Merge assistance device and merge assistance method

A merge assistance device for assisting merge from an own lane on which an own vehicle travels, to a target lane, the merge assistance device comprising at least one processor configured to implement:

• an own-vehicle position acquisition circuitry for acquiring an own-vehicle position determined by a locator;
• a provisional merge point setting circuitry 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 calculator 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 circuitry which sets a frontward specific attention point on the own lane on a side frontward of the provisional merge point, and sets a rearward specific attention point on the own lane on a side rearward of the provisional merge point;
• a first approximation expression deriving circuitry for deriving a first approximation expression approximating coordinates of the frontward specific attention point and the rearward specific attention point;
• a second approximation expression deriving circuitry 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 estimator 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, wherein
• the attention point setting circuitry
• if a shortest distance from the provisional merge point to the target lane is equal to or greater than a provisional merge point threshold distance, sets, on the side frontward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is smaller than the provisional merge point threshold distance and which is closest to the provisional merge point, as the frontward specific attention point, and sets, on the side rearward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is equal to or greater than the provisional merge point threshold distance and which is closest to the frontward specific attention point, as the rearward specific attention point, and
• if the shortest distance from the provisional merge point to the target lane is smaller than the provisional merge point threshold distance, sets, on a side rearward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is equal to or greater than the provisional merge point threshold distance and which is closest to the provisional merge point, as the rearward specific attention point, and sets, on the side frontward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is smaller than the provisional merge point threshold distance and which is closest to the rearward specific attention point, as the frontward specific attention point.

A merge assistance method for assisting merge from an own lane on which an own vehicle travels, to a target lane, the merge assistance method comprising:

• acquiring an own-vehicle position determined by a locator;
• 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;
• calculating a lane-to-lane distance from each point on the own lane to each point on the target lane;
• 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 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 calculating;
• deriving a first approximation expression approximating coordinates of the one or more frontward attention points and the one or more rearward attention points;
• 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
• 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 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.

A merge assistance method for assisting merge from an own lane on which an own vehicle travels, to a target lane, the merge assistance method comprising:

• acquiring an own-vehicle position determined by a locator;
• 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;
• calculating a lane-to-lane distance from each point on the own lane to each point on the target lane;
• setting a frontward specific attention point on the own lane on a side frontward of the provisional merge point, and setting a rearward specific attention point on the own lane on a side rearward of the provisional merge point;
• deriving a first approximation expression approximating coordinates of the frontward specific attention point and the rearward specific attention point;
• 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
• 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, 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, wherein
• in the attention point setting,
• if a shortest distance from the provisional merge point to the target lane is equal to or greater than a provisional merge point threshold distance, on the side frontward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is smaller than the provisional merge point threshold distance and which is closest to the provisional merge point, is set as the frontward specific attention point, and on the side rearward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is equal to or greater than the provisional merge point threshold distance and which is closest to the frontward specific attention point, is set as the rearward specific attention point, and
• if the shortest distance from the provisional merge point to the target lane is smaller than the provisional merge point threshold distance, on a side rearward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is equal to or greater than the provisional merge point threshold distance and which is closest to the provisional merge point, is set as the rearward specific attention point, and on the side frontward of the provisional merge point on the own lane, a point at which the lane-to-lane distance is smaller than the provisional merge point threshold distance and which is closest to the rearward specific attention point, is set as the frontward specific attention point.