Data sharing system

Abstract

The disclosed data sharing system comprises a plurality of vehicles (2) existing within a network (3) and a server (1) that defines a role for each of the vehicles (2), the data sharing system making data sharing between the vehicles (2) possible. The server (1) defines the role of a first vehicle for one of the vehicles (2) and defines the role of second vehicles for the other vehicles (2). The first vehicle stores a database obtained by collecting data generated by the second vehicles, and provides the data contained in the database to the second vehicles in response to a request from the second vehicles.

Description

Technical Field

[0001] This invention relates to a data sharing system for realizing data sharing between vehicles.

Background Art

[0002] Conventionally, a data sharing system that uses vehicle-to-vehicle communication to share information with vehicles existing around the host vehicle is known (see Patent Document 1). According to this type of system, steering information and acceleration / deceleration information of a vehicle can be shared in real time with surrounding vehicles, and the prediction accuracy of the behavior of each vehicle can be improved. On the other hand, a data sharing system has also been proposed that enables sharing not only information on the behavior of surrounding vehicles but also driving environment and road information via a server (see Patent Documents 2 and 3). According to this type of system, it is possible to easily share road construction information and traffic accident information that other vehicles have discovered in the past.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In data sharing systems using servers, there are advantages such as easier centralized data management and maintenance of data quality for server administrators (e.g., automobile manufacturers). However, there is a challenge in simultaneously reducing server maintenance costs and improving communication quality. For example, when building a global data sharing system, it may be necessary to install servers in each country (or region), which tends to increase costs. Also, the greater the physical distance between the server and each vehicle, the more likely communication problems (e.g., communication delays or interruptions) are to occur, potentially impairing convenience for vehicle users. Therefore, it is desirable to increase the number of servers installed to ensure communication quality, which further increases costs.

[0005] One of the objectives of this project is to provide a data sharing system that addresses the aforementioned challenges and achieves both cost reduction in server maintenance and improved communication quality. Beyond this objective, another objective of this project is to achieve effects and benefits derived from the various configurations described in the "Modes for Carrying Out the Invention" section below, which cannot be obtained with conventional technologies. [Means for solving the problem]

[0006] The data sharing system disclosed can be implemented in the following manner (examples of application) and solve at least some of the above-mentioned problems. Each of the manners from Manifest 2 onward is an additional manner that can be selected as appropriate, and each of the manners can be omitted. None of the manners from Manifest 2 onward disclose any manner or configuration that is essential to this case.

[0007] Embodiment 1. The disclosed data sharing system comprises a plurality of vehicles located within a network and a server that assigns a role to each of the vehicles, and is a data sharing system that enables data sharing between the vehicles. The server assigns the role of a first vehicle to one of the vehicles and the role of a second vehicle to the other vehicles. The first vehicle also stores and manages a database created by collecting data generated by the second vehicle, and provides the data contained in the database to the second vehicle upon request from the second vehicle.

[0008] The server assigns the role of a third vehicle to at least one of the vehicles, which is neither the first vehicle nor the second vehicle. 。 Furthermore, the third vehicle stores a copy of the database stored in the first vehicle. 。

[0009] manner 2 The above aspects 1 In this case, it is preferable that the server changes the role of the first vehicle to the second vehicle and changes the role of the third vehicle to the first vehicle when any of the following conditions 1 to 3 are met. Condition 1. The first period of responsibility has elapsed since the role of the first vehicle was established. Condition 2. The communication interruption time for the first vehicle has become equal to or greater than the initial interruption time. Condition 3. The first vehicle has moved at least a first departure distance from the area in which the role of the first vehicle is set.

[0010] manner 3 The above aspects 1 In embodiments including the above, it is preferable that the server changes the role of at least one of the second vehicles to the third vehicle if any of the following conditions 4 to 7 are met. Condition 4. The second period of responsibility has elapsed since the role of the third vehicle was established. Condition 5. The communication interruption time of the third vehicle has become equal to or greater than the second interruption time. Condition 6. The third vehicle has moved at least two distances away from the area where the role of the third vehicle is set. Condition 7. The role of the third vehicle has been changed to that of the first vehicle.

[0011] manner 4 In embodiments including the above embodiment 1, it is preferable that the server, when selecting the vehicle to which the role of the first vehicle is set, calculates the first cumulative time when the vehicle was connected to the network and the second cumulative time when the vehicle assumed the role of the first vehicle, and selects the vehicle based on the value obtained by dividing the second cumulative time by the first cumulative time. manner 5 In an embodiment including the above embodiment 1, it is preferable that the server determines the target for which the role of the first vehicle is set based on the deterioration state of the vehicle and the communication stability.

[0012] manner 6 The above aspects 1 In embodiments including the above, it is preferable that the server, when selecting the vehicle to which the role of the third vehicle is set, calculates the first cumulative time when the vehicle is connected to the network and the third cumulative time when the vehicle has assumed the role of either the first vehicle or the third vehicle, and selects the vehicle based on the value obtained by dividing the third cumulative time by the first cumulative time. manner 7 In an embodiment including the above embodiment 1, it is preferable that the server determines the target for which the role of the third vehicle is set based on the deterioration state of the vehicle and the communication stability. manner 8Another data sharing system disclosed is a data sharing system that enables data sharing between the vehicles, comprising a plurality of vehicles located in a network and a server that assigns a role to each of the vehicles. The server assigns the role of a first vehicle to one of the vehicles, the role of a second vehicle to the other vehicles, and the role of a third vehicle, which is neither the first nor the second vehicle, to at least one of the vehicles. The first vehicle stores a database containing data generated by the second vehicle and provides the data contained in the database to the second vehicle upon request from the second vehicle. The third vehicle stores a copy of the database stored in the first vehicle. manner 9 The above aspects 8 In embodiments including the above, it is preferable that the server changes the role of the first vehicle to the second vehicle and changes the role of the third vehicle to the first vehicle when any of the following conditions are met: condition 1 that the first assignment period has elapsed since the role of the first vehicle was set; condition 2 that the communication interruption time of the first vehicle is equal to or greater than the first interruption time; and condition 3 that the first vehicle is at least a first departure distance away from the area in which the role of the first vehicle is set. manner 10 The above aspects 8 In embodiments including the above, it is preferable that the server changes the role of at least one of the second vehicles to the third vehicle if any of the following conditions are met: condition 4 that a second assignment period has elapsed since the role of the third vehicle was set; condition 5 that the communication interruption time of the third vehicle is equal to or greater than the second interruption time; condition 6 that the third vehicle is at least a second departure distance away from the area in which the role of the third vehicle is set; or condition 7 that the role of the third vehicle is changed to the first vehicle. manner 11 The above aspects 8In an embodiment including the above, when the server selects the vehicle for which the role of the third vehicle is to be set, the server calculates the first cumulative time when the vehicle is connected to the network and the third cumulative time when the vehicle has served as the first vehicle or the third vehicle, and preferably selects based on the value obtained by dividing the third cumulative time by the first cumulative time. Embodiment 12 . The above embodiment 8 In an embodiment including the above, it is preferable that the server determines the target for which the role of the third vehicle is to be set based on the deterioration state and communication stability of the vehicle. Embodiment 13 . Another data sharing system of the disclosure includes a plurality of vehicles existing in a network and a server that sets roles for each of the vehicles, and is a data sharing system that realizes data sharing between the vehicles. The server sets the role of the first vehicle for one of the vehicles and sets the role of the second vehicle for the other vehicles. The first vehicle stores a database formed by collecting data generated by the second vehicle, and provides the data included in the database to the second vehicle in response to a request from the second vehicle. When the server selects the vehicle for which the role of the first vehicle is to be set, the server calculates the first cumulative time when the vehicle is connected to the network and the second cumulative time when the vehicle has served as the first vehicle, and selects based on the value obtained by dividing the second cumulative time by the first cumulative time.

Advantages of the Invention

[0013] In the disclosed data sharing system, the server sets the roles of the first vehicle and the second vehicle for each vehicle, and the first vehicle stores the database and provides data to the second vehicle. In this way, by moving a part of the server's functions to the first vehicle, the cost for maintaining and managing the server can be reduced. Also, since the role of the first vehicle is set for one of the vehicles existing in the network, it is difficult for a communication failure to occur between the first vehicle and the second vehicle, and the communication quality can be improved.

Brief Description of the Drawings

[0014] [Figure 1] This is a schematic diagram illustrating the overview of the data sharing system. [Figure 2] This is a schematic diagram illustrating the area covered by the network. [Figure 3] This is a block diagram illustrating the configuration of a data sharing system. [Figure 4] This table shows the roles of servers and vehicles (master vehicle, replica vehicle, client vehicle) involved in the data sharing system. [Figure 5] (A) to (C) are examples of tables stored on the server. [Figure 6] This is an example of a database stored in a master vehicle. [Figure 7] This is a flowchart illustrating the procedure for assigning roles. [Figure 8] This is a flowchart illustrating the procedure for changing roles. [Modes for carrying out the invention]

[0015] The following describes a data sharing system according to an embodiment of the present invention. This data sharing system enables data sharing between vehicles and comprises multiple vehicles in a network and a server that can be connected to each vehicle. In this embodiment, multiple vehicles exist in a single network, and each vehicle in that network can connect to a single server. The data to be shared is location-related data (location-related data). This data includes, for example, road information for route searching, congestion information (vehicle density information, average stay time information), obstacle information, road construction information, road surface unevenness information, white line / road marking fading information, traffic regulation information, traffic enforcement information, road flooding information, etc.

[0016] The network in this embodiment refers to a network (local network, localized network) established for each region or district, and means a communication network formed to correspond to each area, which is created by dividing the ground surface into predetermined sizes. Each area may be, for example, an area divided in a mesh pattern, an area divided according to administrative boundaries, or an area divided based on the location of wireless communication equipment (e.g., base stations and antennas).

[0017] The vehicle according to this embodiment has at least a positioning function and a communication function. The vehicle according to this embodiment also includes engine vehicles that run using an engine (internal combustion engine) as a power source, motor vehicles that run using a motor (electric motor) as a power source, hybrid vehicles (HEV, Hybrid Electric Vehicle) that run using both an engine and a motor as power sources, plug-in hybrid vehicles (PHEV, Plug-in Hybrid Electric Vehicle) that can be charged or supplied with power from an external source, etc.

[0018] A plug-in hybrid vehicle is a hybrid vehicle equipped with an engine and motor as power sources, a generator as a power generation device, and a battery as an energy storage device, and is capable of external charging of the battery or external power supply from the battery. The former plug-in hybrid vehicle is equipped with a charging port (inlet) for inserting a charging cable that supplies power from an external charging facility, or a contactless power receiving device. The latter plug-in hybrid vehicle is equipped with an outlet for external power supply, or a contactless power supply device. It is also possible to install both a charging port and an outlet on a single plug-in hybrid vehicle. [Examples]

[0019] [1. Equipment configuration] Figure 1 is a schematic diagram illustrating an overview of a data sharing system as an embodiment. This data sharing system comprises multiple vehicles 2 located within a network 3, and a server 1 that assigns predetermined roles to each vehicle 2. The vehicles 2 are connected cars that have the function of communicating with the server 1 via the network 3. Vehicles 2 can communicate with other vehicles 2 via at least the network 3, and may also be capable of vehicle-to-vehicle communication (direct communication with other vehicles 2). The information provision service to vehicles 2 using the network 3 is also called CCS (Connected Car Service).

[0020] Server 1 is a computer capable of providing information to each vehicle 2 via network 3. Unlike conventional server devices, Server 1 in this embodiment does not have the function of providing information about the driving environment or roads to each vehicle 2. Server 1 has the function of having one of the vehicles 2 present in network 3 take over this role, and the function of providing each vehicle 2 with identification information to identify that vehicle 2. Furthermore, multiple such networks 3 are provided. One server 1 can connect to multiple networks 3, for example, via the internet. It is sufficient to have one or more servers 1 worldwide, and it is not necessary to provide one server 1 for each network 3.

[0021] Figure 2 is a schematic diagram illustrating the area corresponding to network 3. Network 3 is formed to correspond to regional meshes 4, which are created by dividing the Earth's surface into a mesh-like area without gaps, for example, based on latitude and longitude. One regional mesh 4 is, for example, several kilometers square to several tens of kilometers square in size. One network 3 may be associated with each individual regional mesh 4, or one network 3 may be associated with multiple adjacent regional meshes 4. In this embodiment, a mobile phone network roughly corresponding to one regional mesh 4 is associated with one network 3. The assumed number of vehicles 2 within one network 3 is, for example, several hundred to several thousand.

[0022] Figure 3 is a block diagram showing the configuration of the server 1 and vehicle 2 included in the data sharing system. Server 1 is equipped with a computing means 10 (role setting means) having a processor 11 and memory 12, a communication means 13, and a storage means 14. The computing means 10 is the main device for the computational processing performed on server 1, and the communication means 13 is a device for exchanging information with vehicle 2 and other computers via network 3.

[0023] The storage means 14 is a device that stores the contents of the arithmetic processing performed on server 1 as a processing program, and also stores the results of the arithmetic processing. The contents of the processing program are appropriately read into the processor 11 and memory 12 and executed. The storage means 14 may be provided separately from server 1. Also, server 1 may be one of several virtual servers included in a single physical server, or it may be a combination of several physical servers functioning as a single virtual server.

[0024] Vehicle 2 is equipped with a computing means 20 having a processor 21 and memory 22, a positioning means 23, a detection means 24, a communication means 25, and a storage means 26. The computing means 20 is the main device for the computing processing performed in vehicle 2. The positioning means 23 acquires the position information of vehicle 2 based on detection information from a GNSS (Global Navigation Satellite System) device (not shown), a vehicle speed sensor, a steering angle sensor, a yaw rate sensor, a radio signal strength sensor, etc. (for example, a car navigation device).

[0025] The detection means 24 detects information about the driving environment and roads surrounding the vehicle 2. Specific examples of the detection means 24 include radar devices, ultrasonic sensor devices, video cameras, and infrared camera devices that detect objects (other vehicles, obstacles, police vehicles, etc.) around the vehicle 2 or on the road surface. The information acquired by the detection means 24 is linked to the position information acquired by the positioning means 23 to become position-related data.

[0026] The communication means 25 is a device for vehicle 2 to exchange information with server 1 and other vehicles 2. The storage means 26 is a device that stores the contents of the arithmetic processing performed by vehicle 2 as a processing program, and also stores the results of the arithmetic processing. The contents of the processing program are appropriately read into the processor 21 and memory 22 and executed. The processing program and the results of the arithmetic processing stored in the storage means 26 will be in accordance with the role of each vehicle 2 as described below.

[0027] [2. Control Configuration] Figure 4 is a table showing the functions and roles of Server 1 and Vehicle 2. In this embodiment, Server 1 has the function of assigning one of three types of roles to each of the multiple Vehicles 2 present in Network 3. These roles are the role of the master vehicle (first vehicle), the role of the client vehicle (second vehicle), and the role of the replica vehicle (third vehicle). These roles are not fixedly assigned to a specific Vehicle 2, but are dynamically assigned to all Vehicles 2 in Network 3.

[0028] The master vehicle is responsible for collecting location-related data generated by its own vehicle and other vehicles 2 to create a database, and for storing and managing this database in the storage means 26. One of the vehicles 2 present in the network 3 is appointed as the master vehicle by the server 1 on a rotating basis. The location-related data contained in the database is provided to the vehicle 2 in response to requests from its own vehicle and other vehicles 2. The generation of location-related data may be performed by all vehicles 2, including the master vehicle, or it may be performed only by the client vehicles as described later.

[0029] The role of master vehicle is assigned to only one vehicle at a time within a single network 3. The period during which the role of master vehicle is assigned (appointed) is basically a maximum of the first assignment period (several weeks to several months). After that period has elapsed, the role of that vehicle 2 is changed to a client vehicle, and the role of master vehicle is taken over by one of the vehicles 2 that is currently acting as a replica vehicle. When the role of master vehicle is terminated (removed), the database information that was stored in the memory means 26 up to that point is erased. Note that the above master vehicle setting conditions (appointment conditions and removal conditions) may be changed, and specific examples will be described later.

[0030] A replica vehicle is a vehicle that stores and manages a copy (replica) of the database stored in the master vehicle in a storage means 26. From among the vehicles 2 existing in the network 3, one or more vehicles are designated as replica vehicles by the server 1 on a rotating basis. The contents of the copy stored in the replica vehicle may be updated, for example, whenever a change is made to the master vehicle's database, or at predetermined intervals. For example, it may be updated every predetermined time, or whenever the number of database changes reaches a predetermined number. If a database copy is not necessary, the replica vehicle may be omitted.

[0031] The role of a replica vehicle is preferably assigned to one or more vehicles within a single network 3. The period for which a replica vehicle is assigned a role (the term of office of a replica vehicle) is basically a maximum of the second assignment period (for example, a period longer than the first assignment period). After that period has elapsed, the role of that vehicle 2 is changed to a client vehicle, and the role of the replica vehicle is taken over by one of the vehicles 2 that currently has the role of a client vehicle. When a replica vehicle is released from its role, the database copy information that was stored in the storage means 26 up to that point is erased. Note that the above conditions for setting up replica vehicles (appointment conditions and dismissal conditions) may be changed, and specific examples will be described later.

[0032] If, before the second assignment period has elapsed since the role of a replica vehicle was assigned, the role of vehicle 2, which was then the master vehicle, is terminated, one of the vehicles 2 that currently has the role of a replica vehicle will be appointed as the master vehicle. In this case, a copy of the database stored in the memory means 26 will be used as the master vehicle's database. Also, since the number of replica vehicles decreases when a replica vehicle is promoted to a master vehicle, the role of a replica vehicle will be newly assigned to one of the vehicles 2 that currently has the role of a client vehicle.

[0033] A client vehicle is a vehicle 2 that generates location-related information by associating the information acquired by the detection means 24 with the location information acquired by the positioning means 23, and transmits this location-related information to the master vehicle. The IP address and port number of the master vehicle to which the location-related information is transmitted are obtained as appropriate by querying the server 1. Each piece of location-related information generated by the client vehicle is appended to and stored in the master vehicle's database. The role of a client vehicle is set for all vehicles 2 in the network 3 that are neither the master vehicle nor a replica vehicle.

[0034] Server 1 assigns the above-described roles to each vehicle 2. Server 1 records information to identify the location and role of each vehicle 2 within the network 3. On the other hand, unlike server devices in the conventional technology, the individual location-related information generated by the client vehicles and the database that is a compilation of that information are not recorded in Server 1 of this embodiment. In other words, in this embodiment, the burden on Server 1 is reduced by moving the functions that were previously handled by the server device in the conventional technology to the master vehicle.

[0035] Figures 5(A) to 5(C) show examples of tables stored in the storage means 14 of server 1. The address management table shown in Figure 5(A) is a table that stores unique information for identifying each vehicle 2. The address management table records the vehicle identification number (VIN) of each vehicle 2, as well as the IP address and port number related to communication with each vehicle 2. Each vehicle 2 periodically communicates with server 1 to notify server 1 of its own IP address and port number, and to obtain the IP address and port number of the master vehicle.

[0036] The area management table shown in Figure 5(B) is a table that stores unique information to identify the network 3 (or the regional mesh 4 corresponding to that network 3) to which each vehicle 2 is connected. The area management table records the vehicle identification number of each vehicle 2 and the area identification number (area ID) of the network 3 (or the regional mesh 4 in which the vehicle 2 is located) to which each vehicle 2 is connected.

[0037] The role management table shown in Figure 5(C) is a table that stores the role of each vehicle 2. The role management table records the vehicle identification number and the role of each vehicle 2. For master vehicles and replica vehicles, information such as the date and time when the role was set, and the cumulative time that the master vehicle or replica vehicle has had a role set may also be added.

[0038] Figure 6 shows an example of a database recorded in the master vehicle's memory means 26. This database records location-related information generated by the client vehicle. The location-related information includes information detected by the client vehicle's detection means 24 (e.g., obstacles, road surface bumps / sinks, traffic enforcement, etc.) and the detected location (latitude and longitude). Information such as the date and time the location-related information was generated and an area identification number may also be added.

[0039] The information in the database managed by the master vehicle is made available to all vehicles 2 within the network 3 where the master vehicle resides. For example, vehicles 2 other than the master vehicle periodically transmit their own location information to the master vehicle and request nearby location-related information. Upon receiving this request, the master vehicle searches the database based on the received location information and returns location-related information present around the vehicle 2. The returned location-related information is displayed, for example, on a map image on a car navigation system. Similar control is performed in the master vehicle. The master vehicle periodically searches the database based on its own location information and obtains location-related information present around its vehicle. The obtained location-related information is displayed, for example, on a map image on a car navigation system.

[0040] [3. Examples of role setting conditions] The role of Master Vehicle is assigned to any vehicle 2 in Network 3 if no Master Vehicle exists in Network 3, or if the current Master Vehicle is dismissed. The conditions for selecting a suitable vehicle 2 as Master Vehicle (appointment conditions) may be selected from the conditions shown below. The role of Master Vehicle may also be dismissed if any of the dismissal conditions shown below are met. Furthermore, the appointment and dismissal of the Master Vehicle role may be determined by combining multiple appointment and dismissal conditions.

[0041] [Appointment conditions] Condition M1. The current master vehicle was a replica vehicle when it was dismissed. Condition M2. The connection time to network 3 is within the specified time range. Condition M3. The degree of deterioration of the vehicle 2 or the storage means 26 is within a predetermined deterioration range. Condition M4. High communication stability (good communication quality). Condition M5. The ratio (T2 / T1) of the second cumulative time T2, during which the vehicle acted as the master vehicle, to the first cumulative time T1 connected to network 3 is less than or equal to a predetermined value (or within a predetermined ratio range). Condition M6. The above ratio (T2 / T1) is smallest.

[0042] [Conditions for dismissal] Condition M7. The first assignment period has elapsed since the master vehicle's role was established. Condition M8. The communication interruption time of the master vehicle has exceeded the first interruption time. Condition M9. The master vehicle has moved more than the first departure distance from the area where the role of the master vehicle is set (an area corresponding to one network 3). Condition M10. The first departure time has elapsed since the master vehicle left the area.

[0043] Condition M1 above states that when a master vehicle is dismissed, a successor will be selected preferentially from among the replica vehicles. The connection time in condition M2 above refers to the time elapsed since the date and time when communication with server 1 was first established within network 3. Condition M2 states that vehicle 2, which is neither too new nor too old, is suitable as the master vehicle.

[0044] The degree of degradation in condition M3 above refers to the aging deterioration of vehicle 2 and the deterioration of its storage read / write performance. Condition M3 also states that vehicle 2, which is neither new nor significantly deteriorated, is suitable as the master vehicle. Condition M4 above states that the master vehicle should be set considering the stability of communication between the two vehicles. The above conditions M5 and M6 are examples of methods for achieving fair role assignment of the master vehicle in a rotational (alternating) system.

[0045] The initial assignment period for condition M7 described above is, for example, several weeks to several months. The communication interruption time in condition M8 above refers to the time during which communication with the master vehicle could not be established within network 3. The communication interruption time can be determined, for example, by having server 1 periodically check whether communication with the master vehicle can be established. Alternatively, it can be determined by having a vehicle other than the master vehicle notify server 1 of the master vehicle's absence if it is unable to establish communication with the master vehicle. Conditions M9 and M10 above are examples of conditions that are determined when the master vehicle moves to a location with a different area identification number.

[0046] The role of a replica vehicle is assigned to any vehicle 2 in Network 3 if a predetermined number of replica vehicles do not exist within Network 3, or if the current replica vehicle is dismissed. The conditions for selecting a suitable vehicle 2 for the replica vehicle (appointment conditions) may be selected from the conditions shown below. Furthermore, the role of a replica vehicle may be dismissed if any of the dismissal conditions shown below are met. In addition, the appointment and dismissal of a replica vehicle may be determined by combining multiple appointment and dismissal conditions.

[0047] [Appointment conditions] Condition R1. The current replica vehicle was the client's vehicle when it was dismissed. Condition R2. The connection time to network 3 is within the specified time range. Condition R3. The degree of deterioration of the vehicle 2 or the storage means 26 is within a predetermined deterioration range. Condition R4. High communication stability (good communication quality). Condition R5. The ratio (T3 / T1) of the third cumulative time T3 in which the vehicle played the role of a master vehicle or replica vehicle to the first cumulative time T1 connected to network 3 is less than or equal to a predetermined value (or within a predetermined ratio range). Condition R6. The above ratio (T3 / T1) is smallest.

[0048] [Conditions for dismissal] Condition R7. The second period of assignment has elapsed since the role of the replica vehicle was established. Condition R8. The communication interruption time for the replica vehicle has exceeded the second interruption time. Condition R9. The replica vehicle has moved more than the second escape distance from the area where the role of the replica vehicle is set (an area corresponding to one network 3). Condition R10. The second evacuation time has elapsed since the replica vehicle left the area.

[0049] Condition R1 above states that when a replica vehicle is retired, its successor will be selected preferentially from among the client vehicles. Conditions R2 to R4 above are the same as conditions M2 to M4 above, and describe the conditions for vehicle 2 that are suitable for a replica vehicle. Conditions R5 and R6 described above are examples of methods for achieving fair role assignment for replica vehicles in a rotational (alternating) system.

[0050] The second assignment period under condition R7 described above is, for example, longer than the first assignment period, ranging from several months to about a year. Conditions R8-R10 above are the same as conditions M8-M10 above. Note that the role of a replica vehicle has less computational load, communication load, and storage load compared to the role of a master vehicle. Therefore, the dismissal conditions for a replica vehicle (conditions R7-R10) can be made more lenient than the dismissal conditions for a master vehicle (conditions M7-M10), allowing for a relatively longer term of service for a replica vehicle.

[0051] [4. Flowchart] Figure 7 is a flowchart illustrating the procedure for setting the role of each vehicle 2 when Server 1 receives communication from each vehicle 2. Server 1 periodically receives communication from each vehicle 2, checks the IP address and port number of each vehicle 2 based on the address management table, and updates the IP address and port number as necessary. Server 1 also obtains the area identification number of the network 3 (or regional mesh 4 where the vehicle 2 is located) to which each vehicle 2 is connected based on the location information of each vehicle 2, and updates the area management table. Subsequently, based on the area management table and role management table, it searches for master vehicles and replica vehicles that exist within the same network 3 as the vehicle 2.

[0052] Step A1 determines whether the master vehicle is located within the same network 3 as vehicle 2. If the condition in step A1 is not met, the process proceeds to step A2, where vehicle 2 is assigned the role of master vehicle and recorded in the role management table. A specific example of vehicle 2 to which the role of master vehicle is assigned in step A2 is vehicle 2 that was the first to connect to that network 3 (or regional mesh 4).

[0053] If the conditions in step A1 are met, the process proceeds to step A3. In step A3, it is determined whether a predetermined number of replica vehicles exist within the same network 3 as vehicle 2. If the conditions in step A3 are not met, the process proceeds to step A4, where the role of vehicle 2 is set to that of a replica vehicle and recorded in the role management table. A specific example of vehicle 2 to which the role of a replica vehicle is set in step A4 is vehicle 2 that is the second vehicle connected to that network 3 (or regional mesh 4). If the conditions in step A3 are met, the process proceeds to step A5, where the role of vehicle 2 is set to that of a client vehicle.

[0054] Figure 8 is a flowchart illustrating the procedure for changing the role of each vehicle 2. Based on this flowchart, Server 1 periodically manages whether a role change or reconfiguration is necessary for each network 3 (or regional mesh 4). Step B1 determines whether the conditions for dismissing the master vehicle are met. If these conditions are met, the process proceeds to steps B2-B4 to select a successor master vehicle; otherwise, it proceeds to step B5. Step B5 determines whether the conditions for dismissing the replica vehicle are met. If these conditions are met, the process proceeds to steps B6-B8 to select a successor replica vehicle; otherwise, the control of this flowchart ends.

[0055] In step B2, in order to select a candidate master vehicle from among the replica vehicles, a value is calculated to quantitatively evaluate the past experience of the master vehicle. Specifically, the first cumulative time T1, when each replica vehicle was connected to network 3, and the second cumulative time T2, when each replica vehicle served as the master vehicle, are calculated, and the ratio T2 / T1 (the value obtained by dividing the second cumulative time T2 by the first cumulative time T1) is calculated. A smaller value of ratio T2 / T1 indicates that the master vehicle has less experience and a lower contribution to network 3 as a whole.

[0056] In the following step B3, the communication stability and degradation level (degradation level of vehicle 2 and memory means 26) of each replica vehicle are checked. Then, in step B4, a successor master vehicle that meets the appointment criteria for the master vehicle is selected from among the replica vehicles. For example, the replica vehicle with the smallest ratio T2 / T1 value becomes the successor master vehicle. Alternatively, a replica vehicle with a relatively small ratio T2 / T1 value and a degradation level within a predetermined degradation range becomes the successor master vehicle. The role of vehicle 2, which was previously the master vehicle, is changed to that of a client vehicle. After that, the process proceeds to steps B6 to B8 to select a successor for the vacant replica vehicle.

[0057] In step B6, values ​​are calculated to quantitatively evaluate the past experience of master and replica vehicles in order to select a candidate replica vehicle from among the client vehicles. Specifically, the first cumulative time T1, when each client vehicle was connected to network 3, and the third cumulative time T3, when each client vehicle acted as either a master or replica vehicle, are calculated, and the ratio T3 / T1 (the value obtained by dividing the third cumulative time T3 by the first cumulative time T1) is calculated. A smaller value of the ratio T3 / T1 indicates less experience as a master or replica vehicle and a lower contribution to network 3 as a whole.

[0058] In the following step B7, the communication stability and degradation level (degradation level of vehicle 2 and memory means 26) of each client vehicle are checked. Then, in step B8, a successor replica vehicle that meets the appointment criteria for a replica vehicle is selected from among the client vehicles. For example, the client vehicle with the smallest ratio T3 / T1 value becomes the successor replica vehicle. Alternatively, a client vehicle with a relatively small ratio T3 / T1 value and a degradation level within a predetermined degradation range becomes the successor replica vehicle. The role of vehicle 2, which was previously a replica vehicle, is changed to that of a client vehicle unless it is upgraded to a master vehicle.

[0059] [5. Effects] (1) The data sharing system of this embodiment includes multiple vehicles 2 located within a network 3 and a server 1 that assigns a role to each vehicle 2 in order to enable data sharing among multiple vehicles 2. The server 1 assigns the role of master vehicle (first vehicle) to one of the vehicles 2 and the role of client vehicle (second vehicle) to the other vehicles 2. The master vehicle stores a database containing location-related data generated by the client vehicles and provides the location-related data contained in the database to the client vehicles in response to requests from the client vehicles.

[0060] In this way, by assigning the roles of master vehicle and client vehicle to vehicle 2 within network 3, and having the master vehicle centrally manage the database related to location data, the computational load on server 1 and the capacity of the storage means 14 can be significantly reduced compared to when the database is managed by server 1, thereby reducing the maintenance costs of server 1.

[0061] Furthermore, in this data sharing system, a master vehicle within network 3 provides location-related data to client vehicles within the same network 3. In other words, communication is completed within an area with a relatively close physical distance. This reduces the probability of communication failures (e.g., communication delays or interruptions) between the master vehicle and client vehicles during the transfer of location-related data, thereby improving communication quality. Consequently, it is possible to achieve both cost reduction for the maintenance of server 1 and improvement of communication quality within network 3.

[0062] In this embodiment of the data sharing system, there is only one master vehicle within a single network 3 that centrally manages the database. Alternatively, it is conceivable to configure the system so that the database is stored in the storage means 26 of all vehicles 2, and each vehicle 2 manages location-related data individually. However, in this case, each vehicle 2 would hold unnecessary location-related data that is not used by its own vehicle, raising concerns about pressure on and degradation of the in-vehicle storage. With the configuration of this embodiment, by delegating database management to the master vehicle, pressure on and degradation of the in-vehicle storage in the other vehicles 2 can be avoided. Furthermore, by having only the master vehicle function as a server, cache reuse can be encouraged, improving the response time related to the provision of location-related data.

[0063] Furthermore, compared to having each vehicle 2 manage its own database, this reduces the load on network 3 (the degree of communication congestion). For example, if N vehicles 2 within a single network 3 generate one piece of location-related data and share it with other vehicles 2, and assuming the size of the location-related data is 1 [KB], the total communication volume on network 3 will be N(N-1) [KB]. On the other hand, if only the master vehicle manages the database, there is no need to share the location-related data with all vehicles 2. Each vehicle 2 requests the data from the master vehicle only when it needs to use the location-related data. Therefore, if the number of times the master vehicle provides location-related data to each vehicle 2 in response to each vehicle 2's request is M, the total communication volume on network 3 will be (N-1) + M [KB]. Here, assuming N=1000, the communication volume in the former case is 999,000 [KB], and the communication volume in the latter case is 999 + M [KB]. It is highly probable that the load on network 3 will be smaller in the latter case.

[0064] Furthermore, compared to having each vehicle 2 manage its own database, this reduces the incompleteness of data for each network 3 (regional mesh 4). In other words, it takes time for location-related data generated by other vehicles 2 in network 3 to be transmitted to all vehicles 2, and it is difficult to confirm that this information has been fully disseminated throughout network 3. On the other hand, if only the master vehicle manages the database, location-related data can be collected efficiently and managed easily.

[0065] (2) In the above data sharing system, Server 1 may be configured to play the role of a replica vehicle (third vehicle) that is neither a master vehicle nor a client vehicle. The replica vehicle is configured for at least one of the vehicles 2 in Network 3 and stores a copy (replica) of the database stored in the master vehicle. With this configuration, even when the master vehicle is absent (for example, when communication is lost, when it is moved to a distant location, when it is scrapped, etc.), the role of the master vehicle can be quickly taken over by the replica vehicle. Therefore, smooth and reliable data sharing can be achieved.

[0066] (3) Server 1 described above may change the role of the master vehicle to that of the client vehicle and change the role of the replica vehicle to that of the master vehicle if any of the following conditions 1 to 3 are met. Condition 1. The first assignment period has elapsed since the master vehicle's role was assigned. Condition 2. The communication interruption time of the master vehicle has exceeded the initial interruption time. Condition 3. The master vehicle has moved more than the first escape distance from the area where the role of the master vehicle is set.

[0067] This configuration allows for accurate tracking of the master vehicle's assignment period and absence status, enabling the replica vehicle to be promoted to master vehicle and facilitating smooth data sharing. For example, it avoids situations where only one vehicle (vehicle 2) is continuously burdened with the role of master vehicle, thereby increasing fairness in the rotation. Furthermore, if the master vehicle moves outside the area (regional mesh 4) corresponding to network 3, its role can be quickly transferred to the replica vehicle.

[0068] (4) Server 1 may change the role of at least one of the client vehicles to a replica vehicle if any of the following conditions 4 to 7 are met, for example. Condition 4. The second period of responsibility has elapsed since the role of the replica vehicle was established. Condition 5. The communication interruption time for the replica vehicle has exceeded the second interruption time. Condition 6. The replica vehicle has moved more than the second escape distance from the area where its role is set. Condition 7. The role of replica vehicles has been changed to that of master vehicles.

[0069] This configuration allows for accurate tracking of the assignment periods and absences of replica vehicles, enabling client vehicles to be upgraded to replica vehicles and facilitating smooth data sharing. For example, it can prevent situations where a specific vehicle (vehicle 2) is continuously forced to take on the role of a replica vehicle, thereby increasing fairness in the rotation. Furthermore, if a replica vehicle is upgraded to a master vehicle, or if a replica vehicle moves outside the area (regional mesh 4) corresponding to network 3, the roles of those replica vehicles can be quickly transferred to client vehicles.

[0070] (5) When selecting a master vehicle, the server 1 can calculate the first cumulative time T1 connected to the network 3 and the second cumulative time T2 in which the vehicle assumed the role of the master vehicle. It can also select a vehicle 2 to which the role of the master vehicle will be assigned based on the value T2 / T1 (ratio T2 / T1) obtained by dividing the second cumulative time T2 by the first cumulative time T1. This makes it possible to distribute the role of the master vehicle more fairly among the vehicles 2 in the network 3 and to make the contribution of each vehicle 2 to the network 3 as a whole nearly uniform.

[0071] (6) Furthermore, when selecting a master vehicle, by considering the deterioration status and communication stability of each vehicle 2, it is possible to achieve both a reduction in the management costs of the vehicles 2 and an improvement in the communication quality within the network 3. For example, within a range that does not place an excessive burden on a particular vehicle 2, the role of the master vehicle can be assigned to a vehicle 2 with good communication quality.

[0072] (7) When selecting a replica vehicle, the server 1 can calculate the first cumulative time T1 connected to network 3 and the third cumulative time T3 in which it assumed the role of a master vehicle or a replica vehicle. It can also select a vehicle 2 to which the role of a replica vehicle will be set based on the value T3 / T1 (ratio T3 / T1) obtained by dividing the third cumulative time T3 by the first cumulative time T1. This makes it possible to distribute the role of a replica vehicle more fairly among the vehicles 2 in network 3 and to make the contribution of each vehicle 2 to network 3 nearly uniform.

[0073] (8) Furthermore, by considering the deterioration status and communication stability of each vehicle 2 when selecting a replica vehicle, it is possible to achieve both a reduction in the management costs of vehicle 2 and an improvement in the communication quality within the network 3. For example, within a range that does not place an excessive burden on a particular vehicle 2, the role of a replica vehicle can be assigned to a vehicle 2 with good communication quality.

[0074] [6. Others] The above embodiments are merely illustrative examples, and there is no intention to exclude various modifications or applications of techniques not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed.

[0075] In the above embodiment, Server 1 assigns and configures one of three roles (master vehicle, replica vehicle, client vehicle) to each vehicle 2, but the configuration of the replica vehicle is optional. By setting the role of the master vehicle to at least one of the vehicles 2 in Network 3 and the role of the client vehicle to the other vehicles 2, a data sharing system that has the same effects as the above embodiment can be realized.

[0076] Furthermore, it is not necessary to assign the role of a client vehicle to all vehicles 2 other than the master vehicle. For example, a vehicle 2 that does not have positioning means 23 or detection means 24 (a vehicle 2 that cannot generate location-related data) may be exempted from the role of a client vehicle and may only receive location-related data provided by the master vehicle. Note that the positioning means 23 is not limited to an in-vehicle navigation system, and the detection means 24 is not limited to an in-vehicle radar system or an in-vehicle video camera system. For example, a smartphone or wearable device owned by the user of vehicle 2 may be used as the positioning means 23 or detection means 24. [Industrial applicability]

[0077] This application is applicable to service industries that provide data sharing systems, and to the manufacturing industry of vehicles to which data sharing systems are applied. [Explanation of Symbols]

[0078] 1 server 2 vehicles 3 Network 4 Regional Mesh 10 Calculation means 11 processors 12 memory 13. Means of communication 14 Memory means 20 Calculation means 21 processors 22 memory 23 Positioning means 24 Detection means 25. Means of communication 26 Memory means

Claims

1. A data sharing system comprising multiple vehicles present in a network and a server that assigns a role to each of the vehicles, and which enables data sharing between the vehicles, The server assigns the role of the first vehicle to one of the vehicles and the role of the second vehicle to the other vehicles. The first vehicle collects and stores a database created from data generated by the second vehicle, and provides the data contained in the database to the second vehicle upon request from the second vehicle. The server assigns the role of a third vehicle, which is neither the first vehicle nor the second vehicle, to at least one of the vehicles. The third vehicle stores a copy of the database stored in the first vehicle. A data sharing system characterized by the following features.

2. The server changes the role of the first vehicle to the second vehicle and changes the role of the third vehicle to the first vehicle if any of the following conditions are met: condition 1 that the first assignment period has elapsed since the role of the first vehicle was assigned; condition 2 that the communication interruption time of the first vehicle is equal to or greater than the first interruption time; or condition 3 that the first vehicle is at least a first departure distance away from the area in which the role of the first vehicle is assigned. A data sharing system according to claim 1, characterized in that...

3. The server changes the role of at least one of the second vehicles to that of the third vehicle if any of the following conditions are met: condition 4 that the second assignment period has elapsed since the role of the third vehicle was assigned; condition 5 that the communication interruption time of the third vehicle is equal to or greater than the second interruption time; condition 6 that the third vehicle is at least a second departure distance away from the area in which the role of the third vehicle is assigned; or condition 7 that the role of the third vehicle is changed to that of the first vehicle. A data sharing system according to claim 1, characterized in that...

4. When the server selects the vehicle to which the role of the first vehicle is assigned, it calculates the first cumulative time during which the vehicle was connected to the network and the second cumulative time during which the vehicle performed the role of the first vehicle, and selects the vehicle based on the value obtained by dividing the second cumulative time by the first cumulative time. A data sharing system according to claim 1, characterized in that...

5. The server determines, based on the vehicle's deterioration status and communication stability, which vehicle will be assigned a role to. A data sharing system according to claim 1, characterized in that...

6. When the server selects the vehicle to which the role of the third vehicle is assigned, it calculates the first cumulative time when the vehicle is connected to the network and the third cumulative time when the vehicle has assumed the role of either the first or third vehicle, and selects the vehicle based on the value obtained by dividing the third cumulative time by the first cumulative time. A data sharing system according to claim 1, characterized in that...

7. The server determines, based on the deterioration status of the vehicle and the communication stability, which vehicle will be assigned a role to. A data sharing system according to claim 1, characterized in that...

8. A data sharing system comprising multiple vehicles present in a network and a server that assigns a role to each of the vehicles, and which enables data sharing between the vehicles, The server assigns the role of a first vehicle to one of the vehicles, assigns the role of a second vehicle to the other vehicles, and assigns the role of a third vehicle to at least one of the vehicles, which is neither the first vehicle nor the second vehicle. The first vehicle stores a database containing data generated by the second vehicle, and provides the data contained in the database to the second vehicle upon request from the second vehicle. The third vehicle stores a copy of the database stored in the first vehicle. A data sharing system characterized by the following features.

9. The server changes the role of the first vehicle to the second vehicle and changes the role of the third vehicle to the first vehicle if any of the following conditions are met: condition 1 that the first assignment period has elapsed since the role of the first vehicle was assigned; condition 2 that the communication interruption time of the first vehicle is equal to or greater than the first interruption time; or condition 3 that the first vehicle is at least a first departure distance away from the area in which the role of the first vehicle is assigned. The data sharing system according to claim 8, characterized in that

10. The server changes the role of at least one of the second vehicles to that of the third vehicle if any of the following conditions are met: condition 4 that the second assignment period has elapsed since the role of the third vehicle was assigned; condition 5 that the communication interruption time of the third vehicle is equal to or greater than the second interruption time; condition 6 that the third vehicle is at least a second departure distance away from the area in which the role of the third vehicle is assigned; or condition 7 that the role of the third vehicle is changed to that of the first vehicle. The data sharing system according to claim 8, characterized in that

11. When the server selects the vehicle to which the role of the third vehicle is assigned, it calculates the first cumulative time when the vehicle is connected to the network and the third cumulative time when the vehicle has assumed the role of either the first or third vehicle, and selects the vehicle based on the value obtained by dividing the third cumulative time by the first cumulative time. The data sharing system according to claim 8, characterized in that

12. The server determines, based on the deterioration status of the vehicle and the communication stability, which vehicle will be assigned a role to. The data sharing system according to claim 8, characterized in that

13. A data sharing system comprising multiple vehicles present in a network and a server that assigns a role to each of the vehicles, and which enables data sharing between the vehicles, The server assigns the role of the first vehicle to one of the vehicles and the role of the second vehicle to the other vehicles. The first vehicle stores a database containing data generated by the second vehicle, and provides the data contained in the database to the second vehicle upon request from the second vehicle. When the server selects the vehicle to which the role of the first vehicle is assigned, it calculates the first cumulative time during which the vehicle was connected to the network and the second cumulative time during which the vehicle performed the role of the first vehicle, and selects the vehicle based on the value obtained by dividing the second cumulative time by the first cumulative time. A data sharing system characterized by the following features.

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