JP7835263B2 - Work vehicles - Google Patents

Description

This invention relates to a work vehicle that performs fertilization while traveling across a field.

In recent years, amid concerns about the aging workforce and labor shortages in agriculture, the average farmland area per commercial farm in Japan has been increasing, and this trend is expected to continue. Accordingly, interest in smart agriculture, which utilizes robotic technology and ICT to achieve ultra-labor-saving and high-quality production, is growing rapidly.

Amidst these trends, in the field of agricultural work vehicles, for example, as shown in Patent Document 1 below, smarter work is being achieved by using positioning satellite systems such as GPS to operate work vehicles unmanned within the field.

Incidentally, leveling the growth of crops across an entire field has long been a challenge in preventing crop lodging and other damage. However, the environment for crop growth is not uniform within a field, and the ease with which crops grow usually differs depending on the location within the field. The larger the field area, the more likely it is that variations in growth will occur. Therefore, leveling the growth of crops across the entire field can be achieved by increasing the amount of fertilizer applied in areas where crops grow easily and decreasing it in areas where they do not. For example, as described in Patent Document 2 below, in the field of autonomous work vehicles, there is a known technology that automatically adjusts the amount of fertilizer applied by a work vehicle according to its location within the field, using information from a fertilization plan map in which target amounts of fertilizer are set for each predetermined section of the field. This fertilization plan map contains data recorded for each designated plot in the field, linking the location information of that plot with the target amount of fertilizer to be applied. Plots where crops grow easily will have lower fertilizer application rates, while plots where crops do not grow easily will have higher rates.

Using the information from this fertilization plan map, conventional work vehicles acquire their own position information at predetermined time intervals while working. This allows them to identify the section of the field they are working in and automatically control the fertilizer application device to match the target fertilizer amount associated with that section. This enables conventional work vehicles to automatically adjust the fertilizer application amount for each section of the field while automatically navigating the field.

Japanese Patent Application Publication No. 11-266608 Japanese Patent Publication No. 2021-101667

However, with conventional work vehicles, when fertilizing multiple fields, a separate fertilization map had to be prepared for each field, leading to an increased workload. This was particularly problematic when fertilizing newly developed fields that had previously been abandoned farmland, as the lack of historical data and practice made preparing a fertilization map difficult.

Furthermore, when fertilizing multiple fields, in fields where the difference in topsoil depth (i.e., the depth of the topsoil layer) is greater than usual, fertilization based on a fertilization map is not always effective. In such cases, seedlings may grow too large in areas with deeper topsoil, leading to lodging (falling over). Therefore, there is a need to flexibly adjust the method for determining fertilizer amounts for each field.

Therefore, the present invention aims to solve these problems, reduce the workload of having to prepare a separate fertilization map for each of the multiple fields, and provide a work vehicle that allows for flexible modification of the method for determining the amount of fertilizer to be applied for each field.

To achieve the above objective, the first invention is:
A work vehicle comprising a fertilizer application device and a positioning device for acquiring its own position, wherein, based on the position acquired by the positioning device, it uses a fertilizer application map in which the amount of fertilizer to be applied to each plot of field is set, acquires a target amount of fertilizer to be applied to the plot to which the vehicle's position belongs, and controls the amount of fertilizer applied by the fertilizer application device,
The system further comprises a soil information acquisition unit that acquires soil information of the field, and a control device that controls the amount of fertilizer applied by the fertilizer application device.
The aforementioned soil information acquisition unit includes a topsoil depth sensor for measuring the topsoil depth of the soil and a soil fertility sensor for measuring the soil fertility.
The system is configured to allow selection and execution of two modes: a fertilization mode that uses a fertilization map to determine the amount of fertilizer applied by the fertilization device based on the information in the fertilization map, and a soil information-based fertilization mode that uses soil information acquired from the soil information acquisition unit to determine the amount of fertilizer applied by the fertilization device.
The control device provides a work vehicle characterized by automatically switching to a soil information utilization fertilization mode when the topsoil depth measured by the topsoil depth sensor becomes equal to or greater than a set depth while the fertilization map utilization fertilization mode is being executed.

According to the first invention described above, by configuring the system to allow selection between a fertilization map-based fertilization mode and a soil information-based fertilization mode, the workload of having to prepare a separate fertilization map for each field can be reduced. Furthermore, it becomes possible to flexibly change the method for determining the amount of fertilizer applied for each field, enabling efficient fertilization. In addition, at locations with deep topsoil, the fertilization mode is automatically switched, and fertilization is performed using the soil information-based fertilization mode. As a result, fertilization can be performed at locations with deep topsoil using a method that takes the topsoil depth into account, effectively preventing lodging caused by over-growth of seedlings due to deep topsoil.

The second invention is, in the first invention described above,
The system is characterized by creating a soil information utilization fertilization map by calculating the average value of the fertilizer application amount calculated by the soil information utilization fertilization mode for each field section, and by enabling the display unit to display the information from the fertilization map and the information from the soil information utilization fertilization map.

According to the second invention described above, in addition to the effects of the first invention, the display unit is configured to display information from the fertilizer map and information from the soil information utilization fertilization map, making it useful for analyzing fertilization in multiple fields.

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The third invention is, in the first invention described above,
It is equipped with a field group information management unit that manages information about managed fields,
The aforementioned field group information management unit comprises a field group information creation unit for creating field group information, a field group analysis information creation unit for creating field group analysis information, and a field group information storage unit for storing information about managed fields.
The control device is further configured to execute a basic fertilizer application mode in which a preset basic fertilizer application amount is determined as the fertilizer application amount of the fertilizer application device.
The system includes a basic fertilizer application amount setting unit for setting the aforementioned basic fertilizer application amount,
The basic fertilizer application rate setting unit is configured such that, when an operator selects a standard field from among multiple fields included in the managed field and sets the basic fertilizer application rate, it automatically sets the rate for fields that were not selected as standard fields, based on the field group analysis information.

According to the third invention described above, in addition to the effects of the first invention described above, when setting the basic fertilizer application rate for multiple fields, even fields that were not selected as standard fields can be automatically set based on field group analysis information, thereby reducing the workload on workers and improving convenience.

According to the present invention, it is possible to provide a work vehicle that reduces the workload of having to prepare a separate fertilization map for each of multiple fields, and that allows for flexible modification of the method for determining the amount of fertilizer to be applied for each field.

Figure 1 is a left side view of a work vehicle according to an embodiment of the present invention. Figure 2 is a schematic left side view of the fertilizer application device shown in Figure 1. Figure 3 is a schematic plan view of the portable information terminal shown in Figure 1. Figure 4 is a block diagram showing the configuration of the control system for the mobile information terminal shown in Figure 3. Figure 5 is an explanatory diagram illustrating the procedure for creating information for a fertilization map. Figure 6 is an explanatory diagram illustrating the data content of the soil information utilization fertilization map. Figure 7 is a schematic plan view showing an example of a managed field. Figure 8 is an explanatory diagram illustrating the data content of field group information and field group analysis information. Figure 9 is a block diagram showing the configuration of the control system, including the control device shown in Figure 1. Figure 10 is an explanatory diagram illustrating the target travel route of the work vehicle. Figure 11 is a flowchart showing the processing flow when setting the basic fertilizer application rate. Figure 12 is a flowchart showing the flow of the automatic fertilization mode switching process.

The following describes preferred embodiments of the present invention in detail, based on the attached drawings.

First, the basic configuration of work vehicle 1 will be explained below.

<Basic configuration of work vehicles>
Figure 1 is a left side view of a work vehicle 1 according to a preferred embodiment of the present invention.

In this specification, as indicated by the arrows in Figure 1, the side of the work vehicle 1 that is in the direction of travel is referred to as the front. Unless otherwise specified, the left side of the work vehicle 1 in the direction of travel is referred to as "left," and the opposite side is referred to as "right." The work vehicle 1 is also simply referred to as the "machine."

The work vehicle 1 according to this embodiment, as an example, has the configuration of a rice transplanter. Specifically, as shown in Figure 1, its basic configuration includes a vehicle body 2 (hereinafter simply referred to as "vehicle body") that travels on the field. The vehicle body 2 is equipped with a seedling planting unit 3 for planting seedlings in the field, a fertilizer application device 4 for applying fertilizer to the field, a positioning device 5 for measuring the machine's position, a soil information acquisition unit J for acquiring soil information of the field, and a control device C for controlling various mechanisms of the work vehicle 1. Furthermore, it is equipped with a portable information terminal 6 (see Figures 3 and 5) for the operator to remotely control the work vehicle 1.

<Structure of the running vehicle>
The mobile body 2 is a mobile body that forms the main body of the work vehicle 1. This mobile body 2 comprises a main frame 2a that extends in the front-rear direction of the machine and forms the machine's frame, and a rear frame 2b that extends in the width direction and is attached to the rear end of the main frame 2a. A floor step 2c on which an operator can stand is provided on the upper part of the main frame 2a, and a control unit 7 that controls operation and a cockpit 7g on which the operator sits are provided on this floor step 2c.

Furthermore, the engine E, which is the power source for the vehicle body 2, is located below the driver's seat 7g. The power output from the engine E is transmitted to the transmission case e3 via a belt-type power transmission mechanism e1 located below the floor step 2c, through a hydrostatic continuously variable transmission (HST) e2, as shown in Figure 1.

Furthermore, the hydrostatic continuously variable transmission e2 is a mechanism in which the opening degree of the trunnion shaft (not shown) is adjusted by the drive of the HST servo motor e4 (see Figure 2), thereby changing the output to the transmission case e3. This allows for adjustment of the vehicle speed.

The power transmitted to the transmission case e3 is shifted internally and then branched and transmitted to the pair of front wheels 9 and the pair of rear wheels 10 for driving, and to the seedling planting unit 3 for work. The driving power is transmitted to the pair of front wheels 9 via the front wheel final drive case e5 and front wheel axle e6 (see Figure 1), and also to the pair of rear wheels 9 via the pair of rear wheel transmission shafts e7, the pair of rear wheel gear cases e8 and rear wheel axle 82 shown in Figure 1. Meanwhile, the work power is transmitted to a planting clutch (not shown) located at the rear of the vehicle body 2. When the planting clutch is engaged through a predetermined operation, the power is further transmitted to the seedling planting unit 3.

The control unit 7 is equipped with various operating components for the operator. Specifically, it includes a main gear lever 7a for changing the forward/reverse movement and vehicle speed of the vehicle body 2, a steering wheel 7b for steering the pair of front wheels 9, a straight-line assist lever 7c for starting or ending the straight-line control, a type of automatic driving, via the control device C, and an operation panel 7d equipped with various operation switches. Furthermore, the operation panel 7d is equipped with a monitor 7e capable of displaying various information. In addition to the steering wheel 7b, the control unit 7 also includes a steering shaft 7f, a pitman arm, and tie rods (not shown) as steering mechanisms for steering the work vehicle 1. These mechanisms change the steering angle of the front wheels 9, which are the steering wheels, in accordance with the rotational operation of the steering wheel 7b. A driver's seat 7g is located behind the steering wheel 7b.

<Structure of the seedling planting section>
The seedling planting unit 3 is attached to the rear of the vehicle body 2 via a lifting linkage device 11. The lifting linkage device 11 comprises an upper link arm 11a and a pair of left and right lower link arms 11b, and is configured to allow the seedling planting unit 3 to move up and down.

The front ends of the upper link arm 11a and the lower link arm 11b are attached to the link base frame 12, which is fixed to the rear frame 2d, while the other ends are attached to the upper and lower link arms 13 located below the seedling planting section 63.

Here, the control device C controls an electronic hydraulic valve (not shown), and when the lifting hydraulic cylinder 14 shown in Figure 1 is retracted hydraulically, the upper link arm 11a rotates upward and backward, causing the seedling planting unit 3 to rise to a non-working position. When the seedling planting unit 3 is in the non-working position, its lower end is at approximately the same height as the bottom of the main frame 2a.

In response, when the lifting hydraulic cylinder 14 is extended hydraulically, the upper link arm 11a rotates downward and backward, lowering the seedling planting unit 3 to a working position (the position shown in Figure 1) where seedling planting can be performed.

As shown in Figure 1, the seedling planting unit 3 comprises a seedling stand 3a for propping up soil-covered mat-shaped seedlings (so-called seedling mats), a planting device 3b located behind and below the seedling stand 3a, a center float 3c located below the seedling planting unit 3b, and side floats 3d positioned to the left and right of the center float 3c.

Multiple planting devices 3b are arranged in a row along the width of the work vehicle 1, and each planting device 3b is equipped with two pairs of planting tools 3e arranged in the front-to-back direction. When the planting clutch is engaged and the drive shaft 3f shown in Figure 1 is rotated, the front planting tool 3e and the rear planting tool 3e shown in Figure 1 rotate around the drive shaft 3f, alternately picking up seedlings located at the lower end of the seedling tray 3a and planting them in the field.

The center float 3c and side floats 3d are configured to glide and level the field as the work vehicle 1 moves, and seedlings are planted in the field leveled by each float 3c and 3d by each planting device 3b. Furthermore, the center float 3c and side floats 3d are configured to swing to conform to the unevenness of the field.

<Configuration of the fertilizer application system>
Figure 2 is a schematic left side view of the fertilizer application device 4 shown in Figure 1.

The fertilizer application device 4 comprises an air chamber 4a extending in the left-right direction of the machine, a blower 4b that pumps air from left to right through the air chamber 4a, a fertilizer hopper 4c for storing fertilizer to be supplied to the field, a plurality of dispensing devices 4d located below the fertilizer hopper 27, a plurality of connecting pipes 4e located below each dispensing device 4d, with their front ends connected to the air chamber 4a, and a plurality of fertilizer hoses 4f connected to the rear ends of each connecting pipe 4e and extending to the lower part of the seedling planting section 3.

The blower 4b is equipped with an intake duct 4g. When a blower motor (not shown) is driven, air is drawn in through the intake duct 4f and supplied into the air chamber 4a. The air supplied into the air chamber 4a is then pumped to the right and supplied to each fertilizer hose 4f through each connecting pipe 4e.

Each dispensing device 4d has an opening at the top to receive fertilizer supplied from the fertilizer hopper 4c, and internally contains a dispensing roll 4i with a dispensing groove 4h on its outer surface. As the dispensing shaft 4j, inserted through a hole (not shown) that penetrates each dispensing roll 4i in the left-right direction, rotates, the dispensing rolls 4i rotate. This causes the fertilizer in the dispensing groove 4h to be dispensed downwards from the dispensing device 4d. The fertilizer dispensed by the dispensing rolls 4i is supplied into the connecting pipe 4e. At this time, the fertilizer supplied into the connecting pipe 38 is supplied to the field via air supplied from the front air chamber 4a, passing through the fertilizer hose 6f.

Here, the rotation speed of the fertilizer application rate adjustment motor 4m, which rotates the dispensing shaft 4j, is controlled by the control device C. That is, since the amount of fertilizer dispensed by the dispensing device 4d is determined by the rotation speed of the dispensing roll 4i, the control device C can control the fertilizer application rate of the fertilizer application device 4 by controlling the fertilizer application rate adjustment motor 4m. More specifically, the fertilizer application rate is the weight of fertilizer supplied per unit area of the field, for example, determined by the kilograms of fertilizer supplied per 10 ares (1 are). Therefore, the control device C controls the rotation speed of the dispensing roll 4i so that it reaches a target speed calculated based on the target fertilizer application rate. The higher the target fertilizer application rate, the faster the rotation speed of the dispensing roll 4i is controlled; the lower the target fertilizer application rate, the slower the rotation speed is controlled.

<Configuration of the positioning device>
The positioning device 5 includes a GNSS receiver with a receiving antenna that receives radio waves from GNSS satellites, and an inertial measurement module that detects the tilt and acceleration of the three axes of the vehicle. This positioning device 5 is located at the front of the vehicle body 1, at the upper end of the frame material extending upward, and performs the function of acquiring the vehicle's position information. Here, position information refers to information indicating the position of the work vehicle 1, and includes at least information indicating the latitude and longitude of the vehicle. The position information measured by the positioning device 5 is transmitted to the control device C (see Figure 5).

<Configuration of the soil information acquisition unit>
The soil information acquisition unit J acquires information indicating the soil's fertility (i.e., how easily crops can grow) by measuring the soil in the field (hereinafter referred to as soil information). The soil information acquisition unit J is equipped with a topsoil depth sensor j1 that measures the topsoil depth (i.e., the depth of the topsoil layer) and a soil fertility sensor j2 that measures the soil's fertility. The topsoil depth sensor j1 is an ultrasonic sensor installed at the front of the vehicle body 2, and can measure the topsoil depth by measuring the depth to which the vehicle body sinks down to the hardpan. The soil fertility sensor j2 is installed on the front wheel 9, and can measure the soil's fertility by passing a weak electric current through the soil and measuring the ions (nutrients) in the soil from its electrical conductivity (electrical resistance). More specifically, the SFV value (Soil Fertility Value) is measured as an indicator of fertility. This SFV value is a numerical value equivalent to the EC value (Electrical Conductivity), and its unit is mS/cm (millisiemens). The measurement information (topsoil depth, SFV value) from the soil information acquisition unit J is linked to the location information (e.g., latitude, longitude) of the point measured by the positioning device 5 at predetermined time intervals and transmitted to the control device C.

<Configuration of a mobile information terminal>
Figure 3 is a schematic plan view of the portable information terminal shown in Figure 1, and Figure 4 is a block diagram showing the configuration of the control system of the portable information terminal shown in Figure 3.

The portable information terminal 6 is an information processing device separate from the vehicle body 2, and is, for example, a smartphone or tablet, an information processing device that can be carried by the operator. Although not shown in the figure, this portable information terminal 6 is configured to include a CPU for processing calculations and memory capable of reading and writing information necessary for calculations. The configuration shown as a functional block in Figure 4 is realized by the CPU operating according to various control programs stored in the memory.

As shown in Figures 3 and 4, the portable information terminal 6 comprises a display unit 6a, an operation unit 6b, an NDVI value acquisition unit 6c, a fertilization map creation unit 6d, a soil information utilization fertilization map creation unit 6e, a field information management unit 6f, and a communication control unit 6j.

The display unit 6a has the function of outputting video and audio, and is composed of, for example, a liquid crystal panel with a speaker. The operation unit 6b is composed of multiple pressure-sensitive buttons, etc. The fertilization map 6c has the function of setting the fertilization map Dh (described later) to the fertilization map storage unit 6c and the control device C. The data related to the fertilization map Dh may be configured to be acquired from an external server SV, or it may be configured to generate data based on the operation of the operation unit 6b, and the data may be set by the operator's operation of the operation unit 6b related to setting the fertilization amount.

Furthermore, the fertilization map storage unit 6d is a memory equipped with a storage area, and is composed of RAM or the like, but may also be composed of a removable recording medium such as an SD card. The fertilization map data Dh, described later, is stored in this fertilization map storage unit 6c before the start of the operation.

The NDVI value acquisition unit 6e performs the function of acquiring the NDVI value (Normalized Vegetation Index) of the field to be worked on. The NDVI value is calculated for each field location based on, for example, satellite imagery of the field before harvest in the previous year, showing the field where seedlings will be planted. The satellite imagery of the field before harvest in the previous year is acquired from an external server SV connected via a network NW. The NDVI value is represented as an integer value between 0 and 200, and a higher value is estimated to indicate higher soil fertility. Information regarding the calculated NDVI value of the field is linked to the data in the fertilization map Dh for each field location and stored in the fertilization map storage unit 6d. Thus, the data in the fertilization map Dh is configured to include information regarding the NDVI value of the field.

<Fertilization Map>
The fertilization map creation unit 6d performs the function of creating information for the fertilization map Dh. Figure 5 is an explanatory diagram illustrating the procedure for creating information for the fertilization map. Referring to Figure 5, the procedure for creating the fertilization map Dh by the fertilization map creation unit 6d will be explained below.

First, the fertilization map creation unit 6d acquires information from the NDVI value acquisition unit 6e, specifically from the NDVI value map Dn. This NDVI value map Dn is data in which an NDVI value is set for each point P in the field. It consists of at least information indicating the field area, location information for each point within the field area, and information on the NDVI value set for each point in the field. Furthermore, any point P within the roughly rectangular field area R, which represents the field area, can be identified by its latitude and longitude and corresponding two-dimensional coordinates X and Y.

Next, a conversion NDVI value map Dn2 is created to convert the information in the NDVI value map Dn into the information in the fertilization map Dh. Here, the fertilization map Dh is data in which the target fertilization amount is set for each field section, and it consists of at least information indicating the field area, location information for each point within the field area, and information on the target fertilization amount set for each field section.

In detail, as shown in Figure 5, the fertilization map Dh allows any point within the roughly rectangular field area R, which represents the field's boundaries, to be identified by its latitude and longitude, and corresponding two-dimensional coordinates X and Y. This configuration allows for the identification of points within the field area R based on the positional information indicating the latitude and longitude of the machine located within the field.

Furthermore, the field area R is divided into rectangular sections K2 of predetermined size in a matrix. The fertilization map Dh is composed of information for each section K2, including a section number to identify the section, the two-dimensional coordinate range of the section (range X, range Y), and the target fertilization amount M and NDVI value set for that section K. The target fertilization amount M is the target amount (control amount) for the fertilization device 4, and is set, for example, in kilograms of fertilizer per 10 ares (a).

With this data structure, the control device C can, by referring to the fertilization map Dh, identify the section K2 to which any point in the field being worked belongs based on its location information, obtain information on the target fertilizer application amount M set for that identified section, and control the fertilizer application amount of the fertilizer application device 4 to match the obtained target fertilizer application amount M.

Therefore, the conversion NDVI value map Dn2 is configured to divide the field area R of the NDVI value map Dn into a matrix according to the fertilization map Dh, assign a section number to each section K, calculate the average value of the NDVI values of the points included in that section, and set the average NDVI value, which is the calculated average value.

Next, a fertilization map Dh is created for each plot K by converting the average NDVI value into a target fertilizer application amount M. Here, the target fertilizer application amount M for each plot K2 is determined based on the average NDVI value of each plot K2 using a predetermined calculation method. However, the higher the average NDVI value, the more fertile the soil in that plot is estimated to be, so the target fertilizer application amount M is set lower. The target fertilizer application amount M for each plot K2 in the fertilization map Dh can be changed as needed by the operator using the portable information terminal 6. This allows for setting fertilizer application amounts that take into account soil fertility, etc., for each plot in the field. The information in the created fertilization map Dh is stored in the field group information management unit 6f, which will be described later. It is also transmitted to the control device C and stored in the information storage unit c5, which will be described later.

<Soil Information-Based Fertilization Map>
The soil information utilization fertilization map creation unit 6e performs the function of creating a soil information utilization fertilization map Dj. Figure 6 is an explanatory diagram illustrating the data content of the information in the soil information utilization fertilization map Dj. As shown in Figure 6, the soil information utilization fertilization map Dj divides the field area R into rectangular sections K3 of a predetermined size in a matrix manner, corresponding to section K2 of the fertilization map Dh. That is, the size and range of sections K2 and K3 are designed to be the same. Then, a soil information utilization fertilization amount M2 is set for each section K3.

Here, the soil information-based fertilizer application amount M2 is set by calculating the average value for each field section from the fertilizer application amount calculated by the calculation method of the soil information-based fertilizer application mode described later. In other words, the soil information-based fertilizer map creation unit 6e acquires the fertilizer application amount calculated by the calculation method of the soil information-based fertilizer application mode from the control device C at predetermined time intervals, along with location information, determines which section K3 it belongs to from the machine's location information, aggregates the fertilizer application amount for each section K3, calculates the average value, and sets the calculated average value as the soil information-based fertilizer application amount M2 for each section K3, thereby enabling the creation of the soil information-based fertilizer map Dj. The created soil information-based fertilizer map Dj is stored in the field group information management unit 6f described later. Furthermore, the portable information terminal 6 is configured so that the operator can display and compare the fertilizer map Dh and the soil information-based fertilizer map Dj stored in the field group information management unit 6f on the display unit 6a by performing predetermined operations. This allows for the comparison of fertilizer application rates calculated using different methods, which can be used to analyze the most suitable fertilization method for each field.

The field group information management unit 6f performs the function of managing information about multiple fields that are the target of work (hereinafter also referred to as "managed fields"). Note that "field group" refers to multiple fields. The field group information management unit 6f comprises a field group information creation unit 6g that creates field group information DG, a field group analysis information creation unit 6h that creates field group analysis information DA, and a field group information storage unit 6i that stores information about managed fields.

Figure 7 is a schematic plan view showing an example of a managed field, and Figure 8 is an explanatory diagram illustrating the data contents of the field group information and field group analysis information. The field group information DG created by the field group information creation unit 6g summarizes information about managed fields, and for each field, it summarizes information such as a topsoil depth map Ds, NDVI value map Dn, fertilization map Dh, soil information utilization fertilization map Dj, lodging location map Ds, basic fertilization amount, total fertilization amount, and total yield, which are mapped by summarizing the measured values obtained by the topsoil depth sensor j1 together with location information. The lodging location map Dj is a map that shows the lodging location of seedlings, and is created, for example, by image analysis of satellite images of the field before harvest in the previous year, which shows the field where seedlings will be planted. In the illustrated example, information regarding the three fields H1, H2, and H3 shown in Figure 7 is consolidated into the field group information DG shown in Figure 8.

The field group analysis information creation unit 6h creates field group analysis information DA based on the field group information DG. The created field group analysis information DA is configured to be displayed and confirmed by the operator on the display unit 6a through a predetermined operation. This allows for the analysis of fertilization methods suitable for each of multiple fields. The field group analysis information DA includes, for example, the NDVI value map average value showing the average value of the entire field in the NDVI value map Dn, the fertilization map average value showing the average value of the target fertilization amount M for the entire field in the fertilization map Dh, and fertility rank (for example, a five-level evaluation of S, A, B, C, D) indicating the evaluation of the field's fertility based on the values of the NDVI value map average value and the fertilization map average value.

The created field group information DG and field group analysis information DA are stored in the field group information storage unit 6i, and the system is configured so that the operator can display and confirm them on the display unit 6a by performing a predetermined operation. This makes it possible to analyze fertilization methods suitable for each of multiple fields. In addition, the field group analysis information DA is compiled for each field (fields H1, H2, and H3), but data combining multiple fields may also be created. For example, by creating data in which the values of fields H1, H2, and H3 are added together or the average value is calculated and recorded, it can be used to analyze the entire field (fields H1, H2, and H3). The operator may also select fields from multiple fields to calculate the sum or average value (for example, fields H1 and H3) and have the data created accordingly. This makes it easier to analyze fields in different locations (for example, multiple fields belonging to region 1 and multiple fields belonging to region 2) even when there are multiple fields located far apart.

Furthermore, the portable information terminal 6, via the communication control unit 6f, can transmit and receive various information wirelessly with the work vehicle 1 and the external server SV via the network NW. Operation information from the operation unit 6b is transmitted to the control device C of the work vehicle 1, and the control device C performs various processes according to the acquired operation information. This allows the worker to remotely control various commands and settings, such as starting work, starting to drive, forward/reverse, and stopping, without boarding the work vehicle 1, by operating the portable information terminal 6.

<Control device configuration>
Figure 9 is a block diagram showing the configuration of the control system including the control device C of the work vehicle 1.

Control device C is an information processing device composed of multiple ECUs (Electronic Control Units). Each of these ECUs is equipped with a CPU for performing calculations and memory capable of reading and writing information necessary for those calculations. The CPU operates according to various control programs stored in the memory, thereby realizing the configuration shown as a functional block in Figure 2.

As shown in Figure 5, the control device C comprises an output processing unit c1, a communication processing unit c2, an input processing unit c3, a travel control unit c4, an information storage unit c5, a travel management unit c6, a fertilizer application amount setting unit c7, and a fertilizer application device control unit c8. These units are configured to send and receive information from each other via the communication bus BA.

The output processing unit c1 functions as an input/output interface and is connected to the driving system equipment group M1, which controls driving functions such as driving, stopping, and changing the direction of travel of the work vehicle 1; the work system equipment group M2, which controls work functions such as fertilization and planting; and the monitor 7e, which outputs video and audio. For example, in this embodiment, the driving system equipment group M1 includes mechanisms such as a steering actuator, engine E, transmission, and brakes, while the work system equipment group M2 includes mechanisms such as a PTO clutch, PTO transmission, braking system, and lifting hydraulic cylinder 14.

The communication processing unit c2 is a communication mechanism that connects to an external device physically separated from the control device C via a network NW and exchanges information through communication. In this embodiment, the communication processing unit c2 is connected to, for example, a portable information terminal 6, enabling the transmission and reception of various types of information.

The input processing unit c3 is a mechanism that receives information input from connected external devices and is capable of acquiring various types of information, such as positioning information and detection information. In this embodiment, the input processing unit c3 is connected to the positioning device 5, the driving system detection sensor S1 including the steering angle detection means, the seedling planting unit 3, the fertilizer application device 4, and various sensors that detect the operating status, as well as the work system detection sensor S2 including the soil information acquisition unit J.

Furthermore, the control device C includes a travel control unit c4 that controls the movement of the work vehicle A, an information storage unit c5 that stores various information, and a route management unit c6 that performs processing related to the target travel route L.

The driving control unit c4 is a mechanism that includes a program and various circuits for controlling the movement of the work vehicle 1 during automatic driving (automatic steering) and manual driving (manual steering). It includes an automatic driving control device c41 that controls the driving system equipment group M1 during automatic driving, and a manual driving control device c42 that controls the driving system equipment group M1 during manual driving.

The automatic driving control device c41 includes a vehicle position calculation unit c411 that calculates the vehicle's position in the field based on positioning information (location information) acquired from the positioning device 5, a vehicle orientation calculation unit c412 that calculates the vehicle's orientation, a deviation calculation unit c413 that calculates the deviation, and a steering angle calculation unit c414 that calculates the steering angle from the detection information of the driving system detection sensor group S1. The automatic driving control device c41, configured in this way, calculates the deviation using the deviation calculation unit c413, calculates the appropriate steering angle of the steering wheel 7b for the work vehicle 1 to travel along the target driving path L based on the calculated deviation, and controls the steering actuator to achieve the calculated steering angle, thereby enabling the work vehicle 1 to automatically travel along the target driving path L.

The information storage unit c5 is a storage device capable of storing various types of information, and is composed of, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The information storage unit c5 includes a field information storage unit c51 for storing field information (hereinafter referred to as "field information"), a route information storage unit c52 for storing the travel route of the work vehicle 1 (hereinafter referred to as "route information"), and a work information storage unit c53 for storing setting information related to work (hereinafter referred to as "field information"). The information stored in the information storage unit c5 can be acquired by the portable information terminal 6 via the network NW, and the acquired information can be displayed on the display unit 6a for the worker. This allows the worker to analyze the field and the work.

The field information storage unit c51 is a memory area for storing field information. This field information includes, for example, information such as the size, shape, and location of the field being worked on, and the location data of the ridges that define the field's boundaries.

The route information storage unit c52 is a memory area for storing route information. Here, the route information includes, for example, position information indicating the target travel route L described later, and other information related to the travel route of the work vehicle 1.

The work information storage unit c53 is a memory area for storing work information. Here, the work information includes, for example, setting information related to the work of the work vehicle 1, such as the work width W and the type of work (fertilization, planting, etc.), which are pre-set by the worker.

The travel management unit c6 is a program that manages the travel of the work vehicle 1, and includes a route calculation unit c61, a travel order setting unit c62, and a stop position setting unit c63.

The route calculation unit c61 calculates the target travel route L based on field information and work information, etc.

Figure 10 is an explanatory diagram illustrating the target travel path of the work vehicle 1. Here, the target travel path L refers to the travel path that the work vehicle 1 aims for during automated driving. The information indicating the target travel path L includes positional information showing the trajectory of the target travel path L. The route calculation unit c61 calculates the target travel path L using, for example, the following design procedure.

First, field information is acquired, and the field area R is divided into a headland area R1 where work is performed in a circular motion, and a straight-line area R2 where work is performed in a straight line. Here, the headland area R1 is set as a frame-shaped area with a working width W, and the rectangular straight-line area R2 is set inside the headland area R1. The field area R is the area representing the field, and its shape and size are designed to correspond to the shape and size of the field.

Next, a headland travel path l1 is designed, which travels in a circular manner within the headland travel area R1 (work paths VI to IX). Subsequently, multiple straight travel paths l2 are designed, which travel in a straight line within the straight travel area R2 (work paths I to V). Here, to prevent overlapping work at a single point, the straight travel paths l2 are spaced approximately equal to the work width W.

Next, a non-working path l3 is designed, which involves moving along two straight-line travel paths l2 in a single continuous line, as well as turning along two straight-line travel paths l2 and moving from a straight-line travel path l2 to a headland travel path l1, without performing any work. The information indicating the target travel path L calculated in this manner is stored in the path information storage unit c52.

The travel order setting unit c62 acquires information indicating the target travel route L calculated by the route calculation unit c61, and sets the travel order of the work routes (work routes I to IX in the illustrated example), which are the routes for performing tasks included in the target travel route L. This travel order is set based on predetermined rules, but the operator can also change it to any desired travel order by operating the portable information terminal 6 or the control panel 7d. This travel order setting information, along with the information indicating the target travel route L, is stored in the route information storage unit c52.

For example, in the example shown in Figure 10, the travel order is set as follows: work path I, work path II, work path III, work path IV, work path V, work path VI, work path VII, work path VIII, and work path IX. The direction of the arrows for the headland travel path l1 and straight travel path l2 shown in the figure indicates the direction of travel of the work vehicle 1, but depending on the travel order, it is not necessarily limited to this direction. When the automatic travel of the work vehicle 1 begins, the work vehicle 1 is moved to the vicinity of the work start point Ps. This movement is performed by the operator, but the work vehicle 1 may be driven automatically based on the position information of the work start point Ps. Furthermore, when the work vehicle 1 reaches the work end point PE of the straight travel path l2 in Figure 6, it is configured to travel via the non-work path l3 and then from the straight travel path l2 to the headland travel path l1. However, depending on the travel order, it can also be configured to travel in the reverse direction, from the headland travel path l1 to the straight travel path l2.

The stop position setting unit c63 sets the position where the work vehicle 1 will temporarily stop during automatic travel along the target travel path L. While these stop positions are set based on predetermined rules, the operator can also change the set stop positions by operating the portable information terminal 6 or the control panel 7d. Information regarding the set stop positions is stored in the route information storage unit c52. When the work vehicle 1 reaches a stop position during automatic travel, it temporarily stops automatic travel. After the temporary stop, the system is configured to resume automatic travel by instructing the operator to resume travel through a predetermined operation on the portable information terminal 6. This allows the operator to check the remaining fuel, fertilizer, seedlings, etc., in the work vehicle 1 at the stop position and replenish materials if necessary.

The stopping position can be set at the end points of work paths I through IX. In the illustrated example, it is set at the end points Pm1 and Pm2 of work paths II and IV on one end of the field (i.e., the side easily visible to the worker). Alternatively, it may be set at the end points of work paths I, III, and V on the other end of the field.

Furthermore, the stop position setting unit c63 is configured to skip the set stop position (continue automatic driving without stopping) when a predetermined operation is performed on the portable information terminal 6 while the work vehicle 1 is automatically driving. The number of skips can be accumulated and reserved before reaching the stop position, and this number of skips is stored in the work information storage unit c53 each time. For example, pressing the "F" button and the "Right" and "OK" buttons simultaneously on the operation unit 6b can increase the number of stop position skips by one. Furthermore, pressing the "F" button and the "Left" and "Back" buttons simultaneously on the operation unit 6b can decrease the number of stop position skips by one. This allows for flexible adjustment of the number of stops for material replenishment, for example, depending on the size of the field.

The fertilizer application amount setting unit c7 is a program that performs the function of setting the fertilizer application amount, and includes a basic fertilizer application amount setting unit c71 and a soil information learning unit c72.

The basic fertilizer application rate setting unit c71 is a program that performs the function of setting the basic fertilizer application rate. This basic fertilizer application rate can be set by operating the portable information terminal 6 or the control panel 7d. The set value of the basic fertilizer application rate is stored in the work information storage unit c53 and referenced as needed during fertilization work. Here, the basic fertilizer application rate is the basic fertilizer application rate for the field being worked on; in other words, it is the basic value of the fertilizer application rate set for each field. The basic fertilizer application rate is set, for example, in kilograms of fertilizer per 10 ares (a).

<Setting the basic fertilizer application rate>
Figure 11 is a flowchart showing the processing flow when setting the basic fertilizer application rate.

The basic fertilizer application rate setting unit c71 allows for the simultaneous setting of basic fertilizer application rates for multiple fields (managed fields) using the following procedure.

As shown in Figure 1, first, a field to be set (standard field) is selected from the managed fields (Step #1). Once a standard field is selected (for example, field H1 in Figure 7), a reference fertilizer application rate, which is used as a reference when setting the basic fertilizer application rate, is displayed on the display unit 6e or monitor 7e (Step #2). The reference fertilizer application rate is, for example, the average value of the fertilizer map included in the field group analysis information DA of the field selected as the standard field (for example, in Figure 8, 35 kg/10a).

Next, when the operator inputs the basic fertilizer application rate for a standard field, this is set in the field information storage unit c51. Furthermore, based on the input information regarding the basic fertilizer application rate, the data content of the basic fertilizer application rate item in the field group information storage unit 6i's field group information DG is also updated (step #3).

Next, based on the standard fertilizer application rate set in the input settings for the standard field, candidate basic fertilizer application rates for fields other than the standard field (for example, fields H1 and H2 in Figure 7) are calculated (Step #4). The candidate basic fertilizer application rates calculated at this time are determined, for example, by comparing the average values of the NDVI value maps in the field group analysis information DA. In the example in Figure 8, the basic fertilizer application rate for standard field H1 is input as 40, the average value of the NDVI value map for field H1 is 120, and for field H2 it is 100. Therefore, the candidate basic fertilizer application rate for field H2 is calculated as 40 × 120 / 100 = 48. Note that the calculation method is not limited to this. Candidate basic fertilizer application rates for field H3 are calculated in a similar manner.

Next, the basic fertilizer application rate setting unit c71 determines whether the calculated candidate basic fertilizer application rate falls within the range between the set upper and lower limits (step #5). These upper and lower limits are set by the operator; for example, the upper limit might be set to 80 kg/10a and the lower limit to 30 kg/10a.

The basic fertilizer application rate setting unit c71, if it determines that the calculated candidate basic fertilizer application rate is outside the range between the set upper and lower limits (N in step #5), corrects the candidate so that it falls within the range (step #6). For example, if the candidate basic fertilizer application rate exceeds the set upper limit of 80, it is corrected to 80; if it falls below the set lower limit of 30, it is corrected to 30. At this time, for reference, the value before correction is also displayed on the display unit 6e or monitor 7e so that the operator can confirm it. This prevents the setting of a basic fertilizer application rate value that deviates from the appropriate range.

Finally, the basic fertilizer application rate setting unit c71 sets the calculated candidate basic fertilizer application rate (when Y is selected in step #5) or the modified candidate basic fertilizer application rate (when N is selected in step #5) as the basic fertilizer application rate for each field other than the standard field (fields H2 and H3) in the information storage unit c51. Furthermore, based on the information regarding the set basic fertilizer application rates, the data content of the basic fertilizer application rate item in the field group information storage unit 6i's field group information DG is also updated (step #3). With this configuration, when managing multiple fields, the effort of setting the basic fertilizer application rate for each field is eliminated, reducing the workload on the operator and improving convenience, while also enabling the setting of appropriate basic fertilizer application rates.

<Learning about soil information (teaching)>
The soil information learning unit c72 is a program that performs the function of learning (teaching) soil information. The soil information learning unit c72 manages the start and end of soil information learning and stores the soil information (topsoil depth, SFV value) acquired from the soil information acquisition unit J during learning in the work information storage unit c53. Furthermore, whenever soil information (topsoil depth, SFV value) is acquired, it calculates a growth evaluation value W using the topsoil depth and SFV value and stores it in the work information storage unit c53. Here, the growth evaluation value W indicates an evaluation value of how easily seedlings can grow in the soil, and a larger value indicates easier growth.

The growth evaluation value W can be calculated, for example, by the following formula (1).

(Equation 1) W = α × SFV value + β × topsoil depth, where α and β are weighting coefficients. As a result, the growth evaluation value W increases as the SFV value increases and as the topsoil depth increases.

The soil information learning unit c72 begins learning soil information when the pre-set start conditions are met, and terminates learning soil information when the pre-set end conditions are met. The start and end conditions for soil information learning are pre-set and stored in the work information storage unit c53, but the operator can change these settings using the portable information terminal 6 or the control panel 7d.

The conditions for starting soil information learning can, for example, be that automatic driving has begun. Alternatively, it can be that the system has reached the starting point of one of the work routes I through IX (which can be selected and set by the operator) on the target driving path L (see Figure 6). Furthermore, it can be that the system has reached the starting point of any one of the pre-set work routes I through IX on the target driving path L.

The completion condition for learning soil information can be, for example, when automatic driving ends (driving stops). Alternatively, it can be when the system reaches the end of one of the work routes I through IX (which can be selected and set by the operator) on the target driving path L. Furthermore, it can be when the system reaches the end of one of the pre-set work routes I through IX on the target driving path L.

Preferably, the system is configured to start and end learning soil information when the third step (work path III) of the straight-line travel path l2 is reached after the start of work by automated driving, and to end when the third step (work path III) of the straight-line travel path l2 is reached. Note that the third step is an example; depending on the size of the field, it could be the first or fourth step, and the operator can select and set any step. This allows for more accurate learning of soil information for the entire field by learning soil information in one work step within the straight-line travel area R2. Conversely, if soil information is learned near the edge of the field, the measured values may be biased due to the presence of, for example, waterways next to the field, and may not necessarily reflect the entire field.

Furthermore, the soil information learning unit c72 is configured to allow the operator to start or stop learning soil information at their desired timing by performing a predetermined operation (for example, pressing a button) on the portable information terminal 6 or the control panel 7d, regardless of the above conditions. This improves convenience by allowing the operator to learn soil information at their desired location and timing.

When the soil information learning unit c72 finishes learning the soil information, it calculates the average values of the topsoil depth, SFV value, and growth evaluation value W during the learning process and stores them in the work information storage unit c53. At this time, the average value of the growth evaluation value W calculated and stored in the work information storage unit c53 will be referred to as the growth evaluation value W based on the learning results in the following explanation.

The fertilizer application device control unit c8 comprises a fertilizer application amount control unit c81, a fertilizer application mode execution unit c82, and a fertilizer application mode management unit c83.

The fertilizer application control unit c81 is a program that transmits control signals to the fertilizer application device 4 to control the amount of fertilizer applied, thereby performing the function of controlling the amount of fertilizer applied by the fertilizer application device 4.

The fertilization mode execution unit c82 is a program capable of executing multiple fertilization modes with different methods for determining the amount of fertilizer applied. It transmits information about the amount of fertilizer applied (control amount) from the fertilizer application control unit c81, thereby performing the function of determining the amount of fertilizer applied by the fertilizer application device 4 during the fertilization process.

The fertilization mode execution unit c82 includes the following executable fertilization modes (programs): basic fertilizer amount fertilization mode c821, fertilization map-based fertilization mode c822, soil information-based fertilization mode c823, and hybrid fertilization mode c824.

<Basic fertilizer application amount, fertilizer application mode>
The basic fertilizer application mode c821 is a mode in which a preset basic fertilizer application amount is determined as the fertilizer application amount of the fertilizer application device 4. That is, while the basic fertilizer application mode c821 is running (i.e., while the basic fertilizer application mode is selected), the fertilizer application amount of the fertilizer application device 4 is controlled to be the basic fertilizer application amount, and therefore remains constant under normal circumstances. The basic fertilizer application amount is determined by appropriately referring to the value set in the work information storage unit c53. If the value set in the work information storage unit c53 is changed, the fertilizer application amount of the fertilizer application device 4 is also changed.

<Fertilization map-based fertilization mode>
The fertilization map-based fertilization mode c822 is a mode in which the amount of fertilizer applied by the fertilizer application device 4 is determined based on the information in the fertilization map Dh. In other words, while the basic fertilization amount mode c821 is running (i.e., while the fertilization map-based fertilization mode is selected), the amount of fertilizer applied by the fertilizer application device 4 is determined by the following procedure.

This fertilization map-based fertilization mode c822 acquires the vehicle's position information (latitude and longitude) from the positioning device 5 at predetermined time intervals. Each time, it refers to the information on the fertilization map Dh, compares the position information on the fertilization map Dh with the position information acquired from the positioning device 5, and identifies the section K on the fertilization map Dh. Next, it acquires information on the target fertilization amount M set for the identified section K, and determines the acquired fertilization amount as the fertilization amount for the fertilization device 4.

<Soil Information-Based Fertilization Mode>
Soil information utilization fertilization mode c823 is a mode in which the amount of fertilizer applied by the fertilizer application device 4 is determined based on soil information. That is, while soil information utilization fertilization mode c821 is running (i.e., while soil information utilization fertilization mode is selected), the amount of fertilizer applied by the fertilizer application device 4 is determined by the following procedure.

The soil information utilization fertilization mode c823 acquires soil information from the soil information acquisition unit J at predetermined time intervals and calculates the growth evaluation value W using the above formula (1). Next, the calculated growth evaluation value W is compared with the growth evaluation value W based on the learning results stored in the work information storage unit c53, and the amount of fertilizer applied by the fertilizer application device 4 is determined based on the magnitude of the two values. The amount of fertilizer determined by the soil information utilization fertilization mode c823 can be calculated, for example, using the following formula (2).

(Equation 2) Fertilizer application amount = Basic fertilizer application amount × (100 - Fertilizer reduction rate (%)) / 100. However, when growth evaluation value W > growth evaluation value W based on learning results, the fertilizer reduction rate (%) = 20 × calculated growth evaluation value W / growth evaluation value W based on learning results. Also, when growth evaluation value W < growth evaluation value W based on learning results, the fertilizer reduction rate (%) = 0.

In other words, the higher the calculated growth evaluation value W is compared to the growth evaluation value W obtained from the learning results, the more fertile the location where the soil information was obtained is presumed to be compared to the average fertility of the entire field. Therefore, the fertilizer reduction rate (%) is increased, and the amount of fertilizer applied is reduced accordingly. Conversely, if the calculated growth evaluation value W is lower than the growth evaluation value W obtained from the learning results, the less fertile the location where the soil information was obtained is presumed to be compared to the average fertility of the entire field. Therefore, the fertilizer reduction rate (%) is set to 0, and the base fertilizer amount is determined as the amount of fertilizer applied without reduction. With the soil information utilization fertilization mode c824 configured in this way, it is possible to increase or decrease the amount of fertilizer applied, i.e., variable rate fertilization, while reflecting soil information measured in real time.

Furthermore, in the soil information utilization fertilization mode c824, immediately after the start of operation, if the soil information learning unit c72 has not yet learned the soil information, and the growth evaluation value W based on the learning results does not exist in the operation information storage unit c53, the fertilizer reduction rate (%) will be set to 0, and the basic fertilizer amount will be determined as the fertilizer amount of the fertilizer application device 4 until the soil information learning unit c72 completes learning the soil information.

Furthermore, even when the soil information-based fertilization mode c824 is not running, the control device C is configured to calculate the amount of fertilizer applied using the method described above in the soil information-based fertilization mode c823 at predetermined time intervals and transmit the calculated amount of fertilizer along with location information to the mobile information terminal 6. This enables the mobile information terminal 6 to create the soil information-based fertilization map Dj.

<Hybrid Fertilization Mode>
The hybrid fertilization mode c824 is a mode in which the amount of fertilizer applied by the fertilization device 4 is determined using information from the fertilization map and soil information. More specifically, while the hybrid fertilization mode c824 is running (i.e., while the hybrid fertilization mode is selected), the amount of fertilizer applied is determined by combining the amount of fertilizer determined by the fertilization map-based fertilization mode c822 and the amount of fertilizer determined by the soil information-based fertilization mode c824.

Specifically, if the fertilizer application rate determined by the fertilizer map-based fertilization mode c822 is M1 (kg/10a), and the fertilizer application rate determined by the soil information-based fertilization mode c823 is M2 (kg/10a), then the fertilizer application rate determined by the hybrid fertilization mode c824 can be calculated, for example, by the following formula (3).

(Formula 3) Fertilization amount = (γ1×M1+γ2×M2)/2
However, γ1 and γ2 are weighting coefficients that can be arbitrarily set by the operator, and γ1 + γ2 = 1. When setting the weighting coefficients, increasing the value of γ1 will give more weight to the amount of fertilizer M1 determined by the fertilization map-based fertilization mode c822, and increasing the value of γ2 will give more weight to the amount of fertilizer M2 determined by the soil information-based fertilization mode c823. This enables fine-grained variable fertilization according to the operator's needs. In addition, the quality of fertilization can be improved through a multifaceted evaluation of the field.

The fertilization mode management unit c83 performs the function of managing the fertilization mode executed by the control device C, and includes a fertilization mode selection/switching unit c831 and an automatic fertilization mode switching unit c832.

The fertilization mode selection switching unit c831 is a program that allows the operator to select a fertilization mode that can be executed by the fertilization mode execution unit c82 through a predetermined operation. For example, it displays a list of selectable fertilization modes on the display unit 6a or monitor 7e of the portable information terminal 6, and allows the operator to select the desired fertilization mode by operating the operation unit 6b or control panel 7d, causing the fertilization mode execution unit c82 to execute the selected fertilization mode.

<Automatic fertilization mode switching process>
The fertilization mode automatic switching unit c832 is a program that performs the function of automatically switching the fertilization mode (hereinafter referred to as the fertilization mode automatic switching function), and the fertilization mode automatic switching function can be turned on or off as appropriate by a predetermined operation by the operator. When the fertilization mode automatic switching function is turned on, the fertilization mode automatic switching unit c832 performs the following fertilization mode automatic switching process.

Figure 12 is a flowchart showing the flow of the automatic fertilization mode switching process.

The automatic fertilization mode switching unit c832 executes the fertilization map-based fertilization mode c822 when the automatic fertilization mode switching process begins (step #11). This enables fertilization using the fertilization map-based fertilization mode.

Next, the soil information acquisition unit J (soil depth sensor j1) determines whether the soil depth acquired is greater than or equal to the set depth (step #12). If it is determined that the soil depth is greater than or equal to the set depth, the soil information utilization fertilization mode c823 is executed (step #13). The set depth is predetermined by the operator. As a result, in areas with deep soil depth, the fertilization mode is automatically switched, and fertilization is performed using the soil information utilization fertilization mode. Consequently, in areas with deep soil depth, fertilization can be performed using a method that takes soil depth into account, effectively preventing lodging caused by overgrowth of seedlings due to deep soil depth. Afterward, when the soil depth falls below the set depth, the system returns to the fertilization map utilization fertilization mode (step #12, N).

Furthermore, if the automatic fertilization mode switching unit c832 determines that soil information cannot be acquired (Y in step #14), that is, that the control device C is unable to acquire soil information from the soil information acquisition unit J and that some kind of malfunction has occurred, it executes the basic fertilization rate mode c821 (step #15). This automatically switches the fertilization mode, and fertilization is performed using the basic fertilization rate mode. As a result, even if some malfunction occurs in the soil information acquisition unit J, causing problems with the progress of fertilization using the soil information utilization mode, the fertilization work can continue smoothly, effectively preventing a decrease in work efficiency.

Subsequently, the process returns to step #14. If it is determined that soil information can be acquired without problems (N in step #14), the system returns to the soil information-based fertilization mode (step #13).

The embodiments of the present invention have been described above. The present invention is not limited to the embodiments described above. It goes without saying that modifications can be made as appropriate within the scope of the technical idea. For example, the basic fertilizer application rate in the soil information utilization fertilization mode may be determined using the average value of the fertilization map of the field being worked on (see Figure 8). Fields often differ in soil type and other characteristics from region to region. By determining the basic fertilizer application rate while taking into account the characteristics of each region and incorporating information obtained from external sources (satellites, etc.), an appropriate basic fertilizer application rate can be set for each region.

The basic fertilizer application rate setting unit c71 may be configured to set the basic fertilizer application rate for a standard field by referencing the basic fertilizer application rate set for the field closest to that standard field. For example, in the example shown in Figure 7, when the standard field is field H1, the distance D1 to field H2 and the distance D2 to field H3 are compared. If the basic fertilizer application rate is set for the closer field H2, this can be set as the basic fertilizer application rate for field H1 of the standard field. This improves convenience.

<Other>
The following configurations can also be added.

In this robotic rice transplanter, a specific remote control operation after ridging will initiate a transition to herbicide replenishment mode. The herbicide replenishment process can be performed using the following procedure, improving convenience compared to conventional methods.
(1) After the ridges have been trimmed, the system will switch to herbicide replenishment mode through a specific operation (such as selecting from the remote control menu screen).
(2) The turning begins and automatically pauses at the appropriate time.
(3) Adjust the position of the rice transplanter by moving it forward and backward using the remote control, and lower the planting unit with the OK button.
(4) Once the herbicide replenishment is complete, press F + Start button to resume automatic driving.

When the system switches to herbicide replenishment mode, the robotic rice transplanter begins to turn and automatically pauses at the point "after the planting unit begins to lower but before planting begins." After pausing, pressing and holding the back button cancels the herbicide replenishment mode. Alternatively, after the planting unit lowering operation, pressing and holding the F button + start button resumes automatic operation. Until then, the system will not accept the automatic operation restart operation (F button + start button).

1. Work vehicle 2. Driving body 2a. Main frame 2b. Rear frame 2c. Floor step 3. Seedling planting section 3a. Seedling platform 3b. Planting device 3c. Center float 3d. Side float 3e. Planting tool 3f. Drive shaft 4. Fertilizer application device 4a. Air chamber 4b. Blower 4c. Fertilizer hopper 4d. Dispensing device 4e. Connecting pipe 4f. Fertilizer hose 4g. Intake duct 4h. Dispensing groove 4i. Dispensing roll 4j. Dispensing shaft 4m. Fertilizer application amount adjustment motor 5. Positioning device 6. Portable information terminal
7 Control Unit 7a Main Gear Lever 7b Steering Wheel 7c Straight-line Assist Lever 7d Control Panel 7e Monitor 7f Steering Shaft 7g Cockpit 9 Front Wheels 10 Rear Wheels 11 Lifting Linkage Device 11a Upper Link Arm 11b Lower Link Arm 12 Link Base Frame 13 Upper and Lower Link Arms 14 Lifting Hydraulic Cylinder C Control Device E Engine J Soil Information Acquisition Unit

Claims (3)

A work vehicle comprising a fertilizer application device and a positioning device for acquiring its own position, wherein, based on the position acquired by the positioning device, it uses a fertilizer application map in which the amount of fertilizer to be applied to each plot of field is set, acquires a target amount of fertilizer to be applied to the plot to which the vehicle's position belongs, and controls the amount of fertilizer applied by the fertilizer application device,
The system further comprises a soil information acquisition unit that acquires soil information of the field, and a control device that controls the amount of fertilizer applied by the fertilizer application device.
The aforementioned soil information acquisition unit includes a topsoil depth sensor for measuring the topsoil depth of the soil and a soil fertility sensor for measuring the soil fertility.
The system is configured to allow selection and execution of two modes: a fertilization mode that uses a fertilization map to determine the amount of fertilizer applied by the fertilization device based on the information in the fertilization map, and a soil information-based fertilization mode that uses soil information acquired from the soil information acquisition unit to determine the amount of fertilizer applied by the fertilization device.
The control device is characterized in that, while the fertilization map-based fertilization mode is being executed, when the topsoil depth measured by the topsoil depth sensor becomes equal to or greater than a set depth, the work vehicle automatically switches to the soil information-based fertilization mode. The work vehicle according to claim 1, characterized in that it is configured to create a soil information utilization fertilization map by calculating the average value of the amount of fertilizer to be applied by the soil information utilization fertilization mode for each plot of field, and to display the information of the fertilization map and the information of the soil information utilization fertilization map on a display unit. It is equipped with a field group information management unit that manages information about managed fields,
The aforementioned field group information management unit comprises a field group information creation unit for creating field group information, a field group analysis information creation unit for creating field group analysis information, and a field group information storage unit for storing information about managed fields.
The control device is further configured to execute a basic fertilizer application mode in which a preset basic fertilizer application amount is determined as the fertilizer application amount of the fertilizer application device.
The system includes a basic fertilizer application amount setting unit for setting the aforementioned basic fertilizer application amount,
The work vehicle according to claim 1, characterized in that the basic fertilizer application rate setting unit is configured to automatically set the basic fertilizer application rate for fields that were not selected as standard fields, based on the field group analysis information, when an operator selects a standard field from among multiple fields included in the managed field and sets the basic fertilizer application rate .