JPH05164564A - Vehicle guidance device - Google Patents

Abstract

PURPOSE:To properly and surely search a route of a start point to goal by newly setting the node of a temporary start point or a temporary goal at a point on a line segment where a perpendicular drawn up to the line segment between nodes is the shortest. CONSTITUTION:The number of pulses from a distance sensor 1 is counted to measure the distance that a vehicle has run, and the change in the distance is deduced from the output signal of a direction sensor for the purpose of the finding of the present position on an X-Y coordinate at regular intervals of distance. The whole control is performed by the use of a signal processor 3 composed of a microcomputer. When a route of a start point to a goal set on a road map based on digital map data is searched from node pursuit, the node of an temporary start point to a temporary goal is newly set at a point on a line segment, in which a perpendicular drawn up to the line segment between the nodes on a road from the start point or the goal set except for the road on the map is the shortest, for the purpose of route search.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel guide device for searching a route from a starting point set on a road map displayed on a screen to a destination and providing vehicle travel guidance. ..

[0002]

2. Description of the Related Art Recently, a starting point and a destination are arbitrarily set on a road map displayed on a screen, and an optimum route from the set starting point to the destination is set based on digital map data. Has been developed, and a vehicle travel guide device has been developed which guides the travel of the vehicle in accordance with the searched route (for example, JP-A-62-133).
See Japanese Patent Application Laid-Open No. 600 or Japanese Patent Application Laid-Open No. 1-173297).

As digital map data, an actual road shape shown in FIG. 3 is approximated to a polygonal line by a line segment as shown in FIG. It consists of data on the connection status between the two.

Conventionally, in order to perform a route search based on digital map data, for example, in the case of performing a shortest route search from a starting point to a destination according to a known algorithm such as Dijkstra method, It will follow the connected nodes on the digital map one after another so that the required distance will be the shortest,
When the starting point or the destination is set outside the road on the map, the node of the starting point or the destination cannot be specified, and the route search cannot be performed.

[0005]

The problem to be solved is to search a route from a starting point set on a road map to a destination by node tracking based on digital map data, When the starting point or the destination is set outside the road on the map, the node of the starting point or the destination cannot be specified and the route search cannot be performed.

At this time, a node closest to the starting point or destination set outside the road on the map is selected and set as a temporary starting point or destination node so that the route search is performed. Then, for example, as shown in FIG.
The direction of the temporary starting point S ′ on the road viewed from the starting point S may be opposite to the direction of the destination O, and the route to be searched becomes a large route to efficiently guide the vehicle. You will not be able to do it.

Further, as shown in FIG. 6, the direction of the destination O viewed from the starting point S set outside the road on the map is taken into consideration, and the most within the range of a predetermined angle α in that direction. It is conceivable to select a close node and set it as a temporary starting point S ′ node so as to perform a route search. However, even in that case, a large route is still searched. As a result, the provisional starting point S'is set inappropriately.

Further, it is conceivable that a plurality of temporary starting points or destinations are set so that the optimum route can be selected from the routes searched for each candidate. Has a problem that the processing for route search is required for the number of candidates and the processing time becomes long.

[0009]

According to the present invention, when a route from a starting point set on a road map to a destination is searched by a node tracking based on digital map data, an optimum route is found. To enable the search, a temporary starting point or destination is set to the point on the line segment where the perpendicular line from the starting point or destination set outside the road on the map to the line segment between the nodes on the road becomes the shortest. The ground node is newly set so that the route can be searched.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of a vehicle traveling guide device according to the present invention. For example, a distance sensor 1 for outputting a pulse signal for each unit traveling distance according to the rotation of a tire of a vehicle.
For example, a directional sensor 2 that outputs a signal proportional to the amount of directional change that accompanies traveling of the vehicle that detects a change in angular velocity in the yaw direction, and the number of pulse signals from the distance sensor 1 is counted to measure the traveling distance of the vehicle. At the same time, the current position on the XY coordinates for each constant traveling distance of the vehicle is sequentially calculated by calculating the change in the traveling direction according to the output signal of the direction sensor 2, and the entire vehicle traveling guide device is obtained. A signal processing device 3 including a microcomputer for performing control, and data of the current position of the position on the XY coordinates that is obtained by the signal processing device 3 and changes every moment are sequentially stored, and finite continuous position information of the vehicle is stored. And a map information storage medium in which road map information based on digital map data is stored in advance. 5, a storage medium reproducing device 6 for selectively reading out road map information of a required area from the storage medium 5, a predetermined road map is displayed on the screen based on the read road map information, and the screen is displayed. A display device 7 for displaying the current position of the vehicle on the road map shown in FIG. 2 along with the traveling locus and the traveling direction of the vehicle at the current position as necessary as the vehicle travels, and a signal processing device. 3 is given an operation command, the map is displayed on the display device 7, and the starting point and destination of the vehicle are set on the displayed map. Change the direction of the displayed map and travel path,
The operation unit 8 is capable of appropriately changing the display position such as shifting of the display position, partial enlargement display of the map and traveling locus, selection of display scale factor, and the like.

With the above-described structure, the selectively read road map is displayed on the screen of the display device 7, and signal processing is performed in accordance with the traveling of the vehicle from the starting point set on the map. The current position on the XY coordinates is calculated by the device 3 every moment in accordance with the preset scale of the map, and the calculation result is sequentially sent to the traveling locus storage device 4 to update the stored contents. As it goes, the stored contents are read and sent to the display device 7.

As a result, the display device 7, for example, as shown in FIG.
As shown in FIG. 1, a display mark M1 indicating the current position of the vehicle on the map displayed on the screen, a display mark M2 indicating the traveling direction of the vehicle at the current position, and a traveling locus from the starting point S to the current position. The display mark M3 is displayed in a simulated manner following the running state of the vehicle.

According to the present invention, there is provided such a vehicle guide device, in which the signal processing device 3 sets the departure set on the road map displayed on the screen based on the digital map data read from the map information storage medium 5. The route from the point to the destination is searched by node tracking, and the optimal route is determined in consideration of road information such as required distance and one-way traffic.For example, the optimal route on the road map displayed on the screen is specified. By using a different color, it is possible to guide the vehicle so that the current position of the vehicle is updated and displayed on the optimum route.

Here, various known methods are widely applied to the basic algorithm of the route search and the determination of the optimum route itself.

In such a case, particularly in the present invention, when the departure point S is set outside the road on the map as shown in FIG. 7, each node N on the road near the departure point S is set. A perpendicular line is drawn on each line segment between the lines, and a means for newly setting a temporary starting point node at the point S'on the line segment where the perpendicular line is the shortest is taken, and the new node is set as the start point of the node tracing. The feature is that a route search is performed as.

Normally, as the digital map data, as shown in Table 1 below, a table of data on each node, that is, a table of data on the position on the XY coordinates of each node, the number of branches, and a branch destination node is created. There is.

[0017]

Then, the route search by the node tracking is equivalent to performing the route search by listing each node on the route from the starting point to the destination using the table.

Therefore, the data regarding the node newly set as the temporary starting point S'on the line segment between the nodes,
For example, node number 0, coordinate position (19, 38), branch number 2, branch destination node (1, 2) are added to the table while matching with other nodes, and the new data is added. A route search by node tracking will be performed using the created table.

Even when a destination is set outside the road on the map, the perpendicular line on the line segment between the nodes on the road from the destination is the shortest on the line segment. A node of a temporary destination is newly set at the point and a route search is performed.

Further, even when the starting point or the destination is set at the position on the line segment between the nodes on the road on the map, a new node is set at the position and the route is set as described above. A search may be performed.

As described above, according to the present invention, even when a starting point or a destination is set outside the road on the map, it is possible to perform a route search in which a large route is not searched. It becomes possible to reset the provisional starting point or destination to the optimum position on the road and optimally perform the route search.

Further, according to the present invention, a preprocessing for setting a temporary starting point or a destination node between nodes on a road can be performed without performing a route search by node tracking using any special algorithm. The route search from the starting point to the destination can be surely performed only by performing the process.

[0024]

As described above, in the vehicle travel guide device according to the present invention, the perpendicular line drawn from the starting point or the destination set outside the road on the map to the line segment between the nodes on the road becomes the shortest. Since a temporary start point or destination node is newly set at a point on the line segment to perform route search by node tracking, the route from the start point to the destination can be optimally and reliably It has the advantage of being searchable.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a vehicle travel guide device according to the present invention.

FIG. 2 is a diagram showing an example of display contents in the embodiment.

FIG. 3 is a diagram showing an example of an actual road shape.

4 is a diagram showing a digital map of the road of FIG.

FIG. 5 is a diagram showing an example of a digital map when a tentative departure point is set to a node closest to a departure point set outside the road on the map.

FIG. 6 is a diagram showing an example of a digital map when a tentative departure point is set to a node closest to a departure point set outside the road on the map in consideration of the direction of the destination.

[Fig. 7] When a node of a temporary starting point is newly set at a point on a line segment where the perpendicular line drawn from the starting point set outside the road on the map to the line segment between nodes on the road is the shortest It is a figure which shows an example of the digital map of.

[Explanation of symbols]

 1 distance sensor 2 direction sensor 3 signal processing device 4 traveling locus storage device 5 map information storage medium 6 storage medium reproducing device 7 display device 8 operating device

Claims (2)

[Claims] 1. A departure set on a road map displayed on a screen based on digital map data composed of data on nodes at end points and connection points of each line segment when an actual road shape is approximated by a polygonal line. In a vehicle travel guidance device that guides the travel of a vehicle by tracking a node on a route from a point to a destination, a starting point or a destination set outside the road on the map A vehicle characterized by adopting means for newly setting a temporary starting point or a destination node at a point on a line segment where the perpendicular line drawn from the ground to the line segment between nodes on the road is the shortest Driving guidance device. 2. A route search is performed by creating a table of data relating to each node in the digital map data, and using the table to list each node on the route from the starting point to the destination. The vehicle travel guide device according to the above-mentioned item 1, characterized in that means is added to the table and data regarding a temporary starting point or a destination node is added to the table.