JP3525032B2 - Route search device - 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 search device preferably implemented in a navigation device.

[0002]

2. Description of the Related Art A navigation device is equipped with a route search device. The route search device searches for a recommended route on which a vehicle should travel between a preset starting point and destination point based on predetermined search conditions. The so-called Dijkstra method is an example of this search method. For the route search in advance, the road of the road map is represented by approximating a plurality of road links connected via nodes, and the route cost is attached to each road link in advance. In the Dijkstra method, from a starting position to a destination position or vice versa, nodes on the road map are sequentially searched for nodes connected to the node via a single road link, and each node is searched. The route costs of the road links interposed therebetween are cumulatively added, and the route with the smallest sum of the route costs is determined as the recommended route.

The route cost is a weight indicating the priority of selection of each road link, and the larger the value, the more difficult it is to select. The route cost is determined, for example, in proportion to the time required to drive each road link, so the shorter the time required, the smaller the value. For this reason, when the route lengths of road links are equal, the route cost of a road link that constitutes a toll road such as an expressway is smaller than the route cost of a road link that constitutes a toll road such as an ordinary road. There are many.

Therefore, for example, when an entrance line and an exit line branching from the same point of the expressway are connected to a general road formed by connecting a plurality of road links, the entrance line and the exit line from the general road are connected. The sum of the route costs of the route that returns to the general road again through and may be smaller than the sum of the route costs of the route that travels only the general road without passing through the entrance line and the exit line. For this reason, when the recommended route of the road having the above-described structure is determined, the former route may be searched as the recommended route, although the latter route is preferable as the route to actually travel. by this,
The recommended route may be an inappropriate route that does not fit the actual driving.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a route search device capable of preventing a route search inappropriate for actual traveling in route search.

[0006]

According to the present invention, there is provided map data storage means for storing map data including road data composed of a plurality of road links and a plurality of nodes, and attribute data relating to road attributes, and map data storing means on the map data. Search for setting a departure position, a departure position setting means, a destination position setting means for setting a destination position on the map data, and map data from the map data storage means, and searching for a recommended route connecting the departure position and the destination position. In the route search device including means, the search means, when the node is an entrance or exit of a toll road, attribute change determination means for determining that the attribute of the road changes, and all road links connected to the node. When the road link behind in the direction of travel is a toll road and at least one of all road links is a free road, An attribute combination determining means determines that the sexual combination is a combination of predetermined, when the attribute of the road is determined to be changed by the attribute change determining means,
Predetermined weighting is applied to the route, and
A route search device comprising: an adjustment unit that performs predetermined weighting on the route when the attribute combination determination unit determines that the combination of road attributes is a predetermined combination.

According to the present invention, the route search device searches for a recommended route connecting the starting position and the destination position, as described above. For this purpose, the route search device first sets the starting position and the destination position by the starting position setting means and the destination position setting means as described above, and then searches the route from the starting position to the destination position by the searching means. To do. At this time,
For example, the search means obtains the sum of the route costs added to the road links forming the route for each route. In the conventional route search device, the sum of the route costs is compared at this point and the route with the smallest sum of the route costs is determined as the recommended route. Therefore, as described above, the short distance of about 1 km is applied to the toll road. In some cases, an improper route such as passing through was decided as the recommended route.

After calculating the sum of the route costs, the route search device of the present invention determines, for each route, whether or not the attribute of the road changes at the node in the route by the attribute change determination means. The road attribute represents the type of road represented by the road link, and the type includes either a toll road or a free road. The attribute change determining means determines that the attribute of the road changes when the node is an entrance or an exit of the toll road. If nodes corresponding to the entrance and exit of the toll road are on the route, the route changes from the toll road to the toll road or from the toll road to the toll road when the node passes through the node. Therefore, the road attribute of the route changes. Therefore, it is possible to determine whether or not the attribute of the road has changed by the above processing operation. For this determination, for example, it may be determined whether or not the node is an entrance and an exit of a toll road by examining data representing what point the node corresponds to on the road map. Such data is often stored as so-called node data in the navigation device in association with the map data for route guidance. Therefore, this determination process can be easily performed using this data. When the road attribute changes as a result of such a determination, the adjusting means weights the sum of the route costs by adding a predetermined value to increase the sum of the route costs. As a result, the sum of the route costs increases as the attribute of the road changes in the route. The route search device also includes attribute combination determination means in addition to the attribute change determination means. The route search device calculates the sum of the route costs, and then, for each route, by the attribute combination determination means, for each node in the route, the combination of the attributes of the roads of all the road links connected to the node is determined as described above. It is determined whether the combination is a predetermined combination. In the attribute combination determination means, among all the road links connected to the node, the road link behind in the traveling direction is a toll road,
When at least one of all road links is a free road, it is determined that the combination is a predetermined combination.
Such a node is an exit of the toll road, and the attribute combination judging means judges whether the route passes through the exit of the toll road. In this way, when it is determined that the combination of the road attributes of the road link is the predetermined combination, the adjusting unit weights the sum of the route costs of the routes by a predetermined value, for example. Do and increase the sum of the route costs. As a result, the sum of route costs increases as a route passes through a node between two road links having different road attributes regardless of whether or not the road attribute changes in the route. Thus, based on the combination of road attributes and road attributes,
After adjusting the sum of the route costs, compare the sum of the route costs,
The route with the smallest sum of route costs is determined as the recommended route.

For example, it is assumed that there is a reference road that is a toll road and a detour that is connected to the reference road and extends substantially in parallel and that is a toll road. When the lengths of the road links are equal, the attribute of the road of the reference road, that is, the route cost of the road link of the free road is larger than the attribute of the road of the detour, that is, the route cost of the road link of the toll road. This road map is
It corresponds to the road map of FIG. When both ends of the reference road are set as the starting position and the destination position on this road map, the searching means causes the first route to return to the reference road from the reference road via the detour and the first route to pass only the reference road. Either of the two routes should be obtained as the recommended route.

At this time, regardless of the length of the section in which the reference road and the detour extend in parallel, the sum of the route costs of the first route before weighting by the adjusting means is the second route before weighting by the adjusting means. Less than the sum of the route costs. At this time, the attribute of the first route changes at the time when it passes through the nodes of the reference road and the detour, so that the sum of the route costs is increased by the adjusting means. Further, since the road attribute does not change for the second route, the sum of the route costs is kept at the value obtained by the adding means.

When the difference in the sum of the route costs of the routes before weighting by the adjusting means is less than the predetermined value,
That is, when the length of the section is shorter than the predetermined route length, the sum of the route costs of the first route becomes larger than the sum of the route costs of the second route after the adjustment. Therefore, the second route can be determined as the recommended route. At this time,
The road attributes do not change within the recommended route. That is, the route through which the vehicle passes the single road is determined as the recommended route. Further, when the difference is equal to or more than the predetermined value, that is, when the length of the section is equal to or more than the predetermined route length, the sum of the route costs of the first route is equal to the route cost of the second route even after the adjustment. It is kept smaller than the sum.
Therefore, the first route can be determined as the recommended route. When the entrance and exit to the toll road are connected to the same toll road, the search means can search for a route from the toll road to the toll road through the entrance and then to the toll road back to the toll road. is there. It is preferable to avoid such a route because it is an inappropriate route for the vehicle to actually travel. When the change in the attribute of the road is determined as described above, it is possible to reliably prevent such a route from being fixed as the recommended route.

As described above, in the route search device of the present invention,
By the attribute change determination means and the adjusting means, in response to the presence or absence of a change in the attributes of the roads in the route, weighting is performed to adjust the sum of the route costs, and the sum of the adjusted route costs is compared, The route with the smallest sum of the route costs is determined as the recommended route. As a result, as described above, it is determined whether or not to avoid such a route according to the length of the section, instead of avoiding all the routes whose road attributes change in the middle of the route. Therefore, it is possible to prevent the route that is not suitable for the actual traveling of the vehicle, such as returning from the reference route to the reference road via a bypass having a short route, to be determined as the recommended route. Therefore, reasonable search results can be provided to the occupants of the vehicle. In addition, since this route avoidance method only adds a predetermined value in response to the presence or absence of an attribute change in the route, this function can be easily added to the conventional route search device. Therefore, it is easy to realize.

The predetermined value is, for example, an adjustment route cost determined corresponding to a combination of the attributes of each road of two road links connected by a node. The predetermined value may be set only by a combination of two roads regardless of the traveling direction when the vehicle travels on the route. Further, the predetermined value depends on the traveling direction when the road attribute changes from the first road attribute to the second road attribute when the vehicle passes through the above-mentioned node, and Different values may be set when the attribute changes from the attribute of the second road to the attribute of the first road.
Further, the predetermined value is a value that should be set according to the predetermined distance, and this value may be different depending on the type of combination of road attributes. That is, when the combination of road attributes is different, the predetermined distance may be changed. These conditions can be changed easily because only specific numerical values of predetermined values are changed. Therefore, even when these conditions are increased, it is possible to reduce the load on the circuit that performs the arithmetic processing for route search.

Further, for example, a first road which is a toll road is curved at a first node, a second road which is a free road is connected from the first node, and a straight road is formed by the first road and the second road. Further, it is assumed that there is a road map in which the first road is connected to the detour of the toll road at the second node ahead of the first node in the traveling direction of the vehicle, and the detour is connected to the second road. The relationship between the route cost of the road link of the first road and the route cost of the road link of the second road, that is, the relationship between the route cost of the toll road and the route cost of the free road is the same as described above. This road map corresponds to the road map in FIG.

On this road map, a point behind the first node on the first road in the traveling direction is set as a starting position, and a point ahead of the first node on the second road in the traveling direction is set as a destination position. When the search is performed, the searching means includes a first route from the first road to the second road via the second node and the detour,
The second from the first road to the second road via the first node
Make one of the routes the recommended route. At this time, since the first route has a longer traveling distance on the first road than the second route, the sum of the route costs of the first route is irrespective of the route length of the section between the first node and the second node. , Less than the sum of the route costs of the second route.

The first node is connected to the first road and the second road, and the second node is connected to the first road and the detour. The combination of road attributes of all road links connected to the two nodes is determined to be a predetermined combination.
At this time, since the first route passes through the first node and the second node, the sum of the route costs is increased twice by the adjusting means. Further, since the second route passes only the first node, the sum of route costs is increased only once. Therefore, the sum of the route costs of the routes is increased as the number of times the node passes through which the combination of the road attributes of all the road links becomes a predetermined combination.

When the difference in the sum of the route costs of the respective routes adjusted by the adjusting means is less than the predetermined value,
That is, when the length of the section is shorter than the predetermined route length, the sum of the route costs of the first route becomes larger than the sum of the route costs of the second route. Therefore, the second route can be determined as the recommended route. When the difference is equal to or more than the predetermined value, that is, when the length of the section is equal to or more than the predetermined route length, the sum of the route costs of the first route is smaller than the sum of the route costs of the second route. To be kept. Therefore, the first route can be determined as the recommended route.

In other words, when the two exits of the toll road are connected to the same toll road and the toll road between the two exits extends substantially parallel to the toll road, the search means is Of the two exits, a route that turns into a toll road may be searched via an exit in the forward direction. It is preferable to avoid such a route because it is an inappropriate route for the vehicle to actually travel. When determining the change of the attribute of the road by the above-described method, it is possible to reliably prevent the determination of such a route as the recommended route.

As described above, in the route searching device, the attribute combination determining means and the adjusting means adjust the number of passages through the nodes in which the combination of the road attributes of all road links becomes a predetermined combination. The sum of the route costs is adjusted, the adjusted sums of the route costs are compared, and the route having the smallest sum of the route costs is determined as the recommended route. Therefore, instead of avoiding all the routes passing through the above-mentioned nodes in the middle of the route, whether to avoid such a route is determined according to the length of the section.

As a result, when two roads having different road attributes are connected as described above and the route length of the section between the first node and the second node is short, the second node and the detour are connected. It is possible to prevent the route that is not suitable for the vehicle actually traveling, such as the route, to be determined as the recommended route. Therefore, reasonable search results can be provided to the occupants of the vehicle. Further, since the method of avoiding the route only adds a predetermined value according to the number of times, this function can be easily added to the conventional route search device. Therefore, it is easy to realize.

As described above, this predetermined value is a value that should be set according to the route length of the section, and this value may be different depending on the type of combination of road attributes. . That is, when the combination of road attributes is different, the predetermined distance may be changed. These conditions can be changed easily because only specific numerical values of predetermined values are changed. Therefore, even when these conditions are increased, it is possible to reduce the load on the circuit that performs the arithmetic processing for route search.

The present invention is provided with both attribute change determining means and attribute combination determining means, and is suitable for running on a road as shown in FIGS. 5 and 6 in both cases. The route can be established as the recommended route.

Further, according to the present invention, map data storing means for storing map data including road data consisting of a plurality of road links and a plurality of nodes and attribute data regarding road attributes, and a starting position on the map data are set. A route including a departure position setting unit, a destination position setting unit that sets a destination position on the map data, and a search unit that reads the map data from the map data storage unit and searches for a recommended route connecting the departure position and the destination position. In the search device, the search means is an attribute change determination means for determining that the attribute of the road is changed when one of the two continuous road links is a toll road and the other is a free road. , Of all the road links connected to the node, the road link behind in the traveling direction is a toll road, and When Kutomo one is a free road,
Attribute combination determination means for determining that the combination of road attributes is a predetermined combination, and when the attribute change determination means determines that the attributes of the road will change, the route is weighted in advance, and A route search device comprising: an adjustment unit that performs predetermined weighting on the route when the attribute combination determination unit determines that the combination of road attributes is a predetermined combination.

In the present invention according to claim 2, the attribute change determining means determines the attribute of the road when one of the two continuous road links is a toll road and the other is a toll road. Is different from the present invention described in claim 1, but is otherwise the same. In this way, the combination of the road attributes of the two road links is used to determine whether or not the road attributes have changed. This is equivalent to determining whether or not the node is the entrance and exit of the toll road by this combination. This makes it possible to make the determination without further adding the data for determining whether the node is the entrance or exit of the toll road to the map data of the related art. Further, in the above-described method, it is only necessary to determine whether or not the road attributes of the two road links are different, and therefore the processing is extremely easy. Therefore, the amount of processing for determining whether or not there is a change in the attribute of the road is small, so that the burden on the circuit components for the calculation processing of the route search can be reduced. Even with such a configuration, it is possible to achieve the same effect by weighting the routes as in the first aspect.

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

In the present invention, the map data storage means has a route cost preset based on the time required for the vehicle to travel on the actual road, the length of the road represented by the road link, and the width of the road. Information is stored, and the searching means searches for a recommended route based on the route cost.

According to the present invention, the searching means searches for the recommended route based on the route cost. As a result, for example, as described in claims 1 and 2, the recommended route can be determined by the size of the sum of the route costs.
Therefore, the search for the recommended route becomes easy. Moreover, since weighting is performed in addition to the route cost as described above, it is possible to prevent an inappropriate route from being a recommended route, as described above.

Further, the above route searching apparatus becomes more difficult to be selected as the map data representing a road approximated by connecting a plurality of road links and the value indicating the priority of selection of each road link are larger, and A combination route cost that is set in advance for each road link according to a combination of a road link and a road link connected to the road link and has a larger value as the road attributes of both road links differ is stored. Map data storage means, start position setting means for reading the map data stored in the map data storage means and setting a start position on the map data at which the vehicle should start traveling, and a map stored in the map data storage means. A destination position setting means for reading data and setting a destination position on the map data that the vehicle should reach, a map data storage means, a departure position setting means, and a destination position setting means. In response to the force, the map data is read from the map data storage means, and the route from the start position set by the start position setting means to the destination position set by the destination position setting means is selected from the road links in the map data. In response to the output of the searching means for searching, the map data storing means, and the searching means, for each route searched by the searching means, the route cost for the combination of all the road links constituting the route, which is the route The combination route cost corresponding to the combination of two road links that are sequentially adjacent to each other in the traveling direction is read from the map data storage means, and all the combination route costs are added to obtain the sum. The configuration may include an adding unit and a determining unit that responds to the outputs of the searching unit and the adding unit and that determines the route with the smallest sum as the recommended route.

This route search device differs from the above-mentioned route search device in the route cost stored in the map data storage device, the operation of the addition means, the attribute change determination means and the adjustment means, and the others. equal. In this route search device, as described above, the adding means is the route cost for combination corresponding to each road link forming the route, and the road link and the traveling direction of the road link are sequentially forward or backward. All the combination route costs corresponding to the combination with the adjacent road links are added to obtain the sum.

This combination route cost is preset as described above. That is, this combination route cost is equal to the route cost stored in the map data storage means of the route search device when the road attributes of both road links are equal. When the road attributes of the both road links are different, it is the sum of the route cost and the predetermined value added by the adjusting means of the route search device. Therefore, the sum of the combination route costs by the adding means is equal to the sum of the route costs adjusted by the adjusting means by the above-mentioned route searching device. If the deciding means is made to decide the recommended route using the sum of the combined route costs, the recommended route is decided in the same manner as described above. As a result, the route search device according to the present invention can achieve the same effect as the route search device described above. Therefore, the route search device can simplify the structure and the processing procedure.

The combination route cost may be determined by adding the above-mentioned predetermined value to the above-mentioned route cost. As a result, the same effect as described above can be achieved. Therefore, the structure and processing procedure of the route search device can be simplified.

[0052]

1 is a block diagram showing a schematic electrical configuration of a navigation device 1 including a route search device 9 according to a first embodiment of the present invention. The navigation device 1 is mounted in, for example, a vehicle, and searches for and guides a route along which the vehicle should travel. Navigation device 1
Includes a map data storage device 3, a vehicle position search device 44, an input device 5, a search processing device 6, a route guidance device 7, and an output device 8. A route search device 9 is composed of the map data storage device 3 and the search processing device 6.

The map data storage device 3 stores map data representing a road map. In the road map, the roads of the actual road map are approximated by connecting the road links by so-called polygonal line approximation, and the points on the road map are represented by nodes. The road attribute and the route cost of each road link are stored together in this road data. Details of the road map and the map data will be described later. The vehicle position search device 4 is
Search for the current vehicle position of the vehicle. The input device 5 is operated by a vehicle occupant. The occupant operates the input device 5 to instruct start / end of the operations of the search processing device 6 and the route guidance device 7, specify a departure point at which the vehicle should start traveling, and specify a destination point at which the vehicle should reach. Designate.

The search processing device 6 includes a starting position setting section 11,
Target position setting unit 12, search unit 13, calculation unit 14, attribute change determination unit 15, adjustment units 16 and 18, combination determination unit 1
7, a confirmation unit 19 and a search result storage unit 20 are included.

The departure position setting unit 11 sets the departure position where the vehicle should start traveling on the road map based on the map data and the departure point input from the input device 5. The departure point may be the vehicle position searched by the vehicle position search device 4. The destination position setting unit 12 calculates the destination based on the map data and the destination input from the input device 5.
Set the destination position that the vehicle should reach on the road map.

The search unit 13 responds to the outputs of the departure and destination position setting units 11 and 12 and the map data storage device 3, and searches for a plurality of routes from the departure position to the destination position that should be recommended routes. . In general, a starting point link that is the starting point of the search is set, all the connecting nodes that are connected to the connecting node at the end of the starting point link via the road link are searched, and this road link is linked to the next starting point link. And This series of search processes is repeated until the road link passing through the starting position or the destination position is the first starting point link and the next starting point link is the road link passing through the destination position or the starting position. Every time the search unit 13 searches for a road link, the calculation unit 14 obtains the accumulated cost of the route having the first starting point link and the road link at both ends. The cumulative cost of the route is
It is the sum of the route costs of all road links that make up the route.

Each time the search unit 13 searches for a road link, the attribute change judgment unit 15 judges whether or not the road attribute has changed at the connection point where the road link and the origin link are connected. In response to the determination result of the attribute change determination unit 15, the adjustment unit 16 increases the accumulated cost of the route passing through the connection point when the attribute of the road changes, and when it does not change, the accumulated cost of the route remains unchanged. Adjust cumulative costs to keep.

Further, the combination determination unit 17 is composed of the search unit 13
Each time the vehicle searches for a road link, whether the combination of road attributes of all road links connected to the connection point where the road link and the starting point link are connected is a predetermined combination of road attributes. To determine. The adjusting unit 18 responds to the determination result of the combination determining unit 17, increases the accumulated cost of the route passing through the connection point when the combination of road attributes is a predetermined combination, and otherwise, the route. The accumulated cost is adjusted so as to keep the accumulated cost of.

The deciding unit 19 compares the accumulated costs of the respective routes adjusted by the adjusting units 16 and 18, and the searching unit 13
The route with the smallest cumulative cost is selected from the plurality of routes searched by. If the road link at the opposite end to the first starting point link at both ends of this route is not the road link passing through the destination position or the departure position, the road link is set as the next road link, and the searching unit 13 to the adjusting unit 18 Repeat the process up to. If the road link is a road link passing through the destination position or the departure position, the route is decided as the recommended route. The processing of the search unit 13, the calculation unit 14, and the determination unit 19 can be realized by, for example, the so-called Dijkstra method.

The recommended route determined by such a procedure is
It is the route with the smallest cumulative cost, and such a route is one of the multiple routes from the starting position to the destination position.
For example, it is a route that requires the shortest time for a vehicle to travel along a route to reach a destination position from a starting position, or a route that has the shortest route length. The recommended route determined by the determination unit 19 is stored in the search result storage unit 17.

The route guidance device 7 stores the contents stored in the search result storage unit 17 of the search processing device 6, the map data read from the map data storage device 3, and the vehicle position searched by the vehicle position search device 4. Guide information is created based on and. The guidance information includes, for example, the current position of the vehicle, the presence / absence of an intersection ahead of the vehicle in the traveling direction, and data for indicating the direction in which the vehicle should travel in the future. The guidance information is visually displayed or voiced by the output device 8 and provided to the occupant of the vehicle. In addition, the output device 8 is provided with the own vehicle position searched by the own vehicle position search device 4 and the recommended route stored in the search result storage unit 17 of the search processing device 6, and determines the own vehicle position and the recommended route. Is overlaid on the road map and displayed.

FIG. 2 is a block diagram showing a specific electrical structure of the navigation device 1. Specifically, the navigation device 1 includes a regulator 21, a power detection circuit 22, a central processing circuit 23, memories 24 and 25, an input device 5, a storage medium 26, a data reading device 27, a data conversion device 28, and sensors 29 to 31. , Interface 32,
GPS device 33, display device 34, graphic memory 3
5, a graphic controller 36, a display controller 37, and a system bus 39. Central processing unit 2
3, memories 24 and 25, input device 5, data conversion device 2
8, the graphic controller 36, the display controller 37, and the interface 32 include a system bus 39.
And signals can be exchanged between them.

Each part 21 to 37 of the navigation device 1
Is supplied with power from the vehicle power supply 41 via the power switch 42 and the regulator 21. Power supply 41
Is a power supply for supplying electric power to the lighting device 43 of the vehicle and the electric parts of the vehicle, for example, the power switch 42.
And an illumination switch 44, and is connected to the illumination device 43 of the vehicle. When the lighting switch 44 and the power switch 42 are both electrically connected, power is supplied to the lighting device 43.
The power switch 42 is realized by, for example, an ignition switch. The regulator 21 stabilizes the voltage of the electric power supplied from the power supply 41. Power detection circuit 22
Detects whether or not electric power is supplied to the conductor 45 between the power switch 42 and the regulator 21 to detect the power supply 41 of the vehicle and the components 21 to 3 of the navigation device 1.
It is detected that power supply to 7 has started. The central processing circuit 23 starts its operation from the time when the power detection circuit 22 detects the start of power supply.

The central processing circuit 23 reads the operation program stored in the memories 24 and 25 and operates according to the operation program. The memory 24 stores an operation program and invariant data necessary for executing the program. The memory 25 is a writable memory and stores variable data necessary for executing a program. Further, the search result storage unit 20 is provided in the memory 25. The memory 24 is realized by, for example, a read only memory, and the memory 25 is realized by a random access memory. The central processing circuit 23 and the memories 24 and 25 operate as the search processing device 6 and the route guidance device 7 by changing the operation program to be executed. Further, as will be described later, it operates as a component for arithmetic processing of the vehicle position search device 4. The respective units 11 to 19 and the route guidance device 7 in the search processing device 6 are virtual circuits realized by the arithmetic processing of the central processing circuit 23. Each of these parts 11 to 1
9 and the route guidance device 7 may be individually prepared as existing circuits.

The map data storage device 3 includes a recording medium 26, a data reading device 27 and a data converting device 28.
The storage medium 26 stores map data, for example, electrically, magnetically or optically, and is attached to the data reader 27. The data reader 27 operates in response to a control signal provided from the central processing circuit 23 via the data converter 28 to electrically, magnetically, or electrically output a desired portion of the map data from the storage medium 26. Read optically. The data conversion device 28 converts the map data read by the data reading device 27 into the search processing device 6 and the route guidance device 7.
And output to the output device 8 after converting into a form that can be processed. The map data output from the data conversion device 28 is stored in the memory 25. The map data is preferably stored in a storage medium that can be attached to and detached from the data reader 27 and can be exchanged. For this reason, the storage medium 26 is realized by, for example, a CD-ROM.

The vehicle position searching device 4 includes a direction sensor 29,
Angular velocity sensor 30, distance sensor 31 Interface 3
2, GPS device 33, central processing circuit 23 and memory 2
Including 4,25. The vehicle position is represented by latitude and longitude and altitude, for example.

The azimuth sensor 29 detects the traveling direction of the vehicle. The angular velocity sensor 30 detects an angular velocity when the traveling direction of the vehicle is angularly displaced. The distance sensor 31 detects the traveling distance of the vehicle. The detection results of the sensors 29 to 31 are given to the central processing circuit 23 via the interface 32. The central processing circuit 23 reads the operation program for the own vehicle position search operation from the memory 24, and the sensors 29 to 3
Based on the detection result of 1, the own vehicle position is calculated as a position relative to the reference position. Specifically, for example, first, the presence or absence of angular displacement and the amount of angular displacement in the traveling direction of the vehicle are obtained from the angular velocity detected by the angular velocity sensor. Each time the vehicle is angularly displaced, the traveling distance measured by the distance sensor 31 while the vehicle travels while maintaining a certain traveling direction before the angular displacement is corrected according to the traveling direction detected by the azimuth sensor 29 and accumulated. The distance of the vehicle from the predetermined reference point is calculated by the addition, and the position separated from the reference position by the distance is set as the own vehicle position. GPS (Grobal Positioning System) device 3
3 performs triangulation using signals from a plurality of positioning satellites that orbit the earth, and detects the own vehicle position, the traveling direction of the vehicle, and the current time. The detection result of the GPS device 33 is given to the central processing circuit 23 via the interface 32.

The input device 5 is realized by, for example, a remote controller equipped with a keyboard and an input device in which a display device and a touch panel are combined.

The output device 8 includes a display device 34, a graphic memory 35, a graphic controller 36,
And a display controller 37. The display device 34 includes a two-dimensional display screen capable of displaying an image, and is realized by, for example, a liquid crystal display device and a cathode ray tube. The graphic memory 35 stores drawing data representing various images. The graphic controller 36 uses the central processing circuit 2
Controlled by 3, the drawing data is read from the graphic memory 35 and image data representing an image to be drawn on the display screen of the display device 34 is created. This image data is also stored in the graphic memory 35. The display controller 37 is controlled by the central processing circuit 23 and supplies the image data created by the graphic controller 36 to the display device 34 to display the image on the display screen. Further, the output device 5 may include a speaker for acoustic display.

FIG. 3 is a schematic diagram of a road map for explaining map data. The road map expresses an actual road as a polygonal line approximation by connecting a plurality of road links, and points on the road map are expressed by nodes. A road link is a line segment that constitutes a polygonal line that is an approximation of an actual road and that has inflection points or intersections of the actual road as its ends. A node is a point corresponding to an inflection point of the polygonal line and an intersection of the polygonal line, and represents a point on the road map. The points represented by the nodes include intersections and inflection points of roads, that is, points at both ends of road links.
The node and the road link are alternately and sequentially connected to form the polygonal line.

In the following description, nodes corresponding to both ends of the link will be referred to as connecting nodes, and nodes corresponding to points in the middle of the link and points away from the link will be referred to as interpolation nodes. A predetermined number is attached to the road link and the connection node. Hereinafter, the connecting node with the number Nn is denoted by the same reference numeral as that number, and the reference numeral Lab is attached to the road link which allows the vehicle to travel from the connecting node Na to the connecting node Nb with the connecting nodes Na and Nb at both ends. Attach.
n, a, and b are natural numbers of 1 or more and less than N, and N is an arbitrary natural number. For example, the road map of FIG. 3 has five connecting nodes N0 to N4 and eight links L01 to L04, L.
10-L40, each link L01-L04, L10
To connection node N0 and connection node N1 through L40
N4 and N4 are individually connected.

The map data will be described below. The map data includes road link data, node data, and searched road data.

The road link data includes, for example, a link length, a road direction, a road attribute, a route cost, and a traffic regulation. The road azimuth is a value indicating the direction in which the road link extends with reference to a predetermined reference azimuth, and the reference azimuth is, for example, 0 degrees north latitude. The route cost is the road link L
It is a weight indicating the ease of selection when selecting na as a route. The specific value of the route cost is determined in relation to the time required for the vehicle to travel on the actual road.
For example, the numerical value increases in proportion to the required time. Further, the specific numerical value of the route cost may be determined in relation to the length of the road represented by the road link and the width of the road, and the numerical value increases in proportion to the length and the width. The node data includes a connection node and an interpolation node, and includes attributes such as latitude and longitude of a point represented by each node, a place name, an intersection, and the presence or absence of a building. Specifically, the search road data represents a map formed by connecting a road branch point such as an intersection and a road attribute change point by a link, and is used for route search.

Generally, even a road link having connection nodes Na and nb at both ends is connected from a connection node Nb to a road link Lab in which a vehicle can travel from the connection node Na to the connection node Nb. The data related to the road link, for example, the route cost is different from the road link Lba in which the vehicle can travel toward the node Na. The road link data, the node data, and the searched road data are stored as, for example, tabular data. Corresponding tables of the road link data and the node data are respectively allocated to the searched road data, and the same number of the road link is attached to the information regarding the same road link and node. Therefore, the searched road data, the road link data, and the node data are associated with each other.

FIG. 4 is a schematic diagram showing a specific structure of the searched road data. It is assumed that the searched road data in FIG. 4 represents the road map shown in FIG. Search road data includes
As shown in FIG. 4A, the 0th to Mth node information are included. This node information is prepared in the same number as the number M + 1 of all connection nodes included in the road map. Each node information individually corresponds to each connection node. The nth node information of a certain connection node Nn includes the number of connection links, connection node information, and connection link information, as shown in FIG. 4B.

The connection link number information indicates the number x of road links connected to the connection node Nn. The number x of the road links is equal to the number of connection nodes na connected to the connection node Nn via a single road link. The connection node information represents all the numbers of the connection nodes Na connected to the connection node Nn via a single road link. In the drawings, the number a is described as “na”.

The connection link information is information related to the connection node Nn and the road link Lna having the connection nodes Na at both ends, and each connection node Na has a number stored in the connection node information. Be prepared in relation to. In the drawing, the road link Lab is described as “na → nb”. The connection node information and the connection link information are shown in FIG.
As shown in (3), it is stored in a table format, for example. For example, in the node information n of the connection node Nn, the connection link information related to the connection node Na is information related to the road link Lna. The same number of connection link information items as the connection node number x are prepared.

The connection link information of each road link Lna is
Includes traffic restrictions, road type, road width, and link length. The traffic regulation indicates, for example, the presence or absence of one-way traffic and the speed limit. The road type is a so-called road attribute and represents, for example, whether the road link Lna is an expressway or an ordinary road, a national road, a prefectural road, or a narrow street, or a tunnel. . Road width is road link Ln
It represents the actual width of the road represented by a. The link length represents the actual length of the road represented by the road link Lna.

The inter-link information is information relating to the route Xbna consisting of two road links Lbn and Lna connected via the connection node Nn, and as shown in FIG. 4 (4), for each route Xbna. Be prepared for. Therefore, the same number of pieces of inter-link information as the product {x × (x−1)} of the number x of connection nodes and the number x−1 that is one less than the number x are prepared.
In the drawing, the route Xbna is described as “nb → nn → na”. The link information related to a certain route Xbna includes:
Includes traffic restrictions. The traffic regulation of the route Xbna is, for example, a summary of the traffic regulation of the connection node Nn and the road links Lbn and Lna.

The route search operation performed by the route search device 9 will be described below.

First, a route search operation for searching for a recommended route on a road map having the structure shown in FIG. 5 will be briefly described. The road map of FIG. 5 includes connection nodes N0 to N7 and road links L01, L12, L13, L27, L23, L.
36 and. The road links L01 and L13 are connected via the connection node N1, the road links L13 and L36 are connected via the connection node N3, and the road links L01 and L13 are connected.
13 and L36 form a straight road. The road link L, which is the entrance line of the toll road, is connected to the connection node N1 on this straight road.
12 is connected, and the road link L23, which is the exit line of the toll road, is connected to the connection node N3 on the straight road. The road links L12 and L23 form a detour that bypasses a part of the straight road. The road links L12 and L23 are connected to the road link L27, which is the main line of the toll road, via the connection node N2. In the drawing, free roads are indicated by thin solid lines and toll roads are indicated by thick solid lines.

The route cost of the road links L12 and L23 is 1, and the route cost of the road link L13 is 5. Further, the path length of the detour between the connection nodes N1 and N3 is shorter than the general path length of the entire recommended path, and is, for example, about 1 km. In the example of FIG. 5, the departure position is a point Ps on the road link L01, and the destination position is a point Pg on the road link L36. In FIG. 5, the appropriate route suitable for the actual traveling of the vehicle is shown by hatching. In the example of FIG. 5, it is preferable that the vehicle goes straight on the free road without passing through the toll road, so the appropriate route is a linear route that sequentially passes through the road links L01, L13, and L36.

In the route search operation, the search unit 13 first sets the first starting point link that is the starting point of the route search and the ending point link that is the ending point of the route search. In the example of FIG. 5, the first starting point link is the road link L01 and the ending point link is the road link L36. Then, the search unit 13 searches for a route on the road map that has the first start point link and the end point link as both ends. This route is the road link L12,
There are two types, a first route that passes through L23 in order and a second route that passes through the road link L13. The first route is a route from the toll road to the toll road again via a detour that extends substantially parallel to the toll road. The second route is a route that passes only on toll roads.

The calculation unit 14 obtains the cumulative costs of these two routes. The cumulative cost of the first route is the road link L
Since it is the sum of the route costs of 12 and L23,
It turns out that Since the second route is composed of only the road link L13, its accumulated cost is equal to the route cost of the road link L13, and it can be seen from Expression (2) that the cost is 5. Cumulative cost of the first route = 1 + 1 = 2 (1) Cumulative cost of the second route = 5 (2)

In the conventional route searching apparatus, the cumulative cost of the first route and the cumulative cost of the second route are compared at this point, and the route with the smallest cumulative cost is determined as the recommended route. Therefore, the first route is determined as the recommended route.
As a result, when the vehicle actually travels, 1 km
Although it is preferable that the route not pass through a detour having a short route length, it is decided that the first route is the recommended route. The first route also does not match the appropriate route.

The route search device 9 of the present embodiment further adds an adjustment cost in response to the presence / absence of a change in the attribute of the road to the above-mentioned accumulated cost so that the route having the change in the attribute of the road is accumulated. Increase costs. The adjustment cost is
A route that returns to the original route via the accumulated cost of a route consisting of road links having a certain road attribute and a route having a road attribute of a predetermined length that differs from the certain road attribute in the middle of the route It is preferable to set it to a value larger than the difference with the cumulative cost of. For example, if the route cost of the road link is 1 to 5, the adjustment cost is set to 10 to 20. In the example of FIG. 5, the adjustment cost is 10.

Specifically, first, the attribute change determination unit 15
However, for each of the first and second routes, it is determined whether or not the road attribute of the road link that constitutes the route changes, with the connection node on each route as a boundary. In the example of FIG. 5, on the first route, the connection node N1 changes the road attribute from a free road to a toll road. At the connection node N2, the road attribute remains a toll road. At the connection node N3, the road attribute changes from a toll road to a free road. In the second route, the connection nodes N1 and N3 do not change the road attribute, which is a free road.

Then, when the attribute change determination unit 15 determines that the attribute of the road has changed for each connection node, the adjustment unit 16 accumulates a predetermined adjustment cost for the route passing through the connection node. Add to the cost. In the example of FIG. 5, since the road attribute changes at the connection nodes N1 and N3 in the first route, the adjustment cost is added twice. Therefore, the accumulated cost of the first route is 22. The adjustment cost is not added to the second route because the road attribute does not change at any connection node, and the accumulated cost of the second route remains 5. Therefore, when the cumulative cost of the first route and the cumulative cost of the second route are compared at this time point, the cumulative cost of the second route becomes larger than the cumulative cost of the first route, so that the determination unit 19 determines that the appropriate route is appropriate. The matching second route can be determined as the recommended route.

Next, the route searching operation for searching for the recommended route on the road map having the structure shown in FIGS. 6 and 7 will be briefly described. The road maps of FIGS. 6 and 7 differ from the road map of FIG. 5 in the road attributes and route costs of each road link, and are otherwise the same, so description of the same parts will be omitted. Of all road links in this road map, road link L
01 and L12 are toll roads, and road links L13 and L13
23, L27 and L36 are free roads. Road link L
The route cost of 01 and L12 is 1, and the road link L2
It is assumed that the route cost of 3 is 2 and the route cost of the road link L13 is 5.

First, the recommended route on this road map is shown in FIG.
Consider the case where the route is searched by the route search operation described in the example. In the example of FIG. 6, the departure point is the point Ps on the connection node N0, and the destination point is the point Pg on the road link L36. Therefore, the first starting point link is the road link having the connection node N0 as one end, and the ending point link is the road link L.
36. Since it is preferable that the vehicle goes straight through the intersection as much as possible, the appropriate route in the example of FIG. 6 is the road link L0.
1, L13, L36.

The search unit 13 uses the road links L01 and L1.
2, the first route passing through L23, and the road link L01,
A second route that sequentially passes through L13 is searched. The first route is
It is a route from a straight road to a straight road via a detour. The second route is shorter than the first route through the toll road, but is always a straight route. In the example of FIG. 6, the adjustment cost is 3.

The attribute of the first route changes from the toll road to the free road at the boundary of the connection node N2. therefore,
The accumulated costs of the first route are road links L01, L12,
Since it is the value obtained by adding the adjustment cost once to the sum of the route costs of L23, it can be seen from Expression (3) that the value is 9. The attribute of the road on the second route changes from the toll road to the toll road with the connection node N1 as a boundary. Therefore, since the accumulated cost of the second route is a value obtained by adding the adjustment cost once to the sum of the route costs of the road links L01 and L13, it can be seen from Expression (4). Cumulative cost of the first route = 1 + 1 + 3 + 2 = 7 (3) Cumulative cost of the second route = 1 + 3 + 5 = 9 (4)

As described above, on the road map having the structure shown in FIG. 6, when the cumulative cost is obtained by the route search operation of the example of FIG. 5, the cumulative cost of the first route is higher than the cumulative cost of the second route. Get smaller. As a result, when the vehicle actually travels, it is preferable to go straight through the intersection as much as possible, but the first route is fixed as the recommended route.

The route search device 9 adds the above-mentioned accumulated cost to
The adjustment cost corresponding to the combination of all the roads connected to the connection node is further added, and the cumulative cost is increased as the route passes through the connection node to which the road links having different road attributes are connected. The adjustment cost is set so that the cumulative cost of routes that pass through connection nodes to which road links with different road attributes are connected is higher than the cumulative cost of routes with only road links with the same road attribute. Is set. This setting method is similar to the example of FIG. 5, and in the example of FIG. 6, the adjustment cost is set to 3.

Specifically, first, the combination determination unit 17
Determines whether the combination of the road attributes of all the road links connected to the connection nodes on each of the first and second routes is a predetermined combination. Figure 6
Example, all road links L connected to the connection node N1
Of 01, L12 and L13, the road link L13 is a free road and the road links L01 and L12 are toll roads. All road links L12 connected to the connection node N2,
Of L23 and L27, the road links L23 and L27 are free roads, and the road link L12 is a toll road. All road links L13 and L2 connected to the connection node N3
3, L36 are all free roads. The predetermined combination is a combination in which the starting point link serving as the starting point of the search among all the road links is a toll road and at least one of the all road links is a free road. Therefore, a combination of road attributes of all road links of the connection nodes N1 and N2 corresponds to this predetermined combination.

Next, when the combination determining unit 17 determines that the combination of road attributes is a predetermined combination for each connection node, the adjusting unit 18 determines the predetermined adjustment cost by Add to the cumulative cost of the route through the connecting node. In the example of FIG. 6, the first route is the connection node N.
Since the combination of the road attributes of all the road links of the connection nodes N1 and N2 passing through 1 and N2 corresponds to a predetermined combination, the adjustment cost is added to the accumulated cost of the first route as shown in FIG. Add twice. Therefore, it can be seen that the accumulated cost of the first route becomes 13 from the equation (5). Since the second route passes through the connection node N1 and the combination of the road attributes of all road links of the connection node N1 corresponds to a predetermined combination, the adjustment cost is 1 in addition to the accumulated cost of the second route.
Add times. Therefore, it can be seen that the cumulative cost is 12 from Equation (6). Therefore, when the cumulative cost of the first route and the cumulative cost of the second route are compared at this point, the cumulative cost of the second route becomes larger than the cumulative cost of the first route, and thus the second route is determined as the recommended route. can do. Cumulative cost of the first route = 1 + 3 + 1 + 3 + 3 + 2 = 13 (5) Cumulative cost of the second route = 1 + 3 + 3 + 5 = 12 (6)

FIG. 8 is a flow chart for explaining the route search operation. The route search operation is performed, for example, when the input device 5 instructs the start of the route search operation. When the start is instructed, the process proceeds from step a1 to step a2.

In step a2, the departure position setting unit 11 sets the departure position, and the destination position setting unit 12 sets the destination position. Specifically, for example, the departure position setting unit 11 causes the operator to input the departure position where the vehicle should start traveling from the input device 5. At this time, the latitude / longitude itself of the departure position may be directly input. In addition, the display device 34 is caused to visually display a road map of an area including the departure position in advance, and the operator is allowed to instruct a point on the road map using a cursor or a touch panel. Alternatively, the latitude and longitude of the departure position may be acquired from the map data. The specific method of setting the destination position is the same as the setting method of the starting position. Further, the departure position setting unit 11 may acquire the own vehicle position searched by the own vehicle position search device 4 and use this own vehicle position as the departure position instead of allowing the operator to input the departure position.

Next, at step a3, the searching unit 13
The first starting point link and the ending point link are set. The search for the road link for the route search may be performed from the departure position to the destination position, or may be performed from the destination position to the departure position. When searching from the departure position toward the destination position, the road link passing through the departure position is set as the first starting point link, and the road link passing through the destination position is set as the end point link that should be the end point of the search. When searching from the destination position toward the departure position, the road link passing through the destination position is set as the first start point link, and the road link passing through the departure position is set as the end point link. One of the connecting nodes at both ends of the first origin link and one of the connecting nodes at both ends of the end link become connecting nodes at both ends of the recommended route.

For example, when the own vehicle position is the starting position, the search is preferably performed from the target position toward the starting position. This is for the following reason. When the vehicle is traveling during the route search operation, the host vehicle position at the start of the route search operation may move behind the host vehicle position at the end of the route search operation in the traveling direction of the vehicle. At this time, if the search is performed from the departure position to the destination position, the route from the vehicle position at the start of the route search to the destination position is determined as the recommended route. In order to move to the starting end of the recommended route, it may be necessary for the vehicle to make a U-turn and return from the vehicle position at the end of the route searching operation to the starting end of the recommended route. Conversely, when the search is performed from the destination position to the departure position, the route from the vehicle position at the end of the route search to the destination position is determined as the recommended route, so the vehicle position at the end of the route search is set. Almost coincides with the start of the recommended route. Therefore, in order to move to the beginning of the recommended route, the vehicle
There is no need to turn and go back. Therefore, in the above case, it is preferable to perform the search from the target position toward the starting position.

For example, in order to set a road link passing through the departure position as the first starting point link, specifically, first, map data representing a road map of an acquisition range determined in advance around the departure position or the destination position is set as map data. Storage device 3
And store it in the memory 25. Then, the search unit 1
3 determines which point on the road link in the acquired map data the departure position is, and sets that road link as the first starting point link. At this time, if the departure position does not match the road link in the map data, the departure position is corrected so as to be a road link near the departure position or a point on the connecting node, and the road passing through the corrected departure position. The link may be the first starting link. The specific method when setting the road link passing through the destination position as the first starting point link and when setting the ending point link is the same as the above method.

Since the total amount of map data is generally very large, it is necessary to make the memory area of the memory 25 extremely large in order to store all the map data in the memory 25. In order to solve this problem, in the process using the map data, only the map data of the road map of the region required for the current process is read from the map data storage device 3 and stored in the memory 25, and the region required for the process is read. Each time the number is changed, the map data of the area is read from the map data storage device 3 and stored in the memory 25. As a result, the memory area of the memory 25 can be made smaller than the size capable of storing all map data, so that the product cost of the navigation device is reduced. Further, it is possible to prevent the processing time from increasing because the data reading time becomes long.

Subsequently, in step a4, the searching unit 14
Set the initial value of the accumulated cost of the route. The initial value of the accumulated cost of the route is individually set to the connecting nodes at both ends of the first origin link, and the initial value is 0, for example. Further, when the traveling direction of the vehicle is known, the initial value set to the connecting node on the front side in the traveling direction is set to 0 among the connecting nodes on both ends of the first starting point link, and is set to the connecting node on the rear side in the traveling direction. The initial value may be set to infinity.
Furthermore, when the first starting point link is a road link passing through the destination position, the initial value set to one of the connecting nodes at both ends of the first starting point link is set to 0.
And the initial value set in the other connection node may be infinite.

Then, in step a5, the searching unit 13
All the connection nodes connected to the connection nodes at both ends of the first starting point link via a single road link are searched from the map data stored in the memory 25. All road links individually interposed between these connection nodes and one of the connection nodes at both ends of the first starting point link are the starting point links next to the search process of the searching unit 13.

Subsequently, in step a6, the searching unit 13 firstly connects, for each of the next origin links obtained in step a5, the first origin link of the connection nodes at both ends of the next origin link. Find the connection node on the opposite side of the connection node. Then, using the obtained connection node as a reference connection node, all connection nodes connected to the reference connection node via a single road link are searched from the map data stored in the memory 25. . When there are a plurality of connecting nodes connected to the reference connecting node, all the connecting nodes are searched.

When the reference connection node is located near the end of the road map represented by the map data currently stored in the memory 25, map data representing a road map of another area following the end is It is read again from the map data storage device 3 and stored in the memory 25. After storing the map, the above-mentioned connection node is searched.

Subsequently, in step a7, the arithmetic unit 14
Selects one of the connection nodes searched in step a6 and sets the road link between the connection node and the reference connection node as a processing link to be processed thereafter. At this time, the reference connection node connects both links between the origin link and the processing link. Next, in step a8, the calculation unit 14 determines the cumulative cost of the route passing through the processing link with one of the connection nodes of the first origin link and the connection node selected in step a7 as both ends. This cumulative cost is the sum of the route costs of all the road links that make up the route.
This accumulated cost is calculated each time in step a8.
For each path, it is sequentially stored in the memory 25 in association with the connection node selected in step a7.

Specifically, in the first processing of the cumulative cost calculation, the calculation unit 14 obtains the cumulative cost of the route including the processing link and the starting point link at the time of searching the processing link in step a6. This starting point link points to the starting point link at the time of the latest search in the search of step a6. This accumulated cost is obtained by adding the route cost of the processing link, the route cost of the starting point link, and the initial value set in the connection node to which this road link is connected among the two initial values set in step a4. It is the value. In the second and subsequent processes of the cumulative cost calculation, the calculation unit 14 firstly calculates the cumulative cost of the route having one of the connection nodes of the first starting point link and the reference connection node at both ends, and the route of the processing link. The cost and are read from the memory 25. The cumulative cost of the route is a cumulative cost associated with the connection node on the opposite side. Further, the search unit 13 adds the route cost of the processing link to the accumulated cost. This sum is the cumulative cost of the route having the connection node at either end of the first origin link and the connection node selected in step a7 as both ends.

At steps a9 and a10, the attribute change determination unit 15 determines whether or not the road attribute has changed at the reference connection node. For example, when determining the attributes of roads to be only toll roads and free roads, specifically, step a
In 9, it is determined whether the road attribute of the starting point link is not a toll road and the processing link is a toll road. Further, in step a10, it is determined whether or not the road attribute of the processing link is not the toll road and the attribute of the road of the starting point link is the toll road. When the determination is affirmative in step a9, the process proceeds from step a9 to step a11, and when the determination is negative, the process proceeds from step a9 to step a10. When the determination is affirmative in step a10, the process proceeds to step a11, and when the determination is negative, the process proceeds to step a12.

At step a11, the adjusting unit 16 causes the cumulative cost calculated at step a8, that is, the accumulation of routes having one of the connecting nodes of the first origin link and the connecting node selected at step a7 as both ends. Increase costs. Specifically, as described in FIGS.
A predetermined adjustment cost is added to the accumulated cost of the route. The method of this increase is not limited to the addition of the predetermined adjustment cost, and may be another method. For example, the accumulated cost of the route may be multiplied by a predetermined value. After the adjustment cost is added, the process proceeds from step a11 to step a12.

That is, when the combination of the attribute of the road of the starting point link and the attribute of the road of the processing link is one of the combinations of the two determination conditions, the attribute of the road is charged at the reference connection node. It is considered that the road will change to a free road or from a free road to a toll road. At this time,
The reference connection node is the entrance or exit of the toll road on the actual road, and the connection node N1, on the road map of FIG.
Equivalent to N3. Therefore, at this time, step a12
Then, the adjustment cost is added to the cumulative cost of the route having one of the connection nodes of the first origin link and the connection node selected in step a7 as both ends. Further, when both the starting point link and the processing link are free roads, or when the starting point link and the processing link are both toll roads, it is considered that the attribute of the road does not change at the reference connection node. At this time, the reference connection node is an inflection point or an intersection on a toll road or an inflection point or an intersection on a toll road on an actual road, and corresponds to the connection node N2 in the road map of FIG. At this time, the adjustment cost is not added to the accumulated cost of the route. Therefore, the cumulative cost of the route from the toll road to the free road via the exit of the toll road and the cumulative cost of the route from the toll road to the toll road via the entrance of the toll road are only toll roads. It is larger than the accumulated cost of the route and the accumulated cost of the route consisting of only free roads.

At step a12, the combination judging section 17
Determines whether the combination of road attributes of all road links connected to the reference connection node is a predetermined combination. For example, in the case of determining road attributes only for toll roads and free roads, specifically, a predetermined combination is that the attribute of the road of the starting link is a toll road and at least one of the all road links is One is a combination of free roads. When the determination is affirmative in step a12, the process proceeds to step a13, and when the determination is negative, the process proceeds to step a14. In step a13, the adjusting unit 18
Adds a predetermined adjustment cost to the cumulative cost calculated in step a8, that is, the cumulative cost of the route having one of the connecting nodes of the first origin link and the connecting node selected in step a7 as both ends. To do. After the adjustment cost is added, the process proceeds from step a13 to step a14.

When the starting link is a toll road and at least one of all road links is a free road,
On an actual road, the reference connection nodes are the entrances and exits at the end of the toll road, or the entrances and exits in the middle of the toll road, that is, the connection nodes N1 and N2 in the road map described above with reference to FIG. Equivalent to. Therefore, at this time, in step a13, the adjustment cost is added to the accumulated cost of the route having one of the connection nodes of the first origin link and the connection node selected in step a7 as both ends. Further, when all road links are toll roads, this connection node corresponds to an inflection point or an intersection on the toll road or an inflection point or an intersection on the toll road in the actual road. At this time, the adjustment cost is not added to the accumulated cost of the route. When the starting point link is a free road, the adjustment cost is not added to the accumulated cost of the route regardless of the combination of road attributes of all road links.

As a result, the cumulative cost of the route passing through the connection nodes corresponding to the entrance and exit of the toll road is
Regardless of whether the vehicle moves from the toll road to the free road through the entrance and exit, and whether the vehicle moves from the toll road to the free road through the entrance and exit , The cumulative cost of routes that do not pass through connection nodes corresponding to the entrances and exits of toll roads.

At step a14, the confirming section 19 determines whether or not one of the connection nodes of the first starting link is connected to step a.
It is determined whether or not there are a plurality of routes passing through different road links with the connection node selected in 7 as the both ends. Such routes correspond to the first and second routes in FIGS. 5 and 6. When there is only one route, the process directly proceeds from step a14 to step a15. At this time, the accumulated cost of the route is directly associated with the node selected in step a7. When the route to the selected node already exists, the process proceeds from step a14 to step a15, and the route with the smallest accumulated cost is selected from these routes. This means that the selected route has been determined as the route from the first origin link to the processing link among the routes passing through this processing link. Further, the accumulated cost of this route is determined as the accumulated cost associated with the connection node selected in step a7. by this,
There is 1 route that has both ends of the connection node on either side of the first origin link and the connection node selected in step a7.
Limited to books. This route becomes part of the recommended route.

At this point, the processing of steps a9 to a13 is concerned with the route in which the vehicle moves from the toll road to the toll road or vice versa through the entrance and exit of the toll road, and to the entry / exit of the toll road. The cumulative cost of routes that pass through connection nodes corresponding to entrances and exits of toll roads is higher than the cumulative costs of other routes. Therefore, comparing the accumulated costs at this point, the accumulated costs of the second route in FIGS. 5 and 6 are
It is smaller than the accumulated cost of the first route. Therefore,
The second route is selected. As a result, steps a9-
By the processing of a15, it is possible to prevent the above two types of routes from becoming part of the recommended route.

At step a16, the decision unit 19 determines whether or not the processes at steps a7 to a15 have been completed for all the connection nodes searched at step a6. In other words, it is determined whether or not the calculation of the accumulated cost of all the routes having both ends of one of the both ends of the first origin link and each of the connection nodes searched in step a6 has been completed. When an uncalculated route remains, the process returns from step a16 to step a7, and in step a7, a road interposed between the connection node not yet processed and the connection node on the opposite side obtained in step a6. The link is selected as the processing link, and the processing of steps a8 to a15 is performed. When the calculation of all the routes is completed, the process proceeds from step a16 to step a17.

At step a17, the decision section 19 decides whether or not the recommended route can be decided. Specifically, this determination determines whether or not the connection node selected in step a7 is one of the connection nodes at both ends of the end point link. The processing operation of this step corresponds to the operation of the determining means in the claims. If not, the process returns from step a17 to step a6.
After that, any one of the connection nodes searched in step a6 is set as the next reference connection node, and the road link between the reference connection node and the original reference connection node is set as the origin link. The processing operations of steps a6 to a17 are repeated until one of the connection nodes at both ends of the end point link is searched for in step a6. As a result, the route selected in step a15 is extended so as to sequentially approach the end point link. Step a
When the connecting node selected in 7 coincides with either one of both ends of the end point link, the determining unit 19
Has its connection node and one of the connection nodes at both ends of the first origin link as both ends, and the step a15
The route passing through the route selected in step 1 is confirmed as the recommended route. The confirmed recommended route is stored in the search result storage unit 17. After storing the recommended route, the route searching operation is ended in step a18.

In the route search operation described above, when the accumulated costs of the two routes match, it is difficult to set one of them as the recommended route. In this case, the decision unit 19 compares the factors other than the accumulated cost and determines the recommended route. For example, comparing the ratio of toll roads and free roads in the route,
The route with the largest percentage of free roads is confirmed as the recommended route.
The determining unit 19 also compares the route lengths of the entire routes and determines the route with the shorter route length as the recommended route. This makes it possible to determine the recommended route even when the accumulated costs match.

By the series of operations described above, FIGS.
In the road map of, the second route can be decided as the recommended route. Also, in this road search, if the route that passes through the main line of the toll road over a long distance of, for example, 1 km or more is an appropriate route, two routes, that is, the route through the toll road parallel to the main line of the toll road and the above route. May be searched for. At this time, among the accumulated costs obtained by the calculation unit 14, the accumulated cost of the route passing through the main line of the toll road is the route cost of each road link forming the main line is more than the route cost of each road link forming the free road. Since it is also small, it is smaller than the cumulative cost of routes passing through free roads. Further, since the toll road does not move from the toll road to the toll road through the entrance and exit of the toll road, the adjustment cost is not added in step a11. Therefore, the accumulated cost of the route passing through the main line of the toll road is sufficiently smaller than the accumulated cost of the route passing through the toll road. Therefore,
In this case, the route passing through the toll road can be determined as the recommended route.

Further, of the above two routes, the entrance and exit of the toll road are connected to the toll road, and a road link is further provided between the entrance and the exit within the toll road so that the distance is 1 km or more. At some time, the adjustment cost is added to the cumulative cost of the route passing through the toll road. At this time, the difference between the two accumulated costs obtained by the calculation unit 14 is larger than the added amount of the adjustment costs. As a result, the cumulative cost after adjusting the route passing through the toll road is smaller than the cumulative cost after adjusting the route passing through the toll road.Therefore, in this case as well, the route passing through the toll road is set as the recommended route. Can be confirmed.

As described above, in the route search operation of the present embodiment, when a detour having a shorter route length and a different road attribute is added to a road having a certain road attribute,
It is possible to avoid making a route passing through the detour a recommended route. Further, when a road having a different road attribute is connected to a road having a certain road attribute, and the two roads are further connected in the traveling direction from the connection point via the bypass route, a route passing through the bypass route. Can be avoided as the recommended route. Therefore, by the route search operation using the Dijkstra method, in the above case, an appropriate route suitable for the actual traveling of the vehicle can be determined as the recommended route.

In the above route search operation, the attributes of roads are limited to toll roads and free roads. The combination of the presence or absence of the change of the road attribute and the road attribute is not limited to the toll road and the free road, and may be the attribute of other roads. For example, instead of the toll road / free road, the attributes of the road may be national road / prefectural road / narrow street, and the route searching operation may be performed as described above.

This route search device 9 is, as described above,
It can be realized by the arithmetic processing of the central processing unit 23. Therefore, by storing the program and the map data for realizing the above-described search processing device 6 in a storage medium such as a floppy disk and installing the program and the map data in, for example, a personal computer, the above-mentioned route can be obtained. The search device 9 can be realized.

The route searching device according to the second embodiment of the present invention will be described below. This route search device is the first
Compared with the route search device 9 of the embodiment, only the detailed operation of the attribute change determination unit 15 is different, and in the schematic electrical structure of the route search device 9, the connection relation of each component, the route search device 9 Electrical structure and attribute change determination unit 1
The operation of the components other than 5 is the same. The same components as those of the route search device 9 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 9 is a flow chart for explaining the route search operation carried out by the route search device. This flowchart includes steps for performing the same operations as those in the flowchart of FIG. 8, and description of steps for performing the same operations is omitted. When the route search operation is started, the process proceeds from step b1 to step b2. The operation of steps b2 to b8 is the same as the operation of steps a2 to a8 in the flowchart of FIG.

The attribute change determination section 15 determines in step b9 that
It is determined whether the processing link is the entrance line of the toll road. If it is an entrance line, the process proceeds from step b9 to step b11. If it is not the entrance line, steps b9 to b1
Go to 0. At step b10, the attribute change determination unit 15
Determines whether the processing link is an exit line of a toll road. If it is an entrance line, steps b10 to b1
If it is not the entrance line, the process proceeds from step b10 to step b12. At step b11, the adjusting unit 16
A predetermined adjustment cost is added to the cumulative cost of the route having the first origin link and the processing link at both ends. The processing operation of steps b11 to b18 is the same as that of steps a11 to a18 in the flowchart of FIG. Step b18
When it is determined that the node has reached either one of both ends of the end point link, the processing operation of the flowchart ends in step b18.

When the processing link is the entrance line and the exit line of the toll road, the road link connected to one of the connection nodes at both ends of the processing link is a toll road, and the other connection node is the free road. The road link connected to is a toll road. Therefore, the road attribute changes at any one of the connecting nodes at both ends of this processing link. Therefore, if the processing link is the entrance line or the exit line of the toll road, the attribute of the road changes among the routes passing through the processing link. Therefore, as described above, by determining whether or not the road attribute of the processing link is a predetermined attribute, it is possible to determine whether or not the road attribute of the connection link in the route has changed. Therefore, for the same reason as in the first embodiment, an appropriate route suitable for the vehicle to actually travel can be determined as the recommended route.

In the above description, since the road attributes are limited to toll roads and free roads, the predetermined attributes are the entrance and exit lines of the toll road. The predetermined attribute is not limited to the above-mentioned attributes as long as the attribute of the road can change the attribute of the road in one of the road links of the attribute. For example, the predetermined attribute may be an entrance line and an exit line to a parking lot associated with a highway. By setting the predetermined attribute as such an attribute, it is possible to prevent the route passing through the parking lot from passing through the highway from being fixed as the recommended route.

Further, in this determination method, the determination is performed based on the road attribute of only the processing link. Whether or not the road link is the entrance line and the exit line of the toll road is stored in advance in the map data as an attribute of the road of the road link. Therefore, it is possible to determine the presence or absence of the attribute change only by acquiring only the road attribute of the processing link from the map data storage device 3. Therefore, it is not necessary to acquire the attribute of the road of the starting point link when determining whether the attribute has changed. Therefore, the determination method becomes easy.

Further, in this determination method, even if the attribute of the road changes from the toll road to the free road in the middle of the route and the attribute of the road does not change from the toll road to the toll road, the entrance line and the exit line are determined. The adjustment cost is added to the accumulated cost of the route only by passing. As a result, even in the example of FIG. 6 described above, the cumulative cost of the first route becomes larger than the cumulative cost of the second route only by performing the processes of steps b9 to b11. Therefore, in the route search device of the second embodiment, the processing operation of steps b12 and b13 can be omitted. Therefore, the route search operation can be further simplified.

The route searching device according to the third embodiment of the present invention will be described below. This route search device is the first
Compared with the route search device 9 of the embodiment, the route search device 9
The same components as those in FIG. This route search device includes a map data storage device 3 and a search processing device. The search processing device includes a departure position setting unit 1
1, a target position setting unit 12, a search unit 13, a connection determination unit, a calculation unit, and a determination unit. Each of these units is a virtual circuit realized by the arithmetic processing of the central processing unit 23.

FIG. 10 is a schematic diagram showing a specific structure of the searched road data. The searched road data shown in FIG. 10 has a data structure similar to that of the searched road data shown in FIG. 4 and includes the same data.

The searched road data includes M + 1 pieces of node information. The nth node information of each node Nn is the number of search nodes x, x connection node information, x connection link information,
And link information individually included. Each road link Lna
The connection link information of includes traffic regulation, road type, width, link length, and route cost. This route cost is
It is the route cost of the road link Lna. Each node information is the same as the node information of the searched road data in FIG. 4 except that the route cost is added to the connection link information.

The link information of the node information n is {xx
(X-1)} are included. The inter-link information related to the route Xbna includes traffic regulation, route cost, and combination cost. The route cost of the node Nn of the route Xbna is, for example, the road link Lbn on the entry side to the node Nn and the road link Lna on the exit side from the node Nn.
The other cost is the route cost of the node Nn determined by a combination of the above and the other cost is determined by adding the adjustment cost to the route cost of the node Nn of the route Xbna. This adjustment cost is equal to the adjustment cost added by the adjustment units 16 and 18 of the route search device of the first embodiment.

FIG. 11 is a flow chart for explaining the route search operation carried out by the route search device described above. This flowchart includes steps for performing the same operations as those in the flowchart of FIG. 8, and description of steps for performing the same operations will be omitted. When the route search operation is started, the process proceeds from step c1 to step c2. Steps c2 to c
The operation of No. 7 is steps a2 to a of the flowchart of FIG.
It is equivalent to the action of 7.

In step c8, the connection determination unit determines whether or not the combination of the starting point link and the processing link is a predetermined combination. In this determination, for example, from the link number of the road link that is the starting link and the link number of the road link that is the processing link, the route formed by these two road links is the route in which the additional cost is stored in the searched road data. Determine if there is. When this route is a route in which another cost is stored, the process proceeds from step c8 to step c9, and when this route is not a route in which another cost is stored, the process proceeds from step c8 to step c10.

At step c9, the calculating section obtains the accumulated cost of the route having the first starting point link and the processing link at both ends by using the different cost for combination. In particular,
First, the route cost of the route consisting of the starting point link and the processing link is read from the above-mentioned link information. Further memory 2
From 5, the accumulated cost of the route having one of the two ends of the first origin link and the other of the ends of the origin link opposite to the reference connection node is read. . The path cost and the accumulated cost are added, and the sum is calculated, and the sum is calculated as a connection node on either side of the first origin link and a connection node on the opposite side of the reference connection node from both ends of the processing link. Let the cumulative costs of the routes with and at both ends. As a result, the above adjustment cost can be added to the accumulated cost of the route.

In step c10, the arithmetic unit uses the route cost of the route to connect one node of the first origin link and the connecting node on the opposite side of the reference node from both ends of the processing link. Calculate the cumulative cost of routes with and at both ends. The specific processing of this calculation method is the same as the calculation method of step c9, except that the route cost of the route is used instead of another cost. When the cumulative cost is calculated in steps c9 and c10, the process proceeds to step c11. The processing operations in steps c11 to c15 are the same as steps a14 to a18 in the flowchart of FIG. When it is determined in step c14 that one of the connection nodes on the end point link is reached, step c
At 15, the processing operation of the flowchart ends.

In the route search operation of the third embodiment, the processing operation for adding the adjustment cost to the accumulated cost is included in the processing operation for calculating the accumulated cost. Therefore, steps a9- in the flowchart of FIGS.
The processing of a14 and b9 to b14 is omitted, and instead, the determination operation of step c8 and the arithmetic operation of step c9 are added. As a result, the route search operation of the third embodiment is simpler than the route search operation of the first and second embodiments. Therefore, it is easy to implement.
Further, in the determination of step c8, since the link numbers themselves of the starting link and the processing link are compared, the attribute of the starting link road and the attribute of the processing link road from the map data storage device 3 are used for this determination. There is no need to read and compare and. As a result, the determination in step a8 is made in steps a9 and a1 of the route search operation of the first and second embodiments.
0, a12; b9, b10, b12,
The processing operation is simplified. This can further simplify the route search operation.

[0141]

As described above, according to the present invention as set forth in claims 1 and 2, after searching a route from the starting position to the destination position, all route costs added to the road links constituting the route are searched. to add. Furthermore, weighting is performed to adjust the sum of the route costs in response to the presence or absence of changes in the attributes of the roads in the route, and the combination of the road attributes of all road links in the route is set to a predetermined combination. Weighting to adjust the sum of the route costs in response to the number of times the node passes, and the adjusted sum of the route costs is compared, and the route with the smallest sum of the route costs is determined as the recommended route. To do. Therefore, when a detour consisting of road links having the attribute of a road with a low route cost is added to a certain road, the sum of the route costs of the routes passing through the detour is the sum of the route costs of the routes not passing through the detour. Even if it is smaller than the above, a route that does not pass through the detour can be searched as the recommended route. Further, when two roads having different road attributes are connected and further connected again from the node via the detour in the forward direction of travel, it is suitable for a vehicle passing through the detour to actually travel. It is possible to prevent the undetermined route from being determined as the recommended route.

[0142]

[0143]

[0144]

[0145]

Further, according to the present invention, the search means searches for the recommended route using the route cost. As a result, weighting can be effectively used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of a navigation device 1 including a route search device 9 according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a specific electrical configuration of the navigation device 1.

FIG. 3 is a schematic diagram showing a road map.

FIG. 4 is a schematic diagram showing the configuration of search map data.

FIG. 5 is a schematic diagram of a road map for schematically explaining a route search operation.

FIG. 6 is a schematic diagram of a road map for schematically explaining a route search operation.

FIG. 7 is a schematic diagram of a road map for schematically explaining a route search operation.

FIG. 8 is a flowchart for explaining a route search operation.

FIG. 9 is a flowchart for explaining a route search operation performed by the route search device according to the second embodiment of the present invention.

FIG. 10 is a schematic diagram showing a configuration of search map data used in the route search device according to the third embodiment of the present invention.

FIG. 11 is a flowchart illustrating a route search operation performed by the route search device according to the third embodiment of the present invention.

[Explanation of symbols]

1 Navigation device 3 Map data storage 4 Own vehicle position search device 5 Input device 6 Search processing device 7 Route guidance device 8 output devices 11 Departure position setting section 12 Target position setting section 13 Search section 14 Operation part 15 Attribute change determination unit 16,18 Adjustment unit 17 Combination determination section 19 Confirmation Department 20 Search result storage

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969 G09B 29/00-29/10

Claims (3)

(57) [Claims] 1. A map data storage means for storing map data including road data including a plurality of road links and a plurality of nodes, and attribute data regarding road attributes, and a departure position setting for setting a departure position on the map data. A route search device comprising: means, destination position setting means for setting a destination position on map data, and search means for reading out map data from the map data storage means and searching for a recommended route connecting the departure position and the destination position. The search means is an attribute change determination means that determines that a road attribute changes when a node is an entrance or an exit of a toll road, and among all road links connected to the node, the road link that is behind the traveling direction is When the road is a toll road and at least one of all road links is a free road, the combination of road attributes is predetermined. When the road attribute change is determined by the attribute combination determination means and the attribute change determination means, predetermined weighting is applied to the route, and the road is determined by the attribute combination determination means. When the combination of the attributes is determined to be a predetermined combination, the route search device includes an adjusting unit that performs predetermined weighting on the route. 2. Map data storage means for storing map data including road data consisting of a plurality of road links and a plurality of nodes, and attribute data regarding road attributes, and departure position setting for setting a departure position on the map data. A route search device comprising: means, destination position setting means for setting a destination position on map data, and search means for reading out map data from the map data storage means and searching for a recommended route connecting the departure position and the destination position. The searching means includes an attribute change determining means that determines that the attribute of the road changes when one of the two continuous road links is a toll road and the other is a free road, and Of all the road links to be connected, the road link in the backward direction is the toll road, and at least one of all the road links When one is a free road, the attribute combination determination means determines that the combination of the road attributes is a predetermined combination, and when the attribute change determination means determines that the road attribute changes, the route is previously determined for the route. A predetermined weighting, and further, when the attribute combination determining means determines that the combination of road attributes is a predetermined combination, it further comprises an adjusting means for performing a predetermined weighting on the route. Route search device. 3. The map data storage means stores information about a route cost preset based on a time required for a vehicle to travel on an actual road, a length of a road represented by a road link, and a width of the road. The route search device according to claim 1 or 2, wherein the route is stored, and the search unit searches for a recommended route based on a route cost.