Chemical spray vehicle

Abstract

To provide a chemical spraying vehicle capable of automatically controlling a steering mode on the basis of simple control irrespective of a steering operation, and thereby improving workability in chemical spraying.SOLUTION: A chemical spraying vehicle 1 includes: a steering mode switching mechanism 42 for switching steering modes of a vehicle 2 at least into a 2 WS mode and a 4 WS mode; a steering change-over switch 22 for an operator to select and operate the steering mode in the steering mode switching mechanism 42; a spraying part 50 for spraying chemicals in a farm field F; and a control part 30 for controlling the steering mode switching mechanism 42 to change over the steering modes in the vehicle 2 on the basis of a chemical spraying state in the spraying part 50 and an operation state in the steering change-over switch 22.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a pesticide spraying vehicle, such as a boom sprayer. [Background technology]

[0002] Conventionally, as described in Patent Document 1, a pest control device (riding management machine) is known that has a central boom and a pair of left and right booms, and sprays a pesticide solution from spray nozzles attached to these booms. In this device, the steering mode can be set to any one of the front wheel steering mode, rear wheel steering mode, and front and rear wheel reverse phase steering mode. When the boom is expanded and pesticide spraying is possible, the steering mode is forcibly shifted to the front wheel steering mode, and when the left and right booms are stored and pesticide spraying is not possible, the steering mode is shifted to the front and rear wheel reverse phase steering mode. In addition, even during turning, if the neutral switch is pressed on the radio control transmitter or if straight driving is confirmed by the operator's operation, the steering mode is shifted to the front wheel steering mode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-108609 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional device, the steering operation by the operator and the steering operation of the neutral switch, right switch, or left switch on the radio-controlled transmitter are linked to the steering mode. Therefore, the control of the steering mode becomes complicated. The operator of the radio-controlled vehicle and the worker must pay attention to the steering operation.

[0005] Therefore, the present invention aims to provide a pesticide spraying vehicle that can automatically control the steering mode based on simple control regardless of steering operation, thereby improving operability when spraying pesticides. [Means for solving the problem]

[0006] A pesticide spraying vehicle (1) according to one embodiment of the present invention is provided on a vehicle (2) traveling in a field (F) and comprises a steering mode switching mechanism (42) capable of switching the steering mode of the vehicle (2) between at least a 2WS mode and a 4WS mode, a steering switching operation unit (22) which enables an operator to select and operate the steering mode in the steering mode switching mechanism (42), a spraying unit (50) attached to the vehicle (2) for spraying pesticide in the field (F), and a control unit (30) which controls the steering mode switching mechanism (42) to switch the steering mode in the vehicle (2) based on the spraying state of the pesticide in the spraying unit (50) and the operation state of the steering switching operation unit (22).

[0007] According to this pesticide spraying vehicle (1), the operator operates the steering switch operation unit (22) to select one of the steering modes. Then, the control unit (30) controls the switching of the steering mode based on the operation state and the spraying state of the pesticide. The control unit (30) performs driving control such as 2WS mode or 4WS mode based on which steering mode is selected, regardless of the steering operation of the vehicle (2) by the operator, and the spraying state of the pesticide is taken into consideration in this driving control. For example, it is possible to control the driving in 2WS mode when the pesticide is sprayed, or in 4WS mode when the pesticide is not sprayed (pesticide spraying is stopped). Therefore, in this pesticide spraying vehicle (1), the steering mode can be automatically controlled based on simple control regardless of the steering operation. The hassle of operation for the operator is reduced, and therefore the workability during pesticide spraying is improved.

[0008] In the pesticide spraying vehicle (1), when the control unit (30) determines that the spraying state is a state in which the pesticide is sprayed in the spraying unit (50) and that the operation state is a state in which the 4WS mode is selected in the steering switching operation unit (22), the control unit (30) may control the steering mode switching mechanism (42) to switch the steering mode to the 2WS mode. In this case, even when the 4WS mode is selected in the steering switching operation unit (22), the control unit (30) performs driving control in the 2WS mode. This ensures the straight-line running ability (straight-line running stability) of the vehicle (2) during pesticide spraying. The operator does not need to be concerned about the selection of the steering mode, and only needs to pay attention to the on / off of spraying. This improves operability.

[0009] In the pesticide spraying vehicle (1), when the control unit (30) controls the steering mode switching mechanism (42) to switch the steering mode to the 2WS mode even though the 4WS mode is selected in the steering switching operation unit (22), the operation state of the steering switching operation unit (22) may be maintained with the 4WS mode selected. With this control, even if the spraying state changes, there is no need to operate the steering switching operation unit (22). In other words, the travel control by the control unit (30) takes precedence over the operation state of the steering switching operation unit (22), thereby further improving operability.

[0010] In the pesticide spraying vehicle (1), when the control unit (30) determines that the spraying state is a state in which pesticide spraying is stopped in the spraying unit (50) and that the operation state is a state in which the 4WS mode is selected in the steering switch operation unit (22), the control unit (30) may control the steering mode switching mechanism (42) to switch the steering mode to the 4WS mode. In this case, when spraying is stopped, travel control is performed in the 4WS mode, which has excellent maneuverability. For example, this is efficient for making turns on the headland. In addition, spraying work on the adjacent furrows can be started quickly.

[0011] The pesticide spraying vehicle (1) may further include a cancel operation unit (21) for allowing an operator to disable the steering mode switching control based on the spraying state and the operation state in the control unit (30). In this case, the steering mode switching control (automatic switching function) can be quickly canceled in an emergency, etc.

[0012] In the pesticide spraying vehicle (1), the control unit (30) may enable steering mode switching control based on the spraying state and the operation state only while the vehicle (2) is traveling through a field (F) where pesticide spraying is required. In this case, since the steering mode switching control (automatic switching function) is not enabled when moving between fields (F), for example, the vehicle (2) can be caused to travel in 2WS mode between fields (F). Effect of the Invention

[0013] According to the present invention, the steering mode can be automatically controlled based on simple control, regardless of the steering operation. This reduces the hassle of the operation for the operator, thereby improving the operability during spraying of the pesticide. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing a boom sprayer according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of switches provided on an operation panel of a vehicle. [Diagram 3] FIG. 2 is a functional block diagram of a drug spraying vehicle. [Figure 4] This is a plan view showing the state in which a pesticide spraying vehicle performs spraying work while traveling on a ridge. [Diagram 5] FIG. 4 is a flowchart showing a processing procedure in a control unit. [Figure 6] FIG. 6(a) is a diagram showing the area around the steering changeover switch while the pesticide is being sprayed, and FIG. 6(b) is a diagram showing the area around the steering changeover switch while the pesticide spray has been stopped and the vehicle is turning. [Figure 7] Following Figure 4, this is a plan view showing the state in which the pesticide spraying vehicle has stopped spraying pesticides and is circling the headland. [Figure 8] Continuing from Figure 7, this is a plan view showing the state in which the pesticide spraying vehicle is performing spraying work while traveling on an adjacent ridge. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] First, with reference to Figs. 1 to 3, a basic configuration of the boom sprayer 1 of this embodiment will be described. The boom sprayer 1 is a self-propelled riding management machine (chemical spraying vehicle) that sprays a chemical solution on crops, for example, in a field F (see Fig. 4, etc.). As shown in Fig. 1, the boom sprayer 1 includes a vehicle 2 that travels in the field F and a boom device 4 attached to the front of the vehicle 2. The boom device 4 includes a center boom (boom) 5 supported on the vehicle 2 via a lifting device 13, and a pair of side booms (booms) 6, 6 connected to both ends of the center boom 5. The center boom 5 and the side boom 6 are provided with a plurality of spray nozzles 10 that spray chemical solutions. When chemical solution spraying is performed, the side boom 6 is spread so as to be in a straight line with the center boom 5. When chemical solution spraying is not performed, the side boom 6 is stored in a folded state. Each side boom 6 is made of a multi-stage boom member and may be configured to be extendable and retractable.

[0017] A cabin 7 that forms a space in which an operator sits is provided at the front of the vehicle 2. An engine room 8 that houses an engine is provided at the rear of the vehicle 2. A chemical liquid tank 9 that contains the chemical liquid to be sprayed from the center boom 5 and the side boom 6 is provided between the cabin 7 and the engine room 8. The vehicle 2 includes a pair of front wheels 11 and a pair of rear wheels 12.

[0018] The boom sprayer 1 includes a traveling section 40 that drives the vehicle 2, and a spraying section 50 that sprays (sprays) the chemical solution from the spray nozzle 10 of the boom device 4 toward the field F. The traveling section 40 and the spraying section 50 are provided on the vehicle 2. A known configuration may be adopted as the configuration of the traveling section 40, but an example will be described below. In the boom sprayer 1, the power required for the chemical solution pump 51 of the spraying section 50 to spray the chemical solution and for the vehicle 2 to travel is provided by the power of an engine (not shown). The vehicle 2 is provided with a hydrostatic transmission (also called HST) for transmitting the power of the engine, and the engine power is converted into hydraulic power by the HST to supply rotational driving force to the front wheels 11 and the rear wheels 12.

[0019] The traveling unit 40 has a traveling wheel drive unit 41 that drives the front wheels 11 and / or the rear wheels 12, and a steering mode switching mechanism 42 that switches the steering mode in the traveling wheel drive unit 41. The traveling wheel drive unit 41 includes the above-mentioned HST, a speed reducer, and other power transmission systems (none of which are shown). The traveling wheel drive unit 41 may adopt a two-wheel drive system that drives either the front wheels 11 or the rear wheels 12, or a four-wheel drive system that drives both the front wheels 11 and the rear wheels 12. Alternatively, the two-wheel drive system and the four-wheel drive system may be switchable.

[0020] The traveling unit 40 is capable of switching between a 2WS mode and a 4WS mode. The steering mode switching mechanism 42 is capable of switching the steering mode of the vehicle 2 between the 2WS mode and the 4WS mode. A known configuration may be adopted as the steering mode switching mechanism 42. The steering mode switching mechanism 42 changes the steering angles of the front wheels 11 and the rear wheels 12 in response to the operation of the handlebars 15 (see FIG. 3) by the operator. More specifically, the steering mode switching mechanism 42 has, for example, front and rear hydraulic cylinders (not shown) that are driven in conjunction with the operation of the handlebars 15. In the steering mode switching mechanism 42, when the handlebars 15 are operated, the front and rear hydraulic cylinders each expand and contract, and the steering angles of the front wheels 11 and the rear wheels 12 are changed by this expansion and contraction. The 4WS mode realized by the steering mode switching mechanism 42 may be an opposite phase type or an in-phase type.

[0021] The spraying unit 50 has a piping system (not shown) such as a liquid supply pipe connecting the chemical tank 9 and the spray nozzle 10, a chemical pump 51 provided in the vehicle 2, and a chemical piping valve 52 provided in the piping for opening and closing the flow path of the chemical liquid. The chemical pump 51 also operates using the power of the engine. The spraying unit 50 is controlled by the spray control unit 33 of the control unit 30 to spray the chemical liquid on the field F.

[0022] As shown in Figs. 2 and 3, the boom sprayer 1 has an operation panel 20 provided in the cabin 7 in front of the driver's seat where the operator sits. The operation panel 20 includes several switches arranged, for example, on the side of the handle 15. The switches are arranged in a position within reach of the operator sitting in the driver's seat. The operation panel 20 includes a steering mode automatic changeover function switch (cancel operation unit) 21 for turning on and off an automatic steering mode changeover function described later, a steering changeover switch (steering changeover operation unit) 22 for controlling the steering mode changeover mechanism 42 of the traveling unit 40 to change between the 2WS mode and the 4WS mode, and a spray switch 23 for controlling the spraying unit 50 to turn on and off the spraying of the chemical solution. As shown in Fig. 2, the steering mode automatic changeover function switch 21, the steering changeover switch 22, and the spraying switch 23 are each a toggle switch or a rocker switch, etc., which are easy to operate by the operator. However, the type of these switches is not particularly limited, and known types of switches such as slide switches or button switches can be used.

[0023] An operator can activate steering mode switching control, which will be described later, by turning on the steering mode automatic switching function switch 21. While the steering mode switching control is activated, a steering mode switching control unit 32 of the control unit 30 executes its own travel control for the traveling unit 40. An operator can disable the steering mode switching control by turning off the steering mode automatic switching function switch 21. The boom sprayer 1 includes a control unit 30 that automatically switches the steering mode in the vehicle 2 to enable the steering mode switching control. The control unit 30 is provided, for example, in the cabin 7 or in the vicinity of the cabin 7. The control unit 30 has a determination unit 31, a steering mode switching control unit 32, and a spraying control unit 33.

[0024] When the operator turns on the spray switch 23, the chemical liquid piping valve 52 is opened and the chemical liquid is sprayed (sprayed) from the spray nozzle 10 on the center boom 5 and the side boom 6. When the operator turns off the spray switch 23, the chemical liquid piping valve 52 is closed and the spraying (spraying) of the chemical liquid is stopped. The chemical liquid pump 51 is operated by operating a separate switch. When the chemical liquid pump 51 is operated, the chemical liquid in the chemical liquid tank 9 is agitated and the chemical liquid is pressure-fed toward the spray nozzle 10. The side boom 6 may be opened and closed in conjunction with the operation of the spray switch 23.

[0025] The operator selects and operates the steering mode using the steering changeover switch 22. When the operator selects the 2WS mode as the steering mode (for example, by turning the steering changeover switch 22 to the left as shown in FIG. 2), the steering mode changeover mechanism 42 is basically controlled by the steering mode changeover control unit 32 of the control unit 30, and the vehicle 2 is controlled to travel in the 2WS mode. When the operator selects the 4WS mode as the steering mode (for example, by turning the steering changeover switch 22 to the right in the opposite direction to that shown in FIG. 2), the steering mode changeover mechanism 42 is basically controlled by the steering mode changeover control unit 32 of the control unit 30, and the vehicle 2 is controlled to travel in the 4WS mode. In this embodiment, the steering mode changeover control unit 32 controls the switching of the steering mode in the vehicle 2 based not only on the operation state of the steering changeover switch 22 (the selection state of which steering mode is selected) but also on the spraying state of the chemical solution in the spraying unit 50 in addition to the operation state.

[0026] The control unit 30 is a computer including a processor such as a CPU, and a ROM and a RAM which are storage devices. The control unit 30 is electrically connected to the switches of the operation panel 20, and can execute a predetermined control corresponding to the operation state of the switches. Hereinafter, the travel control in the control unit 30 of the boom sprayer 1 will be described with reference to each figure from FIG. 3 onwards. FIG. 4 is a plan view showing a state in which the boom sprayer 1 performs a spraying operation while traveling in a spraying area F1 in a farm field F. FIG. 5 is a flow diagram showing a processing procedure in the control unit 30. As shown in FIG. 4, the boom sprayer 1 enters the ridge portion F1a of the spraying area F1 with the side boom 6 deployed. At this time, the steering mode automatic switching function switch 21 of the operation panel 20 is turned on by the operator. In addition, for example, the 2WS mode is selected in the steering changeover switch 22. It should be noted that the 4WS mode may be selected in the steering changeover switch 22.

[0027] As shown in FIG. 5, first, the judgment unit 31 of the control unit 30 judges whether the steering mode automatic switching function switch 21 is on or not (step S10). If the steering mode automatic switching function switch 21 is off, the judgment process of step S10 proceeds to NO, and the control unit 30 executes steering control (step S20). In normal steering control, the steering mode switching control unit 32 performs switching control of the steering mode based only on the operation state of the steering switching switch 22. If the steering mode automatic switching function switch 21 is on, the judgment process of step S10 proceeds to YES, and the judgment unit 31 judges whether the 2WS mode or the 4WS mode is selected by the steering switching switch 22 (step S11). If the 2WS mode is selected by the steering switching switch 22, the judgment process of step S11 proceeds to 2WS, and the steering mode switching control unit 32 executes driving control in the 2WS mode (step S12).

[0028] When the 4WS mode is selected by the steering changeover switch 22, the judgment process of step S11 proceeds to 4WS, and the judgment unit 31 judges whether the spray switch 23 is on or not (step S13). When the spray switch 23 is on, the judgment process of step S13 proceeds to YES, and the steering mode switching control unit 32 executes the driving control in the 2WS mode (step S12). When the spray switch 23 is off, the judgment process of step S13 proceeds to NO, and the steering mode switching control unit 32 executes the driving control in the 4WS mode (step S14). In a state where the vehicle 2 is located at the entrance (starting end) of the ridge F1a shown in FIG. 4, if the 4WS mode is selected by the steering changeover switch 22, when the vehicle 2 travels on the ridge F1a and the spraying-on operation is performed, the driving control in the 2WS mode is forcibly executed in step S12. This maintains straightness and stabilizes the driving of the vehicle 2.

[0029] As shown in FIG. 6(a), when the steering mode switching control unit 32 switches to the 2WS mode despite the 4WS mode being selected by the steering changeover switch 22, the 4WS mode lamp 27 disposed near the steering changeover switch 22 goes out, and the 2WS mode lamp 26 lights up. This allows the operator to recognize that driving control is being performed in the 2WS mode, but the operation state of the steering changeover switch 22 remains with the 4WS mode selected. That is, the operation state of the steering changeover switch 22 remains with the 4WS mode selected. Therefore, the electrical system (wiring system related to control) is also the same as when the 4W mode is selected. In this state, the steering mode switching control unit 32 executes forced interrupt control to execute the 2WS mode.

[0030] As the process in the control unit 30, the determination unit 31 subsequently determines whether the spraying operation has been completed (step S15). The determination unit 31 may, for example, use a GPS mounted on the vehicle 2 to detect whether the vehicle 2 is located in the field F (or whether the vehicle 2 is away from the field F, etc.) and perform the determination process of step S15. Alternatively, the determination unit 31 may store the driving pattern of the vehicle 2 and the spraying pattern in the spraying unit 50, and may determine that the spraying operation has been completed when the spraying unit 50 has not sprayed the agent for a certain period of time. The result of the state determination of whether the spraying switch 23 is off (or on) may be used to determine whether the spraying operation has been completed. When the determination unit 31 determines that the spraying operation has been completed (step S15; YES), the control in the control unit 30 is terminated. When the determination unit 31 determines that the spraying operation is continuing (step S15; NO), the process returns to the determination in step S10.

[0031] Next, when the vehicle 2 finishes the spraying work in the ridge F1a and reaches the end point of the ridge F1a as shown in FIG. 4, the worker turns off the spraying switch 23. In this case, the process proceeds to step S14, and the driving control in the 4WS mode is executed. Therefore, as shown in FIG. 7, while the vehicle 2 is traveling in the headland area F2, the vehicle 2 can travel with small turning radius in the 4WS mode. Although the vehicle 2 was traveling in the ridge F1a in the 2WS mode, the worker only needs to turn off the spraying switch 23, and the driving control in the 4WS mode is automatically executed. As shown in FIG. 6(b), when the steering mode switching mechanism 42 returns the driving control to the 4WS mode, the 4WS mode lamp 27 arranged near the steering changeover switch 22 is turned on. This allows the worker to recognize that the driving control in the 4WS mode is being performed.

[0032] Incidentally, if the 2WS mode is selected by the steering changeover switch 22 in the spraying state shown in Figure 4, the operator can operate the steering changeover switch 22 in the state shown in Figure 7 to select the 4WS mode.

[0033] Furthermore, if the vehicle 2 is located at the entrance (starting point) of the adjacent ridge F1b shown in Fig. 8 and the 4WS mode is selected by the steering changeover switch 22, when the vehicle 2 travels along the ridge F1b and the spraying ON operation is performed, the vehicle 2 is forcibly controlled in the 2WS mode in step S12. This again maintains straightness and stabilizes the vehicle 2's travel. The display of the 2WS mode lamp 26 and the 4WS mode lamp 27 is controlled by the control unit 30 to change to the state shown in Fig. 6(a) (the state where the opposite side of the switch is lit). The vehicle 2 was traveling in the 4WS mode in the headland area F2, but the operator only needs to turn on the spraying switch 23, and the vehicle 2 is automatically controlled in the 2WS mode.

[0034] According to the boom sprayer 1 of this embodiment, the operator operates the steering changeover switch 22 to select one of the steering modes. Then, the control unit 30 controls the switching of the steering mode based on the operation state and the spraying state of the pesticide. The control unit 30 performs driving control such as 2WS mode or 4WS mode based on which steering mode is selected, regardless of the steering operation of the vehicle 2 by the operator, but the spraying state of the pesticide is taken into account in this driving control. For example, it is possible to control the driving in 2WS mode when the pesticide is sprayed, or in 4WS mode when the pesticide is not sprayed (pesticide spraying is stopped). Therefore, in this boom sprayer 1, the steering mode can be automatically controlled based on simple control regardless of the steering operation. The hassle of operation for the operator is reduced, and therefore the workability during pesticide spraying is improved.

[0035] In the boom sprayer 1, when the control unit 30 judges that the spraying state is a state in which the pesticide is sprayed in the spraying unit 50 and that the operating state is a state in which the 4WS mode is selected in the steering changeover switch 22, it controls the steering mode switching mechanism 42 to switch the steering mode to the 2WS mode (see step S12 in FIG. 5). Therefore, even when the 4WS mode is selected in the steering changeover switch 22, the control unit 30 performs driving control in the 2WS mode (see FIG. 6(a)). This ensures straight-line running and straight-line running stability of the vehicle 2 when spraying pesticide. The operator does not need to be concerned about selecting the steering mode, and only needs to pay attention to turning spraying on and off. This improves workability.

[0036] In the boom sprayer 1, when the control unit 30 controls the steering mode switching mechanism 42 to switch the steering mode to the 2WS mode even though the 4WS mode is selected in the steering switch 22, the operation state of the steering switch 22 is maintained in the selected 4WS mode. With this control, even if the spraying state changes, there is no need to operate the steering switch 22. In other words, the travel control by the control unit 30 takes precedence over the operation state of the steering switch 22, further improving workability.

[0037] In the boom sprayer 1, when the control unit 30 determines that the spraying state is a state in which chemical spraying is stopped in the spraying unit 50 and that the operation state is a state in which the 4WS mode is selected in the steering changeover switch 22, it controls the steering mode changeover mechanism 42 to change the steering mode to the 4WS mode (see step S14 in FIG. 5). Therefore, when spraying is stopped, travel control is performed in the 4WS mode, which has excellent maneuverability. For example, this is efficient for turning in the headland area F2 (see FIG. 7). In addition, spraying work in the adjacent ridge F1b can be started quickly.

[0038] The boom sprayer 1 further includes an automatic steering mode changeover function switch 21 that allows an operator to disable the steering mode changeover control based on the spraying state and the operation state in the control unit 30. In this case, the operator can quickly cancel the automatic steering mode changeover control changeover function in an emergency, etc., by turning off the automatic steering mode changeover function switch 21.

[0039] In the boom sprayer 1, the control unit 30 enables the steering mode switching control based on the spraying state and the operation state only while the vehicle 2 is traveling in a field F where spraying of a chemical is required (see steps S10 to S20 in FIG. 5). In this case, since the automatic switching function for steering mode switching control is not enabled when moving between fields F, for example, the vehicle 2 can be caused to travel between fields F in 2WS mode.

[0040] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, when the spraying state is determined to be on, the operation state of the steering changeover switch 22 may be changed to a state that selects the 2WS mode as the driving control is performed in the 2WS mode. The automatic steering mode changeover function switch 21 may be omitted. During the spraying operation, i.e., while the vehicle 2 is traveling in the field F, the above steering mode changeover control may be performed automatically.

[0041] In the above embodiment, it is determined whether the spray switch 23 is on in step S13, but this is not limited to the above. The spray state may be determined based on whether the chemical solution (chemical) is actually sprayed from the spray nozzle 10. For example, the open / close state of the chemical solution piping valve 52 may be detected.

[0042] The present invention can be applied to a chemical spraying vehicle other than a boom sprayer as long as the chemical spraying vehicle is equipped with multiple spray nozzles, for example, a speed sprayer, etc. The chemical sprayed by the chemical spraying vehicle is not limited to a chemical liquid, and powder or granules may be sprayed. [Explanation of symbols]

[0043] 1...boom sprayer, 2...vehicle, 4...boom device, 5...center boom (boom), 6...side boom (boom), 20...operation panel, 21...steering mode automatic switching function switch (cancel operation section), 23...spraying switch, 22...steering switch (steering switch operation section), 30...control section, 32...steering mode switching control section, 33...spraying control section, 40...traveling section, 42...steering mode switching mechanism, 50...spraying section, F...field, F1...spraying area, F1a, F1b...ridge section, F2...headland area.

Claims

1. a steering mode switching mechanism (42) provided in a vehicle (2) traveling in a field (F) and capable of switching a steering mode of the vehicle (2) between at least a 2WS mode and a 4WS mode; a steering switching operation unit (22) for an operator to select and operate the steering mode in the steering mode switching mechanism (42); A spraying unit (50) attached to the vehicle (2) and spraying a chemical to the field (F); A drug spraying vehicle comprising a control unit (30) that controls the steering mode switching mechanism (42) to switch the steering mode in the vehicle (2) based on the spraying state of the drug in the spraying unit (50) and the operation state of the steering switching operation unit (22).

2. The pesticide spraying vehicle of claim 1, wherein when the control unit (30) determines that the spraying state is a state in which the pesticide is sprayed in the spraying unit (50) and that the operation state is a state in which 4WS mode is selected in the steering switching operation unit (22), it controls the steering mode switching mechanism (42) to switch the steering mode to 2WS mode.

3. A pesticide spraying vehicle as described in claim 2, wherein when the control unit (30) controls the steering mode switching mechanism (42) to switch the steering mode to 2WS mode even though the 4WS mode is selected in the steering switching operation unit (22), the operation state of the steering switching operation unit (22) is maintained with the 4WS mode selected.

4. A pesticide spraying vehicle as described in claim 2 or 3, wherein when the control unit (30) determines that the spraying state is a state in which the pesticide spraying is stopped in the spraying unit (50) and that the operation state is a state in which 4WS mode is selected in the steering switching operation unit (22), it controls the steering mode switching mechanism (42) to switch the steering mode to 4WS mode.

5. A pesticide spraying vehicle as described in any one of claims 1 to 4, further comprising a cancel operation unit (21) for the operator to disable the steering mode switching control based on the spraying state and the operation state in the control unit (30).

6. A pesticide spraying vehicle as described in any one of claims 1 to 5, wherein the control unit (30) enables steering mode switching control based on the spraying state and the operation state only while the vehicle (2) is traveling through the field (F) where spraying of the pesticide is required.

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