Driving assistance device, driving assistance method, and storage medium
A driving assistance device executes dual-side braking steering avoidance control for forcibly decelerating a target vehicle by applying braking forces to wheels on both sides of the target vehicle and forcibly turning the target vehicle to swerve around an object in a case where a turning amount increase request condition is not satisfied. When forcibly turning the target vehicle rightward or leftward by collision avoidance control to swerve around the object in a case where the turning amount increase request condition is satisfied, the driving assistance device executes single-side braking steering avoidance control for forcibly decelerating the target vehicle by applying a braking force only to a right or left wheel of the target vehicle and forcibly turning the target vehicle to swerve around the object.
1 . A driving assistance device comprising electronic control unit configured to execute collision avoidance control for avoiding collision between a target vehicle and an object ahead of the target vehicle by decelerating the target vehicle and turning the target vehicle to swerve around the object, wherein the electronic control unit is configured to:
execute, as the collision avoidance control, dual-side braking steering avoidance control for decelerating the target vehicle by applying equal or substantially equal braking forces to wheels on both sides of the target vehicle and turning the target vehicle to swerve around the object in a case where a turning amount increase request condition that a request is made to increase a turning rate that is a turning amount of the target vehicle relative to an amount of change in a steering angle of the target vehicle when the target vehicle is turned by the collision avoidance control is not satisfied, the substantially equal braking forces including a difference that falls within a range smaller than a predetermined value;
when turning the target vehicle rightward by the collision avoidance control to swerve around the object in a case where the turning amount increase request condition is satisfied, execute, as the collision avoidance control, single-side braking steering avoidance control for decelerating the target vehicle by applying, to a right wheel of the target vehicle, a braking force larger than a braking force applied to a left wheel, and turning the target vehicle to swerve around the object; and
when turning the target vehicle leftward by the collision avoidance control to swerve around the object in the case where the turning amount increase request condition is satisfied, execute, as the collision avoidance control, the single-side braking steering avoidance control for decelerating the target vehicle by applying, to the left wheel of the target vehicle, a braking force larger than a braking force applied to the right wheel, and turning the target vehicle to swerve around the object, wherein
the turning amount increase request condition is satisfied when an overlap rate between the target vehicle and the object is higher than a predetermined value, the overlap rate corresponding to a value indicating a rate of overlap between a width of the target vehicle and a width of the object,
in a case where a steering avoidance request condition is not satisfied, the electronic control unit is configured to execute braking avoidance control, and in a case where the steering avoidance request is satisfied, the electronic control unit is configured to execute steering avoidance control, and
in a case where the steering avoidance request condition is satisfied and a steering avoidance prohibition condition is satisfied, the electronic control unit is configured to not execute the steering avoidance control and execute the braking avoidance control.
2 . The driving assistance device according to claim 1 , wherein the turning amount increase request condition is satisfied when the target vehicle is not expected to swerve around the object by the dual-side braking steering avoidance control.
3 . The driving assistance device according to claim 1 , wherein the turning amount increase request condition is satisfied when the turning rate required to swerve the target vehicle around the object is higher than a predetermined turning rate.
4 . The driving assistance device according to claim 3 , wherein the predetermined turning rate is a maximum value of the turning rate that is achievable by the dual-side braking steering avoidance control.
5 . The driving assistance device according to claim 1 , wherein the turning amount increase request condition is satisfied when the turning amount of the target vehicle that is achievable by the dual-side braking steering avoidance control is smaller than the turning amount of the target vehicle that is required to swerve the target vehicle around the object.
6 . The driving assistance device according to claim 1 , wherein the turning amount increase request condition is satisfied when a relative speed between the target vehicle and the object is higher than a predetermined speed.
7 . The driving assistance device according to claim 1 , wherein:
the collision avoidance control includes the braking avoidance control for avoiding the collision between the target vehicle and the object by decelerating and stopping the target vehicle without turning the target vehicle; and
the electronic control unit is configured to:
execute the braking avoidance control in a case where a deceleration of the target vehicle when the braking avoidance control is executed is equal to or lower than a predetermined deceleration; and
execute the dual-side braking steering avoidance control or the single-side braking steering avoidance control in a case where the deceleration of the target vehicle when the braking avoidance control is executed is higher than the predetermined deceleration.
8 . The driving assistance device according to claim 7 , wherein the electronic control unit is configured to execute, in a case in which a second object is present in a space beside the object and a target traveling path is set through the space where the second object is present and the target vehicle travels along the target traveling path, the braking avoidance control to avoid collision with the second object instead of the single-side braking steering avoidance control or the dual-side braking steering avoidance control even if the steering avoidance request condition is satisfied.
9 . The driving assistance device according to claim 1 , wherein the electronic control unit is configured to execute neither the dual-side braking steering avoidance control nor the single-side braking steering avoidance control in a case where the target vehicle has a possibility of colliding with an object other than the object when the dual-side braking steering avoidance control or the single-side braking steering avoidance control is executed.
10 . The driving assistance device according to claim 1 , wherein the steering avoidance request condition is at least one of:
a condition in which the deceleration of the target vehicle when the braking avoidance control is executed is higher than a predetermined deceleration,
a condition in which a current target vehicle speed is higher than a predetermined vehicle speed, or
a condition in which a steering avoidance limit period associated with the current target vehicle speed is shorter than a braking avoidance limit period associated with the current target vehicle speed.
11 . A driving assistance method for avoiding collision between a target vehicle and an object ahead of the target vehicle by executing collision avoidance control for decelerating the target vehicle and turning the target vehicle to swerve around the object, the driving assistance method comprising:
executing, as the collision avoidance control, dual-side braking steering avoidance control for decelerating the target vehicle by applying equal or substantially equal braking forces to wheels on both sides of the target vehicle and turning the target vehicle to swerve around the object in a case where a turning amount increase request condition that a request is made to increase a turning rate that is a turning amount of the target vehicle relative to an amount of change in a steering angle of the target vehicle when the target vehicle is turned by the collision avoidance control is not satisfied, the substantially equal braking forces including a difference that falls within a range smaller than a predetermined value;
when turning the target vehicle rightward by the collision avoidance control to swerve around the object in a case where the turning amount increase request condition is satisfied, executing, as the collision avoidance control, single-side braking steering avoidance control for decelerating the target vehicle by applying, to a right wheel of the target vehicle, a braking force larger than a braking force applied to a left wheel, and turning the target vehicle to swerve around the object; and
when turning the target vehicle leftward by the collision avoidance control to swerve around the object in the case where the turning amount increase request condition is satisfied, executing, as the collision avoidance control, the single-side braking steering avoidance control for decelerating the target vehicle by applying, to the left wheel of the target vehicle, a braking force larger than a braking force applied to the right wheel, and turning the target vehicle to swerve around the object, wherein
the turning amount increase request condition is satisfied when an overlap rate between the target vehicle and the object is higher than a predetermined value, the overlap rate corresponding to a value indicating a rate of overlap between a width of the target vehicle and a width of the object,
in a case where a steering avoidance request condition is not satisfied, executing braking avoidance control, and in a case where the steering avoidance request is satisfied, executing steering avoidance control, and
in a case where the steering avoidance request condition is satisfied and a steering avoidance prohibition condition is satisfied, not executing the steering avoidance control and executing the braking avoidance control.
12 . The driving assistance method according to claim 11 , wherein the turning amount increase request condition is satisfied when the target vehicle is not expected to swerve around the object by the dual-side braking steering avoidance control.
13 . The driving assistance method according to claim 11 , wherein the turning amount increase request condition is satisfied when the turning rate required to swerve the target vehicle around the object is higher than a predetermined turning rate.
14 . The driving assistance method according to claim 13 , wherein the predetermined turning rate is a maximum value of the turning rate that is achievable by the dual-side braking steering avoidance control.
15 . The driving assistance method according to claim 11 , wherein the turning amount increase request condition is satisfied when the turning amount of the target vehicle that is achievable by the dual-side braking steering avoidance control is smaller than the turning amount of the target vehicle that is required to swerve the target vehicle around the object.
16 . The driving assistance method according to claim 11 , wherein the turning amount increase request condition is satisfied when a relative speed between the target vehicle and the object is higher than a predetermined speed.
17 . The driving assistance method according to claim 11 , wherein:
the collision avoidance control includes the braking avoidance control for avoiding the collision between the target vehicle and the object by decelerating and stopping the target vehicle without turning the target vehicle; and
the driving assistance method includes:
executing the braking avoidance control in a case where a deceleration of the target vehicle when the braking avoidance control is executed is equal to or lower than a predetermined deceleration; and
executing the dual-side braking steering avoidance control or the single-side braking steering avoidance control in a case where the deceleration of the target vehicle when the braking avoidance control is executed is higher than the predetermined deceleration.
18 . The driving assistance method according to claim 11 , further comprising executing neither the dual-side braking steering avoidance control nor the single-side braking steering avoidance control in a case where the target vehicle has a possibility of colliding with an object other than the object when the dual-side braking steering avoidance control or the single-side braking steering avoidance control is executed.
19 . A non-transitory storage medium storing instructions that are executable by one or more processors mounted on a vehicle and that cause the one or more processors to perform functions comprising:
executing collision avoidance control for decelerating a target vehicle and turning the target vehicle to swerve around an object ahead of the target vehicle;
executing, as the collision avoidance control, dual-side braking steering avoidance control for decelerating the target vehicle by applying equal or substantially equal braking forces to wheels on both sides of the target vehicle and turning the target vehicle to swerve around the object in a case where a turning amount increase request condition that a request is made to increase a turning rate that is a turning amount of the target vehicle relative to an amount of change in a steering angle of the target vehicle when the target vehicle is turned by the collision avoidance control is not satisfied, the substantially equal braking forces including a difference that falls within a range smaller than a predetermined value;
when turning the target vehicle rightward by the collision avoidance control to swerve around the object in a case where the turning amount increase request condition is satisfied, executing, as the collision avoidance control, single-side braking steering avoidance control for decelerating the target vehicle by applying, to a right wheel of the target vehicle, a braking force larger than a braking force applied to a left wheel, and turning the target vehicle to swerve around the object; and
when turning the target vehicle leftward by the collision avoidance control to swerve around the object in the case where the turning amount increase request condition is satisfied, executing, as the collision avoidance control, the single-side braking steering avoidance control for decelerating the target vehicle by applying, to the left wheel of the target vehicle, a braking force larger than a braking force applied to the right wheel, and turning the target vehicle to swerve around the object, wherein
the turning amount increase request condition is satisfied when an overlap rate between the target vehicle and the object is higher than a predetermined value, the overlap rate corresponding to a value indicating a rate of overlap between a width of the target vehicle and a width of the object,
in a case where a steering avoidance request condition is not satisfied, executing braking avoidance control, and in a case where the steering avoidance request is satisfied, executing steering avoidance control, and
in a case where the steering avoidance request condition is satisfied and a steering avoidance prohibition condition is satisfied, not executing the steering avoidance control and executing the braking avoidance control.