JP7722412B2 - Work vehicles - Google Patents

Description

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

There is known an agricultural work vehicle equipped with a GPS device and a teaching path generation means, which generates a teaching path based on position information measured by the GPS device, and which then generates a target path parallel to the teaching path using the teaching path generation means. The agricultural work vehicle then travels autonomously along the target path, and when the operator operates an automatic turning tool, the vehicle automatically turns toward the next target path, and continues to travel autonomously along the next target path after the turning operation is complete (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2008-092818

By the way, the inventor believes that the trend of implementing convenient functions one after another into work vehicles such as rice transplanters will continue to accelerate, taking into consideration the various needs of work vehicle users.

However, the inventors have noticed that conventional work vehicles are not always easy to use when utilizing convenient functions.

More specifically, the inventors have noticed that, for example, when straight-line driving assistance has ended and the vehicle body is being moved for the next straight-line driving assistance, it is not easy to properly acquire the straight-line path reference point.

The present invention takes into consideration the above-mentioned conventional problems and aims to provide a work vehicle that can improve usability.

The first aspect of the present invention is a work vehicle that travels along a straight path,
a controller (110) that performs straight-line assist to make the vehicle body (100) move straight along the straight-line path;
a straight-line assist start instruction member (120) that issues a straight-line assist start instruction to the controller (110) in response to a manual operation by a user;
It is equipped with
When the straight-line driving assist is completed and the vehicle body (100) is being moved for the next straight-line driving assist, the controller (110) repeatedly determines whether or not a straight-line route reference point acquisition condition is satisfied, and when it determines that the straight-line route reference point acquisition condition is satisfied, acquires the position of the vehicle body (100) as a straight-line route reference point and stores the straight-line route reference point, and after storing the straight-line route reference point, starts the straight-line driving assist when a straight-line driving assist start instruction is given,
The controller (110) continues to determine whether the straight-line route reference point acquisition condition is satisfied even after storing the straight-line route reference point, and if it determines that the straight-line route reference point acquisition condition is no longer satisfied without the straight-line assist start instruction being issued, the controller discards the stored straight-line route reference point.
A second aspect of the present invention is the work vehicle of the first aspect of the present invention, wherein after discarding the straight path reference point, the controller (110) does not acquire the straight path reference point again until it determines that a straight path reference point re-acquisition condition is satisfied.
A third aspect of the present invention is the work vehicle according to the second aspect of the present invention, characterized in that the straight path reference point reacquisition condition is a condition relating to the time elapsed since the straight path reference point was discarded.
A fourth aspect of the present invention is the work vehicle according to the second aspect of the present invention, characterized in that the straight path reference point reacquisition condition is a condition related to the steering angle from the point in time when the straight path reference point was discarded.
A fifth aspect of the present invention is the work vehicle according to the first aspect of the present invention, wherein an alert is output to the user as to whether or not the straight path reference point has been stored.
A first invention related to the present invention is a work vehicle that travels along a plurality of parallel linear paths,
a controller (110) that performs straight-line assist to make the vehicle body (100) move straight along the straight-line path;
a straight-line assist start instruction member (120) that issues a straight-line assist start instruction to the controller (110) in response to a manual operation by a user;
It is equipped with
When the straight-line driving assist ends and the vehicle body (100) is being moved for the next straight-line driving assist, the controller (110) acquires the position of the vehicle body (100) as a straight-line driving reference point and stores the straight-line driving reference point when it determines that the straight-line path reference point acquisition condition is satisfied, and after storing the straight-line path reference point, if an instruction to start the straight-line driving assist is given, the work vehicle is characterized in that it starts the straight-line driving assist.

A second invention related to the present invention is a work vehicle of the first invention related to the present invention, characterized in that after the controller (110) stores the straight path reference point, if the straight path assist start command has not been issued before the point at which it is determined that the straight path reference point acquisition condition is not satisfied, the controller (110) discards the stored straight path reference point, but if the straight path assist start command has been issued, the controller does not discard the stored straight path reference point.

A third invention related to the present invention is a work vehicle of the second invention related to the present invention, characterized in that after the controller (110) stores the straight path reference point, if the straight path assist start command has not been issued before the point at which it is determined that the straight path assist start condition is not satisfied, the controller (110) discards the stored straight path reference point, but if the straight path assist start command has been issued, the controller does not discard the stored straight path reference point.

A fourth aspect of the present invention is the work vehicle of the second or third aspect of the present invention, characterized in that after discarding the straight path reference point, the controller (110) does not acquire the straight path reference point again until it determines that a straight path reference point re-acquisition condition is satisfied.

A fifth invention related to the present invention is the work vehicle of the fourth invention related to the present invention, characterized in that the straight path reference point re-acquisition condition is a condition related to the elapsed time from the point in time when the straight path reference point was discarded.

A sixth invention related to the present invention is the work vehicle of the fourth invention related to the present invention, characterized in that the straight path reference point re-acquisition condition is a condition related to the steering angle from the point in time when the straight path reference point is discarded.

A seventh invention related to the present invention is a work vehicle according to any one of the first to third inventions related to the present invention , characterized in that an alert is output to the user as to whether or not the straight path reference point has been stored.

An eighth aspect of the present invention is a fertilizer applicator (220) driven by utilizing the driving force of the rear wheels (210),
This is a work vehicle characterized in that the driving speed of the fertilizer applicator (220) can be adjusted according to the rotation speed of the motor (240) output via a planetary gear mechanism (230).

A ninth aspect of the present invention is a method for detecting a distance to a water surface in a field, comprising:
The input amount of the field material is adjustable according to the field depth calculated based on the distance to the water surface of the field;
The work vehicle is characterized in that the distance sensor (320) is located rearward of the frontmost part of a bumper (310) provided on the front side of the vehicle body when viewed from the side of the vehicle body.

The present invention can improve usability.
The first invention related to the present invention makes it possible to improve usability.

The second invention related to the present invention can improve convenience in addition to the effect of the first invention related to the present invention .

The third invention related to the present invention makes it possible to further improve convenience in addition to the effect of the second invention related to the present invention .

The fourth invention related to the present invention makes it possible to further improve usability in addition to the effects of the second or third invention related to the present invention .

According to the fifth aspect of the present invention , in addition to the effect of the fourth aspect of the present invention , it is possible to simplify the configuration.

According to the sixth aspect of the present invention , in addition to the effect of the fourth aspect of the present invention , it is possible to simplify the configuration.

According to the seventh aspect of the present invention , in addition to the effect of any one of the first to third aspects of the present invention , it is possible to reduce the burden on the worker.

According to an eighth aspect of the present invention , usability can be improved.

The ninth aspect of the present invention makes it possible to improve usability.

1 is a left side view of a rice transplanter according to an embodiment of the present invention; FIG. 10 is an explanatory diagram of the rice transplanter according to the embodiment of the present invention, showing the acquisition of a straight path reference point and the start of a straight-line assist instruction. FIG. 1 is an explanatory diagram of a method for controlling the operation of a work vehicle for a rice transplanter according to an embodiment of the present invention; An explanatory diagram of the vicinity of a straight-line assist sensor of a rice transplanter according to an embodiment of the present invention. FIG. 1 is an explanatory diagram of the vicinity of a fertilizer applicator of a rice transplanter according to an embodiment of the present invention; FIG. 2 is an explanatory diagram of the vicinity of the fertilizer applicator of the rice transplanter according to the embodiment of the present invention (part 2); FIG. 3 is an explanatory diagram of the vicinity of the fertilizer applicator of the rice transplanter according to the embodiment of the present invention (part 3); FIG. 1 is an explanatory diagram (part 1) of the vicinity of the distance sensor of the rice transplanter according to the embodiment of the present invention. FIG. 2 is an explanatory diagram of the vicinity of the distance sensor of the rice transplanter according to the embodiment of the present invention (part 2);

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

As with the following, some components may not be shown in the drawings, or may be shown in perspective or in simplified form.

While explaining the operation of the rice transplanter of this embodiment, we will also explain a work vehicle operation control method related to the present invention, which is realized by the controller 110 and other devices.

The rice transplanter of this embodiment is a specific example of a work vehicle of the present invention that travels along multiple parallel linear paths.

(1) First, the configuration and operation of the rice transplanter of this embodiment will be specifically described with reference to Figures 1 to 4.

Here, Figure 1 is a left side view of a rice transplanter according to an embodiment of the present invention, Figure 2 is an explanatory diagram of the acquisition of a straight path reference point and the instruction to start straight-line assist for a rice transplanter according to an embodiment of the present invention, Figure 3 is an explanatory diagram of a work vehicle operation control method for a rice transplanter according to an embodiment of the present invention, and Figure 4 is an explanatory diagram of the area around the straight-line assist sensor 1006 for a rice transplanter according to an embodiment of the present invention.

The work vehicle operation control method of this embodiment is a control method performed based on a flowchart having steps S1 to S7.

The straight-line assist start instruction member 120 is a member that issues a straight-line assist start instruction to the controller 110, which provides straight-line assistance to move the vehicle body 100 in a straight line along a straight path, in response to manual operation by the user.

In this embodiment, when the straight path reference point acquisition condition is satisfied and the finger lever serving as the straight driving assistance start instruction member 120 is manually raised, straight driving assistance is initiated.

When the straight-line driving assistance ends and the vehicle body 100 is being moved for the next straight-line driving assistance, the controller 110 acquires the position of the vehicle body 100 as the straight-line driving reference point and stores the straight-line driving reference point when it determines that the straight-line path reference point acquisition conditions are satisfied. After storing the straight-line path reference point, if a command to start straight-line driving assistance is given, the controller 110 starts straight-line driving assistance.

Turning to transition from a straight path to another straight path is typically performed manually, but it may also be performed automatically by using a method for aiming at a predetermined target straight path. In either case, when the vehicle body 100 is being turned, the straight path reference point P is automatically acquired and stored, and a straight path R passing through the straight path reference point P is set as a straight path parallel to the straight path immediately before the turn.

When the vehicle body 100 is turning in the normal sense by performing a turning movement that follows an arc-shaped turning path, the position of the vehicle body 100 may be acquired as a straight-line path reference point. Conversely, after such turning movement is completed, the position of the vehicle body 100 may also be acquired as a straight-line path reference point. More specifically, after turning movement is completed, depending on the user's steering skill level, at a point between the timing when so-called row alignment is performed to adjust the spacing between adjacent seedling planting rows and the timing when the planting rod is rotated and straight-line movement for planting begins, the steering angle often stably coincides with an angle of approximately zero, which corresponds to a straight-line steering position, satisfying the straight-line path reference point acquisition condition, and the position of the vehicle body 100 may be acquired as a straight-line path reference point.

In this embodiment, the straight path reference point P of an agricultural machine such as a rice transplanter equipped with an automatic steering function using straight-line assistance is acquired when the straight path reference point acquisition conditions defined by the following (Requirement 1) to (Requirement 9) are fully satisfied.

(Requirement 1) The first and second reference points for determining the direction of multiple parallel straight-line paths, so-called points A and B, are acquired in advance prior to straight-line driving assistance.

(Requirement 2) The leveling rotor 1001 is turned on at a height of less than 450 mm.

(Requirement 3) GPS (Global Positioning System) radio waves can be acquired by the GPS device 1002.

(Requirement 4) The deviation in vehicle orientation, which is the deviation between the vehicle orientation of the turning vehicle body 100 and the straight-ahead orientation given by the direction of the straight-line path, is 3 degrees or less.

(Requirement 5) The inclination of the vehicle body 100 from the horizontal plane, which is important for understanding the vehicle body posture, is less than 10 degrees.

(Requirement 6) The vehicle speed of the vehicle body 100 is not the so-called road speed.

(Requirement 7) The trunnion angle of the HST (Hydro Static Transmission) device 1003 is not the angle on the reverse side.

(Requirement 8) The GPS vehicle speed measured by the GPS device 1002 is greater than or equal to 0.5 kilometers per hour, i.e., greater than or equal to approximately 0.14 meters per second.

(Requirement 9) The steering handle angle of the steering device 1004 that provides the steering angle is greater than or equal to -20 degrees and less than or equal to +20 degrees.

Therefore, obtaining the straight-line path reference point P is separate from the start of straight-line driving assistance.

For example, in the steering straight-line determination according to the above-mentioned (Requirement 9), an embodiment is conceivable in which the instantaneous value of the steering angle is not used, but rather the average steering angle for an average movement over 500 milliseconds is used. Even if small steering wheel movements are performed to transition to an adjacent planting row and the steering angle deviates from the straight-line angle range for a short period of time, the straight-line path reference point P can be obtained without any problems, so the start of straight-line assistance is unlikely to be hindered.

The above-mentioned value of 500 milliseconds, which indicates the average travel time, can be rewritten to a value between 100 and 3000 milliseconds, and the above-mentioned value of 20 degrees, which indicates the steering wheel angle range, can be rewritten to a value between 10 and 100 degrees. The straight-line assist sensor 1006, which detects the rotation angle of the steering wheel shaft 1005 driven by the steering motor when straight-line assist begins, has a detection range corresponding to a steering angle range of -150 degrees to 150 degrees, and a resolution of approximately 0.3 degrees.

For example, the following (Requirement 10) may be added to the straight-line path reference point acquisition conditions.

(Requirement 10) The steering angular velocity is 90 degrees per second or less.

If the deviation in vehicle orientation is less than 3 degrees and the straight-line steering state continues, the straight-line path reference point acquisition conditions defined by (Requirement 1) to (Requirement 9) are often satisfied, and the stored straight-line path reference point P is maintained. However, in such cases, if the driving distance increases without a straight-line assist start command being issued, the straight-line assist start position is likely to deviate significantly from the straight-line path R passing through the straight-line path reference point P, making it likely that the vehicle 100 will meander significantly toward the straight-line path R. By adding (Requirement 10), when a rapid steering operation for alignment is performed at a large steering angular velocity, the straight-line path reference point P is appropriately discarded, thereby preventing meandering.

An alert will be output to the user regarding whether or not the straight path reference point has been memorized.

Such alerts are issued using the on or off state of an alert lamp. Events such as the occurrence of lateral deviation exceeding an acceptable level, as described below, may be issued using a general-purpose alert lamp that repeatedly flashes on and off at short intervals, or may be issued using the on state of a dedicated lamp.

The user will be notified by an alert whether or not a straight-line route reference point has been stored, so a command to start straight-line assistance will rarely be issued even if a straight-line route reference point has not been stored.

However, if a straight-line assist start instruction is given due to user inattention or other reasons, even though the straight-line path reference point has not been stored, it is possible that the straight-line assist start instruction will not be accepted and straight-line assist will not begin. It goes without saying that there are also possible situations in which the straight-line assist start instruction will be provisionally accepted, with the start of straight-line assist itself being put on hold, and straight-line assist will begin immediately once the straight-line path reference point is acquired.

After storing the straight path reference points, if a straight driving assist start instruction is not given before the controller 110 determines that the straight path reference point acquisition condition is not satisfied, the controller 110 discards the stored straight path reference points. However, if a straight driving assist start instruction is given, the controller 110 does not discard the stored straight path reference points.

For example, if a command to start straight-line assistance is not issued after the straight-line path reference point P is stored and before it is determined that the straight-line path reference point acquisition conditions specified by (Requirement 1) to (Requirement 10) are not satisfied, the stored straight-line path reference point P may be discarded.

After storing the straight path reference points, if a straight driving assist start instruction is not given before the controller 110 determines that the straight driving assist start conditions are not satisfied, the controller 110 will discard the stored straight path reference points. However, if a straight driving assist start instruction is given, the controller 110 does not need to discard the stored straight path reference points.

For example, if a straight driving assist start condition is adopted that requires that the lateral deviation from the straight path R does not exceed 10 centimeters, and even in a straight driving assist standby state in which the straight path reference point acquisition condition is satisfied after the straight path reference point P is stored, if a straight driving assist start command is not issued before it is determined that the lateral deviation calculated based on the CAN (Controller Area Network) data received from the straight driving assist unit exceeds 10 centimeters, the stored straight path reference point P can be discarded.

Of course, discarding the straight-line path reference point P will result in refusal to accept a command to start straight-line assistance, thereby preventing the start of inappropriate straight-line assistance.

Once the command to start straight-line assistance is issued, it can be said that the provisionally acquired straight-line route reference point is officially adopted.

Furthermore, after discarding a straight path reference point, the controller 110 does not need to reacquire the straight path reference point until it determines that the straight path reference point reacquisition condition is satisfied.

Even immediately after the straight path reference point P is discarded, the straight path reference point acquisition conditions are often satisfied, but the acquisition of a new straight path reference point is suppressed in consideration of the possibility that the user, upon noticing an alert or other indication that a lateral deviation exceeding the allowable level has occurred, may perform appropriate steering operation.

The straight path reference point reacquisition condition is a condition regarding the amount of time that has elapsed since the straight path reference point was discarded.

For example, after the amount of lateral deviation exceeds the allowable level and straight path reference point P is discarded, a new straight path reference point may not be acquired until an observation time of approximately one second has elapsed. The acquisition of a new straight path reference point is suppressed until the amount of lateral deviation becomes small enough that ideal straight-line driving assistance is expected to begin.

The straight path reference point reacquisition condition may also be a condition regarding the steering angle from the point at which the straight path reference point was discarded.

For example, after the amount of lateral deviation exceeds the allowable level and straight path reference point P is discarded, a new straight path reference point may not be acquired until the steering angle of the steering device 1004 that provides the steering angle falls within an angle range of -1 degree or more and +1 degree or less. When a steering operation that meets a steering angle requirement that is stricter than (Requirement 9) is performed so as to cross the center position of the steering wheel, a new straight path reference point is acquired smoothly regardless of the passage of the observation time described above, and ideal straight-line driving assistance can be expected to begin.

(2) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, primarily with reference to Figures 5 to 7.

Here, Figures 5 to 7 are explanatory diagrams (parts 1 to 3) of the vicinity of the fertilizer applicator 220 of a rice transplanter according to an embodiment of the present invention.

Figure 5 illustrates the output direction of the rear wheel rotary shaft when viewed from the front, Figure 6 illustrates the output direction of the rear wheel rotary shaft when viewed from the side, and Figure 7 illustrates the configuration of a so-called electric HMT (Hydro Mechanical Transmission) fertilizer applicator.

The configuration of the fertilizer applicator 220, which utilizes an HMT mechanism, in which the rear wheel rotation output passes through a universal joint 2002, an electric unit 2003, and a roller clutch 2007 and is output as fertilizer output to the fertilizer drive shaft, is described in more detail below.

The driving speed of the fertilizer applicator 220, which is driven by the driving force of the rear wheels 210, can be adjusted according to the rotation speed of the motor 240 output via the planetary gear mechanism 230.

In a rice transplanter with a fertilizer applicator, one possible configuration is to obtain rotational output from rear wheels 210 to drive fertilizer applicator 220, which is an electric fertilizer applicator, and adjust the fertilizer applicator drive speed according to the motor rotation speed using a mechanism that utilizes planetary gear 2006 and motor 240. By obtaining torque from the rotation of the rear wheels 210, delays in starting the machine due to the large starting torque required by fertilizer applicator 220 are suppressed, and a configuration is realized that does not require the large torque of motor 240.

In the above-described configuration, a configuration is conceivable in which fertilization drive output is directed upward from the rear wheel case 2001, also known as the rear wheel rear case.

In the above-described configuration, a unit configuration is possible in which the output from the rear wheel case 2001 is transmitted from the planetary gear 2006 to the ring gear 2004 and then output to the fertilizer drive shaft.

In the above-described configuration, the sun gear 2005 may be rotated by the motor 240. The motor is normally stopped, but when the vehicle speed increases and the amount of fertilizer applied decreases, the motor 240 rotates at a higher speed.

In the above-described configuration, it is conceivable that the rotation speed of the fertilizer drive shaft is at its maximum when the motor 240 is stopped, and the maximum amount of fertilizer applied is 80 kg/10 a.

In the above-described configuration, a configuration using a sensor that detects the rear wheel rotation speed of the rear wheels 210 and a sensor that detects the output rotation speed of the fertilizer output to the fertilizer drive shaft is conceivable.

In the above-described configuration, it is possible to configure the motor 240 to be controlled to adjust the rotational speed so that the output rotational speed to the fertilizer drive shaft is zero when fertilization is not being performed.

In the above-described configuration, when the amount of fertilizer to be applied is set between zero and the maximum amount, one possible configuration is to adjust the amount of fertilizer application by controlling the ratio of the rear wheel rotation speed of the rear wheels 210 to the rotation speed of the fertilizer drive shaft through the rotation of the motor 240. Any amount of fertilizer application between zero and 80 kg can be set, and when spreading fertilizer at a rate of 40 kg/10 a, the motor is controlled at a rotation speed ratio of 2:1.

In the above-described configuration, it is possible to perform so-called electric trial feeding by rotating the motor 240 in the opposite direction to the fertilizing rotation direction.

In the above-described configuration, when the vehicle is stopped with the parking brake pedal locked and the engine is on but the rear wheels 210 are not rotating, pressing the electric trial payout button may cause the motor 240 to rotate in reverse.

In the above-described configuration, for rice transplanters equipped with a GNSS (Global Navigation Satellite System) antenna, a possible configuration is to correct the ratio between the rotational speed of the rear wheels 210 and the rotational speed of the fertilizer application drive shaft according to the slip ratio calculated from the antenna vehicle speed and the rear wheel rotational speed. By correcting based on the slip ratio, the adverse effects of inaccurate fertilizer application due to wheel wear, etc., can be reduced.

(3) Next, the configuration and operation of the rice transplanter of this embodiment will be explained in more detail, primarily with reference to Figures 8 and 9.

Here, Figures 8 and 9 are explanatory diagrams (parts 1 and 2) of the vicinity of the distance sensor 320 of a rice transplanter according to an embodiment of the present invention.

Figure 8 shows the location of the distance sensors in a side view, and Figure 9 shows the location of the distance sensors in a front view.

The location of the distance sensor 320 of the variable fertilizer rice transplanter is explained in more detail below.

The amount of field materials added can be adjusted according to the field depth calculated based on the distance to the water surface in the field.

It is possible to configure a rice transplanter that can calculate the field depth and change the amount of field materials input by measuring the distance from the position of the distance sensor 320, which is an ultrasonic sensor, to the water surface in the field.

The distance sensor 320, which measures the distance to the water surface in the field, is located rearward of the front of the bumper 310 attached to the front side of the vehicle body when viewed from the side of the vehicle body.

In the above-described configuration, it is possible to position the distance sensor 320 toward the rear of the vehicle body 100, relative to the front of the bumper 310 at the front of the rice transplanter. By positioning the distance sensor 320 on the inside of the bumper 310, it is possible to protect the distance sensor 320.

In the above-described configuration, it is conceivable to position the distance sensor 320 in a position that overlaps with the bumper 310 on the front side of the rice transplanter when viewed from the front of the vehicle body.

In the above-described configuration, it is conceivable to position the distance sensor 320 in a position that overlaps with the bumper 310 on the front side of the rice transplanter when viewed from the side of the vehicle body.

In the above-described configuration, a configuration with antenna specifications is possible in which the vehicle body roll angle of the vehicle body 100 is measured and corrected using GNSS and IMU (Inertial Measurement Unit) antenna sensors.

In the above-described configuration, a model specification configuration with an antenna is possible in which the vehicle pitch angle of the vehicle body 100 is measured and corrected using GNSS and IMU antenna sensors.

In the above-described configuration, a model specification configuration without an antenna is conceivable in which a horizontal sensor located on the main frame of the machine measures and corrects the vehicle pitch angle of the vehicle body 100.

In the above-mentioned configuration, it is possible to position the horizontal sensor at the center position in the left-right direction of the vehicle, in the area between the front and rear wheel axes when viewed from the side of the water.

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

Furthermore, the recording medium of the invention related to the present invention is a recording medium on which a program is recorded that causes a computer to execute all or some of the steps (or processes, operations, actions, etc.) of the work vehicle operation 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 the above phrase "some steps (or processes, operations, actions, etc.)" refers to one or several steps among those multiple steps.

Furthermore, the above-mentioned "operations of steps (or processes, actions, acts, etc.)" refer to the operations of all or part of the above-mentioned steps.

Furthermore, one form of use of the inventive program related to this invention may be a form 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).

Furthermore, 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 implemented in either software or hardware.

The work vehicle of the present invention can improve usability and is useful for use as a work vehicle such as a rice transplanter.

100 Body 110 Controller 120 Straight-line assist start instruction member 210 Rear wheel 220 Fertilizer applicator 230 Planetary gear mechanism 240 Motor 310 Bumper 320 Distance sensor 1001 Ground leveling rotor 1002 GPS device 1003 HST device 1004 Steering device 1005 Steering handle shaft 1006 Straight-line assist sensor 2001 Rear wheel case 2002 Universal joint 2003 Electric unit 2004 Ring gear 2005 Sun gear 2006 Planetary gear 2007 Roller clutch P Straight-line path reference point R Straight-line path

Claims (5)

A work vehicle that travels along a straight path,
a controller (110) that performs straight-line assist to make the vehicle body (100) move straight along the straight-line path;
a straight-line assist start instruction member (120) that issues a straight-line assist start instruction to the controller (110) in response to a manual operation by a user;
It is equipped with
When the straight-line driving assist is completed and the vehicle body (100) is being moved for the next straight-line driving assist, the controller (110) repeatedly determines whether or not a straight-line route reference point acquisition condition is satisfied, and when it determines that the straight-line route reference point acquisition condition is satisfied, acquires the position of the vehicle body (100) as a straight-line route reference point and stores the straight-line route reference point, and after storing the straight-line route reference point, starts the straight-line driving assist when a straight-line driving assist start instruction is given ,
The controller (110) continues to determine whether the straight-line route reference point acquisition condition is satisfied even after storing the straight-line route reference point, and if it determines that the straight-line route reference point acquisition condition is no longer satisfied without the straight-line assist start instruction being issued, the controller discards the stored straight-line route reference point . 2. The work vehicle according to claim 1, wherein after discarding the straight path reference point, the controller ( 110 ) does not acquire the straight path reference point again until it determines that a straight path reference point reacquisition condition is satisfied. 3. The work vehicle according to claim 2 , wherein the straight path reference point reacquisition condition is a condition relating to the amount of time that has elapsed since the straight path reference point was discarded. 3. The work vehicle according to claim 2 , wherein the straight path reference point reacquisition condition is a condition related to a steering angle from a point in time when the straight path reference point is discarded. The work vehicle according to claim 1 , wherein an alert is output to the user regarding whether or not the straight path reference point has been stored.