Work vehicle

Abstract

To provide a work vehicle which can perform by automatic steering, straightly-advancing travel and follow-up travel along a work trace of a previous process by imaging by an on-vehicle camera, a front ground surface during work traveling and a landscape which is a distant landscape of the front ground surface, even when the work vehicle has a safety frame on a rear side of a driver seat, and in which the on-vehicle camera does not interfere a front view field for the driver, even when the driver performs the straightly-advancing travel and follow-up travel by manual steering.SOLUTION: A work vehicle is configured so that an on-vehicle camera is a lifting type, and by lowering the on-vehicle camera from an imaging position of an image which is above a position near a rear part of a bonnet provided on a front part of a travel machine body, or is above a position near a front part of a panel cover continuous to the rear part of the bonnet, to a retreat position near an upper face near the rear part of the bonnet or near an upper face near the front part of the panel cover, a driver seated on a driver seat provided on a rear side of the panel cover and a steering handle can get an unobstructed view of the front ground surface and the distant landscape of the front ground surface through the bonnet, without being interfered by the on-vehicle camera.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a work vehicle, mainly for agricultural use, such as a tractor, and more particularly to a work vehicle equipped with an automatic steering device that performs straight-line driving or following the work tracks of the previous process based on images captured by an on-board camera. [Background technology]

[0002] When growing wheat, soybeans, vegetables, etc. in fields converted from rice paddies, etc., the moisture content of the soil causes poor seed germination and growth disorders, which hinders high crop yields. Therefore, a cultivation method is used in which ridges are made from the time of sowing to raise the cultivation bed and grow crops in moderately dry soil. When making ridges or sowing seeds at the same time as making ridges, a ridge-making machine or a seeding machine is attached to the rear of a tractor, and the ridge-making work is performed using these machines.

[0003] When forming (creating) many long ridges, each with a linear distance of about 50 to 200 meters, in a field converted from paddy field, etc., the first row of ridges is formed by running a tractor along the linear ridges that divide the field. If it is desired to create a straight ridge without relying on the ridges, for example, the tractor will reach the start point of the ridge to be created, set a distant mountain or building that matches the end point of the ridge as a target, and align a sight installed on the front of the tractor's bonnet with this to create a straight ridge.

[0004] Furthermore, the ridges in the next and subsequent steps are parallel to the row of ridges created in the first row (previous step) and have a specified row spacing compared to the row of ridges created in the previous step, so they are created by having the tractor follow along the work marks (ridge furrows, etc.) from the previous step. If the work machine is equipped with side markers that form V-shaped grooves in the ground, for example, a mark for creating the ridges in the next step is created using these side markers at the same time as creating the current ridge, and then, in the next step, the tractor is driven to run with the front of the bonnet aimed at this mark (V-shaped groove).

[0005] The above has explained how to drive when performing ridge creation work using an implement connected to a tractor. However, in order to create many linear ridges lined up with the specified spacing in a field that lacks straight-line stability, skilled tractor operation (steering) techniques are required. In addition, if the created ridges meander and subsequent maintenance work becomes difficult and the ridges have to be redone, extra effort and expenses will be incurred, such as the need to break up the created ridges and plowing them, or the waste of seeds, so it is work that is more demanding than it looks and does not allow for redoing and requires careful attention.

[0006] Therefore, in order to reduce the steering burden during work travel such as ridge making and to support the practice of efficient and highly accurate work, work vehicles equipped with cameras and automatic steering devices that perform straight travel or follow the work traces of the previous process based on images captured by the on-board camera have been researched, developed and put into practical use (see, for example, Patent Documents 1 and 2). In addition, on-board cameras to be equipped with these automatic steering devices and specific support structures for these cameras have also been researched (see, for example, Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2016-146061 A [Patent Document 2] JP 2017-211893 A [Patent Document 3] JP 2016-203788 A [Patent Document 4] Patent Publication No. 2022-79049 Summary of the Invention [Problem to be solved by the invention]

[0008] If a work vehicle is equipped with an automatic steering device that drives in a straight line or follows the work tracks of the previous process based on images captured by an onboard camera, the steering burden during work driving can be reduced and work can be performed with high precision and efficiency. In addition, an automatic steering device using GNSS (Global Navigation Satellite System) is known as a device that drives a work vehicle in a straight line in a similar manner, but this device does not have the problems of taking time for warming up the positioning device and setting the route, and automatic steering can be started quickly just by starting to capture images with the onboard camera.

[0009] Incidentally, when performing ridge making work, as described above, the driver manually steers the work vehicle while watching the ridges of the field, distant mountains or buildings, or traces of work from the previous journey, to make the work vehicle go straight or follow the traces. On the other hand, an automatic steering device that makes the work vehicle go straight or follow the traces of work from the previous journey based on images taken by an on-board camera makes the work vehicle go straight or follow the traces by substituting the on-board camera for the driver's eyes, so the camera used here needs to take pictures of the ground ahead and the scenery in the distance, just like the driver.

[0010] In other words, the on-board camera attached to a work vehicle needs to capture clear images required for image processing while fitting the ground ahead and the scenery in the distance into the frame while the vehicle is working. Therefore, as long as the on-board camera is composed of a single camera, the camera needs to be mounted at a slightly high angle (depressed angle) so that the horizon is captured near the top of the captured frame and the ground ahead, for example within 10 m of the work vehicle, is captured large overall near the bottom of the frame.

[0011] Therefore, as described in Patent Documents 1 to 3, the vehicle-mounted camera is installed inside the cabin covering the steering section of the work vehicle, more specifically, at the upper center in the left-right direction of the front window of the cabin, with a slightly shallow depression angle, facing the center in the forward direction of the work vehicle, so that the ground ahead during work travel and the scenery in the distance are captured in one frame. Also, the vehicle-mounted camera is configured to adjust the pitch angle and roll angle to obtain appropriate images.

[0012] However, tractors as work vehicles are not only provided with a cabin with a camera installed to cover the operation section. For example, vehicles called frame vehicles have been provided for some time that have an inverted U-shaped safety frame instead of a cabin behind the driver's seat to ensure the safety of the driver in the event of an unexpected rollover of the tractor. Therefore, even in such frame vehicles, a camera must be appropriately installed so that the vehicle can automatically steer for straight driving and following driving.

[0013] In this regard, the tractor with an inverted U-shaped safety frame without a cabin as described in Patent Document 4 has a support mechanism above the front side of the control section (rear end of the bonnet) to mount an on-board camera. In this case, the support mechanism is configured as an inverted U-shape that straddles the front side of the control section as a whole, and the height position of the support frame to which the camera is attached can be adjusted in multiple stages according to the seating height of the operator, so that the on-board camera does not obstruct the forward visibility of the operator sitting in the driver's seat.

[0014] Therefore, in order to mount an on-board camera at the same height as if it were mounted inside the cabin, a new support mechanism in an inverted U shape or the like must be provided in front of the steering wheel of the work vehicle for a work vehicle that does not have a cabin, which inevitably increases costs. Also, a support frame or the like that is provided higher than the driver sitting in the driver's seat is considered to be a front frame that protects the driver when the work vehicle rolls over, similar to a safety frame provided behind the driver's seat, and requires sufficient strength to ensure the safety margin necessary for protecting the driver, so an extremely thin frame that is only used to mount an on-board camera would not be strong enough.

[0015] When considering a new mounting position and mounting method that can properly mount the vehicle-mounted camera while avoiding such an increase in cost, for example, it is conceivable to mount the vehicle-mounted camera by attaching a bracket to the upper part of a safety frame installed behind the driver's seat. However, if the vehicle-mounted camera is installed above the safety frame behind the driver's seat, there is a risk that the driver's head may appear in the image captured by the camera depending on the driver's physique and posture, making it difficult to properly capture the ground ahead.

[0016] Also, it is conceivable to mount the on-board camera at a relatively low position in front of the bonnet that covers the driving part, taking into consideration the driver's field of vision. However, a work vehicle with left and right front wheels and rear wheels, such as a tractor, changes its direction of travel around a point (center of turning) that is roughly on the extension of the rear axle when the front wheels, which serve as steering wheels, are steered, so if the on-board camera is mounted in front of the work vehicle far away from the rear axle, the camera will be significantly swung left and right as the direction of travel changes, and the on-board camera will be close to the ground and will shoot a close-up of the ground in front of the vehicle, which is the subject, so there is a risk that the image will be distorted due to this influence.

[0017] Furthermore, if the on-board camera is provided above the safety frame as in the former case, it becomes impossible to use the safety frame to attach a sunshade that covers the driver above, and if the on-board camera is provided in front of the bonnet as in the latter case, it becomes impossible to attach a work machine such as a fertilizer spreader to the front of the vehicle. Furthermore, if the on-board camera is mounted directly on the bonnet, it will obstruct the driver's forward visibility, making it difficult to manually steer the work vehicle while driving for work.

[0018] In view of these problems, the present invention has an objective of providing a work vehicle that does not have a cabin covering the steering section, and that, for example, is equipped with a safety frame behind the driver's seat, can use an on-board camera to capture images of the ground ahead and the scenery in the distance while working, and can perform straight-line driving or following along work tracks from the previous journey using automatic steering, and furthermore, even when the driver performs such straight-line driving or following along tracks using manual steering, the on-board camera does not obstruct the driver's forward view. [Means for solving the problem]

[0019] In order to solve the above-mentioned problems, firstly, the work vehicle of the present invention is a work vehicle equipped with an automatic steering device that drives straight or follows the work tracks of the previous process based on images taken by an on-board camera of the ground ahead and the scenery in the distance while driving for work, and the on-board camera is of a lift-up type and can be lowered from the image taking position, which is either above the rear of the bonnet located at the front of the running body, or above the front of a panel cover continuing to the rear of the bonnet, to a retracted position close to the upper surface of the rear of the bonnet, or the upper surface of the front of the panel cover, so that a driver sitting in the driver's seat located behind the panel cover or steering wheel can view the ground ahead and the scenery in the distance through the bonnet without being obstructed by the on-board camera.

[0020] Secondly, the work vehicle of the present invention has a fixed leg erected on the upper part of a gate-shaped support frame erected on the running body, and an attachment arm extending from the vehicle-mounted camera is fitted into this fixed leg so as to be freely extendable and retractable to form a lifting mechanism for the vehicle-mounted camera, while the lifting mechanism is provided with guide means for regulating the extension range of the attachment arm to guide the vehicle-mounted camera to an image shooting position and a retracted position, and fixing means for disabling extension and retraction of the attachment arm to hold the vehicle-mounted camera at the image shooting position or the retracted position.

[0021] Furthermore, thirdly, the work vehicle of the present invention has a fixed leg attached to the upper part of the gate-shaped support frame using a fulcrum bolt in the left-right direction, and the pitch angle of the vehicle-mounted camera can be freely adjusted by rotating the fixed leg back and forth around this fulcrum bolt. Effect of the Invention

[0022] According to the work vehicle of the present invention, the work vehicle is equipped with an automatic steering device that drives straight or follows the work tracks of the previous process based on images taken by an on-board camera of the ground ahead and the scenery in the distance while working, and the on-board camera is height-adjustable and can be lowered from the image taking position, which is above the rear of the bonnet located at the front of the running body, or above the front of the panel cover continuing to the rear of the bonnet, to a retracted position close to the upper surface near the rear of the bonnet, or the upper surface near the front of the panel cover, so that the driver sitting in the driver's seat located behind the panel cover or steering wheel can view the ground ahead and the scenery in the distance through the bonnet without being obstructed by the on-board camera.

[0023] Therefore, even in work vehicles that do not have a cabin covering the control section, and for example have a safety frame behind the driver's seat, the on-board camera can be raised to a position to capture images, and the on-board camera can be positioned at a relatively high position on the running body, above the rear of the bonnet located at the front of the running body, or above the front of the panel cover that continues to the rear of the bonnet, so that images can be captured of the ground ahead and the scenery in the distance while working.The automatic steering device can then automatically steer the vehicle to travel straight or follow the work tracks of the previous journey based on the images captured by the on-board camera.

[0024] In addition, when the onboard camera is lowered from the image capture position to a retreat position, the onboard camera is positioned at a relatively low position on the running body near the upper surface of the rear of the bonnet or the upper surface of the panel cover near the front, allowing the driver sitting in the driver's seat to see the ground ahead and the scenery in the distance through the bonnet without being obstructed by the onboard camera.Therefore, the driver can manually steer the vehicle using, for example, a sight protruding from the front of the bonnet, and drive straight ahead, following a vehicle, or moving into a field, without any problems, just as if the onboard camera was not installed.

[0025] In addition, the on-board camera that takes an image at the upper rear of the bonnet or the upper front of the panel cover that continues to the rear of the bonnet is located at a relatively high position on the traveling vehicle body, but the height can be suppressed so that the driver sitting in the driver's seat does not notice the presence of the on-board camera unless he or she is aware of it when looking down ahead, and it does not extremely impair the driver's forward visibility. In addition, the on-board camera can be located at the rear where it does not interfere with opening and closing the bonnet, regardless of whether it is located at the image taking position or the retreat position.

[0026] Furthermore, according to the work vehicle of the present invention, a fixed leg is erected on the upper part of the gate-shaped support frame erected on the running body, and a mounting arm extending from the vehicle-mounted camera is fitted into this fixed leg so as to be freely extendable and contractible to form a lifting mechanism for the vehicle-mounted camera, while the lifting mechanism is provided with a guide means for regulating the extension range of the mounting arm and guiding the vehicle-mounted camera to an image shooting position and a retracted position, and a fixing means for disabling extension and contraction of the mounting arm and holding the vehicle-mounted camera at the image shooting position or the retracted position.

[0027] Therefore, the mounting support structure for the elevating type vehicle-mounted camera can be constructed compactly and inexpensively with the necessary strength by utilizing an existing gate-shaped support frame erected on the traveling body. Also, since there is no risk of the fixed legs and mounting arms that constitute the elevating mechanism of such a vehicle-mounted camera violating the driver's safety zone, it is not regarded as a safety frame such as a four-post type, and it is sufficient if it has the necessary support strength for the vehicle-mounted camera.

[0028] In addition, the guide means provided on the lifting mechanism can easily guide the vehicle-mounted camera to the respective positions when the mounting arm is extended and retracted from the fixed leg to switch the vehicle-mounted camera to the shooting position or the retreat position, eliminating the need for troublesome positioning adjustments. Furthermore, the fixing means provided on the lifting mechanism can hold the vehicle-mounted camera in the image shooting position or the retreat position, and in particular, the vehicle-mounted camera, which has been brought to the image shooting position determined by the guide means and then fixed by the fixing means, can reliably frame the ground ahead and the scenery in the distance during work driving, which is necessary for automatic steering.

[0029] Furthermore, with the work vehicle of the present invention, a fixed leg is attached to the upper part of the gate-shaped support frame using a fulcrum bolt in the left-right direction, and the pitch angle of the on-board camera can be freely adjusted by rotating the fixed leg back and forth around this fulcrum bolt.When this is done, the amount of subsidence of the vehicle body in the field varies depending on the weight of the work equipment connected to the work vehicle, and the accompanying change in the location of the ground ahead that is photographed can be eliminated by adjusting the pitch angle of the on-board camera, and work accuracy can be improved through appropriate automatic steering. [Brief description of the drawings]

[0030] [Figure 1] 1 is a side view of a tractor to which the present invention is applied. [Diagram 2] 1A and 1B are perspective views showing the mounting state of an in-vehicle camera, in which FIG. 1A is a state where the camera is raised to a position for capturing an image, and FIG. [Diagram 3] 1A and 1B are perspective views showing the mounting state of an in-vehicle camera without a panel cover, in which FIG. 1A is a state where the camera is raised to a position where an image is captured, and FIG. [Figure 4] 1A and 1B are exploded perspective views showing a mounting structure for an in-vehicle camera, in which FIG. 1A is a front view and FIG. [Diagram 5] FIG. 2 is a perspective view showing the steering handle and its surroundings of the steering section. [Figure 6] FIG. 2 is a block diagram of an automatic steering device. [Figure 7] The figures show the driving methods used in ridge making work: (a) is going straight ahead in the distance, (b) is following the ridge, (c) is following the previous path, and (d) is an explanatory diagram of following the V-groove. [Figure 8] 1A and 1B show a drive unit provided in a steering system for front wheels, in which (a) is a perspective view showing a state in which the drive unit is attached to the steering system, and (b) is a perspective view showing an internal structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] An embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, an agricultural tractor 1 as a work vehicle has a body (traveling body) that is integrally connected from the front to an engine 2, a clutch housing 3, a transmission case 4, etc. A bonnet 5 is provided near the front of the body, covering from above the driving part that is made up of the engine 2, its accessories, a battery, etc. This bonnet 5 is provided with headlamps 7 in a front grille section 6 on the front side, and a roughly triangular pyramid-shaped sight 8 protruding from the upper surface at the center of the left and right near the tip, so that the front side can be opened and closed freely around a pivot point provided at the rear.

[0032] Furthermore, front brackets 9, which extend forward with their bases fixed to the left and right sides near the bottom of the engine 2, support a front axle case (not shown) via a holder provided near the center so that it can swing left and right. Front axle cases (kingpin case and final case) are attached to the left and right ends of this front axle case. The front axle case supports a front axle 11 to which front wheels 10 are attached, and a steering handle 12 provided on the steering section steers the left and right front wheels 10 via a fully hydraulic power steering device.

[0033] Meanwhile, rear axle cases are provided on the left and right side surfaces of a differential housing (not shown) that is connected to the rear of the transmission case 4, and left and right rear wheels 14 are attached to rear axles 13 journaled on the left and right rear axle cases. Also, a well-known three-point link mechanism consisting of a top link 15 and left and right lower links 16, or a connecting device such as a drawbar, is provided at the rear of the vehicle body, and these connecting devices are used to connect working machines such as a rotary tiller, ridger, sower, or transplanter, and engine power is transmitted to the working machines from a PTO shaft (power take-off shaft) journaled on the rear of the differential housing.

[0034] Further, to the body below the clutch housing 3 rearward of the engine 2, there are attached via brackets a floor 17 constituting the floor of the steering section, a seat frame and rear wall for mounting a driver's seat 18 rising rearward from this floor 17, and left and right fenders 19 covering the upper front portions of the left and right rear wheels 14. Further, above the rear portion of the driver's seat 18, there is a safety frame 20 consisting of an inverted U-shaped roll bar which is foldably attached to the upper portion of a lower frame 20a fixed to the left and right rear axle cases, and further, left and right flasher lamps 21 are provided on this safety frame 20.

[0035] On the other hand, a gate-shaped support frame 22, the lower part of which is attached to the rear plate or the like at the rear of the engine 2 and erected, separates the driving section from the control section into front and rear sections, and a shielding plate (heat shielding plate) that blocks the high-temperature cooling air generated by the cooling fan of the engine 2 from reaching the control section is provided in the center of the gate-shaped support frame 22. Also, a fuel tank 23 for the engine 2 is attached to this gate-shaped support frame 22 so as to be behind the shielding plate, and the rear side of the above-mentioned bonnet 5 is attached to it so as to be freely rotatable via a bracket equipped with a fulcrum pin.

[0036] 8 is erected at the top near the front of the clutch housing 3 behind the gate-shaped support frame 22, and a power steering unit 25 is attached to the lower part of the steering column 24. A steering shaft 26 connected to the power steering unit 25 is fitted inside the cylindrical part of the steering column 25, and the steering handle 12 is attached to the upper end. A boot 27 is provided below the steering handle 12, and the upper part of the steering column 24 is covered by this boot 27.

[0037] The fuel tank 23, steering column 24, etc., which are provided behind the gate-shaped support frame 22, are covered with a resin panel cover 28 and a detachable rear panel cover 29, and of these, the panel cover 28 provided at the top is attached to the gate-shaped support frame 22 and the steering column 24, and a monitor panel 30 equipped with a tachometer, fuel gauge, warning lamps, etc., is provided on the top of the panel cover 28 at an angle so that the driver sitting in the driver's seat 18 can easily see the display surface, as shown in Figures 3 and 5. In addition to the monitor panel 30, the panel cover 28 also provides a switch panel 31 on which operation switches related to an automatic steering device, which will be described later, a changeover switch 32 for changing the display content of the monitor panel 30, an engine starter switch 33, etc., on the left and right sides near the bottom.

[0038] A forward / reverse switch lever 34, an engine control lever 35, etc. are provided on the left and right of the steering wheel 12, and a travel clutch pedal 36 and left and right brake pedals, etc. are provided on the floor 17 below the steering wheel 12. Also, on the left and right sides of the driver's seat 18, there are provided a main travel speed change lever 37, an auxiliary speed change lever, a PTO speed change lever, a work equipment lift lever, as well as setting devices for automatic control of the tractor 1, etc.

[0039] The outline of the tractor 1 has been explained above, but instead of the four-wheeled running gear employed by this tractor 1, a semi-crawler type (half track type) running gear may be employed in which the rear wheels 14 are track-type using rubber crawlers, for example. Also, the tractor 1 is equipped with a diesel or gasoline engine 2 as a power source for towing and driving the working equipment, but in these days when the shift to EVs is being called for, it goes without saying that an electric motor driven by a battery may also be used as a power source.

[0040] As mentioned above, the tractor 1 is used for tilling fields by connecting a rotary tiller, ridger, seeding machine, transplanter, or other working machine to the rear of the vehicle body, but when cultivating wheat, soybeans, vegetables, etc. in fields converted from paddy fields, it is customary to make ridges to raise the cultivation bed and grow them in moderately dry soil. To explain such ridge-making work, first, in order to remove weeds and create a flat planting field, a rotary tiller, for example, is connected to the tractor 1, and normal tilling work is performed while leveling out the unevenness of the field.

[0041] After a few days have passed since the field has been tilled in this way, the weeds have been removed and the soil has become somewhat firm, so next, ridge-making tools for making ridges are attached to the left and right rear parts of the rotary tiller connected to the tractor 1, or an attachment-type ridge-making tool is attached to the rear of the rotary tiller and used as a ridge-making machine. Alternatively, instead of a rotary tiller, a dedicated ridge-making machine that combines a ridge-making rotary tiller and a ridge-making tool into one unit may be used to make ridges.

[0042] If the ridges created are to be covered with polyethylene film to promote the growth of vegetables, etc., a mulching ridge making machine or ridge forming machine is used. If sowing or spraying of chemicals is to be performed at the same time as ridge creation, a sowing machine or sprayer is attached to the rear of the ridge making machine to reduce the labor required.

[0043] When a dedicated ridge-making machine or a mulch ridge-making machine is connected to this machine for operation, as shown in Figure 1, the ridge-making machine 38 uses a ridge-making rotary tilling device 39 to till the field with its tilling tines while pushing the tilled soil towards the center. The soil pushed towards the center is pressed and levelled by the inner surface of a ridge-forming plate 40 connected to the rear of the machine, creating ridges W in the field. Ground contact wheels 41 for adjusting the tilling depth are provided on the left and right sides towards the rear of the ridge-forming plate 40.

[0044] The mulching device also has a holder that holds a film roll 42 above the ridge forming plate 40, and a presser roll 43 provided below the film roll 42 presses the film unwound from the film roll 42 against the surfaces of the ridges W, shaping the surface of the ridges W. Then, both ends of the film covering the ridges W are pressed by left and right treading wheels 44 and covered with soil by soil covering wheel 45, thereby laying the mulch film.

[0045] The types of ridges include flat ridges, high ridges, and intermediate ridges such as rectangular ridges, depending on the height of the ridges to be formed, as well as trapezoidal and mountain-shaped ridges, and some can create one or many ridges at a time. For this reason, manufacturers provide multiple types of ridge-making machines, and users perform ridge-making work using a ridge-making machine of a suitable type while taking into consideration the capacity of the tractor 1. When performing ridge-making work in a field, the driver tries to make the ridges as straight and neat as possible to make subsequent management work easier, and also tries to make as many rows of ridges (rows) as possible to efficiently use the field.

[0046] Therefore, in response to the demand for performing such ridge-making work, tractors equipped with automatic steering devices that perform straight-line driving or following the work tracks of the previous process based on images captured by an on-board camera have been developed and put into practical use. However, in order to capture images of the ground ahead and distant scenery with a camera while the tractor is working, it has been the default to install the camera inside the cabin, especially in the upper center of the front window, from the viewpoints of providing good visibility from the vehicle body and being able to utilize existing structures, and therefore the development of tractors without a cabin has been delayed.

[0047] Therefore, the present invention aims to provide a tractor 1 equipped with such an automatic steering device in a so-called frame vehicle that does not have a cabin. Below, the automatic steering device equipped in the tractor 1 will be explained. As shown in the block diagram of Figure 6, the automatic steering device comprises an on-board camera (camera module) 46, a single-board computer for image processing (image processing SBC) 47 equipped with a wireless LAN function, an electronic control unit for automatic steering (automatic steering ECU) 48, and a mobile terminal (tablet terminal or smartphone) 49, etc.

[0048] Among these, the on-board camera 46 uses, for example, a board-type CMOS camera module with monochrome output of 300,000 pixels or the like, which is composed of a lens, an IR cut filter, an image sensor, a control electronic circuit, etc., and outputs image data captured at a predetermined cycle to the image processing SBC 47. Also, this image processing SBC 47 is attached to the board of the camera module 46 via a spacer, and issues an image capture command to the camera module 46, and performs necessary image processing (pattern matching, etc.) on the acquired image data, thereby calculating the target steering angle of the front wheels 10 required when the tractor 1 travels straight ahead or follows a vehicle.

[0049] Since the image processing SBC 47 is equipped with a wireless LAN function, the image captured by the camera module 46 can be wirelessly transmitted and displayed on a display of a mobile terminal 49 such as a tablet terminal or a smartphone. Meanwhile, the target steering angle of the front wheels 10 calculated by the image processing SBC 47 is transmitted to the automatic steering ECU 48 via an in-vehicle network, and the automatic steering ECU 48 drives and rotates an electric motor (stepping motor) 51 provided in a drive unit 50 so that the steering angle of the front wheels 10 coincides with the commanded target steering angle.

[0050] 8, the drive unit 50 provided in the steering system of the front wheels 10 includes a gear reduction mechanism formed of a pair of a helical gear 53 housed in a two-piece case 52 and coupled to the middle of the steering shaft 26 using serrations, and a helical gear 54 provided on a drive shaft driven and rotated by a stepping motor 51. When the automatic steering ECU 48 rotates the stepping motor 51 forward or reverse, the steering shaft 26 is rotated by the driving force reduced by the gear reduction mechanism, and the front wheels 10 can be steered via the power steering unit 25 accordingly.

[0051] On the other hand, when the driver operates the steering wheel 12 while the front wheels 10 are being automatically steered in this manner, the manual operating force applies a load to the helical gear 54 of the gear reduction mechanism, causing the drive shaft to move in the axial direction. Then, when this movement is detected by the displacement meter 55 consisting of a potentiometer, the automatic steering ECU 48 cuts off the excitation current to the stepping motor 51, causing the self-holding force of the stepping motor 51 to disappear and releasing the automatic steering.

[0052] Therefore, the automatic steering ECU 48 always aims to ensure that work is performed safely by prioritizing the driver's manual steering over automatic steering. The automatic steering ECU 48 also includes a steering angle sensor 56 in the steering system of the front wheels 10, and when the steering angle sensor 56 detects that the front wheels 10 have been steered to the left or right by more than 40 degrees, for example, it determines that the tractor 1 is turning or the like on the headland, and in this case too, the automatic steering is released. Furthermore, the traveling speed of the tractor 1 is detected by image analysis or the like, and if the speed is too high for automatic steering, the automatic steering is released.

[0053] Next, the function of such an automatic steering device when performing ridge formation work will be explained. First, when performing ridge formation work in a farm field, creating the first ridge in a straight line is important for creating the ridges in the second and subsequent ridges. Therefore, when creating this first ridge, the device automatically steers so that the tractor 1 runs (straight line) on a straight line connecting a target point based on a distant landscape (distant view) in front of the tractor 1 and a starting point where the tractor 1 was moved forward to start work, as shown in "distant view straight ahead" in Figure 7(a).

[0054] When the driver uses this distant view straight ahead function, he or she selects distant view straight ahead mode in the automatic steering control by setting the mode switching rotary switch 57 provided on the switch panel 31 of the steering wheel to the "straight ahead / distant view" position as shown in Fig. 5. Also, he or she presses the automatic steering button (switch) 58 provided on the switch panel 31 to turn the automatic steering control ON. When the automatic steering switch 58 is turned ON, the automatic steering ECU 48 causes the automatic steering LED 59 provided to the left of it to flash.

[0055] Also, at the work start position in the field, the target point for straight ahead in the distance is determined by visual inspection, and then, while starting work, the tractor 1 is manually steered forward 5 to 10 m so that the lateral center of the tractor 1 faces the target point (fixing the target and ensuring straight-ahead movement). Then, when the image processing SBC 47 automatically sets the scenery near the lateral center near the top of the frame as the target, it turns on the detection LED 60 instead of turning off the non-detection LED 61 of the switch panel 31. Therefore, when it is confirmed that this is turned on and the automatic steering button 58 is pressed again, the target point is fixed, and the image processing SBC 47 and the automatic steering ECU 48 work together to start automatic steering of the tractor 1 (automatic steering LED 59 turns on).

[0056] If the driver presses the automatic steering button 58 as the tractor approaches the end of the first journey, or if the image processing SBC 47 recognizes based on the camera image that the tractor has passed the end of the journey, the automatic steering ECU 48 cancels automatic steering using the distant view straight ahead function (automatic steering LED 59 turns off). In addition, when creating the ridges for the first journey, if the ridges dividing the field are made relatively straight and it is desired to create the ridges from the edge of the ridges, the ridge following function shown in Fig. 7(b) can be used instead of the distant view straight ahead function, and in this case, the tractor 1 automatically steers so as to travel parallel to and follow the ridges (following travel).

[0057] When the driver uses this ridge following function, he or she sets the mode changeover rotary switch 57 provided on the switch panel 31 to the "follow-ridge" position to select the ridge following mode in the automatic steering control. Also, he or she presses the automatic steering button 58 provided on the switch panel 31 to turn the automatic steering control ON. When the automatic steering switch 58 is turned ON, the automatic steering ECU 48 similarly causes the automatic steering LED 59 provided to the left of it to flash.

[0058] Furthermore, the tractor 1 is aligned so that it is parallel to the ridge at the work start position in the field. Work is started by manual steering, and the tractor 1 is moved forward 5 to 10 m while maintaining a distance from the ridge (detecting the ridge and ensuring straightness). Then, when the image processing SBC 47 detects a step that is 10 cm or higher above the ground based on the camera image, it turns on the detection LED 60 instead of turning off the non-detection LED 61. Therefore, when the user confirms that this is on and presses the automatic steering button 58, the image processing SBC 47 and the automatic steering ECU 48 work together to start automatic steering of the tractor 1 (automatic steering LED 59 turns on).

[0059] In this case, the image processing SBC 47 and the automatic steering ECU 48 perform automatic steering while maintaining the distance between the tractor 1 and the ridge when the above-mentioned automatic steering button 58 is pressed again, so that the ridge can be created at a desired distance from the ridge. Also, if the driver presses the automatic steering button 58 as the tractor approaches the end of the journey, or if the image processing SBC 47 recognizes based on the camera image that the tractor has passed the end of the journey, automatic steering by the ridge following function is released (automatic steering LED 59 is turned off).

[0060] The above has been an explanation of the case where the first ridge is created in the first stroke, but when creating ridges in the second stroke and thereafter, they are created using "previous stroke trace following," which performs automatic steering to follow the work trace of the ridge created in the previous stroke, as shown in Fig. 7(c), or "V groove following," which performs automatic steering to follow a V groove made in the ground by, for example, a side marker 62 attached to the tool bar of the work machine during the previous stroke, as shown in Fig. 7(d). When the driver uses the previous stroke trace following function or V groove following function, he or she sets the mode changeover rotary switch 57 provided on the switch panel 31 to the "follow-previous stroke" or "follow-V groove" position to select the previous stroke trace following mode or V groove following mode in the automatic steering control.

[0061] After this, the driver turns on the automatic steering control by pressing the automatic steering button 58, aligns the tractor 1 at the work start position so that it is parallel to the work marks of the ridges created in the previous process, or aligns the left and right center of the tractor 1 with the V-groove line marked by the side marker 62 at the work start position, etc., which are similar to the automatic steering control in the ridge following mode described above and will not be explained here. In this case, the image processing SBC47 recognizes a step (10 cm or more) that is lower than the ground as a work mark, and also recognizes one with a width (20 cm) and height (5 cm) of a specified value or more as a V-groove, and the clearer these corners are, the easier they are to recognize.

[0062] Furthermore, if the steering wheel 12 turns too much or too slowly due to the hardness or softness of the field during the above-mentioned automatic steering, causing the driver to feel that the steering amount of the front wheels 10 is excessive or insufficient, then when the driver presses the high / medium / low sensitivity adjustment buttons (switches) 63, 64, 65 provided on the switch panel 31, the automatic steering ECU 48 controls the electric motor 51 with the commanded steering amount, and the adjustment status is displayed by the lighting status of the high / medium / low sensitivity LEDs 66, 67, 68. Also, when automatic steering operation is not performed, after work is completed, or when driving on public roads, the automatic steering button 58 is pressed to turn automatic steering OFF.

[0063] Next, the mounting structure of the vehicle-mounted camera 46 to the tractor 1, which is a feature of the present invention, will be described. As shown in Fig. 4, the camera module 46, which has a lens, IR cut filter, image sensor, control electronic circuitry, etc. mounted on one board (substrate), is attached to a mounting bracket 70 formed by bending into a U-shape for the camera module from the rear by screwing it through a mounting plate 71, with a board 47a mounting an image processing SBC 47 attached to the rear using a spacer 69. A wireless communication antenna 72 is attached near the top of this mounting bracket 70.

[0064] The lens of camera module 46 and its holder portion 46a protruding from opening 70a formed in the front surface of mounting bracket 70 are supported by a positioning sponge 73. Furthermore, front case 74, which covers camera module 46 from the front, has front cover 77 attached to its front surface, with glass plate 75 fitted together with packing 76, and resin rear case 78, which is screwed to front case 74 from the rear, covers image processing SBC 47 and the like from the rear side.

[0065] The on-board camera 46, housed in the camera cases 74, 78 for the purposes of waterproofing and dustproofing, is capable of photographing the ground and distant scenery within about 10 m ahead of the tractor 1 while the tractor 1 is working, so that the tractor 1 can perform straight-line driving and following driving along the work tracks of the previous process using the automatic steering control described above. At the same time, it is necessary to devise a way to ensure that the on-board camera 46 does not obstruct the driver's view of the road ahead, even when the driver performs straight-line driving and following driving using manual steering.

[0066] Therefore, the on-board camera 46 is made to be liftable, and can be lowered from an image capturing position which is either above the rear of the bonnet 5 provided at the front of the running body, or above the front of the panel cover 28 continuing to the rear of the bonnet 5, to a retracted position close to the upper surface of the rear of the bonnet 5, or the upper surface of the front of the panel cover 28, so that the driver sitting in the driver's seat 18 provided behind the panel cover 28 and steering wheel 12 can view the ground ahead and the scenery in the distance through the bonnet 5 without being obstructed by the on-board camera 46.

[0067] That is, a gate-shaped support frame 22 equipped with a shielding plate that divides the driving section and the steering section into front and rear sections is erected from the vehicle body slightly behind the rear of the bonnet 5, and this gate-shaped support frame 22 has sufficient strength because, in addition to the shielding plate, it also provides a pivot point for the bonnet 5 and is used as a frame for mounting and supporting the fuel tank 23 and panel cover 28. Therefore, by utilizing this gate-shaped support frame 22, it is planned to mount the on-board camera 46 compactly while minimizing shaking of the on-board camera 46.

[0068] That is, a reinforcing plate 79 for mounting the vehicle-mounted camera 46 in the left-right direction is attached by welding to the upper part of the gate-shaped support frame 22. Also, L-shaped metal fittings 80 are fixed to the upper surface of this reinforcing plate 79 near the left and right ends, respectively, and the lower parts of left and right fixed legs 81 are attached to the left and right side plate parts formed by bending this metal fitting 80 by using fulcrum bolts 82 and nuts in the left-right direction to stand upright. The left and right fixed legs 81 used here are formed into a square pipe, for example, with a main body 81a formed into a U-shape using light grooved steel, and the open side of the main body 81a is covered with a flat plate 81b.

[0069] Meanwhile, the mounting bracket 70 of the vehicle-mounted camera 46 is provided with left and right mounting arms 70b that extend while being bent downward from the left and right side plate portions 70a. The left and right mounting arms 70b extending from the vehicle-mounted camera 46 are inserted from above into left and right fixed legs 81 erected on the upper part of the gate-shaped support frame 22, and the left and right mounting arms 70b are fitted telescopically to the left and right fixed legs 81 to form a lifting mechanism for the vehicle-mounted camera 46.

[0070] In addition, left and right linear slots 81c, 81c are drilled in the main body 81a of the fixed leg 81, and a guide pin 83 is passed through the slots 81c, 81c from the outside and attached to the lower ends of the left and right mounting arms 70b. In this case, when the left and right mounting arms 70b are pulled upward from the fixed leg 81 to extend them, the guide pin 83 fits into the slot 81c and moves upward along the linear end surface of the main body 81a that forms the slot 81c.

[0071] Furthermore, when the guide pin 83 reaches the upper end of the groove 81c and then fits into the locking groove 81d that extends slightly forward from the upper end of the groove 81c, the left and right mounting arms 70b extend to their maximum and guide the vehicle-mounted camera 46 to the image capture position.In this case, even if the hands holding up the vehicle-mounted camera 46 are released, the guide pin 83 rides up and is supported on the lower end surface of the main body 81a that forms the locking groove 81d, so the vehicle-mounted camera 46 will not drop.

[0072] Furthermore, when the guide pin 83 fitted in the locking groove 81d is moved backward in the opposite direction and then lowered through the linear groove 81c, the guide pin 83 reaches the lower end of the groove 81c and abuts against the lower end face of the main body 81a that forms the groove 81c, thereby guiding the on-vehicle camera 46 to the retracted position, and the weight of the on-vehicle camera 46 is supported by the fixed leg 81. Therefore, the guide means formed by the above-mentioned guide pin 83 and the grooves 81c and 81d can regulate the extension and contraction range of the mounting arm 70b, and can easily guide the on-vehicle camera 46 to the image shooting position and the retracted position.

[0073] However, if the guide pin 83 is simply fitted into the locking groove 81d, there is a risk that it may unexpectedly come out of the locking groove 81d, or that the mounting arm 70b fitted to the fixed leg 81 and the in-vehicle camera 46 attached thereto may swing around on their own due to vehicle vibration, etc. Therefore, a screw hole is provided in the rear end portion near the top of the main body 81a of the fixed leg 81, and a knob bolt 84 is attached from the rear.

[0074] Therefore, the tip surface of the tightened knob bolt 84 presses the mounting arm 70b toward the flat plate 81b, making the mounting arm 70b non-retractable and preventing it from shaking. By using this fixing means using the knob bolt 84 in the lifting mechanism for the on-board camera 46, the on-board camera 46 can be reliably held without shaking at the image shooting position or at the retracted position, and when lifting or lowering the on-board camera 46, the knob bolt 84 can be loosened or removed.

[0075] 2 and 3, a portable terminal mounting base 28a is integrally formed on the upper surface near the front of the panel cover 28 provided on the control panel, so that the driver sitting in the driver's seat 18 can view the display of the portable terminal 49 while driving to work. An opening 28b is provided near the lower front of the mounting base 28a, and the opening 28b faces the fuel filler hole 23a of the fuel tank 23, so that the cap 23b of the fuel tank 23 can be attached and detached from above the opening 28b to replenish fuel.

[0076] The aforementioned panel cover 28 is positioned above and covers the gate-shaped support frame 22 on which the vehicle-mounted camera 46 is mounted, and the fixed legs 81 that constitute the lifting mechanism for the vehicle-mounted camera 46 are raised through the front left and right sides of the opening 28b provided in the panel cover 28 to avoid interference with the cap 23b of the fuel tank 23. Therefore, when assembling the lifting mechanism for the vehicle-mounted camera 46, the fixed legs 81 etc. are attached before attaching the panel cover 28.

[0077] The power cable supplying power to the camera module 46 and the image processing SBC 47 and the communication cable connecting to the automatic steering ECU 48 are bundled as a wire harness, passed through the inside of the tube of one of the mounting arms 70b, and led out from the lower part of the fixed leg 81 to above the fuel tank 23. Moreover, since the cables are connected to the connectors leading out from the automatic steering ECU 48 and the like and routed while the upper part is covered with the bonnet 5 and the panel cover 28, there is no risk of the cables leading out from the in-vehicle camera 46 being exposed to the outside and spoiling the appearance.

[0078] Then, as shown in Figure 1 or Figure 2 (a), when the vehicle-mounted camera 46 is raised and held at an image capturing position that is above and toward the rear of the bonnet 5 provided at the front of the running body, or above and toward the front of the panel cover 28 that continues to the rear of the bonnet 5, the vehicle-mounted camera 46 can capture images of the ground about 10 m ahead of the vehicle-mounted camera 46 and the scenery in the distance.

[0079] In other words, if a tangent line S is drawn from the ground 10 m horizontally ahead of the vehicle-mounted camera 46 to the curved surface of the tip of the bonnet 5, and the capturing position of the image of the vehicle-mounted camera 46 is set so that the tangent line S coincides with the underline u of the vertical angle of view α of the vehicle-mounted camera 46, a desirable image can be obtained in which the ground 10 m ahead and the scenery in the distance fill the frame without the bonnet 5 just fitting into the frame captured by the vehicle-mounted camera 46.

[0080] However, if the field is soft or the weight of the work machine connected to the tractor 1 increases, the tractor 1 sinks more into the ground, causing the ground surface to rise relatively with respect to the tractor 1. Therefore, in this case, the ground that was 10 m horizontally ahead of the on-board camera 46 will appear in the frame as having moved higher than before it sunk, and as a result, the on-board camera 46 will capture in its frame ground that is more than 10 m in front of it, which is unnecessary for image processing.

[0081] In such a case, by slightly raising the optical axis of the on-board camera 46 and making the depression angle shallower, it is possible to fill the frame with the ground 10 m horizontally ahead of the on-board camera 46 and the scenery beyond that. Therefore, in order to adjust (fine-tune) the pitch angle of the on-board camera 46, the fixed leg 81 that attaches the on-board camera 46 to the traveling machine body can be reattached, in this case tilted slightly backward around the fulcrum bolt 82.

[0082] However, even if the pitch angle is adjusted as described above, when the driver sits in the driver's seat 18 and looks ahead, he or she cannot see the front of the bonnet 5 or the sight 8 provided in front of it, as they are hidden by the on-board camera 46 (see FIG. 1). However, the height of the on-board camera 46 is kept low enough that the driver will not notice the presence of the on-board camera 46 unless he or she is aware of it when looking down ahead, so the driver's forward visibility is not extremely impaired, and there is no adverse effect on the driver's manual steering during headland turns, for example.

[0083] However, although the protrusion of the on-board camera 46 above the bonnet 5 when viewed from the driver's seat 18 does not adversely affect headland turning, etc., it is desirable to install the on-board camera 46 low so that it is as out of sight as possible. Therefore, for example, it is conceivable to mount the on-board camera 46 at a low position by means of a mounting frame in front of the bonnet 5 that covers the driving part. However, a work vehicle having left and right front wheels 10 and rear wheels 14 such as the tractor 1 changes its direction of travel around a point (turning center) that is approximately on the extension line of the rear axle 13 when the front wheels 10, which are the steering wheels, are steered (use of the Ackermann-Jantau mechanism).

[0084] For this reason, if the on-board camera 46 is installed in front of the work vehicle far away from the rear axle 13, the camera 46 will swing widely left and right as the direction of travel changes, and since the on-board camera 46 is placed close to the ground and takes a close-up shot of the ground in front of the vehicle, which is the subject of the image, there is a risk that these effects will cause the image to be distorted. Therefore, it is desirable to install the on-board camera 46 at a position that is an appropriate distance from the rear axle 13 and not too close to the ground.

[0085] From the above viewpoint, it is considered most appropriate to set the position for capturing images of the vehicle-mounted camera 46 to a position above and toward the rear of the bonnet 5 provided at the front of the traveling vehicle body, or above and toward the front of the panel cover 28 that continues to the rear of the bonnet 5. From this viewpoint, it is also considered preferable to provide the vehicle-mounted camera 46 at the top of the interior of the cabin.

[0086] However, in this case, since the on-board camera 46 is installed above the driver's head, high off the ground, if the tractor 1 rolls left and right due to the inclination of the field, etc., the on-board camera 46 may be significantly shaken left and right, distorting the image and causing the automatic steering to become unstable. Therefore, installing the on-board camera 46 above the interior of the cabin is not entirely recommended.

[0087] On the other hand, compared to a driver sitting in the driver's seat looking up, the on-board camera 46 of this embodiment is set to a low position from which the driver sitting in the driver's seat looks down, so it can be said that the influence of left and right shaking when the tractor 1 rolls left and right is small. Then, when the on-board camera 46 is lowered from the elevated image shooting position to a retreat position close to the upper surface near the rear of the bonnet 5 or the upper surface near the front of the panel cover 28 as shown in Fig. 2(b), the driver sitting in the driver's seat 18 provided behind the panel cover 28 or steering wheel 12 can view the ground ahead and the scenery in the distance through the bonnet 5 without being obstructed by the on-board camera 46.

[0088] Therefore, the driver can manually steer the vehicle using, for example, the sight 8 protruding from the front of the bonnet 5, and drive straight ahead, follow behind, or move to a field without any hindrance in the same way as if the vehicle were not equipped with the on-board camera 46. Furthermore, regardless of whether the on-board camera 46 is in the image capturing position or the retreat position, it can be installed behind the bonnet 5 where it does not interfere with opening and closing the bonnet 5, and there is no hindrance to the work of refilling the fuel tank.

[0089] In this embodiment, the on-board camera 46 and the image processing SBC 47 are housed together in the camera cases 74, 78, but if the image processing and other functions performed by the image processing SBC 47 are assigned to the automatic steering ECU 48, the camera cases 74, 78 can be made somewhat smaller. Also, the automatic steering ECU 48 is provided using an empty space such as the top surface of the clutch housing 3, but if there is room in the main ECU of the tractor 1, which is responsible for main automatic control of lifting and lowering the work implement, etc., then the functions of the image processing SBC 47 and the automatic steering ECU 48 may be assigned to this main ECU, and the work vehicle of the present invention is not necessarily limited to the embodiment described above. [Explanation of symbols]

[0090] 1 Tractor (work vehicle) 5. Bonnet 10 Front wheel 12 Steering handle 14 Rear wheel 18 Driver's seat 22 Gate-type support frame 28 Panel cover 46 In-vehicle camera (camera module) 47 Image Processing SBC 48 Automatic steering ECU 70b Mounting arm 81 Fixed leg

Claims

1. A work vehicle equipped with an automatic steering device that drives straight or follows the work tracks of a previous process based on images taken by an on-board camera of the ground ahead and the scenery in the distance while driving for work, wherein the on-board camera is of a lift-up type and can be lowered from the image taking position, which is either above the rear of a bonnet located at the front of the running body, or above the front of a panel cover continuing to the rear of the bonnet, to a retracted position close to the upper surface of the rear of the bonnet, or the upper surface of the front of the panel cover, so that a driver sitting in the driver's seat located behind the panel cover or steering wheel can view the ground ahead and the scenery in the distance through the bonnet without being obstructed by the on-board camera.

2. A work vehicle as described in claim 1, in which a fixed leg is erected on the upper part of a gate-shaped support frame erected on the running body, and an attachment arm extending from the vehicle-mounted camera is freely fitted into this fixed leg to form a lifting mechanism for the vehicle-mounted camera, while the lifting mechanism is provided with a guide means for regulating the extension range of the attachment arm to guide the vehicle-mounted camera to an image shooting position and a retracted position, and a fixing means for disabling extension of the attachment arm to hold the vehicle-mounted camera at the image shooting position or the retracted position.

3. 3. A work vehicle as described in claim 2, wherein a fixed leg is attached to the upper part of the gate-shaped support frame using a fulcrum bolt in the left-right direction, and the pitch angle of the vehicle-mounted camera can be freely adjusted by rotating the fixed leg back and forth around the fulcrum bolt.

Images