Travel controller and travel control method for alerting driver of road edge

1 . A travel control method comprising:

autonomously controlling acceleration, deceleration, and steering of a vehicle; and

while the vehicle is traveling under autonomous control, performing a travel control processing comprising:

performing detection of whether a departure preventer, configured to prevent the vehicle from running off a road, is present on a road on which the vehicle is traveling based on data from a sensor mounted on the vehicle;

when no departure preventer is detected, determining a possibility of the vehicle reaching the road edge based on a comparison between an expected movement amount of the vehicle in a lateral direction until stopping from a current speed of the vehicle, and a lateral distance from the vehicle to the road edge,

when there is a possibility of the vehicle reaching the road edge, notifying a driver of a transition demand demanding transition from the autonomous control to manual control of the vehicle, and, when there is no possibility of the vehicle reaching the road edge, not notifying the driver of the transition demand; and

when a departure preventer is detected, terminating the travel control processing without determining the possibility of the vehicle reaching the road edge and without notifying the driver of the transition demand.

2 . The travel control method according to claim 1 , further comprising:

calculating the expected movement amount of the vehicle in the lateral direction until stopping based on a maximum amount of movement of the vehicle in the lateral direction expected when steering by a steering operation amount not more than a steering operation threshold and decelerating by a predetermined acceleration rate until stopping from the current speed of the vehicle.

3 . The travel control method according to claim 1 , further comprising:

performing detection of whether there is a lane line, demarcating a lane included in the road, based on the data from the sensor, and

when there is a possibility of the vehicle reaching the road edge and no lane line is detected, perform the autonomous stopping control of the vehicle so that the vehicle stops at a road shoulder included in the road.

4 . The travel control method according to claim 3 , wherein performing the autonomous stopping control comprises terminating the autonomous stopping control when a lane line is detected after starting the autonomous stopping control.

5 . A non-transitory computer-readable medium having a computer program for travel control stored therein, the computer program causing a computer mounted on a vehicle to execute a process comprising:

autonomously controlling acceleration, deceleration, and steering of the vehicle; and

while the vehicle is traveling under autonomous control performing a travel control processing comprising:

performing detection of whether a departure preventer, configured to prevent the vehicle from running off a road, is present on a road on which the vehicle is traveling based on data from a sensor mounted on the vehicle;

when no departure preventer is detected, determining a possibility of the vehicle reaching the road edge based on a comparison between an expected movement amount of the vehicle in a lateral direction until stopping from a current speed of the vehicle, and a lateral distance from the vehicle to the road edge,

when there is a possibility of the vehicle reaching the road edge, notifying a driver of a transition demand demanding transition from the autonomous control to manual control of the vehicle, and, when there is no possibility of the vehicle reaching the road edge, not notifying the driver of the transition demand; and

when a departure preventer is detected, terminating the travel control processing without determining the possibility of the vehicle reaching the road edge and without notifying the driver of the transition demand.

6 . The non-transitory computer-readable medium according to claim 5 , wherein the process further comprises:

calculating the expected movement amount of the vehicle in the lateral direction until stopping based on a maximum amount of movement of the vehicle in the lateral direction expected when steering by a steering operation amount not more than a steering operation threshold and decelerating by a predetermined acceleration rate until stopping from the current speed of the vehicle.

7 . The non-transitory computer-readable medium according to claim 5 , wherein the process further comprises:

performing detection of whether there is a lane line, demarcating a lane included in the road, based on the data from the sensor, and

when there is a possibility of the vehicle reaching the road edge and no lane line is detected, perform the autonomous stopping control of the vehicle so that the vehicle stops at a road shoulder included in the road.

8 . The non-transitory computer-readable medium according to claim 7 , wherein performing the autonomous stopping control comprises terminating the autonomous stopping control when a lane line is detected after starting the autonomous stopping control.

9 . A travel controller comprising a processor configured to:

autonomously control acceleration, deceleration, and steering of a vehicle; and

while the vehicle is traveling under autonomous control, perform a travel control processing comprising:

detecting whether a departure preventer, configured to prevent the vehicle from running off a road, is present on a road on which the vehicle is traveling based on data from a sensor mounted on the vehicle;

when no departure preventer is detected, determining a possibility of the vehicle reaching the road edge based on a comparison between an expected movement amount of the vehicle in a lateral direction until stopping from a current speed of the vehicle, and a lateral distance from the vehicle to the road edge,

when there is a possibility of the vehicle reaching the road edge, notifying a driver of a transition demand demanding transition from the autonomous control to a manual control of the vehicle, and when there is no possibility of the vehicle reaching the road edge, not notifying the driver of the transition demand; and

when a departure preventer is detected, terminating the travel control processing without determining the possibility of the vehicle reaching the road edge and without notifying the driver of the transition demand.

10 . The travel controller according to claim 9 , wherein the processor is further configured to:

calculate the expected movement amount of the vehicle in the lateral direction until stopping based on a maximum amount of movement of the vehicle in the lateral direction expected when steering by a steering operation amount not more than a steering operation threshold and decelerating by a predetermined acceleration rate until stopping from the current speed of the vehicle.

11 . The travel controller according to claim 9 , wherein the processor is further configured to:

perform detection of whether there is a lane line, demarcating a lane included in the road, based on the data from the sensor, and

when there is a possibility of the vehicle reaching the road edge and no lane line is detected, perform the autonomous stopping control of the vehicle so that the vehicle stops at a road shoulder included in the road.

12 . The travel controller according to claim 11 , wherein performing the autonomous stopping control comprises terminating the autonomous stopping control when a lane line is detected after starting the autonomous stopping control.