JP3328091B2 - Route guidance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention uses a map database to search for an optimum route from a current position of a host vehicle to a predetermined travel destination, and the route of the host vehicle along the optimum route obtained by the search. The present invention relates to a route guidance device that performs guidance.

[0002]

2. Description of the Related Art In recent years, a route guidance device (navigation device) has been mounted on an automobile in order to assist a vehicle in traveling on unfamiliar land. This route guidance device is generally based on a setting operation of a vehicle occupant, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-129800.
Using a map database that stores a wide range of road networks and other map data, a search for an optimal route from the current position of the vehicle to a predetermined travel destination is performed. Are sequentially presented to guide the route of the own vehicle.

[0003] The search for the optimum route is performed by mapping a travel route that minimizes a travel route loss (that is, a desired travel impediment factor such as a loss of travel time, a loss of travel distance, and a loss of ease of travel). It is common to search from a database. For example, in the route guidance device described in the above publication, a travel route that minimizes the required travel time from the current position of the vehicle to the travel destination is searched from the map database as an optimal route.

By the way, even when a route is guided along the optimal route obtained by the above search, the vehicle may deviate from the optimal route due to a driver's error or the like. In this case, it is necessary to search for a new optimal route again for route guidance, but this re-search is performed as a new search for the optimal route from the departure point to the final travel destination. In such a case, there is a problem that the time required for the re-search becomes long, and a new route guidance cannot be promptly performed.

[0005] On the other hand, when the vehicle deviates from the optimal route, a search is made for a return route for returning the vehicle to the original optimal route, and the return route obtained by this search is replaced with a new optimal route. If set as a part, the return route search is performed only in the area near the departure point, so that the speed of re-search can be increased. When the return route search is performed, the original optimal route is used as it is as the travel route to the travel destination after the vehicle has returned to the original optimal route along the return route obtained by the search. Becomes Japanese Patent Application Laid-Open No. 6-68382 discloses a route guidance device capable of executing the return route search.

[0006]

In the route guidance apparatus disclosed in the above-mentioned publication, at the time of departure from a route, one of a search for an entire route to a travel destination and a search for a return route to an original optimum route is performed. Is selected by the switch operation of the vehicle occupant. In this way, if the return route search is automatically performed according to the route departure without relying on the switch operation, a new optimal route can be selected in real time. Can start a search again.

However, in such a case,
There are the following problems.

That is, when the vehicle is traveling at a high speed, or when the road is closely adjacent and the distance to the next intersection is short, it is necessary to search for a return route more quickly. In addition, there is a problem that it is difficult to shorten the return route search time to some extent.

On the other hand, Japanese Patent Application Laid-Open No. 4-178682 discloses that before an own vehicle departs, an optimal route is searched in a reverse direction from a traveling destination to a current position of the own vehicle. Route guidance device configured to hold the optimal route obtained by the above and other route data obtained in the search process, so that a new optimal route can be searched instantaneously when the route deviates. Is disclosed.

However, when the route data obtained by such a search before departure is used, real-time information such as traffic congestion information cannot be reflected in a new optimum route search. May not be the true optimal route. In addition, the reverse search from the travel destination to the current position of the vehicle is performed over a wide range, and it is difficult to perform the search using road network data with a high level of road network detail. Sometimes, when the approached road is a narrow road such as a living road, there may be a case where the entered road does not exist in the route data obtained in the reverse search process, in such a case, There is a problem that a new optimal route search cannot be performed.

The present invention has been made in view of such circumstances, and in a case where a new optimal route is re-searched when the route deviates from the optimal route, the re-search is appropriately and appropriately performed. It is an object of the present invention to provide a route guidance device that can be performed in a short time.

[0012]

According to the present invention, a return route search is performed in advance for a route deviation that may occur in the future while traveling on the optimum route, instead of performing a return route search after deviating from the optimum route. Thus, the time required for the return route search when a route deviation actually occurs is made substantially zero, thereby achieving the above object.

[0013] That is, the route guidance device according to the present invention, as described in claim 1, includes a route search means for searching for an optimum route from the current position of the vehicle to a predetermined travel destination using a map database. Route guidance means for guiding the vehicle along the optimal route obtained by the search, wherein when the vehicle is traveling along the optimal route, Return route preliminary search means for searching for a return route for returning the vehicle to the optimal route on the assumption that the vehicle deviates from the optimal route at a predetermined point; and a return route obtained by the search. Storage means for storing, when the vehicle deviates from the optimum route, return route selecting means for selecting a return route corresponding to the road entered by the departure from the stored return routes; A return path and a best path re-setting means for setting as part of a new optimum path,
It is characterized by the following.

The above-mentioned "predetermined point ahead of the own vehicle" means a point such as an intersection located ahead of the own vehicle on the optimum route and a point where the own vehicle may deviate from the optimum route in the future. It is.

[0015]

As described above, according to the present invention, when the own vehicle is traveling along the optimum route, a return route search is performed on the assumption that the vehicle deviates at a predetermined point ahead of the own vehicle. In addition, the return route obtained by this search is stored, and when a route deviation actually occurs, a return route corresponding to the departure approach road is selected from among the stored return routes, and the selected return route is selected. Since the route is set as a part of the new optimum route, the return route search when a route deviation actually occurs can be performed only by performing the return route selection process, and thereby the return route search is performed. The required time can be made substantially zero.

Therefore, according to the present invention, when a new optimal route is re-searched when the route deviates from the optimal route, the re-search can be performed appropriately and in a short time. Thus, appropriate route guidance at the time of departure from the route can be instantaneously performed.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a vehicle route guidance apparatus according to the present invention.

This route guidance device 10 is a device mounted on an automobile, and as shown in FIG.
It includes a map database 14, a locator 16, a traffic information receiving device 18, a destination input unit 20, a display unit 22, and an audio output unit 24.

The arithmetic processing unit 12 is a route search unit 2 for searching for an optimal route from the current position of the vehicle to a predetermined travel destination.
6 and a route guidance unit 28 that guides the vehicle along the optimum route obtained by the search by the route search unit 26.

The map database 14 is a database storing a wide range of road networks and other map data, and is accessible from a route search unit 26 and a route guidance unit 28. The road network data in the map database 14 is a plurality of layers of road network data having different levels of road network detail. The road network data of each layer includes a plurality of nodes (nodes such as intersections) and a plurality of nodes between the nodes. (The minimum unit of the traveling path).

The locator 16 is a device for detecting the current position of the vehicle, and is configured to detect the current position of the vehicle by a known method using a GPS receiver, a gyro, a geomagnetic sensor, or the like. The data of the current position of the vehicle detected by the locator 16 is output to the route search unit 26 and the route guidance unit 28.

The traffic information receiving device 18 receives traffic information such as traffic congestion information and road construction information from the outside.

The destination setting section 20 sets a travel destination by voice input or manual input using a touch panel or the like.

The optimum route search by the route search unit 26 is performed using the road network data of the map database 14 and the traffic information received by the traffic information receiving device 18. In this optimal route search, a process for finding an optimal traveling route that minimizes a traveling route loss from the current position of the vehicle to the traveling destination is performed. The travel route loss impairs the ease of traveling such as the cost set for each link (that is, the time required for traveling through the link (travel time), the road width of the link, the slope, the presence or absence of pavement, etc.). ) Is calculated as a cumulative value.

The route guidance unit 28 sequentially presents the route data of the optimal route obtained by the search by the route search unit 26 to the driver according to the current vehicle traveling position, and performs the route guidance. . That is, the current position of the vehicle is traced while highlighting the optimum route on the map on the display unit 22, and the voice output unit 24 gives a voice route instruction.

As shown, the route search unit 26 includes a return route search unit 30, and the route guidance unit 28 includes a route deviation determination unit 32.

The return route searching section 30 assumes that, when the vehicle is traveling along the optimal route, the vehicle deviates from the optimal route at each node ahead of the vehicle on the optimal route.
For each of them, a search for a return route for returning the vehicle to the optimum route is performed, and the return route obtained by the return route preliminary search is stored.

The route deviation determining unit 32 compares the route data of the optimal route with the data of the current position of the vehicle detected by the locator 16 to determine whether the vehicle deviates from the optimal route. If it deviates, it requests the route search unit 26 for new route data.

Upon receiving the new route data request, the route search unit 26 selects a return route corresponding to the road that has entered due to the departure from the return routes stored in the return route search unit 30, and this selected route is selected. The return route is set as a part of the new optimal route. That is, a route connecting the return route obtained by the above-described return route selection and a portion from the return point by the return route to the travel destination in the original optimal route is set as a new optimal route. ing. Then, the route search unit 26
The newly set optimal route is output to the route guidance unit 28 as new route data. The route guidance unit 28 guides the vehicle according to the return route data of the new route data and returns to the optimal route.

Next, the operation of the present embodiment will be described.

First, basic processing contents of the route guidance in this embodiment will be described with reference to the flowchart of FIG.

As shown in the figure, when the travel destination is set (step S1), the optimum route from the current position of the vehicle to the travel destination is searched (step S2), and the optimum route obtained by the search is obtained. The vehicle is guided along (step S3). Then, while performing the route guidance, the return route preliminary search is sequentially performed, and the result is stored (steps S4 and S5). If the vehicle arrives at the travel destination by the route guidance, the route guidance is terminated.
6, S7). If the vehicle has not deviated, the route guidance is continued, and if the vehicle has deviated, a return route corresponding to the departure approach road is selected from the stored return routes (step S8). Then, after the selected return route is set as a part of the new optimum route (step S9), the process returns to step S3 to perform route guidance again.

The return route preliminary search is specifically performed as follows. That is, as shown in FIG. 3, a plurality of stopovers I are set at appropriate intervals on the optimal route. Then, when the own vehicle passes through a certain waypoint I _i-2 , the vehicle arrives at the next waypoint I _i-1 by using the Dijkstra method or the A ^* algorithm. _A route search is performed with _i as the starting point and the via point I _i-1 as the destination (that is, in a direction opposite to the normal optimum route search performed by the route searching unit 26). This search process is performed until a route having a predetermined cost is searched after the route to the route point I _i-1 is searched (that is, the route slightly exceeds the route point I _i-1 as indicated by the broken line in the figure). The range of the search extends to the point where it was). By this return route preliminary search,
To possible route deviation at each node that exists between the route point I _i-1 ~ waypoint I _i, so that the return route to the waypoint I _i from the route departure point is obtained.

The above-mentioned return route preliminary search is sequentially performed in preparation for a route departure between the next via points each time the vehicle passes through each via point I. That is, transit point I
When traveling between _i-2 and transit point _{i i-1} , transit point _i-1
Return route preliminary search is provided in the path deviations may occur between the route point I _i is performed, the next way point _i ~ stopover I _i when traveling between the route points _i-1 ~ waypoint I _{i A} return route preliminary search is performed in preparation for a possible route deviation between ₊₁ . In the case of a highway or the like, the stopover I is not set between the entrance and the next entrance.

As described above in detail, in the present embodiment, when the own vehicle is traveling along the optimum route, the return route search is performed successively on the assumption that the vehicle deviates at a predetermined point ahead of the own vehicle. The return route obtained by this search is stored, and when a route deviation actually occurs, a return route corresponding to the departure approach road is selected from the stored return routes, and the selected return route is selected. Is set as a part of the new optimal route, so that when the route actually deviates, the return route can be searched for only by performing the return route selection process. Time can be reduced to almost zero.

Therefore, according to the present embodiment, when re-search for a new optimum route is performed when the route deviates from the optimum route, the re-search can be performed appropriately and in a short time. Thus, appropriate route guidance at the time of departure from the route can be instantaneously performed.

In the above embodiment, the return route preliminary search is performed as a reverse route search in a direction opposite to the traveling direction of the own vehicle. The return route preliminary search may be performed as a forward route search from a possible point toward the traveling direction of the vehicle. When this forward route search is adopted, return routes from points where there is a possibility of route deviation ahead of the own vehicle are sequentially searched from the near side without setting the waypoint I as in the above embodiment. You can also do so.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a route guidance device according to the present invention.

FIG. 2 is a flowchart showing basic processing contents of route guidance in the embodiment.

FIG. 3 is a diagram showing a specific example of a return route preliminary search process in the embodiment.

[Explanation of symbols]

Reference Signs List 10 route guidance device 12 arithmetic processing unit 14 map database 16 locator 18 traffic information receiving device 20 destination input unit 22 display unit 24 voice output unit 26 route search unit 28 route guidance unit (return route selection unit, optimal route resetting unit) 30 return route search section (return route preliminary search means, storage means) 32 route departure determination section

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-174577 (JP, A) JP-A-3-219397 (JP, A) JP-A-63-163210 (JP, A) JP-A 8- 30193 (JP, A) JP-A-7-129888 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 21/00-21/36 G08G 1/0969 G09B 29/00- 29/10

Claims (1)

(57) [Claims] 1. A route searching means for searching for an optimum route from a current position of a vehicle to a predetermined travel destination using a map database, and a route for guiding the vehicle along the optimum route obtained by the search. A route guidance device comprising: a guidance device, wherein when the vehicle is traveling along the optimal route, the vehicle deviates from the optimal route at a predetermined point in front of the vehicle. Return route preliminary search means for searching for a return route for returning the vehicle to the optimal route; storage means for storing the return route obtained by the search; and when the vehicle deviates from the optimal route, Return route selection means for selecting a return route corresponding to the road entered due to the departure from the stored return routes; and an optimal route resetting means for setting the selected return route as a part of a new optimal route. And a preparative It navigation system according to claim.