Map data utilization system, utilization method and computer readable storage medium

Abstract

The present invention relates to a map data utilization system, a utilization method, and a computer-readable storage medium. The system of the present invention comprises: a server configured to transmit map data of each of a plurality of areas; and a vehicle having a storage device. When the map data of the area to which the current position of the vehicle belongs is not stored in the storage device, the vehicle transmits an acquisition request for acquiring map data of an acquisition area including at least the area to the server, and stores the map data of the acquisition area transmitted according to the acquisition request in the storage device. When the frequency index value is below a prescribed threshold value, the vehicle erases the map data of the acquisition area from the storage device when a prescribed condition is satisfied, and when the frequency index value is greater than the threshold value, the vehicle maintains the storage of the map data of the acquisition area.

Description

Technical Field

[0001] The present invention relates to a map data utilization system, comprising: a map data distribution server configured to transmit map data of each of a plurality of areas; and a vehicle configured to obtain map data from the map data distribution server and perform predetermined vehicle control based on the obtained map data. Furthermore, the present invention relates to a map data utilization method for controlling a vehicle based on map data obtained from the map data distribution server, and a computer-readable storage medium storing a program for obtaining map data from the map data distribution server. Background Art

[0002] A map data utilization system is known in the past, and the map data utilization system includes: a server configured to send map data to a vehicle; and a vehicle configured to control the vehicle based on the map data sent from the server. For example, in the map data utilization system described in Japanese Patent Application Laid-Open No. 2015-1471 (hereinafter referred to as "the conventional system"), when it is necessary to update the map data stored in the storage device of the vehicle to the latest map data, the vehicle obtains the latest map data from the server in the order of a first area with a high travel frequency, an area adjacent to the first area, and a second area with a low travel frequency.

[0003] The vehicle stores the map data obtained from the server in a storage device provided in the vehicle. In recent years, the accuracy of map data has become increasingly higher. As a result, the amount of map data has increased, and the vehicle therefore requires a storage device with a large storage capacity. However, a storage device with a large storage capacity is expensive, and thus the manufacturing cost of the vehicle ultimately increases. Summary of the invention

[0004] The present invention is made to address the above-mentioned problems. That is, one object of the present invention is to provide a map data utilization system that can reduce the storage capacity required for a storage device by reducing the usage capacity of map data stored in a storage device of a vehicle.

[0005] A map data utilization system of the present invention (hereinafter also referred to as "the system of the present invention") comprises: a map data distribution server (20) configured to transmit map data of each of a plurality of areas having a predetermined size; and a vehicle (VA) equipped with a storage device (36), a position acquisition device (38) and a control device (30 and 60), wherein the storage device (36) stores map data transmitted from the map data distribution server via a network (NW), the position acquisition device (38) acquires a current position, and the control device (30 and 60) performs predetermined vehicle control using the map data stored in the storage device, wherein the map data distribution server is configured to, upon receiving a map data acquisition request transmitted from the vehicle, transmit map data of an area corresponding to the received acquisition request to the vehicle, and wherein the control device is configured to, when map data of an area to which the current position of the vehicle obtained by the position acquisition device belongs among the plurality of areas is not stored in the storage device (step 705 is "No"), transmit a control device for acquiring at least a map data including the current position of the vehicle. The method further comprises: sending a request for obtaining map data of an area to which the position of the vehicle belongs as the acquisition request to the map data distribution server (steps 715 and 725); receiving the map data of the acquisition area sent from the map data distribution server according to the acquisition request and storing the map data in the storage device (steps 800 to 895); when a frequency index value (N) indicating the frequency of the vehicle traveling in the area to which the position of the vehicle belongs when the acquisition request is sent is less than a predetermined erasure threshold value (N2th) (step 740 is "Yes (Yes ( )”, step 725, step 810 is “Yes”, step 815), when a specified erasure condition is met, the map data of the acquisition area is erased from the storage device (step 920); and when the frequency index value of the area to which the position of the vehicle when the acquisition request is sent belongs is greater than the erasure threshold (step 740 is “No”, step 750, step 810 is “No”), regardless of whether the erasure condition is met, the storage of the map data of the acquisition area is maintained, and the map data of the acquisition area is not erased from the storage device (step 820).

[0006] According to the system of the present invention, when the frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is less than the erasure threshold, if the erasure condition is satisfied, the map data sent from the map data distribution server in response to the acquisition request is erased from the storage device. As a result, the usage capacity of the map data stored in the storage device can be reduced, and thus the storage capacity requested for the storage device can be reduced. Furthermore, since the map data of the area whose frequency index value is greater than the erasure threshold is not erased from the storage device, it is not necessary to obtain the map data of the area from the map data distribution server multiple times. As a result, the communication volume between the map data distribution server and the vehicle can be reduced.

[0007] In one embodiment of the system of the present invention, the control device is configured to: when the frequency index value (N) of the area to which the current position of the vehicle belongs is greater than a prescribed acquisition threshold (N1th) (step 730 is "Yes"), send a first acquisition request as the acquisition request to the map data distribution server (step 735), wherein the first acquisition request is a request for obtaining map data of the area to which the current position of the vehicle belongs; and when the frequency index value of the area to which the current position of the vehicle belongs is below the acquisition threshold (step 730 is "No"), send a second acquisition request as the acquisition request to the map data distribution server (step 715), wherein the second acquisition request is a request for obtaining map data of the area to which the current position of the vehicle belongs and an area adjacent to the area to which the current position of the vehicle belongs.

[0008] When a vehicle enters an area where the frequency index value is below the acquisition threshold (hereinafter referred to as a "low-frequency area"), the possibility of passing through an area where map data is not stored in the storage device is high compared to a case where the vehicle enters an area where the frequency index value is greater than the acquisition threshold (hereinafter referred to as a "high-frequency area") . This is because when the vehicle enters a low-frequency area, it is highly likely that the vehicle is traveling toward a destination with a low visit frequency or a destination visited for the first time. In this scheme, if the frequency index value of the area to which the current position of the vehicle belongs is below the acquisition threshold, map data of the area to which the current position of the vehicle belongs and map data of areas adjacent to the area are acquired. As a result, even if the vehicle enters another low-frequency area after entering a low-frequency area, the possibility of performing vehicle control based on map data of the entry destination without acquiring map data of the area of ​​the entry destination from the map data distribution server can be increased.

[0009] In the above scheme, the control device is configured to: when the frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is below the specified erasure threshold, when the area to which the current position of the vehicle belongs becomes different from the area to which the position of the vehicle belonged when the first acquisition request was sent (step 915 is "No"), determine that the erasure condition is met, and erase the map data sent from the map data distribution server according to the first acquisition request from the storage device (step 920); when the area to which the current position of the vehicle belongs becomes different from the area to which the position of the vehicle belongs when the second acquisition request was sent and the area adjacent to the area to which the position of the vehicle belonged when the second acquisition request was sent (step 925 is "No"), determine that the erasure condition is met, and erase the map data sent from the map data distribution server according to the second acquisition request from the storage device (step 920).

[0010] When the area to which the current position of the vehicle belongs is different from the area to which the position of the vehicle belonged when the first acquisition request was sent, the map data sent from the map data distribution server according to the first acquisition request is not used. When the area to which the current position of the vehicle belongs is different from the area to which the position of the vehicle belonged when the second acquisition request was sent and the area adjacent to the area to which the position of the vehicle belonged when the second acquisition request was sent, the map data sent from the map data distribution server according to the second acquisition request is not used. According to this scheme, when the erasure condition is satisfied when the map data is not used, the map data is erased from the storage device. This can effectively reduce the usage capacity of the map data of the storage device.

[0011] In one embodiment of the system of the present invention, the ratio of the number of passes to the number of drives and either the number of passes are obtained as the frequency index value (step 620), wherein the number of passes is the number of times the vehicle passes through the area within the specified period, and the number of drives is the number of times the vehicle is driven within the specified period.

[0012] Thus, the frequency index value indicates the travel frequency of each area of ​​the "vehicle". Therefore, only the map data of the area whose frequency index value indicating the travel frequency of the "vehicle" is greater than the erasure threshold is stored in the storage device. Thus, the storage capacity of the map data in the storage device can be reduced.

[0013] In one embodiment of the system of the present invention, the ratio of the number of passes to the number of driving times and either one of the number of passes are obtained as the frequency index value (step 1115), wherein the number of passes is the number of times the vehicle driven by the current driver who is the driver of the vehicle at the current time point passes through the area within a specified period, and the number of driving times is the number of times the vehicle is driven by the current driver within the specified period.

[0014] Thus, the frequency index value indicates the travel frequency of each area "for each driver". Therefore, only the map data of the area whose frequency index value indicating the travel frequency of the driver is greater than the erasure threshold value is stored in the storage device. Thus, the storage capacity of the map data in the storage device can be reduced, and the map data corresponding to the travel frequency of the driver can be stored in the storage device.

[0015] In one embodiment of the system of the present invention, a ratio of the number of passes to the number of driving times is obtained as a first frequency index value, wherein the number of passes is the number of times the vehicle driven by the current driver who is the driver of the vehicle at the current time point passes through the area within a specified period, and the number of driving times is the number of times the vehicle driven by the current driver is driven within the specified period, and a ratio of the number of passes to the number of driving times is obtained as a second frequency index value, wherein the number of passes is the number of times the vehicle passes through the area without distinguishing the driver of the vehicle within the specified period, and the number of driving times is the number of times the vehicle is driven without distinguishing the driver within the specified period, and the control device is configured to: when the first frequency index value of the area to which the current position of the vehicle belongs is greater than a specified acquisition threshold value ( Fig.13 Step 1210 shown in the figure is "yes"), sending the first acquisition request as the acquisition request to the map data distribution server ( Fig.13 Step 735 shown in the figure), wherein the first acquisition request is a request for acquiring map data of an area to which the current position of the vehicle belongs; when the first frequency index value of the area to which the current position of the vehicle belongs is less than the acquisition threshold value ( Fig.13 Step 1210 shown in the figure is "No"), sending the second acquisition request as the acquisition request to the map data distribution server ( Fig.13 The second acquisition request is a request for acquiring map data of an area to which the current position of the vehicle belongs and an area adjacent to the area to which the current position of the vehicle belongs; if the second frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is less than the erasure threshold value (step 1310 is "yes", Fig.13In the case where the second frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is greater than the erasure threshold value (step 1310 is "No", step 1325 is "No", step 1330 is "No", step 1340 is "No", step 1350 is "No", step 1360 is "No", step 1370 is "No", step 1380 is "No", step 1390 is "No", step 1400 is "No", step 1410 is "No", step 1420 is "No", step 1430 is "No", step 1440 is "No", step 1450 is "No", step 1460 is "No", step 1470 is "No", step 1480 is "No", step 1490 is "No", step 1500 is "No", step 1510 is "No", step 1520 is "No", Fig.13 If the answer of step 750 and step 810 is “No”, the storage of the map data of the acquisition area is maintained (step 820).

[0016] When the vehicle enters a low-frequency area where the current driver's driving frequency (first frequency index value) is below the acquisition threshold, there is a high possibility that the vehicle will subsequently pass through an area where the driver's driving frequency is low and map data is not stored in the storage device. In this case, map data of the area to which the current position of the vehicle belongs and map data of areas adjacent to the area are acquired.

[0017] Moreover, according to this scheme, even if the driver's driving frequency (first frequency index value) is high, map data of areas where the vehicle's driving frequency (second frequency index value) is low is erased from the storage device regardless of the driver, thereby reducing the storage capacity of the map data in the storage device.

[0018] The map data utilization method of the present invention is as follows: map data sent from a map data distribution server (20) to a vehicle (VA) via a network (NW) is stored in a storage device (36) provided in the vehicle, and prescribed vehicle control is performed using the map data stored in the storage device, wherein the map data distribution server (20) stores map data of each of a plurality of areas having prescribed sizes, the map data utilization method comprising: a first step (step 715 and step 725), in which, when the map data of the area to which the current position of the vehicle belongs is not stored in the storage device (step 705 is "No"), a request for obtaining map data of an acquisition area including at least the area to which the current position of the vehicle belongs is sent to the map data distribution server; and a second step (steps 800 to 895), in which a request is received from the map data distribution server according to the request. a first step (step 920) in which, when a frequency index value (N) indicating the frequency of the vehicle traveling in the area to which the position of the vehicle when the request is sent is equal to or less than a prescribed erasure threshold value (N2th) ("Yes" in step 740, "Yes" in step 725 and step 810, and "Yes" in step 815), the map data of the acquisition area is erased from the storage device when a prescribed erasure condition is satisfied; and a second step (step 820) in which, when the frequency index value of the area to which the position of the vehicle when the request is sent is greater than the erasure threshold value ("No" in step 740, "No" in step 750 and step 810), the map data of the acquisition area is maintained stored, and the map data of the acquisition area is not erased from the storage device, regardless of whether the erasure condition is satisfied.

[0019] A program stored in a computer-readable storage medium of the present invention is applied to a vehicle (VA), the vehicle (VA) having a storage device (36) for storing map data sent from a map data distribution server (20) via a network (NW), and using the map data stored in the storage device to perform prescribed vehicle control, wherein the map data distribution server stores map data for each of a plurality of areas having prescribed sizes, the program comprising: a first step (steps 715 and 725), in which, when the map data for the area to which the current position of the vehicle belongs is not stored in the storage device (step 705 is "No"), a request for obtaining map data for an acquisition area including at least the area to which the current position of the vehicle belongs is sent to the map data distribution server; and a second step (steps 800 to 895), in which a request is received from the map data distribution server according to the request. The map data of the acquisition area sent and the map data are stored in the storage device; a third step (step 920), when the frequency index value (N) indicating the frequency of the vehicle traveling in the area to which the position of the vehicle when the request is sent belongs is less than a prescribed erasure threshold value (N2th) (step 740 is "yes", step 725, step 810 is "yes", step 815), the map data of the acquisition area is erased from the storage device when a prescribed erasure condition is satisfied; and a fourth step (step 820), when the frequency index value of the area to which the position of the vehicle when the request is sent belongs is greater than the erasure threshold value (step 740 is "no", step 750, step 810 is "no"), regardless of whether the erasure condition is satisfied, the storage of the map data of the acquisition area is maintained, and the map data of the acquisition area is not erased from the storage device.

[0020] According to the map data acquisition method and the program, when the frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is less than the erasure threshold, if the erasure condition is satisfied, the map data sent from the map data distribution server in response to the acquisition request is erased from the storage device. Thus, the usage capacity of the map data stored in the storage device of the vehicle can be reduced.

[0021] It should be noted that, in the above description, in order to help understand the invention, the names and / or figure marks used in the embodiments described below are added in brackets to the configuration of the invention corresponding to the embodiments described later. However, the various constituent elements of the invention are not limited to the embodiments specified by the names and / or figure marks. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0023] Figure 1 This is a schematic system configuration diagram of a map data utilization system according to an embodiment of the present invention.

[0024] Figure 2 This is an illustration of the map data.

[0025] Figure 3 yes Figure 1 A schematic system configuration diagram of a vehicle shown.

[0026] Figure 4 yes Figure 3 An illustration of a storage device of a vehicle is shown.

[0027] Figure 5 This is a diagram illustrating the travel frequency of each area.

[0028] Figure 6 Yes means Figure 3 Flowchart of a map data management routine executed by the CPU of the control ECU shown.

[0029] Figure 7 Yes means Figure 3 Flowchart of a map data acquisition subroutine executed by the CPU of the control ECU shown.

[0030] Figure 8 Yes means Figure 3 Flowchart of a map data storage routine executed by the CPU of the control ECU shown.

[0031] Fig. 9 Yes means Figure 3 Flowchart of a map data erasing subroutine executed by the CPU of the control ECU shown.

[0032] Fig.10 Yes means Figure 3 Flowchart of a vehicle control routine executed by the CPU of the control ECU shown.

[0033] Fig.11 This is a flowchart showing a map data management routine according to a first modified example of the embodiment of the present invention.

[0034] Fig.12 1 is a flowchart showing a map data acquisition subroutine according to a first modified example of the embodiment of the present invention.

[0035] Fig.13 1 is a flowchart showing a map data acquisition subroutine according to a second modified example of the embodiment of the present invention. DETAILED DESCRIPTION

[0036] Hereinafter, a map data utilization system (hereinafter referred to as "this system") 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown in FIG. 1 , the system 10 includes a map data distribution server 20 and a vehicle VA. Hereinafter, the map data distribution server 20 is referred to as the “distribution server 20”. Figure 1 Although only one vehicle VA is shown in FIG. 1 , the system 10 may include a plurality of vehicles VA. The vehicle VA is connected to the distribution server 20 via the network NW so as to be able to perform data communication with the distribution server 20 .

[0037] The distribution server 20 includes a CPU, ROM, RAM, an interface (I / F), and a storage device 22. The CPU implements various functions by executing instructions (routines) stored in the memory (ROM). The storage device 22 is composed of, for example, a hard disk and has a map data storage unit 220 storing map data.

[0038] like Figure 2 As shown, the map data is divided into data corresponding to a plurality of areas AR. The map data is stored in the map data storage unit 220 in a manner that enables identification of which area of ​​the plurality of areas AR the map data belongs to. The area AR is divided (defined) by a plurality of parallel lines Lx in the X direction and a plurality of parallel lines Ly in the Y direction. In this example, the area AR is a square having a mutually equal size. As an example, the length d0 of one side of the area AR is 1 km. It should be noted that the shape of the area AR may not be a square.

[0039] In this example, the X direction is the east direction of the azimuth, and the Y direction is the direction perpendicular to the X direction (i.e., the north direction). The positions of the region AR in the X direction and the Y direction are represented by the values ​​Xk (k=1, 2, 3...L) and the values ​​Ym (m=1, 2, 3...N). One of the multiple regions AR is determined by the data set (Xk, Ym). That is, the data set (Xk, Ym) of the values ​​Xk and the values ​​Ym is an area identifier (area ID) that can uniquely identify the region AR. The range of each of the multiple regions AR is specified by latitude and longitude. Therefore, when the position information determined by a certain latitude and longitude set is given, one region (Xk, Ym) is determined from the multiple regions AR.

[0040] like Figure 3 As shown, the vehicle VA includes a control ECU 30 and a steering ECU 60. These ECUs are connected to each other via a CAN (Controller Area Network) so as to be data communicable.

[0041] ECU is the abbreviation of electronic control unit, which is an electronic control circuit having a microcomputer including a CPU, ROM, RAM, a writable non-volatile memory (in this case, EEPROM) and an interface as its main components. ECU is sometimes called a "control device" or "controller". The CPU implements various functions by executing instructions (routines) stored in the memory (ROM). All or some of the above-mentioned ECUs 30 and 60 can also be integrated into one ECU.

[0042] Furthermore, the vehicle VA includes a driver's seat camera device 32, a GNSS (Global Navigation Satellite System) receiver 34, a storage device 36, and a data communication device 38. These are connected to the control ECU 30 in a data-communicable manner.

[0043] The driver seat camera device 32 acquires an image of the vicinity of the driver seat of the vehicle VA (driver seat image), and transmits the driver seat image to the control ECU 30. The driver seat camera device 32 is used in the first modification.

[0044] The GNSS receiver 34 receives “signals from artificial satellites (GNSS signals)” for detecting the current position (latitude, longitude) of the vehicle VA. Hereinafter, the GNSS receiver 34 may also be referred to as a “position acquisition device”.

[0045] The storage device 36 is a device including a storage medium (such as a hard disk) that can write, store, and read data. Figure 4 As shown, the storage device 36 includes a map data storage unit 360 and a temporary storage unit 362. The map data stored in the temporary storage unit 362 is erased when an erase condition described later is satisfied, but the map data stored in the map data storage unit 360 is not erased even if the erase condition is satisfied.

[0046] Figure 3 The illustrated data communication device 38 includes a wireless communication device configured to be able to exchange data between the control ECU 30 and the distribution server 20 .

[0047] The steering ECU 60 is a well-known control device for an electric power steering system, and is connected to a steering angle sensor 62 and a steering motor 64. The steering motor 64 is assembled in a "steering mechanism (not shown) including a steering wheel, a steering shaft (not shown) connected to the steering wheel, and a steering gear mechanism (not shown)" of the vehicle VA.

[0048] The steering angle sensor 62 detects a steering angle θ of a steering wheel of the vehicle VA, and outputs a detection signal indicating the steering angle θ to the steering ECU 60 .

[0049] The steering motor 64 generates torque based on the electric power whose direction and size are controlled by the steering ECU 60, and applies steering assist torque or steers the left and right steering wheels by the torque. That is, the steering ECU 60 can control the steering angle θ using the steering motor 64. It should be noted that the above-mentioned electric power is supplied from a battery (not shown) mounted on the vehicle VA.

[0050] The control ECU 30 determines the current position (the position of the vehicle VA at the current time point) based on the GNSS signal received by the GNSS receiver 34. The control ECU 30 determines the area ID of the current area (hereinafter referred to as "current area ID (Xk, Ym)" or "current area ID") which is the area corresponding to the current position by referring to the area ID management data pre-stored in the ROM. The correspondence between the latitude and longitude and Xk and Ym is registered in the area ID management data. Then, the control ECU 30 reads the map data corresponding to the current area ID (Xk, Ym) (hereinafter referred to as "current map data") from the storage device 36, and performs the prescribed vehicle control based on the current map data.

[0051] Here, there is automatic steering control as an example of vehicle control performed by the control ECU 30. In this automatic steering control, the control ECU 30 controls the steering angle θ so that the vehicle VA travels at a predetermined position near the center in the width direction of the lane in which it is currently traveling.

[0052] More specifically, the control ECU 30 sends a steering command signal including a target steering angle θtgt for the vehicle VA to pass the predetermined position to the steering ECU 60. The steering ECU 60 controls the steering motor 64 so that the steering angle θ matches the target steering angle θtgt included in the steering command signal.

[0053] (Work Summary)

[0054] The control ECU 30 determines the current position every predetermined time, and determines the current area ID based on the current position. The current area ID determined at the current time point is called the "current current area ID", and the current area ID determined a predetermined time ago from the current time point is called the "previous area ID". If the area where the vehicle VA is traveling is switched to a new area between the determination of the previous area ID and the determination of the current current area ID, the current current area ID is different from the previous area ID.

[0055] When the current area ID has changed from the previous area ID, if the map data corresponding to the current area ID is not stored in the map data storage unit 360, the control ECU 30 sends an "acquisition request for acquiring map data" containing at least "map data corresponding to the current area ID" to the distribution server 20 via the data communication device 38. The acquisition request contains the area ID of the map data that the control ECU 30 wants to acquire (hereinafter referred to as the "request area ID"). When the distribution server 20 receives the acquisition request from the vehicle VA, it sends the map data corresponding to the area ID included in the acquisition request to the vehicle VA. It should be noted that the area of ​​the map data acquired through the acquisition request is sometimes referred to as the "acquisition area".

[0056] Furthermore, the control ECU 30 calculates and stores the travel frequency N of each area of ​​the vehicle VA within a predetermined period (for example, three months). More specifically, the control ECU 30 obtains the travel frequency N by dividing the number of times SN of the areas that the vehicle VA passes through within the predetermined period by the number of times D the vehicle is driven within the predetermined period. The number of times D is the number of trips counted as one when an ignition key switch (a switch for enabling vehicle driving) of the vehicle VA (not shown) is changed from the off position to the on position and then from the on position to the off position.

[0057] When the vehicle VA (data communication device 38) receives the map data from the distribution server 20, the control ECU 30 determines whether the travel frequency N of the area corresponding to the current area ID is greater than the prescribed erasure threshold. When the travel frequency N of the area corresponding to the current area ID is greater than the prescribed erasure threshold, the control ECU 30 stores the received map data in the map data storage unit 360. On the other hand, when the travel frequency N of the area corresponding to the current area ID is less than the prescribed erasure threshold, the control ECU 30 stores the received map data in the temporary storage unit 362. Then, the control ECU 30 reads the map data corresponding to the current area ID stored in either the map data storage unit 360 or the temporary storage unit 362 to the RAM, and performs vehicle control based on the map data read to the RAM.

[0058] When a predetermined erasure condition is satisfied, the control ECU 30 erases the map data stored in the temporary storage unit 362 from the temporary storage unit 362. The erasure condition of the present embodiment includes at least the condition that the current area ID is different from the area ID when the acquisition request was transmitted.

[0059] Thus, only the map data of the area where the travel frequency N is greater than the erasure threshold is stored (stored) in the storage device 36 without being erased, so that the storage capacity of the map data for the storage device 36 can be reduced compared to the case where the map data of all areas are stored in the storage device 36. In addition, once the map data of the area where the travel frequency N is greater than the erasure threshold is acquired, the control ECU 30 does not need to acquire the map data again, so the communication volume from the distribution server 20 to the vehicle VA can also be reduced.

[0060] (Working Example)

[0061] When sending an acquisition request, if the travel frequency N of the area with the current area ID is greater than a predetermined acquisition threshold, control ECU 30 sends an acquisition request with the acquisition request ID being the current area ID. Hereinafter, such an acquisition request is referred to as a "first acquisition request".

[0062] On the other hand, when the above-mentioned driving frequency N is below the acquisition threshold, the control ECU 30 sends an acquisition request whose acquisition request ID is the current area ID and "the area ID of the area adjacent to the current area (hereinafter referred to as "adjacent area ID")". Hereinafter, such an acquisition request will be referred to as a "second acquisition request". Which area is adjacent to the current area will be described later.

[0063] It should be noted that the acquisition threshold is set to a value smaller than the erasure threshold. Hereinafter, the acquisition threshold is referred to as a "first threshold N1th", and the erasure threshold is referred to as a "second threshold N2th" (N1th<N2th).

[0064] The area is classified into any one of the first area to the third area described below according to the relationship between the travel frequency of each area and each of the first threshold value N1th and the second threshold value N2th.

[0065] First region: a region where the travel frequency N is equal to or less than a first threshold value N1th (N≤N1th).

[0066] Second region: a region where the travel frequency N is greater than the first threshold value N1th and is equal to or less than the second threshold value N2th (N1th<N≤N2th).

[0067] Third region: a region where the travel frequency N is greater than the second threshold value N2th (N2th<N).

[0068] exist Figure 5 In the example shown, the first area is a white area that is not filled, the second area is a shaded area, and the third area is an area filled with a dark color.

[0069] exist Figure 5In the example shown, the areas through which the two paths R1 and R2 indicated by the bold lines pass are both third areas. Path R1 is a path from one's home to the workplace, and path R2 is a path from one's home to the supermarket. Path R1 and path R2 are a common path from one's home to a certain location, and diverge from the certain location. When the vehicle VA passes through these areas and the travel frequency is greater than the second threshold (that is, when the area becomes the third area), the map data of these areas received from the distribution server 20 is stored in the map data storage unit 360.

[0070] Afterwards, when the vehicle VA enters the third area, the map data of the third area is stored in the map data storage unit 360, so the control ECU 30 does not need to obtain the map data from the distribution server 20. As a result, it is not necessary to obtain map data of areas on routes with high travel frequency such as routes R1 and R2 from the distribution server 20, so the communication volume between the vehicle VA and the distribution server 20 can be reduced.

[0071] When the vehicle VA enters the second area, if the map data of the second area is not stored in the temporary storage unit 362 , the control ECU 30 transmits a first acquisition request to the distribution server 20 .

[0072] When the vehicle VA enters the first area, if the map data of the first area is not stored in the temporary storage unit 362 , the control ECU 30 transmits a second acquisition request to the distribution server 20 .

[0073] like Figure 5 As shown by arrow A1, when the vehicle VA enters the first area (X3, Y3) from the third area (X4, Y3), the map data of the first area (X3, Y3) is neither stored in the map data storage unit 360 nor in the temporary storage unit 362. In this case, the control ECU 30 sends a second acquisition request whose acquisition request ID is the ID of "the first area (X3, Y3) entered by the vehicle VA" and "the following adjacent areas" to the distribution server 20.

[0074] Adjacent regions: (X2, Y2), (X2, Y3), (X3, Y2), and (X4, Y2)

[0075] The adjacent area is an area adjacent to the area (X3, Y3) entered by the vehicle VA in a manner that surrounds the area (X3, Y3), except for the area (X4, Y3) where the vehicle VA was located before entering the area (X3, Y3) and the areas where the vehicle VA has map data stored in the map data storage unit 360 ((X2, Y4), (X3, Y4) and (X4, Y4)).

[0076] When receiving the map data of these areas, the control ECU 30 stores the map data in the temporary storage unit 362 .

[0077] Thereafter, as indicated by arrow A2, when the vehicle VA enters the first area (X2, Y3) from the first area (X3, Y3), the map data of the first area (X2, Y3) is stored in the temporary storage unit 362. In this case, the control ECU 30 sends neither the first acquisition request nor the second acquisition request.

[0078] When the vehicle VA enters the first area, there is a high possibility that the vehicle VA is traveling toward a destination with low visit frequency or a destination visited for the first time, compared with the case where the vehicle VA enters any of the second area and the third area. Therefore, there is a high possibility that the vehicle VA enters "an area where map data is neither stored in the map data storage unit 360 nor in the temporary storage unit 362" after entering the first area. Therefore, when the vehicle VA enters the first area, the control ECU 30 also obtains the map data of the adjacent area in advance. Thus, even if the vehicle VA enters an area adjacent to the first area immediately after entering the first area, the vehicle control is immediately performed based on the map data of the adjacent area.

[0079] (Specific work)

[0080] <Map data management routine>

[0081] The CPU of the control ECU 30 (hereinafter, when it is marked as "CPU", it means the CPU of the control ECU 30 unless otherwise specified) executes the Figure 6 The map data management routine shown in the flowchart is a map data management program stored in the ROM of the control ECU 30.

[0082] Therefore, when the predetermined timing is reached, the CPU Figure 6 The process starts at step 600, and the processes of "step 605 to step 615" described below are performed in sequence.

[0083] Step 605 : The CPU obtains the current position of the vehicle VA based on the GNSS signal received by the GNSS receiver 34 .

[0084] Step 610: The CPU refers to the area ID management data and determines the current area ID corresponding to the current position as the current area ID.

[0085] Step 615: The CPU determines whether the current area ID is the same as the previous area ID. It should be noted that the previous area ID is the current area ID obtained when this routine was executed last time (before a specified time) (see step 635 described later).

[0086] When the current area ID is different from the previous area ID (i.e., the vehicle VA has entered an area different from the area with the previous area ID), the CPU determines as "No" in step 615 and executes the processing of "steps 620 to 635" described below in sequence.

[0087] Step 620: The CPU obtains the travel frequency N of the area specified by the current area ID (hereinafter referred to as the "current area").

[0088] More specifically, the CPU adds "1" to the "number of times the vehicle passes through the current area SN" stored in the EEPROM at the current time point to update the number of times the vehicle passes through the current area, and divides the updated number of times the vehicle passes through the current area SN by the number of times the vehicle drives the current area D, thereby obtaining the travel frequency N of the current area (N = SN / D). It should be noted that in the initialization routine executed by the CPU when the ignition key switch (not shown) of the vehicle VA is changed from the off position to the on position, the CPU adds "1" to the number of times the vehicle drives the current area D, and stores the added value in the EEPROM. Furthermore, the CPU stores the updated travel frequency N of the current area in the EEPROM.

[0089] Step 625: The CPU executes a map data acquisition subroutine for acquiring map data from the distribution server 20. In fact, when entering step 625, the CPU executes Figure 7 The processing in the subroutine will be described in detail later. The CPU sends the first acquisition request or the second acquisition request to the distribution server 20 as needed.

[0090] Step 630: When the predetermined erasing condition is satisfied, the CPU executes a map data erasing subroutine for erasing the map data stored in the temporary storage unit 362. Fig. 9 The processing in this subroutine will be described in detail later.

[0091] Step 635: The CPU makes the previous area ID consistent with the current area ID acquired in step 610. That is, the CPU stores the current area ID as the previous area ID in the RAM.

[0092] Afterwards, the CPU enters step 695 to temporarily terminate this routine.

[0093] When the CPU enters step 615, if the current area ID is the same as the previous area ID (that is, if the vehicle VA is traveling in the same area as when the present routine was last executed), the CPU makes a "yes" determination in step 615. Then, the CPU directly enters step 630 from step 615 and executes the processing of steps 630 and 635 described above.

[0094] <Map data acquisition subroutine>

[0095] When entering Figure 6 At step 625, the CPU Figure 7 The process starts at step 700 and proceeds to step 705 . At step 705 , the CPU determines whether the map data of the current area is stored in any one of the map data storage unit 360 and the temporary storage unit 362 .

[0096] When the map data of the current area is not stored in the map data storage unit 360 or the temporary storage unit 362, the CPU determines "No" in step 705 and proceeds to step 710. In step 710, the CPU determines whether the driving frequency D is greater than a predetermined threshold value Dth.

[0097] When the driving frequency D is less than the threshold value Dth, the CPU determines "No" in step 710 and sequentially executes the processing of "step 715 and step 725" described below. Thereafter, the CPU enters step 795 to temporarily end this routine and enters Figure 6 Step 630 is shown.

[0098] Step 715 : The CPU sends a second acquisition request to the distribution server 20 .

[0099] The acquisition request ID of the second acquisition request is the following area ID, and the second acquisition request includes the vehicle ID which is an identifier that can uniquely identify the vehicle VA.

[0100] The current region ID, which is the ID of the current region

[0101] Area IDs of areas adjacent to the current area so as to surround the current area (except for areas specified by the previous area ID and areas for which map data is stored in the map data storage unit 360 and the temporary storage unit 362)

[0102] The distribution server 20 transmits the "map data and area ID" corresponding to the acquisition request ID of the second acquisition request to the vehicle VA. Upon receiving the data, the vehicle VA stores the data. The storage method will be described later.

[0103] Step 725: The CPU sets the erase flag Xdel to "1".

[0104] It should be noted that the erase flag Xdel is set to "0" in the above initialization routine.

[0105] When the number of driving times D is greater than the threshold value Dth when the CPU enters step 710, the CPU makes a "yes" determination in step 710 and proceeds to step 730. In step 730, the CPU determines whether the travel frequency N in the current area is greater than the first threshold value N1th.

[0106] When the travel frequency N of the current area is less than the first threshold value N1th (i.e., when the current area is the first area), the CPU determines "No" in step 730, and after sequentially executing the processing of "step 715 and step 725" described above, enters Figure 6 Step 630 is shown. Thus, the CPU sends the second acquisition request to the distribution server 20.

[0107] On the other hand, when the travel frequency N in the current area is greater than the first threshold value N1th, the CPU makes a “Yes” determination in step 730 , and sequentially executes the processes of “step 735 and step 740 ” described below.

[0108] Step 735 : The CPU sends the first acquisition request to the distribution server 20 .

[0109] The acquisition request ID of the first acquisition request is the current area ID, and the first acquisition request includes the vehicle ID.

[0110] The distribution server 20 sends the "map data and area ID (in this case, the current area ID)" corresponding to the acquisition request ID of the first acquisition request to the vehicle VA. Upon receiving the data, the vehicle VA stores the data. The storage method will be described later.

[0111] Step 740: The CPU determines whether the travel frequency N in the current area is less than or equal to the second threshold value N2th.

[0112] When the current area's travel frequency N is less than the second threshold value N2th (i.e., when the current area is the second area), the CPU determines "yes" in step 740 and proceeds to step 725 to set the erase flag Xdel to "1". Thereafter, the CPU proceeds to step 795 to temporarily terminate this routine and proceed to step 796. Figure 6 Step 630 is shown.

[0113] On the other hand, when the current area's travel frequency N is greater than the second threshold value N2th (i.e., when the current area is the third area), the CPU determines "No" in step 740 and proceeds to step 750 to set the erase flag Xdel to "0". Thereafter, the CPU proceeds to step 795 to temporarily terminate this routine and proceed to step 797. Figure 6 Step 630 is shown.

[0114] Furthermore, when the map data of the current area is stored in either the map data storage unit 360 or the temporary storage unit 362 when the CPU proceeds to step 705 , the CPU makes a “yes” determination in step 705 and proceeds to step 740 .

[0115] As described above, when the map data of the current area is not stored in either the map data storage unit 360 or the temporary storage unit 362,

[0116] (1) When the current area is any one of the second area and the third area (step 730: Yes), the CPU sends a first acquisition request to the distribution server 20 (step 735),

[0117] (2) When the current area is the first area (step 730 : No), the CPU sends a second acquisition request to the distribution server 20 (step 715 ).

[0118] Furthermore, when the current area is any one of the first area and the second area, the CPU sets the erase flag Xdel to "1" (step 725). When the current area is the third area, the CPU sets the erase flag Xdel to "0" (step 750).

[0119] <Map data storage routine>

[0120] Furthermore, with Figure 6 Unlike the map data management routine shown, the CPU executes the Figure 8 The map data storage routine shown by the flowchart in FIG.

[0121] Therefore, when the predetermined timing is reached, the CPU Figure 8 The process starts at step 800 and proceeds to step 805 to determine whether the vehicle VA (data communication device 38 ) has received the map data from the distribution server 20 .

[0122] When the vehicle VA has not received the map data, the CPU makes a "No" determination in step 805 and proceeds to step 895 to temporarily terminate this routine.

[0123] When the vehicle VA receives the map data, the CPU determines "yes" in step 805 and proceeds to step 810. In step 810, the CPU determines whether the value of the erase flag Xdel is "1". As described above, the value of the erase flag Xdel is set to "1" when the current area is any one of the first area and the second area, and is set to "0" when the current area is the third area.

[0124] When the value of the erase flag Xdel is "1" (i.e., when the current area is any one of the first area and the second area), the CPU determines "yes" in step 810 and proceeds to step 815 to store the received map data in the temporary storage unit 362. When the received map data is map data sent from the distribution server 20 in accordance with the first acquisition request (hereinafter referred to as "first map data"), the CPU also stores information indicating that the map data is the first map data in the temporary storage unit 362. On the other hand, when the received map data is map data sent from the distribution server 20 in accordance with the second acquisition request (hereinafter referred to as "second map data"), the CPU also stores information indicating that the map data is the second map data in the temporary storage unit 362. Thereafter, the CPU proceeds to step 895 to temporarily end this routine.

[0125] On the other hand, when the value of the erase flag Xdel is "0" (i.e., when the current area is the third area), the CPU determines "No" in step 810 and proceeds to step 820 to store the received map data in the map data storage unit 360. Thereafter, the CPU proceeds to step 895 to temporarily terminate this routine.

[0126] <Map data erasing subroutine>

[0127] The CPU erases the data stored in this way as follows. That is, when entering Figure 6 At step 630 shown, the CPU Fig. 9 The process starts at step 900 and proceeds to step 905 . At step 905 , the CPU determines whether map data is stored in the temporary storage unit 362 .

[0128] If no map data is stored in the temporary storage unit 362, the CPU determines "No" in step 905, proceeds to step 995 to temporarily terminate this routine, and proceeds to step 997. Figure 6 Step 635 is shown.

[0129] On the other hand, when the map data is stored in the temporary storage unit 362, the CPU makes a "yes" determination in step 905 and proceeds to step 910. In step 910, the CPU determines whether the map data stored in the temporary storage unit 362 is the first map data.

[0130] In the case where the map data stored in the temporary storage unit 362 is the first map data, the CPU determines "yes" in step 910 and proceeds to step 915. In step 915, the CPU determines whether the current area ID is the same as the area ID of the first map data stored in the temporary storage unit 362. It should be noted that the area ID of the first map data is the current area ID when the first acquisition request is sent, wherein the first acquisition request is a request for requesting the acquisition of the first map data. The current area ID when such an acquisition request for requesting the acquisition of map data is sent is called the "area ID at the time of acquisition".

[0131] If the current area ID is the same as the area ID at the time of acquisition (i.e., if the vehicle VA is traveling in the area of ​​the first map data), the CPU determines "yes" in step 915, proceeds to step 995 to temporarily terminate this routine, and proceeds to step 997. Figure 6 Step 635 is shown.

[0132] On the other hand, when the current area ID is different from the area ID at the time of acquisition (i.e., when the vehicle VA is traveling in an area different from the area of ​​the first map data), the CPU determines "No" in step 915 and proceeds to step 920. In step 920, the CPU erases the first map data from the temporary storage unit 362. Thereafter, the CPU proceeds to step 995 to temporarily terminate this routine and proceed to step 996. Figure 6 Step 635 is shown.

[0133] On the other hand, when the CPU enters step 910, if the map data stored in the temporary storage unit 362 is not the first map data, the map data stored in the temporary storage unit 362 is the second map data. The second map data is the map data of the current area when the second acquisition request is sent and the map data of the adjacent area of ​​the current area.

[0134] When the map data stored in the temporary storage unit 362 is the second map data, the CPU determines "No" in step 910 and proceeds to step 925. In step 925, the CPU determines whether the current area ID is the same as any one of the area IDs of the second map data stored in the temporary storage unit 362 (i.e., the area ID at the time of acquisition and the adjacent area ID adjacent to the area of ​​the area ID at the time of acquisition).

[0135] If the current area ID is the same as any one of the area ID and the adjacent area ID at the time of acquisition, the CPU determines "yes" in step 925, enters step 995 to temporarily end this routine, and enters Figure 6 Step 635 is shown.

[0136] On the other hand, when the current area ID is different from both the area ID and the adjacent area ID at the time of acquisition (i.e., the vehicle VA has entered an area different from the current area and the adjacent area at the time of acquisition), the CPU determines "No" in step 925 and proceeds to step 920 to erase the second map data stored in the temporary storage unit 362. Thereafter, the CPU proceeds to step 995 to temporarily terminate this routine and proceed to step 997. Figure 6 Step 635 is shown.

[0137] <Vehicle control routine>

[0138] The CPU executes the Fig.10 The vehicle control routine shown by the flow chart in FIG.

[0139] Therefore, when the predetermined timing is reached, the CPU Fig.10 The process starts at step 1000 and executes steps 1005 and 1007.

[0140] Step 1005 : The CPU determines the current position of the vehicle VA based on the GNSS signal received by the GNSS receiver 34 .

[0141] Step 1007: The CPU determines whether the map data of the current area corresponding to the current position has been read into the RAM.

[0142] When the map data of the current area has not been read into the RAM, the CPU makes a “No” determination in step 1007 , and executes steps 1009 to 1020 .

[0143] Step 1009 : The CPU reads the map data of the current area into the RAM of the control ECU 30 .

[0144] Step 1010: The CPU determines the positions of the right and left white lines dividing the lane in which the vehicle VA is traveling based on the map data of the current area and the current position of the vehicle VA.

[0145] Step 1015: The CPU obtains a target steering angle θtgt for causing the vehicle VA to pass through a predetermined position between the right white line and the left white line.

[0146] Step 1020 : The CPU sends a steering command signal including the target steering angle θtgt to the steering ECU 60 .

[0147] After that, the CPU enters step 1095 to temporarily end this routine.

[0148] On the other hand, when the CPU enters step 1007 , if the map data of the current area is read into the RAM, the CPU makes a “Yes” determination in step 1007 , executes steps 1010 to 1020 , and enters step 1095 to temporarily terminate this routine.

[0149] According to the present embodiment, the map data of the area where the travel frequency N is greater than the second threshold value N2th is stored in the map data storage unit 360, and the map data of the area where the travel frequency N is less than the second threshold value N2th is stored in the temporary storage unit 362. When the erasure condition is satisfied, the map data stored in the temporary storage unit 362 is erased. Thus, only the map data of the area where the travel frequency N is greater than the second threshold value N2th continues to be stored in the storage device 36, so that the usage capacity of the map data of the storage device 36 can be reduced, and the communication volume between the distribution server 20 and the vehicle VA can also be reduced.

[0150] In the above embodiment, the value obtained by dividing the number of times the area is passed SN by the number of times the area is driven D is used as the travel frequency N, but the number of times the area is passed SN itself may be used as the travel frequency N. The above-mentioned division value as the travel frequency N and the number of times the area is passed are sometimes referred to as "frequency index values".

[0151] The present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

[0152] (First Modification)

[0153] In this modification, the control ECU 30 obtains the driving frequency N' of each driver by dividing the number of times each driver of the vehicle VA passes through the area SN' by the number of times each driver drives D'. The CPU of the control ECU 30 of this modification executes the Fig.11 The map data management routine shown is used instead Figure 6 The map data management routine shown in FIG. Fig.11 In the process of Figure 6 In the same processing steps as shown in the steps, the Figure 6 The same reference numerals as used in the drawings are used and their descriptions are omitted.

[0154] When the specified timing is reached, the CPU Fig.11 The process starts at step 1100 as shown, and steps 1105 and 1110 are executed in sequence.

[0155] Step 1105 : The CPU acquires a driver's seat image from the driver's seat camera device 32 .

[0156] Step 1110: The CPU determines the driver currently sitting in the driver's seat of the vehicle VA (hereinafter referred to as "current driver") by comparing the facial image extracted from the driver's seat image with the facial images of pre-registered drivers.

[0157] After that, the CPU Fig.11 In step 605 shown in FIG. Fig.11 In step 610 shown in FIG. 1 , the current region ID is determined and the current region ID is entered. Fig.11 Step 615 is shown.

[0158] If the current region ID is different from the previous region ID, the CPU Fig.11 In step 615 shown in the figure, it is judged as "No", and the process goes to step 1115. In step 1115, the CPU obtains the driving frequency N' of the current driver in the current area. To describe more specifically, first, the CPU adds "1" to the "number of passes SN' of the current driver in the current area" stored in the EEPROM at the current time point to update the number of passes SN' of the current driver, and divides the updated number of passes SN' by the number of drives D' of the current driver, thereby calculating the driving frequency N' of the current driver in the current area (N'=SN' / D'). It should be noted that in the initialization routine, the CPU determines the current driver, adds "1" to the number of drives D' of the current driver, and stores the added value in the EEPROM. Moreover, the CPU stores the updated driving frequency N' in the EEPROM.

[0159] Then, the CPU executes in step 1120 Fig.12 The map data acquisition subroutine shown in the figure is executed in sequence Fig.11 "Step 630 and Step 635" as shown, and enter step 1195 to temporarily end this routine.

[0160] When entering step 1120, the CPU Fig.12 The process begins at step 1200. Fig.12 In the process of Figure 7 In the same processing steps as shown in the steps, the Figure 7 The same reference numerals as used in the drawings are used and their descriptions are omitted.

[0161] When Fig.12 If the determination result in step 705 is "NO", the CPU proceeds to step 1205 to determine whether the current number of times D' of driving of the driver is greater than a threshold value D'th. Ideally, the threshold value D'th is set to a value smaller than the threshold value Dth.

[0162] If the current driver's driving frequency D' is greater than the threshold D'th, the CPU determines "yes" in step 1205 and proceeds to step 1210 to determine whether the current driver's driving frequency N' in the current area is greater than the first threshold N1th. If the current driver's driving frequency N' in the current area is greater than the first threshold N1th, the CPU determines "yes" in step 1210 and executes Fig.12 Step 735 as shown, and proceed to step 1215.

[0163] In step 1215, the CPU determines whether the current driver's current area travel frequency N' is less than the second threshold value N2th. If the current driver's current area travel frequency N' is less than the second threshold value N2th, the CPU determines "yes" in step 1215 and executes Fig.12 Then, the routine is temporarily terminated by entering step 1295 and the routine is entered. Fig.11 On the other hand, if the current driver's current area travel frequency N' is greater than the second threshold value N2th, the CPU determines "No" in step 1215 and executes Fig.11 Then, the routine is temporarily terminated by entering step 1295 and the routine is entered. Fig.11 Step 635 is shown.

[0164] If the current number of times the driver drives D' is less than the threshold value D'th, the CPU determines "No" in step 1205 and executes Fig.12 When the current driver's driving frequency N' in the current area is less than the first threshold value N1th, the CPU determines "No" in step 1210 and executes Fig.12 The CPU is in the step 715 and step 725 shown in FIG. Fig.12 If the determination in step 705 shown is “yes”, the process proceeds to step 1215 .

[0165] In this modification, the current area travel frequency N' acquired by each driver is compared with the second threshold value N2th, so it is possible to determine whether to store or erase the map data according to the current area travel frequency N' of each driver.

[0166] The travel frequency N' is compared with the first threshold value N1th, and therefore one of the first acquisition request and the second acquisition request is sent according to the travel frequency N'. Thus, the amount of map data to be acquired from the distribution server 20 can be determined according to the travel frequency N' of each driver.

[0167] It should be noted that the first threshold value N1th and the second threshold value N2th used in this modification may be set to values ​​different from the first threshold value N1th and the second threshold value N2th used in the above embodiment, respectively.

[0168] The CPU identifies the current driver based on the driver's seat image, but the present invention is not limited thereto. For example, the CPU may identify the current driver using any one of the driver's smartphone, electronic key, and fingerprint.

[0169] In this modification, the number of times each driver passes through the area SN' can be used as the driving frequency N' of each driver in the area. In this case, the first threshold N1th and the second threshold N2th are set to be larger as the number of times the driver drives D' is larger.

[0170] (Second Modification)

[0171] In this modified example, the control ECU 30 obtains the travel frequency N' of the current area of ​​each driver and the travel frequency N of the current area of ​​the vehicle VA. If the travel frequency N' is greater than the first threshold value N1th, the control ECU 30 sends a first acquisition request, and if the travel frequency N' is less than the first threshold value N1th, the control ECU 30 sends a second acquisition request. Furthermore, if the travel frequency N of the current area of ​​the vehicle VA regardless of the driver is greater than the second threshold value N2th, the control ECU 30 stores the map data sent from the distribution server 20 in the map data storage unit 360, and if the above-mentioned travel frequency N is less than the second threshold value N2th, the control ECU 30 stores the map data in the temporary storage unit 362.

[0172] The CPU of this modification executes Fig.11 The map data management routine shown in FIG. 11 is shown in FIG. 11. The CPU obtains the travel frequency N′ and the travel frequency N in step 1115. Then, after entering Fig.11 In the case of step 1120 shown in FIG. Fig.13 The map data acquisition routine shown in FIG. Fig.13 In the process of Figure 7 and Fig.12 In the same processing steps as shown in the steps, the Figure 7 and Fig.12 The same reference numerals as used in the drawings are used and their descriptions are omitted.

[0173] Therefore, when entering Fig.11 At step 1120 shown, the CPU Fig.13 The process begins at step 1300. Fig.13When the determination in step 705 is "NO", the CPU proceeds to step 1305. In step 1305, the CPU determines whether the driving number D' of the current driver is greater than a threshold D'th and whether the driving number D of the vehicle VA regardless of the driver is greater than a threshold Dth.

[0174] When the driving number D' is greater than the threshold value D'th and the driving number D is greater than the threshold value Dth, the CPU determines "yes" in step 1305 and enters Fig.13 Step 1210 is shown. Fig.13 If the result of the determination in step 1210 is "yes", the CPU executes Fig.13 Step 735 is shown and the process proceeds to step 1310 .

[0175] In step 1310, the CPU determines whether the driving frequency N of the current area of ​​the vehicle VA regardless of the driver is less than the second threshold value N2th. If the driving frequency N is less than the second threshold value N2th, the CPU determines "yes" in step 1310 and executes Fig.13 Then, the CPU enters step 1395 to temporarily terminate this routine and enters step 1396. Fig.11 In contrast, if the driving frequency N is greater than the second threshold value N2th, the CPU determines "No" in step 1310 and executes Fig.13 Then, the CPU enters step 1395 to temporarily terminate this routine and enters step 1396. Fig.11 Step 635 is shown.

[0176] On the other hand, when the CPU enters step 1305, if the number of driving times D' is less than the threshold value D'th or the number of driving times D is less than the threshold value Dth, the CPU determines "No" in step 1305. Fig.13 If the judgment in step 1210 is "No", the CPU executes Fig.13 After that, the CPU enters step 1395 to temporarily terminate this routine and enters Fig.11 Step 635 is shown.

[0177] In the present modification, the travel frequency N of the current area is compared with the second threshold value N2th. Therefore, it is possible to determine whether to store or erase the map data based on the travel frequency N of the vehicle VA regardless of the driver.

[0178] Furthermore, the driving frequency N' of each driver is compared with the first threshold value N1th, and therefore, one of the first acquisition request and the second acquisition request is sent according to the driving frequency N'. Thus, the amount of map data to be acquired from the distribution server 20 can be determined according to the driving frequency N' of each driver.

[0179] (Third Modification)

[0180] The distribution server 20 may manage the travel frequency N of each area of ​​the vehicle VA and transmit the map data to the vehicle VA in accordance with an instruction to delete the map data or store the map data in the map data storage unit 360 according to the travel frequency N of the vehicle VA.

[0181] More specifically, the vehicle VA sends the "vehicle ID as an identifier of the vehicle VA" and the location information including the current location to the distribution server 20 every predetermined time. It should be noted that, when the map data of the current location is not stored in the storage device 36, the vehicle VA sends the above-mentioned location information including the acquisition request.

[0182] When the location information is acquired, the distribution server 20 determines the current area ID corresponding to the current location as the current area ID. If the current area ID is different from the previous area ID, the travel frequency N of the current area is updated. Furthermore, when the location information includes an acquisition request, if the travel frequency N of the current area of ​​the vehicle VA that sent the location information is less than the first threshold value N1th, the distribution server 20 sends the map data of the current area and the adjacent area. It should be noted that the map data includes information that does not allow storage.

[0183] On the other hand, when the driving frequency N in the current area of ​​the vehicle VA that has sent the above-mentioned location information is greater than the first threshold value N1th, if the driving frequency N is greater than the second threshold value N2th, the distribution server 20 will allow the storage information to be included in the map data for sending; if the driving frequency N is below the second threshold value N2th, the distribution server 20 will not allow the storage information to be included in the map data for sending.

[0184] When receiving map data including storage-disallowed information, the vehicle VA stores the map data in the temporary storage unit 362. When a predetermined erasure threshold time has elapsed from the time point (storage time point) when the map data was stored in the temporary storage unit 362, the vehicle VA determines that the erasure condition is satisfied and erases the map data from the temporary storage unit 362. On the other hand, when receiving map data including storage-allowed information, the vehicle VA stores the map data in the map data storage unit 360.

[0185] This modification can also be applied to the first modification and the second modification. In this case, the vehicle VA also includes the driver ID, which is the identifier of the driver currently driving the vehicle VA, in the location information to send the location information. Thus, the distribution server 20 can manage the driving frequency N of each area for each driver.

[0186] (Fourth Modification)

[0187] The erasing condition is not limited to the above-mentioned example, and may be any of the conditions listed below.

[0188] The condition that the erasure threshold time has elapsed since the map data was stored in the temporary storage unit 362

[0189] The condition that a predetermined time has passed since the vehicle VA entered an area different from the area when any acquisition request was sent

[0190] The above-mentioned ignition key switch is changed from the on position to the off position.

[0191] The condition that the capacity of the map data stored in the temporary storage unit 362 is equal to or larger than the threshold value

[0192] ·Vehicle control is interrupted by the driver's operation.

[0193] (Fifth Modification)

[0194] In the above embodiment, the map data to be erased is stored in the temporary storage unit 362 of the storage device 36 , but may be stored in the RAM of the control ECU 30 .

[0195] (Sixth Modification)

[0196] The CPU may execute control for displaying map data of a current area on a display (not shown) as vehicle control.

[0197] In the above-mentioned embodiment, the current position of the vehicle VA is determined based on the GNSS signal, but is not limited thereto. For example, the CPU may also determine the current position of the vehicle VA based on the speed (vehicle speed) Vs of the vehicle VA and the steering angle θ. It should be noted that the vehicle speed Vs is determined based on the detection signal of the wheel speed sensor (not shown) of the vehicle VA that can detect the rotation speed of the wheel.

[0198] The vehicle VA may also be an engine car driven by an engine, an electric car, and a hybrid car.

Claims

1. A map data utilization system, comprising: a map data distribution server configured to be able to transmit map data for each of a plurality of areas each having a prescribed size; as well as A vehicle is equipped with a storage device, a position acquisition device, and a control device, wherein the storage device stores map data sent from the map data distribution server via a network, the position acquisition device acquires a current position, and the control device performs a predetermined vehicle control using the map data stored in the storage device. Wherein, the map data distribution server is configured as: When receiving a map data acquisition request transmitted from the vehicle, map data of an area corresponding to the received map data acquisition request is transmitted to the vehicle, The control device is configured to: sending, as the acquisition request, a request for acquiring map data of an acquisition area including at least the area to which the current position of the vehicle belongs to, to the map data distribution server when map data of the area to which the current position of the vehicle belongs among the plurality of areas acquired by the position acquisition device is not stored in the storage device; receiving the map data of the acquisition area sent from the map data distribution server according to the acquisition request and storing the map data in the storage device; When a frequency index value indicating the frequency of the vehicle traveling in the area to which the position of the vehicle at the time when the acquisition request is sent is equal to or less than a predetermined erasure threshold, erasing the map data of the acquisition area from the storage device when a predetermined erasure condition is satisfied; and When the frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is greater than the erasure threshold, the map data of the acquisition area is maintained and is not erased from the storage device regardless of whether the erasure condition is satisfied.

2. The map data utilization system according to claim 1, wherein: The control device is configured to: When the frequency index value of the area to which the current position of the vehicle belongs is greater than a prescribed acquisition threshold, sending a first acquisition request as the acquisition request to the map data distribution server, wherein the first acquisition request is a request for acquiring map data of the area to which the current position of the vehicle belongs; and When the frequency index value of the area to which the current position of the vehicle belongs is below the acquisition threshold, a second acquisition request is sent as the acquisition request to the map data distribution server, wherein the second acquisition request is a request for acquiring map data of the area to which the current position of the vehicle belongs and an area adjacent to the area to which the current position of the vehicle belongs.

3. The map data utilization system according to claim 2, wherein: The control device is configured to: When the frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is equal to or less than the predetermined erasure threshold, When the area to which the current position of the vehicle belongs becomes different from the area to which the position of the vehicle belonged when the first acquisition request was sent, it is determined that the erasure condition is satisfied, and the map data sent from the map data distribution server according to the first acquisition request is erased from the storage device, When the area to which the current position of the vehicle belongs becomes neither the area to which the position of the vehicle belonged when the second acquisition request was sent nor the area adjacent to the area to which the position of the vehicle belonged when the second acquisition request was sent, it is determined that the erasure condition is met, and the map data sent from the map data distribution server according to the second acquisition request is erased from the storage device.

4. The map data utilization system according to any one of claims 1 to 3, wherein: The frequency index value is obtained by obtaining either a ratio of a passing number to a driving number or the passing number, wherein the passing number is the number of times the vehicle passes through the area within a specified period, and the driving number is the number of times the vehicle is driven within the specified period.

5. The map data utilization system according to any one of claims 1 to 3, wherein: The frequency index value is obtained by obtaining either a ratio of a passing number to a driving number or the passing number, wherein the passing number is the number of times the vehicle driven by a current driver who is the driver of the vehicle at a current time point passes through the area within a specified period, and the driving number is the number of times the vehicle is driven by the current driver within the specified period.

6. The map data utilizing system according to claim 1, wherein: obtaining a ratio of a number of passes to a number of drives as a first frequency index value, wherein the number of passes is the number of times the vehicle driven by a current driver who is the driver of the vehicle at a current time point passes through the area within a prescribed period, and the number of drives is the number of times the vehicle driven by the current driver is driven within the prescribed period, The ratio of the number of passes to the number of drives is obtained as a second frequency index value, wherein the number of passes is the number of times the vehicle passes through the area without distinguishing the driver of the vehicle within the specified period, and the number of drives is the number of times the vehicle is driven without distinguishing the driver within the specified period, The control device is configured to: When the first frequency index value of the area to which the current position of the vehicle belongs is greater than a prescribed acquisition threshold, sending a first acquisition request as the acquisition request to the map data distribution server, wherein the first acquisition request is a request for acquiring map data of the area to which the current position of the vehicle belongs; When the first frequency index value of the area to which the current position of the vehicle belongs is less than the acquisition threshold, sending a second acquisition request as the acquisition request to the map data distribution server, wherein the second acquisition request is a request for acquiring map data of the area to which the current position of the vehicle belongs and an area adjacent to the area to which the current position of the vehicle belongs; When the second frequency index value of the area to which the position of the vehicle belongs when the acquisition request is sent is equal to or less than the erasure threshold, erasing the map data of the acquisition area from the storage device when the erasure condition is satisfied; and When the second frequency index value of the area to which the position of the vehicle belongs when the acquisition request is transmitted is greater than the erasure threshold, storage of the map data of the acquisition area is maintained.

7. A map data utilization method, wherein map data transmitted from a map data distribution server to a vehicle via a network is stored in a storage device provided in the vehicle, and the map data stored in the storage device is used to perform a predetermined vehicle control, wherein: The map data distribution server stores map data for each of a plurality of areas each having a predetermined size. The map data utilization method comprises: The first step is to send a request for acquiring map data of an acquisition area including at least the area to which the current position of the vehicle belongs to, to the map data distribution server, if the map data of the area to which the current position of the vehicle belongs is not stored in the storage device; The second step is to receive the map data of the acquisition area sent from the map data distribution server according to the request and store the map data in the storage device; A third step of erasing the map data of the acquisition area from the storage device when a predetermined erasure condition is satisfied, when a frequency index value indicating the frequency of the vehicle traveling in the area to which the position of the vehicle when the request is sent belongs is equal to or less than a predetermined erasure threshold value; and In the fourth step, when the frequency index value of the area to which the position of the vehicle belongs when the request is sent is greater than the erasure threshold, the map data of the acquisition area is maintained in storage without being erased from the storage device regardless of whether the erasure condition is satisfied.

8. A computer-readable storage medium storing a program, the program being applied to a vehicle, the vehicle having a storage device for storing map data transmitted from a map data distribution server via a network, and using the map data stored in the storage device to perform predetermined vehicle control, wherein: The map data distribution server stores map data for each of a plurality of areas each having a predetermined size. The procedures include: The first step is to send a request for acquiring map data of an acquisition area including at least the area to which the current position of the vehicle belongs to, to the map data distribution server, if the map data of the area to which the current position of the vehicle belongs is not stored in the storage device; The second step is to receive the map data of the acquisition area sent from the map data distribution server according to the request and store the map data in the storage device; A third step of erasing the map data of the acquisition area from the storage device when a predetermined erasure condition is satisfied, when a frequency index value indicating the frequency of the vehicle traveling in the area to which the position of the vehicle when the request is sent belongs is equal to or less than a predetermined erasure threshold value; and In the fourth step, when the frequency index value of the area to which the position of the vehicle belongs when the request is sent is greater than the erasure threshold, the map data of the acquisition area is maintained in storage without being erased from the storage device regardless of whether the erasure condition is satisfied.

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