Work vehicle

Abstract

To maintain the safety of a worker while suppressing an increase in price compared to a conventional technology involving full automatic driving.SOLUTION: In a turn assist mode, control means (300) for switching between a manual drive mode, a straight assist mode, and a turn assist mode does not receive an input of a change to drive speed via a drive operation tool (33). Thus, the safety of a worker can be secured while suppressing an increase in price compared to a conventional technology involving full automatic drive.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a work vehicle, such as a rice transplanter or a tractor, that performs work in a farm field. [Background technology]

[0002] BACKGROUND ART Among work vehicles such as rice transplanters and tractors, there are known unmanned work vehicles that perform work while autonomously traveling within a field, so-called robotic agricultural machines (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-91609 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 requires the installation of obstacle sensors, drive control to prevent stuck vehicles, and the like on the work vehicle for unmanned driving, which raises the problem of the work vehicle's cost. In particular, current safety standards preclude completely unmanned operation and require manned monitoring in order to respond to emergency situations. Therefore, even if expensive equipment is installed, there is a problem in that a worker is still required to perform the work. When a worker is on board the work vehicle, the worker can make the decision and operate the vehicle to avoid obstacles, etc., and expensive safety devices for obstacle avoidance are not required. However, there is a risk of an accident in which the occupant falls, etc., if the vehicle makes a sudden stop, which is possible with automated driving that assumes no human is on board.

[0005] The technical objective of the present invention is to ensure the safety of workers while keeping costs down compared to conventional technologies that perform fully automatic driving. [Means for solving the problem]

[0006] The above-mentioned problems of the present invention are solved by the following means. The invention described in claim 1 is a work vehicle comprising a vehicle body (4), a travel operating device (33) for operating the travel of the vehicle body (4), and a control means (300) for switching between a manual travel mode in which the vehicle body (4) travels in accordance with the operation of the travel operating device (33), a straight-line assist mode in which the vehicle body (4) automatically travels in a predetermined straight direction at a travel speed in accordance with the operation of the travel operating device (33), and a turning assist mode in which the vehicle body (4) automatically turns by controlling it with a predetermined steering angle, wherein the control means (300) does not accept input for changing the travel speed by the travel operating device (33) in the turning assist mode.

[0007] The invention described in claim 2 is the work vehicle described in claim 1, characterized in that when automatic turning in the turning assist mode ends and the vehicle enters a straight-ahead driving state, the control means (300) accelerates or decelerates the vehicle body (4) in accordance with the driving speed set by the driving operating device (33).

[0008] The invention described in claim 3 is the work vehicle described in claim 1, characterized in that it comprises a seat sensor (SN1) provided in the seat (1) where the worker sits, which detects the worker being seated, and the control means (300) which issues an alert to encourage the worker to take a seat if the seat sensor (SN1) does not detect the worker being seated during the straight-line assist mode, and which stops the vehicle body if the seat sensor (SN1) does not detect the worker being seated during the turning assist mode.

[0009] The invention described in claim 4 is the work vehicle described in claim 1, characterized in that it comprises: a positioning device (111) arranged on the vehicle body (4) that performs positioning by communication with artificial satellites; a differential method that acquires the difference between the positioning result at a reference station whose coordinate information is known and the coordinate information as correction information and corrects the positioning result of the positioning device (111) with the correction information; and a real-time kinematic method that corrects the positioning result of the positioning device (111) based on the phases of signals from multiple artificial satellites observed at the reference station and the phases observed by the positioning device (111), and the control means (300) is capable of positioning using the differential method when, during the straight-line assist mode or the turning assist mode, there is an insufficient number of communicable satellites and positioning using the real-time kinematic method becomes impossible.

[0010] The invention described in claim 5 is a work vehicle described in claim 4, characterized in that it is equipped with the control means (300) that automatically acquires information on a position (411) that is a predetermined distance from the edge of the bank (406) and a position (412) that is a predetermined distance before the turning start position (407) as position information required for positioning using the differential method while traveling using positioning using the real-time kinematic method.

[0011] The invention described in claim 6 is the work vehicle described in claim 4, characterized in that it is provided with the control means (300) that does not start the straight-line assist mode even if an input to start the mode is given when positioning using the real-time kinematic method is not possible. [Effects of the Invention]

[0012] According to the invention described in claim 1, the control means (300) that switches between manual driving mode, straight-line assist mode, and turning assist mode does not accept input to change the driving speed using the driving operation device (33) in the turning assist mode, thereby ensuring the safety of the operator while keeping costs down compared to conventional technologies that perform fully automatic driving.

[0013] According to the invention of claim 2, in addition to the effect of the invention of claim 1, when automatic turning in the turning assist mode is completed and the vehicle enters a straight-ahead driving state, the vehicle body (4) is accelerated or decelerated in accordance with the driving speed set by the driving operation device (33), thereby ensuring safety during turning while allowing the vehicle to travel in a straight-ahead driving state according to the operator's operation.

[0014] According to the invention of claim 3, in addition to the effects of the invention of claim 1, if the seat sensor (SN1) does not detect any occupancy in the seat during straight-line assist mode, an alert is issued to encourage the occupant to sit down, and if the seat sensor (SN1) does not detect any occupancy in the seat during turning assist mode, the vehicle body is stopped, thereby ensuring safety during turning and suppressing a decrease in workability compared to stopping in straight-line assist mode.

[0015] According to the invention described in claim 4, in addition to the effect of the invention described in claim 1, if positioning using the real-time kinematic method becomes impossible during straight-line assist mode or turning assist mode, the positioning method is automatically switched to continue driving using differential positioning, allowing work to continue.

[0016] According to the invention described in claim 5, in addition to the effect of the invention described in claim 4, by automatically acquiring information on the position (411) a predetermined distance from the edge of the bank (406) and the position (412) a predetermined distance before the turning start position (407), the direction of travel can be smoothly acquired even when switching to the differential system.

[0017] According to the invention of claim 6, in addition to the effect of the invention of claim 4, if positioning using the real-time kinematic method is not possible, the straight-line assist mode will not be started even if an input to start the mode is made, thereby improving the operating accuracy of the straight-line assist mode. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a side view of the seedling transplanter according to the embodiment. [Figure 2]Figure 2 is a front view of the seedling transplanter. [Figure 3] Figure 3 is a plan view of the seedling transplanter. [Figure 4] FIG. 4 is a functional block diagram of the control unit according to the embodiment. [Figure 5] FIG. 5 is an explanatory diagram of a travel route in an example of a farm field according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the present invention will be described below. FIG. 1 is a side view of the seedling transplanter according to the embodiment. Figure 2 is a front view of the seedling transplanter. Figure 3 is a plan view of the seedling transplanter.

[0020] The seedling transplanter, which is an example of a work vehicle according to an embodiment of the present invention, has a seedling planting unit 10, which is an example of a work machine and is a multi-row planting machine body, attached to the rear of a vehicle body 4 in a high-floor riding mode via a parallel link lift link mechanism 11 that is raised, lowered, and rotated by the hydraulic expansion and contraction of a lift cylinder (not shown). This seedling planting unit 10 has multiple floats 6, such as a center float and side floats, that glide and level the soil surface, arranged on the underside of the seedling transplanter body 5 connected to the lift link mechanism 11. The seedling transplanting machine body 5 is mainly composed of a transmission case, and is equipped with a seedling tank 8 that lays out a large number of mat seedlings on top of it and guides them along the downward sloping surface at the rear end before dispensing them to the seedling outlet 7 formed at the lower end, and a planting device 9 that separates and holds the mat seedlings dispensed at the seedling outlet 7 and inserts the planting claws into the leveled soil surface below, operating along a planting trajectory that is oval in side view, thereby allowing seedlings to be planted in multiple rows.

[0021] An engine (internal combustion engine) 30 is mounted under an engine cover 29 below the driver's seat (seat) 1 of the vehicle body 4, and a steering board 31, a steering handle 32, and other operating mechanisms (one example of a driving operation tool) 33 for operating the seedling transplanter are disposed in front of the driver's seat 1. The steering board 31 is provided with an LCD monitor (one example of a display unit) and various buttons and knobs (not shown) (one example of an input unit). The various buttons include a switch button for automatic driving (robot driving) mode, a switch button for straight-line assist mode, a switch button for turning assist mode, a switch button for manual driving mode (a button for ending automatic driving mode and assist mode), a forward start button, a reverse start button, a button for increasing and decreasing the driving speed, a button for raising and lowering the working implement (seedling planting unit 10), and a button for starting and stopping the working implement (seedling planting unit 10). The various buttons of the operation mechanism 33 are preferably provided within reach of the operator while seated in the driver's seat 1, and may be provided, for example, within a radius of 500 mm from the driver's seat 1, or on the steering wheel 32. Furthermore, the operation mechanism is not limited to being configured entirely with buttons, and may be in any form operable by the operator, such as dials, knobs, levers, etc.

[0022] Further, a high-mounted monitor 31a is provided at the front upper portion of the steering board 31 as an example of a display unit and an example of a notification means. On both the left and right sides of the driver's seat 1, steering board 31, and center floor 34 between them, a side floor 2 is formed that is long and wide and extends continuously from the front end of the vehicle body 4 to the rear fender 24 on the rear end. The driver and assistant workers can move back and forth on the top surface of this side floor 2 to easily perform tasks such as supplying mat seedlings and fertilizer.

[0023] The seedling transplanter shown in the figure is designed to have eight rows of seedlings and a wide width, so a sub-floor 35 of an appropriate width is added along the outside of the side floor 2 to accommodate the width of the seedling planting section 10. It is also possible to configure the machine without the sub-floor 35. On the front end of this sub-floor 35, a multi-tiered auxiliary seedling shelf 26 is provided on a support frame 36 erected from the side of the vehicle body 4, and mat seedlings can be loaded and stored thereon to be replenished in the seedling tank 8 at the rear. A step 37 for the operator to get on and off is provided on the outside of this sub-floor 35. A pair of left and right line-drawing markers 41 are also placed on the sides of the subfloor 35. The line-drawing marker 41 on the left and right side where seedlings have not yet been planted is deployed to draw a line on the surface of the field as a reference for traveling.

[0024] Behind the driver's seat 1, a wide, stepped rear floor 3 is formed extending to the rear ends of the side floors 2, and the front edge of the rear floor 3 is connected to the rear edge of the side floors 2 by an inclined plate 38 that slopes downwards in front, making it easy for the driver to move his / her feet. A short operating lever mechanism 39 is disposed at the lower end of the inclined plate 38, making it easy to operate from the driver's seat 1. A U-shaped guard rail 52 is formed at an upper position of the rear floor 3 by a rear edge 50 that runs along the rear edge and side edges 51 that run along the left and right edge, allowing the driver to maintain a safe working posture when refueling on the rear floor 3.

[0025] A rear fender 24 is configured above the rear wheels 27 of the vehicle body 4, and the left and right end portions of the rear floor 3 are configured above this rear fender 24. The front wheels 40 and rear wheels 27 are arranged within the lateral width of the side floor 2 and rear floor 3, but depending on the width of the rear wheels 27, they may extend outward from the lateral width of the rear floor 3. For this reason, the rear fender 24 may be configured to extend outward more widely than the outer end of the rear floor 3, or the underside of the rear floor 3 itself may be used as the rear fender 24. The drive power from the engine 30 is changed in speed by an HST (not shown) as an example of a transmission and transmitted to the rear wheels 27, thereby propelling the vehicle body 4. In the case of a four-wheel drive, the drive power is transmitted to the front wheels 40 in addition to the rear wheels 27.

[0026] A seedling planting section 10 is attached to the rear of the vehicle body 4 via a lift link mechanism 11 that can be raised and lowered. The seedling planting section 10 consists of a float 6 that slides on the soil surface and supports the seedling transplanting machine body 5, a seedling tank 8 that receives mat seedlings and delivers them to a seedling outlet 7 at the bottom of the rear, and a planting device 9 that separates and holds the mat seedlings delivered to the seedling outlet 7 and plants them on the soil surface leveled by the float 6. A number of fertilizer applicators 12 are arranged along the outer side of the rear floor 3 in the front-to-rear direction. The drive power is transmitted to each part of the seedling planting section 10 via a PTO shaft (not shown) to which the drive power is transmitted from the engine 30.

[0027] When planting seedlings with the seedling transplanter, the seedling planting section 10 is lowered and the planting device 9 operates on the soil surface leveled by each float 6, separating and holding the appropriate number of mat seedlings delivered to the seedling outlet 7 of the seedling tank 8, and planting them at a fixed depth on the leveled soil surface. When fertilizing the planted area with each planting device 9, granular fertilizer that has been stored in advance in the fertilizer hopper (an example of a storage section) 19 of the fertilizer applicator 12 is delivered by the delivery device 15. The delivered fertilizer is delivered by the force of air sent from the blower 13 through a duct under the rear floor 3, via the fertilizer hoses 25 for each fertilizer row, and is applied to the planting area near the planting area on the planting soil surface leveled by each float 6.

[0028] When the seedling planting section 10 is raised, the upper end of the seedling tank 8 can be raised to approach a position above the rear floor 3, making it easier for an operator to supply mat seedlings from above the rear floor 3, and enabling quick and accurate seedling supply. 1 and 3, the seedling transplanter of this embodiment is provided with a planting unit lifting / lowering switch 10a that can be operated by an operator on the seedling planting unit 10. When the planting unit lifting / lowering switch 10a is manually operated by the operator, a lift cylinder is activated to raise and lower the seedling planting unit 10. Therefore, even an assistant who carries seedlings or fertilizer can operate the planting unit lifting / lowering switch 10a to raise and lower the seedling planting unit 10. When refilling the seedling tank 8 with seedlings, herbicides, pesticides, etc., the assistant can do it alone at the rear of the vehicle body 4 without having to operate the lifting / lowering operation from the driver's seat 1, making the work smoother.

[0029] The planting unit lift switch 10a is preferably installed at the rear and on both the left and right ends of the seedling tank 8, making it easier for assistants to operate. The planting unit lift switch 10a may be a push switch with an up button and a down button, or a toggle switch may be used. The planting unit lift switch 10a can be controlled so that the seedling planting unit 10 rises or falls while being pressed up or down, and returns to a neutral position when the planting unit lift switch 10a is released, stopping the seedling planting unit 10. Another possible configuration is a push switch where the seedling planting unit 10 descends when pressed for a short time and rises when pressed for a long time.

[0030] It is preferable to enhance safety by using a notification means such as a buzzer, lamp, or voice guide to notify the operator or other assistants that the seedling planting unit 10 is moving while the planting unit lifting / lowering switch 10a is being operated. In this case, it is desirable to further enhance safety by providing a time lag (e.g., 0.5 seconds) between the notification by the buzzer or the like and the start of the seedling planting unit 10 lifting / lowering.

[0031] For safety reasons, it is preferable that the planting unit lifting / lowering switch 10a be controlled so that it operates only when the planting device 9 is stopped, i.e., when the planting switch is in the "off" position. Similarly, for safety reasons, it is preferable that the seedling planting unit 10 be raised or lowered only when the HST lever (an example of a travel operating tool) of the operating mechanism 33 is in the "neutral" position or when the clutch pedal is depressed. It is also preferable that the raising or lowering of the seedling planting unit 10 be stopped and a buzzer or other sound be sounded when the HST lever is in a position other than "neutral" or the clutch pedal is released.

[0032] Further, the left and right end portions of the rear floor 3 are configured as rear fenders 24 or configured as upper portions of the rear fenders 24, and the plurality of fertilizer applicators 12 are arranged above the rear fenders 24.

[0033] The left and right side ends of the rear floor 3 formed at the rear end of the side floor 2 next to the driver's seat 1 are positioned above the rear fender 24 that covers the upper part of the rear wheels 27 of the raised-floor body 4, so they are less likely to get in the way of stepping on and moving around when replenishing mat seedlings in the seedling tank 8 as described above, and the foot area at the lateral end of the rear floor 3 at the rear position of the side floor 2 is formed wide, making it easy to perform seedling replenishing operations in the rear seedling tank 8 and fertilizer replenishing operations in the fertilizer hopper 19 on the side.

[0034] (Explanation of the control unit of the seedling transplanter) FIG. 4 is a functional block diagram of the control unit according to the embodiment. The seedling transplanter of the embodiment has a control unit (an example of a control means) 300 that controls each function. The control unit 300 has an input / output interface I / O that performs input and output of signals with the outside. The control unit 300 also has a read-only memory (ROM) that stores programs and information for performing necessary processing. The control unit 300 also has a random access memory (RAM) for temporarily storing necessary data. The control unit 300 also has a central processing unit (CPU) that performs processing according to the programs stored in the ROM or the like. Therefore, the control unit 300 of the embodiment is configured with a small information processing device, a so-called microcomputer. Therefore, the control unit 300 can realize various functions by executing programs stored in the ROM or the like.

[0035] The control unit 300 receives signals from signal input elements such as a high-mounted monitor 31a, which is an example of an input unit and an example of a display unit and is composed of a touch panel, a positioning device 111, a teaching mode switch button 109, an automatic driving mode switch button 112, a straight-line assist mode switch button 113, a turning assist mode switch button 114, a manual driving mode switch button 115, a forward start button 116, a reverse start button 117, a driving speed increase button 118, a driving speed decrease button 119, a work machine (seedling planting unit 10) raise button 120, a work machine lower button 121, a work machine operation start button (planting start button) 122, a work machine operation stop button (planting stop button) 123, a sheet sensor SN1, and various other sensors not shown.

[0036] The positioning device 111 includes a GNSS (Global Navigation Satellite System) receiver 111a and an IMU (Inertial Measurement Unit) 111b. The GNSS receiver 111a receives positioning signals from artificial satellites and can measure the current position of the seedling transplanter. The IMU 111b measures acceleration and angular velocity and can measure the attitude of the seedling transplanter (left-right tilt and front-back tilt). Therefore, by correcting the measurement results of the GNSS receiver 111a with the IMU 111b, the current position can be measured more accurately than when the current position is measured using only the GNSS method.

[0037] The teaching mode switching button 109 is a button for switching to a teaching mode in which specific positions such as the four corners of a field are acquired and registered (teaching). The automatic travel mode switching button 112 is a button for switching to the automatic travel mode in which the robot automatically travels while working in a farm field, based on a specific position acquired in the teaching mode. The straight-line assist mode switching button 113 is a button for switching to a straight-line assist mode in which the robot automatically travels in a predetermined straight direction while working in a farm field (assists in traveling straight).

[0038] The turning assist mode switching button 114 is a button for switching to a turning assist mode in which the vehicle body 4 is automatically turned by controlling it with a predetermined steering angle. The manual driving mode switching button 115 is a button for switching to a manual driving mode in which the vehicle body 4 is driven manually in response to the operation of the steering wheel 32, accelerator pedal, etc. Therefore, if the automatic driving mode, straight driving assist mode, or turning assist mode needs to be terminated midway, it can be terminated midway by pressing the manual driving mode switching button 115.

[0039] The forward start button 116 is a button for switching the forward / reverse clutch 201 to the forward side. The reverse start button 117 is a button for switching the forward / reverse clutch 201 to the reverse side. The travel speed increase button 118 is a button for switching the HST 202, which is an example of a transmission, to the speed increase side. Note that the travel speed increase button 118 of the embodiment can increase the speed by a predetermined step by pressing it once, and can continue to increase the speed by pressing it multiple times or holding it down.

[0040] The travel speed deceleration button 119 is a button for switching the HST 202 to the deceleration side, in contrast to the travel speed increase button 118. The work machine lift button 120 is a button for lifting the work machine (seedling planting unit 10) via the lift cylinder 203. In the embodiment, the work machine lift button 120 is configured to continue to lift the work machine while an input is being made, but this is not limited to this, and it is also possible to configure the work machine to be lifted to a predetermined distance or position with a single input. The work machine lowering button 121 is a button for lowering the work machine (seedling planting unit 10) via the lift cylinder 203, in contrast to the work machine raising button 120.

[0041] The operation start button 122 for the work machine is a button for turning on the PTO clutch 204 and operating the work machine (seedling planting section 10). The work machine operation stop button 123 is a button for disengaging the PTO clutch 204 and stopping the operation of the work machine (seedling planting section 10). The seat sensor SN1, which is an example of a seat occupancy detection member, is installed in the driver's seat 1 and detects whether an operator or a driver is seated. Note that, although the embodiment exemplifies a mode in which the seat occupancy detection member detects whether a person is seated, this is not limiting. For example, a human presence sensor that detects surrounding people may also be used.

[0042] The control unit 300 can send control signals to the power supply circuit, as an example of a controlled element, the fertilizer applicator 12, the engine 30, the forward / reverse clutch 201, the HST 202, the steering handle 32, the lift cylinder 203, the PTO clutch 204, etc., to control the operation / stop of the fertilizer applicator 12, the raising and lowering and operation / stop of the seedling planting unit 10 (work machine), the rotation of the engine 30, the switching between forward and reverse, the gear shifting and steering of the HST 202, etc. The control unit 300 can also output a control signal to a liquid crystal monitor or high-mount monitor 31a, which is an example of a display unit, to display work information and work status.

[0043] FIG. 5 is an explanatory diagram of a travel route in an example of a farm field according to an embodiment. The control unit 300 according to the embodiment has the following functional means (program modules). The field information storage means 301 stores information about the field 400 (field information). In this embodiment, as shown in FIG. 5, when teaching travel is performed by driving the vehicle body 4 along the outer edge of the field, specific positions in the field (for example, the four corners of the field) and their orientations are stored as field information. In teaching travel, the operator manually drives the vehicle body 4 along three sides 400a to 400c of the rectangular field while planting, and a total of four positions (401 to 404) - a teaching start position 401, two turning positions 402 and 403, and a teaching end position 404 - are registered (stored) as the four corners of the field 400. The remaining side, where planting is not performed, is registered as a supply side 400d for supplying seedlings, fertilizer, and other materials. In this embodiment, teaching travel starts when the teaching mode switch button 109 is pressed, and when the teaching mode switch button 109 is pressed during teaching travel, the corner position is registered, and when the teaching mode switch button 109 is pressed and held, the teaching travel ends. Note that a position registration button and a teaching end button may also be provided separately. Note that the direction is obtained using a compass (magnetic bearing) not shown, but it may also be derived from the GNSS positioning results and the measurement results of the IMU 111b.

[0044] In this embodiment, the field information is displayed on the high-mounted monitor 31a, so that the operator can check it. Therefore, the operator can operate and drive the seedling transplanter while checking the field information and the current position displayed on the high-mounted monitor 31a.

[0045] The positioning means 302 has an RTK positioning means 302a and a differential positioning means 302b, and measures the current position of the seedling transplanter based on the measurement results of the positioning device 111. The RTK positioning means 302a performs positioning using a Real Time Kinematic (RTK) method that corrects the positioning results of the positioning device 111 based on the phases of signals from multiple (four or more) satellites observed at a reference station whose coordinate information is known and the phases of signals from multiple satellites observed by the positioning device 111.

[0046] The differential positioning means 302b acquires the difference between the positioning result at a reference station whose coordinate information is known and the coordinate information as correction information, and performs positioning using a differential method in which the positioning result of the positioning device 111 is corrected with the correction information from the reference station. Note that RTK positioning and differential positioning are well known and therefore will not be described in detail. Generally, the error of the RTK method (several tens of centimeters) is smaller than the error of the differential method (several meters). However, the RTK method has the problem that positioning becomes impossible when communication with a satellite is interrupted and the number of communicable satellites is insufficient. Therefore, the positioning means 302 of the embodiment performs positioning using the RTK method when positioning is possible using the RTK method, and switches to the differential method when positioning is not possible using the RTK method. Furthermore, the positioning means 302 corrects the positioning results acquired using GNSS with the inclination of the vehicle body 4 acquired by the IMU 111b, thereby improving positioning accuracy compared to when the inclination of the vehicle body 4 is not taken into account.

[0047] While traveling using real-time kinematic positioning, the position information storage means 303 automatically acquires and stores information on a position (point A 411) that is a predetermined distance (e.g., 3 m) from the bank edge 406 and a position (point B 412) that is a predetermined distance (e.g., 3 m) before the turning start position 407, as position information required for differential positioning. When performing straight-line assisted traveling, it is necessary to set the direction of travel (forward direction). However, if the system switches from the RTK system to the differential system midway, there is a risk that the direction of travel cannot be determined immediately after the switch due to a lack of information. Therefore, to be able to deal with midway switching, the position information on points A 411 and B 412 is acquired as needed, and when the system switches, the direction of travel for the current straight-line travel path 410b (the opposite direction of the previous straight-line travel path) can be acquired from the direction from point A 411 to point B 412 of the previous straight-line travel path 410a, and the straight-line travel direction of the vehicle body 4 can be determined. It is possible to store all previously acquired position information for point A 411 and point B 412 as history information, or to erase the information for past point A 411 or point B 412 when a new point A 411 or point B 412 is acquired, or to erase the information when new teaching is performed.

[0048] The operation detection means 304 detects input operations of the buttons 109, 112 to 123 of the operation mechanism 33. Therefore, the operation detection means 304 detects whether or not an input has been made for the automatic driving mode, the straight driving assist mode, forward / reverse movement, acceleration / deceleration, lifting / lowering or operation of the work implement, or the like, in other words, whether or not an input has been made to permit the start of the automatic driving mode, etc., or to permit forward / reverse movement, etc. After the automatic driving mode, the straight driving assist mode, or the turning assist mode has started, it is also possible to configure the system so that inputs from the reverse movement start button 117, the travel speed increase button 118, the travel speed decrease button 119, the work implement raise button 120, the work implement lower button 121, the work implement operation start button 122, and the work implement operation stop button 123 are not accepted, and inputs are accepted only when a specific operation (such as pressing multiple buttons simultaneously or holding them down) is performed, thereby preventing erroneous operation. Alternatively, an input acceptance (input permission) button may be provided in each mode, and for example, when the driving speed increase button 118 is pressed while pressing the input acceptance button, the input of the driving speed increase button 118 may be accepted.

[0049] Furthermore, while the embodiment illustrates an example in which work instructions are given using buttons 109, 112 to 123, the present invention is not limited to this. It is also possible for the operator to give instructions by voice, i.e., a so-called interactive operation system. For example, if the operator gives instructions by speaking, such as "Please increase speed," or the seedling transplanter issues a voice guidance message saying, "We will turn left soon," and the operator replies "OK" and gives permission, the operation detection means 304 detects that the left turn has been instructed and permitted, and the voice guidance replies, "Left turn permitted." If the operator does not reply or give permission within a predetermined time, it is also possible to determine that permission has not been granted and stop the vehicle body 4. It is also possible to provide both interactive input and input from buttons 109, 112 to 123, and it is also possible for the operator to set the system so that only either interactive input or button input is accepted.

[0050] The mode switching means 305 switches between teaching mode, automatic driving mode, straight driving assist mode, turning assist mode, and manual driving mode in response to input from the operation detection means 304. In this embodiment, when the teaching mode switching button 109 is pressed, the mode switching means 305 switches to the teaching mode if RTK positioning is possible and the direction has been acquired. In the teaching mode, the four corners 401 to 404 of the field 400 are acquired and registered in response to the input of the teaching mode switching button 109.

[0051] When the teaching mode switch button 109 is pressed, if RTK positioning is not possible, if the operator's input / settings have been set to differential positioning, or if the orientation cannot be acquired, a message indicating that the teaching mode cannot be started is displayed on the high-mounted monitor 31a. If the operator's input / settings have been set to differential positioning, it is also possible to configure the system to automatically switch to the RTK method when the teaching mode switch button 109 is pressed. Note that in seedling transplanters that are not equipped with a compass, it is also possible to configure the system to acquire and register the orientation from the measurement results of the IMU 111b and the positioning results of the GNSS after the teaching mode is started.

[0052] When the automatic driving mode switch button 112 is pressed, the mode switching means 305 switches to the automatic driving mode if RTK positioning is possible and the steering wheel 32 is in the neutral position. In the automatic driving mode, a straight path 410, a turning path 420, and a revolving path 430 are automatically generated based on the four corners 401 to 404 of the field 400 obtained by teaching driving. Then, when the forward movement start button 116 is pressed, the automatic driving mode is initiated, in which automatic driving is performed while working with the work implement in the straight path 410 and the turning path 430, and the work implement is raised and turned in the turning path 420. Then, when the work end position (in this embodiment, the end position 431 of the turning path 430) is reached, the automatic driving mode is automatically terminated and the mode is switched to the manual driving mode.

[0053] Note that if the operator is not aware of or mentally prepared for the transition from the straight travel path 410 to the turning path 420 during automatic travel, the vehicle may unexpectedly start turning, resulting in safety concerns such as tipping over. Therefore, when the vehicle body 4 reaches a notification position 413 (which may be the same position as point B 412 or a different position (e.g., 8 m before)) that is a predetermined distance before the turning start position 407, it is desirable to notify the operator via the high-mounted monitor 31a or the like that the turning start position is approaching, i.e., that the vehicle will soon begin turning. Note that the distance between the turning start position 407 and the notification position 413 may be a fixed value, or may be changeable by the operator. Furthermore, the notification position 413 does not have to be determined by the distance from the turning start position 407, but may be arbitrarily changed, for example, to a position 3 seconds before the vehicle reaches the turning start position 407 based on the traveling speed. Furthermore, although it is desirable to be notified, it is also possible to set the system so that no notification is made to workers who do not wish to be notified.

[0054] In addition, in order to improve safety in the automatic driving mode, for example, it is possible to cancel the automatic driving mode when the steering wheel 32 is operated beyond a certain angle, or to cancel the automatic driving mode and stop the vehicle body 4 if the measurement results of the IMU 111b indicate that the vehicle body 4 tilts beyond a certain angle, which is dangerous and may cause the vehicle to run over an obstacle or a bank.

[0055] Furthermore, when the straight driving assist mode switch button 113 is pressed, if RTK positioning is possible and the steering wheel 32 is in the neutral position, the mode switching means 305 switches to straight driving assist mode. Therefore, in this embodiment, if positioning cannot be performed using the RTK method, the teaching mode, automatic driving mode, or straight driving assist mode is not initiated, and a notification to that effect is displayed on the high mounted monitor 31a. The notification method is not limited to the high mounted monitor 31a, and any method can be used, such as audio guidance, lighting or flashing of a lamp, or sounding of a buzzer. Note that, in the embodiment, an example is given in which the teaching mode, automatic driving mode, and straight-line assist mode are not started when positioning cannot be performed using the RTK method, but this is not limiting. For example, it is also possible to configure a configuration in which the turning assist mode cannot be started when positioning cannot be performed using the RTK method, or to configure a configuration in which the teaching mode and automatic driving mode cannot be started, and the straight-line assist mode and turning assist mode can be started using the differential method. In addition, when the straight-line assist mode and turning assist mode are started, it is also possible to configure a configuration in which the positioning method is automatically switched to the RTK method or the differential method.

[0056] In addition, in the embodiment, if RTK positioning becomes impossible midway through the start of the automatic driving mode or straight-line assist mode, the automatic driving mode continues using the differential system. When RTK positioning becomes possible again, the automatic driving mode continues using the RTK system. When switching to the differential system, it is preferable to notify the operator of a decrease in accuracy using the high-mounted monitor 31a, voice guidance, a buzzer, or the like, and prompt the operator to decide whether to continue working with lower accuracy. It is also possible to switch to the differential system only if the operator gives permission. In addition, in the embodiment, the automatic driving mode and the straight-line assist mode automatically switch to the differential system when RTK positioning becomes impossible. However, this is not limiting. For example, the automatic driving mode may only use the RTK system, and the automatic driving mode may be terminated when RTK positioning becomes impossible. Alternatively, if RTK positioning becomes impossible during the teaching mode, a warning message may be displayed informing the operator that teaching will be performed. It is desirable to make it easy for operators to check the situation by displaying the RTK reception level on the high-mounted monitor 31a, graying out the display if RTK positioning is not possible, or displaying whether the current positioning method is RTK or differential.

[0057] If RTK positioning is not resumed while the differential mode is in operation, it is possible to continue using the differential mode until the end, but this is not a limitation. For example, when the vehicle reaches a turning start position 407 on the supply side 400d side (where maintenance is easy through the unworked supply side 400d) during straight travel 410, the vehicle body 4 can be stopped and switched to manual travel mode, and the automatic travel mode or the like cannot be resumed until RTK positioning is resumed. Then, when RTK positioning becomes possible, it is desirable to display this on the high-mounted monitor 31a or the like to notify the operator that the automatic travel mode or the like can be resumed. Furthermore, if positioning is not possible using either the RTK method or the differential method, it is desirable to display this fact on the high-mounted monitor 31a and stop the vehicle body 4.

[0058] In the straight-line assist mode, the direction connecting the corners (401, 402) of the longest of the three outer edges 400a of the field is set as the straight-line direction based on the information obtained during teaching. The vehicle automatically travels along the straight-line direction (in a direction parallel to the straight-line direction) from the position where the straight-line assist mode switch button 113 is pressed. After switching to the straight-line assist mode, pressing the forward movement start button 116 initiates the straight-line assist mode. That is, the vehicle travels at a predetermined working speed, the implement lowers, and work is performed through operation. Based on the positioning results, the vehicle automatically steers to travel in a straight-line direction. In this embodiment, during the straight-line assist mode, the vehicle can accelerate or decelerate by operating the travel speed increase button 118 or the travel speed decrease button 119. Based on the information obtained during teaching, when the vehicle reaches a turning start position 407, a predetermined distance before the ridge edge 406, the straight-line assist mode is terminated and the vehicle switches to the manual travel mode.

[0059] Furthermore, the mode switching means 305 switches to the turning assist mode when the turning assist mode switching button 114 is pressed. In the turning assist mode, automatic turning travel is performed from the position where the turning assist mode switching button 114 is pressed, based on a predetermined steering angle (turning angle, turning radius). After switching to the turning assist mode, when the work implement lift button 120 is pressed and the work implement is raised, the turning assist mode is initiated. In the turning assist mode of the embodiment, automatic steering is performed at a predetermined steering angle while traveling at a traveling speed for turning, regardless of the input from the operation mechanism 33. In the embodiment, the traveling speed is not changed even if the traveling speed increase button 118 or the traveling speed decrease button 119 is operated during the turning assist mode. In other words, input to change the traveling speed is not accepted. Then, when it is determined from the positioning results of the vehicle body 4 that the position of the vehicle body 4 has moved from the turning start position 407 to the turning end position 408, which is moved by the working width, the turning assist mode is ended and the mode is switched to the manual driving mode. Note that when the turning assist mode is switched to the manual driving mode, the mode is switched from automatic turning to a straight driving state, and at this time the driving speed is accelerated or decelerated from the turning driving speed to the driving speed input and set by the operation mechanism 33.

[0060] In the embodiment, an example has been given in which changes in driving speed are not accepted during turning assist mode, but it is also possible to similarly not accept changes in driving speed during turning in automatic driving mode. In addition, in the turning assist mode, it is desirable to display the turning direction on the high-mount monitor 31a, move the line drawing marker 41 on the turning side, or raise and lower the front marker to notify the operator of the turning direction.

[0061] If the vehicle body 4 becomes unable to turn midway during the turning assist mode due to getting stuck in a deep hole or the like (for example, if a predetermined time has passed without the steering angle of the steering wheel 32 reaching the desired steering angle, or if the measured position of the vehicle body 4 does not move even after a predetermined time has passed), it is possible to determine that the turning assist mode cannot be continued, and to stop the vehicle body 4 or switch to manual driving mode. If it is determined that the turning assist mode cannot be continued, it is desirable to show the operator how to respond by displaying a message to that effect on the high-mounted monitor 31a or by displaying on the high-mounted monitor 31a guidance for the operator to operate the vehicle manually (for example, "Turn the steering wheel 30 degrees to the right," "Keep the vehicle in a straight line and escape the deep hole," or "Depress the differential lock pedal").

[0062] In this embodiment, when the automatic driving mode is not used, the operator alternates between the straight driving assist mode and the turning assist mode. Therefore, arranging the straight driving assist mode switching button 113 and the turning assist mode switching button 114 adjacent to each other makes them easier for the operator to operate. Also, since it is expected that the automatic driving mode will be switched directly after the teaching mode, it is preferable to arrange the teaching mode switching button 109 and the automatic driving mode switching button 112 adjacent to each other.

[0063] Furthermore, when the mode is switched in the mode switching means 305, for example, when the mode is switched from a straight-line assist mode to a turning assist mode, or when the mode is switched from an automatic driving mode to a manual driving mode, or when the positioning method is switched, it is preferable that the vehicle body 4 is temporarily stopped to notify the user that the mode has been changed or that the positioning method has been switched.

[0064] The travel control means 306 controls the travel of the seedling transplanter by controlling the engine 30, HST 202, forward / reverse clutch 201, and steering handle 32. In this embodiment, the travel control means 306 controls the engine 30 etc. in response to the operator's operation of the steering handle 32 and the operating mechanism 33, such as the accelerator pedal, brake pedal, HST lever, etc., and various buttons 109, 112 to 123. The work machine control means 307 controls the seedling planting section 10. The work machine control means 307 in this embodiment controls the lift cylinder 203, the PTO clutch 204, etc., to control the raising and lowering and operation / stop of the seedling planting section 10.

[0065] The seat occupancy determination means 308 determines whether the operator is seated or not in the driver's seat 1, i.e., whether the operator is seated or not, based on the detection result of the seat sensor SN1. If the seat occupancy determination means 308 determines that the operator is not seated (no seating detected) during the straight-line assist mode, it issues a notification urging the operator to take a seat. The notification is made by displaying a message on the high-mounted monitor 31a, but is not limited to this and can be made by any method, such as audio guidance, sounding a buzzer, lighting a lamp, flashing a lamp, etc. Furthermore, if it is determined that the operator is not seated during the turning assist mode or the automatic driving mode, it forcibly switches to the manual driving mode and stops the vehicle body 4. In other words, the seedling transplanter of this embodiment behaves differently when the operator is not seated depending on the mode. Note that when stopping in the turning assist mode, it is also possible to provide a notification, such as a display on the high-mounted monitor 31a or audio guidance. At this time, it is possible to use different notification methods in the straight-line assist mode and in the turning assist mode, for example, by changing the volume of the buzzer, changing the color of the lamp, providing multiple buzzers and changing the number of buzzers that sound, or by moving the line markers 41 on both sides in small increments when stopping, or in any other manner.

[0066] (Operation of the embodiment) In the seedling transplanter of the embodiment having the above configuration, in the turning assist mode, even if an input for acceleration / deceleration (change in traveling speed) is made during the turning assist mode, the input for changing the traveling speed is not accepted. Therefore, sudden acceleration or deceleration due to an incorrect operation while turning is prevented, reducing the risk of accidents such as tipping or falling of the operator or passenger, thereby improving safety. Furthermore, since the operator is on board, he or she can identify obstacles and take action to avoid them. Therefore, expensive safety devices such as sonar and camera units for obstacle detection and avoidance are not required, which helps to reduce the price of the seedling transplanter.

[0067] In this embodiment, when the turning (turning assist mode) ends and the vehicle transitions to straight-ahead driving, and the risk of tipping over decreases, the vehicle is accelerated or decelerated to the traveling speed set by the operation mechanism 33. Therefore, it is possible to drive the vehicle in accordance with the operator's input while ensuring safety. In particular, in this embodiment, if it is determined that the driver has left the seat during the turning assist mode, the vehicle body 4 is stopped because it would be dangerous to continue driving. On the other hand, in the straight-line assist mode, even if the driver leaves the seat to replenish seedlings, etc., the risk of tipping over is low while driving straight, so a notification is issued urging the driver to take a seat, but the vehicle body 4 is not stopped and the work driving continues. This ensures safety while suppressing a decrease in work efficiency.

[0068] Furthermore, in this embodiment, the positioning means 302 performs positioning using the RTK method and the differential method. Therefore, by using the RTK method, which has high positioning accuracy, as a general rule, work accuracy and driving accuracy are improved. In particular, when positioning using the RTK method is not possible, the automatic driving mode and straight-line assist mode are not started, and driving in the automatic driving mode and straight-line assist mode is possible with highly accurate positioning. Furthermore, even if positioning using the RTK method becomes impossible, work can be continued using differential positioning without stopping the vehicle body 4, thereby suppressing a decrease in work efficiency. In particular, even while positioning is being performed using the RTK method, point A 411 and point B 412 are acquired at any time, so the direction of travel can be quickly set even when switching to the differential method, and automatic driving can be continued smoothly even when the positioning method is switched.

[0069] (Example of change) The work vehicle of the present invention is not limited to a seedling transplanter, but can also be applied to various work vehicles capable of fertilizing or spraying pesticides, such as tractors and pesticide spraying vehicles. Furthermore, in the embodiment, the field information storage means 301 is provided in the seedling transplanter, but this is not limiting. For example, it is also possible to store field information in a server (an example of an information processing device, an example of a computer device) that can communicate with the seedling transplanter via a communication line and distribute the field information to the seedling transplanter. Furthermore, the processing of each of the means 301 to 308 is not limited to being centralized in the seedling transplanter, and it is also possible to have distributed processing among multiple information processing devices connected by a communication line.

[0070] Furthermore, although a work vehicle powered by an engine 30 has been exemplified as a work vehicle, the present invention is not limited to this. The present invention can also be applied to work vehicles that are equipped with an engine and a motor and use the motor to assist the engine's power, so-called hybrid vehicles, and electric vehicles that run and operate work equipment using only the motor. [Explanation of symbols]

[0071] 1...seat, 4...car body, 33...Travel control device, 111...positioning equipment, 300...control means, 406...shore, 407...Turning start position, 411...A location a specified distance from the edge of the river, 412...position a predetermined distance before the turning start position, SN1...Seat sensor.

Claims

1. A car body (4), a travel operating device (33) for operating the travel of the vehicle body (4); a control means (300) for switching between a manual driving mode in which the vehicle body (4) is driven in response to the operation of the driving operation device (33), a straight driving assist mode in which the vehicle body (4) is automatically driven in a predetermined straight direction at a driving speed in response to the operation of the driving operation device (33), and a turning assist mode in which the vehicle body (4) is automatically turned by controlling it at a predetermined steering angle; Equipped with In the turning assist mode, the control means (300) does not accept an input for changing the traveling speed by the traveling operation tool (33). A work vehicle characterized by:

2. When the automatic turning in the turning assist mode is completed and the vehicle enters a straight running state, the control means (300) accelerates or decelerates the vehicle body (4) in accordance with the running speed set by the running operation device (33).

2. The work vehicle according to claim 1.

3. a seat sensor (SN1) provided on a seat (1) on which an operator sits and which detects the operator's seating; the control means (300) for issuing a notification to encourage a person to take a seat when the seat sensor (SN1) does not detect a person seated during the straight-line assist mode, and for stopping the vehicle body when the seat sensor (SN1) does not detect a person seated during the turning assist mode; 2. The work vehicle according to claim 1, further comprising:

4. a positioning device (111) disposed on the vehicle body (4) and performing positioning by communicating with an artificial satellite; The control means (300) is capable of performing positioning using a differential method that acquires, as correction information, a difference between a positioning result at a reference station whose coordinate information is known and the coordinate information, and corrects the positioning result of the positioning device (111) using the correction information, and a real-time kinematic method that corrects the positioning result of the positioning device (111) based on the phases of signals from multiple artificial satellites observed at the reference station and the phases observed by the positioning device (111), and when, during the straight-line assist mode or the turning assist mode, the number of communicable artificial satellites is insufficient and positioning using the real-time kinematic method becomes impossible, the control means (300) continues traveling using positioning using the differential method; 2. The work vehicle according to claim 1, further comprising:

5. the control means (300) automatically acquiring information on a position (411) a predetermined distance from the edge of a bank (406) and a position (412) a predetermined distance before the turning start position (407) as position information required for positioning by a differential method while traveling using positioning by the real-time kinematic method; 5. The work vehicle according to claim 4, further comprising:

6. the control means (300) not starting the straight-line assist mode even if an input to start the mode is given when positioning by the real-time kinematic method is impossible; 5. The work vehicle according to claim 4, further comprising:

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