Work vehicles

Abstract

To provide a work vehicle capable of autonomous driving at low cost. [Solution] The system includes a first operating means for switching between forward and reverse movement, a second operating means for setting the vehicle speed during automatic driving, and a control device for executing automatic driving. When the second operating means is operated during automatic driving, the vehicle speed is changed while maintaining automatic driving. The system also includes a position detection device that uses first positioning and a highly accurate second positioning, and the control device performs automatic driving based on the second positioning. Furthermore, even if the second positioning becomes impossible during automatic driving, at least one of straight-line assist driving or turning assist driving can be performed using the first positioning.

Description

Technical Field

[0001] The present invention relates to a work vehicle.

Background Art

[0002] Conventionally, there is known a work vehicle that can travel without a driver (see, for example, Patent Document 1). Such a work vehicle performs automatic driving for field work without depending on an operation by a driver. Such a work vehicle is equipped with an obstacle sensor for detecting obstacles and drive control for suppressing stacking of the work vehicle in the field.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-described work vehicle requires sensors and the like, and thus becomes expensive. Further, although the above-described work vehicle can perform work without a driver getting on the work vehicle, in order to proceed with the work, an operator needs to monitor the work vehicle near the field.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a work vehicle capable of performing automatic driving at low cost.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a work vehicle according to an aspect of the embodiment is The vehicle includes a first operating means for switching the forward and reverse movement of the vehicle, a second operating means for setting the vehicle speed of the vehicle while it is automatically driving, and a control device for causing the vehicle to automatically drive, wherein the control device changes the vehicle speed of the vehicle while maintaining the automatic driving when the second operating means is operated during automatic driving, and includes a position detection device capable of detecting the position of the vehicle by first positioning and second positioning, wherein the second positioning has higher detection accuracy than the first positioning, and the control device executes automatic driving based on the position of the vehicle detected by the second positioning, and if the position of the vehicle cannot be detected by the second positioning during automatic driving, at least one of straight-line assist driving and turning assist driving can be performed by the first positioning. [Effects of the Invention]

[0007] According to one embodiment, a work vehicle capable of autonomous driving can be provided at a low cost. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a side view showing a work vehicle according to the first embodiment. [Figure 2] Figure 2 is a plan view showing a work vehicle according to the first embodiment. [Figure 3] Figure 3 is a block diagram showing the control system, centered on the control device of the seedling transplanter according to the first embodiment. [Figure 4] Figure 4 shows the method for setting the work area by teaching travel according to the first embodiment. [Figure 5] Figure 5 is a flowchart illustrating the autonomous driving control according to the first embodiment. [Figure 6] Figure 6 is a side view showing a seedling transplanter according to the second embodiment. [Figure 7] Figure 7 is a block diagram showing the control system centered on the controller of the seedling transplanter according to the second embodiment. [Figure 8]Figure 8 is a flowchart illustrating the autonomous driving control according to the second embodiment. [Modes for carrying out the invention]

[0009] (First Embodiment) First, an overview of the work vehicle 1 according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a side view showing the work vehicle 1 according to the first embodiment. Figure 2 is a top view showing the work vehicle 1 according to the first embodiment.

[0010] In the following explanation, the forward and backward directions refer to the direction of travel when the work vehicle 1 is moving straight, with the front side of the direction of travel defined as "forward" and the rear side as "rear." The direction of travel of the work vehicle 1 is the direction from the driver's seat 41, where the driver can sit, toward the steering wheel 35 (steering device) when moving straight (see Figures 1 and 2).

[0011] The left-right direction is the direction perpendicular to the front-back direction, and left and right are defined with respect to the "front" side. That is, with the driver (also called the operator) seated in the cockpit 41 and facing forward, the left side is "left" and the right side is "right".

[0012] The vertical direction refers to the vertical direction. The front-back, left-right, and up-down directions are orthogonal to each other. These directions are defined for the sake of explanation, and the present invention is not limited by these directions.

[0013] Here, the work vehicle 1 is described as a ride-on seedling transplanter 1 equipped with a seedling planting unit 4 as a work machine that receives seedlings in the field. As shown in Figures 1 and 2, the seedling transplanter 1 is equipped with a liftable seedling planting unit 4 on the rear side of the traveling vehicle body 2 via a lifting link mechanism 3 for planting seedlings in the field.

[0014] The main body of the fertilizer application device 5 is positioned on the upper rear side of the vehicle body 2. If the work vehicle 1 is not a seedling transplanter 1, it may be equipped with a seeding device or other work equipment for supplying seeds.

[0015] The traveling vehicle body 2 is a four-wheel drive vehicle provided with left and right front wheels 10 and rear wheels 11, which are wheels and drive wheels. On the front side of the main frame 15 that constitutes the vehicle body skeleton of the traveling vehicle body 2, there are a transmission case 13 that transmits driving force to the seedling planting unit 4 and the like, and a hydraulic continuously variable transmission device 14 that outputs the driving force supplied from the engine 30, that is, the rotation generated by the engine 30, to the transmission case 13.

[0016] The continuously variable transmission device 14 is a hydrostatic continuously variable transmission called a so-called HST (Hydro Static Transmission). Hereinafter, the case where the continuously variable transmission device is the HST 14 will be described.

[0017] In the transmission case 13, a sub-transmission mechanism 16 for switching the traveling mode of the traveling vehicle body 2 during road travel in the high-speed mode or during seedling planting in the low-speed mode is provided. Front wheel final cases 10a are provided on the left and right sides of the transmission case 13, and the front wheels 10 are attached to the left and right front axles 10b that protrude outward from the front wheel support portions capable of changing the steering direction of the left and right front wheel final cases 10a.

[0018] Further, on the rear side of the main frame 15, rear wheel gear cases 11a are attached to both the left and right sides of the rear frame 22 provided in the lateral direction (see FIG. 2), and the rear wheels 11 are respectively attached to the left and right rear axles 11b that protrude outward from the rear wheel gear cases 11a.

[0019] In addition, on the upper part of the rear frame 22, left and right link support frames 23 for supporting the lifting link mechanism 3 project upward. On the lower side of the left and right link support frames 23 and between the left and right, a pair of left and right lower link arms 24 are provided. A lifting cylinder 25 that operates by hydraulic pressure is provided between the left and right of the left and right lower link arms 24.

[0020] An upper link arm 26 is provided above the lifting cylinder 25, forming a lifting link mechanism 3, which is a parallel link mechanism. The left and right lower link arms 24, each with one end connected to the vehicle body 2, the lifting cylinder 25, and the other end of the upper link arm 26 are mounted on the front of the seedling planting section 4.

[0021] Furthermore, an engine 30 is mounted on the main frame 15. The rotational power of the engine 30 is transmitted to the transmission case 13 via a belt drive 21 and an HST 14. The rotational power transmitted to the transmission case 13 is shifted by a sub-transmission mechanism 16 inside the transmission case 13, and then divided into driving power and externally extracted power.

[0022] Furthermore, the rotational power of the engine 30 is transmitted to a hydraulic pump (not shown). The hydraulic pressure generated by the hydraulic pump is supplied to the HST 14, the power steering mechanism 88 of the steering wheel 35 (see Figure 3), the lifting cylinder 25, and the like.

[0023] External power extracted from the rotational power transmitted to the transmission case 13 is transmitted to the planting clutch case 27 located at the rear of the vehicle body 2, and from the planting clutch case 27 to the seedling planting unit 4 via the planting transmission shaft 67.

[0024] Meanwhile, the left and right drive shafts 42 are provided at the rear of the transmission case 13. The rotational power from the engine 30 is transmitted to the left and right rear wheel gear cases 11a via the transmission case 13 and the drive shafts 42.

[0025] Furthermore, a side clutch 44 (see Figure 3) for switching power transmission to the left and right drive shafts 42 is positioned upstream of the left and right drive shafts 42 in the transmission direction. As shown in Figure 1, a side clutch pedal 43a for operating the left and right side clutches 44 is provided on one side of the front lower part of the driver's seat 41.

[0026] By depressing the side clutch pedal 43a on the inside of the turn, disengaging the side clutch 44, and then operating the steering wheel 35 to turn, the drive rotation of the inner rear wheel 11 can be completely shut off.

[0027] A bonnet 39 is provided on the upper front of the vehicle body 2, with a control panel 38 for operating various parts positioned on top. The control panel 38 is equipped with a monitor 86 (see Figure 3), etc.

[0028] The bonnet 39 is also equipped with a steering wheel 35 for steering the vehicle body 2, a gear shift lever 36 (first control unit) for operating the HST 14 and seedling planting unit 4, and a sub-gear shift lever 37 for operating the sub-gear shift mechanism 16. When the gear shift lever 36 is operated, the vehicle body 2 can be switched between forward and reverse.

[0029] Furthermore, a front cover 40 that can be opened and closed is provided on the front side of the bonnet 39. Inside the front cover 40 are the fuel tank, battery, and an interlocking mechanism that rotates the left and right front wheels 10 and the lower parts of the left and right front wheel final cases 10a in response to the steering of the steering wheel 35. The front wheels 10 are, for example, steering wheels that turn in response to the steering of the steering wheel 35.

[0030] An engine cover 30a is provided behind the bonnet 39 and above the engine 30, covering the top and sides of the engine 30, and a cockpit 41 where the driver sits is provided on top of the engine cover 30a.

[0031] As shown in Figure 2, a seesaw switch 48 (second operating unit) is provided to the side of the cockpit 41, for example, to the left, which allows the vehicle speed of the vehicle body 2 to be set during automatic driving, as described later. The seesaw switch 48 is provided so that it can be easily operated by the operator seated in the cockpit 41. The seesaw switch 48 is provided so that it can be operated along the direction of travel of the vehicle body 2. The seesaw switch 48 is provided so that it can be operated in the front-rear direction. For example, the seesaw switch 48 is provided so that it can be tilted in the direction of travel of the vehicle body 2. The seesaw switch 48 may also be provided on the bonnet 39 or the like. The seesaw switch 48 may also be provided so that it can be operated in the up-down direction.

[0032] A fertilizer application device 5 is provided behind the cockpit 41, at the rear end of the main frame 15. The driving force for the fertilizer application device 5 is transmitted by a fertilizer transmission mechanism, which is provided so as to face the fertilizer application device 5 from one side of the left and right rear wheel gear cases 11a.

[0033] On both the left and right sides of the lower part of the engine cover 30a and bonnet 39, a roughly horizontal floor step 33 is formed. As shown in Figure 2, the floor step 33 is partially lattice-shaped, so that, for example, if mud from the driver's shoes falls onto the floor step 33, the fallen mud will fall onto the field.

[0034] Furthermore, a rear step 330 is connected to the rear of the floor step 33, as shown in Figure 2. It is preferable that the surface of the rear step 330 be treated with an anti-slip finish, for example, by forming multiple protrusion patterns, to prevent feet from slipping during work.

[0035] Furthermore, on the front side of the vehicle body 2, and on both the left and right sides, there are spare seedling frames 50 on seedling frame support posts 51, each with multiple spare seedling trays 52 arranged at vertical intervals, allowing for the placement of seedlings to be replenished in the seedling planting section 4, as well as work materials such as fertilizer bags.

[0036] Furthermore, a seedling tank 53 for loading seedlings to be planted in the field is attached to the rear end of the lifting link mechanism 3, along with a sliding mechanism that allows it to slide in the left-right direction. The seedling tank 53 has vertically long seedling partition fences 54 arranged at predetermined intervals in the left-right direction. Below the seedling tank 53 is a seedling planting device 55 that scoops up the loaded seedlings and plants them in the field.

[0037] The seedling planting device 55 plants the same number of rows as the number of planting work rows separated by the seedling partition fence 54, i.e., 8 rows simultaneously. Four planting transmission cases 56 are arranged at intervals below the seedling tank 53, and planting rotary tools 57 are attached to both the left and right sides of the planting transmission cases 56, which rotate and pick up seedlings with planting rods 58 to plant in the field.

[0038] The fertilizer application device 5 has a fertilizer hopper 70 where fertilizer is stored, which is divided into the same number of sections as the number of work rows in the seedling planting section 4 (eight sections in the example shown in Figure 2). However, since an eight-section fertilizer hopper 70 is long in the left-right direction, it reduces the convenience of loading and unloading fertilizer. Therefore, a so-called side fertilizer application structure may be used, where sections divided into four sections are arranged on the left and right sides.

[0039] At the bottom of the fertilizer hopper 70, a dispensing device 71 is provided for each row to supply a set amount of fertilizer. Below the dispensing device 71, a ventilation duct 72 is provided in the left-right direction through which the airflow that moves the fertilizer passes. Below the dispensing device 71, a fertilizer hose 73 is provided to guide the fertilizer to the vicinity of the seedling planting position in the seedling planting section 4. In addition, a blower 74 is provided at one end of the ventilation duct 72, which is operated by an electric motor 76 to generate the airflow for conveying the fertilizer.

[0040] As shown in Figures 1 and 2, below the seedling planting section 4, a center float 62C that makes contact with and slides on the field surface, and two side floats 62L and 62R on each side are provided so as to be rotatable around an axis. Note that the center float 62C and the left and right side floats 62L and 62R are sometimes collectively referred to as float 62.

[0041] Furthermore, below the seedling planting section 4, in front of the float 62, a leveling rotor 63 is provided to smooth out any unevenness in the field surface. The leveling rotor 63 receives driving force from the rear wheel gear cases 11a on the left and right sides via rotor transmission shafts 63a.

[0042] Furthermore, as shown in Figure 1, line markers 65 are provided on both the left and right sides of the seedling planting unit 4. One of these markers touches the field surface, forming a groove that serves as a guide for travel in the next work row (next process). When one side of the line markers 65 touches the ground, the other side moves upward and apart. When the seedling planting unit 4 is raised during a turn, both sides move upward and apart. After the turn, when the seedling planting unit 4 is lowered, one side moves upward and the other side touches the ground.

[0043] Furthermore, as shown in Figures 1 and 2, a vertically elongated center mascot 66 is provided in the left-right center of the vehicle body 2 and in front of the bonnet 39. By aligning the center mascot 66 with the grooves formed in the field using the left and right line markers 65, it becomes possible to travel in accordance with the working position of the immediately preceding work row, thereby improving work accuracy and preventing the occurrence of non-work.

[0044] Depending on the soil type of the field, the guide lines formed by the left and right line markers 65 may quickly become buried, causing the indicator for moving straight to disappear. In such cases, it is advisable to use the left and right side markers 19, which are positioned in front of the left and right line markers 65. That is, by moving the left and right side markers 19 outwards and positioning them above the planted seedlings, it becomes possible to perform planting work in line with the planting of seedlings in the previous work row.

[0045] Furthermore, as shown in Figure 1, the seedling transplanter 1 is equipped with a position detection device 150 and an antenna 151.

[0046] The antenna 151 receives satellite signals, for example, from GPS (Global Positioning System) satellites. The antenna 151 is mounted, for example, on a mounting bracket 59 and positioned above the vehicle body 2.

[0047] The position detection device 150 detects the current position of the seedling transplanter 1. The position detection device 150 detects the position of the vehicle body 2 based on satellite signals received by the antenna 151. The position detection device 150 can detect the position of the vehicle body 2 by first positioning and second positioning. Second positioning has higher detection accuracy than first positioning. For example, first positioning is DGPS (Differential GPS) positioning. Second positioning is RTK-GPS (Real-time Kinematic GPS) positioning.

[0048] Next, the control system of the seedling transplanter 1 will be described with reference to Figure 3. Figure 3 is a block diagram showing the control system of the seedling transplanter 1 according to the first embodiment, centered on the control device 100. The seedling transplanter 1 is capable of controlling each part by electronic control and is equipped with a control device (hereinafter referred to as a controller) 100 that controls each part.

[0049] The controller 100 includes a processing unit with a CPU (Central Processing Unit), a storage unit with ROM (Read Only Memory) and RAM (Random Access Memory), and an input / output unit, all of which are connected to each other and capable of exchanging signals. The controller 100 may also be capable of communicating with external devices. External devices include server devices and terminal devices.

[0050] The memory unit stores computer programs and other data that control the seedling transplanter 1. The controller 100 performs its functions by reading the computer programs and other data stored in the memory unit.

[0051] The controller 100 is connected to actuators such as a throttle motor 80, hydraulic control valves 81 and 82, a planting clutch operating solenoid 83, a side clutch operating solenoid 84, an HST motor 85, a line drawing marker lifting motor 87, a steering motor 95, and a differential lock switching motor 96.

[0052] The throttle motor 80 increases or decreases the rotational speed of the engine 30's output shaft by operating a throttle that adjusts the intake volume of the engine 30. The hydraulic control valve 81 controls the extension and retraction of the lifting cylinder 25. The hydraulic control valve 82 controls the power steering mechanism 88. The power steering mechanism 88 changes the direction of the front wheels 10, which are the steering wheels of the vehicle body 2. The planting clutch operating solenoid 83 operates the planting clutch 27a.

[0053] The side clutch operating solenoid 84 operates the side clutch 44, which switches the power transmission state to the rear wheels 11 (see Figure 1). Note that a side clutch 44 is provided for each of the left and right rear wheels 11, and two side clutch operating solenoids 84 are provided, one for each side clutch 44.

[0054] The HST motor 85 changes the tilt angle of the swash plate of the HST14 by changing the rotation angle of the trunnion of the HST14. The steering motor 95 is a motor that drives the handle 35, which is a steering device that adjusts the amount of steering (steering angle) of the front wheels 10 (see Figure 1) when automatic turning control is performed. The steering motor 95 rotates the handle 35. The line marking marker lifting motor 87 lifts and lowers the line marking marker 65.

[0055] The differential lock switching motor 96 is a motor that switches the operation and deactivation of the differential lock mechanism 97 (hereinafter referred to as the differential lock mechanism), which rotates the left and right driving wheels, for example, the left and right front wheels 10, at the same rotational speed. When the differential lock mechanism 97 is engaged, the left and right driving wheels rotate at the same rotational speed.

[0056] The controller 100 is connected to a rotation speed sensor 90, a steering amount sensor 91, and a position detection device 150, among others. Two rotation speed sensors 90 are provided, one for each of the left and right rear wheels 11, and each detects the rotation speed of the left and right rear wheels 11. Alternatively, the rotation speed sensors 90 may also detect the rotation speed of the left and right front wheels 10.

[0057] The steering amount sensor 91 detects the steering angle of the steering wheel 35, which is part of the steering device. In other words, the steering amount sensor 91 detects the operating position of the steering wheel 35, that is, the amount of steering (steering angle) of the front wheels 10. The steering amount sensor 91 is mounted, for example, on an axis connected to the pitman arm. The steering angle is detected in both the left and right directions, with the value when the steering wheel 35 is in a preset straight-ahead position being used as the reference value (0 degrees). For example, the steering angle is detected in conjunction with the turning direction of the steering wheel 35.

[0058] Furthermore, the controller 100 receives signals as operation signals from the gear shift lever 36, the sub-gear shift lever 37, the autonomous driving selector switch 46, the planting unit lifting switch 47, and the seesaw switch 48, among others. At least one of these switches may be a button.

[0059] The autonomous driving selector switch 46 is a switch that switches whether or not to perform autonomous driving. Specifically, the autonomous driving selector switch 46 is a switch that switches the driving mode between manual driving mode and autonomous driving mode. Manual driving mode is a mode in which the vehicle is driven by the operator's manual operation. Autonomous driving mode is a mode in which the vehicle is driven automatically without the operator's manual operation. Autonomous driving mode includes a mode in which part of the driving is driven by the operator's manual operation.

[0060] Specifically, autonomous driving includes automatic driving, straight-line assist driving, and turning assist driving. Automatic driving is driving in which the vehicle body 2 moves along an automatic driving path set in the work area described later, without operator intervention, and plants in the field. Automatic driving is performed based on the position information of the vehicle body 2 detected by the second positioning system. For example, in automatic driving, the steering motor 95 and the like are controlled so that the vehicle body 2 moves along the automatic driving path based on the position information included in the automatic driving path and the position information of the vehicle body 2 detected by the second positioning system. The automatic driving path is set based on the size of the work area and the size of the seedling transplanter 1, etc. The automatic driving path may be set by the control device 100 or by an external device.

[0061] In automated driving mode, for example, when the vehicle body 2 reaches the planting end position on the automated driving path, the seedling planting unit 4 stops planting seedlings, the seedling planting unit 4 rises and enters a non-working state, and the vehicle body 2 automatically turns without operator intervention. Also in automated driving mode, for example, when the vehicle body 2 reaches the planting start position on the automated driving path, the seedling planting unit 4 lowers and enters a working state, and the seedling planting unit 4 begins planting seedlings.

[0062] Straight-line assist driving is a type of driving where the vehicle body 2 moves in the field without operator intervention, based on the direction of a reference line, and plants in the field. Straight-line assist driving is performed based on the direction of the vehicle body 2, which is determined by the position information of the vehicle body 2 detected by the first positioning, and the direction of the reference line. For example, if the vehicle body 2 is moving in the same direction as the direction of travel when the reference line was acquired, in straight-line assist driving, the steering motor 95 and the like are controlled so that the direction of the reference line and the direction of the vehicle body 2 match. The reference line is set, for example, during teaching driving, which will be described later.

[0063] Turn-assist driving is driving in which the steering motor 95 is controlled so that the direction of the vehicle body 2 is reversed. Turn-assist driving is performed based on the direction of the vehicle body 2, which is based on the position information of the vehicle body 2 detected by the first positioning, and the direction of the reference line. Turn-assist driving may also be performed based on the steering angle and the distance traveled by the vehicle body 2.

[0064] In turning-assisted driving, for example, when the vehicle body 2 reaches a predetermined planting completion position, the seedling planting unit 4 stops planting seedlings, the seedling planting unit 4 rises and enters a non-working state, and the vehicle body 2 automatically turns without operator intervention. The predetermined planting completion position is set, for example, by the distance traveled in the work process or by the position information of the vehicle body 2 obtained from the first positioning related to the work process. In turning-assisted driving, the seedling planting unit 4 may be entered into a non-working state and the vehicle body 2 may start turning in response to the operation of the planting unit lifting switch 47. Turning-assisted driving ends when the vehicle body 2 reaches a predetermined turning completion position.

[0065] When the autonomous driving switch 46 is "ON", the driving mode is set to autonomous driving mode. When the autonomous driving switch 46 is "OFF", the driving mode is set to manual driving mode. A switch for performing straight-line assist driving may also be provided. A switch for performing turning assist driving may also be provided.

[0066] The planting unit lifting switch 47 is a switch that toggles whether or not to raise or lower the seedling planting unit 4. The planting unit lifting switch 47 can be changed to the "up" and "down" positions.

[0067] When the planting unit lifting switch 47 is in the "up" position, the seedling planting unit 4 enters a non-working state where the seedling planting device 55 stops and the seedling planting unit 4 rises to a predetermined non-working position. When the planting unit lifting switch 47 is in the "down" position, the seedling planting unit 4 lowers to a predetermined working position (predetermined planting work position) and enters a working state where the seedling planting device 55 operates.

[0068] The controller 100 switches the driving mode between manual driving mode and autonomous driving mode in response to the operation of the autonomous driving switch 46.

[0069] Furthermore, the controller 100 receives information regarding the current position of the vehicle body 2 from the position detection device 150. The controller 100 executes an autonomous driving mode in which the vehicle body 2 automatically drives and performs tasks. In autonomous driving mode, the controller 100 controls the steering motor 95 (see Figure 3) while feeding back the steering amount of the front wheels 10 (see Figure 1) to operate the steering wheel 35 (see Figure 3).

[0070] As shown in Figure 4, when teaching driving is performed, where the robot travels along three sides La to Lc of the field by the operator's controls, the controller 100 sets the work area in which the autonomous driving mode is executed. Figure 4 is a diagram showing the method of setting the work area by teaching driving according to the first embodiment.

[0071] For example, when the work area setting button (not shown) is operated and driving begins, the position information of the vehicle body 2 is recorded as the starting point of edge La, and the position information of the vehicle body 2 during driving is recorded. Then, when the steering wheel 35 is turned by the operator by more than a predetermined turning angle, the endpoint of edge La is recorded, and edge La is set. In addition, the position information of the vehicle body 2 at the starting point of edge Lb is recorded. The predetermined turning angle is a value set in advance, and is an angle at which it can be determined that the vehicle body 2 has turned along the embankment.

[0072] Furthermore, after the vehicle body 2 has moved in a straight line, if the steering wheel 35 is turned by the operator by more than a predetermined turning angle, the endpoint of edge Lb is recorded and edge Lb is set. In addition, the position information of the vehicle body 2 at the starting point of edge Lc is recorded.

[0073] When the work area setting button is operated after the vehicle body 2 has moved in a straight line, the position information of the vehicle body 2 is recorded as the endpoint of edge Lc, and edge Lc is set. The work area is set when the three edges La to Lc are set. In teaching mode, seedlings are planted in the field by the seedling planting unit 4 when the vehicle body 2 is moving in a straight line. Teaching mode is an outer perimeter process in which planting work is performed along the outer perimeter of the field. The work area is the area in the field where seedlings are planted by the vehicle body 2 moving back and forth in a reciprocating process.

[0074] In a field where a work area has been defined, autonomous driving mode becomes available. For example, an automatic driving path is set within the work area. Also, when driving along a side Lc in the field, a reference line is acquired. For example, the planting start position on side Lc is set as point A. The planting end position on side Lc is set as point B. The line connecting points A and B is then set as the reference line. Furthermore, the orientation of the reference line is detected from the position information of points A and B.

[0075] Furthermore, point A may be set as the position where the vehicle 2 has traveled a predetermined distance (for example, 2m) after planting has started at edge Lc. Alternatively, point A may be set as the position where planting has been performed for a predetermined time (for example, 2 seconds) after planting has started at edge Lc. This allows point A to be set while avoiding, for example, water inlets or field entrances at the edge of the field. Additionally, point B may be set as the position where autonomous driving begins after planting is completed at edge Lc.

[0076] Alternatively, during planting along edge Lc, points may be acquired at predetermined intervals (e.g., 2m) of the planting run, and the approximation line of multiple points may be used as the reference line. Alternatively, during planting along edge Lc, points may be acquired at predetermined intervals (e.g., 2m) of the planting run, and the approximation line of multiple points may be used as the reference line.

[0077] Furthermore, even after the teaching run is completed and the work area has been set, if the running mode is manual running mode, the seedling transplanter 1 can be operated by the operator and transplant seedlings into the field.

[0078] Next, the autonomous driving control according to the first embodiment will be explained with reference to Figure 5. Figure 5 is a flowchart illustrating the autonomous driving control according to the first embodiment. Here, it is assumed that a work area is set and the autonomous driving changeover switch 46 is "ON", that is, the driving mode is autonomous driving mode.

[0079] The controller 100 determines whether or not the position of the vehicle 2 can be detected by the second positioning (S100). For example, the controller 100 determines that the position of the vehicle 2 can be detected by the second positioning if the received signal from the second positioning is above a predetermined level. The controller 100 determines that the position of the vehicle 2 cannot be detected by the second positioning if the received signal from the second positioning is below a predetermined level.

[0080] If the controller 100 can detect the position of the vehicle 2 by the second positioning (S100: Yes), it performs automatic driving (S101).

[0081] Next, the controller 100 determines whether the seesaw switch 48 has been operated (S102). If the seesaw switch 48 has been operated (S102: Yes), the controller 100 changes the speed of the vehicle 2 according to the operation of the seesaw switch 48 (S103). The controller 100 changes the speed of the vehicle 2 while maintaining automatic driving. For example, if the seesaw switch 48 is operated forward (tilted forward), the controller 100 increases the speed of the vehicle 2 and accelerates the vehicle 2. If the seesaw switch 48 is operated backward (tilted backward), the controller 100 decreases the speed of the vehicle 2 and decelerates the vehicle 2.

[0082] When the vehicle speed of the vehicle body 2 is changed by the seesaw switch 48, the minimum vehicle speed is a vehicle speed that can be detected by the second positioning, for example, 0.2 m / s. Also, when the seesaw switch 48 is operated continuously, that is, when the operation of the seesaw switch 48 is continued, the vehicle speed changes by one step every second. Furthermore, the distance at which the change in vehicle speed begins when the seesaw switch 48 is operated may be set by the operator.

[0083] The controller 100 terminates the current process if the seesaw switch 48 is not operated (S102: No).

[0084] If the controller 100 cannot detect the position of the vehicle body 2 by the second positioning (S100: No), it performs straight-line assist driving and turning assist driving based on the first positioning (S104). The controller 100 may perform at least one of straight-line assist driving and turning assist driving.

[0085] The controller 100 prioritizes detecting the position of the vehicle 2 using the second positioning method, and if it cannot detect the position of the vehicle 2 using the second positioning method, it uses the first positioning method to detect the position of the vehicle 2.

[0086] Furthermore, if the gear shift lever 36 is operated during autonomous driving, the controller 100 changes the driving mode from autonomous driving mode to manual driving mode.

[0087] The seedling transplanter 1 comprises a vehicle body 2, a gear shift lever 36, a seesaw switch 48, and a controller 100. The vehicle body 2 has a driver's seat 41 where an operator can sit. The gear shift lever 36 switches the vehicle body 2 forward and backward. The seesaw switch 48 allows the vehicle speed of the vehicle body 2 to be set when the vehicle body 2 is in automatic mode. The controller 100 causes the vehicle body 2 to operate automatically. If the seesaw switch 48 is operated by the operator while the vehicle body 2 is in automatic mode, the controller 100 changes the vehicle speed of the vehicle body 2 while maintaining automatic mode.

[0088] As a result, the seedling transplanter 1 can perform automatic driving while the operator is seated in the cockpit 41. Furthermore, the operator can change the vehicle speed during automatic driving while seated in the cockpit 41. The seedling transplanter 1 can perform automatic driving without, for example, installing obstacle sensors to detect obstacles. Therefore, the seedling transplanter 1 can perform automatic driving at a lower cost.

[0089] The seedling transplanter 1 is equipped with a position detection device 150. The position detection device 150 can detect the position of the vehicle body 2 by first positioning and second positioning. The second positioning has higher detection accuracy than the first positioning. The controller 100 performs automatic driving based on the position of the vehicle body 2 detected by the second positioning, and if the position of the vehicle body 2 cannot be detected by the second positioning during automatic driving, it performs straight-line assist driving and turning assist driving based on the first positioning.

[0090] As a result, even when the seedling transplanter 1 cannot perform automatic driving using the second positioning system, it can plant seedlings while reducing the operator's input by performing straight-line assist driving and turning assist driving. In other words, even when the seedling transplanter 1 cannot perform automatic driving using the second positioning system, it can plant seedlings while reducing the operator's workload.

[0091] When the controller 100 is traveling along side Lc, which is the third side of the teaching run that travels along the three sides of the field ridge, it acquires a reference line for the straight-line assist run.

[0092] As a result, the seedling transplanter 1 can reliably acquire a reference line. Furthermore, the seedling transplanter 1 can accurately acquire a reference line along the ridge. Therefore, when the seedling transplanter 1 performs straight-line assist driving, it can accurately transplant seedlings into the field.

[0093] The seesaw switch 48 is positioned to be operated along the direction of travel of the vehicle body 2. This allows the operator to change the speed of the vehicle body 2 by operating the seesaw switch 48 without mistakenly performing the acceleration and deceleration intended by the operator. In other words, the seedling transplanter 1 can accurately accelerate and decelerate during automatic travel in accordance with the operator's intentions.

[0094] When the seedling transplanter 1 is automatically traveling, if work materials, such as seedlings or fertilizer, are being replenished, it may travel to the ridge in response to the operation of the seesaw switch 48. For example, when the vehicle body 2 is near the point where it is about to start turning during automatic travel, and the seesaw switch 48 is operated to the side that accelerates the vehicle body 2, the vehicle body 2 will travel straight without turning and travel to the ridge. In other words, when work materials are being replenished to the vehicle body 2 during automatic travel, the vehicle body 2 will travel to the ridge in response to the operation of the seesaw switch 48 and perform ridge mobilization. The seedling transplanter 1 stops the vehicle body 2, for example, when the seesaw switch 48 is no longer operated outside the work area. In addition, when the seesaw switch 48 is operated outside the work area, the vehicle speed of the vehicle body 2 may be set to a predetermined low speed. Also, for example, the seedling transplanter 1 reverses when the seesaw switch 48 is operated to the deceleration side from a stopped state of the vehicle body 2. Then, once the seedling transplanter 1 returns to the work area, it begins to turn automatically.

[0095] As a result, the seedling transplanter 1 can travel to a ridge where work materials are replenished based on the operation of the seesaw switch 48 while automatically traveling. The seedling transplanter 1 can replenish work materials while maintaining the vehicle body 2 in an automatic travel state.

[0096] The controller 100 may acquire a reference line based on the position of the vehicle body 2 detected during automatic driving. That is, the controller 100 may acquire a reference line using the azimuth angle of the work process (round trip process) of the path based on the position of the vehicle body 2 detected by the second positioning. If the position of the vehicle body 2 cannot be detected by the second positioning during automatic driving, the controller 100 controls the steering motor 95 so that the azimuth of the reference line obtained during automatic driving matches the azimuth of the vehicle body 2, and performs straight-line assist driving.

[0097] As a result, the seedling transplanter 1 can reliably acquire a reference line. Furthermore, the seedling transplanter 1 can accurately acquire a reference line along the path during automatic driving. Therefore, when the seedling transplanter 1 performs straight-line assist driving, it can accurately transplant seedlings into the field.

[0098] For example, if a reference line is acquired when traveling along edge Lc during teaching, and the vehicle moves to the ridge to replenish materials during automatic driving, the reference line acquired when traveling along edge Lc may be erased, and a new reference line may be acquired based on the position of the vehicle 2 detected during automatic driving.

[0099] When stopping the traveling vehicle 2, the seedling transplanter 1 may be controlled to stop at the target position after a predetermined stopping time, for example, 5 seconds, following the start of deceleration. The time at which deceleration begins may be configurable.

[0100] When the seedling transplanter 1 starts moving forward, it may be controlled to reach a set vehicle speed in a predetermined time, for example, 3 seconds. This suppresses sudden acceleration of the seedling transplanter 1 and improves the safety of the operator. The predetermined time may be configurable.

[0101] The seedling transplanter 1 calculates the slip ratio from the vehicle speed calculated from the change in the position of the traveling vehicle body 2 detected by the position detection device 150 and the vehicle speed calculated from the rotation speed sensor 90. If the slip ratio is a predetermined slip ratio, for example 0.8 or less, the degree of acceleration or deceleration, such as by operating the seesaw switch 48, may be increased.

[0102] The seedling transplanter 1 detects the value of the auto-accelerator dial, and if the dial value exceeds a set threshold, it may reduce the degree of acceleration or deceleration, for example, by operating the seesaw switch 48. This allows the seedling transplanter 1 to smooth out changes in vehicle speed when the engine speed is increasing, thereby improving the driver's comfort. (Second Embodiment) Next, the seedling transplanter 1 according to the second embodiment will be described. Here, we will describe the parts that differ from the first embodiment. Descriptions of the same configuration as the first embodiment will be omitted. The seedling transplanter 1 according to the second embodiment is equipped with an accelerator pedal 49 (second operating part) instead of a seesaw switch 48, as shown in Figure 6. Figure 6 is a side view showing the seedling transplanter 1 according to the second embodiment.

[0103] The accelerator pedal 49 is located at the front lower part of the driver's seat 41. The accelerator pedal 49 is designed to be operated by the driver's foot. When the vehicle 2 is driving automatically, the accelerator pedal 49 can set the vehicle speed of the vehicle 2 while it is driving automatically. As shown in Figure 7, the accelerator pedal 49 is equipped with a limit switch 60. The limit switch 60 detects whether or not the accelerator pedal 49 is pressed. The limit switch 60 turns ON when the accelerator pedal 49 is pressed and OFF when the accelerator pedal 49 is not pressed. Figure 7 is a block diagram showing the control system centered on the controller 100 of the seedling transplanter 1 according to the second embodiment.

[0104] Next, the autonomous driving control according to the second embodiment will be explained with reference to Figure 8. Figure 8 is a flowchart illustrating the autonomous driving control according to the second embodiment. Here, it is assumed that a work area is set and the autonomous driving changeover switch 46 is "ON", that is, the driving mode is autonomous driving mode.

[0105] The controller 100 determines whether or not the position of the vehicle 2 can be detected by the second positioning (S100).

[0106] If the controller 100 can detect the position of the vehicle 2 by the second positioning (S100: Yes), it performs automatic driving (S101).

[0107] Next, the controller 100 determines whether the limit switch 60 is ON or not (S200). That is, the controller 100 determines whether the accelerator pedal 49 is pressed or not. If the limit switch 60 is ON (S200: Yes), that is, if the accelerator pedal 49 is pressed, the controller 100 determines whether the vehicle speed of the vehicle 2 is at its maximum speed (S201). The maximum speed is the maximum speed in automatic driving and is a preset speed.

[0108] If the speed of the vehicle 2 is not at its maximum speed (S201: No), the controller 100 increases the speed of the vehicle 2 and accelerates the vehicle 2 (S202).

[0109] If the speed of the vehicle body 2 is at its maximum speed (S201: Yes), the controller 100 maintains the speed of the vehicle body 2 at its maximum speed (S203).

[0110] When the limit switch 60 is OFF (S200: No), that is, when the accelerator pedal 49 is not pressed, the controller 100 sets the vehicle speed of the vehicle 2 to a predetermined speed. The predetermined speed is the speed set as the normal speed in automatic driving. For example, the predetermined speed is the speed corresponding to the second forward gear. For example, when the accelerator pedal 49 is released after being pressed, the controller 100 reduces the vehicle speed of the vehicle 2 and decelerates the vehicle 2.

[0111] Furthermore, in step S202, if the vehicle body 2 is accelerated, the vehicle speed of the vehicle body 2 will be greater than the predetermined vehicle speed.

[0112] If the controller 100 cannot detect the position of the vehicle body 2 by the second positioning (S100: No), it performs straight-line assist driving and turning assist driving based on the first positioning (S104). The controller 100 may perform at least one of straight-line assist driving and turning assist driving.

[0113] The seedling transplanter 1 is equipped with an accelerator pedal 49 that can be operated by the operator's foot, which allows the vehicle speed of the vehicle body 2 to be set when the vehicle body 2 is moving automatically.

[0114] This allows the operator to change the vehicle speed of the vehicle 2 while maintaining autonomous driving by operating the accelerator pedal 49 with their foot. Therefore, the operator can easily adjust the vehicle speed of the vehicle 2 while it is driving autonomously.

[0115] The seedling transplanter 1 is equipped with a limit switch 60 that detects whether or not the accelerator pedal 49 is pressed. When the accelerator pedal 49 is pressed during automatic driving, the controller 100 accelerates the vehicle 2. When the vehicle speed of the vehicle 2 reaches its maximum speed during automatic driving, the controller 100 maintains the vehicle speed of the vehicle 2 at the maximum speed.

[0116] As a result, the seedling transplanter 1 can change its vehicle speed during automatic driving according to the detection result from the limit switch 60. Therefore, the operator can easily adjust the vehicle speed of the vehicle 2 during automatic driving. In addition, the seedling transplanter 1 can prevent the vehicle speed of the vehicle 2 from becoming too high during automatic driving, thereby improving the safety of the operator.

[0117] When the accelerator pedal 49 is pressed during automatic driving, the controller 100 decelerates the vehicle body 2 and then maintains the vehicle speed of the vehicle body 2 at a predetermined speed.

[0118] As a result, when the accelerator pedal 49 is not pressed during automatic driving, the seedling transplanter 1 can continue automatic driving while decelerating the vehicle body 2 in accordance with the operator's input. In other words, the seedling transplanter 1 can drive automatically at the vehicle speed intended by the operator.

[0119] If the accelerator pedal 49 changes from being pressed to not being pressed while the vehicle is driving automatically, the controller 100 may decelerate the vehicle 2 and then stop the vehicle 2.

[0120] As a result, the seedling transplanter 1 can stop the vehicle body 2 according to the operator's intention when the operator stops pressing the accelerator pedal 49 while the machine is automatically moving.

[0121] The seedling transplanter 1 may be equipped with a potentiometer on the accelerator pedal 49. The potentiometer detects the amount the operator presses down on the accelerator pedal 49. The controller 100 accelerates, decelerates, or maintains the vehicle speed of the vehicle body 2 during automatic driving, according to the amount the accelerator pedal 49 is pressed down on, as detected by the potentiometer.

[0122] The seedling transplanter 1 may be equipped with a brake pedal, and a potentiometer may be provided on the brake pedal. The potentiometer detects the amount the brake pedal is pressed. The controller 100 accelerates, decelerates, or maintains the vehicle speed of the vehicle body 2 during automatic driving, according to the amount the brake pedal is pressed as detected by the potentiometer.

[0123] The seedling transplanter 1 may also perform furrowing of the vehicle body 2 for material replenishment by operating the accelerator pedal 49. In this case, the controller 100 controls the vehicle speed of the vehicle body 2 according to the amount the accelerator pedal 49 is pressed.

[0124] The seedling transplanter 1 may also be equipped with a seesaw switch 48 and an accelerator pedal 49.

[0125] The seedling transplanter 1 may be equipped with a center mascot lamp. Before starting, the seedling transplanter 1 flashes the green center mascot lamp several times to notify the operator of the start. Before accelerating, the seedling transplanter 1 flashes the green center mascot lamp several times to notify the operator of the acceleration. Before decelerating, the seedling transplanter 1 flashes the red center mascot lamp several times to notify the operator of the deceleration. Before the vehicle body 2 stops, the seedling transplanter 1 flashes the red center mascot lamp several times to notify the operator of the vehicle body 2 stopping. In addition to flashing the mascot lamp, the seedling transplanter 1 may also notify the operator by sounding a buzzer. The buzzer may be provided in front of and behind the cockpit 41. For example, when the vehicle body 2 starts or accelerates, the front buzzer sounds. Also, when the vehicle body 2 decelerates or stops, the rear buzzer sounds.

[0126] The seedling transplanter 1 may also detect soil fertility. If the soil fertility is lower than a preset standard value, the seedling transplanter 1 increases the amount of seedlings it takes. Conversely, if the soil fertility is higher than the standard value, the seedling transplanter 1 decreases the amount of seedlings it takes.

[0127] The seedling transplanter 1 may be configured so that the operator can set the planting depth using the monitor 86 depending on the soil fertility. The seedling transplanter 1 may also be configured so that the planting depth is not adjusted based on soil fertility using the monitor 86. The seedling transplanter 1 may also be configured so that the amount of seedlings harvested is not adjusted based on soil fertility using the monitor 86.

[0128] The seedling transplanter 1 may, when the control of planting depth based on soil fertility is released by the monitor 86, adjust to the amount of seedlings to be picked up set by the operator.

[0129] The seedling transplanter 1 may adjust the amount of seedlings to be picked by changing the amount based on the average soil fertility of the section over which the vehicle 2 has traveled a certain distance. The seedling transplanter 1 may also adjust the planting depth by changing the planting depth by changing the amount based on the average soil fertility of the section over which the vehicle 2 has traveled a certain distance.

[0130] The seedling transplanter 1 may control the amount of seedlings taken while variable fertilization control is being performed. The seedling transplanter 1 may also control the planting depth while variable fertilization control is being performed.

[0131] If the seedling transplanter 1 does not control the amount of seedlings to be taken based on soil fertility, it may control the amount of seedlings to be taken to the set seedling amount position. If the seedling transplanter 1 does not control the planting depth based on soil fertility, it may control the planting depth to the set planting depth position.

[0132] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0133] 1. Seedling transplanter (work vehicle) 2. Running vehicle 4 Seedling planting department 35 Handle 36. Gear shift lever (first operating part) 41 Cockpit (driver's seat) 48. Seesaw switch (second operating section) 49. Accelerator pedal (second control unit) 60 Limit Switch 100 Controllers (control devices) 150 Position detection device

Claims

1. A first operating means for switching the forward and reverse movement of the vehicle, When the vehicle is in automatic motion, a second operating means is provided that can set the vehicle speed of the vehicle during automatic motion, A control device that causes the aforementioned vehicle body to perform automatic driving. Equipped with, The control device, when the second operating means is operated during automatic driving, While maintaining the aforementioned automatic driving, the vehicle speed of the vehicle is changed. The system includes a position detection device capable of detecting the position of the vehicle body by first positioning and second positioning, The second positioning method has higher detection accuracy than the first positioning method. The control device is Based on the position of the vehicle detected by the second positioning method, automatic driving is performed. A work vehicle capable of performing at least one of the following: straight-line assist driving and turning assist driving based on the first positioning, if the position of the vehicle body cannot be detected by the second positioning during automatic driving.

2. The work vehicle according to claim 1, wherein when work materials are replenished to the vehicle body while it is automatically traveling, the vehicle body travels to the ridge in response to the operation of the second operating means.

3. The work vehicle according to claim 2, wherein the control device acquires a reference line for the straight-line assist driving using the azimuth angle of the round-trip process of the path based on the position of the driving vehicle body detected by the second positioning.

4. The control device, when traveling along a predetermined edge during teaching travel along the edge of a field ridge, acquires a reference line for the straight-line assist travel, as described in claim 3.

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