Work vehicle wireless management system

Abstract

To provide a work vehicle wireless management system that builds a more effective wireless communication network.SOLUTION: A work vehicle wireless management system uses a wireless communication network to manage work travel by work vehicles. A plurality of communication units 4 that handle wireless transmission data regarding work travel of the work vehicles are provided. Each of the communication units 4 uses a frequency band selected for each data type of the wireless transmission data from a plurality of different frequency bands as a frequency band to use, and performs communication processing on the wireless transmission data.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a work vehicle wireless management system that uses a wireless communication network to manage work travel by a work vehicle. [Background technology]

[0002] Recent work vehicles are equipped with wireless communication devices and can exchange information with external communication devices via wireless communication networks. In particular, self-driving 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.

[0003] For example, in the work vehicle operation system disclosed in Patent Document 1, the work vehicle is provided with a control module that outputs a control signal that controls operating equipment by operating an operation device, and a mobile information terminal serving as a remote control device is provided with a display that can display a pseudo operation device corresponding to the work vehicle's operation device, and a remote control unit that generates a remote operation signal based on an operation input to this pseudo operation device. By operating this pseudo operation device, a user can give the work vehicle operation commands similar to those of operating an actual operation device, and remotely control the operation of the work vehicle.

[0004] Furthermore, Patent Document 2 discloses a work vehicle cooperation system in which ground work is performed by a parent work vehicle and an unmanned sub work vehicle following the parent work vehicle. In this system, a manned parent work vehicle and an unmanned sub work vehicle following the parent work vehicle perform ground work by reciprocating straight line travel, repeating straight line travel and U-turn travel. At that time, the work travel target position data of the sub 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 sub ground work width data. The calculated work travel target position data is wirelessly transmitted to the sub work vehicle. The received work travel target position data becomes a steering control target value, and the sub work vehicle is unmanned. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-192740 A [Patent Document 2] JP 2014-178759 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the system according to Patent Document 1, a wireless communication network is established between the work vehicle and the remote control device, so that the travel of the work vehicle can be remotely controlled by the remote control device. In addition, in the system according to 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 work travel can be exchanged and cooperative travel work 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 data that cannot tolerate communication errors, such as emergency stop commands, and data that has a large amount of data 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. [Means for solving the problem]

[0007] The present invention is a work vehicle wireless management system that manages work travel by work vehicles using a wireless communication network, and is equipped with a plurality of communication units that handle wireless transmission data related to the work travel of the work vehicles, and the communication units use a frequency band selected for each data type of the wireless transmission data from a plurality of different frequency bands as the operating frequency band to communicate and process the wireless transmission data.

[0008] In this configuration, for the wireless transmission data related to the work travel of the multiple work vehicles, a frequency band selected for each data type of the wireless transmission data from a plurality of different frequency bands 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 a plurality of frequency bands, communication of the wireless transmission data is made multi-channel, which has the advantage of allowing the amount of wireless transmission data required for the work travel of the work vehicles to be appropriately distributed.

[0009] In one preferred embodiment of the present invention, a communication state determination unit that determines the communication state of the plurality of different frequency bands, and a usage frequency band selection unit that selects the usage frequency band to be assigned to each of the data types based on the communication state are provided. In this configuration, the communication state of each of the plurality of 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 plurality of frequency bands according to the communication state, it is possible to perform optimal wireless transmission according to the communication state.

[0010] 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 being higher than the second frequency band and the second frequency band being 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.

[0011] In wireless data transmission, a high frequency band has a characteristic that the amount of data transmission is large but the propagation characteristics are poor, whereas a low frequency band has a small amount of data transmission but the propagation characteristics are good. In consideration of this, 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. As a result, a frequency band appropriately selected according to the type of data required for the work vehicle's driving is used for data transmission.

[0012] In order to reliably perform work using a plurality of work vehicles as desired, it is important that a driver aboard the 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 who monitors 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 plurality of 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.

[0013] 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 part 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, at least a part of the data of the other data type, preferably important data, is wirelessly transmitted using the surplus. This improves the communication reliability of wireless transmission.

[0014] In one preferred embodiment of the present invention, 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 part 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. In this configuration, when a decrease in reception sensitivity or radio wave interference occurs in a specific frequency band, at least a part 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 having a good communication state, thereby ensuring a minimum communication reliability of wireless transmission.

[0015] When an unmanned work vehicle is connected to a wireless communication network and driven automatically, depending on the condition of the work site and the type of work, it may be necessary to avoid driving for work even if part of the wireless communication network is cut off. For this reason, in one preferred embodiment of the present invention, when at least one of the multiple frequency bands is determined to be defective, the unmanned work vehicle is forcibly stopped.

[0016] 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 on received signal strength alone requires simple circuits and programs, and is advantageous in terms of cost. A configuration in which the communication status is determined based on beacon signal check involves the transmission and reception 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 a poor communication status, and more appropriate measures can be taken when a poor communication status occurs. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram illustrating a basic configuration of an embodiment of a work vehicle wireless management system. [Diagram 2] 1 is a side view of a tractor, which is an example of a work machine that employs a work vehicle wireless management system. [Diagram 3] 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. [Figure 4] FIG. 2 is a plan view of the remote control device. [Diagram 5] FIG. 2 is a functional block diagram showing the functional parts of the unmanned work vehicle. [Figure 6] 4 is a flowchart showing an example of a wireless data transmission management routine in the work vehicle wireless management system. [Figure 7] 4 is a flowchart showing an example of a wireless data transmission management routine in the work vehicle wireless management system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 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 supervisor. 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 2.4 giga band, the second frequency band being 920 mega band, and the third frequency band being 429 mega band. Of course, other bands may be adopted.

[0019] The types of wireless transmission data handled by the wireless communication network of this embodiment are 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. In principle, the frequency band used for wireless transmission of the photographed image data is called the first usable frequency band, the frequency band used for wireless transmission of the control information data is called the second usable frequency band, and the frequency band used for wireless transmission of the emergency stop command is called the third usable frequency band.

[0020] The communication unit 4 includes a communication processing unit 40, a communication state determination unit 41, and a usage 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 necessary 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 the communication state is determined to be good through successful reception, and the communication state is determined to be poor through failure to receive the signal.

[0021] 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 the wireless transmission of control information data (i.e., the second frequency band to be used), and a frequency band to be used for the 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.

[0022] When the reception conditions of the first, second, and third frequency bands are all good, the first frequency band is assigned to the first operating frequency band, the second frequency band is assigned to the second operating frequency band, and the third frequency band is assigned to the third operating frequency band, as an initial setting.

[0023] 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 the communication conditions in the third frequency band are determined to be 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.

[0024] Conversely, when there is a surplus of data transmission capacity in at least one of the first usable frequency band, the second usable frequency band, and the third usable frequency band, particularly when there is a surplus of data transmission capacity in the first usable frequency band or the second usable frequency band, the control information data or the captured image data is redundantly transmitted using the usable frequency band with the surplus.

[0025] 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-driven manned work vehicle and an automatically-driven unmanned work vehicle, and the remote control device is carried by a user outside the work vehicle.

[0026] FIG. 2 shows a tractor as an example of a work vehicle participating in this work vehicle wireless management system. This tractor has a control unit 20 provided in the center of a vehicle body 1 supported by front wheels 11 and rear wheels 12. A working device 30, which is a rotary tilling device, is mounted on 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 a 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 a steering wheel 22 arranged on the control unit 20. A general-purpose terminal 3 equipped with a display, a speaker, a touch panel, and operation buttons is arranged on the control 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.

[0027] The cabin 21 of the tractor 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 the satellite navigation, it is possible to combine the satellite positioning module 80 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 a plurality of photographing cameras 85 for photographing the surroundings during traveling work, and an obstacle sensor 86 for detecting surrounding obstacles.

[0028] FIG. 3 shows how a field is cultivated by a manned working vehicle that is driven by a driver (user) and an unmanned working vehicle that is driven by an unmanned vehicle. Here, the manned working vehicle and the unmanned working vehicle are essentially the same type of tractor, and are equipped with the communication unit 4 shown in FIG. 1. The field is divided into a substantially rectangular central area and a peripheral area, also called a headland, that is defined along the ridges around the central area. In the central area, ground work is performed by reciprocating travel, so the travel trajectory is a repetition of a linear outward travel, a turning (U-turn) travel, and a linear return travel, and a turning (U-turn) travel. The headland is a turning area for the work travel in the central work area. In the peripheral area, a circular work travel is performed by repeating linear travel and turning travel at each corner area. Two-way wireless communication is performed between the manned working vehicle and the unmanned working vehicle. Furthermore, an observer (user) is standing on the ridge, carrying a remote control device 9. The remote control device 9 performs one-way wireless communication with the unmanned work vehicle.

[0029] A plan view of the remote control device 9 is shown in Figure 4. 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.

[0030] In this wireless communication network, wireless communication is carried out between the manned and unmanned work vehicles using two channels, a first usable frequency band and a second usable frequency band. The first usable frequency band is used to transmit image data captured by the photographing camera 95. The second usable 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 implement 30 (working depth, posture, etc.), the detection results of the obstacle sensor 86, etc.

[0031] A functional block diagram of the control system of an unmanned working vehicle is shown in Figure 5. The control system of a manned working vehicle is substantially the same, so the explanation of the control system of the unmanned working vehicle can also be used to explain the control system of the manned working vehicle.

[0032] 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 an on-board 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 also 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 on-board 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.

[0033] The output processing unit 7 is connected to a work traveling equipment group 70 consisting of a vehicle traveling equipment group 71 and a working equipment equipment group 72, and an alarm device 73 consisting of lamps, a buzzer, a speaker, etc. The vehicle traveling equipment group 71 includes control equipment related to vehicle traveling, such as an engine control device, a gear change control device, a braking control device, a steering control device, etc. The working equipment equipment group 72 includes power control devices such as a PTO clutch of the working equipment 30, which is a rotary tilling equipment in this embodiment, and a lifting cylinder control device of the lifting mechanism 31 that lifts and lowers the rotary tilling equipment.

[0034] The input processing unit 8 is connected with a satellite positioning module 80, an automatic / manual switching operation device 81, a driving state detection sensor group 82, a work state detection sensor group 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, and by operating the automatic / manual switching operation device 81 while traveling with manual steering, the vehicle travels with automatic steering. The driving state detection sensor group 82 includes sensors for detecting the states of operation devices (components of the work traveling operation device group 84) such as an engine speed adjustment device, an accelerator pedal, a brake pedal, and a steering wheel 22. The work state detection sensor group 83 includes sensors for detecting the states of the work operation devices (components of the work traveling operation device group 84) that adjust the drive and attitude of the work device 30.

[0035] 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 substantially constructed by software.

[0036] 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.

[0037] 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.

[0038] The route generating unit 54 reads the field contour data from the input field information and generates an appropriate travel route for the field. This travel route may be generated automatically based on basic initial parameters input by the driver, or a travel route generated by another computer may be downloaded. In either case, the travel route output from the route generating unit 54 is loaded into memory and used for automatic travel. Of course, this travel route can also be used for guidance for the work vehicle to travel along the travel route even in manual travel.

[0039] 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 travel target. 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 sequentially 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 gives the travel control unit 51 an automatic steering command to eliminate the azimuth deviation and position deviation.

[0040] 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. 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 photographed image data from 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.

[0041] Next, an example of a wireless data transmission management routine in an unmanned work vehicle will be described with reference to FIGS. First, the determination result from the communication state determination 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 at #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 that this automatic driving has stopped (#62).

[0042] If the communication state of the third frequency band is good (Yes branch in #01), it is further checked whether the communication states of the first frequency band and the second frequency band are good (#02). In this check, different processing is performed depending on the following four communication states.

[0043] (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).

[0044] (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 GHz 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 in 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. For this reason, 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. In other words, the first frequency band is used not only as the first usable frequency band but also as the second usable frequency band (#27).

[0045] (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 issues an automatic travel stop command to the work travel control unit 50 (#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).

[0046] (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).

[0047] [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 separated mainly for the purpose of explanation. In reality, each functional unit may be integrated with other functional units or separated 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 so that only the essential components are provided for each of the manned and unmanned vehicles. (5) In the above-described embodiment, a tractor equipped with a rotary tiller as the working implement 30 has been taken as the working vehicle, but in addition to such tractors, various working vehicles such as 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 implement 30 can also be used as embodiments. Also, one of the working vehicles may be a vehicle that does not actually perform work. [Industrial Applicability]

[0048] The present invention can be applied to a work vehicle wireless management system that uses a wireless communication network to manage work travel by a work vehicle. [Explanation of symbols]

[0049] 3: General-purpose terminal 4: Communication unit 40: Communication processing unit 41: Communication status determination unit 42: Frequency band selection section 50: Work travel control unit 61: Transmission data processing unit 62: Mode switching section 85: Shooting camera 86: Obstacle sensor 9: Remote control device 91: Emergency stop button 92: Automatic driving start button 93: Pause button 95: Shooting camera AC: Automatic driving control unit CU: Control unit

Claims

1. 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.

2. 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.

3. The vehicle wireless management system according to claim 2 , wherein the communication state determination unit determines the communication state by checking a received signal strength or a beacon signal, or by both.

4. 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.

5. A work vehicle wireless management system as described in 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 having the surplus of data transmission capacity.

6. A work vehicle wireless management system as described in 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 by the operating frequency band that is the frequency band judged to be good.

7. The work vehicle wireless management system according to claim 1 , wherein when at least one of the plurality of frequency bands is determined to be defective, the work vehicle is forced to stop.

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