Charging system

Abstract

To improve work efficiency compared to configurations where the charging position of a work vehicle is fixed.SOLUTION: By moving a power supply device (30) via a moving device (33) to a charging position where charging is possible from a power transmitter (36, 402) using a power receiver (21, 413), on the basis of the positioning result of a second positioning device (38) and the current position of a work vehicle (1), work efficiency can be improved compared to a configuration where the charging position of the work vehicle is fixed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charging system for externally charging a work vehicle equipped with a battery, and more particularly to a charging system capable of charging a work vehicle capable of traveling in a field. [Background technology]

[0002] There is known a technology in which an agricultural electric vehicle (4) is moved to a charging station (1) located adjacent to a farm and charged in a contactless manner (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-217225 Summary of the Invention [Problem to be solved by the invention]

[0004] With conventional technology, work vehicles travel to charging stations to charge. Therefore, the positions of the charging station and power feeding antenna are fixed, and the position of the power receiving antenna on the electric vehicle (position in the horizontal plane (latitude and longitude) and height in the direction of gravity) is also fixed. Therefore, if charging becomes necessary while working in a large field, the work must be interrupted and a trip to the charging station is made, which reduces work efficiency, i.e., the amount of work done per unit time. Furthermore, because the position of the power receiving antenna is fixed, even if an additional power receiving antenna is to be attached to an existing work vehicle, it may not be possible to attach it because the height is not suitable, which reduces versatility.

[0005] The present invention has as its technical object to improve work efficiency compared to a configuration in which the charging position of a work vehicle is fixed. [Means for solving the problem]

[0006] The above-mentioned problems of the present invention are solved by the following means. The invention described in claim 1 is a work vehicle (1) that has a first battery (7), a power receiver (21, 413) connected to the first battery (7), a first positioning device (22) that can measure a current position, a work machine (18) that performs work on a farm field, and that can travel in the farm field, a second battery (32) that stores electric power, and the power of the second battery (32) is transferred to the first battery (18) via the power receiver (21, 413). The charging system (S) is characterized by comprising a power supply device (30) having a power transmitter (36, 402) that transmits power to a work vehicle (7) in a non-contact manner, a second positioning device (38) that can measure the current position, and a moving device (33) that moves the work vehicle (1) from the power transmitter (36, 402) to a charging position where charging is possible using the power receiver (21, 413) based on the positioning result of the second positioning device (38) and the current position of the work vehicle (1).

[0007] The invention described in claim 2 is the charging system (S) described in claim 1, characterized in that it includes: the moving device (33) that causes the position of the power transmitter (36) to correspond to the position of the power receiver (21) in a horizontal plane; and a second moving device (D1) that is provided in the power supply device (30) and moves the power transmitter (36) in the direction of gravity, the second moving device (D1) causing the position of the power transmitter (36) to correspond to the position of the power receiver (21) in the direction of gravity.

[0008] The invention described in claim 3 is the charging system (S) described in claim 1, characterized in that it comprises the power supply device (30) having: a detection device (37) that detects the work vehicle (1); correction means (316) that corrects the current position of the work vehicle (1) measured by the first positioning device (22) based on the detection result of the detection device (37); and the movement device (33) that moves the power supply device (30) to a charging position based on the current position of the work vehicle (1) corrected by the correction means (316).

[0009] The invention described in claim 4 is the charging system (S) described in claim 1, characterized in that it includes a power receiver (413) connected to the first battery (7) via a first wiring (412), and the power receiver (413) can be installed at a position away from the vehicle body (1a) of the work vehicle (1) by extending the first wiring (412).

[0010] The invention described in claim 5 is the charging system (S) described in claim 1, characterized in that the power transmitter (402) is connected to the second battery (32) via a second wiring (401), and the power transmitter (402) can be installed at a position away from a main body of the power supply device (30) by extending the second wiring (401). [Effects of the Invention]

[0011] According to the invention of claim 1, by moving the power supply device (30) by the moving device (33) to a charging position where the power receiver (21, 413) can charge from the power transmitter (36, 402) based on the positioning result of the second positioning device (38) and the current position of the work vehicle (1), it is possible to improve work efficiency compared to a configuration in which the charging position of the work vehicle is fixed.

[0012] According to the invention of claim 2, in addition to the effect of the invention of claim 1, the charging efficiency can be improved by moving the position of the power transmitter (36) by the second moving device (D1) so that the position of the power receiver (21) corresponds to the position of the power receiver (21) in the direction of gravity.

[0013] According to the invention of claim 3, in addition to the effect of the invention of claim 1, by correcting the current position of the work vehicle (1) measured by the first positioning device (22) using the correction means (316) based on the detection result of the detection device (37), the deviation between the power receiver (21) and the power transmitter (36) is suppressed, and charging efficiency can be improved.

[0014] According to the invention of claim 4, in addition to the effect of the invention of claim 1, by extending the first wiring (412) and installing the power receiver (413) at a position away from the vehicle body (1a) of the work vehicle (1), the position of the power receiver (413) can be freely changed, enabling efficient charging.

[0015] According to the invention of claim 5, in addition to the effect of the invention of claim 1, by extending the second wiring (401) and installing the power transmitter (402) at a position away from the main body of the power supply device (30), the position of the power transmitter (402) can be freely changed, and efficient charging becomes possible. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is an explanatory diagram of a tractor as an example of a work vehicle according to an embodiment, in which FIG. 1(A) is an explanatory diagram of a state in which the work machine has been lowered to a height at which work is performed, and FIG. 1(B) is a plan view of a power supply device. [Figure 2] FIG. 2 is an explanatory diagram of a tractor as an example of a work vehicle according to an embodiment, with the work implement in a raised position. [Figure 3] FIG. 3 is a functional block diagram of the control unit according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram of another embodiment 1 of the present invention, and corresponds to FIG. [Figure 5] FIG. 5 is an explanatory diagram of another embodiment 2 of the present invention, and corresponds to FIG. [Figure 6] FIG. 6 is an explanatory diagram of Alternative Embodiment 3 of the embodiment, and corresponds to FIG. [Figure 7] FIG. 7 is an explanatory diagram of Alternative Embodiment 4 of the embodiment, and corresponds to FIG. [Figure 8] Figure 8 is an explanatory diagram of a farm in another embodiment 4, where Figure 8(A) is an explanatory diagram of a case where rails are placed in all rows of the travel path, and Figure 8(B) is an explanatory diagram of a case where rails are placed in every other row of the travel path. DETAILED DESCRIPTION OF THE INVENTION

[0017] FIG. 1 is an explanatory diagram of a tractor as an example of a work vehicle according to an embodiment, in which FIG. 1(A) is an explanatory diagram of a state in which the work machine has been lowered to a height at which work is performed, and FIG. 1(B) is a plan view of a power supply device. FIG. 2 is an explanatory diagram of a tractor as an example of a work vehicle according to an embodiment, with the work implement in a raised position. 1 and 2, a charging system S of the present invention includes a tiller tractor 1 as an example of a work vehicle, and a power supply device 30. The tractor 1 has 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 (an example of a drive source) 4 and a battery (an example of a first battery) 7 are mounted inside a hood 6 at the front 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 5 and is transmitted to the front wheels 2, 2 and the rear wheels 3, 3. A work implement such as a tiller 18 that tills the ground (field) behind the tractor 1 is attached to the rear of the tractor 1, and power is transmitted via a PTO shaft 9 to drive the work implement. In this specification, the left and right sides of the tractor 1 when viewed in the 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 backward direction is referred to as the rear side.

[0018] A driver's seat 8 is disposed above the transmission case 5 at the top of the traveling vehicle body 1a, and the driver's seat 8 is surrounded by a cabin 11. A steering wheel 10, a parking brake (not shown), and the like are 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) for 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.

[0019] In Figure 1, a hydraulic cylinder case 14 is provided above the rear of the transmission case 5, and lift arms 15, 15 are pivotally mounted on both the left and right sides of this hydraulic cylinder case 14. Lift rods 17, 17 are interposed and connected between the lift arms 15, 15 and lower links 16, 16, and a cultivator 18, an example of a working machine, is connected to the rear of the lower links 16, 16.

[0020] When hydraulic oil is supplied to the hydraulic cylinder 14a housed in the hydraulic cylinder case 14, the lift arms 15, 15 are rotated upward, and the work machine (cultivator) 18 is raised via the lift rod 17, lower link 16, etc. Conversely, when the hydraulic oil in the hydraulic cylinder 14a is discharged into the transmission case 5, which also serves as a hydraulic tank, the lift arms 15, 15 are lowered. In addition, the work implements attached to the rear of the traveling body 1a, i.e., the work implements to which drive is transmitted from the PTO shaft 9, are not limited to rotary tillage devices for agricultural work, but also include work implements such as plows, seed sowing machines, seedling transplanters, fertilizer spreaders, and pesticide spreaders.

[0021] A power receiving coil 21, which is an example of a power receiver, is housed in the front part inside the hood 6. The power receiving coil 21 is configured in the shape of a coil around which an electric wire is wound. The power receiving coil 21 is electrically connected to the battery 7. Furthermore, a positioning unit 22 as an example of a first positioning device is installed above the cabin 11. The positioning unit 22 of the embodiment incorporates a GNSS (Global Navigation Satellite System) receiver that receives signals from artificial satellites, an inertial measurement unit that measures the attitude of the traveling vehicle body 1a, i.e., the tilt in the front-to-back and left-to-right directions, by measuring the acceleration of the traveling vehicle body 1a in three axial directions, and the like. Therefore, the positioning unit 22 measures the current position of the tractor 1 by correcting the positioning results from the GNSS using the attitude measurement results from the inertial measurement unit, thereby improving accuracy compared to when positioning is performed using only the GNSS system. Note that, although it is preferable to use an inertial measurement unit from the perspective of improving positioning accuracy, it may not be provided depending on the design, specifications, required accuracy, etc.

[0022] The power supply device 30 has a casing 31 as an example of a device main body. A power supply battery (an example of a second battery) 32 is housed inside the casing 31. Four wheels (an example of a moving device) 33 are supported at the bottom of the casing 31. The wheels 33 are driven by a motor (an example of a drive source) M1 for the power supply device. Therefore, the power supply device 30 can move and travel as the wheels 33 are driven. The steering control of the power supply device 30 can be performed by changing the rotation speed of the left and right wheels 33, or two or four of the four wheels 33 can be used as steering wheels to enable steering. In addition, although the embodiment has been described with reference to a configuration using wheels 33 as an example of a moving device, the present invention is not limited to this, and crawlers (endless tracks) can also be used.

[0023] A power transmitting coil 36, which is an example of a power transmitter, is disposed on a side surface of the casing 31. The power transmitting coil 36 is supported by an elevating device (an example of a second moving device) D1 so that it can move in the direction of gravity relative to the casing 31, i.e., so that it can be raised and lowered. The power transmitting coil 36 can transmit power to the power receiving coil 21 in a non-contact manner using an electromagnetic induction system. Note that the method for non-contact charging is not limited to the electromagnetic induction system, and it is also possible to adopt, for example, a magnetic resonance system or a wireless energy transmission system using microwaves or laser light, or any conventionally known non-contact power transmission system. A camera 37, which is an example of a detection device, is disposed on the upper part of the casing 31. The camera 37 is capable of capturing an image of the tractor 1. Although the camera 37 is given as an example of the detection device, the detection device is not limited to this. For example, any detection device capable of detecting the tractor 1, such as a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), a sonic sensor, an optical sensor, or an infrared sensor, can be used.

[0024] Additionally, a second positioning unit 38 as an example of a second positioning device is supported on the upper part of the casing 31. Similar to the positioning unit 22, the second positioning unit 38 of the embodiment is configured to be capable of GNSS-based positioning and tilt measurement.

[0025] (Explanation of the control unit) FIG. 3 is a functional block diagram of the control unit according to the embodiment. In the block diagram of FIG. 3, elements that are not related to the description of the embodiment of the present invention are not shown or described. In the charging system of the embodiment, the tractor 1 is configured to be able to send and receive information to and from a server 101, which is an example of an information processing device, and a power supply device 30 via a communication line 100. The communication line 100 is preferably wireless communication such as a mobile phone line or a wireless LAN line, but wired communication is also possible.

[0026] (Description of the server's control section) The server 101 is configured with an information processing device, a so-called computer device. The control unit 110 of the server 101 can realize various functions by executing programs stored in a ROM (Read Only Memory), a RAM (Random Access Memory), or the like. The control unit 110 of the server 101 has the following functional means (functional modules) 111 to 115.

[0027] The field information storage means 111 stores information about fields where work is carried out by the tractor 1 and other work vehicles (not shown, such as rice transplanters, chemical sprayers, harvesters, etc.). Field information includes the location (latitude and longitude) of each field, its size, shape, and the location of the entrance and exit to the field. The work information storage means 112 stores information about work in each field. In this embodiment, the work information storage means 112 stores, as work information, the type of work previously performed in the field (plowing, sowing, chemical spraying, harvesting, etc.), the route during work, traveling speed, work speed, etc. In addition, information about work to be performed in the future in each field (type of work, work route, etc.) is also generated and registered.

[0028] The information receiving means 113 receives information transmitted from the tractor 1 and the power supply device 30. The information receiving means 113 in the embodiment receives and acquires information transmitted from each vehicle (tractor 1 and power supply device 30) about the current location of each vehicle, information about the capacity (remaining capacity) of the batteries 7 and 32, and the like.

[0029] The charging position setting means 114 sets a charging position where the battery 7 of the tractor 1 is charged from the power supply battery 32 of the power supply device 30. The charging position can be determined, for example, by calculating (predicting) the time when the remaining battery charge will reach a predetermined threshold (e.g., 10% remaining) based on the current remaining battery charge of the tractor 1, the type of work, and the power consumption per unit time, and setting the position of the tractor 1 on the work route at that time as the charging position. In this case, since the charging position may be near the center of the field, it is also possible to set the charging position to, for example, the edge of the field that is reached by continuing work along the work route after the threshold is reached, or the position where the tractor turns first after reaching the threshold. It is also possible to set the charging position to the edge of the field or the turning position before the threshold is reached. The charging position distribution means 115 distributes and transmits the charging position set by the charging position setting means 114 to the tractor 1 and the power supply device 30.

[0030] (Explanation of the control unit of the work vehicle) 3, the tractor 1 of the embodiment has a vehicle ECU 200 as an example of a control unit (control means) that controls each function. The vehicle ECU 200 of the embodiment is configured with a small information processing device, a so-called microcomputer. Therefore, the vehicle ECU 200 can realize various functions by executing programs stored in a ROM or the like.

[0031] (Input system description) Vehicle ECU 200 receives signals from signal output elements such as a GNSS receiver (an example of a positioning device) 201, an inertial measurement unit (an example of a positioning device) 202, a communication module 203, and various other sensors of positioning unit 22. The GNSS receiver 201 receives signals from GNSS (Global Navigation Satellite System) artificial satellites and measures the current position of the traveling vehicle body 1a. The inertial measurement unit 202 measures the acceleration of the traveling vehicle body 1a in three axial directions, thereby measuring the attitude of the traveling vehicle body 1a, that is, the tilt in the front-rear and left-right directions. The communication module 203 , which is an example of a communication device, transmits and receives information to and from the server 101 and the power supply device 30 .

[0032] (Description of output system) The vehicle ECU 200 outputs control signals to the travel motor 4, the steering wheel 10, the PTO shaft 9, the hydraulic cylinder 14a, the communication module 203, and other controlled elements. The traveling motor 4, which is an example of a drive source, controls the traveling speed of the traveling vehicle body 1a. The steering handle 10 adjusts the direction of the front wheels 2, 2 to control (steer) the traveling direction of the traveling vehicle body 1a. The PTO shaft 9 controls the rotation speed to start and stop the working machine 18 (cultivator, seed sower, fertilizer spreader, lawn mower, etc.). The hydraulic cylinder 14a raises and lowers the work machine 18.

[0033] Although not shown in the figure, the vehicle ECU 200, each component of the input system, and each component of the output system are driven by power supplied from the battery 7, or by the driving force of a motor, pump, etc. (not shown) that receives power from the battery 7.

[0034] The vehicle ECU 200 has the following functional means (functional modules) 211 to 218. The work information acquisition means 211 acquires information related to work sent and distributed from the server 101. In this embodiment, the work information acquisition means 211 acquires information related to the field where the tractor 1 will work (such as the location of the field and the location of the entrance and exit), information related to the work to be performed in the field (such as the type of work, work route, traveling speed, work implement speed), and information related to the work, such as the route for moving between fields and the guide route.

[0035] The first positioning means 212 measures the current position of the tractor 1 from the measurement results of the GNSS receiver 201 and the inertial measurement unit 202. When the GNSS receiver 201 is receiving radio waves from an artificial satellite, the first positioning means 212 in this embodiment corrects the GNSS-based positioning results with the measurement results of the inertial measurement unit 202 to improve accuracy, and when radio waves from the artificial satellite can no longer be received, measures (estimates) the current position of the tractor 1 based on the traveling direction measured by the inertial measurement unit 202 from the position at the time of the most recent radio wave reception and the traveling distance from the number of rotations of the wheels 2, 3. The first positioning means 212 in this embodiment transmits the positioning results to the server 101.

[0036] The travel control means 213 controls the travel, stopping and travel speed of the tractor 1 via the travel motor 4. During automatic travel, the travel control means 213 of the embodiment automatically travels the tractor 1 along a route (inter-field movement route, guidance route (route from entrance / exit to work start position within the field, route from work end position to entrance / exit), work route) according to the current position measured by the first positioning means 212, based on the work data acquired by the work information acquisition means 211. Furthermore, during manual driving, the driving control means 213 of the embodiment controls driving, stopping, and driving speed in response to the user's operation of the accelerator pedal 13 and the brake pedal 12. Note that during manual driving, it is also possible to configure the display panel to display routes (route for moving between fields, guide route, work route) and provide guidance (navigation).

[0037] The work implement control means 214 controls the operation, stopping, and working speed of the work implement 18, as well as the lifting and lowering of the work implement 18, via the PTO shaft 9 and hydraulic cylinder 14a. During automatic driving, the work implement control means 214 of this embodiment operates the work implement 18 at a working speed based on the work data acquired by the work information acquisition means 211. The work implement control means 214 also lowers the work implement 18 during work, and raises the work implement 18 before work starts, when turning, and after work is completed. During manual driving, the work implement 18 is controlled in response to the user's operation to lift and lower the work implement 18 and to start and stop the work implement 18.

[0038] The power management means 215 manages the power stored in the battery 7, i.e., the capacity (remaining capacity) of the battery 7. The power management means 215 of the embodiment continuously monitors (manages) the remaining capacity of the battery 7, which changes during driving or work, and transmits it to the server 101. The charging position acquisition means 216 acquires the information on the charging position transmitted from the server 101.

[0039] The charging position moving means 217 moves the tractor 1 toward the charging position acquired by the charging position acquisition means 216. In this embodiment, the charging position moving means 217 controls the traveling motor 4 and the steering wheel 10 via the traveling control means 213 to move the tractor 1 to the charging position. Note that the charging position moving means 217 stops the tractor 1 when the tractor 1 reaches the charging position based on the positioning result of the first positioning means 212. The charging control means 218 performs charging control to charge the battery 7 with power transmitted from the power supply device 30 through the power receiving coil 21 at the charging position. When the remaining amount of the battery 7 reaches a predetermined value (e.g., 90%), the charging control means 218 transmits a charging completion signal to the power supply device 30 and performs control to end the charging. Note that it is also possible to perform control such as performing rapid charging when the remaining amount is low, and slowing down the charging speed when the remaining amount reaches a certain level, or ending charging when the elapsed time from the start of charging reaches a predetermined time (e.g., 30 minutes) even if the remaining amount has not reached the predetermined value.

[0040] (Explanation of the control unit of the power supply device) The power supply device 30 of the embodiment has a power supply control unit 300 as an example of a control unit (control means) that controls each function. The power supply control unit 300 of the embodiment is configured by a small information processing device, a so-called microcomputer. Therefore, the power supply control unit 300 can realize various functions by executing programs stored in a ROM or the like.

[0041] (Input system description) The power supply control unit 300 receives signals from signal output elements such as the camera 37, the GNSS receiver (an example of a positioning device) 301 of the second positioning unit 38, the inertial measurement unit (an example of a positioning device) 302, the communication module 303, and various other sensors. The camera 37 captures an image of the tractor 1 as an example of an object outside the power supply device 30. The GNSS receiver 301 receives signals from GNSS (Global Navigation Satellite System) artificial satellites and measures the current position of the power supply device 30. The inertial measurement unit 302 measures the acceleration of the power supply device 30 in three axial directions, thereby measuring the attitude of the power supply device 30, that is, the tilt in the front-back and left-right directions. The communication module 303, which is an example of a communication device, transmits and receives information to and from the server 101 and the tractor 1.

[0042] (Description of output system) The power supply control unit 300 outputs control signals to the motor M1 for the wheels 33, the lifting device D1 for the power transmission coil 36, the communication module 303, and other controlled elements. The motor M1, which is an example of a drive source, drives the wheels 33 to control the traveling speed and direction. The lifting device D1 (an example of a second moving device) moves the power transmission coil 36 in the up and down direction, that is, lifts and lowers it. Furthermore, when the power supplying operation is started, the power transmitting coil 36 transmits the power of the power supply battery 32 to the battery 7 through the power receiving coil 21. Although not shown in the drawings, the power supply control unit 300, the components of the input system, and the components of the output system are driven by power supplied from the power supply battery 32.

[0043] The power supply control unit 300 has the following functional means (functional modules) 311 to 317. Similar to the first positioning means 212, the second positioning means 311 measures the current position of the power supply device 30 from the measurement results of the GNSS receiver 301 and the inertial measurement unit 302. Furthermore, the second positioning means 311 of the embodiment transmits the positioning result to the server 101. The charging position acquisition means 312 acquires the information on the charging position transmitted from the server 101.

[0044] The charging position moving means 313 moves the power supply device 30 toward the charging position acquired by the charging position acquisition means 312. The charging position moving means 313 of the embodiment controls the motor M1 based on the current position measured by the second positioning means 311 and the charging position to move the power supply device 30 to the charging position. Then, when the power supply device 30 reaches the charging position based on the positioning result of the second positioning means 311, the charging position moving means 313 stops the power supply device 30. When stopping the power supply device 30, the orientation of the power supply device 30 at the time of stopping is controlled so that the power transmission coil 36 faces the front side of the tractor 1 in the traveling direction. The lifting control means 314 lifts and lowers the power transmitting coil 36 via the lifting device D1. The lifting control means 314 of the embodiment controls the height of the power transmitting coil 36 in accordance with the height of the power receiving coil 21 of the tractor 1.

[0045] The vehicle detection means (displacement detection means) 315 detects the tractor 1 based on the camera 37. The vehicle detection means 315 detects the position of the tractor 1 moving to the charging position. In other words, it detects the relative position between the position of the power supply device 30 and the position of the tractor 1. Note that the detection of the position of the tractor 1 can be performed by image recognition, or it is also possible to set a marker (one or more) at a specific location on the tractor 1 and detect the distance and direction to the tractor 1 by reading the marker with the camera 37. Therefore, the vehicle detection means 315 detects the relative positional deviation (error) between the position of the tractor 1 stopped at the charging position based on the position measured by the first positioning means 212 and the power supply device 30 stopped at the charging position based on the position measured by the second positioning means 311, based on the image detected by the camera 37.

[0046] The deviation correction means 316 corrects the deviation detected by the vehicle detection means 315. The deviation correction means 316 of this embodiment corrects the current position of the tractor 1 measured by the first positioning means 212 using the detected deviation. In other words, the actual position of the tractor 1, which should be stopped at the set charging position, is corrected from the charging position to the actual stopped position. In the embodiment, when the position is corrected, the charging position moving means 313 and the lifting control means 314 control the positions of the power supply device 30 and the power transmission coil 36 so that they correspond to the position where the tractor 1 is actually stopped (the corrected position) and the position of the power receiving coil 21. It is also preferable to display the detected deviation on a display panel so that the worker can check it. However, the display is not limited to the display panel, and it can also be displayed on a tablet terminal or smartphone (not shown) that can communicate with the power supply device 30, the server 101, etc.

[0047] In the embodiment, the method of correcting the deviation has been described by moving the power supply device 30, but the present invention is not limited to this. For example, it is also possible to transmit information about the position deviation to the tractor 1, and move the tractor 1 by the amount of deviation. It is also possible to move both the power supply device 30 and the tractor 1 (moving them closer to or farther away from each other).

[0048] The power transmission control means 317 controls the power transmission coil 36 to charge the battery 7 of the tractor 1 from the power supply battery 32. When the power transmission control means 317 of this embodiment completes the correction of the deviation, it determines that the battery is ready for power transmission (charging) and starts power transmission. Then, in response to a control signal from the charging control means 218 of the tractor 1, it ends power transmission or controls the power transmission speed (charging speed). In addition, the charging efficiency (power transmission efficiency) is calculated from the amount of power transmitted by the power transmission control means 317 and the amount of charge by the charging control means 218, and if the charging efficiency does not reach a predetermined value, it is possible to fine-tune the positional relationship between the power transmission coil 36 and the power receiving coil 21 by slightly moving (running) the power supply device 30 or slightly raising and lowering the power transmission coil 36 so that the charging efficiency becomes high.

[0049] In the charging system S of the embodiment having the above configuration, when the remaining charge of the battery 7 of the tractor 1 reaches a threshold, a charging position is set and the power supply device 30 travels to the charging position. The battery 7 of the tractor 1 can then be charged at the charging position. Therefore, unlike the prior art, there is no need for the tractor 1 to move to a charging base in a fixed location, and the decrease in work efficiency caused by traveling to and from the charging base is suppressed. Therefore, work efficiency can be improved compared to a configuration in which the charging position of the work vehicle is fixed. The charging position is not limited to within the field, and can also be on a road such as a farm road or near a warehouse during maintenance.

[0050] In addition, in this embodiment, the power transmitting coil 36 is configured to be able to rise and fall, so even if the height of the power receiving coil 21 on the tractor 1 side differs depending on the model of tractor 1 or if the height of the power receiving coil 21 is displaced due to unevenness in the field, it is possible to adjust the position of the power transmitting coil 36. This makes it possible to improve charging efficiency, which can contribute to shortening charging time and improving work efficiency. In the embodiment, the power transmission coil 36 is movable up and down, but the present invention is not limited to this. The power reception coil 21 may be movable in the up and down direction.

[0051] In the embodiment, the power receiving coil 21 is installed at the front of the tractor 1, but the present invention is not limited to this. For example, the power receiving coil 21 may be installed on the right or left side of the tractor 1. Generally, it is preferable to place the battery 7 and the power receiving coil 21 as low as possible, as this lowers the center of gravity of the tractor 1 and makes driving more stable. Furthermore, the battery 7 is heavy and occupies a large volume, and it is easy to create space on the side (front, left side, or right side) of the battery 7 to place the power receiving coil 21 and other components, and there are fewer obstacles when receiving power, so it is preferable to place the power receiving coil 21 on the side of the battery 7. Therefore, it is preferable to install the power receiving coil 21 inside the silhouette of the battery 7 when viewed from the front.

[0052] Furthermore, although the embodiment has been described with reference to an example in which the work implement 18 is installed at the rear of the traveling body 1a, this is not limiting. For example, in a work vehicle in which a work implement is installed at the front or center of the traveling body 1a, such as a lawnmower, the battery 7 and the power receiving coil 21 can also be installed at a position at the rear of the traveling body 1a where no work implement is installed. Note that when the power receiving coil 21 is installed at the rear, it is possible to configure the battery 7 and the power feeding device 30 to charge the battery from the rear of the traveling body 1a, and by having the power feeding device 30 follow the rear of the traveling body 1a, it is possible to perform work while charging the battery.

[0053] Furthermore, although the embodiment has been described with reference to a non-contact charging method, the present invention is not limited to this. It is also possible to provide a work vehicle that is equipped with both a wired charging method and a non-contact charging method. In this case, the control unit (vehicle ECU 200) of the tractor 1 must be provided with a circuit and control means for switching between wired charging and non-contact charging. Furthermore, when storing the tractor 1 in a warehouse, barn, or the like, it is possible to provide charging equipment in the barn or the like to enable contactless charging, but continuing to charge the battery 7 after it has been fully charged may deteriorate the battery 7. Therefore, when storing the tractor 1 for a long period of time, it is preferable that the charging control means 218 controls the battery 7 so that it does not receive power from the power receiving coil 21 when the battery 7 is charged to a level above a predetermined remaining capacity.

[0054] (Other form 1) FIG. 4 is an explanatory diagram of another embodiment 1 of the present invention, and corresponds to FIG. In the configuration shown in Fig. 4, the power receiving coil 21 is installed on the lower front part of the traveling body 1a of the tractor 1. This makes it less likely that the center of gravity of the tractor 1 will be high compared to the configurations shown in Figs. 1 to 3. In the configuration shown in Fig. 4, the power receiving coil 21 is located near the underside of the traveling body 1a, forward of the front axle and rearward of the front bumper. Installing the power receiving coil 21 on the underside of the traveling body 1a can be easily done by modifying an existing tractor 1, improving versatility.

[0055] Furthermore, the power transmission coil 36 of the power supply device 30 is disposed at the bottom of the casing 31. The power transmission coil 36 is supported so as to be movable about a rotation axis 36a between a stored state along the side wall of the casing 31 and an expanded state along a horizontal plane. Therefore, in a non-charging state until the power supply device 30 moves to the charging position, the power transmission coil 36 is in the stored state, and when charging is performed at the charging position, the power transmission coil 36 can be expanded so that the power transmission coil 36 faces the power receiving coil 21.

[0056] (Other Form 2) FIG. 5 is an explanatory diagram of another embodiment 2 of the present invention, and corresponds to FIG. In the configuration shown in FIG. 5, the power receiving coil 21 is installed under the traveling body 1a of the tractor 1, but is installed closer to the center of the traveling body 1a than in the configuration shown in FIG. 4. Correspondingly, the power feeding device 30 is provided with a power transmitting coil (an example of a power transmitter) 402 connected by a power feeding cable 401, which is an example of a second wiring. After the power feeding device 30 has moved to the charging position, the worker can manually place the power transmitting coil 402 on the ground, and charging can be performed between the power transmitting coil 402 and the power receiving coil 21. Therefore, the worker can freely set and change the position of the power transmitting coil 402, allowing charging to be performed in a location that is easy to charge. This improves the efficiency of the charging operation.

[0057] In this case, it is also possible to install a positioning unit on power transmitting coil 402 to measure the current position of power transmitting coil 402, and then move tractor 1 to the charging position, using the position of power transmitting coil 402 as the charging position. Therefore, when tractor 1 needs to be charged, the charging position can be set in server 101, power supply device 30 can be moved to the charging position, and then the user can manually extend power feeding cable 401 from power supply device 30 to install power transmitting coil 402 on the ground, reset the position of power transmitting coil 402 as the charging position, and then move tractor 1 to the charging position, thereby enabling charging. In the configuration shown in FIG. 5, even if power receiving coil 21 is installed in a position where charging is difficult in the configuration shown in FIG. 4, power feeding cable 401 can be extended and charging can be performed.

[0058] (Other forms 3) FIG. 6 is an explanatory diagram of Alternative Embodiment 3 of the embodiment, and corresponds to FIG. 6, a socket 411 electrically connected to a battery 7 is provided on the hood 6 of the tractor 1. One end of a charging cable 412, which is an example of a first wiring, can be connected to the socket 411, and a power receiving coil (an example of a power receiver) 413 is connected to the other end of the charging cable 412. Therefore, when charging the battery 7, after the power supply device 30 and the tractor 1 arrive at the charging position, the power supply cable 401 is extended from the power supply device 30, the power transmitting coil 402 is placed on the ground, the charging cable 412 is connected to the socket 411, and the power receiving coil 413 is placed on the power transmitting coil 402, thereby enabling charging. Therefore, in addition to the configuration shown in Fig. 5, the position of the power receiving coil 413 can also be freely changed, improving the efficiency of the charging operation. Therefore, it is possible to retrofit the power receiving coil 413 to an existing tractor 1 that charges by wire via the socket 411, thereby enabling contactless charging.

[0059] (Other forms 4) FIG. 7 is an explanatory diagram of Alternative Embodiment 4 of the embodiment, and corresponds to FIG. Figure 8 is an explanatory diagram of a farm in another embodiment 4, where Figure 8(A) is an explanatory diagram of a case where rails are placed in all rows of the travel path, and Figure 8(B) is an explanatory diagram of a case where rails are placed in every other row of the travel path. In the configuration shown in Figures 7 and 8, a plurality of rails 421 are installed on the ceiling of a covered farm. The rails 421 extend along the travel path of the tractor 1 when working on the farm. The rails 421 can be arranged in all rows along the travel path 420 as shown in Figure 8(A), or they can be arranged in every other row as shown in Figure 8(B). The arrangement can be changed as appropriate depending on the design, specifications, usage conditions, etc., to every third row or every fourth row.

[0060] A power transmission coil 422 of the power supply device 30 is supported movably along each rail 421. Power can be supplied to the power transmission coil 422 through the rails 421. Power is supplied to the power transmission coil 422 only from the rail 421 that charges the tractor 1 from the current position of the tractor 1, thereby reducing wasted power supply. When the tractor 1 moves to the next row, power can be supplied efficiently by standby for power supply to the next row. It is also preferable to move the power transmission coil 422 in advance to the end of the row on the side where the tractor 1 is entering, in accordance with the timing when the tractor 1 moves to the next row.

[0061] In the configuration shown in Figures 7 and 8, a power receiving coil 423 is disposed on the top of the tractor 1. Therefore, depending on the current position of the tractor 1, the power transmitting coil 422 on the rail 421 above the tractor 1 can be moved to the position of the tractor 1 to charge the tractor 1. The configurations shown in Figures 7 and 8 have the advantage of not causing wear on the pantograph and extending its lifespan compared to a method of supplying power by contact with a pantograph or the like. 7 and 8, it is desirable to configure either or both of power transmitting coil 422 and power receiving coil 423 so that they can be raised and lowered in the vertical direction. This is because if the gap between power transmitting coil 422 and power receiving coil 423 is too narrow, the coils may come into contact with each other and be damaged, and if the gap is too wide, the power transmission efficiency may decrease.

[0062] It is desirable to charge the tractor 1 while it is stopped, but it is also possible to work with the tractor 1 while charging by moving the power transmission coil 422 at the same speed as the tractor 1's traveling speed. 7 and 8 show an example in which power transmitting coil 422 is installed on rail 421 on the ceiling, but this is not limiting. It is also possible to adopt a configuration in which power transmitting coil 422 is movable along rails or pipes installed underground along the travel route. In other words, the configuration is not limited to one in which power receiving coil 423 is installed on the top of tractor 1, and it is also possible to adopt a configuration in which the power receiving coil is installed on the underside of traveling body 1a of tractor 1. Furthermore, although the rail 421 has been illustrated as being installed on the ceiling of a roofed farm, this is not limited to this, and it is also possible for both ends of the rail 421 to be supported by pillars in an unroofed farm.

[0063] 7 and 8 illustrate an example in which the power transmission coil 422 moves, but the present invention is not limited to this. It is also possible to install a plurality of power transmission coils 422 at intervals along the rail 421 and charge continuously as the tractor 1 passes by. In this case, it is preferable to operate the power transmission coils 422 in accordance with the current position of the tractor 1, rather than activating all of the power transmission coils 422, thereby performing contactless charging without loss. [Explanation of symbols]

[0064] 1...Work vehicle, 1a...Vehicle body, 7...first battery, 18...Work equipment, 21,413...Power receiver, 22...first positioning device, 30...power supply device, 32...second battery, 33...mobile device, 36,402...Transmitters, 37...detection device, 38...second positioning device, 316...Correction means, 401...second wiring, 412...first wiring, D1...second moving device, S...Charging system.

Claims

1. a work vehicle (1) capable of traveling in a field, the work vehicle having a first battery (7), a power receiver (21, 413) connected to the first battery (7), a first positioning device (22) capable of measuring a current position, and a work implement (18) for performing work on the field; a power supply device (30) including: a second battery (32) storing electric power; a power transmitter (36, 402) that contactlessly transmits electric power from the second battery (32) to the first battery (7) via the power receiver (21, 413); a second positioning device (38) that can measure a current position; and a moving device (33) that moves the work vehicle (1) from the power transmitter (36, 402) to a charging position where charging is possible using the power receiver (21, 413) based on the positioning result of the second positioning device (38) and the current position of the work vehicle (1); A charging system (S) comprising:

2. the moving device (33) that causes the position of the power transmitter (36) to correspond to the position of the power receiver (21) in a horizontal plane; a second movement device (D1) provided in the power supply device (30) for moving the power transmitter (36) in a gravity direction, the second movement device (D1) causing a position of the power transmitter (36) to correspond to a position of the power receiver (21) in the gravity direction; Charging system (S) according to claim 1, characterized in that it comprises:

3. the power supply device (30) having a detection device (37) that detects the work vehicle (1), a correction means (316) that corrects the current position of the work vehicle (1) measured by the first positioning device (22) based on the detection result of the detection device (37), and a movement device (33) that moves the power supply device (30) to a charging position based on the current position of the work vehicle (1) corrected by the correction means (316); Charging system (S) according to claim 1, characterized in that it comprises:

4. the power receiver (413) connected to the first battery (7) via a first wiring (412), the power receiver (413) being installable at a position away from the vehicle body (1 a) of the work vehicle (1) by extending the first wiring (412); Charging system (S) according to claim 1, characterized in that it comprises:

5. the power transmitter (402) connected to the second battery (32) via a second wiring (401), the power transmitter (402) being installable at a position away from the main body of the power supply device (30) by extending the second wiring (401); Charging system (S) according to claim 1, characterized in that it comprises:

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