JP3235307B2 - Route guidance device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a route guidance apparatus for a vehicle which searches for a route from a vehicle position to a destination, finds an optimal route, and guides the vehicle to the destination according to the optimal route.

[0002]

2. Description of the Related Art There is known a vehicular route guidance apparatus that searches for a route from a current position of a vehicle to a destination to obtain an optimum route and displays the optimum route and the current position on a display. Typical methods for performing a route search include the Dijkstra method for performing an omnidirectional search (Japanese Patent Laid-Open No. 62-86499),
There is an A ^* method for performing directivity search, and Japanese Patent Laid-Open No. 2-259999,
No. 2-260,000) discloses an algorithm for shortening the time required for route search. The device described in this publication seeks to shorten the route search time by performing a route search with directivity from both the current position and the destination.

[0003]

Even if the optimum route is found by the route search, if the roads intersect complicatedly or the vehicle cannot pass through the optimum route due to traffic congestion or road construction, etc. You may leave the route. In such a case, since the vehicle continues to travel, unless a new optimal route is calculated and notified to the driver immediately, the vehicle leaves the route more and more. However, since the device described in the above publication calculates the optimum route in the same manner as in a normal route search even when a route departure occurs, the distance between the vehicle position detected after the route departure and the destination is large. In such a case, it takes time to calculate the optimum route.

[0004] On the other hand, there is known an apparatus in which several route search methods are prepared when a route departure occurs, and any one of them can be arbitrarily selected. This apparatus has a route return mode that is selected when the distance of departure from the route (hereinafter, referred to as a route departure amount) is small, and a total route selection mode that is selected when the route departure amount is large or when it is desired to accurately obtain an optimal route. A route calculation mode is provided. When the route return mode is selected, a route for returning the vehicle to the original route is searched, and when the all route calculation mode is selected, all routes between the current position and the destination are searched. I do. Thus, when there is not enough time, the route return mode may be selected, and when there is enough time, the entire route calculation mode may be selected. Route search can be performed.

[0005] However, even if such a selection mode is provided, the driver cannot know exactly how much the route departure amount is, so it is often difficult to determine which mode to select. In addition, since the route determined by the route return mode is not always the optimal route to the destination, the all route calculation mode for calculating the optimal route is preferable, but it may take a considerable time to find the optimal route. is there. Further, it is troublesome to switch the selection mode every time the route leaves.

An object of the present invention is to continuously search for an optimum route from a destination to each intersection from the destination by a second route search means, and to search for a second route when a vehicle leaves the route. An object of the present invention is to provide a vehicular route guidance apparatus that searches for an optimum route using a search result of a means, thereby shortening a route search time when leaving a route.

[0007]

The present invention will be described with reference to FIG. 1 showing an embodiment. The present invention provides a road map storage means 3 for storing road map data including intersection information, and a current position of a vehicle. Vehicle position detecting means 1 and 2 for detecting, destination setting means 7 for setting a destination, first route searching means 4 for searching for an optimal route from the current position to the destination based on road map data, this is applied to a vehicle navigation system and a display unit 9 for displaying the optimum route searched by the first route search unit 4, the peripheral from the destination
A second route searching means 4 for sequentially searching for an optimum route to each intersection from the destination to its surroundings, and whether or not the vehicle has departed from the optimum route searched by the first route searching means 4 A departure determining unit 4 for determining whether the current position of the departed vehicle is within the range searched by the second route searching unit 4, and an optimal route by the departure determining unit 4. It is determined that the vehicle has departed from the vehicle , and the current position is
If it is determined that the route is not within the search range of the route search means 4, a search for an optimal route from the current position after the departure to the destination is made based on the search result by the second route search means 4 and the road map data. The above object is achieved by providing the third route search means 4. The invention described in claim 2 is
In the vehicle route guidance device according to the first aspect, the third route search means 4 is configured to search until reaching the intersection searched by the second route search means 4. The invention described in claim 3 is claim 1 or
In the vehicle route guidance device according to claim 2 , the first route search unit 4, the second route search unit 4, and the third route search unit 4 are configured to search for a route with the shortest vehicle travel time. Make up. According to a fourth aspect of the present invention, in the vehicle route guidance apparatus according to the first or second aspect , the first route searching means 4 and the second route searching means 4 search for a route having the shortest vehicle traveling distance. Route search means 4
And the third route search means 4.

[0008]

According to the first aspect of the present invention, a destination and its surroundings are located.
The second route search means 4 searches for an optimum route to each intersection of the side, and the departure determination means 4 determines whether or not the vehicle has departed from the optimum route searched by the first route search means 4. . The departure determining means 4 determines whether or not the vehicle has departed from the optimal route searched by the first route searching means 4, and the current position determining means 4 searches for the departed vehicle by the second route searching means 4. It is determined whether or not it is within the specified range. The departure determination means 4 determines that the vehicle has departed from the optimum route , and the current location determination means 4 determines that the current location is the second route search means 4.
Is determined to be out of the search range , the third route searching means 4 determines the optimum route from the current position after the departure to the destination based on the search result by the second route searching means 4 and the road map data. , The route search time is greatly reduced. According to the second aspect of the present invention, since the search is performed by the third route searching means 4 until the vehicle reaches the intersection searched by the second route searching means 4, the route searching time can be reduced.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0010]

FIG. 1 is a block diagram of a vehicle route guidance apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an azimuth sensor, which detects a traveling azimuth of a vehicle by detecting, for example, geomagnetism at a position where the vehicle exists. Reference numeral 2 denotes a vehicle speed sensor which is attached to, for example, a transmission of the vehicle and outputs a predetermined number of pulse signals according to the vehicle speed. 3
Is a map storage memory for storing road map data including intersection network data, such as road type information such as expressways and national roads, intersection connection road information, distance information between intersections, road width information, and text information such as place names. Is stored. Reference numeral 4 denotes a CPU that performs calculation of an optimal route from the departure point of the vehicle to the destination, processes of FIGS. The CPU 4 also controls various sensors and controllers (not shown) in the vehicle. 5 is CPU4
For storing a control program executed by the computer
M and 6 are RAMs for storing route search results by the CPU 4
It is. Reference numeral 7 denotes an operation board for inputting a destination of the vehicle, and 8 denotes a V- which stores image data generated by the CPU 4.
The data stored in the V-RAM 8 is displayed on a display 9.

In the route guidance apparatus for a vehicle configured as shown in FIG. 1, the CPU 4 measures the number of pulses or the pulse period per unit time output from the vehicle speed sensor 2 while the vehicle is running, thereby determining the running speed of the vehicle. , And the running distance of the vehicle is detected by measuring the number of pulses. Next, the CPU 4 calculates the traveling locus of the vehicle based on the detected vehicle traveling distance and the traveling direction of the vehicle detected by the direction sensor 1, and performs map matching with the road map data stored in the map storage memory 3. Go to determine the current location of the vehicle. Next, the CPU 4 calculates an optimal route from the current position of the vehicle to the destination based on the known Dijkstra method or the like.

Thereafter, the CPU 4 performs an omnidirectional search by the known Dijkstra method according to the flowcharts of FIGS. Hereinafter, the operation of the flowcharts of FIGS. The omnidirectional search shown in FIGS. 2 and 3 is performed centering on the destination, and is continuously executed using the idle time of the CPU 4 until an ignition key (not shown) is turned off. In step S1 of FIG. 2, the last intersection is specified.
This final intersection, as disclosed in, for example, Japanese Patent Application Laid-Open No. 62-86499, is located outside the circle of a predetermined radius centered on the destination from the intersections around the destination, and Is selected as the final intersection.

In step S2, the last intersection is set as the center intersection. Here, the central intersection refers to an intersection to be searched. In step S3, 0 is set for the route h of the last intersection.
And set a very large value + ∞ for the journey h at all other intersections. Here, the distance h means the distance from the last intersection to another intersection. In addition, all flags provided for each intersection, which indicate that the route search has been completed, are set to “0”. In step S4, any one of the intersections adjacent to the central intersection is selected as the adjacent intersection. In step S5, as shown in FIG. 4A, the travel distance h of the center intersection and the step S
The value obtained by adding the distance to the adjacent intersection selected in 4 is
It is determined whether the distance is smaller than the distance h of the adjacent intersection. If the determination is affirmative, the process proceeds to step S6, and the value added in step S5 is set as the route h of the adjacent intersection.

In step S7 in FIG. 3, it is determined whether or not the current adjacent intersection exists in the center intersection candidate list A. Here, the center intersection candidate list A is a list in which intersection numbers that can be the center intersection are described. If the determination is negative, the process moves to step S8, and the adjacent intersection is added to the center intersection candidate list A. In step S9, the current center intersection is set as the intersection A immediately before the adjacent intersection. Here, the immediately preceding intersection is an intersection that is the smallest intersection with the adjacent intersection and that has a smaller distance h than the adjacent intersection.

In step S10, it is determined whether or not the processing in steps S4 to S9 has been performed for all adjacent intersections. If the determination is negative, the process returns to step S4, and if the determination is positive, the process proceeds to step S11. Step S
At 11, it is determined whether or not the center intersection candidate list A is empty. If the determination is affirmative, the process ends, and if the determination is negative, the process proceeds to step S12. In step S12,
An intersection having the smallest distance h in the center intersection candidate list A is set as a new center intersection.

In step S13, the center intersection newly selected from the center intersection candidate list A is deleted. In step S14, the flag of the center intersection immediately before performing the process of step S12 is set to "1", and the process returns to step S4.
When this flag becomes “1”, it indicates that the route h has been obtained for the intersection, that is, the route search for the intersection has been completed.

In summary of the operations of the flowcharts of FIGS. 2 and 3 described above, initialization is performed in steps S1 to S3, and a process h for updating the distance h of the adjacent intersection is performed in steps S4 to S7. In steps S8 to S10, registration to the central intersection candidate list A and setting of an intersection just before an adjacent intersection are performed. After performing the processing of steps S4 to S9 for all the intersections adjacent to the center intersection, in step S12, the intersection having the smallest distance h in the center intersection candidate list A is set as the center intersection. Steps S4 to S10 are repeated until the ignition key is turned off or the center intersection candidate list becomes empty.

For example, before starting the processing of FIGS.
When the optimal route calculated by the PU 4 is a thick line portion in FIG. 4A, the processing in FIGS. 2 and 3 is performed for a predetermined time, so that the range of the search area A indicated by the oblique line in FIG. A route search is performed. After more time,
As shown in FIG. 4C, the area of the search area A increases.

On the other hand, the CPU 4 performs the route leaving / returning process shown in FIGS. In this route departure return processing, it is determined whether or not the vehicle has departed from the route, and a route search from the vehicle position where the route has departed to the destination is performed. In step S101 in FIG. 5, it is determined whether the vehicle has left the route. This determination is made by comparing the current position of the vehicle obtained by the direction sensor 1 and the vehicle speed sensor 2 with the optimum route data stored in the RAM 6. If the determination in step S101 is negative, the process ends, and if the determination is positive, the process proceeds to step S102,
As in step S1 of FIG. 2, an intersection close to the current location of the vehicle is specified as a departure intersection. Step S103
Then, it is determined whether or not the departure intersection flag is “1”. When this flag becomes “1”, it indicates that the route search from the destination has already been completed for the current intersection to be searched (here, the departure intersection).

If the determination in step S103 is affirmative, that is, if the route search has been completed, the process proceeds to step S104, and immediately before the departure intersection selected in step S102 is obtained in the processing in FIGS. The route up to the target intersection by sequentially tracing the intersection A is stored in the RAM 6 as a new optimum route, and the process is terminated. That is, even if the vehicle has left the route, as shown in FIG. 8A, if the route search at the current location (the arrow mark in the drawing) of the vehicle has already been completed, a new route search is performed. The process ends without executing. Therefore, the route search process can be omitted, and the optimum route can be immediately displayed on the display 9 based on the search results of FIGS. On the other hand, FIG.
As shown in (b), when the vehicle position after leaving the route is outside the search area A, step S10 described below.
5 and thereafter, the search area B indicated by oblique lines in FIG.
A route search is performed for the range of.

If the determination in step S103 in FIG. 5 is negative, the process moves to step S105, and the departure intersection is set as the center intersection. In step S106, the distance g of the departure intersection is set to 0, and the distance g of the other intersections is set to a very large value + ∞. The distance g means the distance from the departure intersection to another intersection. Step S10
At 7, one of the intersections adjacent to the central intersection is selected. In step S108, as shown in FIG. 9A, it is determined whether or not a value obtained by adding the distance g from the center intersection to the distance from the center intersection to the adjacent intersection is smaller than the distance g from the adjacent intersection. If the determination is affirmative, the process proceeds to step S109, and the value added in step S108 is set as the distance g of the adjacent intersection.

In step S110, the center intersection is set as the intersection B immediately before the adjacent intersection. Step S11
At 1, it is determined whether or not the flag of the adjacent intersection is “1”. The flag of the adjacent intersection becomes “1” when the route search from the final intersection is completed for the adjacent intersection, that is, when the adjacent intersection is located in the search area A as shown in FIG. Yes, in this case, the process proceeds to step S112 in FIG.

In step S112, the distance h of the adjacent intersection (the distance from the last intersection to the adjacent intersection) obtained by the processing of FIGS. 2 and 3 and the distance g of the adjacent intersection obtained in step S110 (the distance g from the departure intersection to the center intersection) It is determined whether or not the value obtained by adding the distance to the adjacent intersection through the route is smaller than the distance g of the final intersection. If the determination is affirmative, the process proceeds to step S113, and a value obtained by adding the distance g of the adjacent intersection and the distance h of the adjacent intersection is set as the distance g of the final intersection. In step S114, the current adjacent intersection is set as the intersection B immediately before the last intersection. Here, the reason why an adjacent intersection is set as an intersection immediately before the final intersection, even though there are a plurality of intersections between the adjacent intersection and the final intersection, is to search for a contact intersection to be described later.

In step S115, it is determined whether or not the last intersection exists in the center intersection candidate list B. If the determination is negative, the process proceeds to step S116, where the final intersection is registered in the central intersection candidate list B, and the process proceeds to step S116 in FIG.
Move to 119.

On the other hand, if the determination in step S111 in FIG. 5 is negative, that is, if the current adjacent intersection is not located within the search area A as shown in FIG. 9A, the process proceeds to step S117 in FIG. It is determined whether or not the adjacent intersection exists in the center intersection candidate list B. If the determination is negative, the process proceeds to step S118, where the adjacent intersection is additionally registered in the center intersection candidate list B, the straight-line distance from the target intersection to the adjacent intersection is calculated, and the value is calculated as the estimated travel distance h ′.
Record as Further, the route g from the central intersection to the adjacent intersection is stored in the RAM 6, and the process proceeds to step S119 in FIG.
Move to

If the determination in step S108 in FIG. 5 is denied, the process also proceeds to step S119 in FIG. 7, and it is determined whether or not the processes in steps S107 to S118 have been performed for all adjacent intersections. Then, the process proceeds to step S120. In step S120, an intersection having the smallest (g + h ′) is selected from the center intersection candidate list B as a new center intersection. Step S12
In step 1, the intersection selected in S120 is deleted from the center intersection candidate list B. In step S122, it is determined whether or not the new center intersection is the last intersection. If the determination is negative, the process returns to step S107 in FIG.

The search area B shown in FIG. 9A gradually expands in the direction of the destination by continuing the processing of steps S107 to S122, and if the determination in step S122 is affirmed, the search area B shown in FIG. It becomes the size shown in.

If the determination in step S122 is affirmative, the process proceeds to step S123, where the intersection just before the departure intersection is set as the contact intersection. The contact intersection is an intersection that switches the route search direction. That is, from the contact intersection to the destination, the route search result by the processing of FIGS. 2 and 3 (search area A shown in FIG. 9C), and from the one contact intersection to the current location of the vehicle, the route by the processing of FIGS. The optimum route is obtained based on the search result (search area B shown in FIG. 9C).

In step S124, a route from the contact intersection to the last intersection is obtained by sequentially tracing the immediately preceding intersection A from the contact intersection. In step S125, a route from the junction intersection to the departure intersection is obtained by sequentially tracing the immediately preceding intersection B from the junction intersection. Step S
At 126, the results of steps S124 and S125 are combined to determine the optimal route from the departure intersection to the final intersection, and the result is stored in the RAM 6,
The information is displayed on the display 9 and the process ends.

As described above, when the processes in the flowcharts of FIGS. 5 to 7 are summarized, it is determined in step S101 whether or not the route has left, and initialization is performed in steps S102 to S106. In steps S107 to S110, the route g of the adjacent intersection and the intersection immediately before the adjacent intersection are updated. In step S110, it is determined whether or not the adjacent intersection is located within the search area A. If the determination is affirmative, step S112 is performed.
Through step S116, the route g of the final intersection and the intersection immediately before the final intersection are updated. On the other hand, step S110
Is negative, registration of the adjacent intersection in the center intersection candidate list B and calculation of (g + h ′) of the adjacent intersection are performed in steps S117 and S118. Step S10 is performed for all intersections adjacent to the central intersection.
After performing the processing of 7 to S118, the intersection having the minimum (g + h ′) is selected from the center intersection candidate list B in step S120, and the processing of steps S107 to S121 is repeated. If the center intersection coincides with the final intersection, a contact intersection is set in step S123, and step S124
The optimal route is obtained through S126.

As described above, in the above-described embodiment, once the vehicle starts running, the omnidirectional route search centering on the destination is performed using the idle time of the CPU 4, and the vehicle leaves the route. Is periodically detected. When the vehicle departs from the route, it is determined whether or not the vehicle is located within the range in which the omnidirectional route search was performed. If the vehicle is located within the range, the omnidirectional search is performed. Since the optimum route is determined based on the result, a new route search does not need to be performed. On the other hand, when the vehicle is not located within the omnidirectional route search range, the route search is performed by making full use of the omnidirectional route search range, so that the time required for the route search is significantly reduced. You.

In the flowcharts of FIGS. 2 and 3, a non-directional route search is performed, but a directivity search by the A ^* method or the like may be performed. In the flowcharts of FIGS. 5 to 7, the route search is performed from the vehicle position where the route departure is detected.
For example, when the vehicle is traveling on a road with few intersections, a future traveling position of the vehicle is predicted using the direction sensor 1, the vehicle speed sensor 2, and the like, and processing of the diagram is started from the predicted position. Is also good. In this way, the vehicle can be properly guided even if the processing in FIGS. Also, when the vehicle has left the route, a warning display or a warning sound is generated, and when a new route is calculated, it is displayed in a different color from the conventional optimal route to alert the driver. You may be prompted. In the above-described embodiment, a route that minimizes the vehicle travel distance to the destination is searched for, but a route that minimizes the vehicle travel time to the destination may be searched for.

In the embodiment configured as described above,
The map storage memory 3 stores the direction sensor 1 in the road map storage means.
And the vehicle speed sensor 2 as the vehicle position detecting means, the operation board 7 as the destination setting means, the CPU 4 as the first route searching means, the display 9 as the display means, and FIGS. 2 and 3 as the second route searching means. 5, step S101 in FIG. 5 corresponds to the departure determination unit, and step S111 in FIG.
7 correspond to the third route searching means, respectively.

[0034]

As described [Effect Invention above in detail, according to the present invention, the peripheral from the destination by the second route search means
The vehicle continues to search for the optimal route to each intersection, and the vehicle departs from the optimal route searched by the first route searching means.
And, and, the current position at the time of route withdrawal if not in the range which is searched by the second route search means, after leaving on the basis of the search result and the road map data of the second route search means
Since the optimal route from the current location to the destination is searched, the route search time can be greatly reduced.

[Brief description of the drawings]

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

FIG. 2 is a flowchart of an omnidirectional search by a CPU.

FIG. 3 is a flowchart following FIG. 2;

FIG. 4 is a diagram illustrating an example of a route search.

FIG. 5 is a flowchart illustrating a route departure return process performed by a CPU.

FIG. 6 is a flowchart following FIG. 5;

FIG. 7 is a flowchart following FIG. 6;

FIG. 8 is a diagram illustrating an example of route departure.

FIG. 9 is a diagram showing a search range by the processing of FIGS.

[Explanation of symbols]

 Reference Signs List 1 direction sensor 2 vehicle speed sensor 3 map storage memory 4 CPU 5 ROM 6 RAM 7 operation board 8 V-RAM 9 display

Continuation of front page (56) References JP-A-6-68382 (JP, A) JP-A-5-45170 (JP, A) JP-A-4-280287 (JP, A) JP-A-3-219397 (JP JP-A-3-127199 (JP, A) JP-A-1-173815 (JP, A) JP-A-61-38518 (JP, A) JP-A-2-99310 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969 G09B 29/10

Claims (4)

(57) [Claims] 1. Road map storage means for storing road map data including intersection information; vehicle position detection means for detecting a current position of a vehicle; destination setting means for setting a destination; A first route searching means for searching for an optimum route from the current location to the destination; and a display means for displaying the optimum route searched by the first route searching means. the optimum path from the earth to the intersection of the peripheral, the second route search means for successively searching toward its periphery from the destination, the vehicle from the optimum route searched by the first route search means Departure determination means for determining whether or not the vehicle has left; current position determination means for determining whether the current location of the departed vehicle is within a range searched by the second route search means. The vehicle from the optimum path by the deviation judgment unit is determined to be disengaged, and current position by said current position determining means
If it is determined that the route is not within the search range of the second route search means, the optimal route from the current position after the departure to the destination is determined based on the search result by the second route search means and the road map data. And a third route searching means for searching for a vehicle. 2. The vehicle route guidance device according to claim 1, wherein the third route searching means performs a search until reaching an intersection searched by the second route searching means. Route guidance device for vehicles. 3. The vehicle route guidance device according to claim 1 , wherein the first route search unit, the second route search unit, and the third route search unit are configured to drive the vehicle. A route guidance device for a vehicle, which searches for a route with the shortest time. 4. The vehicle route guidance device according to claim 1 , wherein the first route search unit, the second route search unit, and the third route search unit are configured to drive the vehicle. A vehicle route guidance device for searching for a route having the shortest distance.