JPH07174577A - Route guidance apparatus for vehicle - Google Patents

Abstract

PURPOSE:To shorten the search time of an optimum route when a vehicle is deviated from the route by searching the optimum route from a destination up to every crossing in its periphery continuously. CONSTITUTION:The route guidance apparatus for a vehicle is provided with a direction sensor 1, a vehicle-velocity sensor 2, a map storage memory 3, a CPU 4, a ROM 5, a RAM 6, a V-RAM 8 and a display 9. The CPU 4 first operates an optimum route up to a destination from a present point, and the vehicle is guided according to the route. When the vehicle starts to run, the CPU 4 operates an optimum route from the destination by utilizing an empty time. In addition, the CPU 4 periodically detects whether the vehicle has been deviated from the optimum route. When it has been deviated from the route, a new route is not searched as long as a route up to a present point has already been searched. On the other hand, when the route up to the present point is not searched, a range in which the route has already been searched is utilized to the full, and the route is searched. As a result, the search time of the route is shortened when the route is deviated from the optimum route.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a route guide device for a vehicle which searches a route from a vehicle position to a destination to find an optimum route and guides the vehicle to the destination according to the optimum route.

[0002]

2. Description of the Related Art A route guidance device for a vehicle is known which searches a route from a current position of a vehicle to a destination to find an optimum route and displays the optimal route and the current position on a display. The Dijkstra method (Japanese Patent Laid-Open No. 62-86499) that performs an omnidirectional search is a typical method for performing a route search,
There is an A ^* method for performing a directional search, and there is also Japanese Patent Laid-Open No. 2-259999,
Japanese Laid-Open Patent Publication No. 2-260000) discloses an algorithm for shortening the time for route search. The device described in this publication attempts to shorten the route search time by performing route search with directivity from both the present location and the destination.

[0003]

Even if the optimum route is found by the route search, if the road is complicatedly crossed or if the vehicle cannot pass through the optimum route due to traffic congestion, road construction, etc., the vehicle is optimal. May leave the route. In such a case, the vehicle continues to travel, and unless the driver immediately calculates a new optimum route and informs the driver, the vehicle will leave the route more and more. However, since the device described in the above publication calculates the optimum route in the same manner as in the case of 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 this case, it takes time to calculate the optimum route.

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 device is selected for the route return mode selected when the distance from which the route has departed (hereinafter referred to as the amount of route departure) is small, and when the amount of route departure is large or when it is desired to accurately obtain the optimum route. A route calculation mode is provided, and when the route return mode is selected, a route for returning the vehicle to the original route is searched, and when all route calculation modes are selected, all routes between the current position and the destination are searched. To do. As a result, the route return mode may be selected when there is not enough time, and the all-routes calculation mode may be selected when there is enough time. You can search the route.

However, even if such a selection mode is provided, the driver cannot accurately know how much the route departure amount is, so that it is often difficult to decide which mode should be selected. In addition, the route determined by the route return mode is not always the optimal route to the destination, so it is preferable to use the all-routes calculation mode to calculate the optimal route, but it may take a considerable amount of time before the optimal route is obtained. is there. Furthermore, it is troublesome to switch the selection mode each time a route departure occurs.

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

[0007]

The present invention will be described with reference to FIG. 1 showing an embodiment. In the present invention, a road map storage means 3 for storing road map data including intersection information and a present location of a vehicle are shown. Vehicle position detecting means 1 and 2 for detecting, destination setting means 7 for setting a destination, first route searching means 4 for searching an optimum route from the current position to the destination based on the road map data, It is applied to a vehicle route guidance device including a display unit 9 for displaying the optimum route searched by the first route search unit 4, and an optimum route from the destination to each intersection to the surroundings is determined from the destination. The second route searching means 4 for sequentially searching toward the periphery thereof, the departure determining means 4 for determining whether or not the vehicle has departed from the optimum route searched by the first route searching means 4, and the departure The current location of the vehicle is A current location determination means 4 determines whether it is within a range which is searched by the route searching means 4,
When it is determined by the departure determination means 4 that the vehicle has left, and when it is determined by the current location determination means 4 that the current location has not been searched, based on the search result by the second route search means 4 and the road map data, The above-mentioned object is achieved by including the third route searching means 4 which searches for the optimum route to the destination. The invention according to claim 2 is, in the vehicle route guiding apparatus according to claim 1, the third route searching means 4 so as to perform the search until reaching the intersection searched by the second route searching means 4. It is what constitutes. The invention according to claim 3 is the claim 1
In the vehicle route guiding device described in 1), the first route searching means 4, the second route searching means 4, and the third route searching means 4 are arranged so as to search for a route in which the vehicle travel time is the shortest.
It is what constitutes. According to a fourth aspect of the invention, in the vehicle route guiding apparatus according to the first aspect, the first route searching means 4 and the second route searching means 4 are arranged so as to search for a route having the shortest vehicle travel distance. And the third route search means 4.

[0008]

According to the first aspect of the present invention, the optimum route from the destination to each intersection to the surroundings is the second route searching means 4
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. Then, 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, and the present location determination means 4 searches for the departed vehicle by the second route search means 4. It is determined whether or not it is within the range. Departure determination means 4
When it is determined that the vehicle has departed and the current location determination means 4 determines that the vehicle has not been searched for, the third route search means 4 is based on the search result by the second route search means 4 and the road map data. Then, since the optimum route from the current position to the destination is searched, the route search time is greatly shortened. According to the second aspect of the invention, since the third route searching means 4 performs the search until the intersection found by the second route searching means 4 is reached, the route searching time can be shortened.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. It is not limited to.

[0010]

1 is a block diagram of an embodiment of a vehicle route guiding apparatus according to the present embodiment. In FIG. 1, reference numeral 1 denotes an azimuth sensor, which detects the traveling azimuth of the vehicle by detecting the geomagnetism at the 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. Three
Is a map storage memory that stores road map data including intersection network data, such as road type information such as highways and national roads, intersection connecting road information, distance information between intersections, road width information, and character information such as place names. Is remembered. Reference numeral 4 denotes a CPU that performs calculation of an optimum route from the starting point of the vehicle to the destination and processes of FIGS. The CPU 4 also controls various sensors (not shown) and controllers in the vehicle. 5 is CPU 4
RO storing the control program executed by the
M and 6 are RAMs for storing the route search result by the CPU 4.
Is. 7 is an operation board for inputting the destination of the vehicle, and 8 is a V- for storing the image data generated by the CPU 4.
This is a RAM, and the data stored in this V-RAM 8 is displayed on the display 9.

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

After that, the CPU 4 performs an omnidirectional search by the known Dijkstra method according to the flowcharts of FIGS. The operation of the flowcharts of FIGS. 2 and 3 will be described in detail below. The omnidirectional search in FIGS. 2 and 3 is performed centering on the destination, and is continuously executed by utilizing the idle time of the CPU 4 until the ignition key (not shown) is turned off. In step S1 of FIG. 2, the final intersection is specified.
This final intersection exists, for example, as disclosed in Japanese Patent Laid-Open No. 62-86499, outside the circle of a predetermined radius centered on the destination from among the intersections around the destination, and the most destination. Select an intersection close to as the final intersection.

In step S2, the final intersection is set as the central intersection. Here, the central intersection refers to an intersection that is a search target. In step S3, 0 is set for the journey h at the final intersection.
And set a very large value + ∞ for the path h of all other intersections. Here, the path h refers to the distance from the final intersection to another intersection. In addition, all the flags provided for each intersection indicating 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 an adjacent intersection. In step S5, as shown in FIG. 4A, the distance h from the central intersection and the step S
The value obtained by adding the distance to the adjacent intersection selected in 4 is
It is determined whether or not the distance h is smaller than that 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 of FIG. 3, it is determined whether or not the current adjacent intersection exists in the central intersection candidate list A. Here, the central intersection candidate list A is a list in which the intersection numbers that can be the central intersections are described. If the determination is negative, the process proceeds to step S8, and the adjacent intersection is added to the central intersection candidate list A. In step S9, the current central intersection is set as the intersection A immediately before the adjacent intersection. Here, the immediately preceding intersection refers to an intersection that is the smallest of the adjacent intersections and that has a path h smaller than that of the adjacent intersection.

In step S10, it is determined whether or not the processes of steps S4 to S9 have been performed for all the adjacent intersections. If the determination is negative, the process returns to step S4, and if the determination is affirmative, the process proceeds to step S11. Step S
At 11, it is determined whether the central 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,
In the central intersection candidate list A, the intersection with the smallest distance h is set as a new central intersection.

In step S13, the central intersection newly selected from the central intersection candidate list A is deleted. In step S14, the flag of the central 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.

The operations of the flowcharts of FIGS. 2 and 3 described above can be summarized. Initial settings are made in steps S1 to S3, and the process h of the adjacent intersection is updated in steps S4 to S7. In steps S8 to S10, registration in the central intersection candidate list A and setting of the immediately preceding intersection of the adjacent intersections are performed. After performing the processes of steps S4 to S9 for all the intersections adjacent to the central intersection, the intersection having the smallest route h in the candidate list A of the central intersection is set as the central intersection in step S12. The processes of steps S4 to S10 are repeated until the ignition key is turned off or the central intersection candidate list becomes empty.

For example, before starting the processing of FIGS.
When the optimum route calculated by the PU 4 is the thick line portion in FIG. 4 (a), the processing of FIGS. 2 and 3 is performed for a predetermined time so that the range of the search area A indicated by the diagonal line in FIG. A route search is performed. As time goes on,
As shown in FIG. 4C, the area of the search area A becomes large.

On the other hand, the CPU 4 performs the route departure recovery process shown in FIGS. 5 to 7 at fixed intervals, for example, between the processes of FIGS. In this route departure return processing, it is determined whether or not the vehicle has left the route, and a route search from the position of the vehicle that left the route to the destination is performed. In step S101 of 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 and the like 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.
Similar to step S1 in FIG. 2, an intersection close to the current position of the vehicle is specified as a departure intersection. Step S103
Then, it is determined whether or not the flag of the departure intersection is "1". When this flag becomes "1", it indicates that the route search from the destination has already been completed for the current search target intersection (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 crossing selected in step S102 is obtained in the processes of FIGS. The route that follows the intersection A in order and reaches the target intersection is stored in the RAM 6 as a new optimum route, and the process ends. That is, even if the vehicle leaves the route, as shown in FIG. 8A, if the route search at the vehicle's current position (the arrow mark in the figure) has already been completed, a new route search is performed. The process ends without doing anything. 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.
By the processing from 5 onward, the search area B shown by the diagonal lines in the figure
The route is searched for in the range.

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

In step S110, the central intersection is set as the intersection B immediately before the adjacent intersection. Step S11
At 1, it is determined whether 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. 9B. Yes, in this case, the process proceeds to step S112 in FIG.

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

In step S115, it is determined whether or not the final intersection exists in the central intersection candidate list B. When the determination is negative, the process moves to step S116, the final intersection is registered in the central intersection candidate list B, and the step S in FIG.
Moving to 119.

On the other hand, if the determination is negative in step S111 of FIG. 5, 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 of FIG. It is determined whether or not the adjacent intersection exists in the central intersection candidate list B. When the determination is negative, the process proceeds to step S118, the adjacent intersection is additionally registered in the central intersection candidate list B, the straight line distance from the target intersection to the adjacent intersection is calculated, and the estimated distance h'is calculated.
To record as. In addition, the path g from the central intersection to the adjacent intersection is stored in the RAM 6 and the step S119 of FIG.
Move to.

Even when the determination in step S108 in FIG. 5 is negative, the process proceeds to step S119 in FIG. 7 to determine whether or not the processes in steps S107 to S118 have been performed for all the adjacent intersections, and the determination is affirmative. Then, the process proceeds to step S120. In step S120, the intersection having the minimum (g + h ') is selected from the candidate intersections B for central intersections as a new central intersection. Step S12
In 1, the intersection selected in S120 is deleted from the central intersection candidate list B. In step S122, it is determined whether the new central intersection is the final intersection, and if the determination is negative, the process returns to step S107 in FIG.

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

When the determination in step S122 is affirmative, the process proceeds to step S123, and 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, according to the route search result (search area A shown in FIG. 9C) from the contact intersection to the destination, the route from the contact intersection to the current location of the vehicle is processed by the processes of FIGS. The optimum route is obtained based on the search result (search area B shown in FIG. 9C).

In step S124, the route from the contact intersection to the final intersection is obtained by sequentially tracing the contact intersection A to the immediately preceding intersection A. In step S125, the route from the contact intersection to the departure intersection is obtained by sequentially tracing from the contact intersection to the immediately preceding intersection B. Step S
At 126, the optimum route from the starting intersection to the final intersection is obtained by combining the results of steps S124 and S125, and the result is stored in the RAM 6, and
Display on the display 9 and end the process.

As described above, the processes of the flowcharts of FIGS. 5 to 7 can be summarized. In step S101, it is determined whether or not the route is departed, and in steps S102 to S106, initial setting is performed. In steps S107 to S110, the path g of the adjacent intersection and the intersection just 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, and if the determination is affirmative, step S112.
The path g of the final intersection and the intersection just before the final intersection are updated through S116. On the other hand, step S110
If the determination is negative, the adjacent intersections are registered in the central intersection candidate list B and (g + h ') of the adjacent intersections is calculated in steps S117 and S118. For all intersections adjacent to the central intersection, step S10
After performing the processes of 7 to S118, the intersection having the smallest (g + h ') in the central intersection candidate list B is selected in step S120, and the processes of steps S107 to S121 are repeated. If the central intersection coincides with the final intersection, the contact intersection is set in step S123, and step S124 is set.
The optimum route is obtained through S126.

As described above, in the above-described embodiment, once the vehicle starts traveling, the CPU 4 makes use of the idle time to carry out an omnidirectional route search centered on the destination and the vehicle leaves the route. Whether or not it is regularly detected. When the vehicle departs from the route, it is determined whether the vehicle is located within the range in which the omnidirectional route search is performed. If the vehicle is located within the range, the omnidirectional search is performed. Since the optimum route is obtained according to the result, a new route search is not required. On the other hand, when the vehicle is not located within the omnidirectional route search range, the omnidirectional route search range is used as much as possible to perform the route search, which significantly reduces the time required for the route search. It

Although the omnidirectional route search is performed in the flowcharts of FIGS. 2 and 3, the directional search may be performed by the A ^* method or the like. In the flowcharts of FIGS. 5 to 7, the route search is performed from the vehicle position where the departure from the route is detected.
For example, when the vehicle is traveling on a road with few intersections, the future traveling position of the vehicle is predicted using the direction sensor 1 and the vehicle speed sensor 2, and the processing of the drawing is started from the predicted position. Good. In this way, the vehicle can be correctly guided even if the processing in FIGS. 5 to 7 takes time. When the vehicle departs from the route, a warning is displayed or a warning sound is generated to that effect, and when a new route is calculated, it is displayed in a color different from the conventional optimal route to alert the driver. You may urge me. In the above embodiment, the route that minimizes the vehicle travel distance to the destination is searched, but a route that minimizes the vehicle travel time to the destination may be searched.

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

[0034]

As described above in detail, according to the present invention, the second route searching means continuously searches for the optimum route from the destination to each intersection and the vehicle is the first route. When the route departs from the optimum route searched by the route search means, if the current position of the vehicle is within the search range by the second route search means, the optimum route is determined by the search result of the second route search means. Therefore, it is not necessary to search for a new route and the optimum route can be immediately obtained. Further, when the current position is not within the range searched by the second route searching means at the time of leaving the route, the optimum route is searched based on the search result of the second route searching means. Can be shortened to

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a vehicle route guide 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.

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

FIG. 5 is a flow chart showing a process of returning from a route by a CPU.

FIG. 6 is a flowchart following on from FIG.

FIG. 7 is a flowchart following FIG.

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

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

[Explanation of symbols]

 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

Claims (4)

[Claims] 1. A road map storage means for storing road map data including intersection information, a vehicle position detection means for detecting a current position of a vehicle, a destination setting means for setting a destination, and a road map data based on the road map data. And a first route searching means for searching an optimum route from the current position to the destination, and a display means for displaying the optimum route searched by the first route searching means. A second route searching unit that sequentially searches an optimum route from the ground to each intersection toward the surroundings from a destination, and a vehicle from the optimal route searched by the first route searching unit. Departure determination means for determining whether or not the vehicle has departed, and current location determination means for determining whether or not the current location of the vehicle that has left is within the range searched by the second route search means. If it is determined by the departure determination means that the vehicle has departed, and if it is determined that the current location determination means has not searched, the vehicle departs based on the search result by the second route searching means and the road map data. A route guide device for a vehicle, comprising: a third route search means for searching an optimum route from the current position to the destination. 2. The vehicle route guiding apparatus according to claim 1, wherein the third route searching means performs a search until reaching an intersection searched by the second route searching means. A vehicle route guidance device. 3. The vehicle route guiding apparatus according to claim 1, wherein the first route searching means, the second route searching means, and the third route searching means have the shortest vehicle travel time. A vehicle route guidance device characterized by searching a route. 4. The vehicle route guiding apparatus according to claim 1, wherein the first route searching means, the second route searching means, and the third route searching means have the shortest vehicle travel distance. A vehicle route guidance device characterized by searching a route.