the steering instruction MS, when the amount of steering instruction is large, the length of the time period (t2) can be set to be close to the target crop row. First setting steering output signal for adding corrective steering■1
While rapidly executing the direction correction steering operation at
The holding time length of the set steering output signal (2) can be increased, and a smoother restoring steering operation can be realized.

Note that the magnitude of the second set steering output signal V2 itself may be set to zero so that the wheels are restored to the neutral position.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view of a riding rice transplanter, FIG. 2 is a side view, and FIG. 3 is a block diagram of an automatic steering/travel control device and an explanatory diagram of its operation including a hydraulic circuit. , 4th-
Figures a and 4-b are control flowcharts, Figure 5 is a diagram of an imaging screen by the scanning imaging means, Figure 6 is a diagram of a binarized imaging screen, and Figure 7 is a diagram of the steering instruction amount S. 1st setting steering output signal ■1 and 2nd setting steering output signal■
This is a time chart of No. 2. ■... Traveling body, 2... Frame, 3, 4...
... Wheels, 5 ... Seedling stand, 6 ... Planting mechanism, 7
... Seedling planting device, 9... Engine, 11...
Mission case, 17...Steering handle, 20.
... Control handle, NAE ... Planting at crop location,
19...Rotation fulcrum shaft, 20...Steering arm, 22...Hydraulic cylinder, 27...Automatic steering control valve, 30...Central control unit, 31... Steering controller, 32... Traveling controller, 33
...Detection device, 34...Imaging means, 36...
- Feature extraction means, 38... image processing controller. Patent applicant Agent: Yanmar Agricultural Machinery Co., Ltd.
People Patent Attorney Akio Hoben

Claims (1)

[Claims] (1) In a device that automatically steers a farm machine such as a farm machine so that it runs substantially parallel to the rows of crops that have already been planted in a field, the machine a detection means for detecting a row; an instruction amount determining means for determining a steering instruction amount by calculating a deviation of the crop row with respect to a standard such as straight forward movement of the agricultural machine in accordance with a signal from the detection means; control amount output means for outputting a steering output signal to the steering drive means in accordance with the steering instruction amount, and a first setting corresponding to the determined steering instruction amount during a signal output cycle time of the control amount output means; An automatic steering control device for an agricultural machine, characterized by providing a time period in which a steering output signal is outputted for a certain period of time and then a second set steering output signal corrected toward a neutral steering position is outputted.