Work vehicle

Abstract

In the present invention, on the basis of the results of measuring a power meter (202) during work performed in the course of traveling in manual driving mode, a control unit (300) controls the power consumption and the rate of change in power of an electric motor (4, M0) during an automatic driving mode, and as a result thereof, work can be performed by automatic driving such that the content of the work is the same as the content of work performed by manual driving that reflects the actual field conditions, and in comparison to conventional technologies in which a travel route is registered in advance, the occurrence of running out of power during automatic driving can be suppressed.

Description

Work vehicles

[0001] The present invention relates to a work vehicle in which a traveling device and a work machine are electrically driven.

[0002] A technology is known for an autonomously driven work vehicle that automatically creates a predetermined driving route based on the battery charge so that the vehicle moves to a predetermined charging station (Patent Document 1).

[0003] JP 2016-27456 A

[0004] In the technology described in Patent Document 1, the driving route and the locations of charging stations are registered in advance. Therefore, when traveling along a set driving route, it is not possible to precisely respond to the condition of the field as in the case of manned driving, and it is difficult to respond to load fluctuations depending on the field conditions, such as localized soft ground. Therefore, there is a concern that the battery may run out of power earlier than expected, which is known as a lack of power.

[0005] The present invention has as its technical objective the prevention of power shortages occurring during automatic driving, compared to conventional technologies in which driving routes are registered in advance.

[0006] The above-mentioned problems of the present invention are solved by the following means for solving the problems. The invention described in claim 1 provides a vehicle comprising: a vehicle body (1a), a work implement (18, 7, 252) supported by the vehicle body (1a) and operating during work in a field, an electric motor (4, M0) that drives a traveling device (2, 3) of the vehicle body (1a) and the work implement (18, 7, 252), a power meter (202) that measures the power consumption value or the rate of change of power in the electric motor (4, M0), and a power meter (202) that measures the power consumption value or the rate of change of power in the work implement (18, 7, 252) while automatically traveling the vehicle body (1a) along a predetermined traveling route (401). and a control unit (300) for switching between an automatic driving mode in which the work implement (18, 7, 252) is controlled based on work information from a work vehicle (18, 7, 252) and a manual driving mode in which the work implement (18, 7, 252) is controlled while the vehicle body (1a) is traveling in accordance with the operation of a worker, and the control unit (300) controls the power consumption value or the rate of change in power of the electric motor (4, M0) in the automatic driving mode based on the measurement results of the power meter (202) when work is performed while traveling in the manual driving mode.

[0007] According to the present invention, the control unit (300) controls the power consumption value and the rate of change in power of the electric motor (4, M0) in the automatic driving mode based on the measurement results of the power meter (202) when working while driving in the manual driving mode, so that work can be performed in the automatic driving mode with the work content during manual driving that corresponds to the actual situation in the field, and it is possible to reduce the occurrence of power shortages during the automatic driving compared to the conventional technology in which the driving route is registered in advance.

[0008] Furthermore, by automatically driving at the driving speed included in the driving information and controlling the storage section (7) based on the grass discharge position (408, 409) included in the work machine information, work can be performed automatically with the same work content as when manually driven, according to the actual conditions of the field.

[0009] Furthermore, when at least one of the power consumption value and the rate of change reaches a threshold, the traveling speed is reduced so that the threshold is not reached, thereby preventing the load on the work vehicle from becoming excessive.

[0010] Furthermore, when the remaining charge of the battery (5a) falls below a predetermined value, the work can be interrupted and the battery (5a) can be automatically charged. After charging is complete, the vehicle body (1a) is automatically driven to the position where the work was interrupted by aligning its direction of travel with the direction of travel when the work was interrupted, allowing the work to be smoothly resumed.

[0011] In addition, the power receiver (502) can be charged wirelessly, and work can be performed while charging within the range where the power receiver (502) can receive power from the optical wireless power supply device (503), improving work efficiency.

[0012] FIG. 1 is an explanatory diagram of a tractor as an example of a work vehicle according to an embodiment. FIG. 2 is a functional block diagram of a control unit according to an embodiment. FIG. 3 is an explanatory diagram of an example of a travel route according to an embodiment. FIG. 4 is an explanatory diagram of an example of charging during automatic travel. FIG. 5 is an explanatory diagram of a work vehicle during charging. FIG. 6 is an explanatory diagram of a flowchart of automatic travel mode processing for a tractor according to an embodiment. FIG. 7 is an explanatory diagram of a flowchart of automatic travel mode processing for a tractor according to an embodiment, and is a continuation of FIG. 6. FIG. 8 is an explanatory diagram of a work vehicle according to another embodiment.

[0013] FIG. 1 is an explanatory diagram of a tractor as an example of a work vehicle according to an embodiment of the present invention. In FIG. 1, the tractor 1, which is an example of a work vehicle according to the present invention, is equipped with front wheels 2, 2 and rear wheels 3, 3 at the front and rear of a traveling body (an example of a vehicle main body) 1a. A traveling motor 4, which is an example of a first electric motor, is mounted below a driver's seat 8 at the rear of the traveling body 1a. The rotational power of the traveling motor 4 is appropriately reduced by a speed change device in a transmission case (not shown) and transmitted to the front wheels 2, 2 and rear wheels 3, 3. In this specification, the left and right sides of the tractor 1 as viewed in its forward direction are referred to as the left and right sides, respectively, and the forward direction is referred to as the front side and the reverse direction is referred to as the rear side.

[0014] A container 7, which is an example of a work machine and an example of a storage section, is supported at the rear of the tractor 1. Cut grass is stored in the container 7. Note that, instead of the container 7, a work machine such as a tiller that tills the ground (field) behind the tractor 1 can be attached to the rear of the tractor 1. A grass collector (not shown) is disposed at the front of the container 7. Power is transmitted to the grass collector via a PTO shaft (rear PTO shaft) (not shown). The grass collector sends (transports) the cut grass into the container 7. Drive is transmitted to the PTO shaft in this embodiment from a PTO motor M0, which is an example of a second electric motor, via a first clutch or the like.

[0015] In the tractor 1 of the embodiment, a lawnmower 18, which is an example of a work machine and an example of a mowing device, is supported between the front wheels 2 and the rear wheels 3. The lawnmower 18 performs mowing work by mowing grass (lawn) in a field. Power is transmitted to the lawnmower 18 via a second PTO shaft (mid-PTO shaft) and a second clutch (not shown). The second PTO shaft is driven by a PTO motor M0, but a separate motor dedicated to the second PTO shaft can also be installed. The lawnmower 18 of the embodiment can be raised and lowered and its height adjusted using a lifting cylinder (not shown) to prevent contact with the road surface when traveling on the road and to adjust its height relative to the field.

[0016] A driver's seat (operating seat) 8 is disposed at the top of the traveling vehicle body 1a, and a steering wheel 10 is disposed in front of the driver's seat 8. Also disposed in front of the driver's seat 8 are a display panel (meter panel) including a speedometer (not shown), various operation switches (not shown), and the like. Disposed below and in front of the driver's seat 8 are driving operation devices such as a brake pedal 12 and an accelerator pedal 13 having a forward pedal and a reverse pedal.

[0017] In Figure 1, lift arms 15, 15 are pivotally mounted to the rear of the traveling vehicle body 1a. Lift rods (not shown) are interposed and connected between the lift arms 15, 15 and lower links 16, 16. A container 7 is attached to the lift arms 15 and the lower links 16, but instead of the container 7, a work machine such as a tiller can be attached.

[0018] The lift arms 15 are driven by hydraulic cylinders (not shown). When the hydraulic pressure in the hydraulic cylinders increases and the lift arms 15, 15 are rotated upward, the working machine (container 7) is raised via the lift rod, lower link 16, etc. When the hydraulic oil is discharged and the hydraulic pressure decreases, the lift arms 15, 15 are lowered. Therefore, when the grass collected in the container 7 is to be discharged, the lift arms 15 are raised, the rear end of the container 7 is turned downward, and the grass is discharged from the rear end. Note that working machines that can be attached to the rear of the traveling body 1a include rotary tillers for agricultural work, plows, seed sowing machines, seedling transplanters, fertilizer spreaders, chemical sprayers, and other working machines.

[0019] (Explanation of the control unit of the tractor 1) Figure 2 is a functional block diagram of the control unit of the embodiment. The tractor 1 of the embodiment has a control unit 300 that controls each function. The control unit 300 has an input / output interface I / O that performs input and output of signals with the outside. The control unit 300 also has a read-only memory (ROM) that stores programs and information for performing necessary processing. The control unit 300 also has a random access memory (RAM) for temporarily storing necessary data. The control unit 300 also has a central processing unit (CPU) that performs processing according to the programs stored in the ROM or the like. Therefore, the control unit 300 of the embodiment is configured with a small information processing device, a so-called microcomputer. Therefore, the control unit 300 can realize various functions by executing programs stored in the ROM or the like.

[0020] The control unit 300 receives signals from a display panel (not shown), which is an example of an input unit and an example of a display unit, and is configured as a touch panel, as well as from signal input elements such as a positioning device 201, a power meter 202, an automatic driving switch 203, a battery remaining capacity measuring means 204, and various other sensors not shown.

[0021] The positioning device 201 has a GNSS (Global Navigation Satellite System) receiver 201a and an IMU (Inertial Measurement Unit, an example of an inclination measurement component) 201b. The GNSS receiver 201a receives positioning signals from artificial satellites and can measure the current position of the tractor 1. The IMU 201b measures acceleration and angular velocity and can measure the direction (direction of travel) and attitude (left-right tilt and front-back tilt) of the tractor 1. Therefore, by correcting the measurement results of the GNSS receiver 201a with the IMU 201b, the current position can be measured with higher accuracy than when the current position is measured using only the GNSS system.

[0022] The power meter 202 measures the power supplied from the battery 5a (see FIG. 1) inside the hood 5 to the traction motor 4 and the PTO motor M0. As an example, an ammeter can be used as the power meter 202, and an ammeter connected to the output terminal of the battery 5a can be used. In the embodiment, the ammeters are individually arranged according to the power supply system so as to individually measure the power supplied to each of the traction motor 4 and the PTO motor M0, but this is not limited to this. It is also possible to adopt a mode in which the sum of the output currents is measured. Furthermore, although the embodiment measures current, it is also possible to measure voltage, or any parameter linked to power.

[0023] An input operation to start automatic driving is performed through the automatic driving switch 203. The remaining battery capacity measuring means 204 measures the remaining capacity (remaining amount of power) of the battery 5a.

[0024] The control unit 300 sends control signals to the power supply circuit E, the travel motor 4, the PTO motor M0, the hydraulic cylinder S1, the lift cylinder S2, the first clutch CL1, the second clutch CL2, and the like, which are examples of controlled elements, to control the running / stopping and running speed of the tractor 1, the operation / stopping and operation speed of the lawnmower 18, the raising and lowering (raising to the discharge position and lowering to the storage position) of the container 7 attached to the lift arm 15, and the operation / stopping of the grass collector (an example of a work machine) 252. The control unit 300 also outputs control signals to a display monitor, which is an example of a display unit, and is capable of displaying work information, work status, the vehicle's position, and the like.

[0025] The tractor 1 of this embodiment is equipped with a total of two electric motors 4, M0, including the travel motor 4 and the PTO motor M0. The number of electric motors is not limited to two, and it is possible to have a total of three (or more) motors by providing a PTO motor for each of the lawn mower 18 and the grass collector 252, or it is possible to use the power of the travel motor 4 to drive both the lawn mower 18 and the grass collector 252, thereby using only one travel motor 4 as the electric motor.

[0026] The positioning means 301 measures the current position of the tractor 1 based on the measurement results of the positioning device 201. The work information storage means 302 has a travel information storage means 302a and a work implement information storage means 302b, and stores information about work in the field.

[0027] FIG. 3 is an explanatory diagram of an example of a travel route according to an embodiment. The travel information storage means 302a stores information related to the travel of the tractor 1 when working in a field. In FIG. 3, in this embodiment, examples of travel information include information on a travel route 401 and information on travel speed. The information on the travel route 401 also includes a work start position 402, a work end position 403, a turning position 404, and, if there is a switch between forward and reverse (a change of direction), the change of direction. The travel speed information is not limited to a fixed set speed, and the travel speed is stored for each section of a predetermined length along the travel route in the field.

[0028] The work machine information storage means 302b stores information related to the operation and stoppage of work machines (the lawn mower 18 and the container 7) when working in the field. In this embodiment, examples of work machine information stored include the coordinates in the field of the raised positions 404a, 406 to which the lawn mower 18 is raised and the lowered positions 404b, 407 to which the lawn mower 18 is lowered, the coordinates of the discharge start position 408 and discharge end position 409 to which grass is discharged from the container 7, and the operating speeds of the lawn mower 18 and the grass collector 252. The operating speeds of the lawn mower 18 and the grass collector 252 are preferably stored for each section of a predetermined length, similar to the traveling speed.

[0029] In this embodiment, the travel route, travel speed, raised and lowered positions of the lawnmower 18, etc. are measured and stored based on the travel route and other information from previous manual travels of the tractor 1. It is also possible to set the turning start position 404a as the raised position and the turning end position 404b as the lowered position. Additionally, if the lawnmower 18 is manually raised or lowered along the travel route 401 due to localized unevenness in the field, the raised position 406 and lowered position 407 are stored as information. Additionally, in this embodiment, the work information storage means 302 also stores a charging position 411 where a charging device is located as an example of travel information.

[0030] The travel control means 303 controls the travel motor 4 to control the travel (acceleration / deceleration, steering, braking) of the tractor 1. During manual travel (when working in manual travel mode), the travel control means 303 controls the travel motor 4 in accordance with input to the accelerator pedal 13, brake pedal 12, steering wheel 10, a speed change lever (not shown), etc. to control the travel (acceleration / deceleration, steering, braking) of the tractor 1. During automatic travel, the travel control means 303 controls the travel motor 4, accelerator pedal 13, brake pedal 12, steering wheel 10, a speed change lever (not shown), etc. based on the measurement results of the positioning means 301 and the travel information and work machine information stored in the work information storage means 302 to control the automatic travel (acceleration / deceleration, steering, braking) of the tractor 1.

[0031] The work machine control means 304 controls the PTO motor M0, hydraulic cylinder S1, lift cylinder S2, and clutches CL1 and CL2 to control the operation of the lawn mower 18, container 7, and grass collector 252. During manual travel, the work machine control means 304 in this embodiment controls the PTO motor M0, etc. in accordance with inputs to work machine switches and work speed setting switches (not shown), to control the operation of the lawn mower 18, container 7, and grass collector 252. During automatic travel, the work machine control means 304 controls the PTO motor M0, etc. based on measurement results from the positioning means 301 and travel information and work machine information stored in the work information storage means 302 to control the operation of the lawn mower 18, container 7, and grass collector 252.

[0032] It is preferable to enhance safety by providing the tractor 1 with a sensor for detecting obstacles, and by having the driving control means 303 stop automatic driving when an obstacle is detected during automatic driving and resume automatic driving when the obstacle is removed. Here, it is preferable that when automatic driving is stopped, the work machine control means 304 control the lawnmower 18 and grass collector 252 to stop until automatic driving resumes, thereby reducing unnecessary power consumption. It is preferable that while an obstacle is detected, a warning is issued to those in the vicinity using a warning means such as a buzzer, lamp, or voice guidance.

[0033] The power measurement means 305 measures the power consumption of the traction motor 4 and the PTO motor M0 based on the measurement results of the power meter 202. In this embodiment, the power measurement means 305 measures the power consumption of the traction motor 4 and the power consumption of the PTO motor M0. The travel control means 303 requests power supply to the travel motor 4 so that the vehicle travels at a target speed according to operation. Therefore, as the travel load increases, the amount of power requested from the travel motor 4 increases to maintain the target speed. Therefore, by monitoring the power consumption of the travel motor 4, the load on the travel motor 4 can also be monitored. Similarly, the work machine control means 304 requests power supply to the PTO motor M0 so that the work machine (the lawn mower 18 or the grass collector 252) operates at a target operating speed. Therefore, as the work load increases, the amount of power requested from the PTO motor M0 increases. Therefore, by monitoring the power consumption of the PTO motor M0, the load on the PTO motor M0 can also be monitored. Therefore, the power measurement means 305 in this embodiment also has the function of measuring the load during travel and the load on the work machine through power consumption.

[0034] The power measurement result storage means 306 stores the measurement results of the power measurement means 305. In this embodiment, the power measurement result storage means 306 stores current consumption values, which are examples of power consumption values ​​measured by the power measurement means 305, and the rate of change of the current consumption values ​​(amount of change per unit time). The power measurement result storage means 306 stores the current consumption values ​​and rate of change at each coordinate in the field along the travel route during manual travel as reference values. The power measurement result storage means 306 also stores the current consumption values ​​and rate of change during automatic travel as work history information. This makes it possible to check the power consumption during automatic travel later. In particular, if power consumption history information is recorded for each section, it becomes possible to check the power consumption when the lawnmower 18 is operating and when it is not operating (while traveling within the field) for each section and area.

[0035] In addition, when working in multiple fields consecutively, the historical information on the power measurement results can be used to check the past power consumption for each field, and this can help the worker determine whether the remaining charge in the battery 5a is sufficient to work in the next field without charging, or whether it is better to charge the battery before moving to the next field. Therefore, it can also be used to create work plans.

[0036] The power supply control means 307 controls the power supply circuit E to control the power supply to each part of the tractor 1. During manual travel, the power supply control means 307 supplies power to the travel motor 4, PTO motor M0, etc. in accordance with the operator's manual operation. That is, it supplies power to the travel motor 4 so that the travel speed set by manual operation is achieved. It also supplies power in accordance with the operation to start / stop the lawn mower 18 and grass collector 252. It also supplies operating power to the hydraulic cylinder S1, etc. in accordance with the operation to discharge grass from the container 7.

[0037] In addition, during automatic driving, the power supply control means 307 controls the power supply (current consumption value and rate of change) based on the measurement results from the positioning means 301, the driving information and work machine information stored in the work information storage means 302, and the reference values ​​for the current consumption value and rate of change stored in the power measurement result storage means 306, so that the current consumption value and rate of change are the reference values ​​depending on the position of the field.

[0038] In the tractor 1 of this embodiment, the power supply control means 307 controls the power supply so that the current consumption value and rate of change are at reference values, but if at least one of the current consumption value and rate of change measured by the power measurement means 305 during power supply reaches a predetermined threshold, the power supply to the travel motor 4 is controlled to reduce the traveling speed (the supply current is reduced). In other words, if the load on the travel motor 4 or the PTO motor M0 reaches an upper limit (threshold) during automatic traveling, the power supply is limited to prevent the load from becoming any more excessive, thereby preventing damage to the travel motor 4, the PTO motor M0, the lawnmower 18, the grass collector 252, etc.

[0039] The charge control means 308 controls the charging of the battery 5a based on the remaining charge of the battery 5a measured by the battery remaining charge measuring means 204. In this embodiment, the charge control means 308 determines that it is time to charge the battery 5a when the remaining charge of the battery 5a falls below a predetermined value (charge determination value). When the charge control means 308 determines that it is time to charge the battery 5a during manual driving, it displays a message prompting the user to charge the battery. Furthermore, when the charge control means 308 determines that it is time to charge the battery 5a during automatic driving, it controls the travel motor 4, etc. via the travel control means 303, work machine control means 304, and power supply control means 307 to interrupt work and autonomously drive the tractor 1 to a charging position 411 to charge the battery 5a. The charge control means 308 in this embodiment includes a work interruption position storage means 308a, a charging route creation means 308b, a positioning means 308c, and a return route creation means 308d.

[0040] Figure 4 is an explanatory diagram of an example of a case where charging is performed during automatic traveling. The work interruption position storage means 308a stores a work interruption position 421 where work is interrupted when it is determined that it is time to charge during automatic traveling. In Figure 4, the work interruption position storage means 308a of the embodiment stores the coordinates of the work interruption position 421 in the field and the traveling direction (the direction of the tractor 1) as information about the work interruption position 421.

[0041] The charging path creation means 308b creates a charging path 422, which is a travel path from the work interruption position 421 to the charging position 411. The charging path creation means 308b in this embodiment selects the nearest (shortest) charging position 411 based on the coordinates of the work interruption position 421, and creates the charging path 422 from the work interruption position 421 to the charging position 411. In this embodiment, the charging path 422 is created so as to pass through unworked areas and not through areas where work has been completed. Note that there is a possibility that weeds have been removed in areas where work has been completed, and if the tractor 1 travels through an area where weeds have been removed, this is undesirable as it may disturb the removed grass. However, if weeds are not being removed or if it is acceptable for the tractor 1 to pass over removed grass, it is possible to create a path that passes through an area where work has been completed.

[0042] 5 is an explanatory diagram of the work vehicle during charging. The positioning means 308c aligns the position of a power receiving coil 431 (see FIG. 5) as an example of a power receiver of the tractor 1 with a power transmitting coil 433 as an example of a power transmitter of the charging device 432. The positioning means 308c in this embodiment aligns the position by running the tractor 1 so that the positions match based on the current position of the tractor 1 measured by the positioning means 301 and the pre-registered coordinates of the power transmitting coil 433 of the charging device 432.

[0043] It is also possible to mount a positioning device on the charging device 432, and have the charging device 432 and the tractor 1 communicate with each other, allowing the tractor 1 to acquire information on the current location of the charging device 432 and perform position adjustment. It is also preferable to display the current location of the tractor 1 and the location of the charging device 432 on a map on a terminal such as a tablet that remotely controls the tractor 1, making it easier for the operator to check. While the embodiment illustrates an example in which the tractor 1 is charged wirelessly, this is not limiting. After the tractor 1 stops at the charging position 411, a worker aboard the tractor 1 or a worker waiting at the charging position 411 can connect the charging device 432 and the tractor 1 with a charging cable to charge the tractor 1 via a wired connection.

[0044] Furthermore, in the embodiment, the power receiving coil 431 is installed on the underside of the container 7 at the rear of the tractor 1, but this is not limiting. The power receiving coil 431 can be installed in any position, such as on the underside of the traveling body 1a or in front of the traveling body 1a. Note that it is preferable that the power receiving coil 431 can be used as a power transmitting coil not only when charging the battery 5a but also when supplying power from the battery 5a to an external device in an emergency such as a disaster. Since the coils 431, 433 are expected to be used in the event of a disaster or outdoors, it is preferable that they are covered with resin or the like to be resistant to water and the like.

[0045] Furthermore, when wireless power transmission is performed using coils 431, 433, it is preferable to transmit power at a frequency higher than the frequency of the AC power supply, as this increases the efficiency of wireless power transmission. In the embodiment, an example is given of a single tractor 1 traveling in a field, but this is not limiting. In a large field, multiple tractors 1 may also travel. In this case, it is preferable that information about a charging device 432 in use among multiple charging devices 432 be shared with other tractors 1 that are working but not charging.

[0046] The return path creation means 308d creates a return path 423 (see FIG. 4 ) that returns from the charging position 411 to the work interruption position 421 after charging is completed. In the embodiment, the return path 423 is created so that the approach direction to the work interruption position 421 on the return path 423 matches the traveling direction at the work interruption position 421 when work was interrupted. Note that, although the embodiment describes a mode in which the return path 423 is created, this is not limiting. It is also possible to reduce the process of creating the return path 423 by traveling in the opposite direction along the charging path 422 to return to the work interruption position.

[0047] (Explanation of Flowchart) Next, the processing of the tractor 1 according to the embodiment will be explained using a flow chart, or so-called flowchart. Note that various processing of the tractor 1 other than that explained in the flowchart is processed in parallel, and detailed explanation and illustration thereof will be omitted.

[0048] (Explanation of Processing in Automatic Travel Mode of Tractor 1) Figure 6 is an explanatory diagram of a flowchart of processing in automatic travel mode of a tractor according to an embodiment. Figure 7 is an explanatory diagram of a flowchart of processing in automatic travel mode of a tractor according to an embodiment, and is a continuation of Figure 6. The processing in Figures 6 and 7 is started when the tractor 1 is started. In ST1 of Figure 6, it is determined whether or not an input operation to start the automatic travel mode has been performed. If yes (Y), proceed to ST2, and if no (N), repeat ST1.

[0049] In ST2, work information (travel information and work machine information) and reference information (reference values ​​for current consumption and rate of change) are read. Then, the process proceeds to ST3. In ST3, automatic travel to the work start position 402 begins. Then, the process proceeds to ST4. In ST4, it is determined whether the tractor 1 has arrived at the work start position 402 based on the current position of the tractor 1 and the coordinate information of the work start position 402. If yes (Y), the process proceeds to ST5; if no (N), ST4 is repeated. In ST5, the following processes (1) to (3) are executed, and the process proceeds to ST6. (1) Based on the travel information and reference information, travel begins at the travel speed along the travel path 401. (2) The lawnmower 18 is lowered. (3) The lawnmower 18 and the grass collector 252 are operated.

[0050] In ST6, it is determined whether the lawnmower 18 has reached the raised position 404a, 406. If yes (Y), proceed to ST7; if no (N), proceed to ST10. In ST7, the following steps (1) and (2) are performed, and then the process proceeds to ST8. (1) The lawnmower 18 is raised. (2) The lawnmower 18 is stopped. In ST8, it is determined whether the lawnmower 18 has reached the lowered position 404b, 407. If yes (Y), proceed to ST9; if no (N), ST8 is repeated. In ST9, the following steps (1) and (2) are performed, and then the process returns to ST6. (1) The lawnmower 18 is lowered. (2) The lawnmower 18 is activated.

[0051] In ST10, it is determined whether the container 7 has arrived at the grass discharge start position 408. If yes (Y), proceed to ST11; if no (N), proceed to ST12. In ST11, the container 7 is raised and weed discharge begins. Note that in this embodiment, grass mowing continues even while weed is being discharged, but it is also possible to have the lawnmower 18 or grass collector 252 stopped. Then, the process returns to ST6. In ST12, it is determined whether the container 7 has arrived at the grass discharge end position 409. If yes (Y), proceed to ST13; if no (N), proceed to ST14 in Figure 7. In ST13, the container 7 is lowered and weed discharge ends. Then, the process returns to ST6.

[0052] In ST14 of Figure 7, it is determined whether the remaining charge of the battery 5a has decreased. If yes (Y), proceed to ST15; if no (N), proceed to ST26. In ST15, the following steps (1) to (4) are executed, and then the process proceeds to ST16. (1) The coordinates and traveling direction of the work interruption position 421 are stored. (2) The lawnmower 18 is raised. (3) The lawnmower 18 and the grass collector 252 are stopped. (4) A travel route (charging route 422) to the charging position 411 is created. In ST16, travel to the charging position 411 begins along the charging route 422. Then, the process proceeds to ST17.

[0053] In ST17, it is determined whether or not the charging position 411 has been reached. If yes (Y), proceed to ST18; if no (N), repeat ST17. In ST18, alignment of the coils 431, 433 is performed. Then proceed to ST19. In ST19, it is determined whether or not alignment of the coils 431, 433 has been completed. If yes (Y), proceed to ST20; if no (N), repeat ST19. In ST20, charging of the battery 5a begins. Then proceed to ST21. In ST21, it is determined whether or not charging has been completed. If yes (Y), proceed to ST22; if no (N), repeat ST21.

[0054] In ST22, a return route 423 is created based on the coordinates and travel direction of the work interruption position 421. Then, the process proceeds to ST23. In ST23, travel begins from the charging position 411 toward the work interruption position 421 along the return route 423. Then, the process proceeds to ST24. In ST24, it is determined whether or not the work interruption position 421 has been reached. If yes (Y), the process proceeds to ST25; if no (N), ST24 is repeated. In ST25, the following steps (1) to (3) are executed, and the process returns to ST6 in FIG. 6 . (1) Based on the travel information and reference information, travel begins at the travel speed from the work interruption position 421 along the travel route 401. (2) The lawnmower 18 is lowered. (3) The lawnmower 18 and the grass collector 252 are operated.

[0055] In ST26, it is determined whether the work end position 403 has been reached. If yes (Y), proceed to ST27; if no (N), return to ST6 in FIG. 6. In ST27, the following steps (1) to (3) are executed, and then return to ST1 in FIG. 6. (1) Stop the tractor 1 from traveling. Note that in this embodiment, traveling is stopped, but this is not limited to this, and it is also possible to have the tractor automatically travel to a predetermined position outside the field or travel toward the next field. (2) Raise the lawnmower 18. (3) Stop the lawnmower 18 and the grass collector 252.

[0056] In the tractor 1 of the embodiment having the above configuration, power control during automatic driving is performed based on the current consumption value and change rate during manual driving. Therefore, automatic driving is performed based on the current consumption and change rate corresponding to the results of the operator's operation in response to the field conditions during manual driving, i.e., the driving and work load during manual driving. Conventional technologies that travel along a predetermined driving route make it difficult to respond to actual field conditions only after detecting the load, making it difficult to predict the load and respond in advance. Therefore, compared to cases where advance responses are made, power consumption is likely to be higher, leading to early battery depletion and the risk of running out of battery. In contrast, the embodiment allows the same tasks performed during manual driving to be performed automatically, enabling automatic driving with detailed operation content tailored to the actual field conditions during manual driving. Therefore, power consumption during automatic driving is reduced compared to conventional technologies, and the risk of running out of battery is reduced.

[0057] In addition, the tractor 1 of the embodiment also stores the lifting and lowering of the lawnmower 18 and the weed removal range (from the discharge start position 408 to the discharge end position 409) as work details for manual driving, allowing the same work to be automatically performed during automatic driving. Furthermore, in the tractor 1 of the embodiment, if the remaining charge of the battery 5a becomes low during automatic driving, the tractor 1 suspends operation and automatically travels to the charging position 411 to charge. This prevents the tractor 1 from becoming stranded due to a lack of power while working in the field. In particular, in the embodiment, after charging is complete, when the tractor 1 travels along the return path 423 to return to the work interruption position 421, its direction of travel is aligned with the direction of travel at the time of interruption, allowing for a smooth resumption of work from the work interruption position 421.

[0058] FIG. 8 is an explanatory diagram of a work vehicle according to another embodiment. In the embodiments shown in FIGS. 1 and 5, the power receiving coil 431 is installed on the underside of the container 7. However, this is not limited to this embodiment. As shown in FIG. 8, a solar cell panel 502 as an example of a power receiver can be installed on the top of the ROPS 501. The solar cell panel 502 generates electricity by receiving external light (including sunlight) and can charge the battery 5a. In the embodiment shown in FIG. 8, the solar cell panel 502 is configured so that its light-receiving surface faces horizontally outward and can receive light from all 360-degree directions. A configuration capable of receiving light from all 360-degree directions can be a combination of multiple flat panels, or a solar cell that can be formed into a curved surface, such as a perovskite solar cell, can be used.

[0059] The charging device 432' is also provided with an irradiator (an example of an optical wireless power supply device) 503 that irradiates light toward the solar cell panel 502 to generate power in the solar cell panel 502. Therefore, power can be transmitted wirelessly from the charging device 432' to the battery 5a using light by the solar cell panel 502 and the irradiator 503. For the light (an example of an electromagnetic wave) output from the irradiator 503, it is preferable to use laser light in terms of reach, but from the viewpoint of safety, illumination light or microwaves can also be used.

[0060] Therefore, from a safety perspective, it is preferable to emit laser light only after confirming that the solar cell panel 502 is within a range where power can be received. Therefore, when using laser light, it is preferable to provide a sensor camera 504 between the irradiator 503 and the solar cell panel 502 that detects the intrusion of an object, and to control the light emission to be interrupted when the intrusion of an object is detected. Specifically, it is preferable to interrupt the light emission when the sensor camera 504 detects an object within a cylindrical range whose central axis is a straight line connecting the irradiator 503 and the solar cell panel 502. This is because irradiating an object with laser light may ignite or cause a fire, and in the case of a human, may result in burns, blindness, or the like. It is preferable that the range for detecting the intrusion of an object be equal to or greater than the range where power can be received.

[0061] Although the orientation of the irradiator 503 can be set to a specific direction, it is preferable to change the direction of light irradiation horizontally or vertically. A configuration that can only irradiate light in a specific direction makes it difficult to charge the tractor 1 unless the tractor 1 moves to the charging position 411. However, by making the direction of light irradiation changeable, charging is possible anywhere in the field within the range of the light, eliminating the need for the tractor 1 to move to the charging position 411. Furthermore, by transmitting the current location of the tractor 1 to the charging device 432′ as needed and changing the direction of irradiation of the irradiator 503 so that the charging device 432′ tracks the tractor 1, the tractor 1 can work while charging. This reduces the number of times work is interrupted to charge, improving work efficiency. In addition, in order to deal with fluctuations in the height of the solar cell panel 502 due to unevenness in the field, it is possible to increase the height of the solar cell panel 502 or to install a marker on the side of the tractor 1 to indicate the height, detect the unevenness of the field from the height of the marker, and change the direction of light irradiation up or down.

[0062] In the embodiment shown in FIG. 8, the solar cell panel 502 is installed on the ROPS 501, but this is not a limitation. It can also be installed on the top of the container 7. Alternatively, in a work vehicle with a cabin, it can be installed on the upper surface of the cabin ceiling. It is preferable to position the solar cell panel 502 away from the driver's area, but it can also be installed on the side of the cabin after taking safety measures. It is also preferable for the solar cell panel 502 to be configured to receive light in all directions, 360 degrees, but this is not a limitation. It is also possible to configure the solar cell panel to receive light from a specific direction, or to configure a flat panel that can be rotated 360 degrees using a rotation device.

[0063] In the above embodiment, the tractor 1 is explained as being operated by the electric motor 4, M0, but is not limited to this. The present invention can also be applied to a tractor 1 equipped with an electric motor 4, M0 and an internal combustion engine (engine), i.e., a tractor equipped with a so-called hybrid engine. In this case, it is also possible to use a configuration in which the traveling and working equipment are driven by power from the engine, and the electric motor 4, M0 is used as an assist (auxiliary).

Claims

1. A vehicle body (1a); a work implement (18, 7, 252) supported by the vehicle body (1a) and operating during work in a farm field; an electric motor (4, M0) that drives a traveling device (2, 3) of the vehicle body (1a) and the work implement (18, 7, 252); and a power meter (202) that measures the power consumption value or the rate of change of power in the electric motor (4, M0). a control unit (300) for switching between an automatic driving mode in which the vehicle body (1a) is automatically driven along a predetermined driving route (401) while controlling the work machine (18, 7, 252) based on predetermined work information of the work machine (18, 7, 252), and a manual driving mode in which the work machine (18, 7, 252) is controlled while the vehicle body (1a) is driven in accordance with operation by a worker, and the control unit (300) controls the power consumption value or rate of change of power of the electric motor (4, M0) in the automatic driving mode based on measurement results of the power meter (202) when work is performed while the vehicle is driven in the manual driving mode.

2. The work vehicle according to claim 1, characterized in that it comprises: a work machine (18, 7) having a cutting device (18) that cuts grass in the field; and a storage section (7) that is supported by the vehicle body (1a) and stores grass cut by the cutting device (18), the storage section (7) being movable between a storage position where the grass can be stored and a discharge position where the grass can be discharged; and a control section (300) that automatically drives the vehicle body (1a) based on driving information including information on the driving speed of the vehicle body (1a), and controls the storage section (7) based on work machine information including information on grass discharge positions (408, 409).

3. The work vehicle according to claim 1 or claim 2, characterized in that it is provided with the control unit (300), which, when in the automatic driving mode, based on the measurement results of the power measuring device (202), when at least one of the power consumption value and the rate of change reaches a predetermined threshold, reduces the driving speed so that the threshold is not reached.

4. A work vehicle according to claim 1 or claim 2, characterized in comprising: a battery (5a) supported by the vehicle body (1a) and having power stored in the electric motor (4, M0); and the control unit (300) that, in the automatic travel mode, if the remaining charge of the battery (5a) falls below a predetermined value based on travel information including a charging position (411) in the field where the battery (5a) can be charged, interrupts work and sets a route for automatically traveling to the charging position (411) to charge the battery (5a), and after charging is complete, aligns the travel direction of the vehicle body (1a) with the travel direction at the time of interruption to set a route for automatically traveling to the position where work was interrupted.

5. A work vehicle as described in claim 4, characterized in that it comprises: a power receiver (502) that is placed at the charging position (411) and is capable of receiving power from an optical wireless power supply device (503) that transmits power by light, the power receiver (502) being supported on the vehicle body (1a); and a control unit (300) that performs work while charging within a range in which the power receiver (502) can receive power from the optical wireless power supply device (503).

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