JP2897675B2 - Route information providing method and apparatus, and route information providing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
It relates to guidance of a route to a destination by providing information from a traffic control center.

[0002]

2. Description of the Related Art As a method of route guidance to a destination,
Car-mounted navigation system, CD-ROM
There is a method of calculating the shortest route to a destination based on a digital map stored in the like. However, according to this method, information that changes every moment such as traffic congestion or an accident cannot be captured, and sometimes a non-shortest route may be calculated.

[0003] As another method, a traffic control center calculates the shortest route to all destinations at predetermined times, and stores the route information in a road beacon arranged at a key point on the road. In a road beacon, when a vehicle indicates a destination and a request for providing route information is made, there is a method of returning optimal route information to the vehicle.

[0004]

In this method, the traffic control center determines in advance the shortest route that reflects the changing road conditions in consideration of time-varying information such as traffic congestion, accidents, and weather conditions. The calculation can be performed for each time the data is sent, and the result can be sent to the road beacon. However, in recent years, the number of roads has become enormous, and road conditions are constantly changing. Therefore, the traffic control center must constantly perform enormous calculation processing, which takes a long calculation time.

[0005] Further, the amount of information transmitted to the road beacon also becomes large. Therefore, there is a need for a route information providing method and system that can reduce the processing load on the traffic control center and the communication line with the road beacon. Therefore, an object of the present invention is to solve the above technical problems and to provide a route information providing method and apparatus capable of reducing the processing amount of a traffic control center and the load on a communication line with a road beacon. .

[0006]

Means and Actions for Solving the Problems (1) The route information providing method according to claim 1 for achieving the above object comprises: (a) a route tree extending from a departure point in a route providing area; Each is calculated according to a plurality of route calculation conditions based on various road traffic conditions and stored in a database. (B1) A plurality of combinations of a fixed number of route trees are initially set from the route trees in the database and stored as groups. (B2) calculate the evaluation function P of each group, and (b3) calculate the evaluation function P for some of the groups having the preferable evaluation function P so that the evaluation function P changes in a more preferable direction. Partially intersect the path tree that constitutes the group, (b4) the (b2) (b3)
Is repeated a plurality of times until the evaluation function P substantially converges, and the group finally obtained is registered. (D) At each predetermined time, each route included in the registered group is registered. For the tree, the link cost obtained according to the route calculation condition based on the road traffic situation at the time is calculated and any one or more route trees are selected, and (e) at least the destination is indicated by indicating the route information. A method for indicating a route based on the one or more route trees when a provision request is made.

According to the above method, first, the route tree is calculated by a known method according to a plurality of route calculation conditions based on various road traffic conditions, and stored in a database. Next, it is necessary to indicate the optimum route using the route tree stored in the database. However, in a simple consideration, at each predetermined time, the Although it is sufficient to show the optimal route in the road traffic condition at the time using the route tree obtained under the same route calculation condition as the route calculation condition based on the road traffic condition, if a single route tree is used, If the route calculation conditions such as accidents and weather conditions change accidentally, the optimum route cannot be shown.

Therefore, a combination of a fixed number of route trees is selected from the route trees in the database to form a group, and based on each route tree in the group, the road traffic condition at that time is determined at every predetermined time. According to the route calculation condition based on, the link cost is calculated,
As a result, one or a plurality of route trees are selected, and when at least a destination is indicated and a request for providing route information is made, a route to the destination is determined based on the one or more route trees. Show.

[0009] The path tree constituting the group is
The question remains of how to choose. When all the path trees in the database are used, the number of path trees is too large and the processing time increases, and the path tree calculated according to unique path calculation conditions often cannot show the shortest path . Therefore, according to the methods (b1) to (b4), an evaluation function of a group is defined, and the path trees constituting each group are rearranged so that the group converges to a group showing a preferable evaluation function. selection,
Sort out. (2) The invention of claim 2 is different from the invention of claim 1 in that the departure place of the route tree is not limited to one point, but is extended to all points in the route providing area. Therefore, it is possible to provide route information from an arbitrary departure point to a destination. (3,4) In the inventions according to claims 3 and 4, when the route tree is first obtained, the route tree is obtained by using the route calculation conditions at a past time or by the route calculation conditions averaged during the past period. There is only a difference.

In the former case, a route tree that reflects the constantly changing road traffic conditions can be obtained. In the latter case, since the averaging operation is performed, it is possible to prevent a unique path tree from appearing due to a sudden change. (5) The invention described in claim 5 exemplifies how to select a route calculation condition. For example, by classifying groups where traffic conditions are completely different, such as weekdays and holidays, using a route tree closer to the route calculation conditions at the time of route calculation request,
We can provide an accurate route. (6) The invention according to claim 6 rearranges the path trees constituting each group, and selects and sorts the groups so as to converge to a group showing a preferable evaluation function. The method is prescribed. If the dispersion of the evaluation function is large in the initially set group, the convergence is delayed. Therefore, the route calculation condition of the group finally registered corresponding to the neighboring departure point is used.

As a result, the convergence can be accelerated, and the processing time can be shortened. (7) The invention of claim 7 shows a method of calculating the evaluation function P. A value obtained by calculating the path cost error of each path tree when the path calculation condition is changed and averaging the obtained path cost over time j and destination k is considered to be an appropriate evaluation value for the individual path tree. (8) The invention of claim 8 stipulates that when partially intersecting the path trees constituting the group, the constituent path trees are intentionally replaced, that is, a mutation is derived.

When rearranging the path trees constituting each group and selecting and selecting the groups so as to converge to a group exhibiting a preferable evaluation function, if the original components of the group are not appropriate, the convergence may occur. It does not converge to a good value. Therefore, by exchanging elements intentionally completely, we expect the emergence of excellent groups. (9) The invention according to claim 9 is configured such that when a plurality of combinations of route trees are initially set from the route tree in the database,
Rather than performing the process for all the applicable path trees in the database, the applicable path trees are classified, and for each classification, the group is selected by performing the operations (b1) to (b4) to form the selected group. From (b1)
It specifies that the operation of (b4) be performed.

Such processing is effective when the original number of path trees is large and the number of combinations is too large even if groups are set out of them, and processing cannot be performed. (10) The invention according to claim 10 is characterized in that in step (d) according to claim 1 or 2, each route tree included in the registered group for each destination at each predetermined time. Calculate and compare the route cost to the destination obtained according to the route calculation condition based on the road traffic condition at the time, select one or more route trees, and change the route tree to the destination In step (e), when at least a destination is requested to provide route information, a route is determined based on one or more route trees associated with the destination. It is characterized by showing.

As described above, for each destination, the route cost to the destination is calculated and compared, and one or a plurality of route trees are selected in association with the destination. As many as one or more path trees correspond to the number. However, one or more optimal route trees are selected for each destination, so that an optimal route to the destination is obtained. (11) In the invention according to claim 11, in step (d) according to claim 1 or 2, the destination is limited for each route tree included in the registered group at a predetermined time. Instead, the link cost pattern corresponding to each route tree is compared with the link cost pattern based on the road traffic condition at the time, and one or more route trees are selected, and the procedure ( In e), when at least a destination is indicated and a request for providing route information is made, a route to the destination is indicated based on the one or more route trees.

As described above, without limiting the destination, for each of the route trees included in the registered group, the link cost pattern corresponding to each route tree and the link cost based on the road traffic condition at the time are described. The resulting "one or more path trees"
Is only one way. Therefore, the amount of information to be handled decreases. (12) Claim 12 describes a route information providing apparatus according to the same invention as the route information providing method according to claim 1 or 2. (13) Claim 13 describes a route information providing system that realizes the route information providing method according to claim 2.

This system comprises a traffic control center, a communication device disposed at various places in a road traffic network for two-way communication with vehicles, and a communication line connecting the traffic control center and the communication device. A database for calculating and storing route trees extended from each departure point in the route providing area according to a plurality of route calculation conditions based on various road traffic conditions, and a group of route trees in the database. a registration unit for obtaining and registering by the procedure of (b1) to (b4), a first transmission unit for transmitting the data of the path tree included in the group registered by the registration unit to the communication device, At each time, the registered group is searched, and for each route tree included in the group, the route based on the road traffic condition at the time is searched. Second transmission means for calculating the link cost obtained in accordance with the calculation conditions, selecting one or a plurality of path trees, and transmitting the identification information to the communication device, wherein the communication device comprises: A storage unit for storing the path tree data transmitted from the first transmission unit, and a storage unit corresponding to the identification information transmitted from the second transmission unit.
Route selection means for selecting one or more routes from a vehicle to a destination requested to provide route information based on one or more route trees.

To explain the communication procedure of this system, the traffic control center creates a database according to the procedure of claim 2 (a), and the most suitable group by the procedure of claims 2 (b1) to (b4). And register for it. Further, the route data of the route tree included in the registered group is transmitted to the communication device and stored in the communication device. Further, the traffic control center performs, for each predetermined time, a link cost obtained for each route tree included in the registered group according to a route calculation condition based on the road traffic condition at the time, and calculates Select one or more path trees.

Then, if the identification information of the selected one or more path trees is transmitted to the communication device, the communication device transmits the identification information to the destination actually indicated by the vehicle from the transmitted identification information. One or more routes to the destination to be indicated to the vehicle can be specified and returned to the vehicle based on the route tree corresponding to the corresponding one or more identification information.

[0019] As described above, the communication device, based on the one or more route trees, corresponds to one or a plurality of routes from the vehicle to the destination to be shown to the vehicle. Since it is only necessary to select and indicate the route, the processing load on the communication device is almost negligible. In addition, since the traffic control center has already registered a group consisting of a fixed number of route trees, the traffic control center uses the route tree included in this group and calculates the route tree according to the route calculation conditions based on the road traffic conditions at the time. By simply performing a simple process of calculating the link cost of the above, one or a plurality of optimal route trees at that time can be obtained. (14) Claim 14 describes a route information providing system that realizes the route information providing method according to claim 10.

This system, when compared with the system according to the thirteenth aspect, computes a route cost obtained at a traffic control center at predetermined times according to a route calculation condition based on a road traffic condition at the time. More specifically, a method of comparing and selecting any one or a plurality of path trees is specified. That is, the second transmission means of the traffic control center searches the registered group for each predetermined time and for each destination, and for each route tree included in the group, the road traffic at that time is searched. Calculate and compare the route cost to the destination obtained according to the route calculation conditions based on the situation,
One or a plurality of route trees are selected in association with the destination, and the identification information is transmitted to the communication device.

The route selection means of the communication device stores the route tree data transmitted from the first transmission means, and provides the route information from the vehicle among the identification information transmitted from the second transmission means. One or more routes to the destination to be shown to the vehicle are selected based on one or more route tree data corresponding to the identification information corresponding to the requested destination.

As described above, the traffic control center calculates and compares the route cost to each destination and selects one or a plurality of route trees in association with the destination. Therefore, it is necessary to calculate the number of times corresponding to the number of destinations, and the identification information to be sent to the communication device is also the number corresponding to the destination. However, since one or a plurality of optimal route trees are selected for each destination, the optimality of the route to the destination to be indicated to the vehicle is improved. (13) Claim 15 describes a route information providing system that realizes the route information providing method according to claim 11.

[0023] The second transmitting means of the traffic control center searches the registered group at a predetermined time, and for each route tree included in the group,
Without limiting the destination, the link cost pattern corresponding to each route tree is compared with the link cost pattern based on the road traffic conditions at the time, and one or more route trees are selected. Transmitting the identification information to the communication device, wherein the path selection unit of the communication device includes one or more of the path trees corresponding to the identification information among the identification information transmitted from the second transmission unit. Based on the data, one or a plurality of routes from the vehicle to the destination requested to provide route information are selected.

Thus, without limiting the destination, for each route tree included in the registered group, the link cost pattern corresponding to each route tree and the link cost based on the road traffic condition at the time are described. The resulting "one or more path trees"
Is only one way. Therefore, the amount of processing calculated by the traffic control center decreases, and the amount of information to be transmitted from the traffic control center to the communication device also decreases.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. <System Configuration> FIG. 2 shows a configuration in which a traffic control center B and a road beacon C are connected by a communication line L, and two-way communication is performed between the road beacon C and the vehicle by light or radio waves. .

More specifically, the road beacon C
Is a modem 210, a control device 220, and a transceiver 23.
0 is provided. The traffic control center B includes a map-dedicated memory 110, a control device 120, a modem 130, and a database 140. In the map dedicated memory 110,
Data (referred to as link data) relating to links connecting points corresponding to major intersections in the route providing area is stored.

The stored link data includes an identification number of each link, latitude and longitude corresponding to both ends of the link, a link cost when passing through the link (the actual length of the road and the road type (expressway or national road). And the standard speed of the vehicle corresponding to that type), the link length (distance), a pointer to another approach link (also referred to as the previous link) connected to the origin of the link, It includes a pointer to another exit link (also referred to as a post link) connected to the end point of the link, a connection cost, and the like.

The case where this link is viewed from the starting point of the link is referred to as an exit link, and the case where this link is viewed in the opposite direction from the end point of the link is referred to as an incoming link. The connection cost is the cost of turning right or left or going straight to exit from this link and enter the next link.
For example, when entry is prohibited, the connection cost is infinite, and when there is a traffic light, the cost takes into account the average signal waiting time when turning right or left or going straight.

The above link cost and connection cost are usually
The cost when traveling at the legal speed is used, but if the latest traffic information comes into the traffic control center B, a change according to the content is made. For example, when a link is interrupted due to an accident, the link cost of this link is infinite until traffic resumes. If the up lane of a certain road is congested, the cost of the link is increased in accordance with the congestion.

There are the following two methods for the traffic control center B to obtain the latest traffic information. One is
This is a method of knowing traffic information by vehicle detectors installed by the traffic control center B at various places on the road, helicopters navigating above the sky, and the like. The other is the actual value of the route cost of the currently traveling road from the vehicle actually traveling on the road via the road beacon C (the time required to reach the road beacon C from each departure point). ) Is collected and counted. In the former method, traffic information can be easily collected, but accuracy is reduced. In the latter method, although detailed information is high in accuracy, it takes time for the computer to perform the tallying process.

FIG. 4 shows a specific form of the link of the link data stored in the map dedicated memory 110. For example, if the road map is as shown in FIG. 3, the link is, as shown in FIG.
Link L ₁₂ connecting intersections N ₁ and N ₂ , intersection N ₂
Link connecting to N ₁ from L _21, represented as such...

The control device 120 of the traffic control center B
The route tree extended from each point in the route providing area is calculated in accordance with a plurality of route calculation conditions based on various road traffic conditions and stored in the database 140, and a plurality of combinations of a predetermined number of route trees from the route tree are calculated. Initially set as described above and stored as a group (hereinafter, referred to as “individual” in this embodiment), an evaluation function P of each individual is calculated, and for each of several individuals having a preferable evaluation function P, Then, the path trees constituting the individual G are partially crossed so that the evaluation function P changes in a more preferable direction, and the above procedure is repeated a plurality of times until the evaluation function P substantially converges. The obtained individual is registered, and the path tree information of the registered individual is transmitted to the communication device, and is included in the registered individual at every predetermined time. For the route tree, the link cost obtained according to the route calculation condition based on the road traffic condition at the time is calculated, one or more route trees are selected, and the identification number of the selected route tree is communicated. And a function of transmitting to the device.

The control device 220 of the road beacon C stores the data of the route tree transmitted from the traffic control center B, and stores the data of one or a plurality of route trees corresponding to the identification information transmitted from the traffic control center B. And a function of selecting one or a plurality of routes from the vehicle to the destination requested to provide the route information, and communicating with the vehicle.

The above processing is called offline processing, and the processing is called online processing. Is performed more frequently than offline processing, but belongs to the middle of the two in the sense that real-time processing is not required unlike online processing, but is included here in the online processing for the moment. These functions will be described in detail below. <Offline processing> In the traffic control center B, the control device 120 uses the link cost information at each time to
A route tree starting from each major intersection link (referred to as a “reference route tree”) is calculated, and the calculated reference route tree is stored in the database 1 in the traffic control center B.
40. Since there are usually thousands of major intersections in the route providing area, there are thousands of reference route trees stored in the database 140.

Further, the calculation of the reference route tree is based on the season, time zone, month, day of the week, weekday / holiday,
It is calculated and stored for each one or a combination of the time zone and the presence or absence of the entertainment. For example, if we take the season, the day of the week, and the time, the four seasons, the seven days of the week,
If calculated once every 0 minutes, the number of reference path trees would be a huge number of files of (thousands) × 4 × 7 × 24 × 6.

Instead of storing the result calculated based on the link cost information at each time, the reference route tree is calculated and stored based on the average link cost information over a certain range of time (for example, 10 minutes). You may keep it.
This can eliminate variations due to accidental events. It is sufficient if the file of the reference route tree is updated in a sufficiently long period of one month, six months or one year in consideration of a change in traffic regulation such as a new road or one-way traffic.

The files of the reference path tree are not used by referring to all the files when performing the above calculation. Of course, only the reference route tree starting from the link of the intersection where the road beacon C is located is used, but the season, time zone, day of the week, weekday / Whether there is a holiday or not and whether there is an entertainment (these are referred to as “route calculation conditions”) are determined, and only the reference route tree that matches the result of this determination is referred to.

Accordingly, if one vehicle requests route information to be provided on Sunday morning, holiday, and no entertainment during the spring morning, the same route calculation condition as in the past is satisfied. A total of 25 reference path trees with different times calculated every 10 minutes from hour to 12:00 will be referred to. However, from a practical point of view, if the conditions are too subdivided, the amount of data becomes enormous and the control becomes complicated. Therefore, it is preferable to determine the conditions in consideration of economy and efficiency. In the simplest case, it is conceivable to distinguish between two types of holidays and weekdays. Also, in the city center, the situation of midnight on weekdays and the situation of holidays may be similar,
Instead of distinguishing between holidays and weekdays, the distinction may be made simply based on the time zone.

Next, a method of searching for a path tree will be described.
In the route tree search method according to the present embodiment, one of the links constituting the network data of the route providing area is set as the departure point link, and the optimum route tree from the departure point link to all other links in the same area is determined. This is the procedure for acquiring. Specifically, the route network data stored in the network memory is read and moved to the work area, and the path is calculated in the work area based on the Dijkstra method or the potential method.

The Dijkstra method or the potential method means that when a path tree is calculated from the current position, a link or a node closest to the current position (hereinafter referred to as a “link”) is set as a search start link, and a link starting from the search start link. This is a method of sequentially adding the costs at the time and constructing a tree of links. The Dijkstra method is
When constructing a tree of links starting from a search start link, when a link branches into a plurality of links, the path cost of each branch link (total sum of costs from the search start link to the link) A method is used in which the magnitudes are compared, rearranged in ascending order of the route cost, and searching is continued from the link having the smallest route cost.

On the other hand, in the potential method, when a certain link branches into a plurality of links, all links are treated equally without comparing the path costs of the links of each branch, and are registered first. The method is to continue searching from the link of the branch that is located. In the Dijkstra method, the link must be rearranged in the order of smaller path cost every time a search is performed. Therefore, the calculation time is spent on it. On the other hand, in the potential method, the process of rearranging the link is unnecessary, so the calculation time is reduced. Is short. In the embodiment, the potential method is adopted.

FIG. 1 shows an example of calculating a path tree. (a) is the original map, (b) (c) is an example of each route tree when departure from one point. In the route tree in (b), traffic jam occurred at the time,
An alternate route has occurred. In the route tree of (c), since the time is vacant, no detour route has occurred. Therefore, it can be seen that the form of the path tree changes according to time.

Next, a certain number of path trees having different times are selected from the reference path trees in the database 140, and are set as one group (referred to as "individual"). In this embodiment, it is assumed that eight route trees are registered for one individual. The number of individuals to be set is not one, but a plurality. The reason for making this individual may be to use all the reference path trees to calculate the shortest path, but if the number of trees is large, it takes processing time, and it also burdens the memory capacity of road beacons Therefore, the number of processing trees is reduced.

Further, if the route is fixed to one route tree at that time, it is inconvenient when traffic conditions are largely changed due to an accident, traffic congestion, weather condition, earthquake, marathon race, etc., so that it becomes another candidate. This is because the route can be presented. The reason why a plurality of individuals are selected is that a plurality of individuals to be intersections (parents) are required because an intersection operation is performed as described later.

Next, a method for evaluating an individual will be described. Because it is complicated when you consider the entire path tree, for simplicity,
Consider a case where there is one destination and there are a plurality of routes to this destination. The simplest method is to select the path cost in ascending order, but since the time is different, comparing the path costs is not logical in itself. The following problems actually occur. In the morning rush hour (time j), it takes time to go from one departure point to one destination. Among them, the route T _j that has a relatively short time
Is selected in preference to the other routes T _1j , T _2j , ‥‥. However, in a vacant time zone, the route _Tj is a relatively detour route, and the other routes _T1j and _T2j may be routes closer in temporal distance. Such an example can be imagined, for example, considering a path that crosses a railroad crossing during a rush hour in the morning. If the path costs are selected in ascending order as described above, the shortest path T _{j at the} time _j is excluded, and other paths T _1j , T _2j , ‥‥ are selected.

Next, the discussion of the path tree is extended. First, eight trees are completely randomly selected from a large number of reference path trees having a common departure place, and are set as one individual. Several such individuals are created (for example, 100 individuals). Then, the evaluation function P of each individual is defined as follows. P = E _{j, k} [min (i∈A) ｛T _ij (k) -T _jj (k)｝] (1) The meanings of the symbols in the expression (1) are as follows.

K: Identification number of the destination (all destinations in the route providing area). T _jj (k): the cost of passing the optimal route at time j to destination k at time j. T _ij (k): Time required when the optimal route at time i with respect to destination k is passed at time j. Always T _ij (k) ≧ T _jj
(K) holds.

A: A set of prepared path trees (a path tree is created for each time, and may be called a set of times). For example, in the above-described example, it is a set of eight elements. min (i∈A): operation to select the smallest of A. E _{j, k} : An operation for averaging all destinations k and time j. In the above example, there are 25 types of j and k is thousands.

The subtraction ｛T _ij (k) -T _jj in the equation (1)
(K)｝ finds the path cost error of each path tree when the departure time is changed. A value obtained by averaging this over the range of the time j and the destination k is considered to be an appropriate evaluation value for the individual in the path tree. next,
The replacement of elements (path trees) between individuals will be specifically described with reference to Table 1.

[0050]

[Table 1]

Numbers 1, 2,..., 25 in the uppermost column of Table 1
Indicates j (the number of the time when the path tree was calculated). Since this time corresponds to the reference path tree at that time on a one-to-one basis, the time number is hereinafter referred to as the reference path tree number unless otherwise specified. G1, G2,... In the left column indicate individual names. "1" in the table indicates that the reference path tree was selected as an element of the individual, and "0" indicates that the reference path tree was not selected as an element of the individual.

The first row G1 in the table shows that, as a result of completely randomly selecting eight path trees from the 25 path trees, the selected path tree numbers are 1, 4, 5, 6,.
23 and 24. The next row G2 is 2
As a result of completely randomly selecting eight path trees from among the five path trees, the selected path tree numbers are 1, 3,
6, ‥‥, 22, 25.

By repeating the above operation, 100 individuals G1
From G100, and calculate the evaluation functions P1 to P100. Next, individuals having a small evaluation function are extracted at a frequency inversely proportional to the evaluation function, and some of the elements intersect between the two individuals. As a method of crossing, for example, as shown in FIG. 5, there is a method of exchanging the first half of the individual (a) with the first half of the individual (b) (one-point crossing), but is not limited thereto. Various methods well known for algorithms (GA) can be employed. As a result of crossing,
Although the number of elements of an individual may fluctuate, in this case, the position of the crossing point is appropriately set so that the number of elements of the individual does not fluctuate. Alternatively, two or more intersections are set and intersected (two-point intersection).

As described above, the route tree rearrangement operation is performed mainly on individuals having a small evaluation function to eliminate the bias of the route cost of the route tree, to select a suitable route tree as the candidate route tree, and to select the shortest route. Is to be able to calculate efficiently. This operation is similar to the operation of gene recombination. That is, the individuals G1, G
2, G3 ‥‥ is an individual, a combination of paths constituting the individual is genetic information, and the reciprocal of the evaluation function is the adaptability of the individual. Retrieving an individual with a small evaluation function at a frequency inversely proportional to the evaluation function is equivalent to selecting, from the population, those with excellent adaptability as parents. This means that individuals are married and their generations are changed.

In this way, individuals belonging to the next generation with a smaller evaluation function are created. In the embodiment, 100 individuals are obtained for each generation. By performing the same operation for the new generation, an individual having a smaller evaluation function can be obtained. At this time, a mutation operation of changing an arbitrary element from 0 to 1 and changing other arbitrary elements from 1 to 0 may be performed on the generated individual. If the selection of the first 100 individuals is poor,
If only the evaluation function is large, an excellent individual with a small evaluation function cannot be obtained even if convergence is performed by repeating generation alternation. So, when you mutate, by accident,
Small evaluation functions may get in. Then, by crossing small evaluation functions, it can be expected that the overall evaluation function is reduced. Even if a large evaluation function enters by mutation,
There is no problem because it is eliminated immediately.

By repeating the above operations, the evaluation function converges (Skimata theorem). That is, the faces of the path trees, which are the elements of each individual, almost coincide with each other. If the ratio between the average evaluation function of the nth generation and the average evaluation function of the (n + 1) th generation is about 0.01%,
The processing is terminated to obtain a final individual.

When the route calculation conditions are different and the departure place is different, the generation change is repeated in the same manner to produce a final individual. Actually, when I calculated,
It looks like this: 2573 for the central area of Tokyo, with the link near Kasumigaseki in Tokyo as the departure point link
For the link of the book, cost information was collected every 10 minutes on a certain day. Then, each path tree is created, and 8
One hundred individual trees composed of one path tree were prepared, and the path tree was rearranged. The number of generations processed until convergence was about 150. The processing time per generation was 2 to 3 minutes in the experimental program of the embodiment, so it took 5 to 7.5 hours per departure place. Therefore, if the individual is selected based on the processing result of the neighboring link in the intended setting, the number of convergences is drastically reduced, so that it is possible to reduce the number of convergences.

The contents of the route trees belonging to individuals having common departure points and different path calculation conditions, determined by the above method, are transmitted to the beacon in charge of the departure point (the intersection at the departure point) through the communication line L. Beacon). In the road beacon C, when route data is received from the traffic control center B via the communication line L and the modem 210, the contents of the route tree (for example, FIG. 1 (b)) are stored in a memory (not shown) in the control device 220. ) (link sequence shown in (c)) is stored. <Online processing> Controller 12 of traffic control center B
0 corresponds to all on-road beacons C (the starting point is also determined if the beacon is determined) at a predetermined time (every time the latest road traffic information enters the traffic control center B; for example, every 5 minutes). To find a registered individual corresponding to the route calculation condition at the time. Now, paying attention to one road beacon C, since one individual is determined, the cost in the latest road traffic information entering the traffic control center B at that time is applied to each of eight route trees constituting this individual. Then, the route is traced for all the destinations in the route tree, the route cost (travel time) is calculated, the route costs of the routes of the same destination are compared, and the shortest route tree is selected.

In this calculation, once one destination is determined, link costs are simply added along eight routes obtained for eight route trees, and only the shortest one is selected. Can be done. The same processing is performed for other destinations. Then, for each destination, the number of the route tree that realizes the route with the shortest cost or the number of the route tree that realizes the route cost of the second, third, etc., which is not the shortest cost, on the road corresponding to the departure place Send to beacon C. To put it in analogy, "If you go to the destination a from the street beacon C, use this route tree 1""If you go to the destination b from the street beacon C, use this route tree 3 or 5" Is equivalent to sending an instruction.

Further, the same arithmetic processing is performed on the departure place corresponding to another road beacon, and the number of the path tree is transmitted. Thereby, the road beacon C can always know the route tree suitable for the current traffic condition. Since the transmission of the identification number from the traffic control center B is performed at a predetermined time, from the road beacon C, it is necessary to always know the latest route tree updated at the predetermined time. become.

In the road beacon C, when the destination is indicated by the vehicle, the route to the destination is traced by referring to the route tree of the number corresponding to the transmitted destination, and this is provided to the vehicle. Since this is the shortest route to be performed, information on this route may be sent to the vehicle. For this reason, the road beacon C communicates with the traffic control center B every time the vehicle indicates the destination, without having to do the unrealistic thing which cannot be considered normally. The route can be shown to the vehicle within the two-way communication time (usually several tens of msec).

In the above embodiment, the traffic control center B traces the route to all the destinations in the route tree, calculates the route cost (travel time), and calculates the route cost between the routes. They chose the "shortest" path tree for each destination. However, the present invention is not limited to this. Since the cost of each link making up the eight path trees is all known, the controller 120
Compares these link costs with the cost of each link at a “predetermined time” (ie, the current real-time link cost), and calculates the current real-time link cost cost distribution and cost distribution based on the following equation: _May be calculated to find the smallest path tree of the difference X _j .

X _j = _{ | (link cost of route tree j) − (current link cost) | (sum is taken for all links (destinations).) According to this method, all destinations Since a single path tree is obtained for all destinations instead of the same number of path trees, only one identification number needs to be sent to the road beacon C. Therefore, the amount of transmission information decreases.

The above equation may be modified and used as follows.

[0065]

(Equation 1)

In this equation, since the link cost of the tree is divided by the average link cost of all the links of the tree, even if the link costs of the tree all change at the same rate, this change can be absorbed. In addition, the cost distribution of the path tree can be accurately evaluated. <Summary> As described above, in the traffic control center B, the time-consuming creation of the reference route tree according to the route calculation conditions based on the past road traffic conditions, the discovery of the optimum individual, and the route tree information constituting the individual Is transmitted off-line to a beacon C, and at each predetermined time, the path is traced only by the path tree in the optimum individual to find a path tree that realizes the shortest path, and its number is sent to the road beacon C. All you have to do is work.

In the road beacon C, it is only necessary to trace the route to the destination by referring to the route tree of the transmitted number and the destination transmitted from the vehicle. As a result, the shortest route can be promptly shown to the vehicle. <Modifications> The contents of the present invention are not limited to the above embodiments.

For example, in the above embodiment, 100 individuals in which a fixed number of path trees are randomly arranged are selected as initial setting individuals for repeating generation alternation operations.
If an individual whose evaluation function seems to be as small as possible is known from the beginning, if this individual is included in the initial setting group, it is expected that convergence will be extremely fast. Then
Speaking of how such individuals can be selected, individuals are composed of path trees with the same path calculation conditions as the path calculation conditions of each path tree of the final individual obtained at the nearby departure point, You only have to be in the default group.

In the above embodiment, an individual consisting of 8 path trees is finally selected from the 25 reference path trees at different times, but the actual number of reference path trees is Usually there are many. For example, if the reference path tree every 5 minutes is stored for one day, 12 × 2
4 = 288 reference path trees. When it is not possible to select the optimum 8 path trees from the 288 reference path trees due to the limitation of the capacity of the computer to be used, first, 24 hours are divided into 2 sets every 2 hours and divided into 12 sets.
Perform the above processing in each set to obtain 12 optimal individuals. Again, the 96 path trees that make up these individuals are divided into four sets, and the best individual in each set is obtained. Finally, if the optimum individuals are obtained for the 32 route trees constituting the four optimal individuals, no burden is imposed on the computer.

[0070]

As described above, according to the first or twelfth aspect of the present invention, a route tree is created according to route calculation conditions based on various road traffic conditions, and a group including a fixed number of route trees is created. Make multiple, define the evaluation function of the group, rearrange the path tree that composes each group, and select and sort the groups so that they converge to the group that shows the preferable evaluation function, so this final group If the link cost is calculated using the current route calculation conditions for each of the included route trees, one or more route trees that best match the current route calculation conditions can be selected. . Therefore,
When a route calculation is requested, the optimum route can be indicated by using the one or a plurality of route trees without particularly complicated calculation.

According to the second aspect of the present invention, the starting point of the route tree is extended to all points in the route providing area. Therefore, it is possible to respond to a request for providing route information by indicating a destination from an arbitrary point. Claim 3
According to the invention described above, when the route tree is initialized, the route tree is obtained based on the route calculation conditions at the past time, so that the process of obtaining the route tree is simplified, and the road traffic conditions that change every moment are directly reflected. A path tree can be determined.

According to the fourth aspect of the present invention, since the path calculation condition is obtained on the average in the past period, it is possible to prevent the appearance of a unique path tree due to a sudden change. According to the invention described in claim 5, for each combination of the route calculation conditions in the past fixed period, a corresponding route tree is obtained and registered in the database, so that a route tree closer to the request route calculation condition is used. We can provide an accurate route.

According to the sixth aspect of the present invention, the convergence is accelerated and the processing time is shortened by using the route calculation condition of the group finally registered corresponding to the neighboring departure point. it can. According to the seventh aspect of the present invention, it is possible to appropriately evaluate each group by specifically defining the evaluation function.

According to the eighth aspect of the present invention, when partial crossover of the path trees constituting the group is performed, mutation is extracted, so that an excellent group can be expected to appear. According to the ninth aspect of the present invention, when the number of path trees is large, even if a group is set from the tree, the number of combinations is too large and processing can be performed and shortened when processing cannot be performed.

According to the tenth aspect of the invention, for each destination, the route cost to the destination is calculated and compared, and one or more route trees are selected in association with the destination. Therefore, the amount of information is increased because “one or more route trees” corresponding to the number of destinations are generated, but the optimal one or more route trees are selected for each destination. The route is more optimal.

According to the eleventh aspect of the present invention, for each route tree included in the registered group, without limiting the destination, the link cost pattern of each route tree and the road traffic condition at the time are described. Is compared with the link cost pattern based on the above, only one "one or more route trees" are generated, and the optimality of the route is slightly reduced as compared with the invention described in claim 10, but is handled. Since the information amount is reduced, the processing time can be reduced.

According to the thirteenth aspect of the present invention, it takes a long time in the traffic control center to create a route tree according to route calculation conditions based on various road traffic conditions, find an optimal group, and find a route that constitutes a group. The transmission of the tree data to the communication device is performed offline, and at a predetermined time, the path is traced only by the path tree in the group to find one or more optimum path trees, and the identification information thereof Send the work. The communication device need only trace the route to the destination with reference to the data of the route tree corresponding to the transmitted identification information. Therefore, even when information on destinations is intensively transmitted from a large number of vehicles over a wide range, it is possible to always provide optimal route information corresponding to each vehicle.

According to the fourteenth aspect, the traffic control center calculates and compares the route cost to the destination for each destination with respect to the route tree in the group, and One corresponding to the ground
One or more path trees are selected and their identification information is sent to the communication device so that the communication device can trace the optimal one or more path trees for each indicated destination to indicate the path. . Therefore, the optimality of the route is improved.

According to the invention described in claim 15, in the traffic control center, for the route tree in the group, the link cost pattern corresponding to each route tree and the time can be determined without limiting the destination. The communication device traces one or more of the indicated path trees because it compares the one or more path trees with one another and selects one or more of the path trees and sends its identification to the communication device. You can show the route. Therefore, the amount of processing calculated by the traffic control center decreases, and the amount of information to be transmitted from the traffic control center to the communication device also decreases.

[Brief description of the drawings]

FIG. 1 is a diagram showing a calculation example of a path tree, where (a) shows an original map, and (b) and (c) show path trees having different path calculation conditions.

FIG. 2 is a diagram showing a configuration in which a traffic control center B and a road beacon C are connected by a communication line L, and bidirectional communication by light or radio waves is performed between the road beacon C and a vehicle.

FIG. 3 is a diagram illustrating an example of a road map.

FIG. 4 is a diagram showing a link configuration of the road map of FIG. 3;

FIG. 5 is a diagram illustrating an example of a method of intersecting elements between individuals.

[Explanation of symbols]

 C Roadside beacon B Traffic control center 110 Map dedicated memory 120 Controller 130 Modem 140 Database 210 Modem 220 Controller 230 Transceiver

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01C 21/00 G08G 1/0969

Claims (15)

(57) [Claims] (A) A route tree extending from a departure point in a route providing area is calculated in accordance with a plurality of route calculation conditions based on various road traffic conditions and stored in a database. A plurality of combinations of a certain number of path trees are initially set from the path tree and stored as a group. (B2) An evaluation function P of each group is calculated. (B3) A preferable evaluation function P of each group is calculated. For some groups having, the path trees constituting the groups are partially crossed so that the evaluation function P changes in a more preferable direction. (B4) The procedure of (b2) and (b3) is performed as follows. A group finally obtained as a result of repeating the evaluation function P a plurality of times until the convergence is substantially concluded is registered. (D) For each predetermined time, each path tree included in the registered group is registered. Calculating the link cost obtained according to the route calculation conditions based on the road traffic conditions at the time, and selecting one or a plurality of route trees, and (e) providing route information by indicating at least the destination A route information providing method that indicates a route to the destination based on the one or more route trees when the request is made. 2. A route tree extending from each departure point in the route providing area is calculated in accordance with a plurality of route calculation conditions based on various road traffic conditions, and stored in a database. A departure point in an area is set, a plurality of combinations of a fixed number of path trees are initially set from a path tree in the database starting from the departure point and stored as a group, and (b2) evaluation of each group Calculate the function P. (b3) For each of the groups having the preferable evaluation function P among the groups, one of the path trees constituting the group is changed so that the evaluation function P changes in a more preferable direction. (B4) The procedure of (b2) and (b3) is repeated a plurality of times until the evaluation function P substantially converges, and the finally obtained group is registered. (C) Route providing area It is in For other departure points,
(b1) to (b4) are repeated to create and register a group of path trees, and (d) for each predetermined time, for each path tree included in the registered group, the time The link cost obtained in accordance with the route calculation conditions based on the road traffic conditions of (i) is calculated and one or more route trees are selected, and (e) at least the destination is indicated and a request for providing route information is made. When there is a route information providing method, a route to the destination is indicated based on the one or more route trees. 3. The route information providing method according to claim 1, wherein the "a plurality of route calculation conditions based on various road traffic conditions" in the step (a) refer to route calculation conditions at a plurality of past time points. . 4. The step (a) of “a plurality of route calculation conditions based on various road traffic conditions” refers to route calculation conditions averaged over a plurality of past periods, respectively.
Or the route information providing method according to 2. 5. The method according to claim 1, wherein in the step (a),
For each one or a combination of month, season, day of the week, weekday / holiday, time zone, presence / absence of an event, presence / absence of an accident, a corresponding route tree is obtained and stored in a database. 3. The route information providing method according to 1 or 2. 6. A method of initializing a group in the step (b1) is to set a group of path trees corresponding to a path calculation condition of each path tree of a group finally registered corresponding to a neighboring departure point. 3. The route information providing method according to claim 1, wherein the initial setting is performed. 7. The calculation of the evaluation function P in the step (b2) is performed by the following equation: P = E _{j, k} [min (i∈G) ｛T _ij (k) -T _jj (k)｝] (T _jj (K): the route cost of the optimal route to the destination k obtained by the route tree j T _ij (k): the optimal route to the destination k obtained by the route tree i passes below the route tree j Min (i∈G): operation to select the smallest one among groups E _{j, k} : average of all route trees j and all destinations k And the evaluation function P becomes more preferable when P
The route information providing method according to claim 1, wherein the route information becomes smaller. 8. The route information providing method according to claim 1, wherein the constituent route tree is deliberately changed when partially intersecting the route trees constituting the group in the step (b3). 9. When initializing a plurality of combinations of path trees from the path tree in the database in the step (b1), the path tree is not set for all the corresponding path trees in the database but is set. Classify and perform the operations (b1) to (b4) for each classification to select a group, and for the path tree that constitutes the selected group, (b1)
3. The route information providing method according to claim 1, wherein a group is finally obtained by performing steps (b4) to (b4). 10. In the step (d), for each predetermined time, for each destination, for each route tree included in the registered group, a route calculation condition based on a road traffic condition at the time. Calculate and compare the route cost to the destination obtained according to the above, select one or a plurality of route trees, associate the route tree with the destination, and in the step (e), Requesting a route information at least by indicating the destination, indicating a route to the destination based on one or more route trees associated with the destination; Item 6. The route information providing method according to item 1 or 2. 11. In the step (d), for each route tree included in the registered group at a predetermined time, the destination of the link cost corresponding to each route tree can be determined without limiting the destination. The pattern and the link cost pattern based on the road traffic conditions at the time are compared, and any one or a plurality of route trees are selected, and in the step (e), at least the destination is indicated by indicating the route information. 3. The route information providing method according to claim 1, wherein a route to the destination is indicated based on the one or more route trees when a provision request is made. 12. A database for calculating and storing route trees extending from a departure point in a route providing area in accordance with a plurality of route calculation conditions based on various road traffic conditions, and a fixed number of route trees from the database. (B1) to (b4) of claim 1 or (b) of claim 2
(1) to (b4) and (c), a registration means for obtaining and registering the registered group, and searching for the registered group at predetermined times, and for each path tree included in the group, Storage means for calculating link costs obtained in accordance with a route calculation condition based on road traffic conditions at the time, selecting one or a plurality of route trees, and storing identification information of the route trees; And a route selecting means for selecting a route to the destination based on one or more route trees corresponding to the stored identification information when a request for providing route information is given. A route information providing device. 13. A traffic control center, a communication device disposed at various points in a road traffic network for two-way communication with vehicles, and a communication line connecting the traffic control center and the communication device, wherein the traffic control center provides a route. A database for calculating and storing route trees extended from each departure point in the area according to a plurality of route calculation conditions based on various road traffic conditions, and a group of route trees in the database.
Registering means for obtaining and registering by the procedures of (b1) to (b4), and first transmitting means for transmitting data of a path tree included in the group registered by the registering means to the communication device; At each time, the registered group is searched, and for each of the route trees included in the group, a link cost obtained according to a route calculation condition based on the road traffic condition at the time is calculated, and any one of the link costs is calculated. Or a second transmission unit that selects a plurality of path trees and transmits the identification information to the communication device, wherein the communication device stores the data of the path tree transmitted from the first transmission unit. Based on one or more route tree data corresponding to the identification information transmitted from the second transmitting means, one or more of the route to the destination where the route information provision request was made from the vehicle. Route information providing system having a route selection means for selecting a number of routes. 14. The second transmitting means of the traffic control center searches the registered group for each predetermined time and for each destination, and searches the route tree included in the group for the time. The route cost to the destination obtained according to the route calculation condition based on the road traffic condition is calculated and compared.
And selecting one or a plurality of route trees and transmitting the identification information to the communication device. Claims for selecting one or more routes to a destination to be indicated to a vehicle based on data of one or more route trees corresponding to identification information corresponding to a destination requested to be provided. Item 14. The route information providing system according to Item 13. 15. The second transmitting means of the traffic control center retrieves the registered group at predetermined times, without limiting a destination for each route tree included in the group. Comparing the link cost pattern corresponding to each route tree with the link cost pattern based on the road traffic condition at the time, selecting one or a plurality of route trees, and transmitting the identification information to the communication device. The route selection means of the communication device, from the vehicle based on one or more route tree data corresponding to the identification information among the identification information transmitted from the second transmission means, 14. The route information providing system according to claim 13, wherein one or a plurality of routes to the destination requested to provide the route information are selected.