Work vehicle

Abstract

To provide a useful work vehicle.SOLUTION: A rice transplanter 1 (a work vehicle) automatically travels while specifying its own position by using a satellite positioning system. An operation member 50 (a display surface) includes an A button 53 (a first indicator) for a registration operation of a start point of a reference route of automatic traveling, a B button 52 (a second indicator) for a registration operation of an end point of the reference route, and an AUTO button 51 (a third indicator) to be operated when starting and stopping the automatic traveling, disposed thereon. The A button 53 (the first indicator) and the B button 52 (the second indicator) are horizontally disposed side by side, and display positioning accuracy based on a positioning signal from the satellite positioning system. When the positioning accuracy becomes lower than prescribed accuracy during the automatic traveling, the automatic traveling is not continued.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a work vehicle that performs autonomous driving using a satellite positioning system. [Background technology]

[0002] Conventionally, a work vehicle that automatically travels in a field using a satellite positioning system is known. Since automatic travel requires highly accurate identification of the vehicle's own position, the vehicle is configured to stop automatic travel when the positioning state deteriorates due to the number of satellites with which it communicates or poor communication (e.g., the presence of an obstacle). The positioning state is one of the criteria for determining whether automatic travel can be continued or not, so it is useful to notify the operator of the positioning state as shown in Patent Document 1. However, since the positioning state frequently changes depending on the situation, if the notification is changed frequently in response to the change, it may give the operator the misunderstanding that the current positioning state is unstable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 63-067887 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in consideration of the above problems, and has an object to provide a work vehicle that can prevent the operator from being misled when the positioning state changes frequently. [Means for solving the problem]

[0005] The work vehicle of the present invention is a work vehicle that performs automatic driving while determining its own position using a satellite positioning system, and is equipped with a positioning unit that receives a positioning signal from the satellite positioning system and measures its own position based on the positioning signal, a control unit that determines the positioning accuracy based on the positioning state of the positioning unit and allows automatic driving when the positioning accuracy is equal to or greater than a predetermined accuracy, and a notification unit that executes a first notification indicating that the positioning accuracy is a first accuracy that is equal to or greater than the predetermined accuracy, and a second notification indicating that the positioning accuracy is a second accuracy that is equal to or greater than the predetermined accuracy, in accordance with control by the control unit, and is configured to continue executing the first notification until a second predetermined time has elapsed when a condition for the positioning accuracy to transition from the first accuracy to the second accuracy is met within a first predetermined time after executing the first notification in response to the transition to the first accuracy, and to continue executing the first notification until a second predetermined time has elapsed, and to terminate the first notification and execute the second notification after the second predetermined time has elapsed.

[0006] If the positioning accuracy (first and second accuracy) at which automatic driving is permitted continues, there is no problem in continuing automatic driving even if the positioning state changes continuously. Therefore, in this work vehicle, when the positioning state changes continuously within the first predetermined time as described above, the notification is not changed immediately, but is changed after the second predetermined time has elapsed. This makes it possible to prevent the operator from being misled when the positioning state changes frequently.

[0007] It is preferable that the control unit is configured to prohibit the start of automatic driving while permitting the continuation of automatic driving when the positioning accuracy is a third accuracy lower than the first accuracy and the second accuracy, and the notification unit executes a third notification indicating that the positioning accuracy is the third accuracy according to the control by the control unit, and when a condition for the positioning accuracy to transition from the second accuracy to the third accuracy is satisfied within a third predetermined time after executing the second notification according to the transition to the second accuracy, continues to execute the second notification until a fourth predetermined time has elapsed, and terminates the second notification and executes the third notification after the fourth predetermined time has elapsed. Since the notification is handled in the same manner as the high-precision positioning accuracy (first and second accuracy) for the positioning accuracy (third accuracy) for which the start of automatic driving is not permitted but the continuation (continuation) of automatic driving is permitted, it is possible to more effectively prevent the operator from being misled.

[0008] It is preferable that the control unit prohibits the start and continuation of automatic driving when the positioning accuracy is a fourth accuracy lower than the first accuracy and the second accuracy, and the notification unit executes a fourth notification indicating that the positioning accuracy is the fourth accuracy according to control by the control unit, and immediately executes the fourth notification when a condition for the positioning accuracy to transition to the fourth accuracy is satisfied. By immediately changing the notification to a positioning accuracy (fourth accuracy) for which the start and continuation of automatic driving are prohibited, it is possible to notify an operator without delay that the cause of the end of automatic driving is the deterioration of the positioning state.

[0009] The vehicle is preferably equipped with a steering wheel provided in front of the driver's seat, an operating member having an indicator for instructing the start of automatic driving and a display constituting the notification unit, and an arm member supporting the operating member, and the operating member supported by the arm member is preferably configured to be movable within a range from the front end to the rear end of the steering wheel in a plan view, but not to be movable rearward beyond the rear end of the steering wheel in a plan view. The operating member being movable within the above range is convenient for the operator to instruct the start of automatic driving and to check the positioning accuracy. In addition, since the operating member cannot be moved rearward beyond the rear end of the steering wheel, it is possible to prevent the operating member from deteriorating visibility. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a left side view of a rice transplanter which is an example of a work vehicle according to the present invention. [Diagram 2] Plan view showing part of the rice transplanter [Diagram 3] A perspective view of the driving operation unit from the front left [Figure 4] FIG. 1 is a diagram showing an operation surface of an operation member; [Diagram 5] Block diagram showing the main components related to autonomous driving [Figure 6] A table showing an example of the relationship between positioning accuracy and automatic driving and notification [Figure 7A] A diagram explaining the timing for changing notifications [Figure 7B] A diagram explaining the timing for changing notifications [Figure 7C] FIG. 13 is a diagram illustrating a modification of the timing for changing the notification. [Figure 7D] FIG. 13 is a diagram illustrating a modification of the timing for changing the notification. [Figure 7E] FIG. 13 is a diagram illustrating a modification of the timing for changing the notification. [Figure 7F] FIG. 13 is a diagram illustrating a modification of the timing for changing the notification. [Figure 8] A diagram explaining the timing for changing notifications [Figure 9]FIG. 13 is a diagram showing an example of a lighting pattern of a light-emitting portion of an operation member; [Figure 10] A block diagram showing an example of a control structure for autonomous driving [Figure 11] A block diagram showing a modified example of a control structure for automatic driving. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the present invention will be described with reference to the drawings. In this embodiment, a rice transplanter 1 shown in FIG. 1 is shown as an example of a riding type work vehicle. However, the work vehicle according to the present invention is not limited to a rice transplanter, and may be, for example, an agricultural work vehicle such as a tractor, a combine harvester, or a seedling transplanter. Alternatively, it may be a civil engineering work vehicle or a snowplow.

[0012] [Overall structure of the rice transplanter] First, the overall structure of the rice transplanter 1 will be briefly described. In FIG. 1, the front-rear and up-down directions of the rice transplanter 1 are indicated by arrows, and the direction perpendicular to the paper surface is the left-right direction. The rice transplanter 1 has a traveling section 10 and a planting section 20 as a working section. The planting section 20 is disposed behind the traveling section 10. The planting section 20 is connected to the rear of the traveling section 10 via a lifting mechanism 21 so that it can be raised and lowered freely. The rice transplanter 1 is configured so that it can perform seedling planting (rice planting) work in which seedlings are planted by the planting section 20 while traveling within a farm field using the traveling section 10.

[0013] The traveling unit 10 has a traveling body 2, a pair of left and right front wheels 3 that support the traveling body 2, and a pair of left and right rear wheels 4. The front wheels 3 are attached to front axles extending to both the left and right sides from a front axle case 5. The front axle case 5 is provided on the side of a transmission case 8 and is supported at the front part of the traveling body 2. The rear wheels 4 are attached to rear axles extending to both the left and right sides from a rear axle case 6. The rear axle case 6 is provided at the rear end of a cylindrical frame 9 that protrudes rearward from the transmission case 8 and is supported at the rear part of the traveling body 2.

[0014] An engine 7, which is a drive source, is mounted on the front of the traveling body 2. The engine 7 is covered by a bonnet 11. The power of the engine 7 is transmitted to a transmission case 8 disposed behind the engine 7, and is transmitted to the front wheels 3 and the rear wheels 4 via the transmission case 8. By transmitting the power to the front wheels 3 and the rear wheels 4 to rotate them, the traveling part 10 can travel in the forward and backward directions.

[0015] A link frame 17 is erected at the rear end of the traveling body 2. The planting unit 20 is connected to the link frame 17 via a lifting mechanism 21 so that it can be raised and lowered. The lifting mechanism 21 has a lower link 21a and a top link 21b. The lower link 21a is connected to the rod tip of a hydraulic lifting cylinder 22. The cylinder base end of the lifting cylinder 22 is supported on the upper rear part of the cylindrical frame 9 so that it can rotate up and down. By extending and retracting the lifting cylinder 22, the lifting mechanism 21 rotates in the vertical direction, and the planting unit 20 is configured to rise and fall.

[0016] The planting section 20 comprises a planting input case 23 to which power is transmitted from the engine 7 via the transmission case 8 and PTO shaft (power transmission shaft) 18, a plurality of planting transmission cases 24 connected to the planting input case 23, a seedling planting mechanism 25 provided at the rear end of each planting transmission case 24, and a seedling carrier 26 on which seedling mats are placed. Spare seedlings to be fed (supplied) to the planting section 20 are placed on spare seedling carriers 15 arranged on both the left and right sides of the bonnet 11. The spare seedling carriers 15 are supported by support frames 16 (spare seedling supports) erected on both the left and right sides of the front of the traveling body 2.

[0017] The seedling planting mechanism 25 is provided with a rotary case 28 having two planting claws 27, 27 for one row. As the rotary case 28 rotates, the two planting claws 27, 27 alternately pick up the seedlings from the seedling mat and plant them in the field. Since the rice transplanter 1 of this embodiment is an eight-row planting rice transplanter, it is provided with four sets of planting transmission cases 24 for eight rows (one set for two rows), and the seedling carrier 26 is also configured for eight-row planting. However, the rice transplanter 1 is not limited to this, and may be, for example, a six-row or ten-row planting rice transplanter.

[0018] Side markers 29 are provided on the left and right outer sides of the planting unit 20. The side markers 29 have a marker wheel 29w for stripping stripes and a marker arm 29a that rotatably supports the marker wheel 29w. The base end of the marker arm 29a is supported on the left and right outer sides of the planting unit 20 so that it can rotate left and right. The side marker 29 is configured to be displaceable between a landing position in which the marker wheel 29w is lowered to form a trajectory on the paddy field surface that will be the reference for the next process, and a non-landing position (see Figure 1) in which the marker wheel 29w is raised and separated from the paddy field surface.

[0019] A driving operation unit 30 is provided in the center of the traveling body 2 in the front-rear direction. The operator gets on a work step 12 (body cover) provided on the upper surface side of the traveling body 2, and drives and operates the rice transplanter 1 at the driving operation unit 30. An operation panel 31 is provided in front of the driving operation unit 30. The operation panel 31 is arranged on the rear upper surface side of the bonnet 11. A plurality of operating tools including a steering handle 32 and a main speed change lever 33 are arranged on the operation panel 31. A driver's seat 14 is installed behind the operation panel 31 via a seat frame 13.

[0020] On both the left and right sides of the bonnet 11, a plurality of (four in this embodiment) spare seedling tables 15 are supported by a pair of support frames 16, 16 spaced apart in the front-rear direction. A connecting frame 40 that is roughly L-shaped when viewed from the side is connected to the upper ends of the pair of support frames 16, 16. A unit frame 42 is connected to the upper end of the connecting frame 40 via an intermediate frame 41 that extends in the vertical direction. The unit frame 42 is rotatably connected to the upper parts of the left and right intermediate frames 41. A positioning unit 43 is fixed to the unit frame 42 as a positioning section.

[0021] The positioning unit 43 receives a positioning signal from a global navigation satellite system (GNSS) and identifies the vehicle's position based on the positioning signal. The rice transplanter 1 performs automatic driving while identifying the vehicle's position using the satellite positioning system. The rice transplanter 1 can autonomously drive straight along a target route that is generated parallel to the reference route by generating a linear reference route (teaching route) that serves as a reference for straight-line driving. Straight-line assistance work by automatic driving requires the registration of a start point of the reference route called point A, the registration of an end point of the reference route called point B, and the operation of turning on (starting) / off (stopping) automatic driving. Note that the rice transplanter 1 may autonomously drive not only straight-line driving but also a turning route connecting the target routes.

[0022] In this embodiment, an example is shown in which DGPS (differential GPS), which is an example of DGNSS (differential GNSS), is used as the satellite positioning system. It is also possible to use other satellite positioning systems such as RTK (real-time kinematic) and SBAS (geostationary satellite-based augmentation system), without being limited to DGPS.

[0023] [Driving operation section] Next, the driving operation unit 30 will be described. As shown in Figs. 2 and 3, in addition to a steering handle 32 and a main speed change lever 33, various operating tools and a display device 34 are arranged on the operation panel 31. The steering handle 32 is provided in front of the driver's seat 14. A speed change pedal and a brake pedal (not shown) are provided below the operation panel 31. The speed change pedal is an operating tool for changing the vehicle speed of the rice transplanter 1. The brake pedal is an operating tool for braking the rice transplanter 1. In general, the speed change pedal is arranged below and to the right of the operation panel 31, and the brake pedal is arranged to the left of the speed change pedal.

[0024] The rice transplanter 1 includes an operating member 50 for performing operations related to automatic travel, and an arm member 35 for supporting the operating member 50. The operating member 50 is fixed to the support frames 16, 16 of the spare seedling table 15 via the arm member 35. This allows the operating member 50 to be firmly supported. The operating member 50 is disposed on the outer side in the machine width direction than the operation panel 31. The operating member 50 is disposed on the right side of the driving operation unit 12, but may be disposed on the left side. However, by disposing the operating member 50 on the same side as the speed change pedal (generally on the right side), it becomes easier to press the AUTO button 51 of the operating member 50, which will be described later, at the same timing as accelerating when starting straight-line work, improving operability.

[0025] The arm member 35 includes a stay-shaped upper arm portion 35a fixed to the support frame 16, a forearm portion 35c that rotates horizontally with respect to the upper arm portion 35a at a hinge 35b as a fulcrum, and a holder 35e that rotates horizontally with respect to the forearm portion 35c at a hinge 35d as a fulcrum. The operating member 50 is attached to the holder 35e. Elbow portions 35f, 35f that are bent in the vertical direction are formed at both ends of the forearm portion 35c. The elbow portion 35f may be configured to be able to rotate vertically via a hinge. By rotating the forearm portion 35c horizontally to approach the upper arm portion 35a, the arm member 35 can be stored compactly and the passage width in front of the spare seedling tray 15 can be secured. The operating member 50 held by the holder 35e can be moved within the movable range of the arm member 35.

[0026] The operating member 50 supported by the arm member 35 can preferably move within a range from the front end to the rear end of the steering handle 32 in a plan view (i.e., within a range between the imaginary straight lines L1 and L2 shown in FIG. 2). In the vertical direction, the operating member 50 can preferably move within a height range from the upper end to the lower end of the steering handle 32. In addition, from the viewpoint of preventing deterioration of visibility, it is preferable that the operating member 50 cannot move rearward from the rear end of the steering handle 32 in a plan view (i.e., rearward from the imaginary straight line L2). The operating member 50 is disposed forward of the imaginary straight line L3 connecting the rear side support frame 16 and the outer end of the backrest of the driver's seat 14. This prevents the operating member 50 from getting in the way when performing seedling transplanting work.

[0027] In this embodiment, as shown in Fig. 4, the operation member 50 has an AUTO button 51 which is an indicator for instructing the start of automatic driving, and an indicator lamp 52 which is an indicator constituting a notification unit 66 described later. Furthermore, the operation member 50 has an A button 53 which is an indicator for performing a registration operation of a point A, and a B button 54 which is an indicator for performing a registration operation of a point B. The AUTO button 51 is disposed in the center of the operation surface 50f of the operation member 50, and the indicator lamp 52 is disposed in the upper left thereof. The A button 53 and the B button 54 are disposed side by side on the left and right below the AUTO button 51.

[0028] The AUTO button 51 is operated to start and stop automatic driving. The AUTO button 51 is operated more frequently than the A button 53 and the B button 54, so it is formed larger than the A button 53 and the B button 54 when viewed from the front to make it easier to press. The AUTO button 51 also protrudes more than the A button 53 and the B button 54. The A button 53 and the B button 54 are buttons of the same shape, but are arranged symmetrically. A ring-shaped light-emitting unit 55 is provided around the AUTO button 51. As described later, the light-emitting unit 55 has the function of notifying the operator of various states related to automatic driving by its light color and lighting pattern.

[0029] The indicator lamp 52 indicates the positioning accuracy corresponding to the positioning state of the positioning unit 43 in stages by displaying light, more specifically, by using multiple types (two types in this embodiment) of light colors and lighting patterns. This positioning state serves as a criterion for determining whether automatic driving can be started or continued. Since the indicator lamp 52 is provided on the operation member 50 equipped with the AUTO button 51, the operator can instruct the start of automatic driving while checking whether automatic driving is possible. In addition, since the operation member 50 is provided independently from the operation panel 31, it is convenient that there is no need to modify the operation panel when additionally installing an automatic driving system on an existing rice transplanter.

[0030] [Autonomous Driving Configuration] 5 is a block diagram showing the main components related to automatic driving. The positioning unit 43 includes a positioning antenna 43a, a position measuring device 43b, and an inertial measurement device (IMU) 43c. The positioning antenna 43a receives signals from positioning satellites (GPS satellites in this embodiment) that constitute a satellite positioning system. The positioning signals received by the positioning antenna 43a are input to the position measuring device 43b. The position measuring device 43b processes the input positioning signals to measure the vehicle position. The inertial measurement device 43c identifies the attitude (roll angle, pitch angle, yaw angle) of the traveling body 2.

[0031] The rice transplanter 1 is equipped with a control unit 60 for controlling the operation of the traveling body 2 (forward, backward, stopping, turning, etc.) and the operation of the planting unit 20, which is the working unit (lifting, lowering, driving, stopping, etc.). The control unit 60 is configured with a CPU, ROM, RAM, I / O, etc., which are not shown. The CPU can read and execute various programs from the ROM. The ROM stores operation programs, application programs, and various data. Through cooperation between such hardware and software, the control unit 60 can operate as a memory unit 61, a processing unit 62, an automatic traveling control unit 63, etc.

[0032] The memory unit 61 stores various information required for automatic travel of the rice transplanter 1. Such information includes, for example, the horizontal distance from the positioning antenna 43a to the seedling planting mechanism 25 and the positions of points A and B registered and set by the operator. The processing unit 62 performs various processes required for automatic travel of the rice transplanter 1. Such processes include determining the positioning accuracy based on the positioning state of the positioning unit 43 and determining whether automatic travel is permitted based on the determination result. The automatic travel control unit 63 performs control related to automatic travel.

[0033] The automatic travel control unit 63 controls the automatic travel actuator 64 so that the rice transplanter 1 travels along the travel route based on the information of the vehicle's position measured by the positioning unit 43. The automatic travel actuator 64 refers to various actuators that are operated during automatic travel, and includes an actuator that steers the steering wheel 32, an actuator that changes the speed of the transmission case 8, an actuator (lifting cylinder 22) that raises and lowers the planting unit 20, and the like. The automatic travel control unit 63 controls the operation of the rice transplanter 1 based on a signal from an automatic travel sensor 65 provided in the rice transplanter 1.

[0034] The control unit 60 judges the positioning accuracy based on the positioning state of the positioning unit 43, and permits automatic driving when the positioning accuracy is equal to or higher than a predetermined accuracy. The positioning state of the positioning unit 43 changes dynamically due to the number of valid GNSS satellites whose signal strength is equal to or higher than a predetermined level, HDOP (a dilution rate of accuracy for position determination in a horizontal plane), GPS age, and the like. FIG. 6 shows the judgment conditions for the positioning accuracy based on the positioning state, and the types of automatic driving and notification corresponding to the judged positioning accuracy. In this judgment condition, if the DGPS is in an enabled state (DGPS state), the positioning accuracy is judged to be level 5, level 4, or level 3. Also, if the DGPS is in an disabled state (SGPS state) and the state is SGPS (single GPS as single GNSS, independent positioning), the positioning accuracy is judged to be level 2 or level 1.

[0035] Level 5 corresponds to a positioning state that is equal to or higher than the average value of a predetermined evaluation condition. For example, the evaluation condition is a condition that a certain degree of accuracy is guaranteed by the manufacturer of the positioning unit 43. Level 4 corresponds to a positioning state (first positioning state) that does not satisfy the condition of level 5 but falls within the range of the evaluation condition. Level 3 corresponds to a positioning state (second positioning state) that is a DGPS state and does not satisfy the conditions of levels 4 and 5. In all of levels 5 to 3, the start of automatic driving is permitted, and the continuation of automatic driving is also permitted (i.e., automatic driving is not interrupted). In this embodiment, the positioning accuracy is determined in five levels, but is not limited to this. For example, level 5 may be integrated into level 4 to make four levels.

[0036] Level 2 corresponds to a state (third positioning state) in which the duration of the SGPS state is within X seconds after transition from the DGPS state to the SGPS state. The control unit 60 is configured to be able to set any time that is X seconds. Level 1 corresponds to a state in which the SGPS state continues for more than X seconds after transition from the DGPS state to the SGPS state, or a state other than levels 2 to 5. In level 2, the start of automatic driving is prohibited, but the continuation of automatic driving is permitted. The reason why the continuation of automatic driving is permitted in level 2 is that stable automatic driving can be maintained even if the automatic driving is continued when the DGPS state is restored in a relatively short time even if the positioning accuracy is reduced. In level 1, both the start and continuation of automatic driving are prohibited, and automatic driving is not executed even if the AUTO button 51 is pressed.

[0037] As shown in Figures 5 and 6, the rice transplanter 1 is equipped with an alarm unit 66, which, in response to the control of the control unit 60, executes a first alarm indicating that the positioning accuracy is level 4, which corresponds to a first accuracy equal to or higher than a predetermined accuracy, and a second alarm indicating that the positioning accuracy is level 3, which corresponds to a second accuracy equal to or higher than a predetermined accuracy. Furthermore, in response to the control of the control unit 60, the alarm unit 66 executes a third alarm indicating that the positioning accuracy is level 2, which corresponds to a third accuracy, a fourth alarm indicating that the positioning accuracy is level 1, which corresponds to a fourth accuracy, and a alarm indicating that the positioning accuracy is level 5. The third accuracy and the fourth accuracy are lower than the first accuracy and the second accuracy, respectively. The fourth accuracy is lower than the third accuracy. The notification unit 66 is configured with an indication lamp 52 provided on the operation member 50.

[0038] The indicator lamp 52 issues a notification by a light color and a lighting pattern. The first notification is a "continuous green flash" in which the indicator lamp 52 lights up green and flashes at a predetermined cycle (for example, 1 second cycle). The second notification is a "twice green flash" in which the indicator lamp 52 lights up green and flashes twice in a predetermined unit time (for example, 1 second), then goes off for the predetermined unit time, and these are repeated alternately. The third notification is a "red flash" in which the indicator lamp 52 lights up red and flashes at a predetermined cycle (for example, 1 second cycle). The fourth notification is a "red light" in which the indicator lamp 52 continues to light up red. The notification indicating level 5 is a "green light" in which the indicator lamp 52 continues to light up green. The notification modes executed by the notification unit 66 are not limited to these, and for example, the light color of the indicator lamp 52 may be yellow.

[0039] The rice transplanter 1 of this embodiment includes an alarm device 67 that emits an alarm sound according to the control by the control unit 60. When the control unit 60 causes the indicator lamp 52 to execute the third notification, the control unit 60 controls the alarm device 67 to intermittently sound an alarm sound at a predetermined cycle (for example, every 1 second). Also, when the control unit 60 causes the indicator lamp 52 to execute the fourth notification, the control unit 60 controls the alarm device 67 to continuously sound an alarm sound. By using light and sound to notify the operator when the positioning state is the SGPS state, it is possible to call for caution. Instead of or in addition to the rhythm of the alarm sound, the volume, pitch, tone, etc. of the alarm sound may be changed. The alarm device 67 may be provided in the operation member 50.

[0040] As shown in FIG. 7A, while the positioning state is the second positioning state, the control unit 60 determines that the positioning accuracy is level 3, and controls the indicator lamp 52 to execute the second notification "two green flashes". This notifies the operator that the current positioning state is in the DGPS state and that automatic driving can be started and continued. Also, when the positioning accuracy is changed from the second positioning state to the first positioning state, the control unit 60 transitions the positioning accuracy from level 3 to level 4 at time T1, and controls the indicator lamp 52 to immediately execute the first notification "continuous green flash". Similarly, when the positioning accuracy is changed from the first positioning state to the second positioning state, the control unit 60 transitions the positioning accuracy from level 4 to level 3 at time T2, and causes the indicator lamp 52 to execute "two green flashes". This makes it possible to notify the operator of the change in the positioning state.

[0041] Since the positioning state of the positioning unit 43 changes fluidly depending on the situation, if the notification is changed frequently in response to the change, the operator may misunderstand that the current positioning state is unstable or may misread the state. For example, when the positioning state of the positioning unit 43 is changed from the second positioning state to the first positioning state and then immediately changed to the second positioning state, if the notification changes from "green flashing twice" to "green flashing continuously" and then immediately thereafter to "green flashing twice," this misunderstanding is likely to be given. In particular, the "green flashing continuously" and the "green flashing twice" are the same light color and are simply different in their lighting patterns (flashing rhythm), so this is a major concern.

[0042] Therefore, as shown in FIG. 7B, when the condition for the positioning accuracy to transition from the first accuracy to the second accuracy (level 3) is satisfied within a first predetermined time, specifically within Ya seconds from time T1, after the rice transplanter 1 executes "continuous green flashing" in response to the transition to the first accuracy (level 4), the rice transplanter 1 continues to execute "continuous green flashing" until Yb seconds corresponding to the second predetermined time have elapsed, and after the Yb seconds have elapsed, ends "continuous green flashing" and executes "two green flashes" (second notification). In this case, a time lag TL occurs between time T3 when the positioning state is changed and time T4 when the notification is changed. However, since both the first accuracy and the second accuracy are positioning accuracy levels equal to or higher than the predetermined accuracy at which automatic driving is permitted, there is no problem in continuing automatic driving as long as these continue, even if the positioning state is changed continuously.

[0043] In this embodiment, level 4 is the first accuracy and level 3 is the second accuracy, but the first accuracy and second accuracy may be any positioning accuracy at which autonomous driving is permitted. For example, levels 3 and 4 may be regarded as the first and second accuracy, respectively, or levels 5 and 4 may be regarded as the first and second accuracy, respectively. Even in such cases, it is possible to execute notification in the manner shown in FIG. 7B.

[0044] In the example shown in FIG. 7B, in a situation where the positioning state is changed from the first positioning state to the second positioning state within Ya seconds after the positioning state is changed from the second positioning state to the first positioning state, a level transition (a transition of the positioning accuracy) is not performed until Yb seconds have elapsed, and the level transition is performed after Yb seconds have elapsed. This is because the control unit 60 is configured not to judge the positioning accuracy within Yb seconds from the time T1 at which the level transition is performed, except for the judgment for level 1. In other words, after the level transition is performed, a transition prohibition time (Yb seconds, which is a second predetermined time) is provided to prohibit a transition to a positioning accuracy other than level 1. In this embodiment, Yb seconds are calculated from the same time T1 as Ya seconds.

[0045] In this manner, in this embodiment, when the positioning state fluctuates in small increments, the positioning accuracy is prohibited from immediately transitioning, and the notification is not immediately changed accordingly. However, the present invention is not limited to this, and may be configured to immediately transition the positioning accuracy at the time T3 when the positioning state is changed continuously within Ya seconds, as in the modified example of FIG. 7C. Alternatively, as in the modified example of FIG. 7D, a time (Z seconds) different from the second predetermined time (Yb seconds) that is the notification change criterion may be set, and the positioning accuracy may be transitioned at the time T5 when the time has elapsed. In either case, the control unit 60 controls the display lamp 52 to end the "continuous green flash" and execute the "two green flashes" after the second predetermined time (transition prohibition time) has elapsed. However, in light of the viewpoint of matching the positioning accuracy and the notification type, it is more preferable to control in the manner of FIG. 7B than in the manner of FIG. 7C or FIG. 7D.

[0046] The lengths of the first and second predetermined times are not particularly limited. The control unit 60 is configured to be able to set any time to Ya and Yb seconds. From the viewpoint of increasing the visibility of the indicator lamp 52, it is preferable that Yb seconds is the same as or longer than the blinking cycle of the indicator lamp 52. It is also preferable that Yb seconds is the same as or shorter than the above-mentioned X seconds (i.e., X≧Yb). As a result, in the case of controlling in the manner of FIG. 7C, even if the positioning state is changed from the second positioning state to the third positioning state within Ya seconds from the time point T1 at which the level transition is performed, the positioning accuracy will not transition to level 1 within Yb seconds (i.e., X seconds will not elapse). Therefore, it is possible to prevent the indicator lamp 52 from lighting up green in a situation in which automatic driving is prohibited. X seconds is set to, for example, 10 seconds, and Yb seconds is set to, for example, 2 seconds.

[0047] In this embodiment, the second predetermined time (Yb seconds) is set to the same time as the first predetermined time (Ya seconds), but is not limited to this and may be set to different times. Therefore, as illustrated in FIG. 7E, it is possible to set Yb seconds to a time longer than Ya seconds. In this case, the first notification "continuous green flashing" does not end even after Ya seconds have passed, but continues until Yb seconds have passed, and continues for an additional period of time compared to the case of FIG. 7B.

[0048] In this embodiment, after the first notification "continuous green flash" ends after the second predetermined time (Yb seconds) has elapsed, the second notification "two green flashes" is executed without any interval, but this is not limited to this and the second notification may be executed with an interval. Therefore, as illustrated in FIG. 7F, after the "continuous green flash" ends after Yb seconds, it is possible to execute the "two green flashes" with a blank period BP in which no notification is executed. The blank period BP is set to, for example, a few seconds or less.

[0049] When the positioning accuracy is the third accuracy (level 2), the control unit 60 prohibits the start of automatic traveling while permitting the continuation of automatic traveling. The notification unit 66 executes "red flashing" (third notification) indicating that the positioning accuracy is the third accuracy according to the control by the control unit 60. As shown in FIG. 8, the rice transplanter 1 is configured to continue executing "green flashing twice" until Yd seconds corresponding to the fourth predetermined time have elapsed when the condition for the positioning accuracy to transition from the second accuracy to the third accuracy is satisfied within a third predetermined time after executing "green flashing twice" (second notification) in response to the transition to the second accuracy, specifically within Yc seconds from time T6, that is, when the positioning state is changed from the second positioning state to the third positioning state. The rice transplanter 1 is configured to continue executing "green flashing twice" until Yd seconds corresponding to the fourth predetermined time have elapsed, and to end "green flashing twice" and execute "red flashing" after the passage of Yd seconds. The timing of the time T7 when the positioning state is changed and the time T8 when the notification is changed are different. In this way, the third accuracy is handled in the same way as the high accuracy positioning accuracy (first and second accuracy). The matters already explained about the first predetermined time (Ya seconds) and the second predetermined time (Yb seconds) can also be applied to the third predetermined time (Yc seconds) and the fourth predetermined time (Yd seconds), respectively.

[0050] The control unit 60 prohibits the start and continuation of automatic driving when the positioning accuracy is the fourth accuracy (Level 1). The notification unit 66 executes "red light" (fourth notification) indicating that the positioning accuracy is the fourth accuracy according to the control by the control unit 60. The rice transplanter 1 is configured to immediately execute "red light" when the condition for the positioning accuracy to transition to the fourth accuracy is met, that is, when the positioning accuracy continues for more than X seconds after transition to the SGPS state. Since level 1 involves an emergency stop, the fourth notification is executed immediately. This allows the operator to be notified without delay that the cause of the end of automatic driving is the deterioration of the positioning state.

[0051] [Function of the light-emitting part of the operation part] Next, the function of the light-emitting unit 55 provided around the AUTO button 51 will be described. In response to the control of the control unit 60, the light-emitting unit 55 informs the operator of various situations related to automatic driving by its light color and lighting pattern. The operation member 50 incorporates a plurality of light-emitting elements 55L arranged along the light-emitting unit 55 (see FIG. 4). In this embodiment, a total of eight light-emitting elements 55L are used, with two in each quadrant, but this is not limited to this. The light-emitting elements 55L are, for example, LEDs.

[0052] As shown in FIG. 9, the light color and lighting pattern of the light emitting unit 55 can be changed according to various situations such as during automatic driving, during preparation to start automatic driving, preparation to start automatic driving is complete, and when an abnormality occurs. FIG. 9(A) is a display during automatic driving, in which the entire light emitting unit 55 lights up in green as the first light color and blinks at a fixed cycle. FIG. 9(B) is a display during preparation to start automatic driving, in which the entire light emitting unit 55 lights up in green and blinks with a different number of blinks and tempo from FIG. 9(A). Depending on the number of blinks and the pattern, an operator can be instructed to perform an operation such as registering point A. FIGS. 9(C) to (H) are also displays during preparation to start automatic driving, in which the light emitting unit 55 lights up in green in all cases.

[0053] Before or after the engine is started, a part of the light-emitting unit 55 is turned on and the lighting position is rotated as shown in FIG. 9(C). When the vehicle is tilted left or right, the left and right sides of the light-emitting unit 55 are flashed as shown in FIG. 9(D) to inform the operator. Similarly, when the vehicle is tilted forward or backward, the top and bottom of the light-emitting unit 55 are flashed as shown in FIG. 9(E). When the forward or backward direction of the vehicle is tilted with respect to the target route and there is a deviation to the right (the steering handle 32 needs to be turned to the right), the upper right side of the light-emitting unit 55 is lit as shown in FIG. 9(F) to provide guidance. Similarly, when reverse travel is required, the lower part of the light-emitting unit 55 is lit as shown in FIG. 9(G), and when there is no deviation, the upper part of the light-emitting unit 55 is lit as shown in FIG. 9(H), to provide guidance.

[0054] FIG. 9(I) shows the display indicating that preparations for starting automatic driving are complete, and the entire light-emitting section 55 lights up in green. FIG. 9(J) shows a display when an abnormality occurs, in which the light-emitting unit 55 lights up in red, which is the second light color. In the illustrated example, the left and right sides of the light-emitting unit 55 are lit up, but the location where the light is lit can be changed depending on where the abnormality occurs. For example, it is possible to light up the upper right side of the light-emitting unit 55 in red when the positioning antenna 43a has failed, and light up the lower left side of the light-emitting unit 55 in red when the power steering has failed.

[0055] [Control structure for autonomous driving] Next, an example of a control structure for automatic traveling will be described. As shown in FIG. 10, the automatic traveling control unit 63 (automatic traveling controller) is connected to other control controllers, and obtains information from them to perform control necessary for automatic traveling. The other control controllers include an engine control controller 71 that controls the operation of the engine 7, a working unit control controller 72 that controls the operation of the planting unit 20, a traveling control controller 73 that controls the operation of the traveling unit 10, and a display control controller 74 that controls the display device 34. In addition, the control necessary for automatic traveling includes control of an automatic traveling antenna 75 (positioning unit 43), an automatic traveling HMI (human machine interface) 76, and an automatic traveling actuator 64.

[0056] The automatic driving control unit 63 can be configured to stop automatic driving based on error information (fault information) acquired from another controller when an abnormality is detected in any part of the rice transplanter 1 during automatic driving. In this case, the automatic driving control unit 63 must determine whether the acquired error information affects automatic driving or not, and must determine whether to stop automatic driving or not based on the result. Therefore, the automatic driving control unit 63 requires high processing power, and a controller with low processing power cannot be applied, which makes the construction of the control structure complicated.

[0057] On the other hand, as shown in FIG. 11, the automatic driving control unit 63 may be structurally separated from the other control controllers. In this case, the automatic driving control unit 63 can individually execute necessary control independent of error information held by the other control controllers. Therefore, even if an abnormality that does not affect automatic driving, such as a failure of the display device 34, occurs, control can be performed without interfering with automatic driving. Such an automatic driving control unit 63 does not require high processing power, and a controller with low processing power can be applied, making it easier to build a control structure. In FIG. 11, the automatic driving control unit 63 is not connected to any of the other control controllers, but it is also possible to connect it to one of them and not to the remaining three, for example.

[0058] The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0059] 1. Rice transplanter (an example of a work vehicle) 14 Driver's seat 32 Steering handle 35 Arm parts 43 Positioning unit (positioning section) 50 Operation member 51 AUTO button (pointer) 52 Indicator lamp (indicator) 60 Control section 66 Notification Department

Claims

1. A work vehicle that performs automatic driving while identifying its own position using a satellite positioning system, the operation member is provided with a first indicator for registering a start point of a reference route for automatic driving, a second indicator for registering an end point of the reference route, and a third indicator which is operated when starting and stopping automatic driving, the first indicator and the second indicator are arranged side by side on the left and right, and a positioning accuracy based on a positioning signal from a satellite positioning system is displayed; When the positioning accuracy becomes lower than a predetermined accuracy during automatic driving, automatic driving is not continued. A work vehicle characterized by:

2. The work vehicle according to claim 1 , wherein the positioning accuracy is displayed in stages on the operation member using a plurality of notification patterns.

3. A ring-shaped light-emitting unit is provided around the third pointing tool, The light emitting unit notifies the driver of the situation regarding automatic driving by the light color and the lighting pattern, The light emitting portion of the operation member indicates whether or not automatic driving is being performed.

3. A work vehicle according to claim 1 or 2.

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