JP2929924B2 - Route guidance device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle route guidance apparatus for searching for a route from a current position to a destination, finding an optimum route, and guiding a vehicle to a destination according to the optimum route.

[0002]

2. Description of the Related Art There is known a vehicular route guidance device that searches for a route from a current position of a vehicle to a destination to obtain an optimum route, and displays the optimum route and the current position of the vehicle on a display. Further, Japanese Patent Application Laid-Open No. 2-277200 discloses an apparatus for performing a route search by a known Dijkstra method or the like after setting various route search conditions desired by an occupant.
As the route search conditions, a route with the shortest time to the destination, a route with the shortest distance to the destination, a route with the least cost to the destination, a route with the least number of right and left turns to the destination, etc. are set. can do.

[0003]

When a vehicle makes a right or left turn at an intersection, the signal interval for a right turn is often shorter than that of a left turn. Therefore, in general, it takes more time for a right turn to pass through an intersection than for a left turn. It takes. Therefore, when performing a route search, it is desirable to perform calculations while distinguishing straight ahead, right turn and left turn at an intersection. For this reason, in the above publication, the route search is performed by multiplying the time coefficient of right turn and the time coefficient of left turn by the total number of right turns and the total number of left turns, respectively.

[0004] However, the time required to make a right turn differs between a right turn from a general road to a national road and a right turn from a general road to a general road, for example. Therefore, when estimating the intersection passing time at the time of turning right and left, it is necessary to take into account the road type before turning right and left and the road type after turning right and left. In this regard, in the above-mentioned publication, the intersection passing time is predicted only by the number of right / left turns and the right / left turn time coefficient, and cannot be correctly predicted.

[0005] Further, as the number of roads connected to the intersection increases, the signal interval becomes shorter, and the time allowed to travel on each road is limited, so that the intersection passage time becomes longer. Therefore,
It is desirable to perform a route search in consideration of the number of connected roads.

SUMMARY OF THE INVENTION An object of the present invention is to provide a route guidance device for a vehicle which performs a route search after predicting an intersection passing time based on a right / left turn at an intersection, a change in road type at the intersection, and the number of connecting roads at the intersection. To provide.

[0007]

The present invention will be described with reference to FIG. 1 showing an embodiment. The present invention provides a road map storage means 3 for storing road map data including intersection information, and a current position of a vehicle. Vehicle position detecting means 1 and 2 for detecting, a destination setting means 7 for setting a destination, a route searching means 4 for performing a route search from the current position to the destination based on the road map data to obtain an optimum route, The present invention is applied to a vehicle route guidance device having display means 9 for displaying a route, and depending on the angle between the approach road to the intersection and the exit road from the intersection, the vehicle goes straight, turns right or turns at the intersection. Right / left turn determining means 4 for determining a left turn, road type difference detecting means 4 for detecting a difference between a road type of an approach road and a road type of an outgoing road, determination results by right / left turn determining means 4, and road type difference detection By means 4 Based on the detected difference, intersection passage time predicting means 4 for predicting the intersection passage time of the vehicle
The above object is achieved by configuring the route search means 4 so as to obtain the optimal route from the current position to the destination based on the predicted intersection passing time. According to a second aspect of the present invention, there is provided the vehicle route guidance apparatus according to the first aspect, further comprising a connecting road number measuring unit 4 for measuring the number of roads connected to the intersection for each intersection. The intersection passage time prediction means 4 is configured to predict that the intersection passage time is longer as the number of roads is larger.

[0008]

According to the first aspect of the present invention, right / left turn determining means 4 is provided.
The straight-line, right-turn or left-turn of the vehicle at the intersection is determined by the road type difference detecting means 4, and the difference between the road type of the approach road at the intersection and the road type of the exit road is detected by the road type difference detecting means 4. And road type difference detecting means 4
The intersection passage time is predicted by the intersection passage time prediction means 4 based on the difference detected by the intersection. Then, the route search means 4 obtains the optimum route from the current position to the destination based on the predicted intersection passing time, so that the accuracy of the calculated optimum route is improved. According to the second aspect of the present invention, as the number of roads connected to each intersection measured by the connecting road number measuring means 4 increases, the intersection passing time prediction means 4 predicts that the intersection passing time will be long.

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

[0010]

FIG. 1 is a block diagram showing an embodiment of a vehicle route guidance apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an azimuth sensor, which detects a traveling azimuth of a vehicle by detecting, for example, geomagnetism at a position where the vehicle exists. Reference numeral 2 denotes a vehicle speed sensor which is attached to, for example, a transmission of the vehicle and outputs a predetermined number of pulse signals according to the vehicle speed. Reference numeral 3 denotes a map storage memory for storing road map data including intersection network data, including road type information such as expressways and national roads, intersection connection road information, intersection distance information, and the like.
Character information such as road width information and place names are stored.

Reference numeral 4 denotes a C for calculating the shortest time route from the current position to the destination by performing the processing of FIGS.
PU. Reference numeral 5 denotes a ROM for storing a control program executed by the CPU 4 and the like, and reference numeral 6 denotes a RAM for storing a calculation result by the CPU 4. Reference numeral 7 denotes an operation board for inputting a destination of the vehicle, and 8 denotes a V-RAM for storing image data generated by the CPU 4. The data stored in the V-RAM 8 is displayed on a display 9. Direction sensor 1, vehicle speed sensor 2, map storage memory 3, CP
U4, ROM5, RAM6, operation board 7, V-RAM
Both the display 8 and the display 9 are interconnected via an interface circuit 10.

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

Next, the CPU 4 performs the processing shown in FIGS. 2 to 4 to predict an intersection passing time at each intersection. In step S1 of FIG. 2, the intersection information stored in the map storage memory 3 is read. In step S2, FIG.
To obtain the angle coefficient α1. This angle coefficient α
1 is a coefficient for distinguishing straight ahead, right turn or left turn at an intersection. In step S3, a road type coefficient α2 is obtained by the processing of FIG. 4 described later. This road type coefficient α2
Is a coefficient indicating the degree of difference in road type at the intersection. In step S4, the number of roads connected to each intersection (hereinafter referred to as
(Referred to as the number of connection roads) is determined. This α3 increases as the number of connecting roads increases. That is, the value of α3 is greater at the crossroads intersection than at the T-junction intersection, at the crossroads intersection than at the crossroads intersection. Note that α3 is a real number larger than 1.

In step S5, an intersection passage predicted time T is calculated using the coefficients obtained in steps S2 to S4. Specifically, assuming that the average transit time required to pass through the intersection is T0, the average transit time is represented by the following equation (1).

T = T0 × α1 × α2 × α3 (1) The average transit time T0 is determined based on, for example, a measured value at an actual intersection.

FIG. 3 is a flowchart showing the setting process of the angle coefficient α1 in step S2 of FIG. In step S11, an angle θ between the approach road and the exit road is determined, with one of the roads connected to each intersection as the approach road and the other one as the exit road. In step S12, it is determined whether the angle θ is equal to or more than 0 ° and less than 135 ° as shown in FIG. If the determination is affirmative, it is regarded as a right turn, and the process proceeds to step S13, where the angle coefficient α1 is calculated as α1 = 1 + K1 + K2 (where K1, K2>
0) and returns. If a negative determination is made in step S12, the process shifts to step S14, where the angle θ is 13
It is determined whether it is 5 ° or more and less than 225 °. If the determination is affirmative, it is determined that the vehicle is traveling straight, and the process proceeds to step S15, where the angle coefficient α1 is set as α1 = 1, and the process returns. If a negative determination is made in step S14, the process proceeds to step S16 assuming a left turn, and the angle coefficient α1 is calculated as α1 = 1 + K1.
And return.

As described above, the angle coefficient α1 when traveling straight at an intersection is set to “1”, and when turning left, “K”
By adding “1” and then turning right, “K2” is further added to set the angle coefficient α1 to increase in the order of straight-ahead → left-turn → right-turn.

FIG. 4 is a flowchart showing the setting process of the road type coefficient α2 in step S3 of FIG. In step S21, a road type value is set. The road type value is a coefficient value for distinguishing each type of road from the expressway, the national road, the main local road, and the general road. The expressway is “4”, the national road is “3”, and the main local road is “2”. ”, And the general road is“ 1 ”. In step S22, the absolute value difference between the road type value of the approach road and the road type of the approach road is determined, with one of the roads connected to each intersection as the approach road and the other one as the approach road. Calculate A. For example, if the approach road is a major local road and the approach road is a national road, A = | 2
-3 | = 1, and A = | 4-1 | = 3 when the approach road is a highway and the exit road is a general road.

In step S23, it is determined whether or not the road type value of the approach road is larger than the road type value of the exit road. If the determination is negative, the process moves to step S24, sets the coefficient B to B = 1, and moves to step S26. On the other hand, if the determination is affirmative in step S23, the process proceeds to step S25, and the process proceeds to step S26 as B = 1 + K3 (where K3> 0). In step S26, the process returns after calculating the road type coefficient α2 according to the equation (2).

Α2 = 1 + K4 × A × B (2)

The processing of FIG. 4 can be summarized as follows: Step S22
Quantifies the difference between the road types of the entering and exiting roads, and discriminates which of the road types of the entering and entering roads is larger in steps S23 to S24, and based on those results, the road type coefficient α2 in step S25. Ask for.

As described above, in the flowcharts of FIGS. 2 to 4, the average transit time at the intersection is weighted based on the traveling direction of the vehicle at the intersection, the degree of difference of the road type, and the number of connecting roads. Predict accurately.

When the predicted intersection passage times are calculated for all the intersections of the road map data by the processing of FIGS. 2 to 4, the CPU 4 performs a route search according to the flowcharts of FIGS. Calculate the route.

In step S101 of FIG. 6, a departure intersection is specified. This departure intersection is described in, for example, JP-A-62-86499.
As disclosed in the official gazette, from the intersection around the current location, there is outside the circle of a predetermined radius around the current location,
And the intersection closest to the current location is specified as the departure intersection. In step S102, the departure intersection is set as the center intersection, and among the intersections adjacent to the departure intersection, the intersection that is closer to the current location is set as the immediately preceding intersection. In step S103, the required time L at the departure intersection is set to 0, and the required time at all other intersections is set to a very large value +
Set to ∞. The required time L refers to the time required to go from the departure intersection to the target intersection.

In step S104, one of the intersections adjacent to the central intersection is selected. In step S105, the required time L at the center intersection, the time L0 required to go from the center intersection to the adjacent intersection, the predicted intersection passage time T at the center intersection when going from the previous intersection through the center intersection to the adjacent intersection, and To obtain a value f. In this case, the intersection passage predicted time T is shown in FIG.
The value obtained by the processing of step 4 is used. Step S106
Then, it is determined whether or not f obtained in step S105 is shorter than the required time L of the adjacent intersection. If the determination is affirmative, the process shifts to step S107 to set the required time L of the adjacent intersection to f.

Next, in step S108 of FIG. 7, it is determined whether or not the adjacent intersection is registered in the center intersection candidate list. If the determination is negative, the process proceeds to step S109, where the adjacent intersection is additionally registered in the center intersection candidate list, and the process proceeds to step S110. On the other hand, step S10
When the determination of No. 8 is affirmative, the process also proceeds to step S110, the intersection just before the adjacent intersection is set as the center intersection, and the process proceeds to step S111.

On the other hand, if the determination in step S106 is negative, the process also proceeds to step S111, and it is determined whether or not the processes in steps S104 to S110 have been performed for all adjacent intersections. If the determination is negative, step S11 is performed.
Then, the process goes to 2 to select an intersection having the shortest required time L from the center intersection candidate list and newly set the intersection as the center intersection.

In step S113, it is determined whether or not the center intersection coincides with the destination. If the determination is negative, the process moves to step S114, the center intersection selected in step S112 is deleted from the center intersection candidate list, and the process returns to step S104. Similarly, when the determination in step S111 is denied, the process returns to step S104. On the other hand, if the determination is affirmative in step S113, step S115 is performed.
Then, the shortest route from the current location to the destination is obtained by sequentially following the intersection immediately before the destination, and the result is stored in the RAM 6.

In summary of the processing of the flowcharts of FIGS. 6 and 7 described above, initial settings are performed in steps S101 to S103, and in steps S104 to S107,
Neighboring intersection (one of the intersections adjacent to the central intersection)
Is updated (the time required to go from the departure intersection to the adjacent intersection). At this time, the calculation is performed in consideration of the predicted intersection passing time T at the center intersection. In steps S108 to S110, registration to the center intersection candidate list and specification of the intersection immediately before the adjacent intersection are performed. Steps S104 to S104 for all intersections adjacent to the central intersection
After performing the processing of S110, in step S112, an intersection having the minimum required time L in the center intersection candidate list is set as the center intersection. The processes in steps S104 to S112 are repeated until the center intersection coincides with the destination. When the center intersection becomes the destination, the shortest time route is obtained in step S115.

As described above, in the flowcharts of FIGS. 6 and 7, the route search is performed by the known Dijkstra method in consideration of the predicted time of passing through the intersection at the central intersection, so that the shortest time from the current position to the destination is obtained. The route can be calculated accurately. Also, since the processing is common to the processing of the conventional apparatus except for the processing of step S105 in FIG. 6, the change of the algorithm is small.

In the above embodiment, the route search is performed by the processing of FIGS. 6 and 7 after the predicted passage times of all the intersections on the road map are calculated by the processing of FIGS. 6 and 7 are performed before the processing of FIG.
In step S <b> 106, only the predicted passage time of the symmetrical intersection may be obtained by the processing in FIGS. As a result, the operation time can be reduced. In step S12 in FIG. 3, it is determined that the vehicle is turning right when the angle between the approach road and the exit road is less than 135 °, but the angle used for this determination is not limited to 135 °. Similarly, the case of a left turn is not limited to 225 °. In FIG. 4, the road types are classified into four types: expressways, national roads, major local roads, and general roads. However, they may be classified more finely.
It may be classified into less than one.

In the above-described embodiment, the intersection passage prediction time is obtained by providing three coefficients of the angle coefficient α1, the road type coefficient α2, and the connecting road number coefficient α3. However, other coefficients may be provided. For example, a coefficient that takes into account the road width of the approaching / entering road may be provided. In the above embodiment, the shortest time route from the current position to the destination was calculated. However, the intersection passage predicted time obtained in the flowchart of FIG.
The shortest distance route from the current location to the destination may be calculated. In FIGS. 6 and 7, the Dijkstra method is used when calculating the shortest time route, but the calculation may be performed by a method other than the Dijkstra method.

In the embodiment configured as described above,
The map storage memory 3 stores the direction sensor 1
And the vehicle speed sensor 2 as the vehicle position detecting means, the operation board 7 as the destination setting means, the processing in FIGS. 6 and 7 as the route searching means, the display 9 as the display means, and the processing in FIG. 4 is performed by the road type difference detecting means.
Is performed by the intersection passing time prediction means in step S in FIG.
4 corresponds to the connecting road number measuring means.

[0032]

As described above in detail, according to the present invention, the route search is performed after predicting the intersection passing time based on the right / left turn at the intersection and the change of the road type at the intersection. The optimal route from to the destination can be calculated accurately. According to the second aspect of the present invention, since the intersection passing time is predicted in consideration of the number of connecting roads at the intersection, the accuracy of the route search is further improved.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating a calculation process of an intersection passage predicted time by a CPU;

FIG. 3 is a flowchart showing a setting process of an angle coefficient by a CPU.

FIG. 4 is a flowchart illustrating a setting process of a road type coefficient by a CPU;

FIG. 5 is a diagram illustrating an angular relationship between an intersection approach road and an exit road.

FIG. 6 is a flowchart showing a route search process by the Dijkstra method by the CPU.

FIG. 7 is a flowchart following FIG. 6;

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-129893 (JP, A) JP-A-4-372985 (JP, A) JP-A-4-280287 (JP, A) JP-A-2- 244399 (JP, A) JP-A-6-266998 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01C 21/00 G08G 1/0969

Claims (2)

(57) [Claims] 1. Road map storage means for storing road map data including intersection information; vehicle position detection means for detecting a current position of a vehicle; destination setting means for setting a destination; A route search means for performing a route search from the current position to the destination to obtain an optimum route, and a display means for displaying the optimum route, wherein a road approaching an intersection and a road exiting from the intersection are provided. Right or left turn determining means for determining whether the vehicle is going straight, turning right or turning left at the intersection according to the angle between the intersection and the road type for detecting a difference between the road type of the approach road and the road type of the exit road. An intersection for predicting an intersection passing time of a vehicle based on a difference detected by the right / left turn determining means and the difference detected by the road type difference detecting means. And a transit time prediction means, said route search means, the predicted intersection passage time vehicle navigation system, characterized in that determining the optimum route from the current position to the destination based on. 2. The route guidance device for a vehicle according to claim 1, further comprising connection road number measurement means for measuring the number of roads connected to the intersection for each intersection, wherein said intersection passage time prediction means includes: A vehicle route guidance device, which predicts that the greater the number of roads connected to the vehicle, the longer the intersection passage time.