Work vehicles

Abstract

To provide a work vehicle that prevents deviations in the starting position of seedling planting. [Solution] A work vehicle according to one embodiment comprises a vehicle body, a seedling planting unit attached to the vehicle body, a rotation speed sensor for detecting the rotation speed of the wheels of the vehicle body, a steering amount sensor for detecting the amount of steering of the steering device of the vehicle body, and a control device for controlling the raising and lowering and operating state of the seedling planting unit, wherein the control device calculates the orientation of the vehicle body based on the rotation speed and the amount of steering when the vehicle body turns, and lowers the seedling planting unit to the planting position when the calculated orientation of the vehicle body satisfies predetermined conditions, based on the orientation of the vehicle body when the planting work by the seedling planting unit is completed.

Description

Technical Field

[0004] ,

[0006] , , , ,

[0005] , , , ,

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

Background Art

[0002] Conventionally, there is known a work vehicle that raises and lowers a seedling planting part in response to a steering operation and controls the operating state of the seedling planting part during turning (see, for example, Patent Document 1).

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described work vehicle, when the rotational speed of the rear wheel on the inner side of turning reaches a predetermined rotational speed during turning, the seedling planting part is lowered to start planting by the seedling planting part. Therefore, depending on the turning situation, there is a possibility that the start position of planting by the seedling planting part may deviate from the desired position.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a work vehicle that suppresses deviation of the start position of seedling planting.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, a work vehicle (1) according to one embodiment comprises a vehicle body, a seedling planting unit attached to the vehicle body, a rotation speed sensor for detecting the rotation speed of the wheels of the vehicle body, a steering amount sensor for detecting the amount of steering of the steering device of the vehicle body, and a control device for controlling the raising and lowering and operating state of the seedling planting unit, wherein the control device calculates the orientation of the vehicle body based on the rotation speed and the amount of steering when the vehicle body turns, and lowers the seedling planting unit to the planting position when the calculated orientation of the vehicle body satisfies predetermined conditions, based on the orientation of the vehicle body when the planting work by the seedling planting unit is completed. [Effects of the Invention]

[0007] According to one embodiment, it is possible to suppress deviations in the starting position for planting seedlings. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a side view showing a work vehicle. [Figure 2] Figure 2 is a plan view showing the work vehicle. [Figure 3] Figure 3 is a block diagram showing the control system, centered around the control device of the seedling transplanter. [Figure 4] Figure 4 shows a method for setting the work area by teaching travel according to an embodiment. [Figure 5] Figure 5 is a flowchart illustrating the turning control according to the embodiment. [Modes for carrying out the invention]

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

[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 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 operator (also called the worker) 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] In this embodiment, the work vehicle 1 is described as a ride-on seedling transplanter 1 equipped with a seedling planting unit 4 as a work machine, which 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 for planting seedlings in the field, via a lifting link mechanism 3 on the rear side of the traveling vehicle body 2.

[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 vehicle body 2 is a four-wheel drive vehicle equipped with left and right front wheels 10 and rear wheels 11, which are both wheels and drive wheels. On the front side of the main frame 15 that constitutes the vehicle body frame of the vehicle body 2, there is a transmission case 13 that transmits driving force to the seedling planting unit 4 and the like, and a hydraulic continuously variable transmission 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 14 is a hydrostatic continuously variable transmission known as a so-called HST (Hydro Static Transmission). Hereinafter, the case where the continuously variable transmission is the HST 14 will be described.

[0017] Inside the transmission case 13, a sub-transmission mechanism 16 is provided 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. Front-wheel final cases 10a are provided on the left and right sides of the transmission case 13, and front wheels 10 are attached to the left and right front axles 10b that project outward from front-wheel support portions capable of changing the steering direction of the left and right front-wheel final cases 10a.

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

[0019] Also, on the upper part of the rear frame 22, left and right link support frames 23 that support 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 hydraulically 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, and the lifting link mechanism 3, which is a parallel link mechanism, is constituted. Note that the other end sides of the left and right lower link arms 24, the lifting cylinder 25, and the upper link arm 26, each of which is connected to the traveling vehicle body 2 at one end, are attached to the front part of the seedling planting part 4.

[0021] In addition, 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 the belt transmission device 21 and the HST 14. The rotational power transmitted to the transmission case 13 is shifted by the sub-shifting mechanism 16 in the transmission case 13 and then divided into traveling power and externally extracted power.

[0022] In addition, 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 (see FIG. 3) of the steering wheel 35, the lifting cylinder 25, etc.

[0023] The externally extracted power taken from the rotational power transmitted to the transmission case 13 is transmitted to the planting clutch case 27 provided at the rear of the traveling vehicle body 2, and is transmitted from the planting clutch case 27 to the seedling planting section 4 by the planting transmission shaft 67.

[0024] On the other hand, 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] Note that a side clutch 44 (see FIG. 3) for engaging and disengaging the power transmission to the left and right drive shafts 42 is arranged on the upstream side in the transmission direction from the left and right drive shafts 42. As shown in FIG. 1, a side clutch pedal 43a for operating the left and right side clutches 44 is provided at the lower front side of the driver's seat 41 and on one side of the left and right.

[0026] When the side clutch pedal 43a on the inside of the turn is depressed to disengage the side clutch 44 and then the steering wheel 35 is operated to perform a turning travel, the driving rotation of the rear wheel 11 on the inside of the turn can be completely blocked.

[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 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] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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 for sliding it in the left-right direction. Long seedling partition fences 54 are arranged on the seedling tank 53 at predetermined intervals in the left-right direction. Below the seedling tank 53 is a seedling planting device 55 for scooping up the loaded seedlings and planting them in the field.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Furthermore, as shown in Figure 1, the seedling transplanter 1 is equipped with a position detection device 150 and an antenna 151.

[0045] Antenna 151 receives satellite signals, for example, from GPS (Global Positioning System) satellites. Antenna 151 is mounted, for example, on a mounting bracket 59 and positioned above the vehicle body 2. An inertial positioning unit 152 (IMU: Internal Measurement Unit) is provided on Antenna 151. The inertial positioning unit 152 can detect the acceleration of the vehicle body 2, as well as the tilt of the vehicle body 2.

[0046] 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 the satellite signal received by the antenna 151.

[0047] 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, 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.

[0048] The controller 100 is equipped with a processing unit including a CPU (Central Processing Unit), a storage unit including ROM (Read Only Memory) and RAM (Random Access Memory), and an input / output unit, all of which are connected to each other and can exchange signals.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] The controller 100 is connected to detection devices such as a rotation speed sensor 90, a steering amount sensor 91, a position detection device 150, and an inertial positioning unit 152. 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.

[0056] 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.

[0057] Furthermore, the controller 100 receives signals as operation signals from the gear shift lever 36, sub-gear shift lever 37, autonomous driving switch 46, planting unit lifting switch 47, automatic planting switch 49, automatic straight-ahead switch 45, and automatic turning switch 48, among others. At least one of these switches may be a button.

[0058] 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 (automatic 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.

[0059] For example, 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. When the autonomous driving switch 46 is turned "ON", the automatic straight-ahead switch 45 and the automatic turning switch 48 are also turned "ON". Note that even if the automatic straight-ahead switch 45 and the automatic turning switch 48 are turned "ON", they can be changed to "OFF" by the operator.

[0060] 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.

[0061] 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.

[0062] The automatic planting changeover switch 49 is a switch that automatically switches whether the seedling planting unit 4 is in a non-working state or a working state in accordance with the turning of the vehicle body 2. When the automatic planting changeover switch 49 is "ON", the seedling planting unit 4 is in a non-working state when the vehicle body 2 starts to turn. That is, when the automatic planting changeover switch 49 is "ON", the seedling planting device 55 stops and the seedling planting unit 4 rises to a predetermined non-working position when the vehicle body 2 starts to turn. Also, when the automatic planting changeover switch 49 is "ON", the seedling planting unit 4 is in a working state when the vehicle body 2 finishes turning. That is, when the automatic planting changeover switch 49 is "ON", the seedling planting unit 4 is lowered to a predetermined working position and the seedling planting device 55 is in a working state when the vehicle body 2 finishes turning. Details of the control when the automatic planting changeover switch 49 is "ON" will be described later.

[0063] The automatic straight-ahead switch 45 is a switch that toggles whether or not automatic straight-ahead driving is enabled. When the automatic straight-ahead switch 45 is set to "ON", the driving assist function described later is enabled, and automatic straight-ahead driving becomes possible. When the automatic straight-ahead switch 45 is set to "OFF", the driving assist function is disabled, and automatic straight-ahead driving becomes impossible.

[0064] The automatic turning switch 48 is a switch that toggles whether or not automatic turning is enabled. When the automatic turning switch 48 is set to "ON", the turning assist function described later is enabled, and automatic turning becomes possible. When the automatic turning switch 48 is set to "OFF", the turning assist function is disabled, and automatic turning becomes impossible. When the automatic turning switch 48 is set to "OFF", automatic turning will not be performed even if the conditions for performing automatic turning are met. Note that when the automatic turning switch 48 is set to "ON", the automatic planting switch 49 is also set to "ON".

[0065] 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, the automatic straight-ahead driving switch 45, and the automatic turning switch 48.

[0066] Furthermore, the controller 100 receives information from the position detection device 150 regarding the current position of the vehicle body 2. The controller 100 then executes an autonomous driving mode in which the vehicle body 2 automatically drives and performs tasks.

[0067] Furthermore, various information is input to the controller 100 from the remote control device 170 (hereinafter referred to as "remote control"). For example, the controller 100 receives various information from the remote control 170 via the receiver 180 (see Figure 1). The receiver 180 is, for example, mounted on a mounting bracket 59 (see Figure 1) and positioned above the front of the vehicle body 2. Note that multiple receivers 180 may be provided. The mounting bracket 59 is attached to the vehicle body 2.

[0068] The remote control 170 can remotely operate the seedling transplanter 1. The remote control 170 may also be a terminal device such as a smartphone. The remote control 170 transmits control signals in response to the operator's operations. The remote control 170 is connected to the controller 100 via short-range wireless communication such as Wi-Fi (registered trademark) or BLE (Bluetooth (registered trademark) Low Energy), but is not limited to this, and may be connected via a communication network in addition to or instead of short-range wireless communication.

[0069] Multiple remote controls 170 may be provided. That is, the controller 100 may be able to obtain location information from multiple remote controls 170.

[0070] Here, we will describe the autonomous driving (automatic driving) of the seedling transplanter 1 in the field. The controller 100 has an autonomous driving mode (automatic driving mode) in which it 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). The autonomous driving mode includes an automatic straight driving mode and an automatic turning mode.

[0071] The automatic straight-line mode is a mode in which the steering motor 95 is controlled so that the vehicle body 2 moves in a straight line along a preset straight path. In the automatic straight-line mode, the vehicle body 2 moves in a straight line without operator intervention while the seedling planting unit 4 plants seedlings in the field. In other words, the driving assist function, which automatically moves the vehicle body 2 in a straight line while transplanting seedlings in the field, is activated and executed.

[0072] The automatic turning mode is a mode in which, when the vehicle body 2 reaches a predetermined planting completion position, the seedling planting unit 4 stops planting seedlings, and the steering motor 95 is controlled to turn the vehicle body 2 along a preset turning path. The predetermined planting completion position is set by, for example, the distance traveled in the work process or position information related to the work process.

[0073] In automatic turning mode, for example, the seedling planting unit 4 is raised and put into a non-working state, and the vehicle body 2 automatically turns without operator intervention. In other words, the turning assist function, which turns the vehicle body 2 without the seedling planting unit 4 planting seedlings, is activated and executed.

[0074] As shown in Figure 4, the work area in which the autonomous driving mode is executed is set by performing a teaching drive, in which the operator drives along three sides of the field from La to Lc. Figure 4 is a diagram showing the method of setting the work area by teaching drive according to the embodiment.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] In fields where a work area has been defined, autonomous driving mode becomes available. For example, in a field, it is possible to automatically drive in a straight line along a straight driving path parallel to side La or side Lc. Automatic turning is also possible when turning near the ridge on the side of side Lb. When turning near the ridge on a side of the field that was not covered during teaching, i.e., the side opposite side Lb, turning can be controlled by remote control. Automatic turning may also be performed when turning near the ridge on a side of the field that was not covered during teaching.

[0079] 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.

[0080] When the driving mode is manual driving mode and the seedling transplanter 1 is being driven by the operator, if the automatic straight-line switching switch 45 is turned "ON", the seedling transplanter 1 will perform automatic straight-line driving. In other words, the seedling transplanter 1 can perform the driving assist function even when the driving mode is manual driving mode.

[0081] Furthermore, when the driving mode is manual driving mode and the seedling transplanter 1 is being driven by the operator, if the automatic turning switch 48 is turned "ON", the seedling transplanter 1 becomes capable of automatic turning. In other words, the seedling transplanter 1 can perform the turning assist function even when the driving mode is manual driving mode.

[0082] Next, the turning control according to the embodiment will be explained with reference to Figure 5. Figure 5 is a flowchart illustrating the turning control according to the embodiment. The turning control is performed when the automatic planting changeover switch 49 is "ON".

[0083] The controller 100 determines whether the vehicle body 2 has started turning (S100). Specifically, the controller 100 determines whether the steering angle detected by the steering amount sensor 91 is greater than or equal to a predetermined angle. The predetermined angle is a pre-set angle, which is the angle at which it can be determined that the vehicle body 2 has started turning from a state where it is moving straight. The predetermined angle is set relative to a reference value. If the steering angle detected by the steering amount sensor 91 is greater than or equal to the predetermined angle, the controller 100 determines that the vehicle body 2 has started turning. If the steering angle detected by the steering amount sensor 91 is less than the predetermined angle, the controller 100 determines that the vehicle body 2 has not started turning.

[0084] If the controller 100 determines that the vehicle body 2 has not started turning (S100: No), it terminates the current process.

[0085] If the controller 100 determines that the vehicle body 2 has started to turn (S100: Yes), it puts the seedling planting unit 4 into a non-working state (S101). The controller 100 stops the seedling planting device 55 and raises the seedling planting unit 4 to a predetermined non-working position. In other words, the controller 100 terminates the seedling planting in the process in which planting was being performed.

[0086] Next, the controller 100 calculates the direction of the vehicle body 2 (S102). The controller 100 calculates the vehicle speed of the vehicle body 2 from the rotational speed detected by the rotational speed sensor 90. The controller 100 calculates the vehicle speed of the vehicle body 2 from the larger rotational speed of the left and right rear wheels 11. Specifically, the controller 100 calculates the vehicle speed of the vehicle body 2 from the rotational speed of the rear wheel 11 on the outside of the turn. Based on the calculated vehicle speed (m / s) and the steering angle (deg) detected by the steering amount sensor 91, the controller 100 calculates the angular velocity (deg / s) of the vehicle body 2 using the prediction formula shown in equation (1).

[0087] Angular velocity = 0.078 × steering angle × vehicle speed × slip ratio ... (1) The value "0.078" in equation (1) is set according to the type (size, etc.) of the seedling transplanter 1.

[0088] The controller 100 calculates the slip ratio from the difference between the predicted rotational speed of the inner rear wheel 11, which is predicted according to the steering angle, and the actual rotational speed of the inner rear wheel 11. The predicted rotational speed is calculated from the steering angle and the rotational speed of the outer rear wheel 11 when there is no slip. In other words, the predicted rotational speed is the predicted rotational speed of the inner rear wheel 11 when there is no slip. For example, the predicted rotational speed is calculated using a preset prediction formula based on the steering angle and the rotational speed of the outer rear wheel 11 when there is no slip. The predicted rotational speed may also be the rotational speed of the inner rear wheel 11 detected when there is no slip. The actual rotational speed is calculated based on the rotational speed detected by the rotational speed sensor 90.

[0089] The controller 100 calculates the orientation of the vehicle body 2 from the calculated angular velocity of the vehicle body 2. The controller 100 uses the orientation of the vehicle body 2 when it begins to turn as a reference (0 degrees) and calculates the orientation of the vehicle body 2 by integrating the angles based on the calculated angular velocity. For example, the controller 100 calculates the amount of change in angle per unit time (1 second) from the calculated angular velocity and calculates the orientation of the vehicle body 2 by integrating the calculated amount of change in angle. The orientation of the vehicle body 2 is the angle of the vehicle body 2 with respect to the reference.

[0090] Next, the controller 100 calculates the position of the seedling planting unit 4 (S103). The controller 100 calculates the position of the seedling planting unit 4 based on the calculated direction of the vehicle body 2 and the vehicle speed of the vehicle body 2. For example, the controller 100 estimates the position of the seedling planting unit 4 by integrating the direction of the vehicle body 2 and the vehicle speed of the vehicle body 2, and sets the estimated position as the position of the seedling planting unit 4.

[0091] The controller 100 may also calculate the position of the seedling planting unit 4 by the following method. The controller 100 calculates the cumulative value of the rotations of the left and right rear wheels 11 after the planting clutch 27a is released (disengaged), and estimates the position of the seedling planting unit 4 based on the cumulative value of the rotations. In other words, the controller 100 calculates the position of the seedling planting unit 4 by the cumulative value of the rotations of the left and right rear wheels 11.

[0092] Next, the controller 100 determines whether the orientation of the vehicle body 2 is in a predetermined direction (S104). The predetermined direction is a pre-set direction, for example, 180 degrees. The predetermined direction is the opposite direction to the direction at the position where the vehicle body 2 began turning, that is, the position where seedling planting was completed. If the controller 100 determines that the orientation of the vehicle body 2 is not in the predetermined direction (S104: No), it returns to step S102 and repeats the above process. If the controller 100 determines that the orientation of the vehicle body 2 is in the predetermined direction (S104: Yes), it lowers the seedling planting unit 4 to a predetermined working position (S105).

[0093] Next, the controller 100 determines whether the position of the seedling planting unit 4 is the seedling planting start position (S106). The controller 100 determines that the position of the seedling planting unit 4 is the seedling planting start position when the direction of the traveling vehicle body 2 is a predetermined direction and the accumulated value of the vehicle speed of the traveling vehicle body 2 is equal to or greater than a predetermined accumulated value. The predetermined accumulated value is a value set in advance.

[0094] Furthermore, when the controller 100 estimates the position of the seedling planting unit 4 based on the cumulative value of the rotational speed of the rear wheels 11, it determines that the position of the seedling planting unit 4 is the seedling planting start position when the orientation of the vehicle body 2 is a predetermined orientation and the cumulative value of the rotational speed is a predetermined turning constant plus a correction value. The correction value is the number of rotations corresponding to the distance traveled by the vehicle body 2 from the time the planting clutch 27a is released until the steering angle reaches a preset turning angle. The controller 100 determines whether the position of the seedling planting unit 4 has reached the seedling planting start position set by the completion of the planting work by the seedling planting unit 4 before turning.

[0095] If the controller 100 determines that the seedling planting unit 4 is not in the seedling planting start position (S106: No), it returns to step S103 and repeats the above process. Note that when returning to step S103 and repeating the process, steps S104 and S105 may be skipped. Also, in step S105, the seedling planting unit 4 may be held in a predetermined working position.

[0096] If the controller 100 determines that the seedling planting unit 4 is at the seedling planting start position (S106: Yes), it activates the seedling planting device 55 to put it into working mode (S107). As a result, the seedling transplanter 1 begins planting seedlings in the field.

[0097] The seedling transplanter 1 comprises a vehicle body 2, a seedling planting unit 4 attached to the vehicle body 2, a rotation speed sensor 90 for detecting the rotation speed of the rear wheels 11 of the vehicle body 2, a steering amount sensor 91 for detecting the steering angle of the handle 35 of the vehicle body 2, and a controller 100 for controlling the raising and lowering of the seedling planting unit 4 and the operating state of the seedling planting unit 4. When the vehicle body 2 turns, the controller 100 calculates the direction of the vehicle body 2 and the position of the seedling planting unit 4 based on the rotation speed and the steering angle. When the vehicle body 2 turns, the controller 100 calculates the angular velocity of the vehicle body 2 using a preset prediction formula based on the vehicle speed calculated based on the rotation speed and the steering angle, and calculates the direction of the vehicle body 2 based on the calculated angular velocity.

[0098] As a result, the seedling transplanter 1 can control the start of seedling planting by the seedling planting unit 4 based on the calculated orientation of the traveling vehicle 2. Therefore, the seedling transplanter 1 can suppress deviations in the starting position of seedling planting. For example, even if the travel of the traveling vehicle 2 is uneven when turning, the seedling transplanter 1 can suppress deviations in the starting position of seedling planting.

[0099] Furthermore, the rotation speed sensor 90 detects the rotation speeds of the left and right wheels of the vehicle body 2. The controller 100 calculates the angular velocity of the vehicle body 2 based on the vehicle speed calculated from the larger of the left and right rotation speeds, and the steering angle. For example, the controller 100 calculates the angular velocity of the vehicle body 2 based on the vehicle speed calculated from the rotation speed of the outer rear wheel 11 during a turn, and the steering angle.

[0100] This allows the seedling transplanter 1 to accurately calculate the angular velocity of the vehicle body 2 during turns. As a result, the seedling transplanter 1 can accurately calculate the direction of the vehicle body 2 during turns, thereby suppressing deviations in the starting position of seedling planting.

[0101] Furthermore, the controller 100 lowers the seedling planting unit 4 to a predetermined working position when the calculated direction of the vehicle body 2, based on the direction of the vehicle body 2 when the planting work by the seedling planting unit 4 is completed, reaches a predetermined direction.

[0102] As a result, even if the movement of the vehicle body 2 during turning is uneven, the timing of lowering the seedling planting unit 4 to the predetermined working position can be suppressed.

[0103] Furthermore, the controller 100 calculates the direction of the vehicle body 2 by integrating the calculated angular velocities of the vehicle body 2.

[0104] This allows the seedling transplanter 1 to accurately calculate the direction of the vehicle body 2 when turning, thereby suppressing deviations in the starting position of seedling planting.

[0105] Furthermore, the controller 100 calculates the position of the seedling planting unit 4 based on the orientation and speed of the vehicle body 2.

[0106] This allows the seedling transplanter 1 to accurately calculate the position of the seedling planting section 4 during rotation. As a result, the seedling transplanter 1 can suppress deviations in the starting position of seedling planting after rotation.

[0107] Furthermore, the controller 100 starts planting by the seedling planting unit 4 when the calculated direction of the traveling vehicle 2, based on the direction of the traveling vehicle 2 when the planting work by the seedling planting unit 4 is completed, reaches a predetermined direction, and the position of the seedling planting unit 4 reaches the starting position set by the completion of the planting work by the seedling planting unit 4 before turning.

[0108] This allows the seedling transplanter 1 to align the starting position of seedling planting by the seedling planting unit 4 with the ending position of planting before turning.

[0109] Furthermore, when the vehicle body 2 turns, the controller 100 calculates the slip ratio from the difference between the predicted rotational speed of the inner rear wheel 11, which is predicted according to the steering angle, and the actual rotational speed of the inner rear wheel 11. The predicted rotational speed is calculated from the steering angle and the rotational speed of the outer rear wheel 11 when there is no slip.

[0110] This allows the seedling transplanter 1 to accurately calculate the slip ratio that occurs during turning. Therefore, the seedling transplanter 1 can, for example, take the slip ratio into consideration during turning and start lowering the seedling planting unit 4 and planting by the seedling planting unit 4. Consequently, the seedling transplanter 1 can suppress deviations in the starting position of seedling planting.

[0111] The seedling transplanter 1 may reduce the predetermined direction as the angular velocity of the traveling vehicle 2, calculated using the prediction formula, increases. In other words, the seedling transplanter 1 will shorten the timing at which the seedling planting unit 4 lowers to the predetermined working position as the angular velocity of the traveling vehicle 2, calculated using the prediction formula, increases.

[0112] This allows the seedling transplanter 1 to adjust the timing of lowering the seedling planting unit 4 according to the angular velocity of the vehicle body 2. Therefore, the seedling transplanter 1 can optimize the timing of lowering the seedling planting unit 4.

[0113] The seedling transplanter 1 may detect the angular velocity and direction of the traveling vehicle 2 based on information obtained from the antenna 151. For example, the seedling transplanter 1 calculates the angular velocity of the traveling vehicle 2 from the time change of direction based on the direction information obtained from the antenna 151.

[0114] The seedling transplanter 1 prohibits the lowering of the seedling planting section 4 if its position is above a predetermined threshold. For example, if the seedling planting section 4 reaches the seedling planting start position (predetermined threshold) before the direction of the traveling vehicle 2 reaches a predetermined direction, the seedling transplanter 1 prohibits the lowering of the seedling planting section 4. For example, when turning in a field with a sloping ridge, the seedling transplanter 1 exits the field once before turning. In this case, there is a risk that the seedling planting section 4 will lower immediately after turning, before entering the field. Therefore, the seedling transplanter 1 prohibits the lowering of the seedling planting section 4 if its position is above a predetermined threshold. This prevents the seedling transplanter 1 from lowering the seedling planting section 4 in a location unsuitable for planting seedlings.

[0115] The seedling transplanter 1 may retain the calculated slip ratio until it is updated during the next turn. This allows the seedling transplanter 1 to use the slip ratio calculated during the turn while moving straight after the turn. Therefore, the seedling transplanter 1 can, for example, correct the amount of fertilizer applied based on the slip ratio and adjust the amount of fertilizer applied. The seedling transplanter 1 can also, for example, correct the amount of seedlings picked based on the slip ratio and adjust the amount of seedlings picked. Furthermore, the seedling transplanter 1 can, for example, correct the number of plants planted based on the slip ratio and adjust the spacing between plants during the straight-line process.

[0116] The seedling transplanter 1 may adjust the amount of fertilizer applied in conjunction with the field map. When the turning assist function is enabled, the seedling transplanter 1 may correct the turning and the starting position of seedling planting according to the angle between the working direction of the vehicle body 2 and the ridge on the map. For example, the seedling transplanter 1 calculates the angle at which the path currently being taken by the seedling transplanter 1 intersects with the field shape lines on the map, among the straight travel paths parallel to the straight line set by teaching travel (for example, side La (see Figure 4)). The seedling transplanter 1 corrects the turning and the starting position of seedling planting according to the calculated angle. As a result, the seedling transplanter 1 can automatically turn even on ridges with angles, that is, ridges that are not approximately perpendicular to the straight line set by teaching travel.

[0117] The seedling transplanter 1 identifies the ridges located in the current direction of travel of the vehicle body 2, based on the direction of travel of the vehicle body 2 and the direction of travel of the vehicle body 2 in a straight line set by teaching travel. The ridge to be identified is the closest ridge to the direction of travel from the current position of the vehicle body 2.

[0118] The seedling transplanter 1 adjusts the amount of backing up during an assisted back turn when automatically turning, and the planting start position, according to the angle between the working direction of the vehicle body 2 and the ridge on the map, the working width of the seedling transplanter 1, and the turning direction. For example, when the ridge narrows relative to the turning direction, the seedling transplanter 1 increases the amount of backing up and sets the planting start position of the seedlings towards the back (ridge side). Also, when the ridge widens relative to the turning direction, the seedling transplanter 1 decreases the amount of backing up and sets the planting start position of the seedlings towards the front (opposite side of the ridge).

[0119] The increase in the back distance coincides with the increase in the planting start position towards the front. Also, if the angle between the working direction of the vehicle 2 and the ridge on the map exceeds a predetermined threshold, the back distance and planting start position are determined with the threshold as the upper limit. Furthermore, if the angle between the working direction of the vehicle 2 and the ridge on the map is within a predetermined range of 90 degrees or more, the back distance and planting start position are not changed. The predetermined range is the range in which it can be determined that the angle between the working direction of the vehicle 2 and the ridge on the map is approximately 90 degrees.

[0120] The angle between the working direction of the vehicle body 2 and the ridge on the map is calculated, for example, by a terminal device and transmitted to the seedling transplanter 1 via wireless communication. When planting is in progress and seedlings are being planted, and after a certain period of time has elapsed, the seedling transplanter 1 updates the angle between the working direction of the vehicle body 2 and the ridge on the map that it had been holding. When automatic straight-line movement is being performed and after a certain period of time has elapsed, the seedling transplanter 1 may also update the angle between the working direction of the vehicle body 2 and the ridge on the map that it had been holding.

[0121] If the steering angle remains within a certain range from the straight-ahead position for a certain period of time, the seedling transplanter 1 may update the angle between the working direction of the vehicle body 2 and the ridge on the map, which it had been holding.

[0122] Furthermore, after updating the angle between the working direction of the vehicle body 2 and the ridge on the map, the seedling transplanter 1 does not update the angle between the working direction of the vehicle body 2 and the ridge on the map until it starts automatic turning.

[0123] The seedling transplanter 1 may be equipped with a constant-speed mode switch that switches the speed of the traveling vehicle 2 to a constant-speed mode. When the constant-speed mode switch is "ON", the controller 100 sets the maximum position of the speed shift lever 36 as the target constant-speed speed. The slow speed adjustment until reaching the maximum speed can be changed by the operator operating the speed shift lever 36.

[0124] 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]

[0125] 1. Seedling transplanter (work vehicle) 2. Running vehicle 4 Seedling planting department 10 Front Wheel 11 Rear wheels 27a Planting clutch 35. Steering wheel (steering device) 49 Automatic planting changeover switch 55 Seedling planting device 90 RPM sensor 91 Steering amount sensor 100 Controllers (control devices)

Claims

1. The vehicle body and The seedling planting unit attached to the vehicle body, A rotation speed sensor for detecting the rotation speed of the wheels of the vehicle body, A steering amount sensor for detecting the amount of steering of the steering device of the vehicle body, A control device that controls the raising and lowering and operating state of the seedling planting unit. Equipped with, The control device calculates the direction of the vehicle body based on the rotational speed and the steering amount when the vehicle body is turning. A work vehicle that lowers the seedling planting unit to the planting position when the calculated direction of the vehicle body, based on the direction of the vehicle body when the planting work by the seedling planting unit is completed, satisfies predetermined conditions.

2. The work vehicle according to claim 1, wherein the seedling planting unit starts planting work when the position of the seedling planting unit reaches the starting position set by the completion of planting work by the seedling planting unit before turning.

3. The control device is When the aforementioned vehicle body turns, Based on the vehicle speed calculated from the rotational speed and the steering amount, Using a pre-set prediction formula, the angular velocity of the moving vehicle is calculated. The rotation speed sensor detects the rotation speed of the left and right wheels of the vehicle body, respectively. The work vehicle according to claim 1 or 2, wherein the control device calculates the angular velocity based on the vehicle speed calculated from the larger of the left and right rotational speeds and the steering amount.

Images