JP2011034508A - Method for creating road shape data and device for acquiring road shape data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a road shape data creation method for creating road shape data required for executing curve vehicle speed control that gives a driver a slight sense of incongruity and to provide the same. <P>SOLUTION: Data on a plurality of positions (node points) Nd[n] on a road is acquired, and the degree of curvature Rc[n] of the road in each node point Nd[n] is calculated. A constant curvature degree section Cr# of a curve is identified on the basis of the variation of the degree of curvature in relation to the advancement in a point corresponding to the position data, and a constant degree of curvature Rm# and an end position Pe# of the constant curvature degree section Cr# are determined. The shape of a gentle curve section Eu# that connects two adjacent constant curvature degree sections Cr# with each other is calculated on the basis of the end position Pe# of each of the two constant curvature degree sections Cr# on the sides on which the same connect with the gentle curve section Eu# and the constant curvature degree Rm# of each of the two constant curvature degree sections Cr#. As road shape data, the data regarding a constant curvature degree section having the maximum degree of curvature in the curve is created and provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a road shape data creation method and a road shape data acquisition apparatus using the method.

  As shown in FIG. 8, on a general road, one curve is in order from a curve start point (curve entrance) to a curve end point (curve exit), an approach relaxation curve section, a constant bending degree section, and an exit. It consists of relaxation curve sections. The relaxation curve is composed of a clothoid curve, for example. The relaxation curve section is provided so that the driver can smoothly turn the steering wheel and then gradually turn it back without requiring the driver to operate the steering wheel suddenly. It is for doing so.

  2. Description of the Related Art Conventionally, vehicle speed control devices that perform automatic deceleration (curve vehicle speed control) when a vehicle passes through a curve so that the vehicle can stably pass through the curve at an appropriate speed are widely known. For example, in the device described in Patent Document 1, in order to set the vehicle speed to an appropriate vehicle speed when the vehicle enters a curve, the curve starts from the deceleration distance that requires deceleration when entering the curve and the current position of the vehicle. The remaining distance to the point is acquired. Then, the curve vehicle speed control is started when the decreasing remaining distance reaches the deceleration distance, and the curve vehicle speed control ends when the remaining distance becomes zero and the vehicle passes the curve starting point. Yes. That is, the curve vehicle speed control is executed so that the appropriate vehicle speed during the curve traveling is achieved at the curve start point.

  Moreover, in the apparatus described in Patent Document 2, the appropriate vehicle speed during curve traveling is determined based on the curve radius. Then, the determined appropriate vehicle speed is adjusted based on the road length of the section with a constant degree of flexion or the road length of the relaxation curve section (section composed of clothoid curve).

  Moreover, in the apparatus described in Patent Document 3, the following processing is performed for the purpose of acquiring a curvature change start point (that is, a curve start point). First, the starting point of a section with a constant degree of curvature in a curve on the road on which the vehicle is traveling and the curvature of that section are acquired. The section of the constant degree of flexion is identified based on the actual operation information of the vehicle (for example, a state where the steering angle is constant for a predetermined time or more). Next, information indicating a relaxation curve section (section composed of clothoid curve) connected to the constant curvature section is acquired based on the curvature of the constant curvature section. A curve start point is acquired based on the information indicating the relaxation curve section and the start point of the section with a constant degree of curvature. Then, suspension control is performed to adjust the characteristics of the suspension for the curve based on the acquired curve start point.

  That is, in the apparatus described in Patent Document 3, the curve start point is acquired based on the actual operation information of the vehicle. For this reason, in the curve where the vehicle travels for the first time, only the process of acquiring the curve start point is performed, and the suspension control cannot be executed. Suspension control is executed on the basis of the acquired curve start point in the curve that the vehicle travels for the second time or thereafter.

  In order to achieve curve vehicle speed control, it is necessary to estimate a road shape including a curve using a road database in which data representing road shape (road shape data) is stored. For example, in the apparatus described in Patent Document 4, a road shape including a curve is accurately estimated based on information on a large number of node points stored as road shape data in a road database. Specifically, a clothoid curve corresponding to the curve section is calculated based on the road database, and the calculated clothoid curve is adapted to the curve section. Then, the start point (curve entrance) and end point (curve exit) of the curve section are accurately set on the straight section.

Japanese Patent No. 3385812 JP 2006-331000 A JP 2009-32031 A JP 2005-214839 A

  As described above, on a general road, one curve is composed of an approach relaxation curve section, a constant bending degree section, and an exit relaxation curve section. In this case, the bending degree constant section in the curve has the largest bending degree (the curvature is large, the curvature radius is small). That is, the starting point of the section with a constant degree of flexion is the point at which the lateral acceleration acting on the vehicle is maximum and the foremost point when passing through a curve with a constant vehicle speed. Therefore, when the curve vehicle speed control is executed, it is preferable that the vehicle speed is adjusted so that the vehicle speed decreases to an appropriate value in consideration of the constant bending degree of the constant bending degree section in the vicinity of the starting point of the constant bending degree section. Conceivable. As a result, the curve vehicle speed control is likely to be in line with the driver's intention in consideration of the shape of the constant bending degree section where the degree of bending is the largest, and as a result, the discomfort given to the driver by the curve vehicle speed control is reduced. It is thought that you can.

  In such curve vehicle speed control, the vehicle speed is adjusted based on the end point position (particularly, the starting point, see point Cs in FIG. 8) and the constant bending degree of the constant bending degree section. In other words, as road shape data used for such curve vehicle speed control, data relating to a section with a constant degree of curvature is required. However, a method for creating and providing data relating to a section with a constant degree of flexion without using actual operation information of the vehicle (information on actual steering angle, etc.) has not yet been proposed.

  An object of the present invention is to provide a road shape data creation method capable of creating and providing road shape data necessary for execution of curve vehicle speed control with a little uncomfortable feeling given to a driver, and a road shape data acquisition device using the method There is to do.

  The road shape data creation method according to the present invention includes a road position data acquisition step (S1), a bending degree acquisition step (S2), a constant bending degree section identification step (S3), and a constant bending degree acquisition step (S4). And an end point position determining step (S5). Hereinafter, these steps will be described in order.

  In the road position data acquisition step (S1), a plurality of position data (Nd [n]) on the road is acquired. The plurality of position data (Nd [n]) can be acquired using, for example, road information stored in a vehicle navigation device (not necessarily mounted on the vehicle).

  In the bending degree acquisition step (S2), the bending degree (Rc [n]) of the road at a point (node point) corresponding to the position data (Nd [n]) is acquired. That is, the bending degree (Rc [n]) at each node point is acquired. The degree of bending (Rc [n]) can be acquired using, for example, road information stored in the navigation device.

  Each bending degree (Rc [n]) can be acquired based on the plurality of position data (Nd [n]). Specifically, based on the plurality of position data (Nd [n]), a first point (Nd [1]) and a second point (Nd [2] on the road) (from among a plurality of node points). ]) And the third point (Nd [3]) are determined, the first vertical line segment having the first point (Nd [1]) and the second point (Nd [2]) as both ends A bisector (Ls [1]), and a second vertical bisector (Ls) that has the second point (Nd [2]) and the third point (Nd [3]) as both ends. [2]) is calculated, and based on the intersection (Ins) of the first vertical bisector (Ls [1]) and the second vertical bisector (Ls [2]), the second The bending degree (Rc [2]) at the point (Nd [2]) can be calculated.

  Therefore, the process of acquiring the degree of bending at the second point by this method is repeatedly executed while sequentially changing the point set as the second point among the plurality of node points, so that the degree of bending at each node point ( Rc [n]) is acquired. By adopting this method, it is not necessary to store data on the degree of bending at each node point in advance. Therefore, the road information can be simplified.

  In the bending degree constant section identifying step (S3), the bending degree is based on the change state of the bending degree (Rc [n]) with respect to the progress of the point (node point) (Nd [n]) corresponding to the position data. A bending degree constant section (Cr #) in which (Rc [n]) is constant is identified. Examples of the constant bending degree section (Cr #) include “the bending degree (Rc [n] at the two points with respect to the distance between the two points corresponding to the two adjacent position data (Nd [n])”. ) In which the state in which the difference ratio is equal to or less than the predetermined value (hr1) is continuous, or “the section distance is equal to or greater than the predetermined distance (kr2) and is included in the section. A section in which the difference between the maximum value and the minimum value of the degree of curvature (Rc [n]) at a plurality of points corresponding to (Nd [n]) is equal to or less than a predetermined value (hr2) can be identified.

  The constant bend degree section includes not only the bend degree constant section corresponding to the curve section (that is, the section in which the bend degree is constant in the curve) but also the bend degree constant section corresponding to the straight section. Hereinafter, the constant bending degree section corresponding to the curve section may be referred to as “in-curve bending degree constant section”, and the constant bending degree section corresponding to the straight section may be simply referred to as “straight section”.

  In the constant bending degree acquisition step (S4), a constant bending degree (Rm #) of the constant bending degree section (Cr #) is acquired. The constant bending degree (Rm #) can be set to, for example, an average value of bending degrees of a plurality of node points included in the constant bending degree section (Cr #). On the basis of this constant degree of bending (Rm #), a section within the curve having a constant degree of bending and a straight section can be identified. Specifically, when the constant curvature radius (Rm #) as a constant curvature is larger than a predetermined value (or when the constant curvature (1 / Rm #) as a constant curvature is smaller than a predetermined value), the straight section Otherwise, it is identified as a section with a constant degree of bending in the curve. Hereinafter, the constant bending degree (Rm #) of the section in which the bending degree in the curve is constant may be referred to as “constant bending degree in the curve”. In the constant bending degree acquisition step (S4), in particular, the constant bending degree (Rm #) in the curve is acquired.

  In the end point position determination step (S5), the position (Pe #) of the end point of the constant bending degree section (Cr #) is determined. The end point position (Pe #) may be a node point corresponding to both ends of the plurality of node points included in the constant bending degree section (Cr #), or may be in the vicinity of the node point corresponding to the both ends. It may be a point (for example, a point that interpolates a node point corresponding to both ends and the adjacent node point). Hereinafter, the end point position (Pe #) of the section with a constant degree of bending in the curve may be referred to as “curve end position”, and the end position (Pe #) of the straight section may be referred to as “straight end position”. In the end point position determining step (S5), both the curve end point position and the straight line end point position can be determined. In particular, the curve end point position is determined.

  According to the above method, as the road shape data, the end point position (particularly, the curve end point position) of the constant bend degree section, which is data related to the bend degree constant section having the largest bend degree in the curve, and the constant bend degree section A certain degree of bending (particularly, a certain degree of bending in the curve) can be created and provided easily and easily without using actual operation information of the vehicle (information on the actual steering angle, etc.). That is, the curve shape data required for executing the curve vehicle speed control with a little uncomfortable feeling given to the driver can be created and provided easily and easily.

  In the road shape data creation method according to the present invention, the shape of the relaxation curve section (Eu #) connecting the two adjacent constant curvature sections (Cr #) identified by the constant curvature section identification step (S3). Are connected to the relaxation curve section (Eu #) of the two constant bending degree sections (Cr #) and the end point positions (Pe #) of the two constant bending degree sections (Cr #) and the two constant bending degree sections (Cr #). A relaxation curve shape calculation step (S6) for calculating based on each of the constant bending degrees (Rm #) of each may be provided. Here, the shape of the relaxation curve section (Eu #) can be calculated assuming a clothoid curve.

  According to this, regardless of the length of the section connecting the two adjacent constant sections of bending degree, the data relating to the shape connecting this section appropriately and smoothly (for example, clothoid coefficient (clothoid parameter) representing a clothoid curve) ) Can be computed. Here, as a combination of two adjacent bend degree constant sections, the in-curve bend degree constant sections and the in-curve bend degree constant section and the straight section may be mentioned.

  Further, when the bending directions of the two adjacent in-curve constant curvature sections (Crf, Cri) are different, for example, two types of relaxation curves (for example, two types of clothoid curves) are connected as in the following procedure. Thus, data (for example, two clothoid coefficients) relating to a shape that appropriately and smoothly connects two adjacent curved inflection constant intervals can be calculated.

  That is, an intermediate position (Pmd) at which the bending degree (Rc [n]) takes a value corresponding to a straight line section is determined in a section connecting the two in-curve bending degree constant sections (Clf, Cri). The shape of the first relaxation curve section (Eug) continuing from the first constant degree of flexion section (Clf) among the two in-curve constant degree of curvature sections (Clf, Cri) is the first constant degree of flexion section (Clf). The end point position (Peg) on the side connected to the first relaxation curve section (Eug), the constant bending degree (Rmf) of the first bending degree constant section (Clf), and the intermediate position (Pmd) Calculated based on Similarly, the shape of the second relaxation curve section (Euh) that is continuous with the second constant bending degree section (Cri) of the two in-curve constant degree bending sections (Clf, Cri) is the second constant bending degree section. (Cri) the end point position (Pei) on the side connected to the second relaxation curve section (Euh), the constant bending degree (Rmi) of the second bending degree constant section (Cri), and the intermediate position ( Pmd) is calculated. The shape of the relaxation curve section connecting the two in-curve bending degree constant sections (Clf, Cri) connects the first and second relaxation curve sections (Eug, Euh) at the intermediate position (Pmd). Is calculated into the shape obtained.

  The road shape data acquisition apparatus according to the present invention includes a road position data acquisition step (S1), a bending degree acquisition step (S2), and a constant bending degree section identification step (for the road shape data creation method according to the present invention described above). S3), road position data acquisition means (B1) and bending degree acquisition means (B2) in which the same processes as those performed in the respective steps of the constant bending degree acquisition step (S4) and the end point position determination step (S5) are performed. ), A certain degree of bending section identifying means (B3), a certain degree of bending degree obtaining means (B4), and an end point position determining means (B5). Furthermore, relaxation curve shape calculation means (B6) in which the same processing as that performed in the above-described relaxation curve shape calculation step (S6) may be provided.

It is a functional block diagram when road shape data is created by the road shape data creation method (road shape data acquisition device) according to the embodiment of the present invention. It is a figure for demonstrating the method of calculating the curvature degree of the road in each node point. It is the figure which showed the typical example of the road shape containing a curve. It is the graph which showed the relationship between the position about a road shown in FIG. 3, and a bending degree. It is a flowchart which shows the flow of a process at the time of calculating the shape of a relaxation curve area in the case where two sections with a constant degree of bending are connected without going through a straight line section. It is the figure which showed an example of the road shape in the case where two sections with a constant degree of bending are connected without going through a straight section. It is the graph which showed the relationship between the position about the road shown in FIG. 6, and a bending degree. It is a figure for demonstrating the typical structure of the road containing a curve.

  Embodiments of a road shape data creation method (road shape data acquisition apparatus) according to the present invention will be described below with reference to the drawings. First, a process when road shape data is created by a road shape data creation method (road shape data acquisition apparatus) according to an embodiment of the present invention will be described with reference to FIG.

  In the road position data acquisition step S1 (road position data acquisition means B1), a plurality of position data Nd [n] on the road is acquired. These position data Nd [n] are stored and stored in advance in a predetermined storage medium (such as a hard disk). The position data Nd [n] can be stored as latitude / longitude information. Hereinafter, a point corresponding to the position data Nd [n] is referred to as “node point Nd [n]”.

  In the bending degree acquisition step S2 (flexion degree acquiring means B2), the road bending degree Rc [n] corresponding to each node point (position data) Nd [n] is acquired. As the bending degree Rc [n], a curvature radius Rc, a curvature 1 / Rc, or the like can be used. The degree of bending Rc [n] can be stored in a storage medium in association with the position data (node point) Nd [n].

  Hereinafter, a method of calculating the bending degree Rc [n] at one node point based on three adjacent position data (node points) Nd [n] will be described with reference to FIG. As shown in FIG. 2, first, the first node point Nd [1], the second node point Nd [2], and the third node point Nd [3] are selected from the node points Nd [n]. The These selected node points need not be adjacent node points, but are adjacent node points.

  Based on the first node point Nd [1] and the second node point Nd [2], a first vertical line segment having both ends of the first node point Nd [1] and the second node point Nd [2]. The bisector Ls [1] is calculated. Similarly, based on the second node point Nd [2] and the third node point Nd [3], a line segment having both ends of the second node point Nd [2] and the third node point Nd [3] is used. A second vertical bisector Ls [2] is calculated.

  Next, an intersection point Ins between the first vertical bisector Ls [1] and the second vertical bisector Ls [2] is determined. The distance (= curvature radius) between the intersection Ins and the second node point Nd [2] is calculated as the bending degree Rc [2] at the second node point Nd [2]. By the above method, the bending degree Rc [2] at the second node point Nd [2] is acquired based on the first, second, and third node points Nd [1], Nd [2], Nd [3]. The

  The process of acquiring the degree of bending at the second node point Nd [2] by this method is repeatedly executed while sequentially changing the point set as the second node point Nd [2] among the plurality of node points Nd [n]. As a result, the bending degree Rc [n] at each of the plurality of points Nd [n] is acquired. By adopting this method, it is not necessary to store in advance the degree of flexure data at a plurality of node points Nd [n]. Therefore, the stored road information can be simplified.

  Hereinafter, the description will be continued with reference to FIGS. FIG. 3 shows a typical example of a road shape including a curve. FIG. 4 shows the relationship between the position and the bending degree for each node point Nd [n] on the road shown in FIG. In FIG. 4, the curvature 1 / Rc is used as the bending degree Rc [n] of each node point Nd [n].

  In the constant bending degree section identifying step S3 (fixed degree bending section identifying means B3), the bending degree Rc is based on the plurality of position data (node points) Nd [n] and the corresponding bending degree Rc [n]. A flexion constant section Cr # in which [n] is constant is identified. The bending degree constant section Cr # includes not only a section where the bending degree Rc [n] is constant in the curve but also a straight section. Hereinafter, a section in which the degree of bending Rc [n] is constant in the curve may be referred to as a section in which the degree of bending in the curve is constant. Note that “#” appended to the end of various symbols and the like is a comprehensive notation of one alphabetic character.

  The identified constant bending degree section Cr # is further identified as either a straight section or a constant in-curve bending degree section. In the example shown in FIGS. 3 and 4, the sections Cra, Crc, and Cre are identified as the constant bending degree section Cr #. Among these, the sections Cra and Cre are identified as straight sections, and the section Crc is bent in the curve. Is identified as a constant interval. Hereinafter, these identification methods will be described.

  The bending degree constant section Cr # is identified based on the change state of the bending degree Rc [n] with respect to the progress (ie, distance) of the point (node point) Nd [n] corresponding to the position data. Specifically, for example, the ratio of the difference in the degree of curvature Rc [n] at the two node points Nd [n] to the distance between the two adjacent node points Nd [n] is equal to or less than a predetermined value hr1. Can be identified as a constant bending degree section Cr #.

  In addition, the difference between the maximum value and the minimum value of the degree of curvature Rc [n] at a plurality of continuous node points Nd [n] included in the section in which the section distance is equal to or greater than the predetermined distance kr2. A section in which (variation width) is equal to or less than a predetermined value hr2 is identified as a section with constant bending degree Cr #. In this case, a window (see FIG. 4) corresponding to the section distance kr2 and the bending degree fluctuation width hr2 is scanned, and whether or not continuous position data (node point) Nd [n] fits in the window being scanned. By sequentially determining whether or not, the constant bending degree section Cr # can be identified.

  In the constant bending degree acquisition step S4 (constant bending degree acquisition means B4), the constant bending degree Rm # (more specifically, the constant curvature radius Rm # or the constant curvature 1 / Rm # in the constant bending degree section Cr #). ) Is acquired. The constant bending degree Rm # can be set to, for example, an average value of the bending degrees Rc [n] of a plurality of node points Nd [n] included in the constant bending degree section Cr #. Based on the constant bending degree Rm #, the constant bending degree section Cr # can be identified as either a constant bending degree in-curve section or a straight section. Specifically, when the constant curvature radius Rm # is larger than the predetermined value rc1 (or when the constant curvature 1 / Rm # is smaller than the predetermined value kc1 (= 1 / rc1)), the constant curvature degree section Cr # is a straight section. Otherwise, the constant curvature degree section Cr # is identified as the constant curve in-curve degree section. Hereinafter, the constant bending degree Rm # in the section where the bending degree within the curve is constant may be particularly referred to as “constant bending degree within the curve”.

  In the end point position determination step S5 (end point position determination step B5), the end point position Pe # of the constant bending degree section Cr # is determined. When the constant curvature degree section Cr # is a constant in-curve degree curvature section, the end point position Pe # is referred to as a “curve end position”. When the constant curvature degree section Cr # is a straight section, the end position Pe # is Sometimes referred to as “straight end point position”. It should be noted that the above-mentioned “identification of whether the in-curve bending degree constant section or the straight section” is performed may be executed in this end point position determining step S5 (end point position determining step B5).

  In the example shown in FIGS. 3 and 4, the points Pec and Ped are determined as the curve end point position Pe #, and the points Peb and Pee are determined as the straight end point position Pe #. The curve end point positions Pec and Ped correspond to the start point and end point of the in-curve bending degree constant section Crc, respectively. In the curves shown in FIGS. 3 and 4, the in-curve constant curvature section Crc has the largest degree of curvature (the curvature is large and the curvature radius is small). Therefore, the curve end point positions Pec and Ped can be said to be the points at both ends of the section having the greatest degree of bending in the curves shown in FIGS. The straight end point positions Peb and Pee correspond to the end point (that is, the curve entrance) of the approach straight line section Cra and the start point (that is, the curve exit) of the exit straight line section Cre, respectively.

  The curve end point position Pe # and the straight end point position Pe # may be node points themselves corresponding to both ends of the plurality of node points Nd [n] included in the constant bending degree section Cr #. It may be a point in the vicinity of the corresponding node point Nd [n]. The points in the vicinity of the node point Nd [n] corresponding to both ends are, for example, the node point Nd [n] corresponding to both ends and the adjacent node point Nd [n] (= nodes not included in the bending degree constant section) Point Nd [n]).

  In the relaxation curve section shape calculation step S6 (relaxation curve section shape calculation means B6), the shape of the relaxation curve section Eu # connecting two adjacent bending degree constant sections Cr # (the bending degree corresponding to the position Pd # in Eu #). Rd #) is calculated based on the end point position Pe # and the constant bending degree Rm #. In the calculation of the bending degree Rd #, it is assumed that the relaxation curve section Eu # is constituted by a clothoid curve. That is, in the relaxation curve section, it is assumed that the change of the curvature (reciprocal of the radius of curvature) 1 / Rd # with respect to the change (distance) of the position Pd # is expressed linearly, and the bending degree Rd # with respect to the position Pd # is Calculated. Then, a clothoid coefficient (also referred to as a clothoid parameter) Kc # representing the relationship between Pd # and Rd # is calculated.

  In the example shown in FIGS. 3 and 4, the shape of the relaxation curve section Eub (the bending degree Rdb corresponding to the position Pdb in the Eub) and the clothoid coefficient Kcb are the end point positions (straight lines) of the constant bending degree section (straight section) Cra. End point position Peb, constant bend degree section (curve in-curve constant section) Crc end point position (curve end point position) Pec, constant bend degree section (straight section) Cra constant bend degree (curvature = 0), and bend Is calculated based on a constant degree of curvature (constant degree of curvature in the curve) Rmc. The clothoid coefficient Kcb of the relaxation curve section Eub is based on a relational expression of Kcb = √ (1 / Gb) using the gradient (change in curvature (curvature) with respect to the progress (distance) of the node point) Gb shown in FIG. Can be calculated.

  Similarly, the shape of the relaxation curve section Eud (the bending degree Rdd corresponding to the position Pdd in Eud) and the clothoid coefficient Kcd are the end point position (straight end point position) Pee and the bending degree of the constant bending degree section (straight section) Cre. Fixed section (curved bending degree constant section) Crc end point position (curve end point position) Ped, fixed bending degree section (straight section) Cre fixed bending degree (curvature = 0), and bending degree constant section (curved bending within curve) It is calculated based on a constant degree of curvature of Crc (a constant degree of curvature in the curve) Rmc. The clothoid coefficient Kcd of the relaxation curve section Eud is based on the relational expression of Kcd = √ (1 / Gd) using the gradient (change in curvature (curvature) with respect to the progression (distance) of the node point) Gd shown in FIG. Can be calculated.

  As described above, the end point position Pe # (particularly the curve end point position) of the constant bending degree section Cr # calculated as described above, the constant bending degree Rm # (particularly, the constant bending degree within the curve) of the constant bending degree section Cr #, In addition, the bending degree Rd # (or clothoid coefficient Kc #) with respect to the position Pd # of the relaxation curve section Eu # is stored in the road shape database DB as road shape data for representing the road shape. This road shape database DB can be utilized in a vehicle speed control device that performs automatic deceleration (curve vehicle speed control) when the vehicle passes through a curve so that the vehicle can stably pass through the curve at an appropriate speed.

  As described above, according to the road shape data creation method (road shape data acquisition apparatus) according to the embodiment of the present invention, a plurality of position data (node points) Nd [n] (latitude / longitude information) on the road is acquired. The road bending degree Rc [n] at each node point Nd [n] is calculated. Based on the change of the bending degree Rc [n] with respect to the progress of the node point Nd [n] (that is, the relationship between the distance and the changing state of the bending degree), the in-curve bending degree constant section Cr # ("#" at the end of the symbol) Is a comprehensive notation of one alphabetic character), and the in-curve constant bending degree Rm # and the curve end point position Pe # for Cr # are determined.

  In a typical curve composed of an approach relaxation curve section, an in-curve bending constant section, and an exit relaxation curve section in order from the curve entrance to the curve exit, the constant bending degree section has the highest bending degree in the curve. . That is, the starting point of the section with a constant degree of flexion is the point at which the lateral acceleration acting on the vehicle is maximum and the foremost point when passing through a curve with a constant vehicle speed. Therefore, when curve vehicle speed control is executed so that the vehicle passes smoothly through the curve, the starting point of the in-curve constant curvature section Cr # (point Pec in FIG. 3) and the in-curve constant curvature Rm # (FIG. 3). Then, it is preferable that the vehicle speed be adjusted based on at least the curvature radius Rmc).

  According to the present embodiment, as the road shape data, the end point position of the constant bending degree section and the constant bending degree of the constant bending degree section, which are data related to the fixed bending degree section within the curve, are the vehicle. The actual operation information (actual steering angle information, etc.) can be created and provided simply and easily. That is, the curve shape data required for executing the curve vehicle speed control with a little uncomfortable feeling given to the driver can be created and provided easily and easily.

  Furthermore, the shape of the relaxation curve section Eu # that connects the two adjacent adjacent constant curvature degrees Cr # is the same in each of the two constant curvature sections Cr # (on the side connected to the relaxation curve section Eu #). The calculation is based on the end point position Pe # and the constant bending degree Rm # of each of the two constant bending degree sections Cr #. As a result, regardless of the length of the section connecting the two adjacent adjacent constant degrees of flexion, the combination of the two adjacent constant constant degrees of curvature is “inter-curve constant degree sections” or “ Regardless of “a section with a constant degree of bending and a straight section”, data (for example, a clothoid coefficient representing a clothoid curve) regarding a shape that connects the sections appropriately and smoothly can be calculated.

  Hereinafter, the calculation of the shape of the relaxation curve section in the case where the two sections with a constant degree of bending are connected without going through the straight section will be added with reference to FIGS. FIG. 5 shows the flow of processing in this case. FIG. 6 shows an example of the road shape in this case. FIG. 7 shows the relationship between the position and the bending degree for the road shown in FIG.

  As shown in FIG. 5, first, at step 505, the end point position Pe # of the constant bending degree section Cr # is acquired. In step 510, a constant bending degree Rm # of a constant bending degree section Cr # is acquired. Next, at step 515, it is determined whether one of the two adjacent constant bending degree sections Cr # is a straight section.

  The case where one of the two adjacent constant curvature sections Cr # is a straight section is, for example, the above-described two constant curvature sections Cr #, Cra and Crc shown in FIGS. 3 and 4 described above, or This is a case where Crc and Cre are employed. In this case, an affirmative determination (Yes) is made in step 515, and in step 520, the respective shapes of the relaxation curve sections Eub and Eud are calculated assuming a clothoid curve based on the same method as described above.

  On the other hand, when one of the two adjacent constant bending degree sections Cr # is not a straight section (that is, when both sections are curved sections), for example, as two adjacent constant bending degree sections Cr #, 6. This is a case where Crk and Cri or Cri and Clf shown in FIG. 7 are employed. In this case, a negative determination (No) is made in step 515, and in step 525, it is determined whether or not the bending directions of the two adjacent in-curve bending degree constant sections Cr # are the same. Whether the bending directions are the same is determined based on the sign of Rm #. Specifically, if the signs of Rm # match, it is determined that the bending method is the same, and if not, it is determined that the bending direction is different.

  The case where the bending directions of two adjacent in-curve degree-of-curvature constant sections Cr # are the same is, for example, the two adjacent in-curve degree-of-curvature constant sections Cr # are adopted by Crk and Cri shown in FIGS. This is a case where there can be two in-curve bend degree constant sections Cr # having different bend degree Rm # and the same bend direction in one curve. In this case, an affirmative determination (Yes) is made in step 525, and the process of step 520 is performed. That is, also in this case, based on the same method as described above, the shape of the relaxation curve section Euj is calculated assuming a clothoid curve.

  Specifically, the shape of the relaxation curve section Euj (the bending degree Rdj corresponding to the position Pdj in Euj) and the clothoid coefficient (clothoid parameter) Kcj are the end point position Pek and the constant bending degree section Cri of the constant bending degree section Crk. Is calculated based on the end point position Pej, the constant bending degree Rmk of the constant bending degree section Crk, and the constant bending degree Rmi of the constant bending degree section Cri. The clothoid coefficient Kcj of the relaxation curve section Euj can be calculated based on the relational expression Kcj = √ (1 / Gj) using the gradient Gj shown in FIG.

  The case where the bending directions of two adjacent in-curve-curvature constant intervals Cr # are different means that, for example, Clf and Cri shown in FIGS. 6 and 7 are adopted as two adjacent in-curve-curvature constant intervals Cr #. This is the case. In this case, a negative determination (No) is made in step 525, and in step 530, first, an intermediate position Pmd in a section connecting two adjacent constant bending degree sections Cr # is determined. The intermediate position Pmd is determined as a position (corresponding to a straight line section) where the curvature is substantially “0” (the curvature is less than a predetermined value 1 / rc1).

  Next, in step 535, the shape of the first relaxation curve section Eug that is continuous with the first constant curvature degree section Crf of the two adjacent in-curve curvature constant sections Cr # is calculated assuming a clothoid curve. The Specifically, the shape of the relaxation curve section Eug (the bending degree Rdg corresponding to the position Pdg in the Eug) and the clothoid coefficient Kcg are the end point position Peg of the constant bending degree section Clf and the constant bending degree of the constant bending degree section Clf. Calculation is performed based on Rmf and the intermediate position Pmd. The clothoid coefficient Kcg of the relaxation curve section Eug can be calculated based on the relational expression Kcg = √ (1 / Gg) using the gradient Gg shown in FIG.

  Similarly, in step 540, the shape of the second relaxation curve section Euh that is continuous with the second constant curvature degree section Cri of two adjacent in-curve curvature constant sections Cr # is calculated assuming a clothoid curve. Is done. Specifically, the shape of the relaxation curve section Euh (the degree of curvature Rdh corresponding to the position Pdh in the Euh) and the clothoid coefficient Kch are the end point position Pei of the constant degree of curvature section Cri and the constant degree of curvature of the constant degree of curvature Cri. Calculation is performed based on Rmi and the intermediate position Pmd. The clothoid coefficient Kch of the relaxation curve section Euh can be calculated based on the relational expression Kch = √ (1 / Gh) using the gradient Gh shown in FIG.

  In this way, in the case of a road shape (so-called S-shaped curve) in which the adjacent in-curve degree-of-curvature constant section Cr # in which two adjacent bending directions are different is connected without passing through the straight section, the inflection point of the degree of curvature is at the intermediate position Pmd. To be determined. Then, a section connecting the two sections with a constant degree of bending is divided into two relaxation curve sections, and the shape of each relaxation curve section is calculated separately. As a result, data (specifically, a clothoid coefficient representing a clothoid curve) related to a shape connecting two sections with a constant degree of flexion appropriately and smoothly can be calculated.

  S1 (B1) ... road position data acquisition step (means), S2 (B2) ... flexure degree acquisition step (means), S3 (B3) ... flexion degree constant section identification step (means), S4 (B4) ... constant flexion degree Acquisition step (means), S5 (B5) ... end point position determination step (means), S6 (B6) ... relaxation curve section shape calculation step (means), DB ... road shape database

Claims (9)

A road position data acquisition step for acquiring a plurality of position data on the road;
A bending degree acquisition step of acquiring the bending degree of the road at a point corresponding to the position data;
Based on the change state of the bending degree with respect to the progress of the point corresponding to the position data, the bending degree constant section identifying step for identifying the bending degree constant section in which the bending degree is constant;
A constant bending degree acquisition step of acquiring a constant bending degree of the bending degree constant section corresponding to the curve section of the road;
An end point position determining step for determining a position of an end point of the constant degree of bending section corresponding to the curve section of the road;
A road shape data creation method comprising: In the road shape data creation method according to claim 1,
The bending degree acquisition step includes
Based on the position data, determine the first point, the second point, and the third point on the road,
A first vertical bisector of a line segment having both ends of the first point and the second point, and a second vertical bisector of a line segment having both ends of the second point and the third point Operate,
A road shape data creation method for calculating the bending degree at the second point based on an intersection of the first vertical bisector and the second vertical bisector. In the road shape data creation method according to claim 1 or claim 2,
The bending degree constant section identifying step includes:
A road that identifies a section in which the ratio of the difference in the degree of bending at the two points relative to the distance between the two points corresponding to the two adjacent position data is equal to or less than a predetermined value as the constant degree of bending section Shape data creation method. In the road shape data creation method according to claim 1 or claim 2,
The bending degree constant section identifying step includes:
The section where the section distance is a predetermined distance or more and the difference between the maximum value and the minimum value of the bending degree at a plurality of points corresponding to the continuous position data included in the section is a predetermined value or less. Road shape data creation method for identifying a section with a constant degree of flexion. The road shape data creation method according to any one of claims 1 to 4,
Each of the end point positions on the side connecting the relaxation curve sections connecting the two adjacent fixed curvature sections identified by the constant curvature section identification step with the relaxation curve sections of the two fixed curvature sections And the road shape data creation method provided with the relaxation curve shape calculation process calculated based on the said fixed bending degree of each of the said 2 bending degree fixed area. In the road shape data creation method according to claim 5,
The relaxation curve shape calculation step includes:
A road shape data creation method for calculating on the assumption that the shape of the relaxation curve section is a clothoid curve. In the road shape data creation method according to claim 5 or 6,
The relaxation curve shape calculation step includes:
When the adjacent two bending degree constant sections have different bending directions, an intermediate position where the bending degree becomes a value corresponding to a straight section in a section connecting the two constant bending degree sections is determined.
The end point position on the side connecting the shape of the first relaxation curve section that is continuous to the first bending degree constant section of the two bending degree constant sections to the first relaxation curve section of the first bending degree constant section, While calculating based on the constant bending degree of the first bending degree constant section and the intermediate position,
The end point position on the side connecting the shape of the second relaxation curve section that continues to the second bending degree constant section of the two constant bending degree sections to the second relaxation curve section of the second bending degree constant section, Based on the constant bending degree of the second bending degree constant section and the intermediate position,
A road shape data creation method for calculating a shape of the relaxation curve section connecting the two sections with a constant degree of bending to a shape obtained by connecting the first and second relaxation curve sections at the intermediate position. Road position data acquisition means for acquiring a plurality of position data on the road;
Bend degree acquisition means for acquiring the bend degree of the road at a point corresponding to the position data;
A bending degree constant section identifying means for identifying a bending degree constant section in which the bending degree is constant based on a change state of the bending degree with respect to the progress of a point corresponding to the position data;
A constant bending degree acquisition means for acquiring a constant bending degree of the bending degree constant section corresponding to the curve section of the road;
End point position determining means for determining the position of the end point of the constant degree of bending section corresponding to the curve section of the road;
A road shape data acquisition device. The road shape data acquisition device according to claim 8,
Each of the end point positions on the side connecting the two relaxation degree curve sections connecting the two constant bending degree sections identified by the constant bending degree section identification means to the relaxation curve section of the two constant bending degree sections And a road shape data acquisition device comprising a relaxation curve shape calculation means for calculating based on the constant bending degree of each of the two constant bending degree sections.

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