JP7632437B2 - Work vehicles - Google Patents

Description

The present invention relates to a work vehicle such as a rice planter.

There is known a rice transplanter having a planting device that is attached to the vehicle body so that it can be raised and lowered, a steering motor that drives a steering handle, and a control device that controls the vehicle body to move in a straight line by having the steering motor drive the steering handle (see, for example, Patent Documents 1 and 2).

JP 2016-24541 A JP 2002-335720 A

However, work vehicles such as the conventional rice planters described above cannot control the turning of the vehicle body.

The present invention takes into consideration the above-mentioned problems of the conventional technology and aims to provide a work vehicle capable of controlling the turning of the vehicle body.

The first aspect of the present invention comprises a steering member drive device (44) for driving a steering member (52);
A control device (200) for controlling the steering member drive device (44);
Equipped with
A work vehicle in which the control device (200) performs straight-line control when moving a vehicle body (10) straight, performs turning control when turning the vehicle body (10) that has been moving straight, or when stopping the vehicle body (10) that has been moving straight, moving it backward, and turning it after stopping it again, and performs straight-line control after turning when making the turning vehicle body (10) move straight again,
The size of the turning trajectory is determined based on the aircraft travel distance and the aircraft heading,
The timing of returning the steering to make the turning vehicle body (10) go straight again is determined by measuring the vehicle travel distance from the start of the turn until the vehicle heading reaches a predetermined heading, and changing the timing of returning the steering based on the vehicle travel distance;
The control device (200) controls the vehicle speed by regulating the vehicle speed using a first regulation speed and a second regulation speed lower than the first regulation speed in the turning control;
The vehicle speed is restricted by utilizing a second restricted speed at the timing of returning the steering wheel;
When the vehicle body (10) is reversed, the control device (200) regulates the vehicle speed using a third regulation speed not exceeding the second regulation speed;
This work vehicle is characterized in that, when the vehicle is reversed and then stopped again, the steering member (52) is oriented in the turning direction.

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The first aspect of the present invention makes it possible to control the turning of the vehicle body. It is also possible to achieve highly precise control.

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FIG. 1 is a perspective view of a rice transplanter according to an embodiment of the present invention; Block diagram of a power transmission system of a rice transplanter according to an embodiment of the present invention. Block diagram of a control system for a rice transplanter according to an embodiment of the present invention. FIG. 1 is an explanatory diagram of turning control of a rice transplanter according to an embodiment of the present invention; FIG. 1 is an enlarged explanatory diagram of the turning control of a rice transplanter according to an embodiment of the present invention; FIG. 1 is an explanatory diagram of back-turn control of a rice transplanter according to an embodiment of the present invention; FIG. 1 is a partial perspective view of a rice transplanter according to an embodiment of the present invention; FIG. 1 is a partial plan view of a rice transplanter according to an embodiment of the present invention; FIG. 1 is an enlarged partial plan view of the vicinity of an auxiliary wheel of a rice transplanter according to an embodiment of the present invention; FIG. 2 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention (part 2) FIG. 3 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention; FIG. 4 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 5 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 6 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 7 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 8 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 9 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 10 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 11 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 12 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 13 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 14 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 15 is an explanatory diagram of the turning control of the rice transplanter according to the embodiment of the present invention. FIG. 1 is a partial perspective view of the vicinity of an operating unit of a rice transplanter according to an embodiment of the present invention;

The embodiment of the present invention will be described in detail with reference to the drawings.

The same applies below, but some components may not be shown in the drawings or may be shown in perspective or in an omitted form.

The rice transplanter of this embodiment is an example of a work vehicle in the present invention or an invention related to the present invention.

In an alternative embodiment, for example, the work vehicle of the present invention or an invention related to the present invention may be an agricultural tractor.

The steering handle 52 is an example of a steering member in the present invention or an invention related to the present invention. The steering motor 44 is an example of a steering member drive device that drives the steering handle 52 in the present invention or an invention related to the present invention.

The control device 200 is an example of a control device that controls the steering motor 44 in the present invention or an invention related to the present invention.

The vehicle body 10 is an example of a vehicle body in the present invention or an invention related to the present invention. The rear wheel rotation speed sensor 210 and the positioning system 300 are examples of a detection mechanism that detects the turning state of the vehicle body 10 in the present invention or an invention related to the present invention.

The auxiliary wheel 33 is an example of one or more auxiliary wheels attached to at least one of the inside and outside sides of the vehicle body 10 in the left-right direction of the vehicle body in the present invention or in an invention related to the present invention.

The rear wheel 32 on the inside of the turn is an example of a specific wheel in the present invention or an invention related to the present invention.

First, the configuration and operation of the rice transplanter of this embodiment will be specifically described with reference to Figures 1 and 2.

Here, FIG. 1 is a perspective view of a rice transplanter according to an embodiment of the present invention, and FIG. 2 is a block diagram of the power transmission system of the rice transplanter according to an embodiment of the present invention.

While explaining the operation of the rice transplanter of this embodiment, we will also explain the travel control method of an invention related to the present invention.

The rice transplanter in this embodiment is a riding mat seedling rice transplanter that plants eight rows, and the planting device 100 has four planting units, each of which has two planting tools, one on the left and one on the right.

The rice planting machine is not limited to a riding mat seedling rice planter that plants eight rows, but may also be, for example, a riding pot seedling rice planter that plants ten rows.

First, the basic configuration and operation of the rice transplanter of this embodiment will be explained. Therefore, turning control and other aspects will be explained in detail later.

The driving unit 50 has a seat 51 located above the engine 20.

A steering handle 52 for operating the front wheels 31 is provided in front of the seat 51. Horizontal step floors are provided on both the left and right sides of the engine 20. Furthermore, a spare seedling carrying platform 101 is provided on the vehicle body 10.

The running device 30 is a device that causes the vehicle body 10 to run using the front wheels 31 and rear wheels 32.

The ground leveling device 60 is a device that levels the field using a ground leveling rotor mechanism 61 and a ground leveling float mechanism 62.

The line-drawing marker 80, which creates straight line markings in the field as a guide for the next planting travel route, is attached so that it can be stored in the vehicle body 10.

The planting device 100 is attached to the rear of the vehicle body 10 via a planting device lifting device 90.

The rotational power of the engine 20 attached to the main frame is transmitted to the main transmission mechanism 41, which is an HST (Hydro Static Transmission) mechanism. The rotational power that has been changed in speed by the main transmission mechanism 41 and the sub-transmission mechanism 42 is separated into running power used by the running device 30 and the like, and externally extracted power used by the planting device 100 and the like.

A portion of the running power is transmitted to the left and right front wheel final cases to drive the pair of left and right front wheels 31, and the remainder of the running power is transmitted to the left and right rear wheel gear cases 43 to drive the pair of left and right rear wheels 32. Then, a portion of the running power transmitted to the rear wheel gear cases 43 is transmitted to the ground leveling device 60 and the fertilizer application device 70.

Next, the configuration and operation of the rice transplanter of this embodiment will be described in more detail, mainly with reference to Figures 1 to 3.

Figure 3 is a block diagram of the control system of a rice transplanter according to an embodiment of the present invention.

The control device 200 is a device that performs various controls using not only the lever operation of the main speed change lever 53, the sub speed change lever 54, or the straight-line assist lever 55, and the switch operation of the assist mode switch 56, but also the detection results of the rear wheel rotation speed sensor 210 or the planting device lift sensor 220.

The positioning system 300 is, for example, a system that performs positioning using DGPS (Differential Global Positioning System) technology that utilizes GPS (Global Positioning System), a typical GNSS (Global Navigation Satellite System).

Driving control requires consideration of a comprehensive range of factors, including the size of the vehicle body 10, the responsiveness of the steering motor 44, and the condition of the field. Even if the positioning system 300 were extremely accurate, it would be difficult to achieve precise driving control, and various attempts have been made.

In straight-line control, the coordinates of point A, which corresponds to the start point of straight-line driving where planting work is performed, and point B, which corresponds to the end point of straight-line driving, are registered in advance using a positioning system 300 that acquires current orientation information for the vehicle body 10. Then, straight-line control is realized by driving the steering motor 44 to perform steering so that straight-line driving is performed based on a virtual line connecting points A and B.

However, the straight-line control must be turned on and off every time a turn requires manual steering, which places a significant burden on the operator and does not necessarily provide sufficient operability or workability.

Therefore, it is desirable to realize not only straight-line control but also turning control that automatically aligns rows based on the distance between planting rows, and the following basic turning control is considered.

Of course, it goes without saying that the turning control method described below can be used in various turning controls. Specifically, one of those various turning controls is, for example, turning control in which no straight-line movement is included during turning, the steering angle is kept almost constant during turning, and the turning path of the vehicle body 10 is a roughly semicircular path.

(A1) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, mainly with reference to Figures 4 and 5.

Here, FIG. 4 is an explanatory diagram (part 1) of the turning control of a rice transplanter according to an embodiment of the present invention, and FIG. 5 is an enlarged explanatory diagram of the turning control of a rice transplanter according to an embodiment of the present invention.

The rice transplanter of this embodiment is a rice transplanter in which the control device 200 performs turning control when turning the vehicle body 10 that has been moving straight.

The control device 200 determines the turning state based on the detection results and controls the steering angle based on the turning state determination.

For example, in the automatic turning control of a rice transplanter, the steering angle is fixed at a constant α (for example, 45 degrees) during automatic turning so that the machine does not move straight during the turn. When a turning route is set using GPS and the machine turns along that route, control can be difficult and unstable. In addition, moving the steering wheel during turning changes the rotation of the rear wheel on the inside of the turn, which makes so-called Z-turns and other controls unstable. By keeping the steering angle constant, control is easy and the machine is highly versatile for use with aircraft of various specifications. Because the steering angle is constant, the rotation of the rear wheel on the inside of the turn is stable, and it is easy to determine without additional sensors that if the number of rotations of the inner rear wheel is small, the machine is making a small turn, and if the number of rotations is large, the machine is making a large turn.

The control device 200 controls the steering angle by changing the timing of returning the steering angle based on the turning state determination in order to make the turning vehicle body 10 move straight again.

The steering angle return timing is the timing at which the difference between the direction of the vehicle body 10 being turned and the direction in which the vehicle body 10 is moving straight again falls below a predetermined steering angle return level.

For example, the steering angle return level is 30 degrees.

The timing of steering angle return can be adjusted based on a manual operation that adjusts a predetermined steering angle return level.

For example, the steering angle return level may be reduced to 25 degrees or increased to 35 degrees by dialing the threshold adjustment device 400 based on the operator's experience.

The timing at which the turning state is determined is the timing of the position of arrow A, which is determined based on the direction such as the aircraft heading or the aircraft perpendicular heading, distance, time, GNSS position, vehicle speed, etc. The turning state is determined based on the direction, distance, time, GNSS position, vehicle speed, etc.

For example, the size of the turning trajectory is determined with ample time at a timing when the aircraft heading is 45 degrees, which is the difference between the direction of the turning vehicle body 10 and the direction in which the vehicle body 10 will move straight again.

If it is determined that the turning trajectory of the vehicle body 10 starting from the turning start position Ps on the straight line Lv0, which is the previous process line, is a standard-sized turning trajectory C0, the steering angle is returned to the standard 30-degree steering angle return level position P0 without changing the steering angle return timing. Even without changing the steering angle return timing, the vehicle body 10 can enter the straight control handover zone Z upon reaching the virtual line Lh0 just before the planting start line Lh, so a smooth handover to the straight control is performed to automatically move the vehicle body 10 straight again along the straight line Lv.

The handover from turning control to straight-line control occurs, for example, when entry into straight-line control handover zone Z is recognized based on the GNSS position.

To ensure a smooth handover to the straight-line control, it is desirable that, as the vehicle approaches the next process line, the straight-line line Lv, the entry angle to the straight-line line Lv as well as the steering angle are not too large just before the straight-line control handover zone Z.

The inventors have arrived at the idea of ensuring a smooth transition to straight-line control, regardless of turning conditions that are easily affected by factors such as field conditions, by changing the timing at which the steering angle is returned based on a turning condition judgment.

Specifically, the timing of steering angle return is changed based on the judgment of the size of the turning trajectory as follows:

If it is determined that the turning trajectory is a tight turning trajectory C1, the steering angle is returned not at the timing of position P1, which is the standard 30 degree steering angle return level, but, for example, at the timing of position Q1, which is a steering angle return level of 35 degrees, which is greater than 30 degrees. Then, even if the turning trajectory is a tight turning trajectory C1, the vehicle body 10 can approach the straight line Lv and enter the straight control handover zone Z, so that a smooth handover to straight control is performed in the same way.

If it is determined that the turning trajectory is a large turn trajectory C2, the steering angle is returned not at the timing of position P2, which is the standard 30 degree steering angle return level, but, for example, at the timing of position Q2, which is a steering angle return level of 25 degrees, which is less than 30 degrees. Then, even if the turning trajectory is a large turn trajectory C2, the vehicle body 10 can enter the straight-line control handover zone Z without moving away from the straight-line line Lv, so that a smooth handover to straight-line control is performed in the same way.

Of course, the timing of steering return may be changed based on the direction in this way, but it may also be changed based on distance, time, GNSS position, or vehicle speed, etc., so that the path of travel is corrected for a smooth transition to straight-line control.

Incidentally, in turning assist correction control using rear wheel pulses, the pulses of the rear wheel on the inside of the turn are measured from the start of automatic turning control until the turn begins in order to know the rear wheel rotation speed used to determine the size of the turning trajectory. The number of pulses of the inside rear wheel during automatic turning is less affected by slippage, etc., and it can be determined whether the turning operation is normal.

In the automatic turning control of rice transplanters, the number of pulses of the rear wheel on the inside of the turn is measured from the start of automatic turning control until the machine's heading reaches a specified heading (θ0). θ0 is set to 45 degrees or more. A decision is made as to whether or not to add a correction to the automatic turning control based on the number of pulses of the rear wheel at the time when the machine's heading is θ0. If θ0 is 45 degrees or less, even if a correction is added to the automatic turning control, the control may not be able to keep up and turning accuracy may deteriorate.

If the number of pulses at this time is between p1 and p2, it is determined that the turn is normal and no correction control is performed. By setting the range from p1 to p2 for the appropriate rear wheel pulse value on the inside of the turn during automatic turning control, unnecessary correction control is not performed and turning accuracy can be improved.

When the number of pulses p is p ≥ p2, it is determined that the turn is wide, and the steering return start direction is delayed to move the aircraft closer to the inside and align the start of the turn. If it is determined that a wide turn is being made based on the rear wheel rotation speed, the steering return start direction can be controlled to move the aircraft closer to the inside, aligning the start of the turn and improving turning accuracy.

When the pulse count p is p≦p1, it is determined that the turning is tight, and the steering return start direction is delayed or advanced so that the aircraft is closer to the outside and the start of the turning is synchronized. If it is determined that the turning is tight from the rear wheel rotation speed, the steering return start direction is controlled so that the aircraft is on the outside, so that the start of the turning can be synchronized and turning accuracy can be improved.

The magnitude of the turning trajectory may thus be determined based on the magnitude of the rear wheel rotation rate at the position where the aircraft heading reaches a predetermined angle, but conversely, it may also be determined based on the magnitude of the aircraft heading at the position where the rear wheel rotation rate reaches a predetermined number. For example, if the magnitude of the aircraft heading at the position where the rear wheel rotation rate reaches a predetermined number is small, it may be determined that the turn is a large turn, and the steering return start direction may be delayed to align the aircraft with the start of planting on the inside.

Ultimately, the timing at which the turning state determination is performed is determined based on one or more physical quantities selected from the heading, distance, time, GNSS position, or vehicle speed, and the turning state is determined based on similar physical quantities, but the combination of these physical quantities is arbitrary. For example, the timing at which the turning state determination is performed may be determined based on distance and GNSS position, and the turning state determination may be determined based on the heading and vehicle speed.

The timing of steering angle return is changed based on one or more physical quantities selected from the heading, distance, time, GNSS position, vehicle speed, etc., but the physical quantity on which the steering angle control is based, such as the change in the steering angle return timing, may be determined independently or dependently from the combination of physical quantities described above. For example, the timing at which the turning state determination is made may be determined based on time, the turning state determination may be determined based on the vehicle speed, and the steering angle return timing may be changed based on the heading and GNSS position.

The control device 200 may maintain the steering angle at a constant angle until the turning state determination timing at which the turning state determination is performed, and then control the steering angle by changing the constant angle based on the turning state determination.

When the number of pulses p is p ≥ p2, it is determined that the vehicle is turning wider, and the steering angle α, which is a fixed angle, is increased to make the vehicle turn tighter. If it is determined that the vehicle is turning wider from the rear wheel rotation speed, the steering control is performed to make the vehicle turn tighter, thereby improving the turning accuracy.

When the number of pulses p is p≦p1, it is determined that the vehicle is turning in a tighter direction, and the constant steering angle α is turned back to make a wider turn. If it is determined that the vehicle is turning in a tighter direction based on the rear wheel rotation speed, the steering control is performed to make a wider turn, thereby improving turning accuracy.

It goes without saying that a fixed angle change, such as increasing or decreasing the steering angle α, may be performed simultaneously with the determination of the turning state, or may be performed, for example, 0.2 seconds after the determination of the turning state.

The control device 200 may control the steering angle by changing the steering angle return speed, which returns the steering angle, based on the turning state determination in order to make the turning vehicle body 10 move straight again.

Of course, the steering angle return speed may be changed instead of or in conjunction with changing the timing of the steering angle return so that the travel path can be properly corrected. For example, the aircraft heading at which the steering angle is returned may be constant, and only the steering angle return speed may be changed.

It goes without saying that the steering angle may be returned simultaneously with the determination of the turning state, or, for example, 0.2 seconds after the determination of the turning state.

In a configuration where the steering angle return speed is adjustable, even if the timing for determining the turning state is very close to the timing for returning the steering angle, the steering angle can be returned without delay by increasing the steering angle return speed.

(A2) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, mainly with reference to Figure 6.

Figure 6 is an explanatory diagram of the backturn control of a rice transplanter according to an embodiment of the present invention.

The rice transplanter of this embodiment is a rice transplanter in which the control device 200 performs turning control when the vehicle body 10, which has been moving straight, is stopped, moved backward, stopped again, and then turned.

After driving straight back from point S1 to point S2, a turn from point S2 to point S5 via points S3 and R4 is performed automatically or semi-automatically.

Of course, it is also possible to configure the system so that turning assist control is not started when the turning control is in a mode in which the HST is automatically controlled, such as the so-called "pinch planting control" and "pinch approach control." This is because if turning assist is started by mistake with "pinch approach," unintended operation of the HST may occur. Therefore, it is desirable to prevent unintended HST operation.

Here, we will explain the first to eighth reverse patterns in the backturn control, in which the vehicle body 10 that was moving straight is stopped, moved backward, stopped again, and then turned.

(First reverse pattern)
The first reverse movement pattern is a reverse movement pattern in which the vehicle moves backward in a straight line.

In the rice transplanter turning assist control, during back-turn control, a configuration is considered in which the motor control keeps the steering wheel moving straight from the start of reverse movement to the stop of reverse movement (1.1 m). By moving backwards in a straight line when reversing, it is possible to prevent position deviation until the machine turns to head toward the next target line.

(Second reverse pattern)
The second reverse pattern is a reverse pattern in which the steering wheel is turned in front of the vehicle.

When the vehicle body 10 is reversed, the control device 200 maintains the steering angle at zero until a predetermined timing, and then changes the steering angle toward the turning direction by a predetermined steering angle amount.

In other words, during back-turn control in the rice transplanter turning assist control, a configuration is considered in which the motor control is used to keep the steering wheel moving straight from the start of reverse movement until 30 cm before the reverse stop (1.1 m). By moving backwards straight when reversing, position deviation is prevented until the machine heads toward the next target line when turning.

In the rice transplanter turning assist control, during the back-turn control, after the above control, that is, from 30 cm before the reverse stop (1.1 m) to the reverse stop (1.1 m), a configuration is considered in which the steering wheel is turned at a certain angle in the turning direction by motor control. If the steering wheel is turned when the vehicle starts moving forward, the travel path will not be stable depending on the vehicle speed. The vehicle may make a wide turn and hit the bank. Also, if the steering wheel is not turned while traveling, the motor may not be able to turn the steering wheel because it will be unable to withstand the load of the field. By turning the steering wheel to a certain degree in the turning direction before turning, the travel path when turning forward will be stable and wide turns can be prevented. Therefore, it is preferable to turn the steering wheel while traveling backward.

The predetermined steering angle is the amount of steering angle at which the transmission of driving force to the rear wheel 32 on the inside of the turn attached to the vehicle body 10 is not cut off.

In other words, a possible configuration would be to aim for a steering angle that does not disengage the rear wheel clutch (220 degrees). This is because if the steering wheel is turned enough to disengage the rear wheel clutch, the vehicle's travel path will change suddenly, as if it were quick turning, and it will move backwards, which will not only damage the planting area with the tires, but will also cause stalks to be missing and make the vehicle's travel path unstable when turning.

(Third reverse pattern)
The third reverse pattern is a reverse pattern in which the vehicle backs up in the final straight heading direction.

In the rice planter turning assist control, during backturn control, a configuration is considered in which the steering wheel is steered based on the direction of the last straight-line assist from the start of reverse to the stop of reverse (1.1 m). This is because the straight-line assist control usually forces the vehicle to stop 3 m before the bank, so a person must manually plant at least 3 m, and the manually planted area may deviate from the straight-line assist path, and there is a risk that the path after the turning assist and the path before it will no longer be 30 cm apart (depending on the model). In particular, with irregularly shaped rice fields, people have a habit of turning the steering wheel to enter the bank perpendicularly, so they enter in a bow shape and back up in that state, and back up in a direction different from the original planting path, which reduces the disadvantage of an unstable turning path.

(Fourth reversing pattern)
The fourth reverse pattern is a reverse pattern that is aligned with the final straight path line.

In the rice transplanter turning assist control, during backturn control, a configuration is conceivable in which the steering wheel is steered based on the path on which the last straight-line assist was performed from the start of reverse movement to the end of reverse movement (1.1 m).

(Fifth reverse pattern)
The fifth reverse movement pattern is a reverse movement pattern that is aligned with the ideal reverse stop position coordinates obtained from the final route.

In the rice transplanter turning assist control, during backturn control, from the start of reverse movement to the stop of reverse movement (1.1 m), a configuration is conceivable in which the steering wheel is steered with a coordinate point moved an arbitrary reverse distance (1.1 m) in the reverse direction of the last straight path as a target point from a coordinate point perpendicular to the last straight path and a perpendicular line obtained by rotating the last straight path 90 degrees from the current machine position.

(Sixth reverse pattern)
The sixth reverse pattern is a reverse pattern in which a period is intentionally provided in which the steering wheel is turned in the opposite direction to the turning direction.

In the rice transplanter turning assist control, during back-turn control, a configuration is considered in which the motor control is set to turn the steering wheel at a certain angle in the opposite direction to the turning direction during a period between the start of reverse movement and the end of reverse movement (1.1 m).

(Seventh reverse pattern)
The seventh reverse pattern is a reverse pattern in which a period is intentionally set aside to turn in a different direction.

In the rice transplanter turning assist control, during backturn control, a period can be set in which the steering wheel is steered in a direction shifted by an arbitrary angle from the direction in which the last straight-line assist was performed between the start of reverse travel and the end of reverse travel (1.1 m).

(Eighth reverse pattern)
The eighth reverse pattern is a reverse pattern in which a period is intentionally set aside to switch to a different route.

In the rice transplanter turning assist control, during back-turn control, a configuration is conceivable in which the steering wheel is steered to a path that is shifted in any direction from the path on which the last straight-line assist was performed between the start of reverse travel and the end of reverse travel (1.1 m) (e.g., 10 cm closer to or farther from the travel path or turning path).

In reverse patterns such as the first to eighth reverse patterns when turning backward, the vehicle is controlled to automatically stop after moving backward a certain distance (1.1 m), but if the vehicle stops suddenly when moving backward at high speed, the stopping shock is large and may be dangerous for the operator. In addition, between 30 cm before the reverse stop (1.1 m) and the reverse stop (1.1 m), the vehicle is controlled to turn the steering wheel ahead of the vehicle in the direction of the turn so that the rear wheel clutch does not disengage (aiming for 220 degrees of steering). However, if the steering wheel is turned while traveling at high speed, the travel path is not stable, and the vehicle may reach the reverse stop (1.1 m) position before the steering wheel is turned completely, and the vehicle may have to turn the steering wheel while stopped. In particular, in the case of deep wet rice fields, the motor may be unable to turn the steering wheel when the vehicle is stopped because of the load of the field. Therefore, when controlling the back turn, it is desirable to control the vehicle speed while taking safety into consideration.

When forward operation is performed after reverse movement is completed in the various configurations described above, a configuration is conceivable in which the steering wheel is turned at a fixed angle in the turning direction by motor control. By turning the steering wheel in the turning direction, automatic turning becomes possible without the need for a human to operate the steering wheel.

In other words, when you start turning, the steering wheel is already turned.

Here, we will explain the turning assist handle steering for so-called U-shaped turning control, which includes going straight while turning.

A U-shaped turn is a turn such as a turn from point S2 to point S5 via points S3 and R4, regardless of whether the backing straight ahead described above is performed.

The following describes the steering control completion step for starting a turn (1). When the steering state has already been achieved at the start of a turn in the previous step, a configuration is conceivable in which the steering operation is completed when the aircraft's heading deviates from the target heading by a certain angle (75 degrees) or more. The steering operation end conditions are clarified, and the start conditions for an 8-row U-shaped turn are given.

The following describes the (2) steering wheel center control step during turning. If the steering wheel turning operation is completed in the previous step, a configuration is considered in which the steering wheel is driven by the motor to a straight-ahead state. When making a U-shaped turn, the steering wheel is turned a certain distance to make the turn, and then the steering wheel is straightened once. This allows for a clearer turning operation.

The following describes the step of completing center steering control during turning (2). A possible configuration is to complete the straight steering operation when the counter of the rear wheel rotation sensor reaches a certain value or more in the previous step, that is, when the straight-line portion of the U-shaped turn has been completed. This clarifies the condition for ending the straight steering operation.

The steering control step for starting a turn (2) will now be described. If the steering wheel has been operated to go straight in the previous step, a possible configuration is to turn the steering wheel a certain angle in the direction of the turn (turning the steering wheel toward the turning direction). When making a U-shaped turn, the steering wheel is turned after driving straight for a certain distance, which allows for a clear turning operation.

The steering control completion step for starting a turn (3) will now be described. A possible configuration is to complete the steering operation when the deviation of the aircraft's heading from the target heading becomes less than a certain angle (depending on conditions) while the aircraft is traveling in the direction of travel after turning in the previous step. This clarifies the conditions for ending the steering operation.

The following describes the step of starting a turn (4) controlling the steering wheel to go straight. If the steering wheel has been turned in the previous step, a configuration is possible in which the steering wheel is driven to go straight. Once the U-shaped turn is completed, the steering wheel is turned to go straight. This allows for a clearer turning operation.

The following describes the step of completing the straight-line steering control at the start of turning (4). A possible configuration is to complete the straight-line steering operation when the steering wheel returns to within a certain straight-line range in the previous step. This clarifies the conditions for ending the turning assist operation.

The straight-line assist control start step will be explained. A possible configuration is to start straight-line assist after the handlebars have been moved straight in the previous step. Turn start (4) When the handlebars straight-line control is completed, the machine will automatically start straight-line assist after the turn is completed based on the path after the turn, allowing turning and planting work to be continued by simply operating the HST lever. In addition, since the travel path is based on the path after the turn, the distance between adjacent rows of 30 cm (depending on the model) is appropriately maintained.

The turning assist control completion step will now be explained. A possible configuration is to consider turning assist control completed when one turning operation has been completed in the previous step. This clarifies the conditions for ending the turning assist operation.

In the straight-line assist control start step, the straight-line assist after turning can be configured to automatically steer with parameters different from the normal straight-line assist steering parameters until the aircraft is on the target line. If the aircraft deviates from the target path after turning assist, it may take time to return to the target path by steering the steering wheel, but by making the steering parameters stronger (increasing the amount of steering) after turning assist, it is possible to return to the target path more quickly and produce neater planting marks.

It is possible to configure the steering parameters to be changeable by using a checker, dial, switch operation, etc. The return response can be changed depending on the field conditions.

The steering parameters can be configured to revert to normal straight-line assist steering parameters once the vehicle is on the target line. If steering remains harsh even after the vehicle is on the target line, the steering wheel may begin to hunt (diverge). However, by clarifying the conditions for switching parameters, automatic steering with normal steering parameters will be possible once the vehicle is on the target line, without the need for any operation.

It is possible to configure the counter setting of the rear wheel rotation sensor in the straight-line range to be arbitrarily changed during turning at the (2) steering wheel center control completion step. By setting the counter to 0, it is possible to skip the process from the (1) steering wheel turning control completion step to the (2) steering wheel turning control step at the start of turning, making it possible to make a large one-point turn.

It is possible to consider a configuration that omits the steps from the step of starting turning (1) completing steering control to the step of starting turning (2) controlling steering. When making a U-shaped turn, the turning trajectory may become unstable depending on the field conditions (slippage, etc.), but by omitting the U-shaped turn in the first place, the stability of the turn is increased. In addition, the wheel marks when turning are also cleaned up, and the field is not damaged.

A possible configuration is to reduce the turning end angle in the steering control completion step (3) when the vehicle speed is slow. If the vehicle speed is slow, the distance traveled between turning the steering wheel and returning it to the center position is short, which can result in a wide turn. However, by reducing the turning end angle and delaying the timing of returning the steering wheel to the center position when the vehicle speed is slow, it is possible to appropriately steer the vehicle toward the target path.

At the start of turning (3) steering control completion step, a possible configuration is to increase the turning end angle if the vehicle speed is high. If the vehicle speed is high, the distance traveled between turning the steering wheel and returning it to the center position is long, resulting in tighter turning radius. If the vehicle speed is low, the turning end angle is increased and the timing of returning the steering wheel to the center is accelerated, allowing the vehicle to make an appropriate turning path toward the target path.

At the start of turning (3) steering control completion step, the turning end angle can be changed depending on the number of threads on the aircraft. The turning radius and working width differ depending on the number of threads, and therefore the target path to be aimed for differs. By changing the turning end angle depending on the number of threads, it is possible to appropriately steer the turning path toward the target path.

When the turning end angle is set to 7 rows at the start of turning (3) steering control completion step, a possible configuration is to change it between a so-called 3-row straddle and a 5-row straddle. With 7 rows, the turning radius and working width differ depending on the number of straddle rows, so the target path may differ, but by changing the turning end angle depending on the number of straddle rows, it is possible to appropriately adjust the turning path toward the target path.

A configuration is conceivable in which the turning end angle is corrected (-2 degrees) when an internal auxiliary wheel is present at the turning start (3) steering control completion step. When auxiliary wheels are attached, the turning radius becomes larger, resulting in a larger turn, which may change the turning trajectory, but by changing the turning end angle by setting the auxiliary wheels, the turning path can be made appropriate toward the target path. A configuration is conceivable in which the turning end angle is corrected (-2 degrees) when an external auxiliary wheel is present at the turning start (3) steering control completion step. When auxiliary wheels are attached, the turning radius becomes larger, resulting in a larger turn, which may change the turning trajectory, but by changing the turning end angle by setting the auxiliary wheels, the turning path can be made appropriate toward the target path. When both internal and external auxiliary wheels are attached (triple configuration), an external priority configuration is conceivable in which correction is made by prioritizing the external auxiliary wheel setting. In the case of a triple configuration, the influence of the external wheels is large, but double correction of the internal and external wheels is prevented. By changing the turning end angle by setting the auxiliary wheels, the turning path can be made appropriate toward the target path.

When both internal and external auxiliary wheels are attached (triple configuration), a triple setting configuration can be considered that performs dedicated correction for the turning end angle. By changing the turning end angle through the auxiliary wheel settings, it is possible to make the turning path appropriate toward the target path, making correction settings unique to the triple configuration possible. A configuration is possible in which the correction value can be changed to any value using a checker or monitor settings. The parameters can be changed to the user's preference depending on the field conditions.

Not only in this type of turn-assisted handle steering for U-shaped turn control, but also in the first to eighth reverse patterns in the back-turn control described above, a configuration can be considered in which the timing for starting to turn the steering wheel is changed depending on the number of teeth. In the case of six teeth, the steering wheel is turned 60 cm before, and in the case of seven or eight teeth, the steering wheel is turned 30 cm before. This is because if the steering wheel is turned 30 cm before in the case of six teeth, the turning trajectory will not match, and it may not be possible to properly enter the target route after turning.

(B) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, mainly with reference to Figures 7 to 9.

Here, FIG. 7 is a partial perspective view of a rice transplanter according to an embodiment of the present invention, FIG. 8 is a partial plan view of a rice transplanter according to an embodiment of the present invention, and FIG. 9 is an enlarged partial plan view of the vicinity of the auxiliary wheel 33 of a rice transplanter according to an embodiment of the present invention.

The rice transplanter of this embodiment is a rice transplanter in which the control device 200 performs turning control when turning the vehicle body 10 that has been moving straight.

The control device 200 changes the timing of returning the steering angle to the original position to cause the vehicle body 10 to move straight again, based on the installation state of the auxiliary wheels 33.

The standard steering angle return timing is set as the steering angle return timing when the auxiliary wheels 33 are not installed.

In the automatic turning control of a rice transplanter, the number of pulses p of the rear wheel on the inside of the turn is measured from the start of automatic turning control until the machine's heading becomes θ0. If the number of pulses at this time is between p1 and p2, it is determined that the turn is normal and no correction control is performed.

When the auxiliary wheels 33 are attached to the inside in the left-right direction of the vehicle body but not to the outside in the left-right direction of the vehicle body, the control device 200 changes the steering angle return timing so that the steering angle return timing is later than the standard steering angle return timing.

When the internal auxiliary wheels 33 are installed, the appropriate values p1 to p2 change, so when the internal auxiliary wheels 33 are installed, the controller settings can be adjusted to adjust the standard for determining the turning state without adjusting the standard steering angle return timing itself, and the appropriate values p1 and p2 can be changed. By setting the width from p1 to p2 for the appropriate rear wheel pulse value on the inside of the turn during automatic turning control, unnecessary correction control is not performed and turning accuracy can be improved. In addition, when the internal auxiliary wheels 33 are installed, the rear wheel resistance during turning changes and the appropriate rear wheel rotation speed also changes. By changing the values p1 and p2 in the controller settings, high-precision automatic turning control is possible even when the internal auxiliary wheels 33 are installed.

When the auxiliary wheels 33 are attached to the outside in the left-right direction of the vehicle body but not to the inside in the left-right direction of the vehicle body, the control device 200 changes the steering angle return timing so that the steering angle return timing is earlier than the standard steering angle return timing.

When external auxiliary wheels 33 are attached, the appropriate values p1 to p2 change, so when external auxiliary wheels 33 are attached, the controller settings may be made to adjust the standard for determining the turning state without adjusting the standard steering angle return timing itself, and the appropriate values p1 and p2 may be changed. By setting a width from p1 to p2 for the appropriate rear wheel pulse value on the inside of the turn during automatic turning control, unnecessary correction control is not performed and turning accuracy can be improved. In addition, when external auxiliary wheels 33 are attached, the rear wheel resistance during turning changes, and the appropriate rear wheel rotation speed also changes. By changing the values p1 and p2 in the controller settings, highly accurate automatic turning control is possible even when external auxiliary wheels 33 are attached.

When the auxiliary wheels 33 are attached to the inside and outside of the vehicle body in the left-right direction, the control device 200 changes the steering angle return timing so that the steering angle return timing is earlier than the standard steering angle return timing.

The control device 200 determines the turning state based on the detection results, and changes the timing of steering angle return based not only on the mounting state of the auxiliary wheels 33 but also on the turning state determination.

(C) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, mainly with reference to Figures 4 and 6.

The rice transplanter of this embodiment is a rice transplanter in which the control device 200 performs turning control when turning the vehicle body 10 that has been moving straight.

The control device 200 controls the vehicle speed during turning control.

In the rice transplanter turning assist control, during U-turn control, after control is started by the planting lift operation, that is, during turning from planting lift, a configuration is considered in which the normal maximum forward speed of 1.86 m/s (depending on the model) is restricted to 0.9 m/s. This is because the travel distance from the start of forward movement until the steering wheel is turned to the target position varies depending on the vehicle speed, and if the steering wheel is turned while moving forward at high speed, the vehicle will naturally make a wide turn and the travel trajectory will not be stable.
By regulating the vehicle speed, the vehicle's driving trajectory during cornering is stabilized.

During U-turn control, the maximum forward speed limit is not capped at 0.9 m/s or more, but is instead gradually capped at 0.9 m/s when the HST lever is in the maximum forward speed position. This is because if the speed limit is capped at 0.9 m/s or more, the HST lever will reach the upper limit of the limit of 0.9 m/s at an intermediate position, making fine adjustments difficult and resulting in a poor operating feel as the vehicle speed does not change despite the lever being operated. This makes it easier to fine-tune the vehicle speed even when the speed is restricted, improving the operating feel.

The control device 200 controls the vehicle speed by regulating the vehicle speed using a first speed limit and a second speed limit that is smaller than the first speed limit. The second vehicle speed regulation period in the turning control, during which the vehicle speed is regulated so as not to exceed the second speed limit, is a period following the first vehicle speed regulation period in the turning control, during which the vehicle speed is regulated so as not to exceed the first speed limit.

At least near the timing when the turning control ends, the vehicle speed is regulated so as not to exceed the second regulated speed.

During U-turn control, if the turn ends during the above-mentioned control and the difference in the aircraft's traveling direction from the target direction becomes less than a specified angle (50 degrees) while proceeding in the direction of the next turning target line, a configuration can be considered in which the maximum forward speed limit of 0.9 m/s (first speed limit) is further restricted to 0.6 m/s (second speed limit). This is because, as a control specification, when the aircraft approaches the direction of the target line, the steering wheel is returned to the center and automatic steering begins toward the turning target line, but if the vehicle is traveling at high speed while turning the steering wheel, the traveling path becomes unstable and the angle of entry to the target line becomes unstable. Restricting the vehicle speed stabilizes the traveling trajectory when turning.

The control device 200 performs straight-line control after a turn when the vehicle body 10 that has been turned is made to go straight again. At least near the start timing of the straight-line control at which the straight-line control after a turn starts, the vehicle speed is restricted so as not to exceed the second restricted speed.

Of course, there may also be an embodiment in which the vehicle speed is restricted so as not to exceed the second restricted speed even after the straight-line control start timing.

For example, during U-turn control, the maximum forward speed is restricted to 0.6 m/s, and automatic steering is engaged after the turn is completed, and this restriction continues until the vehicle reaches the target line even during trajectory correction toward the target line. A possible configuration is to restrict vehicle speed until the vehicle reaches the target line. This is because if the vehicle speed restriction is released after automatic steering is engaged after the turn is completed, the vehicle will travel at a high speed until it reaches the target line, which may result in a correspondingly longer distance until the planting mark becomes straight. By restricting vehicle speed even after the turn is completed, the vehicle's travel trajectory until it reaches the target line is stabilized.

When the vehicle body 10 reaches the vicinity of the straight-line control target line for straight-line control after turning, the vehicle speed restriction is released.

Of course, there may be an embodiment in which the vehicle speed restriction is not lifted even after the vehicle body 10 reaches the vicinity of the straight-line control target line for straight-line control after turning.

For example, during U-turn control, the maximum forward speed of 0.6 m/s can be restricted by automatic steering after the turn is completed, and this restriction continues even during trajectory correction toward the target line until the planting clutch is engaged, so a configuration can be considered in which the vehicle speed is restricted with planting engaged. This is because if the vehicle speed restriction is released after automatic steering is engaged after the turn is completed, the vehicle speed will be high until it reaches the target line, which may result in a correspondingly longer distance until the planting mark becomes straight. By restricting the vehicle speed even after the turn is completed, the driving trajectory until it reaches the target line can be stabilized.

During the first vehicle speed regulation period, the vehicle speed regulation takes priority even if a manual operation is performed to adjust the vehicle speed so that it exceeds the first vehicle speed regulation.

During the second vehicle speed regulation period, the vehicle speed regulation takes priority even if a manual operation is performed to adjust the vehicle speed so that it exceeds the second vehicle speed regulation.

During U-turn control, the HST's vehicle speed return response speed when the vehicle speed restriction is released can be configured to return more slowly than during normal lever operation. This is because, although there is a possibility of endangering the operator if the vehicle speed were to return suddenly after control ends, this ensures safety.

Vehicle speed regulation can be achieved by restricting the HST trunnion opening based on the theoretical vehicle speed at the HST lever position. This clarifies the method of vehicle speed regulation, and since it is determined only by the lever position, vehicle speed regulation can be easily achieved.

A possible configuration would be to use a rear wheel rotation sensor to detect the current vehicle speed during speed restrictions, and if it is determined to be slower than the target vehicle speed, increase the trunnion opening to increase the vehicle speed. Depending on the field conditions, the vehicle speed may fluctuate even with the same trunnion opening, but this allows the vehicle to turn at a stable speed depending on the field conditions.

A possible configuration would be to use a rear wheel rotation sensor to detect the current vehicle speed during speed restrictions, and if it is determined to be faster than the target vehicle speed, reduce the trunnion opening to slow down the vehicle speed. Depending on the field conditions, the vehicle speed may fluctuate even with the same trunnion opening, but this would allow the vehicle to turn at a stable speed depending on the field conditions.

A possible configuration would be to use GPS to detect the current vehicle speed during speed restrictions, and if it is determined to be slower than the target speed, increase the trunnion opening to increase the vehicle speed. Depending on the field conditions, the vehicle speed may fluctuate even with the same trunnion opening, but this would allow the vehicle to turn at a stable speed depending on the field conditions.

One possible configuration is to use GPS to detect the current vehicle speed during speed restrictions, and if it is determined to be faster than the target vehicle speed, reduce the trunnion opening to slow down the vehicle speed. Depending on the field conditions, the vehicle speed may fluctuate even with the same trunnion opening, but this allows the vehicle to turn at a stable speed according to the field conditions.

It is possible to detect the GPS vehicle speed using the average value over a certain period of time (0.5 seconds, 1 second, etc.). The GPS vehicle speed is not very stable, so if it is judged based on an instantaneous value, there will be fluctuations, but using the average value improves the accuracy of vehicle speed detection.

When calculating the average value of the GPS vehicle speed obtained at fixed intervals (0.1 seconds), it is possible to perform detection using GPS, omitting the maximum and minimum values. GPS vehicle speed is unstable, so if it is judged based on the instantaneous value, there will be fluctuations and abnormal values may be received momentarily due to its characteristics, but the accuracy of vehicle speed detection can be improved by thinning out the maximum and minimum values.

If the currently calculated GPS average vehicle speed Vn is significantly different from the GPS average vehicle speed Vn-1 calculated one cycle ago (e.g. by more than 1.0 m/s), the currently calculated GPS average vehicle speed Vn is judged to be abnormal, and the GPS average vehicle speed Vn-1 calculated one cycle ago is treated as the positive value for control. A possible configuration is to perform detection using GPS. Since GPS vehicle speed is not very stable, there will be fluctuations when judging it based on an instantaneous value, and due to its characteristics, it may receive an abnormal value momentarily, but the accuracy of vehicle speed detection can be improved by thinning out the abnormal values.

It is possible to configure the vehicle speed monitoring (whether it is fast or slow) to be performed at fixed intervals (0.5 seconds, 1 second, etc.) rather than at the main control interval (10 ms, etc.). This is because if the monitoring interval is too short, the vehicle speed will not be stable and the HST will be constantly under feedback control, which will cause hunting and reduce occupant comfort.

It is conceivable that the appropriate range for vehicle speed monitoring (whether it is fast or slow) could be set to a certain threshold (such as allowing up to ±0.1 m/s). This is because if the appropriate range for vehicle speed is too narrow, the HST will be constantly under feedback control, which can lead to hunting and reduced comfort.

The opening of the HST, which is corrected by monitoring the vehicle speed (whether it is fast or slow), can be configured to target a certain vehicle speed range (0.1 m/s). It is necessary to determine the appropriate value for how much correction should be made at one time, so the vehicle speed can be adjusted gradually without making a correction all at once.

If the current vehicle speed is significantly different from the target vehicle speed, a configuration that repeats the above-mentioned content at regular intervals is conceivable. By repeating feedback control, smooth vehicle speed correction is possible.

The opening of the HST to be corrected can be stored in a non-volatile manner in the controller, and the correction opening can be changed in a non-volatile manner using a checker or dial operation on the monitor panel. The response of the vehicle speed correction can be made faster or slower depending on the situation.

The opening of the HST to be corrected can be changed by operating an external dial, and a configuration is conceivable in which the correction opening can be changed with a dial. While operating a checker or digging into a deep hierarchy on the monitor can be cumbersome, it makes it easy to speed up or slow down the response of the vehicle speed correction depending on the situation.

One possible configuration is to simultaneously feedback control the engine speed by controlling the electric accelerator as well as the trunnion opening of the electric HST. This is because in deep fields such as wet rice paddies, if the HST opening is increased alone, the engine may stop due to engine drop.

It is possible to configure the system to perform feedback control of the HST and electric accelerator even during normal driving, not just when cornering assistance is in progress. This would enable driving control according to the HST lever position even during normal driving, regardless of field conditions.

It is possible to configure the system so that feedback control is not performed when the sub-transmission is at the travel speed. This is because if control that automatically corrects the HST opening is activated while driving on the road, there is a risk that the vehicle will drive differently from what the operator intended (the vehicle will automatically accelerate), which could lead to a dangerous situation, so it is desirable not to perform automatic driving corrections while driving on the road.

It is possible to configure the system so that feedback control is not performed when the planting section is raised. This is because if the sub-transmission is at planting speed while driving on the road and control is activated to automatically correct the HST opening, there is a risk that the vehicle will drive differently from what the operator intends (it will automatically accelerate), which could lead to a dangerous situation, so it is desirable not to perform automatic driving corrections when not working.

It is possible to configure the system so that feedback control is not performed when the planting clutch is off. This is because if the sub-transmission is at planting speed while driving on the road and control is applied to automatically correct the HST opening, there is a risk that the vehicle will drive differently from what the operator intends (it will automatically accelerate), which could lead to a dangerous situation. There is also the possibility that the planting section may be lowered below a certain height depending on the situation, such as to avoid obstacles, and the vehicle may drive on the road. Therefore, it is desirable not to automatically correct driving when not working, and to only use the planting clutch when it is engaged, i.e., when rice planting is in progress, the control is not effective.

One possible configuration would be to store the feedback control on/off setting in a non-volatile manner held by the controller, and then change the setting on/off in a non-volatile manner using a checker or dial operation on the monitor panel. This is because some users do not want to make vehicle speed corrections because it changes the feeling they get, and it is desirable to be able to turn vehicle speed correction on and off depending on the situation.

It is possible to consider a configuration in which feedback control can be switched on or off by operating an ON/OFF switch, or the like, and the setting can be changed by changing the setting. This is because some users do not want to make vehicle speed corrections because it changes the feeling they get, and it is desirable to be able to turn vehicle speed correction on and off depending on the situation.

During the second vehicle speed regulation period, the vehicle speed is regulated to match the second regulated speed. During the first and second vehicle speed regulation periods, if a manual operation is performed to adjust the vehicle speed so that it falls below the second regulated speed, the vehicle body 10 is stopped.

One possible configuration is to fix the HST opening to a neutral position during U-turn control at very low forward speeds, preventing driving. This is because when turning assistance is performed at very low speeds, the GPS information can vary greatly and the vehicle can be easily affected by the field, making turning unstable. When automatic steering is turned on after the turn is completed, if the vehicle is not traveling at a certain speed or above, an error at low speeds can cause the automatic steering to be cut off. By restricting turning assistance at unstable speeds, it is possible to make smooth turns with a stable driving trajectory and prevent the occurrence of automatic steering errors after turning.

When a ridge warning is initiated during U-turn control (approximately 8 m before the ridge), a configuration is considered in which the normal maximum forward speed of 1.86 m/s (depending on the model) is restricted to 0.9 m/s. This is because, as mentioned above, when U-turn control is initiated while traveling at high speed, the travel distance from the start of forward movement until the steering wheel is turned to the target position varies depending on the vehicle speed, and turning the steering wheel while traveling at high speed naturally results in a wide turn and an unstable travel trajectory. Smooth U-turn control is possible by reducing the vehicle speed to a certain extent before U-turn control begins.

A possible configuration is for the vehicle speed to be restricted in stages according to the distance from the ridge. In one example configuration, the restricted vehicle speed is set every 2m in accordance with the ridge-edge warning, at 1.3m/s above 8m, 1.2m/s from 6m to 8m, 1.1m/s from 4m to 6m, 1.0m/s from 2m to 4m, and 0.9m/s below 2m. This is because if the vehicle speed is restricted too far in advance, it will take longer than necessary to reach the target ridge-edge position.

The response speed of the HST when speed restriction begins could be configured to return more slowly than with normal lever operation. This is to ensure safety, as changes in vehicle speed could pose a danger to workers.

One possible configuration is for the vehicle speed restriction control at the edge of a field to continue until the HST lever is returned to the vehicle speed restriction position. This is because the vehicle speed restriction control at the edge of a field is basically set up to automatically stop the vehicle 3 meters before the vehicle, so it is not possible to drive to the position where the vehicle actually wants to make a U-turn, and if the vehicle continues to drive after the vehicle speed restriction control has been activated, it would be meaningless if the vehicle speed restriction did not work if the driver turned off the automatic steering wheel at the edge of a field. If the driver turns off the automatic steering wheel at the edge of a field, the vehicle speed restriction can continue until the person operates the lever voluntarily, even if the HST lever position remains the same until the vehicle reaches the U-turn start position, allowing for smooth U-turn control.

It is possible to configure the vehicle speed restriction control at the edge of a field to be released when U-turn control is initiated. This is because if the vehicle speed restriction at the edge of a field were to continue indefinitely, it would conflict with the vehicle speed restriction during turning assistance, and the control would no longer be effective. This clarifies the conditions for releasing the vehicle speed restriction at the edge of a field.

It is possible to consider a configuration in which the vehicle speed restriction control on the edge of a field is released when the U-turn control is turned off (U-turn switch OFF). This is because if the vehicle speed restriction on the edge of a field is continued for a long time, it may collide with the vehicle speed restriction during turning assistance, or the restriction may continue even though it should be released when turning assistance is turned off. This clarifies the conditions for releasing the vehicle speed restriction on the edge of a field.

The control device 200 also performs turning control when the vehicle body 10, which has been traveling straight, is stopped, moved in reverse, stopped again, and then turned. When the vehicle body 10 is moved in reverse, the control device 200 restricts the vehicle speed by using a third restricted speed that does not exceed the second restricted speed.

Of course, an embodiment is also conceivable in which, when the vehicle body 10 is reversed, the control device 200 regulates the vehicle speed using a third regulation speed that does not exceed the first regulation speed.

For example, in rice transplanter turning assist control, a configuration is conceivable in which the maximum reverse speed is normally 1.2 m/s and is restricted to 0.9 m/s from the start of reverse movement during backturn control until 30 cm before the reverse stop (1.1 m). This is because, in a control that automatically stops after reversing a certain distance (1.1 m) when turning backward, if the vehicle is reversed at high speed and then suddenly stopped, the stopping shock is large and may pose a danger to the operator, but safety is ensured.

During the back-turn control in the rice transplanter turning assist control, after the above-mentioned control, that is, from 30 cm before the reverse stop (1.1 m) to the reverse stop (1.1 m), a configuration is considered in which the maximum reverse speed limit of 0.9 m/s is further restricted to 0.5 m/s (third restricted speed). This is because, from 30 cm before the reverse stop (1.1 m) to the reverse stop (1.1 m), there is a control to turn the steering wheel in advance to the extent that the rear wheel clutch is not disengaged in the turning direction (aiming for 220 degrees of steering), but if the steering wheel is turned during high-speed driving, the driving path may not be stable, and the reverse stop (1.1 m) position may be reached before the steering wheel is completely turned, which may cause a problem that the steering wheel must be turned while the vehicle is stopped (especially in the case of deep wet rice fields, there is a risk that the motor will not be able to turn the steering wheel when the vehicle is stopped due to the load of the field). In addition, the above-mentioned control allows the vehicle to travel a certain distance without excessively restricting its speed, and by restricting the vehicle speed to a certain extent in the lead, it is possible to suppress the shock of shifting gears 30 cm before the reverse stop (1.1 m) while also suppressing the shock of stopping at the reverse stop (1.1 m).

It goes without saying that the various controls described above for U-turn control can be used not only for U-turn control but also for back-turn control.

For example, during back-turn control in rice transplanter turning assist control, after the reverse control for backing up straight as described above, that is, during turning from a stop in reverse, a configuration can be considered in which the normal maximum forward speed of 1.86 m/s (depending on the model) is restricted to 0.9 m/s.

(D) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, mainly with reference to Figures 4 and 6.

The rice transplanter of this embodiment is a rice transplanter in which the control device 200 performs straight-line control before turning when the vehicle body 10 that is turned is made to go straight, performs turning control when the vehicle body 10 that has been made to go straight is turned, and performs straight-line control after turning when the turned vehicle body 10 is made to go straight again.

Switching from straight-line control to turning control before turning is performed manually.

Of course, there may be embodiments in which the switch from straight-line control before a turn to turning control is performed automatically, as is the switch from turning control to straight-line control after a turn, and there may also be embodiments in which the switch from turning control to straight-line control after a turn is performed based on manual operation.

The timing for returning the steering angle to return the vehicle body 10 that has been turned to move straight again is set as a timing before the straight-line control start timing for starting straight-line control after turning.

The steering angle return timing is the timing at which the difference between the direction of the vehicle body 10 being turned and the direction in which the vehicle body 10 is moving straight again falls below a predetermined steering angle return level.

As mentioned above, for example, the steering angle return level is 30 degrees.

The timing of steering angle return can be adjusted based on a manual operation that adjusts a predetermined steering angle return level.

As described above, for example, the steering angle return level may be reduced to 25 degrees or increased to 35 degrees by dialing the threshold adjustment device 400 based on the operator's experience.

(E) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, mainly with reference to Figures 10 to 24.

Here, Figures 10 to 23 are explanatory diagrams (parts 2 to 15) of the rotation control of a rice transplanter according to an embodiment of the present invention, and Figure 24 is a partial perspective view of the vicinity of the operation unit 50 of a rice transplanter according to an embodiment of the present invention.

<Turning assist correction control using Z-turn (1)> (see FIG. 10)
In the automatic turning control of the rice transplanter, the steering angle is fixed at a constant α during automatic turning. The Z-turn is designed to send a signal to lower the planting part when the rice transplanter has turned 135°.

The turning route is set using GPS, and the drone turns along that route, which makes it difficult to control and unstable.

By keeping the steering angle constant, control is easy and it is highly versatile for aircraft with various specifications. Because the steering angle is constant, the rotation of the rear wheel on the inside of the turn is constant, improving Z-turn control accuracy.

<Turning assist correction control using Z-turn (2)> (see FIG. 10)
The aircraft orientation during automatic turning control of the rice transplanter is measured by the IMU, and if the planting section lowering signal is not issued when the aircraft reaches an angle of θ1 (if the rear wheel on the inside of the turn is not rotating more than the design value), it is determined that the aircraft is making a tight turn, and corrective control is performed to return the steering angle α to make a wider turn.

By utilizing Z-turn control to correct the turning assist control, existing programs and sensors can easily determine whether or not the turning radius needs to be corrected, improving turning accuracy.

<Turning assist correction control using Z-turn (3)> (see FIG. 10)
The aircraft orientation during automatic turning control of the rice transplanter is measured by the IMU, and if a planting unit lowering signal is issued when the aircraft reaches an angle of θ2 (when the rear wheel on the inside of the turn is rotating more than the design value), it is determined that the aircraft is making a wide turn, and correction control is performed by increasing the steering angle α to make a tighter turn.

By utilizing Z-turn control to correct the turning assist control, existing programs and sensors can easily determine whether or not the turning radius needs to be corrected, improving turning accuracy.

<Turning assist correction control using Z-turn (4)> (see FIG. 11)
The rice transplanter's aircraft direction during automatic turning control is measured by the IMU, and if the planting section lowering signal is not issued when the aircraft reaches an angle of θ1 (if the rear wheel on the inside of the turn is not rotating faster than the design value), it is determined that the machine is making a tight turn, and the steering return direction is accelerated to ensure that the planting tracks are aligned.

By utilizing Z-turn control to correct the turning assist control, existing programs and sensors can easily determine whether or not the turning radius needs to be corrected, improving turning accuracy.

<Turning assist correction control using Z-turn (5)> (see FIG. 12)
The aircraft direction during automatic turning control of the rice transplanter is measured by the IMU, and if a signal to lower the planting section is issued when the aircraft reaches an angle of θ2 (when the rear wheel on the inside of the turn is rotating more than the design value), it is determined that the aircraft is making a wide turn, and the steering return direction is delayed to control the planting tracks so that they are aligned.

By utilizing Z-turn control to correct the turning assist control, existing programs and sensors can easily determine whether or not the turning radius needs to be corrected, improving turning accuracy.

<Turning assist correction control using Z-turn (6)> (see FIG. 13)
The angles θ1 and θ2 for determining whether or not to perform the turning assist correction control are set to 140° or less.

By setting θ1 and θ2 to 140° or less, even if correction control is activated, it is possible to prevent deterioration of turning accuracy due to correction not being made in time.

<Three-point turning assist control (1)> (see FIG. 14)
In the automatic turning control of the rice transplanter, the steering angle is fixed at a constant α during automatic turning.

The turning route is set using GPS, and the drone turns along that route, which makes it difficult to control and unstable.

The constant steering angle makes it easy to control and highly versatile for aircraft with various specifications.

<Three-point turning assist control (2)> (see FIG. 14)
In the automatic turning control of a rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning at a constant steering angle are obtained from GNSS antenna information.

By obtaining the coordinates, it is possible to check whether the aircraft is rotating as planned.

<Three-point turning assist control (3)> (see FIG. 15)
In the automatic turning control of a rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The coordinates of the three obtained points are substituted into the following equation, and the simultaneous equations are solved to obtain the turning radius R1, and it is monitored whether the turning radius is being controlled as planned ( ^x2 + ^y2 + lx + my + n = 0).

By calculating the turning radius, it is possible to determine whether the aircraft is turning at the planned turning radius.

<Three-point turning assist control (4)> (see FIG. 15)
In the automatic turning control of a rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The obtained coordinates of the three points are substituted into the following formula, and the simultaneous equations are solved to obtain the turning radius R1 and monitor whether the turning radius is being controlled as planned ( ^x2 + ^y2 + lx + my + n = 0). If the obtained turning radius R1 is Ra (lower limit of appropriate turning radius) ≦ R1 ≦ Rb (upper limit of appropriate turning radius), it is determined that the turning is normal, and the turning continues without any correction.

The accuracy of turning can be improved by determining whether the turn is normal or not for each turn based on the measured turning radius.

<Three-point turning assist control (5)> (see FIG. 15)
In the automatic turning control of a rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The obtained coordinates of the three points are substituted into the following formula, and the simultaneous equations are solved to obtain the turning radius R1 and monitor whether the turning radius is being controlled as planned ( ^x2 + ^y2 + lx + my + n = 0). When the obtained turning radius R1 is Rb≦R1, it is determined that the turning radius is large, and the steering angle is controlled to make the turning radius small.

If the measured turning radius indicates that the vehicle is making a large turn, the steering can be controlled to make the turn smaller, improving turning accuracy.

<Three-point turning assist control (6)> (see FIG. 15)
In the automatic turning control of a rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The coordinates of the three obtained points are substituted into the following equation, and the simultaneous equations are solved to obtain the turning radius R1 and monitor whether the turning radius is being controlled as planned ( ^x2 + ^y2 + lx + my + n = 0). If the obtained turning radius R1 is R1 ≦ Ra, it is determined that the turning radius is small, and the steering angle is controlled to return to a larger turning radius.

If the measured turning radius indicates that the vehicle is making a tighter turn, the steering can be controlled to make a wider turn, improving turning accuracy.

<Three-point turning assist control (7)> (see FIG. 16)
In the automatic turning control of a rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The obtained coordinates of the three points are substituted into the following formula, and the simultaneous equations are solved to obtain the turning radius R1 and monitor whether the turning radius is being controlled as planned ( ^x2 + ^y2 + lx + my + n = 0). If the obtained turning radius R1 is Rb ≦ R1, it is determined that a large turn is being made, and the steering return direction at the end of the turn is delayed so that the planting marks are on the inside, and the tillage marks are controlled to be aligned.

If the measured turning radius determines that the turn is wide, the steering return direction at the end of the turn is delayed to align the tilling start position with the previous process, improving the accuracy of the turning assist control.

<Three-point turning assist control (8)> (see FIG. 17)
In the automatic turning control of the rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The obtained coordinates of the three points are substituted into the following formula, and the simultaneous equations are solved to obtain the turning radius R1 and monitor whether the turning radius is being controlled as planned ( ^x2 + ^y2 + lx + my + n = 0). If the obtained turning radius R1 is R1 ≦ Ra, it is determined that the machine is turning in a tighter direction, and the steering return direction at the end of the turn is accelerated so that the planting marks are on the outside, and the tillage marks are controlled to be aligned.

If it is determined from the measured turning radius that the turning is becoming tighter, the steering return direction at the end of the turn can be accelerated to align the start of tilling with the previous process, improving the accuracy of the turning assist control.

<Three-point turning assist control (9)> (see FIG. 18)
In the automatic turning control of the rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The position information is obtained so that θ1, θ2, and θ3 are values that are 30° or more apart.

If three points are obtained at small angles to calculate the turning radius, there is a high risk that the error will be large and the turning radius will not be calculated accurately.

By acquiring position coordinates that are 30° or more away and calculating the turning radius, it is possible to calculate a highly accurate turning radius, improving the accuracy of turning assist control.

<Three-point turning assist control (10)> (see FIG. 19)
In the automatic turning control of the rice transplanter, the coordinates of the machine turning angles θ1, θ2, and θ3 during automatic turning with a constant steering angle are obtained from GNSS antenna information. The position information is obtained so that θ1, θ2, and θ3 are values that are 30° or more apart. In addition, θ3 is 120° or less.

Even if you try to correct turning control based on a turning radius obtained at 120° or more, the control may not be able to keep up, and turning accuracy may decrease.

By determining whether or not to correct the turning control before turning 120 degrees, the effect of making the correction can be fully realized, improving the accuracy of the turning assist control.

<Straight-line assist control (1)>
In a straight-line assisted rice transplanter, the IMU detects the tilt of the machine in the rolling direction, and if the machine continues to tilt in one direction for a certain period of time, it is determined that the wheels are stuck in a rut, and the steering amount dial value is automatically changed to the larger side.

If the steering amount is small when the vehicle is stuck in a rut, the amount of steering control during straight-line control will be small, and straight-line accuracy will deteriorate. Also, it will be impossible to get out of the rut.

By automatically increasing the amount of steering, straight-line driving accuracy is improved. It also allows the vehicle to escape ruts sooner, improving straight-line driving.

<Straight-line assist control (2)>
In the straight-line assisted rice transplanter, the IMU detects the tilt of the machine in the rolling direction, and if the machine continues to tilt in one direction for a certain period of time, it determines that the wheels are stuck in a rut and automatically changes the steering amount dial value to the larger side. Also, if it determines that the machine has remained horizontal for a certain period of time, it automatically returns the steering amount to the original value.

If you continue to turn the steering wheel too much even after you have left the rut, the steering control may be too large and you may start swerving.

When the vehicle returns to a horizontal position, the steering angle automatically returns to the original amount, improving straight-line accuracy.

<Improvement of Turning Assist Control (1)> (See FIG. 20)
In the turning assist control, a steering angle α is set according to a turning target distance for each model, and during turning control, the vehicle is turned at the fixed steering angle α.

Previously, the farmer would turn the steering wheel to a stationary position and then return the steering wheel midway through the turn to make the farmer run sideways to align the rows, but the distance traveled sideways could be unstable depending on the field conditions, leading to poor row alignment. This eliminates the unstable factor caused by sideways running. Also, turning with the steering wheel fixed is simpler than using a method of specifying a route using GNSS or similar to control the farmer, and is stable and not affected by GNSS sensitivity.

By fixing the steering angle during turning according to each model and number of threads, unstable factors caused by lateral running are eliminated, and thread alignment can be stabilized, and the control is simple and highly versatile. Also, turning can be stabilized without being affected by GNSS.

It is now possible to change from a U-shaped turn to a U-shaped turn.

<Improvement of Turning Assist Control (2)> (See FIG. 20)
In the turning assist control, when the steering angle for each type is set, the turning radius differs for each type, and the control is performed to change the back amount L during a back turn according to the turning radius.

Changing the steering angle changes the turning radius, but if the amount of backing up when backing up is constant, there is a problem of running onto the ridge when the turning radius becomes large, or backing up too far and crushing seedlings.

By changing the steering angle, the turning radius changes, and by setting the amount of backing accordingly, optimal turning can be achieved, improving work efficiency.

<Improvement of Turning Assist Control (3)> (See FIG. 20)
In the turning assist control, a steering angle α is set according to a turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right turns and left turns, respectively.

Due to variations in parts, the turning radius differs for each aircraft even with the same steering angle, so the precision of turning assist control can be improved by configuring the system to set the turning angle to suit each aircraft.

<Improvement of Turning Assist Control (4)> (See FIG. 20)
In the turning assist control, the steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The steering angle α can be set for right and left turns, respectively. The value can also be adjusted with a dial on the monitor (e.g., 1 memory steering 5°).

The accuracy of turning assistance can be improved by configuring it so that it can be fine-tuned to suit field conditions.

<Improvement of Turning Assist Control (5)> (See FIG. 20)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right and left turns, respectively. The value can also be adjusted using a dial on the monitor. The vehicle is also configured to automatically change the appropriate amount of backing according to the adjusted turning angle.

L': Back amount L: Specified back amount K: Adjustment coefficient α: Turn angle J: Turn angle adjustment value by dial L' = L K (α + J)
As the turning radius increases, it is necessary to keep a distance to the ridge, and if the backing distance is constant, there is a problem of running over the ridge when the turning radius is increased.

By changing the amount of backing up in conjunction with changing the steering angle, it is possible to prevent the vehicle from running onto ridges while turning or crushing seedlings when backing up, and it is possible to stabilize turning assistance.

<Improvement of Turning Assist Control (6)> (See FIG. 21)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The steering angle α can be set separately for right and left turns. In addition, in order to adjust the turning accuracy according to the field conditions, the vehicle azimuth angle β at which the steering wheel (circled number 4 in the figure) starts to return to a straight ahead state can be adjusted with a dial on the monitor.

By configuring the system to allow fine adjustment of the timing at which the steering starts to return to a straight-ahead position, turning assistance can be tailored to the field conditions, improving accuracy.

<Improvement of Turning Assist Control (7)> (See FIG. 21)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right and left turns. The value can also be adjusted with a dial on the monitor (e.g., 1 memory steering 5°). The aircraft azimuth angle β, at which the steering wheel (number 4 in a circle in the figure) begins to return to a straight ahead state, is changed in conjunction with the adjusted turning angle.

β': Aircraft azimuth angle when steering wheel return begins β: Aircraft azimuth value when steering wheel return begins K: Adjustment coefficient J: Turn angle adjustment value by dial β' = β K (α + J)
The accuracy of turning assistance can be improved by changing the timing at which the steering begins to return to a straight-ahead position in conjunction with the steering angle.

<Improvement of Turning Assist Control (8)> (See FIG. 21)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right and left turns, respectively. The value can also be adjusted with a dial on the monitor (e.g., 1 memory steering 5°). In accordance with the adjusted turning angle, the aircraft azimuth angle β at which the steering wheel (number 4 in a circle in the figure) begins to return to a straight ahead state is changed in conjunction with the steering angle, and the amount of backing up during backing up is also changed in conjunction with the steering angle.

The accuracy of turning assistance can be improved by changing the timing at which the steering wheel begins to return to a straight-ahead position and the amount of backing up in conjunction with the steering angle.

<Improvement of Turning Assist Control (9)> (See FIG. 22)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right turning and left turning, respectively. The vehicle speed during turning is also detected, and the turning angle α is changed in conjunction with the vehicle speed. The higher the vehicle speed V, the larger the turning angle α is set, thereby suppressing the change in turning radius due to the vehicle speed.

α': Turning angle during turning C: Adjustment coefficient V: Vehicle speed during turning α: Specified steering angle α' = C V α
The turning radius can be stabilized by changing the steering angle according to the vehicle speed.

<Improvement of Turning Assist Control (10)> (See FIG. 23)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right turning and left turning, respectively. In addition, the angular velocity γ during turning is detected, and the turning angle α is changed in conjunction with the angular velocity. The higher the vehicle speed V, the larger the turning angle α is set, thereby suppressing the change in turning radius due to the vehicle speed.

α': Turning angle during turning C: Adjustment coefficient γ: Angular velocity during turning α: Specified steering angle α' = C γ α
The turning radius can be stabilized by changing the steering angle according to the angular velocity during turning.

<Improvement of Turning Assist Control (11)> (See FIG. 23)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right and left turns. The HST lever opening degree during turning is detected, and the turning angle α is changed in conjunction with the HST lever. The larger the HST lever opening degree R, the larger the turning angle α can be, thereby suppressing changes in the turning radius due to vehicle speed.

α': Turning angle during turning C: Adjustment coefficient R: HST lever opening α: Specified steering angle α' = C R α
The turning radius can be stabilized by changing the steering angle according to the HSTB lever opening.

<Improvement of Turning Assist Control (12)> (See FIG. 21)
In the turning assist control, a steering angle α is set according to the turning target distance for each model, and during turning control, the vehicle is turned at a fixed steering angle α. The turning angle α can be set for right and left turns, respectively. The value can also be adjusted using a dial on the monitor. The vehicle is also configured to automatically change the appropriate amount of backing and the timing to start returning the steering wheel in accordance with the adjusted turning angle.

L': Back amount L: Specified back amount K: Adjustment coefficient α: Turn angle J: Turn angle adjustment value by dial L' = L K (α + J)
β': Aircraft azimuth angle when steering wheel return begins β: Aircraft azimuth value when steering wheel return begins K: Adjustment coefficient J: Turn angle adjustment value by dial β' = β K (α + J)
As the turning radius increases, it is necessary to keep a distance to the ridge, and if the backing distance is constant, there is a problem of running over the ridge when the turning radius is increased.

By changing the amount of backing up in conjunction with changing the steering angle, it is possible to prevent the vehicle from running onto ridges while turning or crushing seedlings when backing up, and it is possible to stabilize turning assistance.

<Turning Assist Z-Turn Correction (1)>
In the rice transplanter Z-turn control, during turning assistance, the timing N1 of lowering the planting section, which is determined by the detection of the rear wheel rotation sensor, is corrected (+20 pls).

The turning assist control results in larger turns than normal, so the timing of the Z-turn is not right (it's too early). If you want to time the Z-turn, the user has to operate the checker or monitor themselves.

When turning assist is enabled, Z-turn correction is automatically performed, reducing the user's effort.

<Turning Assist Z-Turn Correction (2)>
In the rice transplanter Z-turn control, during turning assistance, the planting clutch engagement timing N2 determined by the detection of the rear wheel rotation sensor is corrected (+20 pls).

The turning assist control results in larger turns than normal, so the timing of the Z-turn is not right (it's too early). If you want to time the Z-turn, the user has to operate the checker or monitor themselves.

When turning assist is enabled, Z-turn correction is automatically performed, reducing the user's effort.

<Turning Assist Z-Turn Correction (3)>
In the configuration of the turning assist Z-turn correction (1), the N1 correction is changed depending on the number of threads on the aircraft.

The turning radius and working width vary depending on the number of rows, so the target route will also differ.

By changing the amount of Z-turn correction depending on the number of threads, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (4)>
In the configuration of the turning assist Z-turn correction (1), the N1 correction is configured to change between three-row and five-row crossings when the seven-row setting is used.

The turning radius and working width vary depending on the number of straddling rows, so the target route varies.

By changing the amount of Z-turn correction depending on the number of straddle strips, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (5)>
In the configuration of the turning assist Z-turn correction (1), the N1 correction is changed (+30 pls) when an internal auxiliary wheel is present.

The turning radius and working width differ depending on the auxiliary wheels, so the target route will also differ.

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (6)>
In the configuration of the turning assist Z-turn correction (1), the N1 correction is changed (+30 pls) when external auxiliary wheels are present.

The turning radius and working width differ depending on the auxiliary wheels, so the target route will also differ.

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (7)>
In the configuration of the turning assist Z-turn correction (1), the N1 correction is configured to prioritize the external auxiliary wheel setting when both internal and external auxiliary wheels are attached (triple) and perform correction (external priority version).

In the case of triple wheels, the impact of external wheels is large. This prevents double correction by internal and external wheels.

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (8)>
In the configuration of the turning assist Z-turn correction (1), the N1 correction is a configuration (triple setting version) that performs a dedicated correction when both internal and external auxiliary wheels are attached (triple).

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible. Triple's unique correction settings are possible.

<Turning Assist Z-Turn Correction (9)>
In the configuration of the turning assist Z-turn correction (2), the N2 correction is changed depending on the number of threads on the aircraft.

The turning radius and working width vary depending on the number of rows, so the target route will also differ.

By changing the amount of Z-turn correction depending on the number of threads, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (10)>
In the configuration of the turning assist Z-turn correction (2), when the N2 correction is set to 7 rows, it is configured to change between 3 rows and 5 rows.

The turning radius and working width vary depending on the number of straddling rows, so the target route varies.

By changing the amount of Z-turn correction depending on the number of straddle strips, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (11)>
In the configuration of the turning assist Z-turn correction (2), the N2 correction is changed (+40 pls) when an internal auxiliary wheel is present.

The turning radius and working width differ depending on the auxiliary wheels, so the target route will also differ.

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (12)>
In the configuration of the turning assist Z-turn correction (2), the N2 correction is changed (+40 pls) when external auxiliary wheels are present.

The turning radius and working width differ depending on the auxiliary wheels, so the target route will also differ.

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (13)>
In the configuration of the turning assist Z-turn correction (2), when both internal and external auxiliary wheels are attached (triple), the N2 correction is configured to give priority to the external auxiliary wheel setting and perform correction (external priority version).

In the case of triple wheels, the impact of external wheels is large. This prevents double correction by internal and external wheels.

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible.

<Turning Assist Z-Turn Correction (14)>
In the configuration of the turning assist Z-turn correction (2), the N2 correction is a configuration (triple setting version) that performs a dedicated correction when both internal and external auxiliary wheels are attached (triple).

By changing the amount of Z-turn correction using the auxiliary wheels, appropriate turning assistance and Z-turns are possible. Triple's unique correction settings are possible.

<Turning Assist Z-Turn Correction (15)>
The correction values of the turning assist Z-turn corrections (1) to (14) can be changed to any value using a checker or monitor settings.

Users can change parameters to suit their preferences depending on field conditions.

<Rice transplanter turning assist monitor guidance display (1)> (see FIG. 24)
In the rice transplanter turning assist control, the marker monitor lamp during left turning is configured to flash the left lamp in the turning direction periodically (on time 500 ms, period 1 second, etc.) from the start to the end of the turning assist.

During auto marker operation (conditions for turning assist), when the planting section rises, the marker monitor lamp does not move in the direction of turning, but lights up in the opposite direction to the direction it is currently in. In other words, when turning left, the marker is out on the left and the lamp is on the left, but when making a back turn, the marker lamp automatically lights up in the opposite direction. This means that although the direction in which the steering wheel is turned to the left when turning is the left, the lamp is on to the right, which makes the worker feel uncomfortable (this is actually a marker lamp and not a turning direction lamp, so the operation is correct but it creates a sense of discomfort).

When turning assist is enabled, the marker lamps can be used as turning guidance lamps.

<Rice transplanter turning assist monitor guidance display (2)>
In the rice transplanter turning assist control, the marker monitor lamp when turning right is configured to flash the right lamp in the turning direction periodically (on time 500 ms, period 1 second, etc.) from the start to the end of the turning assist.

During auto marker operation (conditions for turning assist), when the planting section rises, the marker monitor lamp does not move in the direction of turning, but lights up in the opposite direction to the direction it is currently in. In other words, when turning left, the marker is out on the left and the lamp is on the left, but when making a back turn, the marker lamp automatically lights up in the opposite direction. This means that although the direction in which the steering wheel is turned to the left when turning is the left, the lamp is on to the right, which makes the worker feel uncomfortable (this is actually a marker lamp and not a turning direction lamp, so the operation is correct but it creates a sense of discomfort).

When turning assist is enabled, the marker lamps can be used as turning guidance lamps.

<Rice transplanter turning assist monitor guidance display (3)>
The rice transplanter turning assist control is configured to display "Turning assist: turning left" during left turning from the start to the end of turning assist.

During auto marker operation (conditions for turning assist), when the planting section rises, the marker monitor lamp does not move in the direction of turning, but lights up in the opposite direction to the direction it is currently in. In other words, when turning left, the marker is out on the left and the lamp is on the left, but when making a back turn, the marker lamp automatically lights up in the opposite direction. This means that although the direction in which the steering wheel is turned to the left when turning is the left, the lamp is on to the right, which makes the worker feel uncomfortable (this is actually a marker lamp and not a turning direction lamp, so the operation is correct but it creates a sense of discomfort).

You can see the current turning direction.

<Rice transplanter turning assist monitor guidance display (4)>
The rice transplanter turning assist control is configured to display "Turning assist: turning right" during right turning from the start to the end of turning assist.

During auto marker operation (conditions for turning assist), when the planting section rises, the marker monitor lamp does not move in the direction of turning, but lights up in the opposite direction to the direction it is currently in. In other words, when turning left, the marker is out on the left and the lamp is on the left, but when making a back turn, the marker lamp automatically lights up in the opposite direction. This means that although the direction in which the steering wheel is turned to the left when turning is the left, the lamp is on to the right, which makes the worker feel uncomfortable (this is actually a marker lamp and not a turning direction lamp, so the operation is correct but it creates a sense of discomfort).

You can see the current turning direction.

<Rice transplanter turning assist monitor display (1)>
During back-turn control using the rice transplanter turning assist control, the monitor will display an interrupt message saying "Please move the main shift lever to the reverse side" from the start of backing up until the end of backing up.

At first, it was difficult for the operator to understand what to do during turning assistance.

Inform workers how to operate the equipment.

<Rice transplanter turning assist monitor display (2)>
During the rice transplanter turning assist control, after the backturn is completed during the backturn control, the monitor will display an interrupt message "Turning assist in progress" from the forward operation to the completion of the turning assist control.

Inform the operator that turning assist control is currently in progress and that the HST and steering operation is different from normal.

<Rice transplanter turning assist monitor display (3)>
When the rice transplanter turning assist control is set to make a U-turn, if the conditions for starting the U-turn control are met (if only the planting part needs to be raised), an interrupt message "Start turning by operating the planting part to raise it while moving forward" is displayed on the monitor.

At first, it is difficult for the operator to understand what operation to perform during turning assistance. In particular, it is difficult to understand the difference between back-turn and U-turn control, as the starting conditions are different.

Inform workers how to operate the equipment.

<Rice transplanter turning assist monitor display (4)>
During U-turn control using rice transplanter turning assist control, the monitor is configured to display an interrupt message "Turning assist in progress" from the start of the U-turn until the completion of turning assist control.

Inform the operator that turning assist control is currently in progress and that the HST and steering operation is different from normal.

<Rice transplanter turning assist monitor display (5)>
If the rice transplanter turning assist control interrupts the turning assist control during backturn control, the message "Turning assist has been canceled" is displayed.

Informs the operator that turning assistance has been canceled.

<Rice transplanter turning assist monitor display (6)>
If the rice transplanter turning assist control is interrupted during U-turn control, the message "Turning assist has been canceled" is displayed.

Informs the operator that turning assistance has been canceled.

The program of the invention related to the present invention is a program for causing a computer to execute all or part of the steps (or processes, operations, actions, etc.) of the driving control method of the invention related to the present invention described above, and is a program that operates in cooperation with a computer.

The recording medium of the invention related to the present invention is a recording medium on which a program is recorded for causing a computer to execute all or part of the steps (or processes, operations, actions, etc.) of the driving control method of the invention related to the present invention described above, and is a computer-readable recording medium in which the read program is used in cooperation with a computer.

Note that "some steps (or processes, operations, actions, etc.)" mentioned above means one or some of those multiple steps.

In addition, the above-mentioned "operation of a step (or process, operation, action, etc.)" means the operation of all or part of the above-mentioned step.

In addition, one mode of use of the program of the invention related to the present invention may be a mode in which it is transmitted through a transmission medium such as the Internet, light, radio waves, or sound waves, read by a computer, and operates in cooperation with the computer.

In addition, recording media include ROM (Read Only Memory) and the like.

In addition, a computer is not limited to pure hardware such as a CPU (Central Processing Unit), but may also include firmware, an OS (Operating System), and even peripheral devices.

As mentioned above, the configuration of the present invention may be realized in either software or hardware.

The work vehicle of the present invention is capable of controlling the turning of the vehicle body, and is useful for use as a work vehicle such as a rice planter.

REFERENCE SIGNS LIST 10 Vehicle body 20 Engine 30 Travel device 31 Front wheel 32 Rear wheel 33 Auxiliary wheel 41 Main transmission mechanism 42 Auxiliary transmission mechanism 43 Rear wheel gear case 44 Steering motor 50 Driving unit 51 Seat 52 Steering handle 53 Main transmission lever 54 Auxiliary transmission lever 55 Straight-line assist lever 56 Assist mode switch 60 Ground leveling device 61 Ground leveling rotor mechanism 62 Ground leveling float mechanism 70 Fertilizer application device 80 Line drawing marker 90 Planting device lifting device 100 Planting device 101 Spare seedling loading platform 200 Control device 210 Rear wheel rotation speed sensor 220 Planting device lifting sensor 300 Positioning system 400 Threshold adjustment device

Claims (1)

A steering member drive device (44) that drives the steering member (52);
A control device (200) for controlling the steering member drive device (44);
Equipped with
A work vehicle in which the control device (200) performs straight-line control when moving a vehicle body (10) straight, performs turning control when turning the vehicle body (10) that has been moving straight, or when stopping the vehicle body (10) that has been moving straight, moving it backward, and turning it after stopping it again, and performs straight-line control after turning when making the turning vehicle body (10) move straight again,
The size of the turning trajectory is determined based on the aircraft travel distance and the aircraft heading,
The timing of returning the steering to make the turning vehicle body (10) go straight again is determined by measuring the vehicle travel distance from the start of the turn until the vehicle heading reaches a predetermined heading, and changing the timing of returning the steering based on the vehicle travel distance;
The control device (200) controls the vehicle speed by regulating the vehicle speed using a first regulation speed and a second regulation speed lower than the first regulation speed in the turning control;
The vehicle speed is restricted by utilizing a second restricted speed at the timing of returning the steering wheel;
When the vehicle body (10) is reversed, the control device (200) regulates the vehicle speed using a third regulation speed not exceeding the second regulation speed;
When the work vehicle is reversed and then stopped again, the steering member (52) is oriented in the turning direction.