Work vehicles

Abstract

To disclose that an inventor has been aware that it is not easy to appropriately obtain a straight route reference point when straight advancing assist is over and a vehicle body is being moved for a next straight advancing assist.SOLUTION: A rice planting machine includes: a controller 110 which performs straight advancing assist for advancing a vehicle body 100 straight along a straight route; and a straight advancing assist start instruction member 120 for giving a straight advancing start instruction to the controller 110 in accordance with a user's manual operation. When the straight advancing is over and the vehicle body 100 is being moved for next straight advancing assist, the controller 110 obtains a location of the vehicle body 100 as a straight route reference point and stores the straight route reference point when it is determined that a straight route reference point acquisition condition is satisfied, and when the straight advancing assist start instruction is given after the straight route reference point is stored, starts the straight advancing assist.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work vehicle such as a rice transplanter. [Background technology]

[0002] An agricultural work vehicle is known that is equipped with a GPS device and a teaching path generation means, and generates a teaching path using the teaching path generation means based on position information measured by the GPS device.The teaching path generation means then generates a target path parallel to the teaching path, and the agricultural work vehicle runs autonomously along the target path.In this agricultural work vehicle, an automatic turning operating tool is operated by the operator, causing the vehicle to automatically turn toward the next target path, and after the turning operation is completed, the vehicle continues to run autonomously along the next target path (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-092818 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the inventor believes that the trend of implementing convenient functions one after another in work vehicles such as rice transplanters will continue to accelerate, taking into consideration the various needs of work vehicle users.

[0005] However, the inventors have noticed that conventional work vehicles are not necessarily easy to use when using convenient functions.

[0006] 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.

[0007] SUMMARY OF THE INVENTION In consideration of the above-mentioned problems inherent in the prior art, the present invention has an object to provide a work vehicle that can improve usability. [Means for solving the problem]

[0008] 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 cause the vehicle body (100) to travel 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 path reference point acquisition condition is satisfied, and when it determines that the straight-line path reference point acquisition condition is satisfied, acquires the position of the vehicle body (100) as a straight-line path reference point and stores the straight-line path reference point, and after storing the straight-line path 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 path reference point acquisition condition is satisfied even after storing the straight path reference point, and if it determines that the straight path reference point acquisition condition is no longer satisfied without the straight-line assist start instruction being issued, the controller discards the stored straight path reference point. The 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, wherein 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. First invention related to the present invention is a work vehicle that travels along a plurality of parallel straight-line paths, a controller (110) that performs straight-line assist to cause the vehicle body (100) to travel 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.

[0009] Second invention related to the present inventionthe controller (110) stores the straight path reference point, and if the straight path assist start instruction is not given before the time when 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 instruction is given, the controller (110) does not discard the stored straight path reference point. First invention related to the present invention It is a work vehicle.

[0010] Third invention related to the present invention The controller (110) stores the straight path reference point, and if the straight path assist start command is not issued before the time when 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 is issued, the controller (110) does not discard the stored straight path reference point. Second invention related to the present invention It is a work vehicle.

[0011] The fourth invention related to the present invention 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 after discarding the straight path reference point. Second or third invention related to the present invention It is a work vehicle.

[0012] Fifth Invention Related to the Present Invention The straight path reference point reacquisition condition is a condition regarding the elapsed time from the point in time when the straight path reference point is discarded. The fourth invention related to the present invention It is a work vehicle.

[0013] The sixth invention related to the present invention The straight path reference point reacquisition condition is a condition regarding a steering angle from a point in time when the straight path reference point is discarded. The fourth invention related to the present invention It is a work vehicle.

[0014] Seventh Invention Related to the Present Invention an alert is output to the user as to whether the straight path reference point has been stored or not. Any of the first to third inventions related to the present invention It is a work vehicle.

[0015] Eighth invention related to the present invention The fertilizer applicator (220) is driven by utilizing the driving force of the rear wheels (210), The working vehicle is characterized in that the driving speed of the fertilizer applicator (220) can be adjusted according to the rotation speed of a motor (240) outputted via a planetary gear mechanism (230).

[0016] Ninth invention related to the present invention is provided with a distance sensor (320) for measuring the distance to the water surface in the field; 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 forefront of a bumper (310) provided on the front side of the vehicle body in a side view of the vehicle body. [Effects of the Invention]

[0017] The present invention can improve usability. First invention related to the present invention This makes it possible to improve usability.

[0018] Second invention related to the present invention Therefore, First invention related to the present invention In addition to the above effect, it is possible to improve convenience.

[0019] Third invention related to the present invention Therefore, Second invention related to the present invention In addition to the above effects, it is possible to further improve convenience.

[0020] The fourth invention related to the present invention Therefore, Second or third invention related to the present invention In addition to the above effects, it is possible to further improve usability.

[0021] Fifth Invention Related to the Present Invention Therefore, The fourth invention related to the present invention In addition to the above effect, the configuration can be simplified.

[0022] The sixth invention related to the present invention Therefore, The fourth invention related to the present inventionIn addition to the above effect, the configuration can be simplified.

[0023] Seventh Invention Related to the Present Invention Therefore, Any of the first to third inventions related to the present invention In addition to the above effect, it is possible to reduce the burden on the worker.

[0024] Eighth invention related to the present invention This makes it possible to improve usability.

[0025] Ninth invention related to the present invention This makes it possible to improve usability. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a left side view of a rice transplanter according to an embodiment of the present invention; [Figure 2] 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. [Figure 3] 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; [Figure 4] An explanatory diagram of the vicinity of a straight-line assist sensor of a rice transplanter according to an embodiment of the present invention. [Figure 5] 1 is an explanatory diagram of the vicinity of a fertilizer applicator of a rice transplanter according to an embodiment of the present invention (part 1); [Figure 6] 1 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) [Figure 7] 1 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) [Figure 8] 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. [Figure 9] 1 is an explanatory diagram (part 2) of the vicinity of the distance sensor of the rice transplanter according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings.

[0028] Similarly, some components may not be shown in the drawings, or may be shown in perspective or in simplified form.

[0029] While explaining the operation of the rice transplanter of this embodiment, a work vehicle operation control method of an invention related to the present invention, which is realized by the controller 110 and the like, will also be explained.

[0030] The rice transplanter of this embodiment is a specific example of a work vehicle of the present invention that travels along a plurality of parallel linear paths.

[0031] (1) First, the configuration and operation of the rice transplanter of this embodiment will be specifically described with reference to FIGS. 1 to 4.

[0032] 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 start of a straight-line assist command 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 vicinity of the straight-line assist sensor 1006 for a rice transplanter according to an embodiment of the present invention.

[0033] The work vehicle operation control method of this embodiment is a control method carried out based on a flowchart having steps S1 to S7.

[0034] The straight-line assist start instruction member 120 is a member that issues a straight-line assist start instruction to the controller 110, which performs straight-line assist to make the vehicle body 100 travel straight along a straight path, in response to a manual operation by the user.

[0035] In this embodiment, when the straight path reference point acquisition condition is satisfied, the straight driving assistance is started when the finger lever serving as the straight driving assistance start instruction member 120 is manually operated to raise the lever.

[0036] When the straight-line assist is completed and the vehicle body 100 is being moved for the next straight-line assist, the controller 110, upon determining that the straight-line route reference point acquisition condition is satisfied, acquires the position of the vehicle body 100 as the straight-line route reference point and stores the straight-line route reference point, and after storing the straight-line route reference point, if an instruction to start straight-line assist is given, starts the straight-line assist.

[0037] Turning to transition from a straight path to a straight path is typically performed manually, but may also be performed automatically by using a method of aiming at a predetermined target straight path, etc. In any case, when the vehicle body 100 is turned, if the straight path reference point P is automatically acquired and stored, 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.

[0038] 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, while on the other hand, after such turning movement is completed, the position of the vehicle body 100 may 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 may stably coincide with an angle of approximately zero, which corresponds to a straight-line steering position, and the straight-line path reference point acquisition condition may often be satisfied, and the position of the vehicle body 100 may be acquired as a straight-line path reference point.

[0039] In this embodiment, the straight path reference point P of an agricultural machine such as a rice transplanter that is equipped with an automatic steering function using straight-line assist is acquired when the straight path reference point acquisition conditions specified by the following (Requirement 1) to (Requirement 9) are fully satisfied.

[0040] (Requirement 1) First and second reference points for determining the directions of a plurality of parallel straight-line paths, so-called points A and B, are acquired in advance prior to straight-line driving assistance.

[0041] (Claim 2) The ground leveling rotor 1001 is turned on at a height of less than 450 millimeters.

[0042] (Requirement 3) GPS (Global Positioning System) radio waves can be acquired by the GPS device 1002.

[0043] (Requirement 4) The deviation in vehicle body orientation, which is the deviation between the vehicle body orientation of the turning vehicle body 100 and the straight ahead orientation given by the direction of the straight path, is 3 degrees or less.

[0044] (Requirement 5) The tilt of the vehicle body 100 from the horizontal plane, which is important for grasping the vehicle body posture, is less than 10 degrees.

[0045] (Requirement 6) The vehicle speed of the vehicle body 100 is not a so-called road speed.

[0046] (Requirement 7) The trunnion angle of the HST (Hydro Static Transmission) device 1003 is not an angle on the reverse side.

[0047] (Requirement 8) The GPS vehicle speed measured by the GPS device 1002 is 0.5 kilometers per hour or greater, that is, approximately 0.14 meters per second or greater.

[0048] (Requirement 9) The steering wheel angle of the steering device 1004 that provides the steering angle is equal to or greater than -20 degrees and equal to or less than +20 degrees.

[0049] Therefore, the acquisition of the straight path reference point P is separated from the start of the straight driving assistance.

[0050] For example, in the steering straightness determination according to the above-mentioned (Requirement 9), an embodiment is possible in which the average steering angle for an average movement of 500 milliseconds is used instead of the instantaneous value of the steering angle. Even if small steering operations are performed to move to an adjacent planting row and the steering angle deviates from the straight-ahead angle range for a short period of time, the straight-ahead path reference point P is acquired without any problems, so the start of straight-ahead assistance is unlikely to be hindered.

[0051] The above-mentioned value of 500 milliseconds, which gives the average travel time, can be rewritten to a value between 100 and 3000 milliseconds, and the above-mentioned value of 20 degrees, which gives 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.

[0052] For example, the following (Requirement 10) may be added to the straight path reference point acquisition conditions.

[0053] (Requirement 10) The steering angular velocity is 90 degrees per second or less.

[0054] If the deviation in vehicle body orientation is less than 3 degrees and the straight-ahead steering state continues, the straight-ahead route reference point acquisition conditions defined by (Requirement 1) to (Requirement 9) are often satisfied, and the stored straight-ahead route reference point P is maintained. However, in such a case, if the travel distance increases without a straight-ahead assist start command being issued, the straight-ahead assist start position is likely to deviate significantly from the straight-ahead route R passing through the straight-ahead route reference point P, which makes it likely that the vehicle body 100 will meander significantly as it heads toward the straight-ahead route R. By adding (Requirement 10), when a rapid steering operation for positioning is performed at a large steering angular velocity, the straight-ahead route reference point P is appropriately discarded, and the occurrence of meandering is suppressed.

[0055] An alert is output to the user as to whether or not the straight path reference point has been stored.

[0056] Such an alert is issued by utilizing the on or off state of an alert lamp, etc. An event such as the occurrence of a lateral deviation amount exceeding an allowable level, which will be described later, may be issued by utilizing a general-purpose alert lamp that repeatedly flashes on and off at short intervals, or by utilizing the on state of a dedicated lamp.

[0057] The user can recognize from the alert whether or not the straight path reference point has been stored, so that the straight driving assist start instruction is rarely issued even if the straight path reference point has not been stored.

[0058] However, if a straight-line assist start instruction is given due to the user's carelessness or other reasons, even though the straight-line route reference point is not stored, it is possible that the straight-line assist start instruction will not be accepted and straight-line assist will not be started, or that 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 be started immediately once the straight-line route reference point is acquired.

[0059] 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, but if a straight driving assist start instruction is given, the controller 110 does not discard the stored straight path reference points.

[0060] For example, if a straight-line path reference point P is stored and then a straight-line assist start instruction is not issued 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.

[0061] After storing the straight path reference point, if a straight path assist start instruction is not given before the controller 110 determines that the straight path assist start condition is not satisfied, the controller 110 discards the stored straight path reference point. However, if a straight path assist start instruction is given, the controller 110 does not have to discard the stored straight path reference point.

[0062] For example, a straight-line assist start condition is adopted that requires that the lateral deviation from the straight-line path R does not exceed 10 centimeters, and even in a straight-line assist standby state in which the straight-line path reference point acquisition condition is satisfied after the straight-line path reference point P is stored, if a straight-line assist start instruction is not issued before the point in time when it is determined that the lateral deviation calculated based on the CAN (Controller Area Network) data received from the straight-line assist unit exceeds 10 centimeters, the stored straight-line path reference point P can be discarded.

[0063] Of course, when the straight path reference point P is discarded, the acceptance of the straight driving assistance start instruction is rejected, so the start of inappropriate straight driving assistance is suppressed.

[0064] It can be said that the straight-line route reference point that was provisionally acquired is officially adopted when the straight-line assist start command is issued.

[0065] Furthermore, after discarding the straight path reference point, the controller 110 may not acquire the straight path reference point again until it determines that the straight path reference point reacquisition condition is satisfied.

[0066] 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, having recognized the occurrence of a lateral deviation exceeding an allowable level through an alert or the like, will perform appropriate steering operation.

[0067] The straight path reference point reacquisition condition is a condition regarding the time elapsed since the straight path reference point was discarded.

[0068] 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 and the start of ideal straight driving assistance is expected.

[0069] The straight path reference point reacquisition condition may be a condition related to the steering angle from the point in time when the straight path reference point was discarded.

[0070] For example, after the amount of lateral deviation exceeds an allowable level and straight path reference point P is discarded, a new straight path reference point may not be acquired until the steering wheel angle of 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 in response to 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 smoothly acquired regardless of the passage of the above-mentioned observation time, and ideal straight driving assistance can be expected to begin.

[0071] (2) Next, the configuration and operation of the rice transplanter of this embodiment will be described in more detail, mainly with reference to FIGS. 5 to 7.

[0072] 5 to 7 are explanatory views (parts 1 to 3) of the vicinity of the fertilizer applicator 220 of the rice transplanter according to the embodiment of the present invention.

[0073] 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.

[0074] The configuration of the fertilizer applicator 220, which utilizes an HMT mechanism, in which the rear wheel rotation output is passed through a universal joint 2002, an electric unit 2003, and a roller clutch 2007 and extracted as fertilization output to the fertilization drive shaft, is described in more detail below.

[0075] The driving speed of the fertilizer applicator 220 , which is driven by utilizing 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 .

[0076] A possible configuration for a rice transplanter with a fertilizer applicator is to obtain rotational output from rear wheels 210 to drive fertilizer applicator 220, which is an electric fertilizer applicator, and to adjust the fertilizer applicator drive speed according to the motor rotation speed by a mechanism that uses planetary gear 2006 and motor 240. By obtaining torque from the rear wheel rotation of rear wheels 210, delays in starting the machine due to the large starting torque required by fertilizer applicator 220 are suppressed, and a configuration that does not require the large torque of motor 240 is realized.

[0077] In the above-described configuration, a configuration is conceivable in which fertilization drive output is directed upward from the rear wheel case 2001, also called the rear wheel rear case.

[0078] In the above-described configuration, a configuration using a unit that transmits the output from the rear wheel case 2001 through the planetary gear 2006 to the ring gear 2004 and outputs it to the fertilizer drive shaft is conceivable.

[0079] 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 is increased and the amount of fertilizer applied is reduced, the motor 240 rotates at a higher speed.

[0080] In the above-described configuration, a configuration is conceivable in which the rotation speed of the fertilizer application drive shaft is maximum when the motor 240 is stopped, and the amount of fertilizer application is maximum at 80 kg / 10 a.

[0081] 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.

[0082] In the above-described configuration, a configuration may be considered in which, when fertilization is not being performed, the rotation speed of the motor 240 is controlled so that the number of rotations output to the fertilization drive shaft becomes zero.

[0083] In the above-described configuration, when the amount of fertilizer to be applied is set between zero and the maximum amount, a possible configuration is to adjust the amount of fertilizer application by controlling the ratio between the rotation speed of the rear wheels 210 and the rotation speed of the fertilizer application drive shaft through the rotation of the motor 240. Any amount of fertilizer application between zero and 80 kg can be set, and when fertilizer is spread at a rate of 40 kg / 10 a, the motor is controlled at a rotation speed ratio of 2:1.

[0084] In the above-described configuration, a configuration is conceivable in which so-called electric trial feeding is performed by rotating the motor 240 in a rotation direction opposite to the rotation direction for fertilization.

[0085] 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, a configuration is conceivable in which, when the electric trial payout button is pressed, the motor 240 is rotated in reverse.

[0086] In the above-mentioned configuration, in a rice transplanter equipped with a GNSS (Global Navigation Satellite System) antenna, a configuration is possible in which the ratio between the rotation speed of the rear wheels 210 and the rotation speed of the fertilizer application drive shaft is corrected according to the slip ratio calculated from the antenna vehicle speed and the rear wheel rotation speed. By correcting based on the slip ratio, the adverse effects of inaccurate fertilizer application due to wheel wear and tear can be reduced.

[0087] (3) Next, the configuration and operation of the rice transplanter of this embodiment will be described more specifically, mainly with reference to FIGS.

[0088] 8 and 9 are explanatory diagrams (parts 1 and 2) of the vicinity of the distance sensor 320 of the rice transplanter according to the embodiment of the present invention.

[0089] FIG. 8 illustrates the locations of the distance sensors in a side view, and FIG. 9 illustrates the locations of the distance sensors in a front view.

[0090] The position of the distance sensor 320 of the variable fertilizer rice transplanter will be explained in more detail as follows.

[0091] The amount of field material input can be adjusted according to the field depth calculated based on the distance to the water surface in the field.

[0092] A rice transplanter can be configured to calculate the field depth by measuring the distance from the position of distance sensor 320, which is an ultrasonic sensor, to the water surface in the field, and change the amount of field materials input.

[0093] Distance sensor 320, which measures the distance to the water surface in the field, is located rearward of the forefront of bumper 310 provided on the front side of the vehicle body when viewed from the side of the vehicle body.

[0094] In the above-described configuration, it is possible to arrange the distance sensor 320 on the rear side of the vehicle body 100, compared to the front of the bumper 310 on the front side of the rice transplanter. By arranging the distance sensor 320 on the inside of the bumper 310, the distance sensor 320 can be protected.

[0095] In the above-described configuration, it is possible to arrange 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.

[0096] In the above-described configuration, it is possible to arrange 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.

[0097] In the above-described configuration, a configuration with a model specification including an antenna may be considered in which the vehicle body roll angle of the vehicle body 100 is measured and corrected using antenna sensors of the GNSS and IMU (Inertial Measurement Unit).

[0098] In the above-described configuration, a configuration with a model specification including an antenna may be considered in which the vehicle pitch angle of the vehicle body 100 is measured and corrected using the GNSS and IMU antenna sensors.

[0099] In the above-described configuration, a configuration of a model specification without an antenna is conceivable in which the vehicle pitch angle of the vehicle body 100 is measured and corrected using a horizontal sensor disposed on the main frame of the vehicle.

[0100] In the above-described configuration, the horizontal sensor may be arranged at a central position in the left-right direction of the vehicle in the range between the front wheel shaft and the rear wheel shaft when viewed from the side of the water.

[0101] 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 and 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.

[0102] Furthermore, 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 some of the operations of all or some of the steps (or processes, operations and 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.

[0103] It should be noted that the above-mentioned "some steps (or processes, operations, actions, etc.)" means one or some steps among the plurality of steps.

[0104] Furthermore, the above-mentioned "operations of steps (or processes, operations, actions, etc.)" means the operations of all or part of the above-mentioned steps.

[0105] Furthermore, one form of use of the inventive program related to the present 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.

[0106] The recording medium also includes a ROM (Read Only Memory).

[0107] 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.

[0108] As described above, the configuration of the present invention may be realized in software or hardware. [Industrial Applicability]

[0109] The work vehicle of the present invention can improve usability and is useful for use as a work vehicle such as a rice transplanter. [Explanation of symbols]

[0110] 100 body 110 Controller 120 Straight-line assist start indicator 210 rear wheel 220 Fertilizer 230 Planetary gear mechanism 240 motor 310 Bumper 320 distance sensor 1001 Ground leveling rotor 1002 GPS device 1003 HST equipment 1004 Steering gear 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 Linear path reference point R Straight path

Claims

1. 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. 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. 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.

4. 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.

5. 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.

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