Merge assistance device and merge assistance method

A merge assistance device of the present disclosure includes: an own-vehicle position acquisition unit for acquiring an own-vehicle position; a provisional merge point setting unit for setting a provisional merge point on an own lane; a lane-to-lane distance calculation unit for calculating a lane-to-lane distance from the own lane to the target lane; an attention point setting unit for setting a frontward attention point and a rearward attention point on the own lane; a first approximation expression deriving unit for deriving a first approximation expression approximating frontward attention points and rearward attention points; a second approximation expression deriving unit for deriving a second approximation expression approximating the target lane; and a merging-possible area start point estimation unit for estimating a merging-possible area start point on the target lane on the basis of an own-lane width, a target-lane width, and the first and second approximation expressions.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to a merge assistance device and a merge assistance method.

2. Description of the Background Art

For putting autonomous driving into practical use, being developed is technology in which the own-vehicle position is determined by a locator and map information relevant to the determined own-vehicle position is utilized to achieve high-level vehicle control.

One example of high-level vehicle control is autonomous merging control in a scene of merging from a merging lane to a main lane. For achieving the autonomous merging control, accurate position information about a merging-possible area start point, e.g., a hatched-marking area, in particular, a hatched-marking area leading end, is needed.Patent Document 1: Japanese Patent No. 4645429

Map information that a locator has includes position information about merge start points. The position information about merge start points is indirectly given as boundaries between section types such as a main lane, a merging lane, a split lane, and a ramp. A boundary at which the section type is switched from a ramp to a merging lane may be considered to be a merge start point.

A merge start point acquired from the map information that the locator has depends on the content of the map that the locator has, and does not necessarily coincide with a merging-possible area start point, e.g., a hatched-marking area leading end on a road. This is because the merge start point may be located frontward of the hatched-marking area leading end or may be located rearward thereof.

Patent Document 1 discloses an on-vehicle device which estimates a merging-possible area start point through image processing such as overhead image conversion using a hatched-marking area image acquired by an on-vehicle camera. However, in the case of estimating the merging-possible area start point through image processing on the hatched-marking area image, error occurs due to the conversion processing, thus causing a problem that estimation accuracy might be insufficient in autonomous merging control.

SUMMARY OF THE DISCLOSURE

The present disclosure has been made to solve the above problem and an object of the present disclosure is to provide a merge assistance device and a merge assistance method for estimating a merging-possible area start point with high accuracy by utilizing map information that a locator has.

A merge assistance device according to the present disclosure is for assisting merge from an own lane on which an own vehicle travels, to a target lane, and includes: an own-vehicle position acquisition unit for acquiring an own-vehicle position determined by a locator; a provisional merge point setting unit for setting a provisional merge point on the own lane on the basis of coordinate information of the own lane and the target lane included in map information stored in a map information database; a lane-to-lane distance calculation unit for calculating a lane-to-lane distance from each point on the own lane to each point on the target lane; an attention point setting unit which, on the basis of a provisional merge point lane-to-lane distance from the provisional merge point to the target lane calculated by the lane-to-lane distance calculation unit, sets one or more frontward attention points on the own lane on a side frontward of the provisional merge point and sets one or more rearward attention points on the own lane on a side rearward of the provisional merge point; a first approximation expression deriving unit for deriving a first approximation expression approximating coordinates of the one or more frontward attention points and the one or more rearward attention points; a second approximation expression deriving unit for deriving a second approximation expression approximating coordinates on the target lane including coordinates of a position at a shortest distance from the provisional merge point; and a merging-possible area start point estimation unit which, on the basis of an own-lane width and a target-lane width included in the map information, and the first approximation expression and the second approximation expression, estimates, on the target lane, a merging-possible area start point which is a start point of an area where the own vehicle becomes able to merge from the own lane to the target lane.

A merge assistance method according to the present disclosure is for assisting merge from an own lane on which an own vehicle travels, to a target lane, and includes: an own-vehicle position acquisition step of acquiring an own-vehicle position determined by a locator; a provisional merge point setting step of setting a provisional merge point on the own lane on the basis of coordinate information of the own lane and the target lane included in map information stored in a map information database; a lane-to-lane distance calculation step of calculating a lane-to-lane distance from each point on the own lane to each point on the target lane; an attention point setting step of, on the basis of a provisional merge point lane-to-lane distance from the provisional merge point to the target lane calculated in the lane-to-lane distance calculation step, setting one or more frontward attention points on the own lane on a side frontward of the provisional merge point and setting one or more rearward attention points on the own lane on a side rearward of the provisional merge point; a first approximation expression deriving step of deriving a first approximation expression approximating coordinates of the one or more frontward attention points and the one or more rearward attention points; a second approximation expression deriving step of deriving a second approximation expression approximating coordinates on the target lane including coordinates of a position at a shortest distance from the provisional merge point; and a merging-possible area start point estimation step of, on the basis of an own-lane width and a target-lane width included in the map information, and the first approximation expression and the second approximation expression, estimating, on the target lane, a merging-possible area start point which is a start point of an area where the own vehicle becomes able to merge from the own lane to the target lane.

In the merge assistance device and the merge assistance method according to the present disclosure, using the provisional merge point acquired from map information that the locator has, frontward attention points and rearward attention points are set on the own lane on the basis of the lane-to-lane distance from the provisional merge point to the target lane. Using the frontward attention points and the rearward attention points, the first approximation expression representing the own lane is derived. The second approximation expression is derived by approximating coordinates on the target lane including coordinates of the position at the shortest distance from the provisional merge point. The merging-possible area start point is estimated on the basis of the first approximation expression and the second approximation expression. This provides an effect of obtaining a merge assistance device and a merge assistance method that can estimate the merging-possible area start point with high accuracy.

First Embodiment

FIG.1is a function block diagram showing the configuration of a merge assistance device100according to the first embodiment of the present disclosure. The merge assistance device100shown inFIG.1includes an own-vehicle position acquisition unit101, a provisional merge point setting unit102, a lane-to-lane distance calculation unit103, an attention point setting unit104, an approximation expression deriving unit105, a merging-possible area start point estimation unit106, and a vehicle control unit110. In the following description, a case of mentioning “coordinates” may mean a “point” represented by the “coordinates”, and a case of mentioning a “point” may mean “coordinates” corresponding to the “point”.

From a locator101aprovided outside the merge assistance device100, the own-vehicle position acquisition unit101acquires an own-vehicle position, and map information relevant to the own-vehicle position and stored in a map information database101binside the locator101a. InFIG.1, the map information database101bis provided inside the locator101a. However, the map information database101bmay be provided outside the locator101a, or may be provided inside the merge assistance device100.

The own-vehicle position acquisition unit101outputs information such as the own-vehicle position and the map information acquired from the locator101a, to the provisional merge point setting unit102.

The locator101ais for specifying the position of the own vehicle, and determines the own-vehicle position by using a global navigation satellite system (GNSS) receiver, for example. The own-vehicle position may be detected using a device such as an inertial navigation device.

The map information database101binside the locator101astores map information. The map information includes at least a section type, coordinate information of an own lane1, coordinate information of a target lane2, the positional relationship between the own lane1and the target lane2, an own-lane width, a target-lane width, and the like. The coordinate information of the own lane1, the coordinate information of the target lane2, and the like are provided at certain intervals to the map information.

The locator101adetects the present position of the own vehicle on the map on the basis of positioning data for the own-vehicle position acquired by the GNSS receiver and map information around the own-vehicle position stored in the map information database101b, for example, and outputs the detected present position to the own-vehicle position acquisition unit101.

The provisional merge point setting unit102sets a provisional merge point4on the own lane1on the basis of the coordinate information of the own lane1and the target lane2included in the map information stored in the map information database101b. As an example of the provisional merge point4, as shown inFIG.3, coordinates of a section-type switchover point at which the section type is switched from ramp to merge may be calculated, and the calculated coordinates may be set as the provisional merge point4.

The lane-to-lane distance calculation unit103calculates a distance from each point on the own lane1to each point on the target lane2, i.e., a lane-to-lane distance. The lane-to-lane distance calculation unit103can also calculate a lane-to-lane distance from each attention point on the own lane1to each point on the target lane2. In particular, the lane-to-lane distance from the provisional merge point4to the target lane2is calculated as a provisional merge point lane-to-lane distance LM. A method for calculating the provisional merge point lane-to-lane distance LM will be described later.

The attention point setting unit104sets one or more frontward attention points5on the own lane1on the side frontward of the provisional merge point4, on the basis of the provisional merge point lane-to-lane distance LM outputted from the lane-to-lane distance calculation unit103. The attention point setting unit104sets one or more rearward attention points6on the own lane1on the side rearward of the provisional merge point4.FIG.3shows examples of the frontward attention points5and the rearward attention points6. A method for setting the frontward attention points5and the rearward attention points6will be described later.

The approximation expression deriving unit105includes a first approximation expression deriving unit105aand a second approximation expression deriving unit105b. The first approximation expression deriving unit105aand the second approximation expression deriving unit105bmay be integrated as one unit.

The approximation expression deriving unit105derives an approximation expression approximating coordinates on the own lane1or the target lane2. The first approximation expression deriving unit105ain the approximation expression deriving unit105derives a first approximation expression approximating coordinates of one or more frontward attention points and one or more rearward attention points. That is, the first approximation expression represents an approximation of the own lane1. On the other hand, the second approximation expression deriving unit105bin the approximation expression deriving unit105derives a second approximation expression approximating coordinates on the target lane2including coordinates of the position at the shortest distance from the provisional merge point4. That is, the second approximation expression represents an approximation of the target lane2near the provisional merge point4on the own lane1. The details of deriving for the approximation expressions and the like will be described later.

The merging-possible area start point estimation unit106estimates, on the target lane2, a merging-possible area start point which is a start point of an area where the own vehicle becomes able to merge from the own lane1which is the merging lane to the target lane2, on the basis of the own-lane width, the target-lane width, the first approximation expression, and the second approximation expression.

The vehicle control unit110controls traveling of the own vehicle toward the merging-possible area start point on the target lane2estimated by the merging-possible area start point estimation unit106.

The components of the merge assistance device100according to the first embodiment and the locator101aare as described above.

Next, operation of the merge assistance device100according to the first embodiment, i.e., a merge assistance method, will be described with reference toFIG.2,FIG.3, andFIG.4.

FIG.2is a flowchart showing the merge assistance method according to the first embodiment,FIG.3schematically shows a merge scene in the merge assistance method according to the first embodiment, andFIG.4schematically shows a method for estimating the merging-possible area start point in the merge assistance method according to the first embodiment.

Hereinafter, with reference to the flowchart inFIG.2, the merge assistance method according to the first embodiment will be described. First, in step S101, the own-vehicle position is acquired by the locator101adetermining the own-vehicle position. The information of the own-vehicle position detected by the locator101ais outputted to the own-vehicle position acquisition unit101.

In step S102, from the map information stored in the map information database101binside the locator101a, coordinates of a section-type switchover point at which the section type is switched from ramp to merge in map information around the own-vehicle position are calculated and set as the provisional merge point4. This setting method for the provisional merge point4is merely an example. Another setting method may be used as long as the provisional merge point4is set on the own lane1on the basis of coordinate information of the own lane1on which the own vehicle is traveling and the target lane2, included in the map information stored in the map information database101b.

In step S103, on the basis of the provisional merge point4set in step S102, the coordinate information of the target lane2included in the map information, and the positional relationship between the own lane1and the target lane2, the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2is calculated. For example, as shown inFIG.3, in a case where the target lane2is almost straight, the length of a perpendicular from the provisional merge point4to the target lane2on a plan view of the map may be calculated as the provisional merge point lane-to-lane distance LM. Alternatively, the shortest distance from the provisional merge point4on the own lane1to the target lane2may be calculated as the provisional merge point lane-to-lane distance LM.

In step S104, on the basis of the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2, a number N of frontward attention points5and a number M of rearward attention points6with respect to the provisional merge point4are determined. That is, on the basis of the provisional merge point lane-to-lane distance LM outputted from the lane-to-lane distance calculation unit103, the attention point setting unit104sets N frontward attention points5at intervals on the own lane1on the side frontward of the provisional merge point4. In addition, the attention point setting unit104sets M rearward attention points6at intervals on the own lane1on the side rearward of the provisional merge point4. As the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2becomes longer, the numbers of the attention points proportionally increase. It is desirable that the intervals of the attention points are constant, but the intervals may not necessarily be constant.

The number N of the frontward attention points5may be one or more, i.e., N≥1. The number M of the rearward attention points6may be one or more, i.e., M≥1. For example, in the case ofFIG.3, if the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2is great, a hatched-marking area leading end (not shown) is considered to be present frontward of the provisional merge point4, and thus a large number of frontward attention points5are set. That is, the number N of the frontward attention points5is set to 4, and the number M of the rearward attention points6is set to 1.

In step S105, the first approximation expression representing the own lane1near the provisional merge point4is derived using the coordinate information of the frontward attention point5and the rearward attention point6included in the coordinate information of the own lane1. Deriving for the first approximation expression is performed by the first approximation expression deriving unit105a.

In step S106, the second approximation expression for the target lane2is derived by approximating coordinates on the target lane2including the coordinates of the position at the shortest distance from the provisional merge point4. Deriving for the second approximation expression is performed by the second approximation expression deriving unit105b.

In step S107, among points at which a lane-to-lane distance LS which is a distance between a point on the second approximation expression representing the target lane2and a point on the first approximation expression representing the own lane1is equal to or smaller than a lane-to-lane threshold distance, a point closest to the own-vehicle position, on the target lane2, is estimated as a merging-possible area start point. The lane-to-lane threshold distance is set to an appropriate value in accordance with the own-lane width and the target-lane width.

In the subsequent process from step S105, as shown inFIG.4, the target lane2may be approximated as a straight line (second approximation expression), and with the target lane2defined as x axis and an axis orthogonal to the x axis defined as y axis, the approximation expression (first approximation expression) for the own lane1may be represented as a function f, i.e., y=f(x). InFIG.4, the y-axis-direction interval between the first approximation expression and the second approximation expression corresponds to the lane-to-lane distance LS. Among points on the target lane2at which the lane-to-lane distance LS is equal to or smaller than the lane-to-lane threshold distance, a point closest to the own-vehicle position is estimated as the merging-possible area start point.

The vehicle control unit110outputs a control quantity for the own vehicle on the basis of the merging-possible area start point on the target lane2estimated by the merging-possible area start point estimation unit106. For example, in a case of using vehicle control technology such as model prediction control, vehicle control is performed with a constraint condition set so as not to perform lane change before the merging-possible area start point.

Effects of First Embodiment

As described above, in the merge assistance device and the merge assistance method according to the first embodiment, using the provisional merge point4which is a merge start point acquired from map information in the locator101a, the frontward attention point5and the rearward attention point6are set on the own lane1on the basis of the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2. Using the attention points, the first approximation expression representing the own lane1near the provisional merge point4is derived, and further, the second approximation expression is derived by approximating the target lane2including the coordinates of the position at the shortest distance from the provisional merge point4. A point on the target lane2at which the lane-to-lane distance LS between the own lane1and the target lane2is equal to or smaller than the lane-to-lane threshold distance is estimated as the merging-possible area start point. This provides an effect of obtaining a merge assistance device and a merge assistance method that enable highly accurate estimation for the merging-possible area start point when the own vehicle merges from the own lane1to the target lane2.

Second Embodiment

A merge assistance device used in a merge assistance method according to the second embodiment of the present disclosure is the same as that in the first embodiment, and therefore description of the merge assistance device is omitted. With reference toFIG.5andFIG.6, the merge assistance method according to the second embodiment will be described.

FIG.5is a flowchart showing the merge assistance method according to the second embodiment, andFIG.6schematically shows a merge scene of the own vehicle merging from the own lane1to the target lane2in the merge assistance device according to the second embodiment. Hereinafter, with reference to the flowchart inFIG.5, the merge assistance method according to the second embodiment will be described.

Processing in steps S201to S203is the same as the processing in steps S101to S103in the flowchart inFIG.2, and therefore description thereof is omitted.

In step S204, whether or not the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2is equal to or greater than a provisional merge point threshold distance, is determined.

If the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2is equal to or greater than the provisional merge point threshold distance, i.e., in the case of Yes in step S204, in step S205, a lane-to-lane distance L1to the target lane2is calculated for coordinates on the own lane1on the side frontward of the provisional merge point4, on the basis of the provisional merge point4set in step S202, the coordinate information of the target lane2included in the map information, and the positional relationship between the own lane1and the target lane2.

In performing step S205, it is assumed that the lane-to-lane distance L1monotonically decreases as the coordinates on the own lane1advances frontward from the provisional merge point4.

In step S206, on the own lane1on the side frontward of the provisional merge point4, a point N1closest to the provisional merge point4among points on the own lane1at which the lane-to-lane distance L1from coordinates on the own lane1to the target lane2is smaller than the lane-to-lane threshold distance, is set as a frontward specific attention point. For example, in the merge scene shown inFIG.6, the point N1which is the frontward specific attention point is the second frontward attention point5counted frontward from the provisional merge point4. Further, on the own lane1on the side rearward of the point N1, a point M1closest to the point N1which is the frontward specific attention point among points on the own lane1at which the lane-to-lane distance L1from the own lane1to the target lane2is equal to or greater than the lane-to-lane threshold distance, is set as a rearward specific attention point.

In step S207, using the coordinate information of the frontward specific attention point (N1) and the rearward specific attention point (M1) set in step S206, the first approximation expression which is an approximation expression for the own lane1near the provisional merge point4is derived.

In step S208, a second approximation expression is derived by approximating coordinates on the target lane2including coordinates of the position at the shortest distance from the provisional merge point4.

In step S209, among points at which the distance between a point on the second approximation expression representing the target lane2and a point on the first approximation expression representing the own lane1, i.e., the lane-to-lane distance LS, is equal to or smaller than the lane-to-lane threshold distance, a point closest to the own-vehicle position, on the target lane2, is estimated as a merging-possible area start point.

On the other hand, in step S204, if the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2is smaller than the provisional merge point threshold distance, i.e., in the case of No in step S204, in step S220, a lane-to-lane distance L2from the own lane1to the target lane2is calculated for coordinates on the own lane1on the side rearward of the provisional merge point4, on the basis of the provisional merge point4set in step S202, the coordinate information of the target lane2included in the map information, and the positional relationship between the own lane1and the target lane2.

In performing step S220, it is assumed that the lane-to-lane distance L2monotonously increases as the coordinates on the own lane1become away rearward from the provisional merge point4. Here, targets for which the lane-to-lane distance L2is calculated are coordinates on the own lane1at which the lane-to-lane distance L2is equal to or greater than the provisional merge point threshold distance.

In step S221, on the own lane1on the side frontward of the provisional merge point4, a point N2closest to the provisional merge point4among points at which the lane-to-lane distance L2from the own lane1to the target lane2is smaller than the provisional merge point threshold distance, is set as a frontward specific attention point. In addition, on the side rearward of the point N2, a point M2closest to the point N2among points at which the lane-to-lane distance L2between the own lane1and the target lane2is equal to or greater than the provisional merge point threshold distance, is set as a rearward specific attention point.

In processing after step S221, the processing in steps S207to S209described above is performed.

In the subsequent processing from step S207, as shown inFIG.4, the target lane2may be approximated as a straight line, and with the target lane2defined as x axis and an axis orthogonal to the x axis defined as y axis, the approximation expression for the own lane1may be represented as a function f, i.e., y=f (x).

The vehicle control unit110outputs a control quantity for the own vehicle on the basis of the merging-possible area start point estimated by the merging-possible area start point estimation unit106. For example, in a case of using vehicle control technology such as model prediction control, vehicle control is performed with a constraint condition set so as not to perform lane change before the merging-possible area start point.

The merge assistance method according to the second embodiment is as described above.

Effects of Second Embodiment

As described above, in the merge assistance method according to the second embodiment, using a merge start point acquired from the map information in the locator, i.e., the provisional merge point4, on the basis of the provisional merge point lane-to-lane distance LM from the provisional merge point4to the target lane2and the provisional merge point threshold distance, the frontward specific attention point and the rearward specific attention point are set on the own lane1. Using the coordinates of the frontward specific attention point and the rearward specific attention point, the first approximation expression representing the own lane1near the provisional merge point4is derived, and the second approximation expression approximating the target lane2including the coordinates of the position at the shortest distance from the provisional merge point4is derived. Among points on the target lane2at which the lane-to-lane distance between the own lane1and the target lane2is equal to or smaller than the lane-to-lane threshold distance, a point closest to the own-vehicle position is estimated as the merging-possible area start point. This provides an effect of obtaining a merge assistance method that enables highly accurate estimation for the merging-possible area start point when the own vehicle merges from the own lane1to the target lane2.

Third Embodiment

FIG.7is a function block diagram showing the configuration of a merge assistance device200according to the third embodiment of the present disclosure. The merge assistance device200shown inFIG.7further includes a merging-possible area start point correction unit107in addition to the configuration of the merge assistance device100according to the first embodiment. Description of the same components as those in the merge assistance device100according to the first embodiment is omitted.

The merging-possible area start point correction unit107corrects a distance (hereinafter, referred to as start point distance LB) from the provisional merge point4to the merging-possible area start point estimated by the merging-possible area start point estimation unit106, so that the start point distance LB becomes equal to a first start point threshold distance or a second start point threshold distance determined on the basis of a section ID of a road outputted from the locator101a, in accordance with a condition. Then, the merging-possible area start point correction unit107outputs the merging-possible area start point after the correction (hereinafter, referred to as corrected merging-possible area start point), to the vehicle control unit110.

The first start point threshold distance and the second start point threshold distance may be set to values different among maps specified by section IDs of roads.

With reference to a flowchart inFIG.8, a merge assistance method according to the third embodiment will be described. The flowchart inFIG.8shows operations after the step in which the merging-possible area start point is estimated by the merge assistance method according to the first or second embodiment.

In step S301, whether the estimated merging-possible area start point on the target lane2is present frontward or rearward of the provisional merge point4, is determined. If the merging-possible area start point is present frontward of the provisional merge point4, i.e., in the case of Yes in step S301, in step S302, whether or not the start point distance LB from the provisional merge point4to the merging-possible area start point is equal to or smaller than the first start point threshold distance, is determined. The first start point threshold distance may be variable in accordance with the section ID of the road outputted from the locator101a, or may be set separately.

If the start point distance LB from the provisional merge point4to the merging-possible area start point is greater than the first start point threshold distance, i.e., in the case of No in step S302, in step S303, the merging-possible area start point is corrected to a point on the target lane2on the side frontward of the provisional merge point4, at which the start point distance LB from the provisional merge point4to the merging-possible area start point is equal to the first start point threshold distance, as the corrected merging-possible area start point. On the other hand, if the start point distance LB from the provisional merge point4to the merging-possible area start point is equal to or smaller than the first start point threshold distance, i.e., in the case of Yes in step S302, the merging-possible area start point estimated by the merging-possible area start point estimation unit106is used.

If the merging-possible area start point is not present frontward of the provisional merge point4, i.e., in the case of No in step S301, in step S304, whether or not the start point distance LB from the provisional merge point4to the merging-possible area start point is equal to or smaller than the second start point threshold distance, is determined. The second start point threshold distance may be variable in accordance with the section ID of the road outputted from the locator101a, or may be set separately.

If the start point distance LB from the provisional merge point4to the merging-possible area start point is greater than the second start point threshold distance, i.e., in the case of No in step S304, in step S305, the merging-possible area start point is corrected to a point on the target lane2on the side rearward of the provisional merge point4, at which the start point distance LB from the provisional merge point4to the merging-possible area start point is equal to the second start point threshold distance, as the corrected merging-possible area start point. On the other hand, if the start point distance LB from the provisional merge point4to the merging-possible area start point is equal to or smaller than the second start point threshold distance, i.e., in the case of Yes in step S304, the merging-possible area start point estimated by the merging-possible area start point estimation unit106is used.

Effects of Third Embodiment

As described above, in the merge assistance device200and the merge assistance method according to the third embodiment, if the start point distance LB from the provisional merge point4acquired from the map information in the locator101ato the merging-possible area start point estimated in the first or second embodiment is greater than the first start point threshold distance or the second start point threshold distance, correction is performed so that a point away from the provisional merge point4by the first start point threshold distance or the second start point threshold distance becomes the corrected merging-possible area start point. This provides an effect of obtaining a merge assistance device and a merge assistance method in which, for example, even in a case where inaccurate information is included in the map information outputted from the locator101aand therefore the merging-possible area start point estimated by the merging-possible area start point estimation unit106has an abnormal value, the corrected merging-possible area start point can be used, thus enhancing the possibility that autonomous merging control can be performed.

Fourth Embodiment

FIG.9is a function block diagram showing the configuration of a merge assistance device300according to the fourth embodiment of the present disclosure. The merge assistance device300shown inFIG.9further includes a hatched-marking detection unit108in addition to the configuration of the merge assistance device200according to the third embodiment. Description of the same components as those in the merge assistance device according to the first or third embodiment is omitted.

The hatched-marking detection unit108outputs hatched-marking area information obtained on the basis of image information acquired by an on-vehicle front camera (not shown), to the merging-possible area start point correction unit107. The hatched-marking area information includes information about a hatched-marking area leading end.

With reference to a flowchart shown inFIG.10, operations of the merging-possible area start point correction unit107and the hatched-marking detection unit108will be described. The flowchart inFIG.10shows operations after the step in which the merging-possible area start point is estimated or corrected by the merge assistance method according to the third embodiment.

In step S401, on the basis of the hatched-marking area information detected by the hatched-marking detection unit108, the merging-possible area start point correction unit107determines whether the merging-possible area start point is located frontward or rearward of the hatched-marking area leading end.

If the merging-possible area start point is located frontward of the hatched-marking area leading end, i.e., in the case of Yes in step S401, in step S402, whether or not a hatched-marking distance LZ from the hatched-marking area leading end to the merging-possible area start point is equal to or smaller than a hatched-marking threshold distance, is determined.

If the hatched-marking distance LZ from the hatched-marking area leading end to the merging-possible area start point is equal to or smaller than the hatched-marking threshold distance, i.e., in the case of Yes in step S402, the corrected merging-possible area start point corrected by the merging-possible area start point correction unit107is used. In a case where the merging-possible area start point is not corrected by the merging-possible area start point correction unit107, the merging-possible area start point estimated by the merging-possible area start point estimation unit106is used.

If the merging-possible area start point is not located frontward of the hatched-marking area leading end, i.e., in the case of No in step S401, or if the hatched-marking distance LZ from the hatched-marking area leading end to the merging-possible area start point is greater than the hatched-marking threshold distance, i.e., in the case of No in step S402, in step S403, the merging-possible area start point is corrected to a point at which the hatched-marking distance LZ from the hatched-marking area leading end to the merging-possible area start point is equal to the hatched-marking threshold distance, as the corrected merging-possible area start point.

Effects of Fourth Embodiment

As described above, in the merge assistance device300and the merge assistance method according to the fourth embodiment, using the hatched-marking area information acquired from image information obtained by an image camera or the like, processing is further performed for the merging-possible area start point or the corrected merging-possible area start point estimated or corrected in the merge assistance method according to the third embodiment, so that, if the hatched-marking distance LZ from the hatched-marking area leading end to the merging-possible area start point is greater than the hatched-marking threshold distance, the merging-possible area start point is corrected to a point on the frontward side at which the hatched-marking distance LZ from the hatched-marking area leading end to the merging-possible area start point is equal to the hatched-marking threshold distance, as the corrected merging-possible area start point. This provides an effect of obtaining a merge assistance device and a merge assistance method in which, for example, even in a case where inaccurate information is included in the map information outputted from the locator101aand therefore the merging-possible area start point estimated by the merging-possible area start point estimation unit106or the corrected merging-possible area start point corrected by the merging-possible area start point correction unit107has an abnormal value, the further corrected merging-possible area start point can be used, thus enhancing the possibility that autonomous merging control can be performed.

In the above description, the configuration in which the functions of components of the merge assistance devices100,200,300according to the first, third, and fourth embodiments are implemented by one of hardware and software, etc., has been described. However, without limitation thereto, some of the components of the merge assistance devices100,200,300according to the first, third, and fourth embodiments may be implemented by dedicated hardware, and the other components may be implemented by software, etc.

For example, as shown in function block diagrams inFIG.11andFIG.12, for some components, the functions thereof may be implemented by a processing circuit50as dedicated hardware, and for the other components, the processing circuit50as a processor51may read and execute a program54, stored in a memory52, for causing a computer or the like to execute a software part of the merge assistance devices100,200,300according to the first, third, and fourth embodiments, thereby implementing the functions of the other components.

Further, as shown inFIG.12, setting data to be used in the function units and the like of the merge assistance devices100,200,300according to the first, third, and fourth embodiments may be installed as a part of software to the memory52from a storage medium53storing the program54for causing a computer or the like to execute a software part of the merge assistance devices100,200,300according to the first, third, and fourth embodiments.

As described above, the merge assistance devices100,200,300according to the first, third, and fourth embodiments can implement the above-described functions by hardware, software, etc., or a combination thereof.

DESCRIPTION OF THE REFERENCE CHARACTERS