JP7626822B2 - Work vehicle wireless management system - Google Patents

Description

The present invention relates to a work vehicle wireless management system that uses a wireless communication network to manage work travel by work vehicles.

Recently, work vehicles are equipped with wireless communication devices and can exchange information with external communication devices via wireless communication networks. In particular, autonomous work vehicles receive various control commands related to work driving from other work vehicles or remote control devices brought by managers, and perform control operations based on the received control commands.

For example, in the work vehicle operation system disclosed in Patent Document 1, the work vehicle is equipped with a control module that outputs control signals that control operating equipment through operation of an operation device, and the mobile information terminal serving as a remote control device is equipped with a display that can display a pseudo operation device that corresponds to the work vehicle's operation device, and a remote control unit that generates a remote operation signal based on operation input to this pseudo operation device. By operating this pseudo operation device, the user can give operation commands to the work vehicle similar to those used when operating an actual operation device, and remotely control the operation of the work vehicle.

Furthermore, Patent Document 2 discloses a work vehicle cooperation system in which ground work is performed by a parent work vehicle and an unmanned child work vehicle that follows the parent work vehicle. In this system, a manned parent work vehicle and an unmanned child work vehicle that follows the parent work vehicle perform ground work by reciprocating straight-line travel that repeats straight-line travel and U-turn travel. At that time, the work travel target position data of the child work vehicle is calculated taking into consideration the parent travel trajectory data calculated from the parent position data indicating the position of the parent work vehicle, the parent ground work width data, and the child ground work width data. The calculated work travel target position data is wirelessly transmitted to the child work vehicle. The received work travel target position data becomes the steering control target value, and the child work vehicle is unmanned.

JP 2014-192740 A JP 2014-178759 A

In the system of Patent Document 1, a wireless communication network is established between the work vehicle and the remote control device, so that the driving operation of the work vehicle can be remotely controlled by the remote control device. In the system of Patent Document 2, a wireless communication network is established between the manned work vehicle and the unmanned work vehicle, so that data related to each other's driving operation can be exchanged and cooperative driving operations can be performed. The types and amounts of data exchanged between the work vehicle and the remote control device and between the manned work vehicle and the unmanned work vehicle are increasing year by year. In addition, the types of data communicated include a mixture of data that cannot tolerate communication errors, such as emergency stop commands, and data that is large in volume even if a communication error is not fatal, such as surrounding photographed images. In light of this situation, there is a demand for a work vehicle wireless management system that establishes a more effective wireless communication network between multiple work vehicles.

The present invention is a work vehicle wireless management system that uses a wireless communication network to manage work travel by a work vehicle, and is equipped with multiple communication units that handle wireless transmission data related to the work travel of the work vehicle, and the communication units use a frequency band selected for each data type of the wireless transmission data from multiple different frequency bands as the operating frequency band to communicate and process the wireless transmission data.

In this configuration, for wireless transmission data related to the work travel of multiple work vehicles, a frequency band selected from multiple different frequency bands for each data type of wireless transmission data is used as the frequency band to be used. Therefore, an appropriate frequency band can be used for wireless transmission of data depending on the data type. In addition, by using multiple frequency bands, communication of wireless transmission data is made multi-channel, which has the advantage of allowing appropriate distribution of the amount of wireless transmission data required for the work travel of the work vehicles.

In one preferred embodiment of the present invention, a communication state determination unit that determines the communication state of the multiple different frequency bands, and a usage frequency band selection unit that selects the usage frequency band to be assigned to each data type based on the communication state are provided. In this configuration, the communication state of each of the multiple frequency bands used as the usage frequency band is checked, so that it is possible to identify a frequency band with reduced reception sensitivity or a frequency band that is subject to radio interference. Therefore, by adjusting the purpose of use of the multiple frequency bands according to the communication state, optimal wireless transmission according to the communication state is possible.

In one preferred embodiment of the present invention, the multiple frequency bands include a first frequency band, a second frequency band, and a third frequency band, the first frequency band is higher than the second frequency band, the second frequency band is higher than the third frequency band, the data types include photographed image data around the work vehicle, control information data related to the driving operation of the work vehicle, and an emergency stop command for emergency stopping the work vehicle, and when all of the multiple frequency bands are in a good condition, the first frequency band is used as the operating frequency band for the photographed image data, the second frequency band is used as the operating frequency band for the control information data, and the third frequency band is used as the operating frequency band for transmitting the emergency stop command.

In wireless data transmission, in high frequency bands, the amount of data transmitted is large but the propagation characteristics are poor, whereas in low frequency bands, the amount of data transmitted is small but the propagation characteristics are good. Taking this into consideration, in the above-mentioned configuration, the first frequency band, which has the highest frequency, is used for wireless transmission of captured image data around the work vehicle, which has a large amount of data but the loss of the transmitted data is not fatal. In addition, the third frequency band, which has the lowest frequency, is used for wireless transmission of emergency stop commands, which has a small amount of data but the loss of the transmitted data can be fatal. Furthermore, the second frequency band is used for wireless transmission of control information data, which has a small amount of data and the loss of the transmitted data is not fatal. In this way, a frequency band appropriately selected according to the type of data required for the work vehicle's driving is used for data transmission.

In order to ensure that work using multiple work vehicles is performed as desired, it is important that a driver on board a manned work vehicle monitors the automatic operation of the unmanned work vehicle. Furthermore, since the movement of the unmanned work vehicle may enter the blind spot of the driver of the manned work vehicle, or the driver of the manned work vehicle may miss an unexpected movement of the unmanned work vehicle, in order to deal with such a situation, it is also important that a monitor standing at the work site monitoring the movement of the unmanned work vehicle uses a remote control device to make an emergency stop of the unmanned work vehicle. For this reason, in one preferred embodiment of the present invention, the multiple work vehicles include a manually operated manned work vehicle and an automatically operated unmanned work vehicle, and the communication of the captured image data and the transmission of the control information data are performed between the manned work vehicle and the unmanned work vehicle, and the transmission of the emergency stop command is performed between a remote control device operated by a user outside the work vehicle and the unmanned work vehicle.

In one preferred embodiment of the present invention, when there is a surplus of data transmission capacity in at least one of the operating frequency bands, at least a portion of the data content of at least one of the data types is redundantly transmitted using the operating frequency band with the surplus of data transmission capacity. In this configuration, when there is a surplus in the operating frequency band allocated according to the data type, the surplus is used to wirelessly transmit at least a portion of the data of the other data type, preferably important data. This improves the communication reliability of wireless transmission.

In one preferred embodiment of the present invention, when at least one of the multiple frequency bands is determined to be poor and at least one is determined to be good, at least a portion of the wireless transmission data of the data type transmitted in the operating frequency band to which the frequency band determined to be poor is assigned is transmitted in the operating frequency band that is the frequency band determined to be good. In this configuration, when a decrease in reception sensitivity or radio wave interference occurs in a specific frequency band, at least a portion of the wireless transmission data of the data type to which the specific frequency band is assigned as the operating frequency band can be wirelessly transmitted by interrupting another operating frequency band with a good communication state, thereby ensuring a minimum communication reliability of wireless transmission.

When an unmanned work vehicle is connected to a wireless communication network and traveling automatically, depending on the condition of the work site and the type of work, it may be necessary to avoid traveling for work even if part of the wireless communication network is cut off. For this reason, in one preferred embodiment of the present invention, if at least one of the multiple frequency bands is determined to be defective, the unmanned work vehicle is forcibly stopped.

In a preferred embodiment of the present invention, the communication status determination unit is configured to determine the communication status based on received signal strength or beacon signal check, or both. A configuration in which the communication status is determined based only on received signal strength requires simple circuits and programs, and is cost-effective. A configuration in which the communication status is determined based on beacon signal check involves the sending and receiving of actual data (beacon signal), making the determination of the communication status more reliable. A configuration in which the communication status is determined based on both received signal strength and beacon signal check makes it easier to track down the cause of poor communication status, and more appropriate measures can be taken when poor communication status occurs.

FIG. 1 is an explanatory diagram illustrating a basic configuration of an embodiment of a work vehicle wireless management system. 1 is a side view of a tractor, which is an example of a work machine that employs a work vehicle wireless management system. 1 is a schematic diagram showing an example of a vehicle wireless management system including a manned vehicle, an unmanned vehicle, and a remote control device. FIG. 2 is a plan view of the remote control device. FIG. 2 is a functional block diagram showing the functional parts of the unmanned work vehicle. 4 is a flowchart showing an example of a wireless data transmission management routine in the work vehicle wireless management system. 4 is a flowchart showing an example of a wireless data transmission management routine in the work vehicle wireless management system.

Next, one embodiment of the work vehicle wireless management system of the present invention will be described with reference to the drawings. FIG. 1 shows the basic configuration of this work vehicle wireless management system. The wireless communication network of this work vehicle wireless management system includes a communication unit 4 equipped on each of the two work vehicles and a remote control device 9 carried by the monitor. The frequency bands handled by this wireless communication network are a first frequency band, a second frequency band, and a third frequency band. The first frequency band is the highest band, followed by the second frequency band and the third frequency band, which are the lowest bands. Each frequency band is officially regulated, with the first frequency band being the 2.4 giga band, the second frequency band being the 920 mega band, and the third frequency band being the 429 mega band. Of course, other bands may be used.

The types of wireless transmission data handled by the wireless communication network in this embodiment are photographed image data of the area around the work vehicle, control information data related to the driving operation of the work vehicle, and an emergency stop command for emergency stopping the work vehicle. In principle, the frequency band used for wireless transmission of photographed image data is called the first frequency band used, the frequency band used for wireless transmission of control information data is called the second frequency band used, and the frequency band used for wireless transmission of emergency stop commands is called the third frequency band used.

The communication unit 4 includes a communication processing unit 40, a communication state determination unit 41, and a frequency band selection unit 42. The communication processing unit 40 has a function of converting input data into a form that can be wirelessly transmitted, and a function of converting received wireless transmission data into a required form and outputting it. The communication state determination unit 41 determines the communication state in the first frequency band, the second frequency band, and the third frequency band. When the communication state is determined by the received signal strength, the strength of the input signal from the antenna 49 is measured. If the measured strength is equal to or greater than a threshold value, the communication state is determined to be good, and if the measured strength is below the threshold value, the communication state is determined to be poor. When the communication state is determined by a beacon signal check, each communication unit 4 periodically transmits a beacon signal, and if the reception is successful, the communication state is determined to be good, and if the reception is unsuccessful, the communication state is determined to be poor.

The frequency band selection unit 42 selects a frequency band to be used for the captured image data (i.e., the first frequency band to be used), a frequency band to be used for wireless transmission of control information data (i.e., the second frequency band to be used), and a frequency band to be used for wireless transmission of an emergency stop command (i.e., the third frequency band to be used) based on the communication state determined by the communication state determination unit 41.

When the reception conditions of the first, second, and third frequency bands are all good, the first frequency band is assigned to the first usage frequency band, the second frequency band is assigned to the second usage frequency band, and the third frequency band is assigned to the third usage frequency band as the initial setting.

When the reception state of any of the first, second, and third frequency bands is poor, the following emergency stop notification process can be arbitrarily adopted.
(1) When the communication state of the first frequency band is determined to be poor and the communication state of the second frequency band is determined to be good, the captured image data to which the first frequency band is assigned as the first operating frequency band is wirelessly transmitted together with the control information data using the second operating frequency band. At that time, it is preferable to convert the captured image data into still image data or the like, rather than into video data, to reduce the amount of data. Similarly, when the communication state of the second frequency band is determined to be poor and the communication state of the first frequency band is determined to be good, the control information data to which the second frequency band is assigned as the second operating frequency band is wirelessly transmitted together with the captured image data using the first operating frequency band.
(2) When the communication state of the third frequency band is determined to be poor and the communication state of the first frequency band or the second frequency band is determined to be good, an emergency stop command, for which the third frequency band is assigned as the third operating frequency band, is wirelessly transmitted using the first frequency band or the second frequency band as the third operating frequency band.
(3) If it is determined that the communication conditions in the third frequency band are poor, a situation may arise in which the emergency stop command cannot be transmitted wirelessly, and the work vehicle will be forced to stop.
(4) If any one of the first, second, and third frequency bands is determined to be defective, the work vehicle is forced to stop for the time being.

Conversely, when there is a surplus of data transmission capacity in at least one of the first, second and third operating frequency bands, particularly when there is a surplus of data transmission capacity in the first or second operating frequency band, the control information data or the captured image data is redundantly transmitted using the operating frequency band with the surplus.

Next, as a specific application example of the work vehicle wireless management system shown in Figure 1, we will explain a system in which the communication unit 4 is equipped on a manually operated manned work vehicle and an automatically operated unmanned work vehicle, and the remote control device is carried by a user outside the work vehicle.

Figure 2 shows a tractor as an example of a work vehicle participating in this work vehicle wireless management system. This tractor has a steering unit 20 at the center of the vehicle body 1 supported by the front wheels 11 and the rear wheels 12. A work device 30, which is a rotary tilling device, is installed at the rear of the vehicle body 1 via a hydraulic lifting mechanism 31. The front wheels 11 function as steering wheels, and the running direction of the tractor is changed by changing the steering angle with the steering mechanism 13. The steering angle of the front wheels 11 is changed by the operation of the steering mechanism 13. The steering mechanism 13 includes a steering motor 14 for automatic steering. During manual driving, the front wheels 11 can be steered by operating the steering wheel 22 arranged on the steering unit 20. A general-purpose terminal 3 equipped with a display, a speaker, a touch panel, and operation buttons is arranged on the steering unit 20. This general-purpose terminal 3 has a function of providing information to the driver and a function of inputting information from the driver.

The tractor cabin 21 is provided with a satellite positioning module 80 configured as a GNSS (global navigation satellite system) module. As a component of the satellite positioning module 80, a satellite antenna for receiving GNSS signals (including GPS signals) is attached to the ceiling area of the cabin 21. In order to complement satellite navigation, the satellite positioning module 80 can be combined with an inertial navigation module incorporating a gyro acceleration sensor and a magnetic direction sensor. The inertial navigation module may be provided in a location separate from the satellite positioning module 80. The vehicle body 1 is further equipped with multiple camera cameras 85 that capture images of the surroundings while traveling, and an obstacle sensor 86 that detects obstacles in the surroundings.

Figure 3 shows how a field is cultivated by a manned work vehicle with a driver (user) on board and an unmanned work vehicle that runs unmanned. Here, the manned work vehicle and the unmanned work vehicle are essentially the same type of tractor, and are equipped with the communication unit 4 shown in Figure 1. The field is divided into a roughly rectangular central area and a peripheral area, also called a headland, that is defined around the central area along the ridges. In the central area, ground work is performed by reciprocating travel, so the travel trajectory is a repetition of linear outbound travel, turning (U-turn) travel, linear return travel, and turning (U-turn) travel. The headland is the turning area for work travel in the central work area. In the peripheral area, circular work travel is performed by repeating linear travel and turning at each corner area. Two-way wireless communication is performed between the manned work vehicle and the unmanned work vehicle. Furthermore, an observer (user) carrying a remote control device 9 is standing on the ridge. The remote control device 9 wirelessly communicates one-way with the unmanned work vehicle.

Figure 4 shows a plan view of the remote control device 9. This remote control device 9 is a handheld type that can be operated with one hand. On its surface, a power button, an emergency stop button 91, an automatic driving start button 92, and a pause button 93 are provided. When the emergency stop button 91 is pressed, an emergency stop command is sent to the communication unit 4 of the unmanned work vehicle. Similarly, when the automatic driving start button 92 is pressed, an automatic driving start command is sent, and when the pause button 93 is pressed, a pause command is sent.

In this wireless communication network, wireless communication is performed between the manned and unmanned work vehicles using two channels, a first operating frequency band and a second operating frequency band. The first operating frequency band is used to transmit image data captured by the image capture camera 95. The second operating frequency band is used to exchange control information data generated by each of the manned and unmanned work vehicles. The control information data includes the state of the vehicle body 1 of each work vehicle (vehicle position, engine RPM, vehicle speed, etc.), the state of the work device 30 (working depth, posture, etc.), and the detection results of the obstacle sensor 86.

Figure 5 shows a functional block diagram of the control system of an unmanned work vehicle. The control system of a manned work vehicle is essentially the same, so the explanation of the control system of the unmanned work vehicle can be used to explain the control system of the manned work vehicle.

The control unit CU, which is the core element of the control system of the unmanned work vehicle, is equipped with an output processing unit 7 and an input processing unit 8 as input/output interfaces. For wireless data exchange with the outside, the communication unit 4 described in FIG. 1 is provided, and this communication unit 4 is connected to the control unit CU via the vehicle-mounted LAN. Of course, the communication unit 4 may be built inside the control unit CU. Also, a general-purpose terminal 3 equipped with a graphic user interface is connected so that the movement of the work vehicle can be managed by user operation. In FIG. 5, the general-purpose terminal 3 is a fixed type connected to the vehicle-mounted LAN, but if it is configured to be capable of wireless data exchange with the control unit CU via the communication unit 4, it can be taken outside the vehicle and used.

The output processing unit 7 is connected to a work driving equipment group 70 consisting of a vehicle driving equipment group 71 and a work equipment equipment group 72, and an alarm device 73 consisting of lamps, buzzers, speakers, etc. The vehicle driving equipment group 71 includes control equipment related to vehicle driving, such as engine control equipment, gear change control equipment, braking control equipment, steering control equipment, etc. The work equipment equipment group 72 includes power control equipment such as a PTO clutch for the work equipment 30, which is a rotary tilling device in this embodiment, and a lifting cylinder control equipment for the lifting mechanism 31 that lifts and lowers the rotary tilling device.

The input processing unit 8 is connected to a satellite positioning module 80, an automatic/manual switching operation device 81, a group of driving state detection sensors 82, a group of work state detection sensors 83, a photographing camera 85, an obstacle sensor 86, and the like. The automatic/manual switching operation device 81 is a switch for selecting either an automatic driving mode in which the vehicle travels with automatic steering or a manual steering mode in which the vehicle travels with manual steering. For example, by operating the automatic/manual switching operation device 81 while traveling in the automatic steering mode, the vehicle travels with manual steering can be switched to traveling with manual steering, and by operating the automatic/manual switching operation device 81 while traveling with manual steering, the vehicle travels with automatic steering can be switched to traveling with manual steering. The group of driving state detection sensors 82 includes sensors for detecting the state of operation devices (components of the group of work driving operation devices 84) such as an engine speed adjustment device, an accelerator pedal, a brake pedal, and a steering wheel 22. The group of work state detection sensors 83 includes sensors for detecting the state of a work operation device (components of the group of work driving operation devices 84) that adjusts the drive and attitude of the work device 30.

The control unit CU incorporates a work driving control unit 50, an automatic driving control unit AC, a transmission data processing unit 61, and a mode switching unit 62 as functional units that are essentially constructed using software.

The work driving control unit 50 includes a driving control unit 51, a work control unit 52, and an engine control unit 53. The driving control unit 51 controls the vehicle driving equipment group 71. Since this tractor is configured to be able to drive both automatically (automatic steering) and manually (manual steering), the driving control unit 51 has a manual driving control function and an automatic driving control function. When the manual driving control function is being executed, the vehicle driving equipment group 71 is controlled based on the operation by the driver. When the automatic driving control function is being executed, a steering control signal (a type of operation control signal) generated based on an automatic steering command given from the automatic driving control unit AC is output to the steering motor 14. The work control unit 52 gives a work control signal (a type of operation control signal) to the working equipment equipment group 72 in order to control the movement of the working equipment 30. The engine control unit 53 gives an engine control signal (a type of operation control signal) to the operating equipment of the engine.

The automatic driving control unit AC includes a route generation unit 54, a route setting unit 55, a vehicle position calculation unit 56, and an automatic work driving command unit 57.

The route generation unit 54 reads the field's external shape data from the input field information, and generates an appropriate driving route for this field. This driving route may be generated automatically based on basic initial parameters input by the driver, or a driving route generated by another computer may be downloaded. In either case, the driving route output from the route generation unit 54 is expanded in memory and used for automatic driving. Of course, this driving route can also be used for guidance to guide the work vehicle along the driving route even when driving manually.

The route setting unit 55 sequentially reads out the travel routes expanded in the memory and sets them as the travel route that is the target for travel. The vehicle position calculation unit 56 calculates the position of the vehicle body 1 or the position of the work device 30 based on the positioning data successively sent from the satellite positioning module 80. The automatic work travel command unit 57 calculates the azimuth deviation and position deviation between the target travel route and the vehicle position, and issues an automatic steering command to the travel control unit 51 to eliminate the azimuth deviation and position deviation.

The mode switching unit 62 has a function of switching, through user operation, between a manned work vehicle mode in which the vehicle functions as a manned work vehicle and an unmanned work vehicle mode in which the vehicle functions as an unmanned work vehicle when multiple work vehicles work together in cooperation. The transmission data processing unit 61 handles control information data indicating the work driving state detected by the driving state detection sensor group 82, the work state detection sensor group 83, and the obstacle sensor 86, and image data captured by the photographing camera 85. The transmission data processing unit 61 converts various types of data into an appropriate format for wireless transmission data, and converts sent wireless transmission data into a data format that can be processed internally.

Next, an example of a wireless data transmission management routine in an unmanned work vehicle will be described with reference to FIGS.
First, the judgment result from the communication state judgment unit 41 is acquired, and it is checked whether the third frequency band communication state is good (#01). In the default state, this third frequency band is used as the third usage frequency band for transmitting an emergency stop command from the remote control device 9. Therefore, if the communication state of the third frequency band is poor (No branch in #01), the transmission data processing unit 61 issues an automatic driving stop command to the work driving control unit 50 (#61). This causes the unmanned work vehicle to stop automatic driving. Furthermore, a stop notification process (driving a lamp or buzzer) is executed to indicate the stop of this automatic driving (#62).

If the communication state of the third frequency band is good (Yes branch in #01), it is further checked whether the communication state of the first frequency band and the second frequency band is good (#02). In this check, different processing is performed depending on the following four communication states.

(1) When the communication conditions of the first frequency band and the second frequency band are good (#10):
The first frequency band is used as a first usable frequency band (#11), and the second frequency band is used as a second usable frequency band (#12).

(2) When communication conditions are good only in the first frequency band (#20):
The first frequency band is used as the first operating frequency band (#21). Therefore, the captured image data is wirelessly transmitted using the first frequency band, which is the 2.4 giga band. Furthermore, it is checked whether there is a margin for data transmission in the first operating frequency band, which is the first frequency band (#22). If there is a margin for data transmission in the first operating frequency band (Yes branch in #22), the control information data that was originally intended to be transmitted in the second frequency band is loaded on the margin of the first operating frequency band (first frequency band). Therefore, the control information data is simplified (reduced in data amount) to the extent necessary (#23). Then, the control information data is transmitted using the first frequency band. That is, the first frequency band is also used as the second operating frequency band (#24). If there is no margin for data transmission in the first operating frequency band (No branch in #22), the first frequency band is used as the first operating frequency band and the second operating frequency band, and is used for wireless transmission of both the captured image data and the control information data. Therefore, the captured image data is simplified (data volume reduced) to the extent necessary by frame thinning, still image conversion, etc. (#25). Similarly, the control information data is also simplified (data volume reduced) to the extent necessary (#26). Then, the captured image data and the control information data are transmitted using the first frequency band. That is, the first frequency band is used not only as the first usable frequency band but also as the second usable frequency band (#27).

(3) When the communication conditions of the first frequency band and the second frequency band are poor (#30):
It is checked whether there is a margin for data transmission in the third operating frequency band, which is the third frequency band (#31). If there is a margin for data transmission in the third operating frequency band (Yes branch in #31), the captured image data that was originally intended to be transmitted in the first frequency band and the control information data that was originally intended to be transmitted in the second frequency band are loaded in the margin of the third operating frequency band (third frequency band). Since the amount of transmission data in the third frequency band, which is 429 MHz, is small, the captured image data is simplified to the extent necessary (#34), the third frequency band is also used as the first operating frequency band, and the simplified captured image data is wirelessly transmitted in the third frequency band (#35). Similarly, the control information data is also simplified to the extent necessary (#36), the third frequency band is also used as the second operating frequency band, and the simplified control information data is wirelessly transmitted in the third frequency band (#37). If there is a margin for data transmission in the third operating frequency band (No branch in #31), the transmission data processing unit 61 gives the work driving control unit 50 an automatic driving stop command (#32). This causes the unmanned work vehicle to stop automatic travel, and then a stop notification process (driving a lamp or buzzer) is executed to indicate that automatic travel has stopped (#33).

(4) When communication conditions are good only in the second frequency band (#40):
The second frequency band is used as the second operating frequency band (#41). Therefore, the control information data is wirelessly transmitted using the second frequency band, which is the 920 MHz band. Furthermore, it is checked whether there is a margin for data transmission in the second operating frequency band, which is the second frequency band (#42). If there is a margin for data transmission in the second operating frequency band (Yes branch in #42), the captured image data that is originally intended to be transmitted in the first frequency band is loaded in the margin of the second operating frequency band (second frequency band). Therefore, the captured image data is simplified (reduced in data amount) to the extent necessary (#43). Then, the captured image data is transmitted using the second frequency band. That is, the second frequency band is also used as the first operating frequency band (#44). If there is no margin for data transmission in the second operating frequency band (No branch in #42), the wireless transmission of the captured image data is stopped (#45), and the stop of the transmission of the captured image data is notified (#46).

[Another embodiment]
(1) In the above embodiment, three frequency bands are used, but more frequency bands may be used.
(2) In the above-described embodiment, the remote control device 9 is used simply as a signal transmitter that performs one-way wireless communication, but instead, a highly functional communication terminal such as a tablet computer may be used as the remote control device 9. In this case, two-way wireless communication is also possible between the remote control device 9 and the work vehicle, and, for example, captured image data can be displayed on a touch panel of the communication terminal serving as the remote control device 9.
(3) The functional units in the functional block diagram shown in FIG. 5 are divided mainly for the purpose of explanation. In reality, each functional unit may be integrated with other functional units or divided into multiple functional units. For example, the automatic driving control unit AC may be built in the general-purpose terminal 3.
(4) In the above embodiment, the manned and unmanned vehicles are the same type and their control systems are substantially the same, but the manned and unmanned vehicles may be different types of vehicles. Furthermore, the control systems may be provided only with the essential components for each of the manned and unmanned vehicles.
(5) In the above-described embodiment, a tractor equipped with a rotary tiller as the working device 30 is taken as the working vehicle, but in addition to such tractors, various working vehicles can be adopted as embodiments, for example, agricultural vehicles such as rice transplanters, fertilizer applicators, and combine harvesters, or construction vehicles equipped with a dozer, roller, or the like as the working device 30. Furthermore, one of the working vehicles may be a vehicle that does not actually perform work.

The present invention can be applied to a work vehicle wireless management system that uses a wireless communication network to manage work travel by work vehicles.

3: General-purpose terminal 4: Communication unit 40: Communication processing unit 41: Communication state determination unit 42: Used frequency band selection unit 50: Work driving control unit 61: Transmission data processing unit 62: Mode switching unit 85: Photographing camera 86: Obstacle sensor 9: Remote control device 91: Emergency stop button 92: Automatic driving start button 93: Pause button 95: Photographing camera AC: Automatic driving control unit CU: Control unit

Claims (7)

A work vehicle wireless management system that manages work travel by a work vehicle using a wireless communication network,
A plurality of communication units are provided for handling wireless transmission data relating to the work travel of the work vehicle, and
the communication unit uses a frequency band selected from a plurality of different frequency bands for each data type of the wireless transmission data as a usage frequency band, and communicates and processes the wireless transmission data;
The plurality of frequency bands include a first frequency band and a third frequency band, the first frequency band being higher than the third frequency band;
The data types include photographed image data of the vicinity of the work vehicle, control information data related to the traveling operation of the work vehicle, and an emergency stop command for emergency stopping the work vehicle, and
When all of the plurality of frequency bands are in a good state, the first frequency band is used as the operating frequency band for the captured image data, and the third frequency band is used as the operating frequency band for transmitting the emergency stop command,
A work vehicle wireless management system in which, if the third frequency band is determined to be defective, the automatic traveling of the work vehicle is forcibly stopped even if the first frequency band is in a good condition. a communication state determination unit that determines communication states of the plurality of different frequency bands;
2. The vehicle wireless management system according to claim 1, further comprising: a frequency band selection unit that selects the frequency band to be allocated to each of the data types based on the communication state. The vehicle wireless management system according to claim 2, wherein the communication status determination unit determines the communication status by checking the received signal strength or the beacon signal, or both. A plurality of the work vehicles including a manually-driven manned work vehicle and an automatically-driven unmanned work vehicle are provided,
the communication of the photographed image data and the transmission of the control information data are performed between the manned work vehicle and the unmanned work vehicle,
4. A work vehicle wireless management system according to claim 1, wherein the emergency stop command is transmitted between a remote control device operated by a user outside the work vehicle and the unmanned work vehicle. The work vehicle wireless management system according to any one of claims 1 to 4, wherein, when there is a surplus of data transmission capacity in at least one of the operating frequency bands, at least a portion of the data content of at least one of the data types is redundantly transmitted using the operating frequency band that has a surplus of data transmission capacity. The work vehicle wireless management system according to any one of claims 1 to 5, wherein, when at least one of the plurality of frequency bands is judged to be poor and at least one is judged to be good, at least a portion of the wireless transmission data of the data type transmitted in the operating frequency band to which the frequency band judged to be poor is assigned is transmitted in the operating frequency band that is the frequency band judged to be good. The work vehicle wireless management system according to any one of claims 1 to 6, wherein the work vehicle is forcibly stopped if at least one of the plurality of frequency bands is determined to be defective.

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