Work vehicle

Abstract

To provide a work vehicle capable of planting seedlings along a field surface according to field conditions without using a sensor for directly sensing the field surface.SOLUTION: A work vehicle includes: a traveling vehicle body traveling in a field; a seedling planting part for planting seedlings in the field, the seedlings taken out from a seedling mat loaded on the rear part of the traveling vehicle body; and a lifting link mechanism for liftably / lowerably supporting the seedling planting part; a pitching angle sensor for detecting the pitching angle of the traveling vehicle body; and a control device for lifting / lowering the seedling planting part via the lifting link mechanism. The control device lifts / lowers the seedling planting part according to changes in the pitching angle.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] 2. Description of the Related Art A work vehicle is known that uses a float to level the surface of a field, detects unevenness in the field surface, and raises and lowers a seedling planting unit to keep the seedlings planted at a constant depth (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-106566 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, the float rotates due to the unevenness of the field surface. In the conventional technology, the planting depth of the seedlings is controlled based on the float angle, which is the rotation angle of the float. However, when the traveling vehicle body is disturbed by the unevenness of the field surface or when planting while climbing a sloping ridge, the seedling planting part moves up and down relative to the field surface, so the seedling planting depth cannot be constant. If a sensor that directly senses the field surface is provided in the seedling planting part, additional costs and design changes are required. Therefore, there has been a demand for a work vehicle that can plant seedlings along the field surface according to the field conditions without using a sensor that directly senses the field surface.

[0005] The present invention has been made in consideration of the above, and aims to provide a work vehicle that can plant crops along the surface of a field in accordance with the field conditions, without using a sensor that directly senses the surface of the field. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a work vehicle (1) according to one aspect of the embodiment includes a traveling body (2) that travels in a field, a seedling planting unit (4) that plants seedlings taken from a seedling mat loaded at the rear of the traveling body (2) in the field, a lifting link mechanism (3) that supports the seedling planting unit (4) so ​​that it can be raised and lowered, a pitching angle sensor (150) that detects the pitching angle of the traveling body (2), and a control device (100) that raises and lowers the seedling planting unit via the lifting link mechanism (3), and the control device (100) raises and lowers the seedling planting unit (4) in accordance with changes in the pitching angle. Effect of the Invention

[0007] According to one aspect of the embodiment, the work vehicle can plant crops so as to follow the surface of the field in accordance with the field conditions, without using a sensor that directly senses the surface of the field. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view showing a work vehicle. [Diagram 2] FIG. 2 is a plan view showing the work vehicle. [Diagram 3] FIG. 3 is an explanatory diagram of the HST. [Figure 4] FIG. 4 is a diagram illustrating the lever guide portion. [Diagram 5] FIG. 5 is a block diagram showing a control system centered on the control device of the seedling transplanter. [Figure 6] FIG. 6 is a diagram illustrating the elevation and lowering of the seedling planting section in response to changes in the pitching angle. [Figure 7] FIG. 7 is a diagram illustrating the elevation and lowering of the seedling planting section in response to changes in the pitching angle. [Figure 8] FIG. 8 is a diagram illustrating the field depth. [Figure 9] FIG. 9 is a diagram for explaining the target planting depth when the float sags. [Figure 10] FIG. 10 is a diagram for explaining the target value of the planting depth when the float is lifted. [Figure 11] FIG. 11 is a diagram illustrating the process of changing the target value of the planting depth in response to an increase in the bending angle. [Figure 12] FIG. 12 is a diagram for explaining the distance in the front-rear direction from the front wheels of the traveling vehicle body to the seedling planting section. [Figure 13] FIG. 13 is a diagram illustrating a motorized implant rod. [Figure 14] FIG. 14 is a diagram for explaining the arrangement of the motor control MDU and the main ECU. [Figure 15] FIG. 15 is a diagram for explaining the arrangement of the motor control MDU and the main ECU. [Figure 16] FIG. 16 is a diagram illustrating the arrangement of the light emitting devices. [Figure 17] FIG. 17 is a diagram for explaining the light emitting position of the light emitting device. [Figure 18] FIG. 18 is a diagram for explaining the light emitting position of the light emitting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, an overview of a work vehicle 1 according to an 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 plan view showing the work vehicle 1.

[0010] In the following description, the forward / rearward direction is the direction of travel of the work vehicle 1 when traveling straight, with the forward side in the direction of travel being defined as "front" and the rear side being defined as "rear." The forward direction of the work vehicle 1 is the direction from the driver's seat 41 toward the handle 35 (steering device) when traveling straight (see Figures 1 and 2).

[0011] The left-right direction is a direction that is horizontally perpendicular to the front-rear direction and defines left and right facing the "front." In other words, when a pilot (also called an operator) is seated in the pilot's seat 41 and facing forward, the left hand side is the "left" and the right hand side is the "right."

[0012] The up-down direction is the vertical direction. The front-rear direction, the left-right direction, and the up-down direction are perpendicular to each other. Each direction is defined for the convenience of explanation, and the present invention is not limited to these directions.

[0013] In the embodiment, the work vehicle 1 will be described as a riding seedling transplanter 1 that is equipped with a seedling planting unit 4 as a working device and receives seedlings in a field. As shown in Figures 1 and 2, the seedling transplanter 1 is equipped with the seedling planting unit 4 that can be raised and lowered via a lifting link mechanism 3 on the rear side of the traveling body 2 to plant seedlings in the field.

[0014] A main body of the fertilizer applicator 5 is disposed on the upper rear side of the traveling body 2. When the work vehicle 1 is not a seedling transplanter 1, it may be equipped with a sowing device for supplying seeds as a work device.

[0015] The traveling body 2 is a four-wheel drive vehicle equipped with left and right front wheels 10 and rear wheels 11, which are driving wheels. On the front side of the main frame 15 constituting the body framework of the traveling body 2, there are provided a transmission case 13 that transmits driving force to the seedling planting section 4 and the like, and a hydraulic continuously variable transmission 14 that outputs the driving force supplied from the engine 30, i.e., 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 HST (Hydro Static Transmission). In the following, a case where the continuously variable transmission is the HST 14 will be described.

[0017] The HST 14 will now be described with reference to Fig. 3. Fig. 3 is an explanatory diagram of the HST 14.

[0018] 3, the HST 14 uses power from the engine 30 to drive a hydraulic pump 141 to generate hydraulic pressure, which is then converted into mechanical force (rotational force) by a hydraulic motor 142 and output. At this time, by operating the main transmission operation lever 36 described below, the rotation angle (hereinafter referred to as the "trunnion opening") of a trunnion shaft 147 of the HST 14 is changed via a trunnion shaft actuator such as an HST motor 146, thereby changing the tilt angle of a swash plate 148, and the output of the HST 14 can be changed steplessly.

[0019] That is, pressure oil according to the tilt angle of the swash plate 148 is supplied from the hydraulic closed circuit 143 to the hydraulic motor 142, and the hydraulic motor 142 drives the output shaft 145 to change the rotation speed of the front wheels 10 and the rear wheels 11. In this way, the HST 14 converts the power generated by the engine 30 into a force for moving the traveling body 2, and by changing the output and the output direction, it is possible to control the forward / reverse movement and traveling speed (vehicle speed) of the traveling body 2. In addition, in Fig. 3, reference numeral 80 denotes an input shaft of the HST 14, which is connected to the output shaft 30a of the engine 30 via the main clutch 30b. It is to be noted that the trunnion shaft actuator may be of a hydraulic type.

[0020] 1 and 2, an auxiliary transmission mechanism 16 is provided in the transmission case 13 for switching the driving mode of the traveling vehicle body 2 between high-speed mode for road driving and low-speed mode for planting seedlings. That is, the auxiliary transmission mechanism 16 switches between a high-speed mode for road speed and a low-speed mode for planting speed. A front wheel final case 10a is provided on the left and right sides of the transmission case 13, and the front wheels 10 are attached to left and right front axles 10b that protrude outward from front wheel support parts that can change the steering direction of the left and right front wheel final cases 10a.

[0021] In addition, rear wheel gear cases 11a are attached to both the left and right sides of a rear frame 22 (see Figure 2) that is provided laterally on the rear side of the main frame 15, and rear wheels 11 are respectively attached to left and right rear axles 11b that protrude outward from the rear wheel gear case 11a.

[0022] Left and right link support frames 23 that support the lifting link mechanism 3 protrude upward from the upper part of the rear frame 22. A pair of left and right lower link arms 24 are provided below and between the left and right link support frames 23. A hydraulically operated lifting cylinder 25 is provided between the left and right lower link arms 24.

[0023] An upper link arm 26 is provided above the lifting cylinder 25, forming a parallel link mechanism, the lifting link mechanism 3. The left and right lower link arms 24, the lifting cylinder 25, and the other end of the upper link arm 26, each of which has one end connected to the traveling body 2, are attached to the front of the seedling planting section 4.

[0024] In addition, an engine 30 is mounted on the main frame 15. 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 changed in speed by the sub-transmission mechanism 16 in the transmission case 13, and then separated into traveling power and externally extracted power.

[0025] The rotational power of the engine 30 is transmitted to a hydraulic pump. The hydraulic pressure generated by the hydraulic pump is supplied to the HST 14, a power steering mechanism 88 (see FIG. 5) of the handle 35, the lift cylinder 25, etc.

[0026] The external extraction power extracted from the rotational power transmitted to the transmission case 13 is transmitted to a planting clutch case 27 provided at the rear of the running body 2, and transmitted from the planting clutch case 27 to the seedling planting section 4 via a planting transmission shaft 67.

[0027] Meanwhile, left and right drive shafts 42 are provided at the rear of the transmission case 13. Rotational power from the engine 30 is transmitted via the transmission case 13 and the drive shafts 42 to the left and right rear wheel gear cases 11a.

[0028] A side clutch 44 (see FIG. 5) that switches on and off the power transmission to the left and right drive shafts 42 is disposed upstream in the transmission direction from the left and right drive shafts 42. As shown in FIG. 1, a side clutch pedal 43a that switches on and off the left and right side clutches 44 is provided at the lower front side of the cockpit 41 and on one of the left and right sides.

[0029] Of the left and right side clutch pedals 43a, 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 make a turn, the drive rotation of the rear wheel 11 on the inside of the turn can be completely cut off.

[0030] A bonnet 39 with an operation panel 38 arranged on top for operating each part is provided on the upper front side of the traveling body 2. The operation panel 38 is provided with a monitor 86 (see FIG. 5) and the like.

[0031] The bonnet 39 is also provided with a handlebar 35 for steering the traveling body 2, a main speed change operation lever 36 for operating the HST 14 and the seedling planting section 4, an auxiliary speed change operation lever 37 for operating the auxiliary speed change mechanism 16, and the like.

[0032] The main speed change operation lever 36 is an operating tool that can adjust the speed of the traveling vehicle body 2 by adjusting the opening degree of the trunnion shaft 147 of the HST 14. The main speed change operation lever 36 is operated, for example, by a driver. The main speed change operation lever 36 accepts a speed change operation by the driver.

[0033] The main transmission operation lever 36 is provided so as to be movable along a lever guide portion 815, for example, as shown in Fig. 4. Fig. 4 is a diagram for explaining the lever guide portion 815. As shown in Fig. 4, the lever guide portion 815 is largely divided into a forward travel area 811 on the front side of the vehicle body, a reverse travel area 813 on the rear side of the vehicle body, and a neutral area 812 located so as to be sandwiched between them. Note that the lever guide portion 815 in Fig. 4 is merely an example, and is not limited thereto.

[0034] When the main speed change lever 36 is positioned in the forward travel area 811, the seedling transplanter 1 moves forward, and the closer it is to the front, the faster it moves. When the main speed change lever 36 is positioned in the reverse travel area 813, the seedling transplanter 1 moves backward, and the closer it is to the rear, the faster it moves.

[0035] That is, main transmission control lever 36 is provided so that its position can be changed across a forward travel region 811 and a reverse travel region 813, sandwiching neutral region 812, and the output of HST 14 can be adjusted according to the operation position. That is, the inclination angle of swash plate 148 of HST 14 changes according to the amount of operation of main transmission control lever 36 within lever guide portion 815, and the output from HST 14, i.e., the travel speed, is changed steplessly.

[0036] The rotation speed of the engine 30 is set according to the amount of operation of the main transmission control lever 36. For example, when the main transmission control lever 36 is located in the forward travel area 811, the rotation speed of the engine 30 increases as the main transmission control lever 36 approaches the frontmost position.

[0037] On the other hand, when the main speed change lever 36 is placed in the neutral region 812, the output from the HST 14 is stopped and the seedling transplanter 1 stops. Furthermore, in the seedling transplanter 1, the front wheels 10 and the rear wheels 11 are forcibly braked at this time.

[0038] When the driver stops operating the main transmission operation lever 36, the main transmission operation lever 36 is held in the position where the driver stopped operating the main transmission operation lever 36.

[0039] Also, as shown in Fig. 5, a setting switch 49 is provided on the bonnet 39, which can change and set the upper limit of the trunnion opening of the HST 14. The setting switch 49 is, for example, a switch that is provided so as to be rotatable in the vertical direction. The setting switch 49 is a switch for setting the upper limit of the trunnion opening when the traveling vehicle body 2 moves forward and backward. The setting switch 49 accepts the operator's operation to set the upper limit opening.

[0040] When the setting switch 49 is in the upper first position, for example, the vehicle speed mode is set to the first vehicle speed mode. In the first vehicle speed mode, the upper limit of the trunnion opening is set to the first upper limit. The first upper limit is the normal upper limit and is set according to the position of the main transmission operation lever 36.

[0041] When the setting switch 49 is, for example, in the lower second position, the vehicle speed mode is set to the second vehicle speed mode. In the second vehicle speed mode, the upper limit of the trunnion opening is set to a second upper limit. The second upper limit is smaller than the first upper limit. In other words, the second vehicle speed mode is a mode in which the speed of the traveling vehicle body 2 is slower than in the first vehicle speed mode.

[0042] The first upper limit opening degree and the second upper limit opening degree are set to different opening degrees when the traveling vehicle body 2 is moving forward and when it is moving backward. For example, in the second vehicle speed mode, the second upper limit opening degree when moving backward is smaller than the second upper limit opening degree when moving forward.

[0043] For example, the vehicle speed in the second vehicle speed mode is about 20% of the vehicle speed in the first vehicle speed mode, and for example, the vehicle speed in the second vehicle speed mode when reversing is about 30% of the vehicle speed in the first vehicle speed mode when reversing.

[0044] The trunnion opening here is the opening relative to a state in which the swash plate 148 (see FIG. 3) is not tilted. The trunnion openings during forward and reverse travel are, for example, amounts of change relative to a state in which the swash plate 148 is not tilted, and will be described as positive values. The setting switch 49 may be provided separately for forward travel and reverse travel.

[0045] 1 and 2, an openable and closable front cover 40 is provided in front of the bonnet 39. A fuel tank, a battery, and an interlocking mechanism for rotating the left and right front wheels 10 and the lower sides of the left and right front wheel final cases 10a in response to steering of the handlebars 35 are provided inside the front cover 40. The front wheels 10 are steered wheels that are steered in response to steering of the handlebars 35, for example.

[0046] An engine cover 30c that covers the top and sides of the engine 30 is provided behind the bonnet 39 and above the engine 30, and a pilot's seat 41 where the pilot is seated is provided above the engine cover 30c.

[0047] The fertilizer applicator 5 is provided behind the driver's seat 41 and at the rear end side of the main frame 15. The driving force of the fertilizer applicator 5 is transmitted by a fertilizer transmission mechanism provided to face the fertilizer applicator 5 from one of the left and right rear wheel gear cases 11a.

[0048] A substantially horizontal floor step 33 is formed on both the left and right sides of the lower portion of the engine cover 30c and the bonnet 39. As shown in Fig. 2, the floor step 33 is partially lattice-shaped, so that even if mud on the shoes of an operator walking on the floor step 33 falls, the fallen mud falls into the field.

[0049] An accelerator pedal 110 that can be depressed by the driver is provided on the floor step 33. The accelerator pedal 110 is biased toward a predetermined initial position by a biasing means such as a spring. Specifically, when the driver does not depress the accelerator pedal 110, the accelerator pedal 110 is biased by the biasing means to the initial position. When the driver depresses the accelerator pedal 110, the accelerator pedal 110 rotates from the initial position in response to the driver's depressing force. When the driver stops depressing the accelerator pedal 110, the accelerator pedal 110 returns to the initial position by the biasing force of the biasing means.

[0050] 2, a rear step 330 is connected to the rear of the floor step 33. It is preferable that the surface of the rear step 330 is subjected to an anti-slip treatment, for example, a pattern of multiple projections, so that the feet do not easily slip during work.

[0051] In addition, at the front of the traveling body 2, on both the left and right sides, spare seedling frames 50 are provided, in which multiple spare seedling carrying platforms 52 are arranged at intervals in the vertical direction on seedling frame supports 51, so that work materials such as seedlings and fertilizer bags to be replenished in the seedling planting section 4 can be placed on them.

[0052] 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 together with a sliding mechanism for sliding it left and right. Seedling partition fences 54 that are long in the vertical direction are arranged at predetermined intervals in the horizontal direction on the seedling tank 53. A seedling planting device 55 is arranged below the seedling tank 53 to pick up the loaded seedlings and plant them in the field.

[0053] The seedling planting device 55 plants the same number of seedling rows as those separated by the seedling partition fence 54, i.e., eight rows at a time. Four planting transmission cases 56 are arranged at intervals below the seedling tank 53, and planting rotaries 57 are attached to both the left and right sides of the planting transmission cases 56, which rotate to pick up seedlings using planting rods 58 and plant them in the field.

[0054] In the fertilizer applicator 5, the fertilizer hopper 70 in which the fertilizer is stored is divided into the same number of sections as the number of working rows in the seedling planting section 4 (8 rows in the example shown in FIG. 2). Since the fertilizer hopper 70 with 8 rows is long in the left-right direction and therefore the convenience of adding fertilizer and attaching and detaching it is reduced, the fertilizer hopper 70 may have a so-called side fertilizer application structure in which sections divided into 4 rows are arranged on each side.

[0055] A payout device 71 that supplies a set amount of fertilizer at each row is provided below the fertilizer hopper 70. A ventilation duct 72 through which conveying air that moves the fertilizer passes is provided in the left-right direction below the payout device 71. A fertilizer hose 73 that guides fertilizer to the vicinity of the seedling planting position in the seedling planting section 4 is provided below the payout device 71. In addition, a blower 74 that is operated by an electric blower motor 76 to generate conveying air is provided at one end of the ventilation duct 72.

[0056] The amount of fertilizer supplied to the field (fertilizer application amount) can be adjusted by controlling the delivery device 71. For example, the amount of fertilizer supplied to the field can be adjusted by controlling the rotation speed of a delivery section provided in the delivery device 71 and having a recess into which the fertilizer flows from the fertilizer application hopper 70.

[0057] As shown in Figures 1 and 2, below the seedling planting section 4, a center float 62C that slides on the surface of the field and two side floats 62L, 62R are provided so as to be rotatable about their axes. The center float 62C and the left and right side floats 62L, 62R are sometimes collectively referred to as floats 62. The float 62 is supported at its rear by a support member and can rotate around the axis of its connection with the support member in response to unevenness in the field surface, leveling the field surface. A link mechanism having a float angle sensor 94, which will be described later, is provided at the tip of the center float 62C.

[0058] The float 62 adjusts the planting depth of the seedlings planted in the seedling planting unit 4 by means of a planting depth adjustment mechanism 77. The planting depth adjustment mechanism 77 is capable of adjusting the planting depth of the seedlings by adjusting the vertical position of the seedling planting unit 4 relative to the field, and is capable of adjusting the vertical position of the seedling planting unit 4 relative to the field by adjusting the relative vertical positions of the float 62 and the seedling planting unit 4. The planting depth adjustment mechanism 77 is configured so that the planting depth becomes deeper by raising the float 62 and the planting depth becomes shallower by lowering the float 62.

[0059] In addition, below the seedling planting section 4, and ahead of the float 62, a ground leveling rotor 63 for leveling the unevenness of the field surface is provided. A driving force is transmitted to the ground leveling rotor 63 from the rear wheel gear case 11a on the other left or right side via a rotor transmission shaft 63a.

[0060] 1, line drawing markers 65 are provided on both the left and right sides of the seedling planting section 4, one of which comes into contact with the surface of the field to form a groove that serves as a guide for traveling in the next work row (next process). When one of the left and right line drawing markers 65 comes into contact with the ground, the other moves upward, and when the seedling planting section 4 is raised during a turn, both the left and right sides move upward, and when the seedling planting section 4 descends after a turn, one of the left and right sides moves upward and the other side comes into contact with the ground.

[0061] 1 and 2, a center mascot 66 that is long in the vertical direction is provided in the left-right center of the traveling body 2 and in front of the bonnet 39. By aligning the center mascot 66 with the grooves formed in the field by the left and right line markers 65, it becomes possible to travel in accordance with the work position of the previous work row, improving work accuracy and preventing non-working.

[0062] Depending on the soil quality of the field, the guide lines formed by the left and right line-drawing markers 65 may quickly become buried, and the indication for going straight may disappear. In such a case, it is better to use the left and right side markers 19 provided forward of the left and right line-drawing markers 65. That is, by moving the left and right side markers 19 outward and positioning the side markers 19 above the planted seedlings, it becomes possible to perform planting work in accordance with the planting of the seedlings in the previous work row.

[0063] As shown in FIG. 1, the seedling transplanter 1 includes a position detection device 150. The position detection device 150 detects the current position and orientation of the seedling transplanter 1. That is, the position detection device 150 detects information about the position of the traveling body 2 and the orientation of the traveling body 2. The position detection device 150 includes, for example, an orientation sensor, a positioning means such as a Global Positioning System (GPS) or a Global Navigation Satellite System (GNSS). The position detection device 150 may be composed of multiple devices. The position detection device 150 may include a camera or an ultrasonic sensor, and may obtain a turning position in a field and detect a distance to the turning position.

[0064] The seedling transplanter 1 also includes a pitching angle sensor. The pitching angle sensor detects the horizontal position of the traveling body 2 in the pitching direction and the pitching angle of the traveling body 2. The pitching angle sensor is, for example, a GNSS equipped with a function of detecting the horizontal position of the traveling body 2 in the pitching direction and the pitching angle of the traveling body 2, and also serves as the position detection device 150. The pitching angle sensor may be an inclination sensor 92 described later.

[0065] For example, the position detection device 150 receives positioning information from a positioning means, creates current position information and direction information of the traveling vehicle body 2 based on the received positioning information, and detects the current position and direction. The position detection device 150 is attached to the mounting stay 59, for example, and disposed above the traveling vehicle body 2.

[0066] A straight-line control program and a turning control program, which are created based on position information from the position detection device 150, are stored in different locations. The straight-line control program is stored, for example, in a straight-line control ECU (Electronic Control Unit) 100a in the position detection device 150, and the turning control program is stored, for example, in a turning control ECU 100b housed in the bonnet 39. The straight-line control ECU 100a and the turning control ECU 100b are included in a control device 100 (see FIG. 5), which will be described later. The straight-line control ECU 100a and the turning control ECU 100b may be stored in the same ECU.

[0067] Next, the control system of the seedling transplanter 1 will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the control system centered on the control device 100 of the seedling transplanter 1. 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.

[0068] The controller 100 is provided with a processing section having a CPU (Central Processing Unit) and the like, a storage section such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input / output section, which are connected to each other and can exchange signals with each other. The storage section stores computer programs and the like for controlling the seedling transplanter 1. The controller 100 performs each function by reading out the computer programs and the like stored in the storage section.

[0069] The controller 100 is connected to actuators such as a throttle motor 80, hydraulic control valves 81, 82, a planting clutch actuation solenoid 83, a side clutch actuation solenoid 84, an HST motor 146, a line drawing marker lifting motor 87, a steering motor 95, and a differential lock switching motor 96.

[0070] The throttle motor 80 increases or decreases the rotation speed of the output shaft 30a of the engine 30 by operating a throttle that adjusts the amount of intake air of the engine 30. The hydraulic control valve 81 controls the extension and contraction operation 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 that are the steering wheels of the traveling body 2. The planting clutch operating solenoid 83 operates the planting clutch 27a. When the planting clutch 27a is in the "ON" state, the planting rotary 57 rotates and the planting rod 58 plants the seedlings. When the planting clutch 27a is in the "OFF" state, the planting rotary 57 does not rotate and the planting rod 58 does not plant the seedlings.

[0071] The side clutch actuation solenoid 84 actuates the side clutch 44 which switches the state of power transmission to the rear wheels 11 (see FIG. 1). The side clutch 44 is provided on each of the left and right rear wheels 11, and two side clutch actuation solenoids 84 are provided corresponding to each side clutch 44.

[0072] The HST motor 146 changes the inclination angle of a swash plate 148 of the HST 14 by changing the trunnion opening of the HST 14. The steering motor 95 is a motor that drives the handle 35, which is a steering device that adjusts the steering amount (steering angle) of the front wheels 10 (see FIG. 1) when automatic turning control is performed. The steering motor 95 rotates the handle 35. The line drawing marker lifting motor 87 lifts and lowers the line drawing marker 65.

[0073] The differential lock switching motor 96 is a motor that switches between operation and deactivation of a differential lock mechanism 97 (hereinafter referred to as the differential lock mechanism) that rotates the left and right running wheels, specifically the left and right front wheels 10, at the same rotational speed. When the differential lock mechanism 97 is engaged, the left and right running wheels rotate at the same rotational speed.

[0074] The controller 100 is connected to detection devices such as a rotation speed sensor 90, a steering amount sensor 91, an inclination sensor 92, a link angle sensor 93, and a float angle sensor 94. Two rotation speed sensors 90 are provided corresponding to the left and right rear wheels 11, and detect the rotation speeds of the left and right rear wheels 11, respectively. The rotation speed sensor 90 is capable of calculating the travel distance from the rotation speed of the rear wheels 11, and also serves as a travel distance sensor. The rotation speed sensor 90 may detect the rotation speeds of the left and right front wheels 10.

[0075] The steering amount sensor 91 detects the operation position of the steering wheel 35, which is a steering device, i.e., the steering amount (steering angle) of the front wheels 10. The steering amount sensor 91 is provided, for example, on a shaft connected to a pitman arm. The steering amount is detected in both the left and right directions, with a value when the steering wheel 35 is in a preset straight-ahead position being used as a reference value.

[0076] The inclination sensor 92 detects the inclination angle of the traveling vehicle body 2. The inclination sensor 92 detects the inclination angle in the front-rear direction of the traveling vehicle body 2. The inclination sensor 92 is, for example, a G sensor.

[0077] The link angle sensor 93 detects the link angle, which is the tilt angle of the lifting / lowering link mechanism 3. For example, the link angle sensor 93 is provided near the connection between the upper link arm 26 and the link support frame 23 in the lifting / lowering link mechanism 3, and is able to detect the link angle by detecting the relative angle of the upper link arm 26 with respect to the link support frame 23.

[0078] The float angle sensor 94 detects the float angle, which is the rotation angle of the float 62. For example, the float angle sensor 94 is provided on the link mechanism at the front end of the center float 62c, and is capable of detecting the float angle by detecting the inclination angle of the center float 62c.

[0079] In addition, signals are input to the controller 100 as operation signals from the main speed change lever 36, the sub-speed change lever 37, the setting switch 49, the autonomous driving changeover switch 46, the planting section lifting / lowering switch 47, the automatic straight-line changeover switch 45, the automatic turning changeover switch 48, and the accelerator pedal 110.

[0080] The autonomous driving changeover switch 46 is a switch for switching whether or not to execute autonomous driving. Specifically, the autonomous driving changeover switch 46 is a switch for switching the driving mode between a manual driving mode and an autonomous driving mode (automatic driving mode). The manual driving mode is a mode in which the vehicle travels by manual operation of an operator. The autonomous driving mode is a mode in which the vehicle travels automatically without manual operation of an operator.

[0081] For example, when the autonomous driving changeover switch 46 is "ON", the driving mode is set to the autonomous driving mode. When the autonomous driving changeover switch 46 is "OFF", the driving mode is set to the manual driving mode. When the autonomous driving changeover switch 46 is turned "ON", the automatic straight-line driving changeover switch 45 and the automatic turning changeover switch 48 are turned "ON". In other words, when the driving mode is the autonomous driving mode, the automatic straight-line driving changeover switch 45 and the automatic turning changeover switch 48 can be changed to "OFF" by the driver's operation even if they have been turned "ON" once.

[0082] The planting section lifting switch 47 is a switch for switching whether to lift or lower the seedling planting section 4. The planting section lifting switch 47 is changed to the "up" and "down" positions.

[0083] When the planting section lift switch 47 is in the "up" position, the seedling planting section 4 rises to a predetermined lift position and the seedling planting device 55 stops, entering a non-ground operation state. When the seedling planting section 4 enters the non-ground operation state, the planting clutch 27a enters the "off" state.

[0084] When the planting unit lift switch 47 is in the "down" position, the seedling planting unit 4 descends to a predetermined lowered position and enters an operating state in which the seedling planting device 55 is activated. In other words, the planting unit lift switch 47 is a switch that detects the operating state of the seedling planting unit 4. Note that a separate switch that detects the operating state of the seedling planting unit 4 may be provided. When the seedling planting unit 4 enters an operating state, the planting clutch 27a enters the "on" state.

[0085] The automatic straight-line driving changeover switch 45 is a switch that switches whether or not automatic straight-line driving is enabled. When the automatic straight-line driving changeover switch 45 is set to "ON," a driving assist function, which will be described later, is enabled, and automatic straight-line driving can be executed. When the automatic straight-line driving changeover switch 45 is set to "OFF," the driving assist function is disabled, and automatic straight-line driving cannot be executed.

[0086] The automatic turning changeover switch 48 is a switch that switches whether or not automatic turning is enabled. When the automatic turning changeover switch 48 is set to "ON", a turning assist function, which will be described later, is enabled, and automatic turning can be performed. When the automatic turning changeover switch 48 is set to "OFF", the turning assist function is disabled, and automatic turning cannot be performed. When the automatic turning changeover switch 48 is set to "OFF", automatic turning is not performed even if the conditions for performing automatic turning are met.

[0087] The controller 100 switches the driving mode between a manual driving mode and an autonomous driving mode in response to the operation of the autonomous driving changeover switch 46, the automatic straight-line driving changeover switch 45, and the automatic turning changeover switch 48.

[0088] Further, the controller 100 receives current position information of the traveling vehicle body 2 from the position detection device 150. The controller 100 executes an autonomous traveling mode in which the traveling vehicle body 2 performs work while traveling automatically.

[0089] The controller 100 has an autonomous driving mode (automatic driving mode) in which the steering motor 95 is controlled to operate the handlebars 35 while feeding back the steering amount of the front wheels 10 (see FIG. 1). The autonomous driving mode includes an automatic straight-line mode and an automatic turning mode.

[0090] The automatic straight-line mode is a mode in which the steering motor 95 is controlled so that the traveling body 2 travels straight along a preset straight-line route. In the automatic straight-line mode, the traveling body 2 travels straight without the operation of the driver while the seedling planting unit 4 plants seedlings in the field. In other words, the traveling assist function for transplanting seedlings in the field while automatically moving the traveling body 2 straight is enabled, and the traveling assist function is executed.

[0091] In the automatic turning mode, when the traveling body 2 reaches a predetermined planting end position, the seedling planting unit 4 stops planting the seedlings, and the steering motor 95 is controlled to turn the traveling body 2 along a preset turning path. The predetermined planting end position is set, for example, based on the travel distance of the process where the work was performed, position information related to the process where the work was performed, etc.

[0092] In the automatic turning mode, for example, the seedling planting unit 4 is raised and put into a non-working state, and the traveling body 2 turns automatically without the operation of the driver. In other words, the turning assist function for turning the traveling body 2 is enabled without the seedling planting unit 4 planting seedlings, and the turning assist function is executed.

[0093] Moreover, various information is input to the controller 100 from a remote control device 170 (hereinafter referred to as the "remote control"). For example, various information is input to the controller 100 from the remote control 170 via a receiver 180 (see FIG. 1). The receiver 180 is attached, for example, to a mounting stay 59 (see FIG. 1) and disposed above the front side of the traveling vehicle body 2. Note that a plurality of receivers 180 may be provided. The mounting stay 59 is attached to the traveling vehicle body 2.

[0094] The remote control 170 can remotely control the seedling transplanter 1. The remote control 170 is a terminal device such as a smartphone. The remote control 170 transmits a control signal according to an operation by an operator. The remote control 170 is communicably connected to the controller 100 by short-range wireless communication such as Wi-fi (registered trademark) or BLE (Bluetooth (registered trademark) Low Energy), but is not limited thereto, and may be communicatively connected via a communication network or the like in addition to or instead of the short-range wireless communication.

[0095] A plurality of remote controls 170 may be provided. That is, the controller 100 may be capable of acquiring position information of each remote control 170 from the plurality of remote controls 170. The remote control 170 may be attachable to the seedling transplanter 1.

[0096] The controller 100 controls the speed of the engine 30 and the trunnion opening of the HST 14, thereby controlling the vehicle speed of the traveling vehicle body 2.

[0097] The controller 100 sets the vehicle speed mode to the first vehicle speed mode or the second vehicle speed mode in response to the operation of the setting switch 49. That is, the controller 100 sets the trunnion opening of the HST 14 to the first upper limit opening or the second upper limit opening in response to the operation state of the setting switch 49.

[0098] When the vehicle speed mode is the first vehicle speed mode, the controller 100 controls the trunnion opening of the HST 14 in accordance with the position (operation amount) of the main shift operation lever 36 so that the vehicle speed of the traveling vehicle body 2 becomes a vehicle speed according to the position of the main shift operation lever 36. The controller 100 controls the trunnion opening of the HST 14 while setting the trunnion opening of the HST 14 to a first upper limit opening.

[0099] When the vehicle speed mode is the second vehicle speed mode, the controller 100 restricts the trunnion opening of the HST 14 to the second upper limit opening. This limits the vehicle speed of the traveling vehicle body 2 to a lower vehicle speed compared to when the vehicle speed mode is the first vehicle speed mode. The rotation speed of the engine 30 is set according to the position of the main shift operation lever 36.

[0100] Next, the automatic raising and lowering process of the seedling planting section 4 according to the pitching angle will be described with reference to Figures 6 and 7. Figures 6 and 7 are diagrams for explaining the raising and lowering of the seedling planting section 4 according to the change in pitching angle.

[0101] As shown in FIG. 6 and FIG. 7, the controller 100 raises and lowers the seedling planting section 4 according to the change in the pitching angle (the inclination angle in the front-rear direction of the traveling body 2) of the traveling body 2. For example, when the traveling body 2 travels uphill such as a ridge, the pitching angle changes so that the front side of the traveling body 2 is higher than the rear side, and the seedling planting section 4 on the rear side of the traveling body 2 approaches the surface of the field. The controller 100 raises the seedling planting section 4 so that the seedling planting section 4 (planting position P) is at a constant height relative to the surface of the field. In this way, even when the work vehicle 1 is planting seedlings while climbing a slope-shaped ridge or when the traveling body 2 is unstable due to the unevenness of the field, it can plant seedlings along the surface of the field in accordance with the field conditions without using a sensor that directly senses the surface of the field. In addition, the work vehicle 1 can plant seedlings up to the edge of the ridge without the trouble of planting them by hand.

[0102] Next, the process of changing the target value of the planting depth according to the field depth and the float angle will be described with reference to Figs. 8 to 10. Fig. 8 is a diagram explaining the field depth L1. Fig. 9 is a diagram explaining the target value L2 of the planting depth when the float 62 sags. Fig. 10 is a diagram explaining the target value L2 of the planting depth when the float 62 is lifted.

[0103] The controller 100 calculates the field depth L1 relative to the wheel contact surface of the traveling body 2 based on the link angle θ1 (see FIG. 6) detected by the link angle sensor 93. The field depth L1 is the distance from the contact surface of the hard bed layer on which the wheels of the traveling body 2 contact the ground to the surface of the plowed soil layer. The controller 100 sets the target planting depth L2 according to the field depth L1. For example, when the field depth L1 is deep, the controller 100 sets the target planting depth L2 small (shallow planting depth), and when the field depth L1 is shallow, the controller 100 sets the target planting depth L2 large (deep planting depth). In this way, the work vehicle 1 can plant at an appropriate planting depth by changing the target planting depth L2 according to the field depth L1.

[0104] As shown in FIG. 9 and FIG. 10, the controller 100 changes the target value L2 of the planting depth according to the float angle θ2. Specifically, the controller 100 sets a reference value of the float angle θ2, and when the float 62 sags below the reference value, the planting position P of the seedling planting section 4 becomes lower based on the surface of the field, so the controller 100 reduces the target value L2 of the planting depth (lowers the float 62). Also, when the float 62 is raised above the reference value by a certain amount, the controller 100 increases the target value L2 of the planting depth (raises the float 62) because the planting position P of the seedling planting section 4 becomes higher based on the surface of the field. For example, the reference value of the float angle θ2 is set to the float angle θ2 when the float 62 is horizontal. In this way, the work vehicle 1 can raise and lower the seedling planting section 4 according to the pitching angle and correct the planting depth according to the float angle θ2, thereby allowing planting to be performed at a more appropriate planting depth.

[0105] The controller 100 uses PID control to control the target value L2 of the planting depth according to the float angle θ2. By using PID control, the controller 100 can suppress the control amount when the float angle θ2 suddenly changes and prevent steady-state deviation from remaining.

[0106] Furthermore, the traveling vehicle body 2 is provided with a sensitivity adjustment dial 34 (see FIG. 5) on, for example, the bonnet 39. The sensitivity adjustment dial 34 is configured so that the dial can be rotated to a soft side when the field is soft and to a hard side when the field is hard. When the sensitivity adjustment dial 34 is rotated to the soft side, the controller 100 changes the setting of the reference value of the float angle θ2 to the drooping side, and when the sensitivity adjustment dial 34 is rotated to the hard side, the controller 100 changes the setting of the reference value of the float angle θ2 to the lifting side. In addition, the controller 100 changes each gain of the PID control by rotating the sensitivity adjustment dial 34.

[0107] For example, the controller 100 decreases the P gain, decreases the I gain, and increases the D gain as the sensitivity adjustment dial 34 is rotated toward the hard side. Also, the controller 100 increases the P gain, increases the I gain, and decreases the D gain as the sensitivity adjustment dial 34 is rotated toward the soft side. That is, the controller 100 suppresses (makes insensitive) the elevation of the seedling planting unit 4 in response to changes in the float angle θ2 by adjusting the gain. The controller 100 can make more accurate adjustments according to the hardness or softness of the field by changing the gain of the PID control in addition to setting the reference value of the float angle θ2. The controller 100 increases or decreases the target value L2 of the planting depth when the control value of the PID control exceeds a certain threshold value.

[0108] Next, the automatic raising and lowering process of the seedling planting section 4 based on the bending angle and the process of changing the target value L2 of the planting depth will be described with reference to Fig. 11. Fig. 11 is a diagram for explaining the process of changing the target value L2 of the planting depth according to an increase in the bending angle. The controller 100 controls the float 62 to maintain the horizontal state by lowering the seedling planting section 4 when the float 62 hangs down from the horizontal state based on the float angle θ2, and by raising the seedling planting section 4 when the float 62 is raised from the horizontal state.

[0109] The controller 100 calculates the bending angle, which is the angle between the wheel contact surface of the traveling body 2 and the float contact surface, based on the transition of the pitching angle and the travel distance of the traveling body 2. For example, when the traveling body 2 travels uphill and the rear wheels 11 approach the uphill slope, the bending angle becomes maximum and the seedling planting unit 4 sinks into the field. The controller 100 adjusts the link angle θ1 according to the bending angle and raises the seedling planting unit 4.

[0110] Furthermore, the controller 100 uses the turning angle when the traveling body 2 travels on a horizontal field as a reference, and when the angle is a positive angle when the wheel contact surface of the traveling body 2 is uphill and a negative angle when the wheel contact surface of the traveling body 2 is downhill, increases the target planting depth L2 as the turning angle increases. As the traveling body 2 of the work vehicle 1 travels uphill, the float 62 tilts and the rear of the float 62 sinks into the field, but by raising the float 62, i.e., by increasing the target planting depth L2, the float 62 rotates so that it is horizontal, allowing for more appropriate planting.

[0111] As described above, when the float 62 sags, the controller 100 lowers the seedling planting section 4, and when the float 62 is lifted, the controller 100 raises the seedling planting section 4. Therefore, the elevation control of the seedling planting section 4 based on the bending angle and the elevation control of the seedling planting section 4 based on the float angle θ2 are mutually exclusive controls, and the controller 100 tries to raise the seedling planting section 4 by changing the pitching angle as the bending angle increases, but the controller 100 tries to lower the seedling planting section 4 because the float 62 sags.

[0112] In the above conflicting controls, the controller 100 increases the dead zone of the float angle θ2 in response to an increase in the absolute value of the bending angle, and suppresses the raising and lowering of the seedling planting section 4 according to the float angle θ2 (makes the control insensitive). Specifically, when the float angle θ2 is within the dead zone, the controller 100 does not raise or lower the seedling planting section 4. In other words, the controller 100 prioritizes the raising and lowering control based on the bending angle, and ignores the raising and lowering control based on the angle of the float 62 to some extent.

[0113] Alternatively, when the absolute value of the bending angle is equal to or greater than a certain value, the controller 100 does not raise or lower the seedling planting unit 4 according to the float angle θ2. This is because when the traveling body 2 travels uphill or downhill at an angle equal to or greater than a certain value, the float 62 hangs down or is lifted up to the upper limit of the range in which it can rotate.

[0114] Next, calculation of the bending angle will be described with reference to Fig. 12. Fig. 12 is a diagram for explaining the distance L3 from the front wheels 10 of the traveling body 2 to the seedling planting section 4 in the front-rear direction.

[0115] The controller 100 sets the value obtained by dividing the front-rear distance L3 from the front wheels 10 of the traveling body 2 to the seedling planting section 4 by a natural number n of 2 or more as the fixed distance A (not shown). The controller 100 records the pitching angle every time the traveling body 2 moves by the fixed distance A, and keeps a log of the pitching angles up to the latest n. The controller 100 calculates the product of the latest n pitching angles and data of n rows and 1 column whose components sum to 0 as the bending angle. By setting the sum to 0 of the components of the data of n rows and 1 column, the controller 100 can control the elevation of the seedling planting section 4 mainly by the float 62, as on flat ground, after the traveling body 2 has completely entered a slope of a fixed angle.

[0116] In the data of n rows and 1 column, where b is a natural number smaller than n, the 1st row to the bth row are positive numbers, and the b+1th row to the nth row are negative numbers. This allows the controller 100 to calculate the turning angle so that the turning angle is increased until the rear wheel 11 approaches an uphill slope, and the turning angle is decreased after the rear wheel 11 approaches an uphill slope. The natural number b is set so that the wheelbase from the front wheel 10 to the rear wheel 11 is equal to A×b.

[0117] Next, a process for adjusting the vehicle speed of the traveling vehicle body 2 according to a modified example will be described with reference to Figs.

[0118] When the traveling vehicle body 2 travels uphill to leave a farm field, or when the work vehicle 1 is loaded onto a truck, it is required to keep the vehicle speed uniform (constant slow speed), but adjusting the vehicle speed by manually operating a lever is difficult. The controller 100 makes this task easier by providing a slow forward speed mode (second vehicle speed mode), in which the upper limit of the trunnion opening is restricted.

[0119] The work vehicle 1 is provided with a means for switching to the slow forward speed mode, and an operating tool for switching to the slow forward speed mode (setting switch 49 (see FIG. 5)). For example, the work vehicle 1 is provided with an electric mechanism for changing the trunnion opening degree by the trunnion arm of the HST 14, as the means for switching to the slow forward speed mode.

[0120] The setting switch 49 is desirably provided on the steering wheel 35 (see FIG. 2) or the like. Since the operator always holds the steering wheel 35 when loading the work vehicle 1 onto a truck, if the setting switch 49 is provided within reach of the operator's fingers while holding the steering wheel 35, operation becomes easy and the operator can work safely.

[0121] The controller 100 enables the input of the setting switch 49 only when the sub-transmission operation lever 37 is operated to the planting speed (low speed mode) or the moving speed (high speed mode). That is, the controller 100 disables the input of the setting switch 49 when the sub-transmission mechanism 16 is in a non-transmitting neutral state (a PTO state in which the power of the engine 30 is transmitted only to the seedling planting section 4). When the sub-transmission mechanism 16 is in a PTO state, there is no need to limit the upper limit of the trunnion opening, so the operator can prevent erroneous operation by restricting the input of the setting switch 49. In addition, if the input of the setting switch 49 is enabled when the sub-transmission operation lever 37 is operated to the neutral position, there is a risk that the traveling vehicle body 2 will run in reverse if the setting switch 49 is released while traveling uphill, but the operator can work safely by restricting the input of the setting switch 49. In addition, if the setting switch 49 is pressed when the sub-transmission operation lever 37 is operated to the neutral position, it is desirable to notify the operator that the input is disabled by a buzzer or the like.

[0122] The controller 100 judges whether the vehicle speed is constant at a slow speed in the slow forward mode by referring to the rotation speed sensor 90 of the rear wheel 11. For example, if the distance traveled within the target time calculated by referring to the rotation speed sensor 90 differs from the travel distance calculated from the target vehicle speed (constant slow speed), the controller 100 changes the trunnion opening so that the traveling body 2 travels at the target vehicle speed within the next target time. Note that the work vehicle 1 may calculate the distance traveled within the target time by referring to position information from GPS or GNSS instead of the rotation speed sensor 90.

[0123] When the traveling body 2 travels uphill, if the position of the trunnion arm (trunnion opening) is constant, the engine speed drops due to the tilt load. The work vehicle 1 changes (for example, increases) the trunnion opening when the setting switch 49 is pressed according to the angle of the uphill slope based on the pitching angle, so that the vehicle speed does not decrease.

[0124] The work vehicle 1 has a means for detecting the weight of the vehicle body, and changes (e.g., increases) the trunnion opening when the setting switch 49 is pressed according to the weight of the vehicle body. For example, a stroke sensor is provided on the suspension of the front wheel 10 as a means for detecting the weight of the vehicle body, and the controller 100 can calculate the load acting on the front wheel 10 from the spring constant and stroke amount (amount of expansion and contraction) of the suspension, and detect the weight of the vehicle from the calculated load.

[0125] If the front wheels 10 slip in a groove on a slope or the like when loading the work vehicle 1 onto a truck (for example, if the wheel rotation speeds of the left and right front wheels 10 differ by more than a specified value), the controller 100 stops integrating the rear wheel rotation speed and does not increase the trunnion opening. This allows the controller 100 to prevent the traveling body 2 from suddenly starting to move when it is not moving.

[0126] In addition, when slipping on a groove on a walking slope, it is possible that one of the front wheels 10 has fallen into the groove (or one of the front wheels 10 is floating). The stroke sensor of the controller 100 detects the left and right stroke amounts of the front wheels 10, stops accumulating the rear wheel rotation speed in response to the left and right stroke difference, and changes (e.g., reduces) the trunnion opening.

[0127] The controller 100 activates control when the traveling vehicle body 2 is tilted at a certain angle or more, i.e., when the traveling vehicle body 2 is traveling uphill and the front wheels 10 are slipping or one of the front wheels 10 is falling off (or one of the front wheels 10 is lifted off the ground).

[0128] The controller 100 is configured to be able to ignore the effect of unevenness of the field on the stroke sensor. In addition, because the rotation speed of the left and right front wheels 10 differs slightly due to unevenness of the field, the controller 100 is configured to be able to ignore the effect of unevenness of the field on the rotation speed sensor 90. This makes it possible for the controller 100 to prevent malfunction on flat ground.

[0129] Next, a motorized implant rod 60 according to a modified example will be described with reference to Figs. 13 to 15. Fig. 13 is a diagram for explaining the motorized implant rod 60. Figs. 14 and 15 are diagrams for explaining the arrangement of the motor control MDU and the main ECU. The main ECU is included in the controller 100.

[0130] The work vehicle 1 may be equipped with an electric planting rod 60 as the planting rod 58. The electric planting rod 60 shown in FIG. 13 has a planting claw 60a that rotates to plant seedlings, a motor 60b that drives the planting claw 60a, and a rotation angle sensor that measures the rotation angle of the planting claw 60a. The motor 60b transmits power to the planting claw 60a via a transmission unit 60d. The electric planting rod 60 is connected to a motor control MDU, and the rotation speed of the planting claw 60a is controlled by the motor control MDU. The motor control MDU is connected to the main control unit ECU and controlled by the main control unit ECU. The rotation angle sensor is, for example, a hall sensor, and is provided inside the motor 60b.

[0131] During orientation teaching (for example, when traveling forward and backward about 2 m) to teach the orientation during automatic traveling of the traveling body 2, the controller 100 determines the phase from the torque value when the planting claws 60a are rotated in reverse by the motor 60b in order to calibrate the rotation angle sensor. Each planting claw 60a is aligned to a predetermined position by determining the phase. At this time, since there is no one around the seedling planting unit 4, it is safe to automatically start calibrating the rotation angle sensor. Furthermore, unless orientation teaching is completed, planting with both positive rows or with plant spacing adjustment is not possible, so calibration at this timing is always performed without interfering with work.

[0132] The controller 100 may also calibrate the rotation angle sensor when it first receives a signal to raise the seedling planting unit 4 after the key is turned on. At this time, since there is no one around the seedling planting unit 4, it is safe to automatically start calibrating the rotation angle sensor. Even when the work vehicle 1 is in a field, by calibrating the rotation angle sensor when the seedling planting unit 4 starts to rise, it is possible to avoid calibration when the planting claws 60a are submerged in the soil (when the load for rotating the planting claws 60a is increased).

[0133] In addition, even if the controller 100 receives a signal to raise the seedling planting unit 4, if the sub-transmission mechanism 16 is at the travel speed (high-speed mode), the controller 100 does not calibrate the rotation angle sensor. When moving the work vehicle 1 or only loading the work vehicle 1, there are often obstacles around the seedling planting unit 4. Therefore, when the sub-transmission mechanism 16 is at the travel speed (high-speed mode), the controller 100 can improve safety by not rotating the planting claws 60a.

[0134] The controller 100 may also calibrate the rotation angle sensor at the start of so-called "pinch-up". At this time, since there is no one around the seedling planting unit 4, it is safe to automatically start calibrating the rotation angle sensor. When the basic method of pinch-up is used, since it is before the seedlings are placed in the seedling planting unit 4 and before the planting work starts, the controller 100 can calibrate the rotation angle sensor without picking up the seedlings.

[0135] The controller 100 stores the calibrated Hall sensor value in the motor control MDU for a predetermined time (for example, 2 hours). As a result, even if the key of the work vehicle 1 is temporarily turned off during rice planting work, the rotation angle sensor is recalibrated to operate the electric planting rod 60 and not remove the seedlings, allowing the rice planting work to be smoothly resumed.

[0136] As shown in FIG. 14, the motor-controlled MDU and main ECU are provided at position B inside the lifting link mechanism 3, and are covered with a removable and waterproof plate cover. Only the power supply is wired to the motorized planting rod 60. In this way, by separating the motor-controlled MDU and main ECU from the seedling tank 53, it is not necessary to wire a long harness for lateral movement of the seedling tank 53. The motor-controlled MDU and main ECU do not overlap with the rear wheels 11 in the traveling direction, and waterproofing from above is improved while maintaining the conventional configuration.

[0137] Alternatively, as shown in FIG. 15, the motor-controlled MDU and main ECU are provided at position C in the upper frame. Position C is located in the height direction between the extended seedling tank 68 (see FIG. 2) and the seedling feed belt 69 (see FIG. 2). In this way, with the work vehicle 1, the motor-controlled MDU and main ECU can be located in the space vacated by motorizing the planting rod 58, making wires and the like unnecessary, thereby making it possible to utilize dead space. In addition, position C is located outboard of the rear wheels 11 in the left-right direction. This makes it possible for the work vehicle 1 to prevent the motor-controlled MDU and main ECU from becoming dirty with mud.

[0138] Before calibrating the rotation angle sensor, the controller 100 may return the lateral feed of the seedlings in the opposite direction to the current direction by one scraping. In this way, the controller 100 can calibrate the rotation angle sensor without wasting any seedlings loaded in the seedling tank 53 by returning the lateral feed of the seedlings by one scraping. In addition, it is not necessary to maintain a power supply to store the position of the planting claws 60a. Note that the control of returning the lateral feed of the seedlings is performed only when the switch for detecting the remaining seedlings is pressed and the seedlings are in the seedling tank 53.

[0139] Next, a seedling tank 53 according to a modified example will be described with reference to Fig. 16 to Fig. 18. Fig. 16 is a diagram for explaining the arrangement of the light emitting device 61. Figs. 17 and 18 are diagrams for explaining the light emitting position D of the light emitting device 61.

[0140] As shown in FIG. 16, the work vehicle 1 is equipped with a seedling tank 53 on which a seedling mat is placed and which reciprocates in the left-right direction. The seedling tank 53 is provided with a light-emitting device 61 (e.g., an LED light tape) whose light-emitting position D moves downward according to the consumption of seedlings. The light-emitting device 61 is provided, for example, at the left end of the seedling tank 53. The seedling consumption amount is calculated based on the number of times the seedling tank 53 reciprocates, the seedling amount taken by the seedling planting section 4, and the compression rate of the seedlings, and the light-emitting position D of the light-emitting device 61 is an indication of the seedling consumption amount (estimated seedling consumption amount). This allows the worker U to visually check the estimated seedling consumption amount and the actual seedling consumption, and to know whether the actual seedling consumption amount is more or less than the estimated seedling consumption amount. The worker U can adjust the actual seedling consumption amount by adjusting the seedling amount taken or the number of seedlings used per unit area displayed on the monitor 86, using the estimated seedling consumption amount as a guide.

[0141] As shown in Fig. 17, the light-emitting device 61 illuminates a position that is a guide for the joints of the seedling mat, and displays that the light-emitting position D moves downward as planting proceeds. Alternatively, as shown in Fig. 18, the light-emitting device 61 illuminates a light-emitting range E of the length in which the seedlings are expected to be present, and displays that the light-emitting range E shortens downward as planting proceeds. The controller 100 uses the number of seedlings in the seedling tank 53 (obtained by operating a switch that counts the number of seedlings) and the expected seedling consumption amount to calculate the range of the length in which the seedlings are expected to be present, and causes the light-emitting device 61 to emit light.

[0142] The traveling vehicle body 2 is provided with a one-touch switch on the monitor 86. The one-touch switch is a switch that allows the worker U to compare the actual seedling consumption amount with the estimated seedling consumption amount displayed by the light-emitting device 61 and adjust the amount of seedlings to be harvested by increasing or decreasing it. The worker U visually checks the estimated seedling consumption amount with the actual seedling consumption amount, knows whether it is more or less, and can easily increase or decrease the amount of seedlings to be harvested using the one-touch switch. The worker U can also adjust the amount of seedlings to be harvested so that the final seedling consumption amount is accurate.

[0143] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0144] 1. Seedling transplanter (work vehicle) 2 Running vehicle 3 Lifting link mechanism 4 Seedling planting department 10 Front wheel 14 HST (Hydraulic Continuously Variable Transmission) 16 Sub-transmission mechanism 30 Engine 53 Seedling Tank 60 Electric implantable rod 60a Planting Claw 60b motor 61 Light emitting device 62 Float 90 Rotational speed sensor (travel distance sensor) 93 Link Angle Sensor 94 Float Angle Sensor 150 Position detection device (pitching angle sensor) D Light Emitting Position L1 Field depth L2 Target planting depth L3 Distance θ1 Link angle θ2 Float angle

Claims

1. A traveling vehicle body that travels in a field; a seedling planting section that plants seedlings taken from a seedling mat loaded on the rear of the traveling vehicle body in the field; A lifting link mechanism that supports the seedling planting unit so that it can be lifted and lowered; a pitch angle sensor for detecting a pitch angle of the traveling vehicle body; A control device that raises and lowers the seedling planting unit via the lifting link mechanism, The control device is a work vehicle that raises and lowers the seedling planting section in accordance with a change in the pitching angle.

2. The work vehicle according to claim 1 , wherein the control device raises and lowers the seedling planting unit so that the seedling planting unit is at a constant height relative to a surface of the field.

3. a link angle sensor for detecting a link angle which is an inclination angle of the lifting link mechanism; A float is provided under the seedling planting section to level the surface of the field and rotate due to the unevenness of the surface of the field; a float angle sensor for detecting a float angle, which is a rotation angle of the float; The control device includes: Calculating a field depth relative to a wheel contact surface of the traveling vehicle body based on the link angle, and setting a target value of a planting depth according to the field depth; A work vehicle as described in claim 1 or claim 2, wherein when the float hangs down more than a reference value of the float angle, the target value of the planting depth is reduced, and when the float is raised up more than the reference value, the target value of the planting depth is increased.

4. A float is provided under the seedling planting section to level the surface of the field and rotate due to the unevenness of the surface of the field; A float angle sensor that detects a float angle, which is a rotation angle of the float; a travel distance sensor for detecting a travel distance of the traveling vehicle body, The control device includes: Calculating a bending angle, which is an angle between a wheel contact surface of the traveling vehicle body and a float contact surface of the float, based on the transition of the pitching angle and the moving distance of the traveling vehicle body; A work vehicle as described in claim 1 or claim 2, wherein when the angle of bending is a positive angle when the wheel contact surface of the running body is on an uphill slope and a negative angle when the wheel contact surface of the running body is on a downhill slope, the target planting depth is increased as the angle of bending increases.

5. a travel distance sensor for detecting a travel distance of the traveling vehicle body, The control device includes: Calculating a bending angle, which is an angle between a wheel contact surface of the traveling vehicle body and a float contact surface of the traveling vehicle body, based on the transition of the pitching angle and the moving distance of the traveling vehicle body; 4. The work vehicle according to claim 3, wherein the dead zone of the float angle is increased in response to an increase in the absolute value of the bend angle, and the raising and lowering of the seedling planting section in response to the float angle is suppressed.

6. a travel distance sensor for detecting a travel distance of the traveling vehicle body, The control device includes: Calculating a bending angle, which is an angle between a wheel contact surface of the traveling vehicle body and a float contact surface of the traveling vehicle body, based on the transition of the pitching angle and the moving distance of the traveling vehicle body; The work vehicle according to claim 3 , wherein when the absolute value of the bending angle is equal to or greater than a certain value, the seedling planting section is not raised or lowered in accordance with the float angle.

7. The control device includes: A value obtained by dividing a distance in a front-rear direction from a front wheel of the traveling vehicle body to the seedling planting unit by a natural number n of 2 or more is set as a fixed distance; Recording the pitching angle every time the traveling vehicle body moves by the certain distance; 5. The work vehicle according to claim 4, wherein the bending angle is calculated by multiplying the most recent n pitching angles by data in n rows and 1 column, the sum of components of which is zero.

8. an auxiliary transmission mechanism for changing the traveling speed of the traveling vehicle body; a hydraulic continuously variable transmission that changes the speed of the power input from the engine of the traveling vehicle body and outputs the power, the control device has a slow forward mode in which an upper limit of a trunnion opening degree of the hydraulic continuously variable transmission device is limited, 3. The work vehicle according to claim 1, wherein the slow forward speed mode is disabled when the auxiliary transmission mechanism is in a non-transmitting neutral state.

9. The seedling planting unit includes an electric planting rod, The electric planting rod has a planting claw that rotates to plant seedlings, a motor that drives the planting claw, and a rotation angle sensor that detects the rotation angle of the planting claw. The work vehicle according to claim 1 or claim 2, wherein the control device determines a phase from a torque value when the motor rotates the planting claw in reverse in order to calibrate the rotation angle sensor during orientation teaching, which teaches the orientation of the vehicle body for automatic traveling.

10. The seedling mat is placed on a seedling tank that reciprocates in the left and right direction. The seedling tank is provided with a light emitting device whose light emitting position moves downward according to the consumption of seedlings, A work vehicle as described in claim 1 or claim 2, wherein the seedling consumption amount is calculated based on the number of times the seedling tank moves back and forth, the seedling amount taken from the seedling planting section, and the compression rate of the seedlings, and the light emitting position of the light emitting device serves as an indication of the seedling consumption amount.

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