JP2013242198A - Route search device and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a recommended route to a destination via appropriate transit points by the shortest processing time.SOLUTION: A route search device 1 searches for a recommended route for a vehicle 2 to travel from a departure place to a destination by using link costs of road links. The device 1 comprises: a first search unit 11 which searches for one or a plurality of transit points within a set range from the departure, and section routes to the transit points; a second search unit 12 which repeatedly performs section route search processing for searching for one or a plurality of other transit points within a set range from the obtained one or the plurality of transit points, and section routes to the other transit points, until the vehicle arrives at the destination; and a determination unit 13 which determines the recommended route on the basis of a processing result by the second search unit 12.

Description

  The present invention relates to a route search device and a computer program for searching for a route to a destination.

A technique for causing a computer to search for a route to a destination when the vehicle travels toward the destination is already known (see Patent Document 1). For example, when a driver who drives a car inputs a destination to an in-vehicle device, information on the destination and a departure location (current location) is transmitted to the server device by communication, and the server device stores roads stored in the database. Using the link cost of the link, a process for searching for a route from the departure place to the destination is executed by a predetermined search algorithm. When the recommended route is determined, information on the recommended route is transmitted to the in-vehicle device, and the in-vehicle device that has received this information notifies the driver of the recommended route and can start route guidance along the recommended route. It becomes possible.
Furthermore, in such a route search system, it is possible to search not only the destination but also the route that reaches the destination after passing through this route by setting the waypoint by the driver. It has become.

Here, in recent years, electric vehicles have been developed, but at present, the cruising distance is short (less than 200 km). Therefore, even if the electric vehicle is a day drive, it may be necessary to stop at the charging station and charge the battery on the way.
In this case, it is conceivable that the driver sets the charging station as the transit location using the system that searches for the route that reaches the destination after passing through the transit location as described above. However, it is difficult to determine which charging station should be set as a transit point.

  Therefore, after searching for the route from the departure point to the destination in the same way as when no waypoint is set, the charging station existing along the route is extracted from the map database, and the route to stop at this charging station is selected. It may be determined as the final recommended route. More specifically, as shown in FIG. 9, a route traveling on a highway is searched as a route that reaches the destination from the departure point to the destination, for example, at the shortest distance, and the charging station E1 is obtained from the interchange IC 3 of this highway. The route A1 that returns to the interchange IC3 and travels on the highway again is determined as the final recommended route.

JP 2011-60019 A

  However, in this case, the route A1 is not a route that reaches the destination at the shortest distance. In particular, as shown in FIG. 9, when heading to a destination through a region where the number of charging stations is small and the interchange IC3 on the highway and the charging station E1 are separated from each other, not the highway but the charging station E1 is routed. The route A2 traveling on the general road included in the middle of the road may be the shortest.

Also, if the mileage to the destination is very long compared to the electric vehicle's cruising range and you have to stop at the charging station multiple times, as another route search process, Routes that minimize the sum of link costs by first extracting each existing charging station as a transit point (candidate) and calculating the link cost using all combinations of routes between these charging stations Can be considered as a recommended route.
However, when heading to the destination through an area (urban area) where there are relatively many charging stations, the amount of calculation required is enormous and the processing time is long, and the user's request is quickly met. Therefore, there is a problem that the recommended route cannot be provided.

There are not only electric vehicles but also vehicles that are driven by an internal combustion engine in such a way to the destination via the waypoint, so that there are extremely few gas stations to the destination. On the other hand, if it is necessary to stop at the gas station and refuel, it is considered that the same problem as in the case of the electric vehicle may occur.
Furthermore, the purpose of stopping at the transit point is other than charging the battery or refueling. For example, when drivers continue to drive for a long time, fatigue accumulates, so they may stop at service facilities, roadside stations, and other resting facilities. It is also necessary to search for a recommended route to reach the destination while taking it.

  Therefore, an object of the present invention is to determine a recommended route to a destination via an appropriate waypoint in as short a processing time as possible.

  (1) The present invention is a route search device that searches for a recommended route that a vehicle should travel from a departure point to a destination by using a link cost of a road link, and is within a set range starting from the departure point. A first search unit that obtains one or a plurality of waypoints and a section route to the waypoint, one or more other waypoints within the set range starting from the obtained one or more waypoints, and the other A second search unit that repeatedly performs a section route search process for obtaining a section route to the waypoint of the vehicle until the destination is reached, and a determination unit that determines the recommended route based on a processing result of the second search unit; It is characterized by having.

  According to the present invention, one or a plurality of waypoints within a set range starting from the departure point are obtained. Furthermore, the section route search process for obtaining one or a plurality of other waypoints within the set range starting from the waypoint is repeated until the destination is reached. For this reason, all routes from the departure point to the destination are automatically searched while obtaining the waypoints. In addition, it is possible to search all routes with a small number of times of transiting via points, and further, it is not necessary to calculate the total number of route combinations between points that can be transit points, thereby shortening the processing time. .

  When the vehicle is an electric vehicle that uses battery power as travel power, the set range can also be referred to as a cruising range, and this range can be based on the travelable distance based on the remaining power amount of the battery. In the case of a vehicle that uses the power of the internal combustion engine as travel power, the set range (a cruising range) can be based on a travelable distance based on the remaining amount of fuel. And, when considering a stopover as a resting place, the driver gradually accumulates fatigue due to driving of the vehicle. Therefore, the range where the fatigue does not exceed the peak, for example, the range where the vehicle continuously travels for 2 hours is It becomes a range.

(2) Moreover, it is preferable that the said 1st search part and the said 2nd search part require | calculate the said area | region path | route using the dynamic information which changes with time.
For example, there is traffic information indicating traffic congestion on the road as dynamic information, the vehicle is an electric vehicle, the waypoint is a charging station, and according to the traffic information, in the time zone on the way to the charging station If a traffic jam is expected and the arrival time of the charging station is outside business hours due to this traffic jam, the charging station is not set as a transit point.

(3) Further, in the case of (2), the second search unit includes the time spent at the obtained waypoint in the link cost, and traffic information after the passage of time spent at the waypoint, It is preferable to obtain the section route using the dynamic information that changes over time.
In this case, the route search result can be made more accurate.

(4) In addition, when a plurality of waypoints are obtained by the first search unit, since the second search unit obtains a section route from each of these waypoints to each other waypoint as a starting point, There is a possibility that the search for the section route becomes redundant.
Therefore, in this case, the second search unit recommends the section route having the minimum link cost when there are a plurality of section routes from a plurality of waypoints as a starting point to one other waypoint. It is preferable to leave as a section route candidate to be included in the route.
In this case, the section route whose link cost is not minimized is deleted from the candidates, and the section route that becomes superior when the link costs are compared is left as a candidate, so the range in which the search for the section route becomes redundant is reduced.

(5) Moreover, it is preferable that the said vehicle is an electric vehicle which has a battery which can be charged, and uses the electric power of this battery as driving power, and the said stop includes the charging station which charges the said battery.
In this case, a recommended route that allows the electric vehicle to reach the destination through the charging station is obtained.

(6) In the above (5), it is preferable that the setting range is based on a remaining power amount of the battery.
In this case, it is possible to prevent a search for a path that runs out of the battery by obtaining a charging station that passes through based on the remaining electric energy of the battery.

(7) Further, the route search device according to (5) or (6) described above is the location of the charging station, the time required for staying at the charging station, the presence or absence of a quick charging function at the charging station, and the use of the charging station. A database for storing attribute information of the charging station indicating at least one of the possible time zones is further provided, and the first search unit and the second search unit search for a section route based on the attribute information. Is preferred.
In this case, a more appropriate section route can be searched. For example, if a section route is searched based on information indicating the required stay time at the charging station or information indicating the presence or absence of the quick charging function, the stay time spent at the charging station can be more accurately reflected in the link cost. Can do. In addition, by searching the section route based on information indicating the available time zone of the charging station, if the arrival time at the charging station is outside the available time zone, the charging station is used as a transit point. It is possible to prevent setting.

(8) Moreover, it is preferable that the route search device according to (7) further includes an information input unit for adding and storing the attribute information in the database.
For example, for public charging stations, it is relatively easy to collect the attribute information and create a database, but for private charging stations other than the public charging station, enter the attribute information into the information input. It becomes possible to add to the database by the department, and it is also possible to make the attribute information of the private charging station into a database.

(9) Further, in the route search device according to any one of (5) to (8), the second search unit determines a predetermined charge amount from a remaining power amount of the battery when it arrives at the charging station. It is preferable to obtain the charging time required to reach, and include the charging time in the link cost to obtain the section route.
In this case, for example, when the battery arrives at the charging station and the remaining battery level is 40%, the charging time required to reach a predetermined charging amount (for example, 80%) is obtained, and this charging time is included in the link cost. Then, the section route is obtained based on the link cost including the charging time. As a result, for example, the arrival time at the destination can be estimated more accurately.

(10) Further, the present invention is a computer program for causing a computer to execute a process of searching for a recommended route for a vehicle to travel from a departure point to a destination using a link cost of a road link, Obtaining one or more waypoints within the set range starting from the departure point and a section route to the route point, and one or more within the set range starting from the obtained one or more waypoints Based on the result of the step of repeatedly obtaining a section route search process for obtaining another route point and a section route to the other route point until reaching the destination, and the result of the step of repeatedly performing the section route search process Determining the recommended route.
According to the present invention, the same operational effects as the route search device described in (1) can be obtained.

  According to the present invention, all the routes from the departure point to the destination are automatically searched while obtaining the waypoints, and all the routes that are less frequently routed are searched, and further, the points that can be route points It is no longer necessary to calculate the total route combination between them, and the processing time can be shortened.

It is a block diagram which shows an example of the traffic information system provided with the route search apparatus of this invention. It is a flowchart explaining a route search method. It is explanatory drawing explaining the process of a route search in order. It is explanatory drawing explaining the process of a route search in order. It is explanatory drawing explaining the process of a route search in order. It is explanatory drawing explaining the process of a route search in order. It is explanatory drawing which shows the image of the search range from each charging station. It is explanatory drawing which shows the image of the search range from each charging station. It is explanatory drawing of the conventional route search.

Embodiments of the present invention will be described below.
[Traffic information system]
FIG. 1 is a block diagram showing an example of a traffic information system provided with a route search device of the present invention. The traffic information system includes a vehicle 2, a vehicle-mounted device 3 mounted on the vehicle 2, a road-side communication device 4 that communicates wirelessly with the vehicle-mounted device 3, and can communicate with the road-side communication device 4 to collect various types of information and A server device 5 for generating information is included.
In addition, the vehicle-mounted device 3 can be a mobile terminal such as a smartphone carried by a driver (passenger) other than a device fixed to the vehicle 2. When the in-vehicle device 3 is a mobile terminal, the roadside communication device 4 is a base station device that performs wireless communication with the mobile terminal.

The vehicle 2 according to the present embodiment has a rechargeable battery 7 and is an electric vehicle that uses the power of the battery 7 as travel power.
The in-vehicle device 3 includes an in-vehicle computer, acquires probe information (also referred to as floating car information) of the vehicle 2 in which the in-vehicle device 3 is mounted, and transmits the probe information to the server device 5 through the roadside communication device 4. Furthermore, information generated by the server device 5 (information on recommended routes to be described later) is transmitted to the in-vehicle device 3 through the roadside communication device 4.

The in-vehicle device 3 includes an input unit 3a that receives an operation of a driver (passenger) and inputs various information, and a position acquisition unit 3b that can acquire information on the current position.
The input unit 3a is composed of, for example, a touch panel operated by a driver, and a destination is input by character input or the like. The input destination is used as destination information, is included in the transmission information i1 together with the identification information (vehicle ID) of the vehicle 2, and is transmitted to the server device 5. The transmission information i1 is a recommended route search request signal for the server device 5.
The position acquisition unit 3b is composed of a device having a GPS function, for example, and acquires information on the current position. The acquired current position information is included in the transmission information i1 and transmitted to the server device 5.
Moreover, the vehicle-mounted apparatus 3 can acquire the information of the remaining electric energy in the battery 7 of the own vehicle, and this information is also included in the transmission information i1.

  A large number of roadside communication devices 4 are installed on roads in each region. Each roadside communication device 4 includes a communication device and a communication controller, can wirelessly communicate with the in-vehicle device 3, and can communicate with the server device 5 by wire (or wirelessly).

  The server device 5 includes a server computer, a storage device 15 including a hard disk storing a computer program and various information, a communication device 16 including a communication interface for communicating with the roadside communication device 4, and arithmetic processing. And an arithmetic unit 17 having a function of performing the above. Further, the server device 5 includes an information input unit (interface) 18 for adding information to a later-described database stored in the storage device 15 for storage.

  The storage device 15 exists in each area, a road network database 15a storing map information of road maps in each area, a traffic information database 15b storing link cost information for each road link, and each area. It has a charging station database 15c that stores charging stations (included in the road map) and their attribute information. In the present embodiment, the link cost of the traffic information database 15b is travel time, and the information on the power consumption of the battery 7 of the electric vehicle 2 required to travel each road link is stored in the database 15b. It is set for each road link.

  The map information includes, for example, road link information formed by a combination of nodes and road links, where a road map is divided into meshes. In addition, the map information includes information on charging stations (charging facilities) for charging batteries of electric vehicles installed in each region. It is associated with attribute information described later in the database 15c.

  The link cost information in the traffic information database 15b is associated with the road link set in the map information. Further, the link cost for each road link is also divided for each time zone, and the travel time for each time zone is reflected. This travel time is generated based on statistical values such as past performance values. Since this travel time is affected by the traffic congestion of the road link, this travel time information can be used as traffic jam information. The traffic jam information may be traffic information other than the travel time. In this manner, the storage device 15 stores dynamic information that changes with time, such as travel time for each time zone. The traffic information database 15b also stores information about the length and gradient for each road link.

  The charging station database 15c includes attribute information indicating the location of the charging station, the time required for staying at the charging station, the presence / absence of a quick charging function at the charging station, and the usable time zone (business hours) of the charging station. Accumulated for each charging station. The location of the charging station is associated with the road link set in the map information. The time required for staying at the charging station includes time required for charging, set-up time for charging work, and work time after the end of charging, such as a time for paying a fee.

[Route search device]
The server device 5 has a plurality of functional units having various functions, and one of these functional units is the route search device 1. In other words, the arithmetic device 17 included in the server device 5 includes a computer having a CPU and an internal memory, and a computer program for causing the server device 5 to function as the route search device 1 is installed in the storage device 15. Each function (the 1st search part 11, the 2nd search part 12, and the determination part 13) with which this route search apparatus 1 is provided is exhibited when the said computer program is run by the arithmetic unit 17. FIG. Each of these functions will be described later.

As described above, when the transmission information i1 is transmitted from the in-vehicle device 3 and is received by the route search device 1, the route search device 1 recommends that the vehicle 2 travel from the departure point to the destination via the waypoint. A process for searching for a route using the link cost of the road link is started. Note that the departure place is based on the current position information included in the transmission information i1, and the destination is based on the destination information included in the transmission information i1. As will be described later, the waypoint is included in the recommended route and automatically determined by the route search device 1.
Then, when the recommended route is determined, the route search device 1 includes the recommended route information in the response information i2 and transmits it to the in-vehicle device 3. Upon receiving this response information i2, the in-vehicle device 3 can output a recommended route to the driver, and can perform route guidance along the recommended route.
In the present embodiment, the waypoint is a charging station that charges the battery 7 of the electric vehicle. According to the route search device 1, the electric vehicle can reach the destination by way of the charging station. The recommended route is obtained.

[Each function of the route search device]
Each of the first search unit 11 and the second search unit 12 determines a section route that the vehicle 2 should travel from a certain point (first point) to another point (second point) using the link cost of the road link. It has a function to search by the search algorithm. The link cost of the road link is accumulated in the traffic information database 15b, and the first search unit 11 and the second search unit 12 refer to this database 15b.

  Further, each of the first search unit 11 and the second search unit 12 obtains a charging station serving as a transit point and a section route to the charging station based on a cruising range (setting range). This cruising range is based on the remaining power amount of the battery 7. That is, the cruising range is determined by the amount of remaining power obtained by subtracting the amount of power consumed with traveling from the amount of power of the battery 7 at the starting point (departure point or charging station). That is, for example, the cruising range is until the remaining power amount becomes less than a predetermined value (for example, 20%). As described above, since the power consumption information of the battery 7 of the electric vehicle 2 required for traveling on each road link is set in the database 15b for each road link, the first search unit 11 and the second The search unit 12 can obtain one or a plurality of charging stations within the cruising range and a section route to the charging station by executing a route search process while referring to the database 15b.

  In addition, although various algorithms can be adopted as the search algorithm, the present embodiment is a Dijkstra method, and each of the first search unit 11 and the second search unit 12 has a small sum of link costs of road links. A simulation for searching for a section route (which is the minimum) is performed. In the present embodiment, since the link cost is the travel time, the route search apparatus 1 can determine a recommended route that shortens the travel time as much as possible from the departure point to the destination.

  Then, as will be described in detail later, according to the search unit composed of the first search unit 11 and the second search unit 12, a section route to the charging station is obtained, and based on this section route, the departure place It is possible to search for all routes from the starting point to the destination that can be reached via the waypoint, and the determination unit 13 determines the recommended route based on the processing result of the second search unit 12. In particular, according to the search unit including the first search unit 11 and the second search unit 12 as in the present embodiment, a plurality of all routes may be searched. In this case, the optimum route is selected from all these routes. One whole route is selected by the determination unit 13, and this one whole route is determined as a recommended route.

  Moreover, the 1st search part 11 and the 2nd search part 12 search an area path | route based on the attribute information of a charging station by referring the database 15c for charging stations. For example, if the section route is searched based on the information indicating the stay required time at the charging station or the information indicating the presence or absence of the quick charge function as the attribute information, the stay time spent at the charging station can be more strictly linked cost. Can be reflected. In addition, if the arrival time at the charging station is out of the usable time zone (out of business hours) by searching the section route based on the information indicating the usable time zone of the charging station, the charging is performed. Stations are never set as transit points.

  The information input unit 18 can add and store attribute information of other charging stations in the charging station database 15c. For example, at present, charging stations are often installed in electric vehicle stores. Such a charging station is generally an open charging station and can be said to be a public charging station. For such a public charging station, it is relatively easy for the route search device 1 to collect attribute information (information indicating the presence or absence of the quick charging function and information indicating the usable time zone) and create a database. It is. However, it is necessary to additionally register the attribute information of the charging station (charging facility) installed privately in the database 15c. Therefore, for example, the driver transmits the transmission information i1 including the attribute information of the charging station and the request information for requesting registration from the in-vehicle device 3, and when the route search device 1 receives the request information, the information input unit By 18, the attribute information of such a private charging station is added to the database 15 c.

  In addition, there are facilities in the charging station that have usage restrictions such as a membership system and a pre-registration system. Therefore, information on such usage restrictions is also stored in the charging station database 15c, and the first search unit 11 and the second search unit 12 consider such information as a transit point. Ask for a charging station.

[Route search method]
A route search method executed by the route search apparatus 1 having the above configuration will be described. FIG. 2 is a flowchart for explaining this route search method. 3-6 is explanatory drawing explaining a route search in order. In FIG. 4 to FIG. 6, charging stations that can serve as transit points are designated E1 to E8.

  As described above, the transmission information i1 (see FIG. 1) is transmitted from the in-vehicle device 3, and the route search device 1 receives the transmission information i1. In addition to the ID information of the vehicle 2 included in the transmission information i1, this vehicle 2 information on the current position (starting place), information on the destination, and information on the remaining electric energy of the battery 7 are acquired (step S1 in FIG. 2). Thereby, as shown in FIG. 3, the starting point and the destination are set on the map based on the road network database 15a (see FIG. 1).

  The first search unit 11 refers to each database, and performs processing for obtaining a charging station included in a cruising range starting from the departure point and a section route from the departure point to the charging station based on the Dijkstra method. Perform (step S2). The 1st search part 11 finds the reachable charging station, subtracting the electric energy of the battery 7 consumed every time it follows a road link from the electric energy of the battery 7 in the starting point (starting place). In the present embodiment, as shown in FIG. 4, charging stations E1 to E5 are obtained, and section routes w1 to w5 from the departure point to the charging stations E1 to E5 are obtained. These charging stations E1 to E5 are charging stations (candidates) that pass through first.

Such processing for obtaining a charging station is performed individually in parallel. That is, the calculation for obtaining the charging stations E1 to E5 and the calculation for obtaining the section paths w1 to w5 are executed individually in parallel (progressed simultaneously).
In step S2, a section route is obtained using dynamic information that changes over time. As dynamic information that changes over time, for example, there is traffic information related to traffic congestion on a road. Such traffic information is accumulated in the traffic information database 15b. By referring to the database 15b, the first search unit 11 calculates the link cost of the section route using the dynamic information.

In addition, according to the map information, there are other charging stations E6 to E8 indicated by two-dot chain lines in FIG. 4 in the direction from the departure point to the destination, but these charging stations E6 to E8 are It exists in a position that is not included in the cruising range starting from the departure point. For this reason, the 1st search part 11 cannot obtain | require these charging stations E6-E8 as the first waypoint.
That is, in an electric vehicle, the distance that can be traveled by one cruising is limited, for example, 200 km when the battery 7 is fully charged. Therefore, in the case of an electric vehicle, a range having a radius of 200 km centering on the departure point is the maximum of one cruising range. The cruising range changes according to the gradient of the road link on the way.

  Further, in this step S2, if there are a plurality of section routes from one departure place to one charging station, a section route that minimizes the sum of the link costs of road links is included in the final recommended route. To leave as a candidate for the route. For example, when there are a plurality of section routes that reach the charging station E2 from the departure place, only the section route w2 that minimizes the sum of the link costs is left as a candidate. In this embodiment, the section routes remaining as candidates are w1 to w5, and information on these section routes w1 to w5 and information on the charging stations E1 to E5 that pass through are stored in the storage device 15 ( Step S3).

  The second search unit 12 refers to each database, and based on the Dijkstra method, another charging station included in the cruising range starting from each of the charging stations E1 to E5 obtained by the first search unit 11, and Then, a section route search process (first time) for obtaining a section route from each of these starting points (E1 to E5) to another charging station is performed (step S4). The 2nd search part 12 finds the reachable charging station, subtracting the electric energy of the battery 7 consumed every time it travels a road link from the electric energy of the battery 7 in the starting point (each charging station E1-E5). In this embodiment, as shown in FIG. 5, charging stations E6 to E8 are obtained, and section routes w6 to w14 from the charging stations E1 to E5 to the charging stations E6 to E8 are obtained. The charging station obtained by the section route search process (first time) is a charging station (candidate) that passes through the second time.

The charging stations obtained by the section route search process are charging stations E6 to E8 different from the charging stations E1 to E5 that are the starting points, and are charging stations E6 to E8 that have not been obtained so far.
Moreover, the process for calculating | requiring such a charging station is advanced separately in parallel. That is, the calculation for obtaining the charging stations E6 to E8 and the calculation for obtaining the section paths w6 to w14 are individually executed in parallel (progressed simultaneously).

  Further, in this step S4, a section route is obtained using dynamic information that changes over time. As dynamic information that changes over time, for example, there is traffic information related to traffic congestion on a road. Such traffic information is accumulated in the traffic information database 15b, and by referring to this database 15b, the second search unit 12 calculates the link cost of the section route using the dynamic information.

In addition, as shown in FIG. 5, the destination exists further in the direction from each charging station E1 to E5 toward another charging station E6 to E8. However, this destination exists at a position not included in the cruising range starting from the charging stations E1 to E5. For this reason, the 2nd search part 12 cannot search the section route from each of the charging stations E1-E5 to the destination in the section route search process (first time).
That is, since the destination does not exist and the charging stations E6 to E8 exist in a range within one cruising range starting from each of the charging stations E1 to E5, these charging stations E6 to E8 exist. , And the section routes w6 to w14 are obtained by the second search unit 12.

  Further, in this section route search process (step S4), if there are a plurality of section routes from one charging station to one other charging station, the section route that minimizes the sum of the link costs of road links is selected. And leave as a candidate of the section route included in the final recommended route. For example, when there are a plurality of section routes that reach the charging station E6 from the charging station E3, only the section route w7 that minimizes the sum of the link costs is left as a candidate.

Furthermore, in this section route search process (step S4), if there are a plurality of section routes (candidates) that reach each other charging station from each of the plurality of charging stations as the starting points, The section route that minimizes the sum of the link costs of road links is left as a candidate section route included in the final recommended route. For example, in FIG. 5, as a section route reaching the charging station E7, a section route W8 starting from the charging station E3, a section route W10 starting from the charging station E4, and a section path W13 starting from the charging station E5. Among them, only the section route (W8 in this embodiment) having the minimum link cost is left as a candidate, and the section route W10 and the section route W13 are sections included in the final recommended route. It is not left as a candidate route.
As described above, in step S4, the section routes remaining as candidates are the section routes w7, w8, w9, and w14. Is stored in the storage device 15 (step S5).

In this way, section routes for which the sum of link costs is not minimized are deleted one after another from the candidates, and section routes w7, w8, w9, and w14 that are superior when link costs are compared are left as candidates. The range in which becomes redundant is reduced.
This will be described with reference to the drawings. In the section route search process (first time), a plurality of charging stations included in the cruising range starting from the charging stations E1 to E5 are required. The search ranges from the charging stations E1 to E5 are shown in FIG. As shown in FIG. That is, the search range starting from the charging station E1 is within the range of a circle (ellipse) indicated by the symbol Q1, and similarly, the search range of the charging stations E2 to E5 is the circle indicated by the symbols Q2 to Q5, respectively ( Within the range of an ellipse). The reason why the search range is an ellipse is that, in the present embodiment, a search range determination method that prioritizes the direction of the destination is employed.

And in this section route search process (the first time), when the section route search from each of the charging stations E1 to E5 is individually executed in parallel, as shown in FIG. The search in the area becomes redundant. However, according to the present embodiment, the link cost (sum) of the route starting from one charging station is the link cost (sum) of the route starting from the other charging station on the intermediate line of the overlapping region. ), The other route is deleted and only one route is removed, so that no redundant area is generated. Thus, the image of the search range from each of the charging stations E1 to E5 in the present embodiment in which no redundant area has occurred is as shown in FIG.
Note that the processing time for searching for a section route is proportional to the number of elements (roads / intersections) to be searched, and the number of elements is generally proportional to the total area to be searched (search range). Therefore, in the present embodiment, the overlapping search range is reduced, which greatly contributes to shortening the processing time.

The section route search process will be further described. As shown in FIG. 4, since the section routes w1 to w5 are obtained by the first search unit 11, the power consumption when the electric vehicle travels on the section paths w1 to w5, that is, the charging stations E1 to E5, It is possible to calculate (estimate) the remaining power amount when it arrives. In each of the charging stations E1 to E5, charging is performed according to the power consumption due to traveling on each of the section routes w1 to w5, so that the charging time until a predetermined charging amount (for example, 80% charging) is reached. It can be different.
Therefore, the second search unit 12 obtains a charging time required to reach a predetermined charging amount (for example, 80% charging) from the remaining battery level when arriving at the charging stations E1 to E5, and uses this charging time as a link cost. Including the process for obtaining the section route.

For example, in the electric vehicle that has reached the charging station E3, if the remaining battery level is calculated to be 40%, the charging time required to reach a predetermined charging amount (for example, 80%) is obtained. It is included in the link cost. Further, in the electric vehicle that has reached the charging station E4, when the remaining battery level is calculated to be 60%, the charging time required to reach a predetermined charging amount (for example, 80%) is obtained, and this charging time is calculated. It is included in the link cost. The relationship between the charge amount and the charge time is made into a database, and this database is stored in the storage device 15.
In step S4, as described above, in consideration of the difference in link cost due to the difference in charging time for each charging station, only the section route having the minimum link cost is left as a candidate. In addition, by including the charging time in the link cost as described above, it is finally possible to estimate the arrival time at the destination more accurately.
In addition, the charging time in each charging station is calculated | required based on the electric power (rapid or normal) of a charging station (charging equipment).

  In addition, as described above, the second search unit 12 includes the time spent in the charging stations E1 to E5 in the link cost, and is spent in each of the charging stations E1 to E5 as dynamic information that changes over time. The section route is obtained using the traffic information after the elapse of time. For example, when traveling on the section route w3, charging at the charging station E3, and traveling on the section route w8, the section route w8 is congested at the time of arrival at the charging station E3, and the section route w8 has the lowest link cost. Even in such a case, when the charging time at the charging station E3 elapses (for example, one hour after the arrival time), the congestion of the section route w8 may be resolved. . In this case, the link cost of the section route w8 can be minimized. In addition, since the information indicating the relationship between the road link for each time zone (each time) and traffic information such as traffic jams is databased as described above (database 15b), the second search unit 12 The link cost can be calculated by referring to the database.

Furthermore, at the time when the recommended route search process (step S2) shown in FIG. 2 is started, for example, the charging station E6 (see FIG. 5) is in business hours (chargeable time), but referring to the traffic information database 15b. On the road on the way to the charging station E6, traffic congestion is expected at the scheduled time of travel, and if this traffic congestion causes the arrival time at the charging station E6 to be out of business hours, the charging is performed. It is necessary to prevent the station E6 from being set as a transit point. Therefore, the second search unit 12 uses the dynamic information that changes over time, that is, the traffic information of the scheduled time zone that passes the road link on the way to the charging station E6, to obtain the section route, It is possible to prevent the charging station E6 from being set as a transit point. The business hours of the charging station E6 can be determined by referring to the attribute information related to the usable time zone stored in the charging station database 15c.
In the following embodiment, a case will be described in which E6 is included as a charging station via.

Returning to step S5 of FIG. 2, when the information on the charging stations E6 to E8 and the information on the section routes w7, w8, w9, and w14 are stored in the storage device 15, the second search unit 12 It is determined whether or not the search has reached the destination (step S6).
In this embodiment (FIG. 5), since it has not yet reached (“No” in step S6), the process returns to step S4, and the second search unit 12 executes the section route search process (second time).

  That is, the second search unit 12 refers to each database, and is included in the cruising range starting from each of the charging stations E6 to E8 determined by the section route search process (first time) based on the Dijkstra method. And a section route search process (second time) for obtaining a section route from each of the charging stations and the starting points (E6 to E8) to each of the other charging stations (step S4). Similarly to the first time, in this second time as well, the second search unit 12 calculates the power amount of the battery 7 that is consumed every time the road link is traveled from the power amount of the battery 7 at the starting point (each of the charging stations E6 to E8). While subtracting, it tries to find another charging station within range.

  However, in this embodiment, since it is detected first that the destination is included in the cruising range starting from each of the charging stations E6 to E8, in this section route search process (second time), charging is performed. Instead of the station and its section route, section routes w15 to w17 from the charging stations E6 to E8 to the destination included in the cruising range are obtained (see FIG. 6).

In the search process by the second search unit 12, if there are a plurality of section routes from one charging station to one destination, the section route that minimizes the sum of the link costs of the road links is the final one. It remains as a candidate for a section route included in the recommended route. For example, when there are a plurality of section routes reaching the destination from the charging station E6, only the section route w15 having the minimum sum of link costs is left as a candidate.
In this embodiment, the section routes remaining as candidates are the section routes w15 to w17, and information on these section routes w15 to w17 is stored in the storage device 15 (step S5).

  As described above, the second search unit 12 includes a plurality of different waypoints within the cruising range starting from each of the plurality of charging stations obtained by the first search unit 11 or the second search unit 12, and The section route search process (step S4) for obtaining the section route to each of these other waypoints is repeated until the destination is reached.

Then, if the destination has been reached in the section route search, “Yes” is determined in step S6. Then, the determination part 13 performs the process which determines a recommended route (step S7), includes the information of the determined recommended route in the response information i2, and transmits to the vehicle equipment 3 (step S8).
In the present embodiment, as shown in FIG. 6, the first route G1 passing through the charging stations E3 and E6 and the charging stations E3 and E7 are taken as all routes from the starting point to the destination. The second whole path G2, the third whole path G3 via the charging stations E4 and E6, and the fourth whole path G4 via the charging stations E5 and E8 are acquired, and all these four paths are obtained. G1 to G4 are stored in the storage device 15.

  As described above, since the section route search process (step S4) by the second search unit 12 is performed, all four routes from the departure point to the destination are obtained. Among these four all routes G1 to G4, one optimum all route is determined as the recommended route. This determination is made based on conditions initially set in the route search device 1 or based on conditions set by the driver. When the driver sets conditions, the transmission information i1 includes setting information indicating conditions for the determination unit 13 to determine a recommended route.

The conditions for selecting one optimum recommended route from a plurality of routes include, for example, the time required to arrive at the destination, the distance required to reach the destination, battery power consumption, There is a remaining power amount of the battery 7 when it arrives at the destination.
For example, the third entire route G3 passing through the charging stations E4 and E6 is determined as the recommended route based on the condition that the time required to arrive at the destination is the shortest.

[Regarding the route search apparatus 1 according to the present embodiment]
Moreover, in embodiment described above, the 1st search part 11 and the 2nd search part 12 use the travel time (traffic information) for every time zone as dynamic information which changes with time for the search of a section route. Although the use has been described, the dynamic information may be other than this. For example, there are information on traffic restrictions such as road closures and speed restrictions, information on power at each charging station, and information on factors affecting the power consumption of the battery 7 of the electric vehicle. The information on the factor includes, for example, information on the weather in the area from the starting point to the destination because the wiper is operated by the electric power of the battery 7 during rain. Further, since the headlight is turned on by the power of the battery 7 according to the degree of sunshine or traveling in the tunnel, there is information on lighting / illuminance of the headlight and the like.
Further, as information on factors affecting the power consumption of the battery 7, there is information on weather (temperature). Ambient temperature affects the operating load of on-board air conditioners (air-conditioning equipment), especially in the case of electric vehicles, and is not equipped with heaters that use waste heat like gasoline cars. When the temperature is low, it is necessary to operate the air conditioner for heating. Thus, since the air conditioner is operated regardless of whether the ambient temperature is high or low, power of the battery 7 is largely consumed. Moreover, since the electric power of the battery 7 will also fall if ambient temperature becomes low, it is preferable to include the information about a weather (temperature) as information of the factor which affects the power consumption of the battery 7. FIG.
Such dynamic information is stored in the storage device 15 as a database, and the first search unit 11 and the second search unit 12 refer to this database to determine the battery 7 in each road link and each section route. The power consumption can be dynamically calculated separately from the power consumption of the running itself, and this can be reflected in the search for the section route (the cruising range).

  Moreover, the 1st search part 11 and the 2nd search part 12 may refer static information for the search of a section route. As static information, for example, there is information regarding the gradient (road gradient) of each road link. This road gradient information is important when calculating the power consumption of the battery 7 when traveling on each road link. For example, in the case of a road link with a large upward gradient, the power consumption of the battery 7 increases. Such static information regarding the road gradient is stored in a database in the storage device 15, and the first search unit 11 and the second search unit 12 refer to this database. Thereby, static information can be reflected in the search for the section route (the cruising range).

As described above, according to the route search device 1 according to the present embodiment, as shown in FIG. 6, a plurality of charging stations E <b> 1 to E <b> 5 within the cruising range starting from the departure point are obtained, and the second search unit According to the section route search processing by No. 12, a plurality of other charging stations E6 to E8 within the cruising range starting from the charging stations E1 to E5 are obtained. Since such section route search processing is repeatedly performed until the destination is reached, all routes from the departure point to the destination are automatically searched while obtaining the charging station. In addition, all routes that have the smallest number of times of passing through the charging station are searched, and further, it is not necessary to calculate the total combination of routes between points that can become charging stations, and the processing time can be shortened.
Then, when a plurality of routes from the departure point to the destination are obtained while obtaining a charging station, one of them is determined as a recommended route.
As a result, it is possible to obtain a recommended route that can reach the destination via the charging station even if the cruising distance of the electric vehicle is shorter than the distance from the departure place to the destination.

[In the case of a vehicle using the power of the internal combustion engine as travel power]
In the above embodiment, the case where the vehicle is an electric vehicle and the waypoint is a charging station has been described. However, the vehicle and the waypoint included in the route search target by the route search device 1 of the present invention are other things. There may be. For example, the vehicle may have an internal combustion engine that runs on gasoline, and may be an automobile that uses the power of the internal combustion engine as running power. In this case, the transit point is a gasoline station that replenishes fuel. In this case, the cruising range (setting range) is based on the distance that can be traveled by the fuel remaining in the fuel tank. That is, a route search is performed as fuel consumption instead of the power consumption of the battery 7 in the embodiment.
For example, when there is a destination in a depopulated area, the distance between the gas stations is long between the destination and the vehicle, and the fuel tank is small, a route search similar to the route search according to the above embodiment is performed. preferable. Gas stations are registered in the road network database.
In this way, even when the gas station is used as a transit point, each configuration and function of the route search device 1 is the same as that when the charging station is used as a transit point.

[When the stopover is a resting facility regardless of the vehicle type]
Further, the purpose of stopping at the waypoint on the way to the destination is other than charging the battery and refueling the gasoline as in the electric vehicle of the embodiment. For example, when drivers continue to drive for a long time, fatigue accumulates, so they may stop at service facilities, roadside stations, and other resting facilities. It is also required to search for a recommended route to reach the destination while taking it.

Therefore, the route search apparatus 1 can be used to search for a route to such a destination via the rest facility. In this case, the vehicle may be either an automobile with an internal combustion engine or an electric automobile. The resting facilities serving as transit points mainly include service areas installed on expressways, road stations, and the like, and these resting facilities are registered in the road network database.
When a stopover is considered as a resting place, the driver gradually accumulates fatigue by driving the vehicle. Therefore, a range where the fatigue does not exceed the peak, for example, a range where the vehicle continuously travels for 2 hours is a cruising range ( Setting range). That is, the charge amount of the battery 7 in the embodiment corresponds to the refresh degree of the driver.
And also when using a resting facility as a waypoint in this way, each structure and function of the route search apparatus 1 are the same as the case where a charging station is made a waypoint.

  In addition, embodiment disclosed this time is an illustration and restrictive at no points. The scope of rights of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope equivalent to the configurations described in the claims.

  For example, in each of the above explanations, as conditions for the vehicle to stop at the waypoint, when the electric vehicle stops at the charging station, when the gasoline vehicle stops at the gas station, and when the stop stops regardless of the type of the vehicle, Although described as individual, a waypoint may be determined by combining these conditions. For example, the entire route passing through the waypoint may be searched based on both the cruising range of the vehicle based on the power or fuel of the battery and the fatigue level of the driver. In this case, if the waypoint is determined based on the logical product of the cruising distance and the fatigue level, it is possible to search for an entire route that is not continuously operated and has the most efficient power supply or fuel supply.

1: route search device 2: vehicle 7: battery 11: first search unit 12: second search unit 13: determination unit 15c: database for charging station 18: information input unit E1 to E8: charging station (route)

Claims (10)

A route search device that searches for a recommended route for a vehicle to travel from a departure point to a destination using a link cost of a road link,
A first search unit for obtaining one or more waypoints within a set range starting from the departure point and a section route to the waypoint; and
Section route search processing for obtaining one or more other waypoints within the set range starting from the obtained one or more waypoints and a section route to the other waypoints until reaching the destination A second search unit to be repeated;
A determination unit that determines the recommended route based on a processing result of the second search unit;
A route search device comprising:   The route search device according to claim 1, wherein the first search unit and the second search unit obtain the section route using dynamic information that changes over time.   The second search unit includes the time spent at the determined waypoint in the link cost, and uses traffic information after the time spent at the waypoint as dynamic information that changes over time, The route search device according to claim 2, wherein the route route is obtained.   The second search unit includes a section route having a minimum link cost in the recommended route when a plurality of section routes from a plurality of waypoints as a starting point to one other waypoint exist. The route search device according to any one of claims 1 to 3, wherein the route search device is left as a route candidate. The vehicle is an electric vehicle that has a rechargeable battery and uses the power of the battery as driving power,
The route search device according to any one of claims 1 to 4, wherein the waypoint includes a charging station that charges the battery.   The route search device according to claim 5, wherein the setting range is based on a remaining power amount of the battery. A database for storing charging station attribute information indicating at least one of the location of the charging station, the time required for staying at the charging station, the presence / absence of a quick charging function at the charging station, and the usable time zone of the charging station. And more,
The route search device according to claim 5 or 6, wherein the first search unit and the second search unit search for a section route based on the attribute information.   The route search device according to claim 7, further comprising an information input unit for adding and storing the attribute information in the database.   The second search unit calculates a charging time required to reach a predetermined charging amount from a remaining amount of battery power when the battery arrives at a charging station, and includes the charging time in a link cost to determine the section route. The route search apparatus as described in any one of 5-8. A computer program for causing a computer to execute a process of searching for a recommended route for a vehicle to travel from a starting point to a destination using a link cost of a road link,
Obtaining one or more waypoints within a set range starting from the starting point and a section route to the waypoint; and
Section route search processing for obtaining one or more other waypoints within the set range starting from the obtained one or more waypoints and a section route to the other waypoints until reaching the destination Repeated steps,
Determining the recommended route based on a processing result by the step of repeatedly performing the section route search processing;
A computer program comprising:

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