Work vehicles

Abstract

The objective is to provide a work vehicle that can automatically travel smoothly without damaging the field. [Solution] A work vehicle is equipped with a position information acquisition means that acquires the vehicle's position information from radio waves received by a GNSS receiver 102, and is configured to autonomously travel along a round-trip travel path 20 consisting of a straight-ahead path 23 and a turning path 24 that turns at a headland 14. The turning path 24 is a combination of a turning region 24r and a straight-ahead region 24s, and the setting of the straight-ahead region 24s is offset from the previous straight-ahead region 24s. Furthermore, the offset amount ε is set to be greater than or equal to the contact width of the traveling wheels.

Description

Technical Field

[0001] The present invention relates to a work vehicle such as an agricultural tractor.

Background Art

[0002] In a traveling area, among a plurality of working paths set in a first area where a working path is generated, when turning of the vehicle body is required to move from the first working path to the second working path, based on the separation distance between the first working path and the second working path and the turning radius, a traveling path including any one of a first turning path without straight-ahead and reverse travel, a second turning path without straight-ahead and with reverse travel, and a third turning path with reverse travel can be generated (see Patent Document 1).

Prior Art Documents

[0008] The invention described in claim 2 is the invention described in claim 1, wherein the offset amount ε is set to be greater than or equal to the contact width of the running wheel.

[0009] The invention described in claim 3 is the invention described in claim 1 or claim 2, further comprising a turning braking force adjustment means Z that detects the amount of wheel sinking near the starting point of the turning path 24 and adjusts the braking means during turning to a preset reference braking force B0 based on the amount of wheel sinking.

[0010] The invention described in claim 4 is that, in the invention described in claim 3, when the endpoint of the turning path 24 is offset from the field edge, the standard braking force B0 is corrected to a corrected braking force B1. [Effects of the Invention]

[0011] According to the inventions described in claims 1 and 2, by setting the straight-line region 24s of the turning path 24 to be offset, the tracks left by the wheels of the work vehicle 100 do not overlap, preventing the soil in the field from hardening and preventing an increase in workload and uneven growth. In addition, the unevenness when traveling over the headland area is reduced, preventing instability during subsequent headland work.

[0012] Furthermore, in the inventions described in claims 3 and 4, the braking strength can be appropriately set according to the soil conditions, thereby minimizing damage to the field during turning. [Brief explanation of the drawing]

[0013] [Figure 1]This is a side view of an agricultural tractor according to an embodiment of the present invention. [Figure 2] This is a block diagram of the management system according to an embodiment of the present invention. [Figure 3] This is a schematic diagram showing the positional relationship between the management terminal and multiple fields in an embodiment of the present invention. [Figure 4] This is a schematic diagram recording the outer perimeter path of a field according to an embodiment of the present invention. [Figure 5] This figure shows an example of a headland travel path and a round-trip travel path according to an embodiment of the present invention. [Figure 6] This figure shows another example of the headland travel path and the round-trip travel path according to the embodiment of the present invention. [Modes for carrying out the invention]

[0014] Preferred embodiments of the present invention will be described below with reference to the drawings.

[0015] Figure 1 is a schematic side view showing the configuration of a work vehicle 100 of a work vehicle management system according to an embodiment of the present invention. The work vehicle 100 is an agricultural vehicle capable of traveling within a reciprocating adjacent work travel range 13. An engine 105 covered by a bonnet 107 is located at the front of the vehicle body, and the rotational power of this engine 105 is transmitted to the front wheels 103 and rear wheels 104 via a plurality of transmissions to enable movement. A control unit 106 is provided behind the engine 105, and a work implement 140 capable of cultivating within the reciprocating adjacent work travel range 13 is attached to the rear of the vehicle body behind the control unit 106.

[0016] The control unit 106 is equipped with a cabin that includes a steering wheel and a cockpit operated by the operator. A GNSS receiver 102 is also installed on the cabin roof 108, which is the ceiling of the cabin, and is configured to receive radio waves from the artificial satellite 170 at predetermined time intervals to measure the position of the work vehicle 100.

[0017] At the rear of the work vehicle 100, a three-point link mechanism 145 composed of an upper top link 145a and left and right lower links 145b on the lower side is provided, and a work implement 140 is connected thereto. The work implement 140 is a tillage work implement, and is provided with tillage claws 146 for tilling the soil in the field, a rotary cover 147 covering above the tillage claws 146, and a rear cover 148 supported so as to be vertically movable at the rear of the rotary cover 147.

[0018] [[ID=X]]A work implement lifting cylinder 141 is connected to the lower link 145b of the three-point link mechanism 145 via a lift arm 142, and is configured such that the lower link 145b can be moved up and down by extending and retracting the work implement lifting cylinder 141.

[0019] Hereinafter, while the work vehicle 100 has lowered the work implement 140, traveling while tilling the soil in the reciprocating adjacent work traveling range 13 is referred to as work traveling.

[0020] FIG. 2 is a block diagram showing the configuration of a work vehicle management system 1 according to a preferred embodiment of the present invention. The work vehicle 100 includes a position information acquisition unit 301 which is a position information acquisition means for acquiring the position information of the own vehicle from the radio wave received by the GNSS receiver 102 in FIG. 1, an automatic driving ECU 302 for controlling the autonomous driving of the vehicle, and a vehicle ECU 303 for controlling the traveling of the vehicle and the operation of the work implement. The vehicle ECU 303 includes a communication unit 304 for mutually communicating with a cloud C forming a communication network, and a route calculation unit 306 for calculating a traveling route from position information and terrain information.

[0021] Therefore, the work vehicle 100 is configured to be able to transmit and store the position information of the own vehicle acquired by the position information acquisition unit 301 to the cloud C via the communication unit 304 at predetermined time intervals, and to be able to acquire the information stored in the cloud C.

[0022] Note: In the original text, there is a mistake in the line numbering in the description of the three-point link mechanism in the Japanese text. The correct line numbering should be as follows: 3点リンク機構145のロアリンク145bには、リフトアーム142を介して作業機昇降シリンダ141が接続されており、作業機昇降シリンダ141を伸縮させることによりロアリンク145bを上下させることができるように構成されている。 However, since the translation is based on the provided text, the above correction is not reflected in the translation. If the original text is corrected, the translation should be adjusted accordingly.The remote management device 200 is a portable electronic computing device and consists of a management terminal 201 that can be operated by a management user. The management terminal 201 includes a communication device 202 that can communicate with Cloud C and a terminal control unit 204 that controls the management terminal 201. Therefore, by possessing the management terminal 201, the management user can exchange information with Cloud C via the communication device 202.

[0023] In this way, since the work vehicle 100 and the remote management device 200 are configured to communicate via the cloud C, the management user can monitor the status of the work vehicle 100 and send commands to it using the remote management device 200, thereby enabling remote management of the work vehicle 100.

[0024] Cloud C is equipped with a management server 320, which stores a topographic information database 322 containing topographic information of the field and its surroundings, and a location information database 323 containing location information of the work vehicle 100. Therefore, the management user can access the management server 320 and refer to the topographic information database 322 and the location information database 323 to understand the positional relationship between the work vehicle 100 and the field.

[0025] Figure 3 is a schematic diagram showing the positional relationship between the management terminal 201 and multiple adjacent reciprocating work areas 13 in the management area 10. The management area 10 is provided with multiple adjacent reciprocating work areas 13 (A1 to An), and each adjacent reciprocating work area 13 is configured for a vehicle 100 (V1 to Vn) to perform work. Each adjacent reciprocating work area 13 is adjacent to the management passage 12, and is configured so that the work vehicle 100 can enter and exit from the entrance / exit 11.

[0026] The management terminal 201 is equipped with field identification means to identify which work vehicle 100 is working in which round-trip adjacent work travel range 13. It accesses the management server 320 via the cloud C shown in Figure 2, and compares the location information of each round-trip adjacent work travel range 13 (A1~An) stored in the terrain information database 322 with the location information of the work vehicles 100 (V1~Vn) stored in the location information database 323. This allows the management terminal to identify the work vehicles 100 located within the range where the round-trip adjacent work travel range 13 is located, and to associate work vehicle Vx (x=1,2,···,n) with the field Ax (x=1,2,···,n) in which that work vehicle Vx is working.

[0027] Here, in the management terminal 201, the terminal control unit 204 can acquire terrain information for the management passage 12 of the management area 10 and the round-trip adjacent work travel area 13 (A1~An) from the terrain information database 322 shown in Figure 2 via the cloud C using the positioning device 203. Furthermore, it is configured to calculate the route (L1~Ln) from the current position of the management terminal 201 through the management passage 12 to the entrance / exit 11 of the round-trip adjacent work travel area 13, and to calculate the travel time T (T1~Tn) to the round-trip adjacent work travel area 13 (A1~An) at a predetermined speed from the distance of these routes (L1~Ln).

[0028] Figure 4 is a schematic diagram showing the work vehicle 100 recording its movement along the headland of field H, and Figure 5 is a schematic plan view showing the work vehicle 100 moving within field H.

[0029] As shown in Figure 4, field H, surrounded by ridges 15 and demarcated by the outer shape (also called the outer perimeter) Pe formed by these ridges 15, consists of a round-trip adjacent work area 13 and a headland work area (also called the headland) 14, and is configured so that a work vehicle 100 can enter and exit the management passage 12 via an entrance / exit 11. The headland work area 14 is accessible to the work vehicle 100, and this headland work area 14 can be tilled by working along the headland work path 22 which circles the outside of the round-trip adjacent work area 13.

[0030] The work vehicle 100 is equipped with a field shape acquisition means for acquiring topographic information indicating the shape of the field. As a prerequisite, the work vehicle 100 first travels along the headland travel path 22 while measuring its current position with the position information acquisition unit 301 in Figure 2, and the route calculation unit 306 in Figure 2 connects the position information of the traveled path to create route information as the outer headland travel path 22, and calculates the area enclosed by the traveled path in the route information of the headland travel path 22 to create topographic information of the field H (field position coordinates, area, and length and width), and records this information in the topographic information database 322 via the cloud C in a topographic information recording mode. The work vehicle 100 is configured so that when the topographic information recording mode is executed, the field shape acquisition means can acquire the route information of the headland travel path 22 based on the outer perimeter Pe shape information recorded in the topographic information database 322 and the topographic information of the round-trip adjacent work travel range 13 recorded in the topographic information database 322.

[0031] In terrain information recording mode, the route information of the headland travel route 22 created by the work vehicle 100 and the terrain information of the round-trip adjacent work travel area 13 are transmitted to the management server 320 via the cloud C. The management server 320, upon receiving the route information of the headland travel route 22 and the terrain information of the round-trip adjacent work travel area 13, records this information in the terrain information database 322. As a result, the work vehicle 100 can access the management server 320 via the cloud C and obtain the route information of the headland travel route 22 and the terrain information of the round-trip adjacent work travel area 13 at any time. For example, when the engine 105 is started, the work vehicle 100 obtains the route information of the headland travel route 22 and the terrain information of the round-trip adjacent work travel area 13 using the field shape acquisition means.

[0032] Thus, because the work vehicle 100 is equipped with a terrain information recording mode, it is not necessary to survey the adjacent round-trip work travel range 13 in advance to acquire terrain information, and the effort required to have the work vehicle 100 perform work in any adjacent round-trip work travel range 13 can be reduced.

[0033] As shown in Figure 5, when the work vehicle 100 travels within the round-trip adjacent work area 13, the route calculation unit 306 shown in Figure 2 calculates a round-trip travel route 20, which is the route for traveling within the round-trip adjacent work area 13, based on the terrain information of the round-trip adjacent work area 13 and the working width w of the work vehicle 100. In order to cultivate the round-trip adjacent work area 13 evenly, it is necessary to travel straight through the round-trip adjacent work area 13 a number of times obtained by dividing the width of the round-trip adjacent work area 13 by the working width w (7 times in Figure 5). Therefore, the round-trip travel route 20 is calculated to travel back and forth across the round-trip adjacent work area 13 by a straight-ahead route 23 that travels straight across the round-trip adjacent work area 13 and a turning route 24 that exits the round-trip adjacent work area 13, turns at the headland 14, and returns to the round-trip adjacent work area 13. In other words, the route calculation unit 306 consists of a straight route calculation unit 306a and a turning route calculation unit 306b (Figure 2). Hereinafter, the points where the round-trip travel route 20 intersects with the ends of the round-trip adjacent work travel range 13 will be called field endpoints 21a (P1~P7) and 21b (Q1~Q7).

[0034] Once the round-trip travel route 20 is calculated, the work vehicle 100 is configured to autonomously travel along the round-trip travel route 20, moving back and forth from one end to the other of the adjacent round-trip work area 13, and passing through the entire field by working.

[0035] Specifically, the work vehicle 100 enters the round-trip adjacent work area 13 from a field endpoint 21a (P1 (hereinafter, starting point P1)) located at the corner of the round-trip adjacent work area 13, proceeds straight to the field endpoint 21b (Q1) at the opposite position, exits the round-trip adjacent work area 13, makes a left turn at the headland 14, and re-enters the round-trip adjacent work area 13 from the adjacent field endpoint 21b (Q2). After that, it proceeds straight to the field endpoint 21a (P2) at the opposite position, exits the round-trip adjacent work area 13, makes a right turn at the headland 14, and re-enters the round-trip adjacent work area 13 from the adjacent field endpoint 21a (P3). The work vehicle 100 repeats this process until it reaches the field endpoint 21a (Q7), thereby cultivating the entire field evenly.

[0036] As mentioned above, the round-trip travel path 20 consists of a straight-line path 23 that travels straight over the round-trip adjacent work travel range 13, and a turning path 24 that leaves the round-trip adjacent work travel range 13, turns at the headland 14, and returns to the round-trip adjacent work travel range 13. In the embodiment of the tilling operation described above, the turning path 24 is calculated so that it enters the adjacent straight-line path 23 after reaching the field edge via the straight-line path 23. However, in the case of tilling or other operations, as shown in the figure, if the width w of the implement is wide or the front and rear of the implement is long, it may not be possible to enter the work row based on the adjacent straight-line path 23, and it may enter with a gap of one or more rows.

[0037] In this case, the turning path 24 is a combination of a turning area 24r and a straight area (also called a straight path) 24s. As a result, the straight area 24s overlaps particularly in the headland portion 22 of the field. The overlapping tracks left by the wheels, i.e., the ruts, can harden the soil in the field, potentially leading to increased workload and uneven growth. Furthermore, the unevenness when traveling through the headland portion can increase, potentially making subsequent headland work unstable. Therefore, when calculating the turning path 24, the system is configured to set the current straight path 24s to be offset from the straight path 24s of the previous turning path 24.

[0038] As explained in Figure 6, when the work vehicle 100 enters the round-trip adjacent work travel range 13 from the field endpoint 21a (P1 (hereinafter, starting point P1)) located at the corner of the round-trip adjacent work travel range 13, it proceeds straight along the straight path 23 to the field endpoint 21b (Q1) located opposite. After that, it exits the round-trip adjacent work travel range 13 and turns along the turning path 24. That is, immediately after reaching the field endpoint 21b (Q1) on the straight path 23, it turns left along the turning area 24r, the straight area 24s, and the turning area 24r to the field endpoint 21b (Q4) located two columns away, and from this field endpoint 21b (Q4), it re-enters the round-trip adjacent work travel range 13. After that, the vehicle proceeds straight to the field endpoint 21a (P4) on the opposite side, and after leaving the round-trip adjacent work area 13, it makes a left turn at the headland 14 and enters the round-trip adjacent work area 13 from the field endpoint 21a (P2) separated by one row. Furthermore, it reaches the field endpoint 21b (Q2) and aims for the field endpoint 21b (Q5) separated by two rows via the turning path 24. At this time, the straight path 24s is set to be offset from the previous straight area 24s and to travel outside by an offset amount ε. This allows the work vehicle 100 to travel without following the previous wheel tracks. The turning path 24 on the field endpoint 21a side is also set so that the straight path 24s does not overlap. By repeating this travel until reaching the field endpoint 21a (Q6), the entire field can be worked on evenly.

[0039] In this way, by setting the straight section 24s of the turning path 24 to be offset, the tracks left by the wheels of the work vehicle 100 do not overlap, preventing the soil in the field from hardening and thus preventing an increase in workload and uneven growth. In addition, it reduces unevenness when traveling over the headland area, preventing instability during subsequent headland work.

[0040] Regarding the offset, the offset amount ε is set to be greater than or equal to the contact width of the front wheels 103 and rear wheels 104 of the work vehicle 100. With this configuration, the turning path 24 can be set without overlapping wheel tracks. If a crawler track system is attached to the work vehicle 100, the offset amount ε is set to be greater than or equal to the crawler installation width.

[0041] Next, we will describe the turning braking force adjustment means Z, which detects the amount of wheel sinking near the starting point of the turning path 24 and adjusts the braking force of the braking means during turning. The work vehicle 100 is equipped with braking means (not shown) on each of the left and right rear wheels 104, and is configured to reduce the turning radius by braking the brake on the inner side of the turn during turning, and this inner-side braking configuration is also adopted when setting the turning path 24. However, there is a risk of damaging the field surface by braking indiscriminately regardless of the hardness of the field. For this reason, a means is provided to measure the amount of sinking φ due to the contact of the front wheel 103 or the rear wheel 104, and the braking force is adjusted according to the magnitude of this amount of sinking φ.

[0042] The work vehicle 100 is equipped with a distance sensor 30 at the front lower part to detect ground height. The difference between the distance L0 when the amount of sinking is zero (which is set and stored in advance) and the distance L detected by the distance sensor 30 during field work is calculated to determine the amount of sinking φ (= L0 - L). The braking force B0 is adjusted according to the magnitude of this amount of sinking φ. The braking force B0 can be adjusted by adjusting the hydraulic pressure supplied to the braking means. If the braking force is set to standard for a normal amount of sinking φ, the braking force B0 can be weakened in soft ground where the amount of sinking φ is large, and slightly strengthened in hard ground where the amount of sinking φ is small, allowing for turning without disturbing the field surface.

[0043] In addition, the turning braking force adjustment means Z described above is set to adjust to a standard braking force B0 corresponding to the amount of sinking φ. However, if a deviation occurs in the position of the field endpoint Q4 as a result of implementing this turning braking force adjustment means Z at the start and end of the turning path 24, for example, from the field endpoint Q1 to Q4 in Figure 6, the standard braking force B0 is corrected to a corrected braking force B1, thereby enabling accurate arrival at the field endpoint Q4.

[0044] Next, an example of the application of the position information acquisition unit 301, which is a position information acquisition means that acquires the position information of the vehicle from radio waves received by the GNSS receiver 102, will be described. The work vehicle 100 is equipped with a GNSS (Global Navigation Satellite System), specifically a standalone positioning means X represented by GPS, and a relative positioning means Y that has high measurement accuracy, represented by RTK, for example. The standalone positioning means X is a method of determining the position by installing a receiver on the work vehicle 100 and communicating with multiple satellites, while the relative positioning means Y is a method of determining the position using two receivers: one on the work vehicle 100 and another at a known point. Normally, the work vehicle 100 performs autonomous driving using the relative positioning means Y. Incidentally, while autonomously traveling along a predetermined straight path 23 within the round-trip adjacent work travel range 13, if it becomes unable to receive a signal from a known point receiver, the straight path calculation unit 306a calculates a travel line parallel to the straight path 23, switches to the standalone positioning means X from the position where the signal was lost, and continues autonomous travel to prevent work interruption. Furthermore, once it becomes possible to receive a signal from a known point receiver, it is configured to resume autonomous travel using the relative positioning means Y, thereby continuing autonomous travel.

[0045] Furthermore, the system may be configured to brake or shut down the work vehicle 100 or its engine when it becomes impossible to receive signals from a known receiver, and to notify the operator via the management terminal 201 to prompt them to take action.

[0046] Furthermore, the system may be configured to notify the operator when it loses the ability to receive signals from known receivers, allowing the operator to choose whether to continue autonomous driving or not via the management terminal 201. Alternatively, the operator can choose not to continue and continue the work manually.

[0047] While autonomously turning along the turning path 24, if it loses the ability to receive signals from a known receiver, the system switches to the standalone positioning means X while referring to the previous turning path 24, and continues autonomous driving. Furthermore, once it regains the ability to receive signals from a known receiver, it returns to autonomous turning driving using the relative positioning means Y.

[0048] As the relative positioning means Y, in addition to RTK, there is also D-GNSS, which corrects position information by correcting errors that occurred when positioning was performed independently by the base station and the vehicle receiver. The positioning method may be switchable between these two methods, and the operator may choose to switch between them. [Explanation of Symbols]

[0049] 14 Headland 20 round-trip routes 23 Straight Route 24 Turning Path 24r turning range 24s straight line area 102 GNSS receiver 103 Front wheels (driving wheels) 104 Rear wheels (driving wheels) ε offset amount B0 Standard braking force B1 Corrected braking force Z Turning Braking Force Adjustment Means

Claims

1. A work vehicle is equipped with a position information acquisition means that acquires the position information of the vehicle from radio waves received by a GNSS receiver (102), and is configured to autonomously travel along a round-trip travel path (20) consisting of a straight path (23) and a turning path (24) that turns at a headland (14), wherein the turning path (24) is a combination of a turning area (24r) and a straight area (24s), and the setting of the straight area (24s) is offset from the previous straight area (24s).

2. The work vehicle according to claim 1, wherein the offset amount (ε) to be offset is set to be greater than or equal to the contact width of the running wheels (103, 104).

3. A work vehicle according to claim 1 or claim 2, further comprising a turning braking force adjustment means (Z) that detects the amount of wheel sinking near the starting point of the turning path (24) and adjusts the braking means during turning to a preset reference braking force (B0) based on the amount of wheel sinking.

4. The work vehicle according to claim 3, wherein when the end point of the turning path (24) is offset from the field edge, the standard braking force (B0) is corrected to a corrected braking force (B1).

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