Control device

Abstract

To provide a control unit which can suppress an idle state of a work vehicle.SOLUTION: A control unit (100) according to one aspect of an embodiment is a wheel attached on a right-left direction of a work vehicle (1) that works in a field, includes a position obtaining device (150) that obtains a current position and orientation of the work vehicle (1). When the work vehicle (1) rotates, the device detects if the wheel is in an idle state or not based on a change in an orientation detected by the position obtaining device (150). In the case of the idle state, the device detects if the idle state is solved or not.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a control device. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a control device that controls an operation device based on position information of a work vehicle in a field, thereby causing the work vehicle to travel autonomously (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-24541 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the prior art has room for improvement in terms of eliminating wheel spin in work vehicles.

[0005] The present invention has been made in view of the above, and has an object to provide a control device that can eliminate the spin state of a work vehicle. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a control device (100) according to one aspect of the embodiment is a control device for controlling a work vehicle (1) working in a field. To move on to the next process Turning When turning a ratio of the rotation speeds of the left and right wheels of the work vehicle (1) is calculated, and when the ratio deviates from a reference value by a predetermined value or more, a spinning state of the wheels is detected; a position acquisition device (150) for acquiring the current position and orientation of the work vehicle (1); In the case of the wheel spinning state, the position acquisition device (150) detects whether the wheel spinning state has been resolved based on the presence or absence of a change in position. [Effects of the Invention]

[0007] According to one aspect of the embodiment, it is possible to eliminate the spinning state of the work vehicle. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view showing a work vehicle. [Figure 2] FIG. 2 is a plan view showing the work vehicle. [Figure 3] FIG. 3 is a block diagram showing a control system centered on the control device of the seedling transplanter. [Figure 4] FIG. 4 is a block diagram showing the functional configuration of the controller. [Figure 5] FIG. 5 is an explanatory diagram of the autonomous driving of the seedling transplanter in a farm field. [Figure 6] FIG. 6 is a diagram illustrating the processing of the driving control unit. [Figure 7] FIG. 7 is a flowchart illustrating the process performed during spin. [Figure 8] FIG. 8 is a flowchart illustrating processing relating to mode transition. [Figure 9] FIG. 9 is a flowchart illustrating processing related to mode transition. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Overview of work vehicles) First, an overview of a work vehicle 1 according to a first 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 refers to the direction of travel of the work vehicle 1 when traveling straight, with the front side of the traveling direction being defined as "front" and the rear side being defined as "rear." The traveling direction of the work vehicle 1 is the direction from the driver's seat 41 toward the handlebars 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 the operator (also referred to as an operator) is seated in the operator'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, left-right direction, and 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 this 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 field work device and that receives seedlings in a field. As shown in Figures 1 and 2, the seedling transplanter 1 is equipped with the seedling planting unit 4, which 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] The main body of the fertilizer applicator 5 is disposed on the upper rear side of the traveling body 2. If the work vehicle 1 is not a seedling transplanter 1, it may be provided with a sowing device that supplies 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 also driving wheels. On the front side of the main frame 15 that forms the body skeleton 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 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 an HST (Hydro Static Transmission). In the following, a case where the continuously variable transmission is the HST 14 will be described.

[0017] An auxiliary transmission mechanism 16 is provided within the transmission case 13 to switch the driving mode of the traveling vehicle body 2 between high-speed mode for road driving and low-speed mode for planting seedlings, etc. 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 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.

[0018] 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 arranged laterally on the rear side of the main frame 15, and rear wheels 11 are attached to left and right rear axles 11b that protrude outward from the rear wheel gear cases 11a, respectively.

[0019] 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.

[0020] 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 vehicle body 2, are attached to the front of the seedling planting section 4.

[0021] 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 inside the transmission case 13, and then separated into traveling power and externally extracted power.

[0022] 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, a power steering mechanism 88 (see FIG. 3) of the handle 35, the lift cylinder 25, etc.

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

[0024] 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.

[0025] A side clutch 44 (see FIG. 3) that turns on and off the power transmission to the left and right drive shafts 42 is disposed upstream of the left and right drive shafts 42 in the power transmission direction. As shown in FIG. 1, a side clutch pedal 43a that turns on and off the left and right side clutches 44 is provided at the front lower part of the cockpit 41 and on one of the left and right sides.

[0026] 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.

[0027] A bonnet 39 with an operation panel 38 arranged on top for operating each section is provided on the upper front side of the traveling vehicle body 2. The operation panel 38 is provided with a monitor 86 (see FIG. 3) and the like.

[0028] The bonnet 39 is also provided with a handle 35 for steering the traveling vehicle body 2, a speed change control lever 36 for operating the HST 14 and the seedling planting section 4, and an auxiliary speed change control lever 37 for operating the auxiliary speed change mechanism 16.

[0029] An openable front cover 40 is provided in front of the hood 39. Inside the front cover 40, a fuel tank, a battery, and an interlocking mechanism that rotates 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. The front wheels 10 are, for example, steerable wheels that turn in response to steering of the handlebars 35.

[0030] An engine cover 30a that covers the top and sides of the engine 30 is provided behind the hood 39 and above the engine 30, and a pilot's seat 41 where the pilot sits is provided above the engine cover 30a.

[0031] The fertilizer applicator 5 is provided behind the driver's seat 41, at the rear end of the main frame 15. The driving force of the fertilizer applicator 5 is transmitted by a fertilizer transmission mechanism provided so as to face the fertilizer applicator 5 from one of the left and right rear wheel gear cases 11a.

[0032] Approximately horizontal floor steps 33 are formed on both the left and right sides of the lower part of the engine cover 30a and the hood 39. As shown in Fig. 2, the floor steps 33 are partially lattice-shaped, so that even if mud on the shoes of an operator walking on the floor steps 33 falls off, the fallen mud will fall into the field.

[0033] 2, a rear step 330 is connected to the rear of the floor step 33. The surface of the rear step 330 is preferably provided with an anti-slip finish, for example, with a pattern of multiple protrusions, to prevent feet from slipping during work.

[0034] In addition, on the front side of the traveling body 2 and on both the left and right sides, spare seedling frames 50 are provided, each with a seedling frame support 51 on which multiple spare seedling loading tables 52 are arranged at intervals in the vertical direction, so that work materials such as seedlings and fertilizer bags to be replenished in the seedling planting section 4 can be placed.

[0035] A seedling tank 53 for carrying 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 left and right. Seedling partition fences 54, which are long in the vertical direction, are placed on the seedling tank 53 at predetermined intervals in the horizontal direction. Below the seedling tank 53 is a seedling planting device 55 that picks up the loaded seedlings and plants them in the field.

[0036] The seedling planting device 55 plants eight rows at the same time, the same number as the number of rows to be planted separated by the seedling partition fence 54. 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.

[0037] In the fertilizer applicator 5, the fertilizer hopper 70 that stores the fertilizer is divided into the same number of sections as the number of working rows in the seedling planting section 4 (eight rows in the example shown in FIG. 2). Note that the eight-row fertilizer hopper 70 is long in the left-right direction, which reduces the convenience of adding fertilizer and attaching and detaching it, so it may have a so-called side fertilizer application structure, in which sections divided into four rows are lined up on each side.

[0038] Below the fertilizer hopper 70, a dispensing device 71 that supplies a set amount of fertilizer is provided for each row. Below the dispensing device 71, a ventilation duct 72 is provided in the left-right direction, through which conveying air passes to move the fertilizer. Below the dispensing device 71, a fertilizer hose 73 is provided to guide the fertilizer near the seedling planting position in the seedling planting section 4. Also, at one end of the ventilation duct 72, a blower 74 that is operated by an electric blower motor 76 to generate conveying air is provided.

[0039] 1 and 2, a center float 62C that slides on the field surface and two side floats 62L and 62R are provided rotatably about axes below the seedling planting section 4. The center float 62C and the left and right side floats 62L and 62R are sometimes collectively referred to as floats 62.

[0040] In addition, below the seedling planting section 4, and forward of the float 62, a ground leveling rotor 63 for leveling unevenness in the field surface is provided. 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.

[0041] 1, line-drawing markers 65 are provided on both the left and right sides of the seedling planting section 4. One of the markers 65 touches the ground on the field surface to form a groove that serves as a guide for traveling in the next work row (next process). When one of the markers 65 touches the ground, the other moves upward, and when the seedling planting section 4 is raised during rotation, both the left and right sides move upward, and when the seedling planting section 4 is lowered after rotation, one of the markers 65 moves upward and the other moves downward.

[0042] 1 and 2, a center mascot 66 that is long in the vertical direction is provided in the center of the left and right of the traveling vehicle body 2, and in front of the hood 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.

[0043] 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, causing the guide for going straight to disappear. In such cases, it is advisable to use the left and right side markers 19, which are located forward of the left and right line-drawing markers 65. In other words, by moving the left and right side markers 19 outward and positioning them above the planted seedlings, planting work can be performed in accordance with the planting of the seedlings in the previous work row.

[0044] As shown in FIG. 1, the seedling transplanter 1 is also equipped with a position acquisition device 150. The position acquisition device 150 acquires the current position and orientation of the seedling transplanter 1. The position acquisition device 150 includes, for example, an orientation sensor and a positioning means such as a Global Positioning System (GPS) or a Global Navigation Satellite System (GNSS). The position acquisition device 150 may be composed of multiple devices. The position acquisition device 150 may include a camera or an ultrasonic sensor, and may acquire a turning position in the field and detect the distance to the turning position.

[0045] For example, the position acquisition 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 acquires the current position and direction. The position acquisition device 150 is attached to the mounting stay 59, for example, and disposed above the traveling vehicle body 2.

[0046] A straight-line control program and a turning control program, which are created based on position information from position acquisition 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 position acquisition device 150, and the turning control program is stored, for example, in a turning control ECU 100b housed in hood 39. Note that straight-line control ECU 100a and turning control ECU 100b are included in control device 100 (see FIG. 3), which will be described later. Straight-line control ECU 100a and turning control ECU 100b may be stored in the same ECU.

[0047] (Seedling transplanter control system) Next, the control system of the seedling transplanter 1 will be described with reference to Fig. 3. Fig. 3 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.

[0048] The controller 100 is provided with a processing section having a CPU (Central Processing Unit) and the like, a memory section such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input / output section, which are interconnected to allow signals to be exchanged between them. The memory 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 memory section.

[0049] 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 HST14 motor 85, a line drawing marker lifting motor 87, a steering motor 95 (motor), and a differential lock switching motor 96.

[0050] The throttle motor 80 increases or decreases the rotation speed of the output shaft of the engine 30 by operating a throttle that adjusts the amount of air intake into the engine 30. The hydraulic control valve 81 controls the extension and retraction of the lift cylinder 25. The hydraulic control valve 82 controls the power steering mechanism 88. The planting clutch operating solenoid 83 operates the planting clutch 27a.

[0051] 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.

[0052] The HST14 motor 85 changes the rotation angle of the trunnion of the HST 14, thereby changing the tilt angle of the swash plate 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 Figure 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.

[0053] The differential lock switching motor 96 is a motor that switches between operating and deactivating a differential lock mechanism 97 (hereinafter referred to as a differential lock mechanism (same speed rotation mechanism)). The differential lock mechanism 97 locks the differential control that rotates the left and right front wheels 10 (or rear wheels 11) at different rotation speeds when turning. In other words, when the differential lock mechanism 97 is engaged, the differential control is locked and the left and right wheels rotate at the same rotation speed.

[0054] The controller 100 is connected to detection devices such as a rotation speed sensor 90, a steering amount sensor 91 (steering angle sensor), and an inclination sensor 92. Four rotation speed sensors 90 are provided corresponding to the left and right front wheels 10 and rear wheels 11, respectively, and detect the rotation speeds of the left and right front wheels 10 and rear wheels 11.

[0055] The steering amount sensor 91 detects the amount of operation 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 the value when the steering wheel 35 is in a preset straight-ahead position being used as a reference value. The tilt sensor 92 detects the tilt angle, which is the inclination of the traveling vehicle body 2.

[0056] In addition, signals are input to the controller 100 as operation signals from the speed change operation lever 36, the auxiliary speed change operation lever 37, the autonomous driving switch 46, the planting section lifting / lowering switch 47, the automatic turning switch 48, the line drawing marker automatic lifting / lowering switch 49, etc.

[0057] The autonomous driving changeover switch 46 is a switch that switches whether or not autonomous driving is performed. Specifically, the autonomous driving changeover switch 46 is a switch that switches the driving mode between the autonomous driving mode and the manual driving mode.

[0058] The planting section lifting / lowering switch 47 is a switch that switches whether to lift or lower the seedling planting section 4. The planting section lifting / lowering switch 47 can be changed to the "up" and "down" positions.

[0059] When the planting unit lift switch 47 is in the "up" position, the seedling planting unit 4 rises to a predetermined non-working position and the seedling planting device 55 stops, putting it into a non-working state. When the planting unit lift switch 47 is in the "down" position, the seedling planting unit 4 descends to a predetermined working position and the seedling planting device 55 operates, putting it into a working state. In other words, the planting unit lift switch 47 is a switch that detects the working state of the seedling planting unit 4. Note that a separate switch that detects the working state of the seedling planting unit 4 may also be provided.

[0060] The automatic line drawing marker lifting / lowering switch 49 is a switch that switches whether or not the line drawing marker 65 is automatically lifted / lowered in conjunction with the amount of operation of the handlebars 35, i.e., the amount of steering of the front wheels 10. When the automatic line drawing marker lifting / lowering switch 49 is "ON," control is executed to automatically lift / lower the line drawing marker 65 in conjunction with the amount of steering. On the other hand, when the automatic line drawing marker lifting / lowering switch 49 is "OFF," control is not executed to automatically lift / lower the line drawing marker 65 in conjunction with the amount of steering.

[0061] The automatic turning selector switch 48 is a switch that switches whether or not automatic turning is enabled. When the automatic turning selector switch 48 is set to "ON," automatic turning is enabled. When the automatic turning selector switch 48 is set to "OFF," automatic turning is disabled. When the automatic turning selector switch 48 is set to "OFF," automatic turning is not performed even if the conditions for performing automatic turning are met.

[0062] The functional configuration of the controller 100 will now be described with reference to Fig. 4. Fig. 4 is a block diagram showing the functional configuration of the controller 100.

[0063] As shown in FIG. 4, the controller 100 includes a detection unit 101, a slip detection unit 102, a drive control unit 103, and a travel control unit 104.

[0064] The detection unit 101 detects the rotation speeds of the front wheels 10 and rear wheels 11 during turning based on the detection results of the rotation speed sensor 90. Specifically, the detection unit 101 detects the rotation speeds of the left front wheel 10, the right front wheel 10, the left rear wheel 11, and the right rear wheel 11 when the steering angle of the front wheels 10 is equal to or greater than a predetermined angle. In other words, the detection unit 101 detects the rotation speeds of the front wheels 10 and the rear wheels 10 when differential control is initiated.

[0065] The spin detection unit 102 detects a spinning state of the front wheels 10 based on a left-right difference, which is the difference in the rotation speeds of the left and right front wheels 10. Specifically, the spin detection unit 102 calculates the ratio of the rotation speed of the right front wheel 10 to the rotation speed of the left front wheel 10 as the left-right difference. Alternatively, the spin detection unit 102 calculates the ratio of the rotation speed of the left front wheel 10 to the rotation speed of the right front wheel 10 as the left-right difference. Note that the spin detection unit 102 may also calculate the difference between the rotation speed of the left front wheel 10 and the rotation speed of the right front wheel 10 as the left-right difference.

[0066] The spin detection unit 102 detects a spin state when the ratio of the rotation speeds, which is the difference between the left and right wheels, deviates from a reference value by a predetermined value or more. The reference value is set to a value corresponding to the steering angle of the front wheels 10. In other words, when the ratio of the rotation speeds is less than a predetermined value from the reference value, the spin detection unit 102 detects that the vehicle is turning normally due to differential control, and when the ratio of the rotation speeds deviates from the reference value by a predetermined value or more, it detects that either the left or right front wheel 10 is spinning. Note that when the rear wheels 11 are differentially controlled, the spin detection unit 102 detects the spin state of the rear wheels 11.

[0067] In this way, the controller 100 according to the embodiment can detect a spin state based on the rotation speed of the left and right wheels (front wheel 10 or rear wheel 11), thereby detecting the spin state without acquiring position information from the position acquisition device 150. That is, the controller 100 according to the embodiment can detect a spin state at low cost.

[0068] In addition, when both the left and right front wheels 10 are in a spinning state, the spin detection unit 102 detects that both the left and right front wheels 10 are in a spinning state because the positions detected by the position detection device 150 do not change.

[0069] When the slip detection unit 102 detects a slip state, the drive control unit 103 drives the differential lock switching motor 96 to operate the differential lock mechanism 97 and set it to the on state.

[0070] When the differential lock mechanism 97 of the front wheels 10 is activated by the drive control unit 103, the spin detection unit 102 detects whether the spin state of the front wheels 10 has been resolved based on the rotation speed of the rear wheels 11, which are driven wheels (a state in which the clutch is disengaged from the drive shaft) during turning. Specifically, when the spin detection unit 102 detects that the rear wheels 11, which are driven wheels, are rotating, it detects that the spin state has been resolved, and when it detects that the rear wheels 11 are stopped, it detects that the spin state is continuing.

[0071] In this way, by operating the differential lock mechanism 97 when the front wheels 10 are in a spinning state, the left and right front wheels 10 rotate at the same rotation speed, so that the spinning state can be eliminated with high precision.

[0072] If the spinning state of the front wheels 10 is not resolved after the differential lock mechanism 97 of the front wheels 10 is activated by the drive control unit 103, the spin detection unit 102 switches the rear wheels 11 from driven wheels to drive wheels. Specifically, the spin detection unit 102 switches the rear wheels 11 to drive wheels by connecting a clutch to the drive shaft of the rear wheels 11. In other words, if the spinning state of the front wheels 10 is not resolved despite the activation of the differential lock mechanism 97, the spinning state can be resolved with high accuracy by forcibly switching to four-wheel drive.

[0073] The functions of the detection unit 101, the slip detection unit 102, and the drive control unit 103 may be configured to be switchable on and off using a selector switch (not shown). Such a selector switch is provided, for example, near the driver's seat 41 of the traveling vehicle body 2.

[0074] The changeover switch is also used to remotely operate the seedling transplanter 1 (remotely adjust various working machines) while the seedling transplanter 1 is automatically traveling. Remote control device It should be noted that the configuration may be such that the switching is possible. Remote control device are used to control the amount of seedlings taken in the planting section 4, the planting depth, and switching of the seedling rails.

[0075] In addition, Remote control device Alternatively, when the four-wheel drive is forced into the four-wheel drive state due to a spin or the like, the four-wheel drive control may be cancelled (the rear wheels 11 may be switched from driving wheels to driven wheels).

[0076] Furthermore, the controller 100 may determine whether the seedling transplanter 1 is moving, including whether it is in an idling state, based on the position information detected by the position acquisition device 150.

[0077] The traveling control unit 104 executes an autonomous traveling mode in which the traveling vehicle body 2 performs work while automatically traveling (autonomous traveling) based on the current position information of the traveling vehicle body 2 acquired from the position acquisition device 150 and the like.

[0078] (Autonomous driving mode) Here, autonomous driving (automatic driving) including automatic turning in a field by the seedling transplanter 1 will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram of the autonomous driving of the seedling transplanter 1 in a field. The driving control unit 104 has an autonomous driving mode in which the steering motor 95 (see Fig. 3) is controlled to operate the handlebars 35 (see Fig. 3) 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.

[0079] As shown in Figure 5, in the autonomous driving mode, the seedling transplanter 1 automatically performs seedling planting work in the field by repeatedly moving straight and turning along the planned driving route. As described above, the driving control unit 104 acquires information on the current position of the seedling transplanter 1 and information on the turning position using the position acquisition device 150 located above the traveling body 2.

[0080] The seedling transplanter 1 plants seedlings while traveling back and forth within a predetermined work area in the field. In this case, for straight travel, the travel control unit 104 executes the automatic straight travel mode, so that the machine automatically travels along a set straight travel path L1. For turning travel, the travel control unit 104 executes the automatic turning mode, so that the machine automatically turns along a turning travel path L2.

[0081] The straight-ahead travel path L1 is parallel to a reference line L0, which serves as a travel reference. The reference line L0 is set in the field in accordance with the planting direction of the seedlings. The travel control unit 104 acquires the start and end positions of the straight-ahead travel as a reference start point (point A) and a reference end point (point B), respectively, and stores the line segment connecting points A and B as the reference line L0.

[0082] The travel control unit 104 controls the steering amount of the handle 35 to be a predetermined value while the seedling transplanter 1 is turning. The steering motor 95 is controlled so that the steering amount is the predetermined steering amount. In this case, the travel control unit 104 executes the process regardless of the position information acquired by the position acquisition device 150. The predetermined steering amount is a value set in advance. The predetermined steering amount is set depending on the type of seedling transplanter 1, etc. The predetermined steering amount is set so that the transition from automatic turning to automatic straight traveling is performed smoothly.

[0083] If the position of the seedling transplanter 1 after automatic turning deviates from the automatic straight-line travel path L1 of the next process, the automatic turning is adjusted to match the automatic straight-line travel path L1 of the next process, resulting in significant wobble of the traveling vehicle body 2. Furthermore, for example, the operator must operate the steering wheel 35 and align the rows to match the automatic straight-line travel path L1 of the next process, which increases the burden on the operator. Furthermore, there is a risk that the traveling posture of the seedling transplanter 1 will not be lost. In consideration of these points, the predetermined steering amount is set so that the transition from automatic turning to automatic straight-line travel is smooth.

[0084] The travel control unit 104 may control the steering motor 95 so that the seedling transplanter 1 reaches any desired position on the set turning travel path L2 based on the position information acquired by the position acquisition device 150 while the seedling transplanter 1 is turning. The controller 100 may also perform automatic turning by combining the above-mentioned two automatic turning modes.

[0085] The travel control unit 104 controls the steering motor 95 so that after turning by automatic turning, the seedling transplanter 1 reaches the planting start position by automatic straight travel in the next process.

[0086] When performing autonomous driving, the driving control unit 104 controls the steering motor 95 based on the steering amount of the steering wheel 35 detected by the steering amount sensor 91. Specifically, the driving control unit 104 performs autonomous driving so that the traveling direction based on the steering amount of the steering wheel 35 detected by the steering amount sensor 91 is along the reference direction, which is the direction of the reference line L0.

[0087] Here, we will explain the case where the seedling transplanter 1 transitions to the autonomous travel mode when it is located on the straight travel path L1. When the seedling transplanter 1 is located on the straight travel path L1, the travel control unit 104 transitions to the autonomous travel mode (automatic straight travel mode) when the seedling transplanter 1 satisfies a predetermined condition.

[0088] Specifically, the driving control unit 104 transitions from the manual driving mode to the autonomous driving mode when the following conditions (1) to (4) are met. (1) The location information is correctly detected by the location acquisition device 150. (2) The aircraft attitude is less than a specified angle (e.g., 8 degrees). (3) The sub-transmission is not in high-speed mode. (4) The direction of travel is not the backward direction. If the traveling mode is changed to the autonomous traveling mode while the traveling direction of the seedling transplanter 1 is deviated from the reference direction, the traveling control unit 104 cancels the autonomous traveling mode and changes the mode to the manual traveling mode after a predetermined first time period has elapsed. This point will be explained using FIG. 6.

[0089] Fig. 6 is a diagram showing the processing of the travel control unit 104. Fig. 6 shows a case where the traveling direction (solid arrow) of the seedling transplanter 1 deviates from the reference direction (direction of the reference line L0) by a predetermined deviation angle α.

[0090] As shown in Figure 6, when the autonomous driving mode is entered when the deviation angle α of the travel direction of the seedling transplanter 1 from the reference direction is equal to or greater than a predetermined angle, the driving control unit 104 cancels the autonomous driving mode after a predetermined first time period has elapsed. The first time period is set according to the deviation angle α. Specifically, the larger the deviation angle α, the shorter the first time period is set, and the smaller the deviation angle α, the longer the first time period is set.

[0091] That is, the travel control unit 104 takes into consideration that the traveling direction of the seedling transplanter 1 is in the process of returning to the reference direction, and waits for the first time period until the deviation angle α returns to less than the predetermined angle. More specifically, the smaller the deviation angle α, the higher the possibility that the angle will return to less than the predetermined angle, so the first time period is made longer, and the larger the deviation angle α, the lower the possibility that the angle will return to less than the predetermined angle, so the first time period is made shorter.

[0092] This allows for a mode transition with a first time margin, even if the vehicle accidentally switches to autonomous driving mode too early, for example, when the direction of travel returns to the reference direction immediately after an automatic turn.

[0093] Note that while Figure 6 describes mode transitions using an example of the deviation angle α, similar processing can also be performed with the planting unit 4, which is a work machine. Specifically, if the planting unit 4 transitions to autonomous driving mode when its height position relative to the field is at or above a predetermined height, the travel control unit 104 cancels the autonomous driving mode after a predetermined second time has elapsed. Note that the second time is set according to the height position. Specifically, the higher the height position (the farther from the predetermined height position), the shorter the second time is set, and the lower the height position (the closer to the predetermined height position), the longer the second time is set. Note that the predetermined height position corresponds to the height of the working position of the planting unit 4.

[0094] In other words, the travel control unit 104 takes into consideration that the height position of the planting unit 4 is in the process of returning to below the predetermined height, and waits for the second time period to wait for the height position to return to below the predetermined height. More specifically, the lower the height position, the higher the possibility of returning to below the predetermined height, so the second time period is made longer, and the higher the height position, the lower the possibility of returning to below the predetermined height, so the second time period is made shorter.

[0095] This makes it possible to transition between modes with a margin of only the second time, even if the planting section 4 accidentally switches to autonomous driving mode too early when its height position returns to below a predetermined height, for example.

[0096] Next, the processing executed by the controller 100 according to the embodiment will be described with reference to the flowcharts of Figures 7 to 9. Figure 7 is a flowchart illustrating the processing executed during spinning. Figures 8 and 9 are flowcharts illustrating the processing related to mode transition.

[0097] As shown in FIG. 7, the controller 100 detects the rotation speed of each of the left and right front wheels 10 (step S101).

[0098] Next, the controller 100 determines whether the front wheels 10 are in a spinning state based on the difference between the left and right rotation speeds (step S102).

[0099] If the wheels are in a spinning state (step S102: Yes), the controller 100 activates the differential lock mechanism 97 of the front wheels 10 (step S103). If the wheels are not in a spinning state (step S102: No), the controller 100 proceeds to step S101.

[0100] Next, the controller 100 detects the rotation of the rear wheels 11, which are driven wheels (step S104).

[0101] The controller 100 determines whether or not the spinning state has been resolved based on the result of the rotation detection of the rear wheel 11 (step S105).

[0102] If the idling state has been resolved (step S105: Yes), the controller 100 ends the process, and if the idling state has not been resolved (step S105: No), the controller 100 returns to step S104.

[0103] Next, as shown in FIG. 8, the controller 100 acquires a reference direction in which the seedling transplanter 1 automatically moves straight ahead (step S201).

[0104] Next, the controller 100 transitions to the autonomous driving mode when a predetermined condition is satisfied (step S202).

[0105] Next, the controller 100 calculates the deviation angle α of the traveling direction from the reference direction (step S203).

[0106] Next, the controller 100 determines whether the deviation angle α is equal to or greater than a predetermined angle (step S204).

[0107] If the deviation angle α is equal to or greater than the predetermined angle (step S204: Yes), the controller 100 determines whether the deviation has been eliminated within the first hour (step S205).

[0108] If the deviation is eliminated within the first hour (step S205: Yes), the controller 100 continues the autonomous driving mode (step S206) and ends the process.

[0109] Furthermore, if the deviation angle α is less than the predetermined angle (step S204: No), the controller 100 ends the process.

[0110] Furthermore, if the deviation is not resolved within the first hour (step S205: No), the controller 100 cancels the autonomous driving mode (step S207) and ends the process.

[0111] Next, as shown in FIG. 9, the controller 100 acquires a reference direction in which the seedling transplanter 1 automatically moves straight ahead (step S301).

[0112] Next, the controller 100 transitions to the autonomous driving mode when a predetermined condition is satisfied (step 3202).

[0113] Next, the controller 100 detects the height position of the planting unit 4, which is a work machine (step S303).

[0114] Next, the controller 100 determines whether the height position is equal to or higher than a predetermined height (step S304).

[0115] If the height position is equal to or greater than the predetermined height (step S304: Yes), the controller 100 determines whether the height position has become less than the predetermined height within a second time period (step S305).

[0116] If the height becomes less than the predetermined height within the second time period (step S305: Yes), the controller 100 continues the autonomous driving mode (step S306) and ends the process.

[0117] Furthermore, if the height position is below the predetermined height (step S304: No), the controller 100 ends the process.

[0118] Furthermore, if the height does not become less than the predetermined height within the second hour (step S305: No), the controller 100 cancels the autonomous driving mode (step S307) and ends the process.

[0119] As described above, the controller 100 according to the embodiment includes a detection unit 101 and a wheel spin detection unit 102. The detection unit 101 detects the rotation speed of each of the wheels provided on the left and right sides of a work vehicle used in farm work, which wheels are capable of differential control, rotating the left and right wheels at different rotation speeds when turning. The wheel spin detection unit 102 detects a wheel spin state based on the difference in rotation speed between the left and right wheels. This makes it possible to detect a wheel spin state at low cost.

[0120] Further advantages and modifications will readily occur to those skilled in the art. Therefore, 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 their equivalents. [Explanation of symbols]

[0121] 1. Seedling transplanter (work vehicle) 2 Running vehicle 4 Seedling planting department 10 Front wheels 11 Rear wheel 35 Handle (steering device) 38 Control Panel 91 Steering amount sensor (steering angle sensor) 95 Steering motor (motor) 100 Controller (control device) 101 Detection unit 102 Idling detection unit 103 Drive control unit 104 Travel control unit

Claims

1. When a work vehicle working in a field turns to move to a next process, a ratio of the rotation speeds of the left and right wheels of the work vehicle is calculated, and when the ratio deviates from a reference value by a predetermined value or more, a state of wheel spin is detected; a position acquisition device for acquiring the current position and orientation of the work vehicle; When the wheels are in a spinning state, the position acquisition device determines whether or not there is a change in position. The control device detects whether or not the wheel has stopped spinning.

2. The vehicle is equipped with a differential that rotates the left and right front wheels at different rotation speeds when turning, and a drive control unit that operates a differential lock mechanism that locks the differential of the front wheels when the spin state is detected, If the slipping state is not resolved even when the differential lock mechanism is operating, the rear wheel on the inside of the turning wheel, which is the driven wheel, is switched from the driven wheel to the driving wheel during turning, a remote control device for remotely operating the work vehicle; The remote control device can switch the rear wheel on the inside of the turning wheel, which is the driven wheel, to the drive wheel during turning regardless of whether the wheel is spinning or not, and can operate the differential lock mechanism at all times.

2. The control device according to claim 1, wherein the remote control device can switch the rear drive wheels to driven wheels and release the operation of the differential lock mechanism.

Images