JP2010151692A - Road shape estimation device, road shape estimation method, and road shape estimation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a road shape estimation device, a road shape estimation method, and a road shape estimation program capable of improving the accuracy of a curve relaxation zone length. <P>SOLUTION: A navigation device 2 includes a road traffic act information storage 14 storing a road construction time and a relaxation length act table 16 in association with each other. A basic relaxation section length in a processing object is calculated on the basis of road network data 11 or the like. The road construction time of the processing object section is determined, and the relaxation length act table 16 corresponding to the road construction time of the processing object is obtained. A basic relaxation zone length is corrected so that the obtained relaxation length act table 16 is satisfied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a road shape estimation device, a road shape estimation method, and a road shape estimation program.

  Recently, road information including road network information representing a road network, map information for drawing a map on a display, etc. provides driving support, information provision to drivers, information provision to other vehicles or pedestrians around the vehicle, etc. Used in advanced support systems. For example, in this system, a road shape is detected using road information, and various types of information corresponding to the support content are generated based on the detection result. Then, the generated information is transmitted to various ECUs (Electronic Control Units) mounted on the vehicle for assistance.

  As an altitude support system, for example, a system that provides support such as travel support and information provision for a curve ahead of a vehicle has been proposed. A curve is generally composed of a circular section having a constant radius of curvature, and a relaxation section provided between the circular section and a straight section continuous to the curve. The relaxation section is a section where the radius of curvature is gradually increased from the straight section to the circular section, and abrupt changes in the curvature radius between the straight section and the circular section are alleviated to make unreasonable driving operations. In addition, excessive centrifugal force is suppressed. Accordingly, among systems that provide support for curves, there is a system that acquires the length of a relaxation section and performs support based on the relaxation section length.

Since the relaxation section length is not included in the road information, it needs to be calculated based on the road information. For example, Patent Document 1 describes a system that calculates various parameters of a relaxation section based on a table in which a radius of curvature and a clothoid coefficient are associated with each other. This system obtains the minimum value of the radius of curvature of the circular section based on the road information, and acquires the clothoid coefficient corresponding to the minimum value of the radius of curvature from the table.
JP 2005-214839 A

  However, the plurality of coordinate points stored in the road information merely indicate a rough shape of the road, and the interval at which the coordinate points are set is not strictly defined. For this reason, the coordinate point may be set at a position deviating from the actual shape, or the number of coordinate points set in the curve may be small. Therefore, if the relaxation zone length is simply calculated based on the road information, it may differ from the actual relaxation zone length.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a road shape estimation device, a road shape estimation method, and a road shape estimation program capable of improving the accuracy of a curve relaxation section length. There is.

In order to solve the above-described problems, the invention according to claim 1 is directed to a structure definition storage means for storing a road construction time and a road structure specification in association with each other, and a curve section to be processed based on road information. Basic information generating means for calculating a basic relaxation section length indicating the length of the relaxation section, construction time determination means for determining the road construction time of the curve section to be processed, and the road construction time of the curve section to be processed Provision information obtaining means for obtaining the road structure provision corresponding to the above and section length correction means for correcting the basic relaxation section length so as to satisfy the obtained road structure provision.

  According to the configuration of the first aspect, the basic relaxation section length of the processing target section generated based on the road information is corrected so as to satisfy the road structure rule corresponding to the road construction time of the processing target section. For this reason, due to the error included in the road information, it is possible to correct the basic relaxation section length that is out of the road structure specification to an appropriate range in accordance with the road structure specification. For this reason, the precision of the relaxation area length in a process target area can be improved.

  According to a second aspect of the present invention, in the road shape estimation device according to the first aspect, the road structure prescription defines a relationship between a radius of curvature in a curved section of a curved section and a relaxation section length, and the processing Further comprising a radius of curvature acquisition means for acquiring a radius of curvature in a circular section of the target curve section, the section length correction means corresponds to the acquired curvature radius and the road construction time of the curve section to be processed The basic relaxation section length is corrected so as to satisfy the road structure regulations.

  According to the configuration of the second aspect, the curvature radius in the circular section of the curve section to be processed is acquired. Also, among the road structure regulations that define the relationship between the radius of curvature and the relaxation section length in a circular section, using the road structure regulations corresponding to the acquired curvature radius and the road construction time of the curve section to be processed, The relaxation section length of the process target section is corrected. For this reason, the relaxation section length in the process target section can be estimated with higher accuracy.

  According to a third aspect of the present invention, in the road shape estimation apparatus according to the second aspect, the curvature radius acquisition means calculates a curvature radius of the circular section based on the road information based on the road information. The curvature radius is corrected so as to satisfy the road structure rule according to the road construction time of the curve section to be processed.

  According to the structure of Claim 3, the curvature radius corrected beforehand so that road structure regulation may be satisfy | filled is used for correction | amendment of relaxation area length. Therefore, since the error with respect to the radius of curvature of the actual curve section can be reduced, the accuracy of the relaxation section length can be further improved.

  Invention of Claim 4 is the road shape estimation apparatus of any one of 1-3, The said road structure prescription | regulation prescribes | regulates the relationship between the design speed of a curve area, and the relaxation area length, Design speed acquisition means for acquiring the design speed of the curve section to be processed is further provided, and the section length correction means is adapted to satisfy the road structure rule corresponding to the design speed of the curve section to be processed. Correct the section length.

  According to the configuration of the fourth aspect, among the road structure regulations that define the relationship between the design speed and the relaxation section length, the road structure regulations corresponding to the design speed of the curve section are used to The relaxation section length is corrected. For this reason, the relaxation section length in the process target section can be estimated with higher accuracy.

  The invention according to claim 5 is the road shape estimation method by the control means for estimating the road shape, wherein the control means indicates the basic relaxation indicating the length of the relaxation section with respect to the curve section to be processed based on the road information. The road construction of the curve section to be processed is calculated from the structure regulation storage means for calculating the section length, determining the road construction time of the curve section to be processed, and storing the road construction time and the road structure regulation in association with each other. The road structure rule corresponding to the time is acquired, and the basic relaxation section length is corrected so as to satisfy the acquired road structure rule.

According to the method of claim 5, the basic relaxation section length of the processing target section generated based on the road information is corrected so as to satisfy the road structure rule corresponding to the road construction time of the processing target section. For this reason, due to the error included in the road information, the basic relaxation section length that is too small or too large beyond the road structure rule can be corrected to an appropriate range according to the road structure rule. For this reason, the precision of the relaxation area length in a process target area can be improved.

  The invention described in claim 6 is a road shape estimation program using a control means for estimating a road shape, wherein the control means stores a structure definition storage means for storing a road construction time and a road structure specification in association with each other; Basic information generating means for calculating a basic relaxation section length indicating the length of the relaxation section with respect to the curve section to be processed based on road information; and a construction time determination section for determining the road construction time of the curve section to be processed. , Provision information acquisition means for obtaining the road structure provision corresponding to the road construction time of the curve section to be processed, and section length correction for correcting the basic relaxation section length so as to satisfy the acquired road structure provision It functions as a means.

  According to the program of the sixth aspect, the basic relaxation section length of the processing target section generated based on the road information is corrected so as to satisfy the road structure rule corresponding to the road construction time of the processing target section. For this reason, due to the error included in the road information, the basic relaxation section length that is too small or too large beyond the road structure rule can be corrected to an appropriate range according to the road structure rule. For this reason, the precision of the relaxation area length in a process target area can be improved.

  Hereinafter, an embodiment in which the road shape estimation device of the present invention is embodied in a navigation device mounted on a vehicle will be described with reference to FIGS. In the present embodiment, the navigation device constitutes a driving support system that performs optimal shift control on a curve ahead of the vehicle in cooperation with an ECU that controls an automatic transmission (AT).

  FIG. 1 is a block diagram of a driving support system 1 of the present embodiment. The driving support system 1 includes a navigation device 2, a position detection sensor 20, a camera 24, and an ECU 25. The navigation device 2 includes a navigation unit 3 having a CPU 5, a RAM 6, a ROM 7, an image recognition processor 8, and a vehicle side I / F (interface) 9. The navigation unit 3 stores a road shape estimation program and corresponds to basic information generation means, construction time determination means, regulation information acquisition means, section length correction means, curvature radius acquisition means, design speed acquisition means, and control means. .

  The navigation unit 3 calculates the vehicle position based on the position detection sensor 20 mounted on the vehicle. In the present embodiment, the position detection sensor 20 includes a GPS receiver 21, a vehicle speed sensor 22, and a gyro sensor 23. The navigation unit 3 detects the absolute position such as latitude and longitude by radio wave navigation based on the GPS receiver 21. The navigation unit 3 calculates a relative position from the reference position by autonomous navigation based on the vehicle speed sensor 22 and the gyro sensor 23. Then, the vehicle position is specified by combining the absolute position and the relative position represented by latitude and longitude.

  The image recognition processor 8 acquires image data, for example, in units of several tens of milliseconds from the camera 24 provided in the host vehicle during traveling. The camera 24 is fixed to the rear end of the host vehicle so that the rear and rear sides of the vehicle are included in the imaging region 50 with the optical axis directed to the road surface (see FIG. 2). The camera 24 only needs to be able to photograph a road surface around the host vehicle, and may be attached to the front end or the side end of the host vehicle, or a plurality of cameras 24 may be attached.

When the image data is acquired from the camera 24, the image recognition processor 8 detects an auxiliary region provided in the curve section by a known image recognition method. The auxiliary area is an area in which the driver's visual range in the curve section is secured, or the road is widened due to the difference between the inner races. In addition, when the road is widened, the driver recognizes the widened area as a travelable area, so a zebra zone may be provided in the widened area in order to distinguish it from the driving lane. In this embodiment, a widened area and a zebra zone provided in the widened area are detected as auxiliary areas.

  In the zebra zone detection process, white lines such as the road center line, the road outer line, and the zebra zone Z1 (see FIG. 2) marked on the road are detected by a known white line detection method using image data taken by the camera 24. Is detected. Then, it is determined whether or not the detected white line pattern is a so-called zebra pattern with a stripe shape. If it is a zebra pattern, the region of the stripe pattern is recognized as a zebra zone Z1.

  In the widening area detection process, as shown in FIG. 3, the lane in which the host vehicle V1 travels in the straight section S located before the curve section C using the image data photographed before the curve section C. Is detected by a known white line detection method or the like. Even after entering the curve section C, the width of the lane in which the host vehicle V1 travels is calculated based on the image data acquired from the camera 24. Then, the newly calculated width is compared with the already calculated widths, the maximum value of the width in the curve section C is determined, and the maximum value is stored in the RAM 6. Further, at a predetermined timing such as when the curve is exited, the width of the straight section S is subtracted from the maximum value of the width of the curve section to calculate the widening amount ΔW. Then, it is determined whether or not the widening amount ΔW is equal to or greater than a predetermined value indicating that it is the auxiliary region, and when it is determined that the widening amount ΔW is equal to or larger than the predetermined value, the auxiliary region provided with the widening amount ΔW Is determined as the widened area Z2. Note that after the vehicle exits from the curve section C, the width of the straight section continuous to the exit of the curve section C may be subtracted from the maximum value of the width in the curve section to calculate the widening amount. .

  Next, each memory | storage part with which the navigation apparatus 2 is provided and the data stored in those memory | storage parts are demonstrated. The geographic information storage unit 10 stores road network data 11, road attribute data 12, and map drawing data 13 as road information.

  The road network data 11 is data indicating an identifier and coordinates of a node, an identifier and coordinates of a link connecting each node, and the like. Since the node is set at an intersection or a road end point, the curve shape of the road cannot be determined from each node. The road network data 11 is associated with each link and has a link cost set according to the link length, the number of lanes, and the like. The navigation unit 3 multiplies the link cost corresponding to the link from the current location to the destination by a predetermined coefficient, sums up these link costs, and searches for various recommended routes that minimize the total value.

  The road attribute data 12 includes road classification, construction time, topography, road width, number of lanes, design speed, and the like corresponding to each link. In the road classification, a classification such as “third type, second class” is stored. In this classification, roads are broadly classified into types 1 to 4, and further classified into various classes. A highway automobile national road and an automobile exclusive road in a rural area are classified as a first type, and an expressway automobile national road and an automobile exclusive road in an urban area are classified as a second type. Other roads in rural areas are of type 3 and other roads in urban areas are of type 4.

Further, the various types such as the first type are further classified into respective classes such as a first class, a second class,... Based on conditions set for each type. For example, the first type is classified from the first class to the fourth class according to the planned traffic volume, the type of road, and the terrain on which the road exists. In the first type, when the planned traffic volume is large, a higher level such as the first class is set, and as the planned traffic volume decreases, the second class, the third class, and so on. Become. In the first type, when the type of road is a road with high importance, such as a high-speed automobile national highway, a high-level series such as the first grade is set. Further, in the first type, a series having a higher level is set in the flat ground part than in the mountainous part.

  The construction time included in the road attribute data 12 is at least data indicating whether the road is a road constructed before the revision of the law of the road structure ordinance or a road constructed after the revision. . In the construction period, for example, a flag indicating whether it is before or after the revision may be stored, or a specific construction year may be stored. The road structure ordinance was revised in 1970, and the way of road planning and design differs before and after the revision. Therefore, the definition of the shape in the curve section is different before and after the revision of the road structure ordinance.

  The terrain included in the road attribute data 12 indicates “flat part”, “mountain part”, and the like. In addition, the terrain included in the road attribute data 12 is a flag indicating whether or not the place where the road was constructed is a place where a special curvature radius or the like is applied due to terrain conditions or other special reasons. Shown by. The width included in the road attribute data 12 indicates an average width in the link, and does not include the amount of widening in the curve section. The number of lanes included in the road attribute data 12 indicates the number of lanes on the road. The design speed included in the road attribute data 12 indicates a speed that is used as a reference in designing the road.

  The map drawing data 13 is data for displaying a map screen on a display (not shown) connected to the navigation device 2, and includes road shape data for drawing a plane curve shape of a road, It has background data for drawing an area. The road shape data has coordinates of a shape interpolation point for indicating a planar curve shape of the road. These shape interpolation points are set between nodes and along the curve shape between the nodes, but these only indicate the rough shape of the road, and are set at positions that deviate from the actual road shape. Or the set interval may be too large.

  In addition to the above-described radio navigation and autonomous navigation, the navigation unit 3 performs map matching that compares the road shape data with the traveling locus of the host vehicle, and matches the position of the host vehicle on the road. If the travel locus and the road shape data greatly deviate, the vehicle position is corrected. Thereby, the precision of the own vehicle position can be improved.

  The road law information storage unit 14 as the structure regulation storage means stores a plurality of curvature law tables 15 and a plurality of mitigation length law tables 16 as road structure regulations in association with the road construction time. Yes. These curvature law table 15 and relaxation length law table 16 are data created in advance mainly based on the road structure ordinance. Further, the curvature law table 15 and the relaxation length law table 16 indicate the curvature radius and the relaxation section length of the road determined by the road structure ordinance separately before and after the revision of the law.

  The navigation unit 3 uses the road network data 11 or the like to calculate the curvature radius of the curved section of the curved section and the length of the relaxation section that continues to the curved section, and further uses the tables 15 and 16 to calculate the curvature. The radius and the relaxation section length are corrected to be parameters used for the driving support process.

  As shown in FIG. 2, the curved section Ci is a curve (corner) having a constant curvature radius, but when the straight section S and the circular section Ci are directly connected, the curvature radius changes abruptly at the boundary. However, in addition to unreasonable driving operations, a large centrifugal force is suddenly applied to the passenger. For this reason, between the straight section S and the circular section Ci, there is usually provided a relaxation section Cl in which the radius of curvature is gently changed. The relaxation section Cl has a shape along the clothoid curve, and the length of the clothoid curve is expressed by the following formula 1. Note that L is a distance from the start point of the relaxation section Cl, R is a radius of curvature at a position away from the start point by L, and A is a clothoid coefficient.

R · L = A ² (Formula 1)
Therefore, when the relaxation section is connected to a circular section having a radius of curvature R, the total length from the start point to the end point of the relaxation section is A ² / R.

  The curvature law table 15 stored in the road law information storage unit 14 shown in FIGS. 4 to 9 defines a curvature radius of the circular section before the revision of the road structure ordinance and a curvature radius after the revision. And a table. In addition, each table before and after the revision includes a table in which the maximum value of the radius of curvature capable of marking the zebra zone, a table in which the widening amount is defined for the road segment and the radius of curvature, and a road It consists of a table that determines the minimum value of the radius of curvature according to the section and topography.

  More specifically, the first curvature law table 15A shown in FIG. 4 is a table corresponding to the revision of the road structure ordinance, and indicates the allowable maximum value Rmax of the radius of curvature at which the zebra zone can be marked. In this table 15A, the allowable maximum value Rmax of the radius of curvature of the circular section is set according to the range of the roadway, the road section, and the topography. The range of the width of the roadway is divided into two stages: “less than 12 m” and “more than 12 m and less than 16.5 m”. Further, when the allowable maximum value Rmax of the radius of curvature is not set, it indicates that it is not necessary to display a zebra zone in the curve section under the condition.

  The second curvature law table 15B shown in FIG. 5 is a table corresponding to the revision of the road structure ordinance, and indicates the allowable maximum value Rmax of the curvature radius that can be used to indicate the zebra zone. In this table 15B, unlike the first curvature law table 15A before the revision, an allowable maximum value Rmax of the curvature radius is simply set for each road section.

  A third curvature law table 15C shown in FIG. 6 is a table corresponding to the revision of the road structure ordinance, and indicates the amount of widening defined in the curve section. In this table 15C, the allowable range Rr of the radius of curvature set according to the road segment and the terrain is associated with the amount of widening that changes according to the width of the roadway. The amount of widening decreases as the value included in the allowable range Rr of the radius of curvature increases. The width of the roadway is divided into two stages, “less than 12 m” and “less than 12 m and less than 16.5 m”. The widening amount corresponding to the width of “less than 12 m” is “more than 12 m and less than 16.5 m” under the same conditions. It is smaller than the amount of widening.

  The fourth curvature law table 15D shown in FIG. 7 is a table corresponding to the revision of the road structure ordinance, and the amount of widening is set according to the road section. The amount of widening increases as the value included in the allowable range Rr of the radius of curvature decreases.

  A fifth curvature law table 15E shown in FIG. 8 is a table corresponding to the revision of the road structure ordinance, and is associated with the road section and the topography, and the allowable minimum radius Rmin of the curvature radius. In this table 15E, a general curve radius and a special curve radius are set for each road segment and terrain. The special curve radius is a radius of curvature that is applied in an unavoidable location due to terrain conditions or other special reasons, and the general curvature radius is a radius of curvature that is applied to other locations.

The sixth curvature law table 15F shown in FIG. 9 is a table corresponding to the revision of the road structure ordinance, and associates the design speed with the allowable minimum value Rmin of the curvature radius.
The mitigation length law table 16 shown in FIGS. 10 to 12 includes a table that defines the mitigation section length before the revision of the road structure ordinance and a table that defines the mitigation section length after the revision. If the relaxation zone length is too short, the rate of change of acceleration applied in the lateral direction (centrifugal direction) during turning is increased, causing unreasonable driving operations, and being too long is not preferable. For this reason, the minimum and maximum values of the relaxed section length are defined by the road structure ordinance, and the relaxed length law table 16 indicates a table indicating the allowable minimum value Lmin of the relaxed section length and the allowable maximum value Lmax. And a table.

  The first mitigation length law table 16A shown in FIG. 10 is a table corresponding to the revision of the road structure ordinance, and associates the road segment, the terrain and the radius of curvature with the allowable minimum value Lmin of the mitigation section length L. ing. In this table 16A, a longer relaxation section length L is set as the value included in the radius of curvature range decreases.

  The second relaxation length law table 16B shown in FIG. 11 is a table corresponding to the revision of the road structure ordinance, and associates the range of the radius of curvature with the allowable minimum value Lmin of the relaxation section length L. In this table 16B, the allowable minimum value Lmin of the relaxation section length L is set in the range of the general curve radius and the range of the special curve radius.

  The third mitigation length law table 16C shown in FIG. 12 associates the design speed with the permissible maximum value Lmax of the mitigation zone length regardless of before and after the revision of the road structure ordinance. This allowable maximum value Lmax is set to a length that can pass through the relaxation section in a predetermined time (for example, 5 seconds) when traveling in the relaxation section at the design speed. Accordingly, a larger allowable maximum value Lmax is set as the design speed increases.

  The correction information storage unit 17 stores curvature radius data 18 and relaxation section length data 19 corrected based on the curvature law table 15 and the relaxation length law table 16. The curvature radius data 18 stores the link identifier indicating the curve section and the curvature radius of the circular section of the curve section in association with each other. The relaxation section length data 19 stores a link identifier indicating a curve section and a relaxation section length in the curve section in association with each other.

  The radius of curvature data 18 and the relaxation zone length data 19 are used for driving support for a curve ahead of the vehicle, as described above. When the curvature radius data 18 and the relaxation section length data 19 corresponding to the curve section ahead of the host vehicle are stored in the correction information storage unit 17, the navigation unit 3 uses the curvature radius data 18 and the relaxation section length data 19. , The shift position, the timing of the shift change, etc. are calculated. Then, the ECU 25 (see FIG. 1) that drives the AT is controlled based on the shift position and the timing of the shift change. Based on a command from the navigation unit 3, the ECU 25 shifts up or down to improve stability when entering or turning a curve, and shifts up so that smooth acceleration is possible when leaving the curve.

Next, functions based on the road shape estimation program stored in the navigation unit 3 will be described. FIG. 13 is a functional block diagram of the navigation unit 3.
The own vehicle position determination unit 30 determines the own vehicle position based on the position detection sensor 20 shown in FIG. 1 by the radio navigation, autonomous navigation, and map matching. The basic curvature radius calculation unit 31 calculates a curvature radius (hereinafter referred to as a basic curvature radius Ri) based on the road network data 11, the road attribute data 12, and the map drawing data 13. The basic relaxation section length calculation unit 32 calculates a relaxation section length (hereinafter referred to as a basic relaxation section length Li) based on the road network data 11, the road attribute data 12, and the map drawing data 13.

  The image recognition unit 33 acquires image data from the camera 24 and performs the above-described image recognition processing based on the image data. Then, the presence / absence of a zebra zone in the curve section and the widening amount of the curve section are detected.

Based on the road attribute data 12, the road construction year determination unit 34 determines whether the road to be processed is before the road structure ordinance revision.
The specified value acquisition unit 35 acquires the presence / absence of a zebra zone and the widening amount of the curve section from the image recognition unit 33, and a flag indicating whether the road construction time is before or after the revision from the road construction year determination unit 34 Etc. Then, the curvature law table 15 and the relaxation length law table 16 corresponding to the detection result of the zebra zone and the widening and the road construction time are read, and the maximum value, minimum value or range of the curvature radius, the maximum value of the relaxation section length, or Get the minimum value.

  The curvature radius correction unit 36 compares the basic curvature radius Ri calculated by the basic curvature radius calculation unit 31 with the maximum value, minimum value, or range of the curvature radius acquired by the specified value acquisition unit 35, and thereby calculates the basic curvature. It is determined whether the radius Ri satisfies the maximum value, the minimum value, or the range of the acquired curvature radius. When the basic curvature radius Ri satisfies the maximum value, minimum value, or range of the acquired curvature radius, the curvature radius is stored as the curvature radius data 18 without correction.

  On the other hand, when the basic curvature radius Ri does not satisfy the maximum value, minimum value, or range of the acquired curvature radius, the coordinates of the node coordinates or the shape interpolation point (coordinate point) are not along the actual road shape. Probability is high. For example, as shown in FIG. 14, among the coordinate points P1 to P5 included in the curve section, when the coordinate point P2 is set at a position away from the curve L10 indicating the actual road shape, the adjacent coordinate point P1. The curve L1 connecting the coordinate point P2 and the curve L2 connecting the coordinate point P2 and the adjacent coordinate point P3 deviate from the curve L10 indicating the actual road shape. Then, when the basic curvature radius Ri is obtained with the coordinate points P1 to P3 as processing targets, a curvature radius smaller than or larger than the actual curvature radius is calculated. If the basic radius of curvature Ri exceeds the road structure ordinance, the basic radius of curvature Ri is determined to be large, and the maximum or minimum value of the curvature radius specified by the road ordinance is determined. The basic radius of curvature Ri is corrected so as to satisfy the value or range, and the corrected value is stored as the curvature radius data 18.

  The relaxation interval length correction unit 37 compares the basic relaxation interval length Li calculated by the basic relaxation interval length calculation unit 32 with the maximum value or the minimum value of the relaxation interval length acquired by the specified value acquisition unit 35, It is determined whether or not the relaxation interval length Li satisfies the maximum value or the minimum value of the acquired relaxation interval lengths. When the basic relaxation section length Li satisfies the maximum value or the minimum value of the acquired relaxation section length, the relaxation section length is stored as the relaxation section length data 19 without performing correction.

On the other hand, when the basic relaxation section length Li does not satisfy the maximum value or the minimum value of the acquired relaxation section length, the coordinates of the node coordinates or the shape interpolation points (coordinate points) are not along the actual road shape. Is estimated. For example, when calculating the basic relaxation section length Li, a clothoid curve and a coordinate point are fitted to each other, and a well-fitted section is set as the basic relaxation section length Li, but the coordinates of the coordinate point indicate an actual road shape. If it is set at a position away from the curve, an incorrect fitting result is calculated, and the basic relaxation interval length Li is shorter or longer than actual. Therefore, if the basic mitigation section length Li is too small or too large beyond the provisions of the road structure ordinance, it is determined that the basic mitigation section length Li has a large error, and the maximum or minimum value of the road structure ordinance is set. The basic relaxation interval length Li is corrected so as to satisfy, and the corrected value is stored as relaxation interval length data 19.
(Processing procedure)
Next, the processing procedure of this embodiment is demonstrated according to FIGS.

  As shown in FIG. 15, the navigation unit 3 first determines whether or not to start the shape prediction process for the curve section (step S1). Although the trigger for starting the shape prediction process is not particularly limited, for example, when the shape prediction process starts when the ignition switch is turned on or when a switch provided on the instrument panel or the like is turned on. to decide.

If it is determined that the shape prediction process is to be started (YES in step S1), whether a curve section that is ahead of the vehicle and has not been subjected to the shape prediction process is detected based on the road network data 11 and the map drawing data 13. It is determined whether or not (step S2). The history of the shape prediction process can be determined based on, for example, the curvature radius data 18 in the correction information storage unit 17.

A known method can be used as a method of detecting the curve section ahead of the vehicle position. For example, a predetermined coordinate point _Pn is identified from nodes or shape interpolation points (coordinate points) set in a predetermined range (for example, 1 km) ahead in the traveling direction from the vehicle position, and the coordinate point _Pn and The coordinates of three coordinate points P _{n−1 to} P _{n + 1} including the two preceding and following coordinate points are acquired. Then, the general formula meet any three points on the circumference, fit the three coordinate points _{P n-1 ~P} n ₊ 1 of coordinate, it calculates the radius of curvature _{R n} with respect to the coordinate point _{P n.} Furthermore, the calculated radius of curvature R _n is, and equal to or less than a predetermined value indicating a curve section, when it exceeds a predetermined value, it is determined that the coordinate point is not included in the curve section Thus, the radius of curvature is calculated for the three coordinate points P _{n to} P _{n + 2 with} the next coordinate point P _{n + 1} shifted in the direction of travel of the host vehicle.

The curvature radius R _n of points P _n of calculated on the basis of the three points the coordinates is equal to or less than the predetermined value mentioned above, it is determined that the coordinate point P _n is included in the curve section, coordinate points to be processed Is the coordinate point P _{n + 1} shifted by one point in the traveling direction, and the next radius of curvature R _{n + 1} is calculated. Next, when the calculated radius of curvature R _{n + 1} is equal to or less than a predetermined value, the curve direction formed by the coordinate points P _{n−1 to} P _{n + 1} targeted when calculating the previous radius of curvature R _n , It is determined whether or not the curve direction formed by the coordinate points P _{n to} P _{n + 2} is the same. If the directions are the same, the coordinate points P _{n to} P _{n + 1} are included in the same curve section. If the directions are different, it is predicted to be an S-shaped curve, so that it is recognized as a different curve section. A section including a coordinate point having a radius of curvature equal to or less than a predetermined value and having the same curve direction is recognized as a curve section. Further, the coordinates of the start point where the radius of curvature of the curve section is equal to or smaller than a predetermined value and the coordinates of the end point which is the last point where the radius of curvature is equal to or smaller than the predetermined value are stored. The curve section detected here is calculated by the navigation unit 3 based on the road network data 11 and the map drawing data 13 for the correction process of the curvature radius and the relaxation section length, and the curvature radius is a predetermined value. The start point and the end point, which is the last point whose radius of curvature is less than or equal to the predetermined value, do not necessarily match the actual curve start point (relaxation zone start point) and curve end point (relaxation zone end point). .

  When a curve section ahead of the host vehicle position is detected (YES in step S2), it is determined whether or not the host vehicle is before entering the curve section at that time (step S3). If it is determined that it is before the curve section entry (YES in step S3), a radius of curvature correction process (step S4) and a relaxation section length correction process are performed (step S5), and the curvature radius data 18 and the relaxation section length data 19 are processed. Is stored in the correction information storage unit 17, and it is determined whether or not the shape prediction process is to be terminated (step S8). For example, when the ignition switch is turned off or when a switch provided on the instrument panel is turned off, it is determined that the shape prediction process is finished. If it is determined not to end the shape prediction process (NO in step S8), the process returns to step S2 and the above steps are repeated.

  If it is determined in step S3 that the vehicle has entered the curve section (NO in step S3), it is determined whether or not the curve section has been exited (step S6). If the vehicle is traveling in the curve section and has not exited (NO in step S6), the process proceeds to step S8 described above to determine whether or not to end the shape prediction process.

If it is determined in step S6 that the curve section has been exited (YES in step S6), the curvature radius correction process is performed again (step S7). The curvature radius correction process performed here is the same as the curvature radius correction process performed in step S4. That is, in this embodiment, the curvature radius correction process is performed even after exiting the curve section to correct the curvature radius of the circular section. When the curvature radius correction process is performed, the process proceeds to step S8, and it is determined whether or not the shape prediction process is terminated. If it is determined that the shape prediction process is to be terminated (YES in step S8), the process is terminated.
(Curvature radius correction processing)
Next, the curvature radius correction process will be described with reference to FIGS. First, as shown in FIG. 16, the navigation unit 3 acquires the basic curvature radius Ri for the circular section in the curve section detected in step S2 (step S4-1). For example, the minimum curvature radius among the curvature radii of the curve section identified in step S2 is set as the basic curvature radius Ri. That is, because of the configuration of the curve section, the radius of curvature of the circular section is the smallest, so the minimum value of the radius of curvature in the curved section corresponds to the radius of curvature of the circular section. When the basic curvature radius Ri is calculated, the basic curvature radius Ri is temporarily stored in the RAM 6.

When the basic curvature radius Ri is acquired, a road construction time corresponding to the curve section to be processed is acquired based on the road attribute data 12 (step S4-2).
Further, it is determined whether or not a zebra zone has been detected in the curve section to be processed (step S4-3). Since the zebra zone is not detected before entering the curve (NO in step S4-3), the process proceeds to step S4-8 shown in FIG.

  In step S4-8, it is determined whether or not a widening amount has been detected in the curve section to be processed. Since the amount of widening is not detected before entering the curve (NO in step S4-8), the process proceeds to step S4-13.

  In step S <b> 4-13, the road classification and terrain are acquired from the road attribute data 12. When the road classification and the terrain are acquired, it is determined whether or not the road construction time acquired in step S4-2 is before the revision (step S4-14). If it is determined that the road construction time is before the revision (YES in step S4-14), the corresponding fifth curvature law table 15E before the revision is read (step S4-15). Then, the allowable minimum value Rmin of the radius of curvature corresponding to the road segment and terrain acquired in step S4-13 is retrieved from the fifth curvature law table 15E (see FIG. 8), and the allowable minimum value Rmin is acquired. (Step S4-17). For example, if the road section of the curve section corresponds to “Type 2”, the terrain is “mountainous part” and the place where the general curvature radius is applied, the allowable radius of curvature that can be designed in the curve section is allowed. The minimum value Rmin is “100 m”. When the allowable minimum value Rmin is acquired, it is temporarily stored in the RAM 6, and the process proceeds to step S4-20 shown in FIG.

  On the other hand, if it is determined in step S4-14 that the road construction time is after the revision (NO in step S4-14), the sixth curvature law table 15F is read (step S4-16), and the radius of curvature is based on the design speed. An allowable minimum value Rmin is acquired (step S4-17). When the allowable minimum value Rmin is acquired, it is temporarily stored in the RAM 6, and the process proceeds to step S4-20 shown in FIG.

  In step S4-20 and subsequent steps shown in FIG. 18, the maximum value, minimum value, or range of the curvature radius acquired in steps S4-1 to S4-18 is compared with the basic curvature radius Ri, and if necessary. The basic curvature radius Ri is corrected.

  First, in step S4-20, it is determined whether or not an allowable maximum radius value Rmax has been acquired. If it is before entering the curve section, only the allowable minimum value Rmin of the radius of curvature is acquired, so it is determined that the allowable maximum value Rmax is not acquired (NO in step S4-20), and step S4- Proceed to 23.

In step S4-23, it is determined whether or not an allowable radius Rr of curvature radius has been acquired. If it is before entering the curve section, it is determined that the allowable range Rr has not been acquired (NO in step S4-23), and the process proceeds to step S4-26.

  In step S4-26, it is determined whether or not the basic curvature radius Ri temporarily stored in the RAM 6 is less than the allowable minimum value Rmin acquired in step S4-17. When the basic curvature radius Ri is not less than the allowable minimum value Rmin (NO in step S4-26), the basic curvature radius Ri is stored in the correction information storage unit 17 as the curvature radius data 18 (step S4-28). If the basic curvature radius Ri is less than the allowable minimum value Rmin (YES in step S4-26), the basic curvature radius Ri is corrected so as to satisfy the allowable minimum value Rmin (step S4-27). In the present embodiment, the basic curvature radius Ri is set to the same value as the allowable minimum value Rmin, and the corrected curvature radius is stored in the correction information storage unit 17 as the curvature radius data 18 (step S4-28). When the curvature radius data 18 is stored, the relaxation section length correction process shown in FIG. 19 is performed.

  Since the curvature radius data 18 generated in this way is generated before entering the curve section, it can be used to set the shift position and the timing of the shift change for the curve section. For this reason, the reliability of driving assistance can be improved compared with the case where the basic curvature radius Ri is directly used for driving assistance processing.

  When entering the curve section, the image recognition processor 8 performs the zebra zone detection process and the widening amount detection based on the image data acquired from the camera 24 as described above.

  Then, as described above, when the own vehicle leaves the curve section, the curvature radius correction process is performed again. First, the curvature radius indicated by the curvature radius data 18 generated before entering the curve is set as the basic curvature radius Ri (step S4-1), and the road construction time is acquired (step S4-2).

  Further, it is determined whether or not a zebra zone has been detected in the exited curve section (step S4-3). When traveling in a curve section where no zebra zone is marked, it is determined that no zebra zone is detected (NO in step S4-3), and the process proceeds to step S4-8.

  On the other hand, if it is determined that the zebra zone has been detected by image recognition (YES in step S4-3), it is determined whether or not the road construction time acquired in step S4-2 is before the revision of the road structure ordinance (step). S4-4). If it is determined that the road construction time is before the revision (YES in step S4-4), the road law information storage unit 14 responds to the revision of the road structure ordinance and indicates the rules for marking the zebra zone. The first curvature law table 15A is read (step S4-5). Then, the road section, terrain, and width of the curve section are acquired from the road attribute data 12, and the allowable maximum radius value Rmax corresponding to the road section, terrain, and width is acquired from the first curvature law table 15A (step). S4-7). For example, when the road classification is “second type”, the topography is “mountainous region”, and the width is “12 m or more and less than 16.5 m”, the allowable maximum value Rmax is “50 m”. Note that if the allowable maximum value Rmax corresponding to the extracted road segment, terrain, and width is not set, the allowable maximum value Rmax is not acquired.

  On the other hand, if it is determined that the road construction time is after the revision (NO in step S4-4), the second curvature law table 15B corresponding to the revision is read from the road law information storage unit 14 (step S4-6). Then, the road segment of the curve section is acquired from the road attribute data 12, and the allowable maximum radius value Rmax corresponding to the road segment is acquired from the second curvature law table 15B (step S4-7). For example, when the road classification is “third type, first class”, the allowable maximum value Rmax is “50 m”.

  Next, in step S4-8, it is determined whether or not a widening amount in the curve section has been detected. When the widening amount is not detected in the curve section (NO in step S4-8), the process proceeds to step S4-13. In the present embodiment, even when a zebra zone is marked in a curve section, the zebra zone is regarded as an expanded area, and the amount of expansion is detected.

  When the widening amount is detected (YES in step S4-8), it is determined whether or not the road construction time acquired in step S4-2 is before the revision of the road structure ordinance (step S4-9). If it is before (YES in step S4-9), the corresponding third curvature law table 15C before the revision is read (step S4-10). When the third curvature law table 15C is read, the road section, terrain, and width are acquired from the road attribute data 12, and the allowable range Rr of the curvature radius corresponding to the widening amount, road section, terrain, and road width is acquired ( Step S4-12). For example, when the amount of widening is “2.0 or more”, the road classification is “type 2”, the terrain is “mountainous part”, and the width is “12 m or more and less than 16.5 m”, “50 m or more and less than 80” The allowable range Rr is acquired. In addition, when the permissible range Rr corresponding to the road classification, the terrain, the width, and the widening amount is not set, the permissible range Rr is not acquired.

  On the other hand, if the road construction time is after the revision of the road structure ordinance (NO in step S4-9), the corresponding fourth curvature law table 15D is read (step S4-11). Then, the road segment is acquired from the road attribute data 12, and an allowable range Rr corresponding to the detected widening amount of the curve section and the acquired road segment is acquired (step S4-12). For example, when the road classification is “second type” and the widening amount is “0.5 m or more and less than 0.75”, the allowable range Rr such as “100 or more and less than 150 m” is acquired. In addition, when the allowable range Rr corresponding to the extracted road segment and the widening amount is not set, the allowable range Rr is not acquired.

  Then, it progresses to step S4-13, and as above-mentioned, a road division and topography are acquired from the road attribute data 12, and it is judged whether road construction time is before revision of a road structure ordinance (step S4). -14). If it is before the revision (YES in step S4-14), the fifth curvature law table 15E is read (step S4-15), and the allowable minimum radius Rmin of the radius of curvature is acquired based on the road segment and the terrain (step S4-15). S4-17). If it is after the revision (NO in step S4-14), the sixth curvature law table 15F is read (step S4-16), and an allowable minimum value Rmin of the curvature radius is acquired based on the design speed (step S4-). 17).

  In step S4-20, it is determined whether or not the allowable maximum value Rmax is acquired. If the allowable maximum value Rmax is not acquired (NO in step S4-20), the process proceeds to step S4-23. On the other hand, when allowable maximum value Rmax is acquired (YES in step S4-20), it is determined whether or not curvature radius R stored in RAM 6 exceeds allowable maximum value Rmax (step S4-21). . Here, as described above, since the basic curvature radius Ri based on the curvature radius data 18 is stored, this basic curvature radius Ri is used.

  If the curvature radius R is equal to or less than the allowable maximum value Rmax (NO in step S4-21), the basic curvature radius Ri is stored in the RAM 6 as the latest curvature radius R, and the process proceeds to step S4-23. On the other hand, when the basic curvature radius Ri exceeds the allowable maximum value Rmax (YES in step S4-21), the basic curvature radius Ri is corrected so as to be equal to or less than the allowable maximum value Rmax (step S4-22). In the present embodiment, the curvature radius R (basic curvature radius Ri) is set equal to the allowable maximum value Rmax, stored in the RAM 6, and the process proceeds to step S4-23.

In step S4-23, it is determined whether or not the allowable range Rr has been acquired in steps S4-8 to S4-12. That is, even when correction is performed with the allowable maximum value Rmax, it is determined whether or not the radius of curvature R is appropriate by further determining whether or not the corrected value satisfies the allowable range Rr. Judgment can be made without omission so as to meet the regulations.

  If the allowable range Rr has not been acquired (NO in step S4-23), the process proceeds to step S4-26. When the allowable range Rr is acquired (YES in step S4-23), the curvature radius R stored in the RAM 6 is extracted, and it is determined whether the curvature radius R is outside the allowable range (step S4). -24). Here, the curvature radius R stored in the RAM 6 is the basic curvature radius Ri or the curvature radius R corrected by the allowable maximum value Rmax in step S4-22. When the curvature radius R is within the allowable range (NO in step S4-24), the curvature radius R is not corrected, but is stored in the RAM 6 as the latest curvature radius R, and the process proceeds to step S4-26.

  On the other hand, when the curvature radius R is outside the allowable range (YES in step S4-24), the curvature radius R is corrected so as to satisfy the allowable range Rr (step S4-25). Here, the curvature radius R is set to the same value as the value closer to the curvature radius R among the upper limit value and the lower limit value of the allowable range Rr.

  In step S4-26, as described above, it is determined whether or not the radius of curvature R stored in the RAM 6 is less than the allowable minimum value Rmin. At this stage, the curvature radius R stored in the RAM 6 is the basic curvature radius Ri or the curvature radius R corrected by at least one of the allowable maximum value Rmax and the allowable range Rr.

  When it is determined that curvature radius R is equal to or greater than allowable minimum value Rmin (NO in step S4-26), curvature radius R stored in RAM 6 at that time is stored as curvature radius data 18 (step S4-28). ). On the other hand, if it is determined in step S4-26 that the curvature radius R stored in RAM 6 is less than the allowable minimum value Rmin (YES in step S4-26), the curvature radius R becomes equal to or greater than the allowable minimum value Rmin. (Step S4-27). Here, the radius of curvature R is set to the same value as the allowable minimum value Rmin. When the curvature radius R is corrected, the corrected curvature radius is stored as the curvature radius data 18 (step S4-28). When the curvature radius data 18 is stored, the process proceeds to the relaxation section length correction process shown in FIG. The radius-of-curvature data 18 stored after exiting the curve is used when traveling the curve section next time.

  Thus, after leaving the curve section, the maximum value, minimum value, or range of the corresponding radius of curvature can be acquired using the zebra zone and the widening amount marked in the curve section. For this reason, when the zebra zone and the widening amount are detected, the maximum value, the minimum value, and the range of the radius of curvature can be acquired. In addition, when only the widening amount is detected in the curve section, it is possible to obtain the radius of curvature range and the minimum value. Furthermore, even when neither the zebra zone nor the widening amount can be detected, the minimum value of the curvature radius can be acquired. Thus, by extracting the curvature radius condition without omission, the curvature radius of the circular section can be corrected to an appropriate value even for a wide variety of curve sections.

As another method for correcting the basic curvature radius Ri, a method of correcting the curvature radius calculated based on the traveling locus of the vehicle by comparing the curvature radius Ri with the basic curvature radius Ri can be considered. When doing, it depends on the difference of the driving operation of the driver, the difference of the vehicle type, the weather and the like. On the other hand, in this embodiment, since the basic curvature radius Ri is corrected based on the road structure ordinance, the same correction can be performed in any vehicle regardless of the above-described factors. Therefore, the radius of curvature in the circular section can be set to an appropriate value in accordance with laws and regulations.
(Relaxation section length correction process)
Next, the relaxation section length correction process will be described with reference to FIG. This relaxation section length correction process is performed before the host vehicle enters the curve section as described above. The navigation unit 3 calculates the basic relaxation section length Li indicating the length of the relaxation section length based on the road network data 11 and the map drawing data 13 (step S5-1). As a method for calculating the relaxation section length based on the road network data 11 and the map drawing data 13, a known method can be used.

For example, the curvature corrected by the curvature radius correction process (step S4 or step S7) with reference to a clothoid coefficient table stored in advance in a storage unit (not shown) and associating a curvature radius with a value obtained by squaring the clothoid coefficient A. The square value of the clothoid coefficient A corresponding to the radius R is acquired, and the clothoid coefficient A is specified. Furthermore, the relaxation section length L = A ² / R is calculated according to the above-described formula 1 and the radius of curvature R of the circular portion, and is set as the basic relaxation section length Li. When the basic relaxation interval length Li is calculated, it is temporarily stored in the RAM 6.

  Next, the road construction time is acquired from the road attribute data 12 (step S5-2). Further, it is determined whether or not the road construction time is before the revision of the road structure ordinance (step S5-3). If it is determined that the road construction time is before the revision of the road structure ordinance (YES in step S5-3), the first mitigation length law table 16A corresponding to before the revision is read (step S5-4). When the first relaxation length law table 16A is read, the curvature radius data 18 generated by the curvature radius correction process, and the allowable minimum radius value Lmin of the curvature radius corresponding to the road classification and terrain acquired from the road attribute data 12 are acquired. (Step S5-6).

  If it is determined that the road construction time is after the revision (NO in step S5-3), the second mitigation length law table 16B corresponding to the revision is read (step S5-5). When the second relaxation length law table 16B is read, the curvature radius data 18 and the allowable minimum value Lmin of the curvature radius corresponding to the terrain acquired from the road attribute data 12 are acquired (step S5-6).

  Next, the design speed of the curve section is acquired based on the road attribute data 12 (step S5-7). Further, the third relaxation length law table 16C is read from the correction information storage unit 17 (step S5-8). Then, the allowable maximum value Lmax of the relaxation zone length corresponding to the design speed acquired in step S5-7 is acquired (step S5-9).

  When the allowable minimum value Lmin and the allowable maximum value Lmax are acquired, it is first determined whether or not the basic relaxation interval length Li calculated in step S5-1 is less than the allowable minimum value Lmin (step S5-10). If it is determined that the basic relaxation interval length Li is less than the allowable minimum value Lmin (YES in step S5-10), the basic relaxation interval length Li is corrected so as to satisfy the allowable minimum value Lmin (step S5-11). Here, the basic relaxation interval length Li is set to the same value as the allowable minimum value Lmin, and is temporarily stored in the RAM 6 as the latest relaxation interval length L.

  On the other hand, if it is determined that basic relaxation interval length Li is equal to or greater than allowable minimum value Lmin (NO in step S5-10), it is determined whether basic relaxation interval length Li exceeds allowable maximum value Lmax (step S5-12). ). If it is determined that basic relaxation interval length Li exceeds allowable maximum value Lmax (YES in step S5-12), basic relaxation interval length Li is corrected so as to satisfy allowable maximum value Lmax (step S5-13). . Here, the basic relaxation interval length Li is corrected to the same value as the allowable maximum value Lmax. Then, the corrected relaxation interval length L is overwritten on the relaxation interval length L stored in the RAM 6. On the other hand, if it is determined that basic relaxation interval length Li is equal to or smaller than allowable maximum value Lmax (NO in step S5-12), basic relaxation interval length Li is stored in RAM 6 and the process proceeds to step S5-14.

In step S5-14, the relaxation section length L stored in the RAM 6 is stored as the relaxation section length data 19.
In this way, by storing the mitigation length law table 16 in advance, the basic mitigation section length Li calculated based on the road network data 11 or the like can be corrected according to the road structure ordinance. For this reason, the relaxation section length can be set to an appropriate value without being influenced by factors such as the behavior of the host vehicle when traveling in the curve section. Moreover, since the curvature radius corrected based on the road structure ordinance is used for the correction of the relaxed section length, the accuracy of the relaxed section length can be further improved. Further, since the relaxation section length L used for driving support can be corrected before entering the curve section, it is possible to improve the reliability of driving support even for a curve section that has not traveled in the past. .

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the navigation device 2 includes the road law information storage unit 14 that stores the road construction time, the curvature law table 15 and the relaxation length law table 16 in association with each other. Further, based on the road shape data of the road network data 11 and the map drawing data 13, the basic relaxation section length Li for the curve section to be processed is generated. Further, the road construction time of the curve section to be processed is determined, and the mitigation length law table 16 corresponding to the road construction time of the curve section is acquired from the road law information storage unit 14. Then, the basic curvature radius Ri is corrected so as to satisfy the relaxation length law table 16. For this reason, if the basic relaxation section length Li is too small or too large beyond the road structure ordinance due to the error in the coordinates of the nodes or shape interpolation points, the basic relaxation section length Li is appropriate so as to satisfy the road structure ordinance. It is possible to correct within a range. Further, since the correction is performed in accordance with the road structure ordinance, the radius of curvature can be similarly corrected in each vehicle regardless of the traveling state of each vehicle. For this reason, the accuracy of the shape information in the curve section can be improved.

  (2) In the said embodiment, the 1st-2nd relaxation length regulation table 16A-16B prescribes | regulates the relationship between the curvature radius of the curved area of a curve area, and relaxation area length. Further, the navigation unit 3 acquires the radius of curvature of the curved section of the curve section. Further, the basic relaxation section length Li is corrected so as to satisfy the first and second relaxation length law tables 16A to 16B corresponding to the road construction time of the curved section and the curvature radius of the circular section. For this reason, the basic relaxation section length Li can be corrected based on the minimum value of the relaxation section lengths indicated by the first and second relaxation length law tables 16A to 16B. Therefore, the basic relaxation section length Li can be corrected to an appropriate range in accordance with the road structure ordinance, and the accuracy can be improved.

  (3) In the above embodiment, the navigation unit 3 calculates the basic curvature radius Ri of the circular section in the curve section to be processed based on the road shape data of the road network data 11 and the map drawing data 13. Further, the basic curvature radius Ri is corrected so as to satisfy the road structure regulations according to the road construction time of the curve section to be processed. Then, the corrected curvature radius is used for the relaxation section length correction process. Therefore, since the error in the radius of curvature used for the relaxation interval length correction process can be reduced, the accuracy of the relaxation interval length can be further improved.

  (4) In the above embodiment, the third relaxation length law table 16C defines the relationship between the design speed of the curve section and the relaxation section length. Further, the navigation unit 3 corrects the basic relaxation section length Li based on the maximum value of the relaxation section length corresponding to the design speed of the curve section from the third relaxation length law table 16C. Therefore, the basic relaxation section length Li can be corrected to an appropriate range in accordance with the road structure ordinance, and the accuracy can be improved.

In addition, you may change the said embodiment as follows.
In the above embodiment, the curvature law table 15 and the relaxation length law table 16 are tables based on road structure regulations, but may be tables based on laws other than road structure regulations. In this case, the basic curvature radius Ri can be corrected to an appropriate value in accordance with the strictest regulations by correcting the basic curvature radius Ri so as to satisfy the contents defined by each table.
In the above embodiment, as shown in FIGS. 16 to 17, processing for detecting the zebra zone and obtaining the allowable maximum value Rmax (steps S <b> 4-3 to S <b> 4-7), and detecting the widening amount and the allowable range The process of acquiring Rr (steps S4-8 to S4-12) and the process of acquiring the allowable minimum value Rmin from the road segment and the landform (steps S4-14 to S4-17) are performed in series. Further, as shown in FIG. 18, the correction based on the allowable maximum value Rmax (steps S4-20 to S4-22), the correction based on the allowable range Rr (steps S4-23 to step S4-25), and the allowable minimum value Correction based on Rmin (step S4-26 to step S4-27) is performed in series. In addition to this, the processing to be executed may be changed according to each situation, such as before entering the curve section and after leaving the curve section. For example, before entering the curve section, a process of obtaining the allowable minimum value Rmin from the road segment and the terrain (steps S4-14 to S4-17) and correction based on the allowable minimum value Rmin (steps S4-26 to S4-26). Only step S4-27) may be performed. Further, after exiting the curve, a process of detecting the zebra zone and obtaining the allowable maximum value Rmax (steps S4-3 to S4-7), and a process of detecting the widening amount and acquiring the allowable range Rr (step S4). −8 to step S4-12), correction based on the allowable maximum value Rmax (steps S4-20 to S4-22), and correction based on the allowable range Rr (steps S4-23 to S4-25). It may be. In this way, processing unnecessary in each situation can be omitted, and more efficient processing can be performed.

  In the above embodiment, in the radius of curvature correction process, the radius of curvature correction process and the relaxation zone length correction process are performed before entering the curve, but only the relaxation zone length correction process may be performed. Alternatively, the curvature radius correction process and the relaxation section length correction process may be performed after exiting the curve without being performed before entering the curve.

  In the above embodiment, when the specified values such as the allowable maximum value Rmax, the allowable range Rr, and the allowable minimum value Rmin of the radius of curvature can be acquired, all the specified values are acquired, Although the curvature radius Ri or the corrected curvature radius R is compared with each other, one of the specified values may be compared with the basic curvature radius Ri. For example, when the allowable range Rr is acquired, when the basic curvature radius Ri is corrected so as to satisfy the allowable range Rr, the curvature radius correction process is terminated. Further, when the allowable maximum value Rmax is acquired, the curvature radius correction process ends when the basic curvature radius Ri is corrected so as to satisfy the allowable maximum value Rmax. Further, when the allowable minimum value Rmin is acquired, if the basic curvature radius Ri is corrected so as to satisfy the allowable minimum value Rmin, the curvature radius correction process ends. Even in this case, the accuracy of the curvature radius R can be improved with a small amount of processing.

  In the above-described embodiment, the basic shape information indicating the shape of the curve section is the curvature radius. However, for example, the curvature radius and the arc length may be used, and other curve shape parameters may be used.

The curvature law table that defines the curvature radius may be configured other than the first curvature law table 15A to the sixth curvature law table 15F, or one or more of the tables 15A to 15F may be used. Moreover, you may add a table further to each table 15A-15F. As a table that can be added, for example, there is a table such as a curvature law table 15G shown in FIG. In this curvature law table 15G, the amount of widening is indicated by the nth power of a predetermined value, and this multiplier “n” is stored in the road attribute data 12 in association with each link. When the detected widening amount is “4 meters”, the widening amount corresponds to “2 to the nth power”, and therefore, in the row of the widening amount “2 to the nth power” in the table 15G, the road section of the curve section And an allowable maximum value Rmax of the radius of curvature corresponding to the topography. Further, the relaxation length law table that defines the relaxation section length may be configured other than the first to third relaxation length law tables 16A to 16C, or one or more of the tables 16A to 16C may be used. Good. Moreover, you may add a table further to each table 16A-16C.

  The processing target section may be a section having another shape such as a straight section other than a curve. When the processing target section is a straight section, the navigation unit 3 calculates the shape (length, width) and the like of the straight section based on the node and the shape interpolation point. The road structure regulations stipulate the road shape (length, width, etc.) of the straight section. Compare the straight line shape calculated based on the nodes and shape interpolation points with the road structure regulations. Correct to satisfy. Or it is good also as a section which consists of a plurality of roads, such as a plane intersection section, a solid intersection section, and a merge section. In this case, the navigation unit 3 calculates a relative relationship between roads such as a relative angle formed by a plurality of roads and a relative height based on the nodes and the shape interpolation points. In addition, the road structure specification specifies, for example, the road shape that the roads make relatively, such as the angle made by the roads and the relative positional relationship, and the relative relationship calculated based on the nodes and the shape interpolation points. The road structure rule is compared and the relative relationship is corrected so as to satisfy the road structure rule.

  The nodes and shape interpolation points indicating the outline of the road shape are included in the road network data 11 and the map drawing data 13, respectively. However, the nodes and the shape interpolation points may be included in the road network data 11, and the data The configuration is not particularly limited.

  In the above embodiment, the road shape estimation device is embodied in the navigation unit 3 mounted on the vehicle, but is specifically applied to an external device such as a server that transmits and receives data to and from the communication device mounted on each vehicle. May be used. When embodied in a server, the server collects information such as the presence / absence of a zebra zone in the curve section and the amount of widening from each vehicle, and corrects the curvature radius of the curve section based on the collected information and the curvature law table 15. To do. The corrected curvature radius data 18 is distributed to each vehicle. In addition, the server corrects the basic relaxation section length Li in the predetermined area calculated using the road network data 11 and the like based on the relaxation length law table 16 to generate the relaxation section length data 19 for each vehicle. To deliver. In this way, each vehicle that has received the radius of curvature data 18 or the relaxation zone length data 19 can obtain the radius of curvature data 18 for a curve zone that has not traveled in the past. Alternatively, the relaxation section length data 19 can be reflected in the travel support for the curve section that travels for the first time.

  In the above embodiment, the road shape estimation device is embodied in the navigation device 2 that constitutes the driving support system 1, but may be embodied in devices that constitute other systems. For example, a system that provides a driver with information on a curve section ahead of the vehicle, a system that supports driving operations when traveling in the curve section, a system that assists the driver's blind spot in the curve section, or a suspension device, a braking device, and a lighting device For example, the system may be embodied in a system that supports a vehicle by controlling an in-vehicle device other than the transmission.

The block diagram which shows the navigation system of this embodiment. The top view of the curve area where the zebra zone was marked. The top view of the curve area in which the widening was provided. The schematic diagram of the 1st curvature law table. The schematic diagram of the 2nd curvature law table. The schematic diagram of a 3rd curvature law table. The schematic diagram of the 4th curvature law table. The schematic diagram of the 5th curvature law table. The schematic diagram of a 6th curvature law table. The mimetic diagram of the 1st relaxation length law table. The mimetic diagram of the 2nd relaxation length law table. The schematic diagram of the 3rd relaxation length law table. The functional block diagram of the navigation apparatus of this embodiment. The schematic diagram explaining the coordinate of a node or a shape interpolation point, and an actual road shape. The flowchart which shows the whole process of this embodiment. The flowchart of a curvature radius correction process. The flowchart of the process. The flowchart of the process. The flowchart of a relaxation area length correction process. The schematic diagram of the curvature law table of another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Driving support system, 2 ... Navigation apparatus as road shape estimation apparatus, 3 ... Basic information generation means, construction time determination means, regulation information acquisition means, section length correction means, curvature radius acquisition means, design speed acquisition means, and control Navigation unit as means, 11 ... road network data as road information, 12 ... road attribute data as road construction time and road information, 13 ... map drawing data as road information, 14 ... road law as structure regulation storage means Information storage unit, 15 ... curvature law table as road structure regulation, 16 ... relaxation length law table as road structure regulation, C ... curve section, Ci ... circular section, Cl ... relaxation section, L ... relaxation section length, Li ... basic relaxation section length, Ri ... basic curvature radius, ΔW ... widening amount, Z ... zebra zone.

Claims (6)

A structure regulation storage means for storing a road construction time and a road structure regulation in association with each other;
Basic information generating means for calculating a basic relaxation section length indicating the length of the relaxation section with respect to the curve section to be processed based on the road information;
Construction time determination means for determining the road construction time of the curve section to be processed;
Regulation information obtaining means for obtaining the road structure regulation corresponding to the road construction time of the curve section to be processed;
A road shape estimation device comprising section length correcting means for correcting the basic relaxation section length so as to satisfy the acquired road structure rule. The road shape estimation apparatus according to claim 1,
The road structure rule prescribes the relationship between the radius of curvature of the curved section of the curved section and the length of the relaxed section,
A radius of curvature acquisition means for acquiring a radius of curvature of a curved section of the curve section to be processed;
The section length correcting means corrects the basic relaxation section length so as to satisfy the road structure rule corresponding to the acquired curvature radius and the road construction time of the curve section to be processed. Road shape estimation device. The road shape estimation apparatus according to claim 2,
The curvature radius acquisition means includes
A curvature radius of the curved section is calculated based on the road information, and the curvature radius is corrected so as to satisfy the road structure regulation according to the road construction time of the curve section to be processed. Road shape estimation device. The road shape estimation apparatus according to any one of claims 1 to 3,
The road structure rule prescribes the relationship between the design speed of the curve section and the relaxation section length,
A design speed acquisition means for acquiring a design speed of the curve section to be processed;
The section length correcting means corrects the basic relaxation section length so as to satisfy the road structure definition corresponding to the design speed of the curve section to be processed. In the road shape estimation method by the control means for estimating the road shape,
The control means is
Based on the road information, calculate the basic relaxation section length indicating the length of the relaxation section for the curve section to be processed,
Determine the road construction time of the curve section to be processed,
Obtaining the road structure prescription corresponding to the road construction time of the curve section to be processed from the structure prescription storage means for storing the road construction time and the road structure prescription in association with each other,
A road shape estimation method, wherein the basic relaxation section length is corrected so as to satisfy the acquired road structure rule. In the road shape estimation program using the control means for estimating the road shape,
The control means;
A structure regulation storage means for storing a road construction time and a road structure regulation in association with each other;
Basic information generating means for calculating a basic relaxation section length indicating the length of the relaxation section with respect to the curve section to be processed based on the road information;
Construction time determination means for determining the road construction time of the curve section to be processed;
Regulation information obtaining means for obtaining the road structure regulation corresponding to the road construction time of the curve section to be processed;
A road shape estimation program that causes the basic relaxation section length to function as section length correcting means that corrects the acquired road structure regulations.

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