Vehicle system and vehicle

1. A vehicle system comprising:

a warning device including at least one of a vibration generation device configured to generate vibration and a sound output device configured to output sound, and

an electronic control unit configured to

prompt an operator of a vehicle to pay attention ahead when a change in a traffic environment is detected while the vehicle is performing autonomous driving;

determine whether the operator is facing forward;

determine whether the operator holds a steering wheel;

cause the warning device to perform a first warning when it is determined that the operator is not facing forward;

cause the warning device to perform a second warning which is stronger than the first warning when it is determined that the operator is not holding the steering wheel; and

cause the warning device to terminate the second warning when it is determined that the operator is holding the steering wheel,

wherein the electronic control unit increments a number of re-holding times of the steering wheel and performs a notification to notify that the autonomous driving will be terminated based on the number of re-holding times.

2. The vehicle system according to claim 1 , wherein

the electronic control unit is configured to:

increment the number of re-holding times, when it is determined that the operator faces forward before a second predetermined time elapses after the second warning is started or when it is determined that the operator holds the steering wheel before the second predetermined time elapses after the second warning is started; and

output a signal for terminating the autonomous driving of the vehicle to an autonomous driving electronic control unit, when the number of re-holding times while a light stimulus is being presented, is equal to or greater than a threshold, the autonomous driving electronic control unit being provided in the vehicle and being configured to perform the autonomous driving of the vehicle,

wherein the light stimulus is presented by a head-up display, when the change in the traffic environment is detected ahead of the vehicle while the vehicle is performing autonomous driving.

3. The vehicle system according to claim 2 , wherein

the electronic control unit is configured to decelerate the vehicle or stop the vehicle when it is determined that the operator does not hold the steering wheel before the second predetermined time elapses after the second warning is started.

4. The vehicle system according to claim 1 , wherein

the electronic control unit is configured to decelerate the vehicle or to stop the vehicle when it is determined that the operator does not hold the steering wheel before a second predetermined time elapses after the second warning is started.

5. The vehicle system according to claim 1 , further comprising

a driver monitor camera,

wherein the electronic control unit is configured to detect whether the operator is facing forward by using the driver monitor camera.

6. The vehicle system according to claim 1 , wherein

the second warning has a stimulus intensity higher than the stimulus intensity of the first warning.

7. The vehicle system according to claim 1 , wherein

the second warning is performed to stimulate a number of senses of the driver greater than a number of senses that the first warning is performed to stimulate.

8. The vehicle system according to claim 1 , wherein

the vibration generation device includes a weight and a motor configured to rotate the weight to generate the vibration, and the sound output device includes a speaker configured to output the sound.

9. The vehicle system according to claim 1 , further comprising

an autonomous driving electronic control unit configured to perform the autonomous driving of the vehicle, wherein

the electronic control unit is configured to

cause the autonomous driving electronic control unit to perform the autonomous driving of the vehicle;

increment the number of re-holding times when it is determined that the operator faces forward before a second predetermined time elapses after the second warning is started or when it is determined that the operator holds the steering wheel before the second predetermined time elapses after the second warning is started; and

output a signal for terminating the autonomous driving of the vehicle to the autonomous driving electronic control unit when the number of re-holding times is equal to or greater than a threshold.

10. The vehicle system according to claim 9 , wherein

the electronic control unit is configured to decelerate the vehicle or to stop the vehicle when it is determined that the operator does not hold the steering wheel before the second predetermined time elapses after the second warning is started.

11. A method comprising:

prompting an operator of a vehicle to pay attention ahead when a change in a traffic environment is detected while the vehicle is performing autonomous driving;

determining whether the operator is facing forward;

determining whether the operator holds a steering wheel;

causing a warning device to perform a first warning when it is determined that the operator is not facing forward;

causing the warning device to perform a second warning which is stronger than the first warning when it is determined that the operator is not holding the steering wheel;

causing the warning device to terminate the second warning when it is determined that the operator is holding the steering wheel; and

incrementing a number of re-holding times of the steering wheel and performing a notification to notify that the autonomous driving will be terminated based on the number of re-holding times,

wherein the warning device includes at least one of a vibration generation device configured to generate vibration and a sound output device configured to output sound.

12. The method according to claim 11 , wherein

incrementing the number of re-holding times comprises incrementing the number of re-holding times when it is determined that the operator faces forward before a second predetermined time elapses after the second warning is started or when it is determined that the operator holds the steering wheel before the second predetermined time elapses after the second warning is started, and

the method further comprises outputting a signal for terminating the autonomous driving of the vehicle to an autonomous driving electronic control unit, when the number of re-holding times while a light stimulus is being presented, is equal to or greater than a threshold, the autonomous driving electronic control unit being provided in the vehicle and being configured to perform the autonomous driving of the vehicle,

wherein the light stimulus is presented by a head-up display, when the change in the traffic environment is detected ahead of the vehicle while the vehicle is performing autonomous driving.

13. The method according to claim 12 , further comprising

decelerating the vehicle or stopping the vehicle when it is determined that the operator does not hold the steering wheel before the second predetermined time elapses after the second warning is started.

14. The method according to claim 11 , further comprising

decelerating the vehicle or stopping the vehicle when it is determined that the operator does not hold the steering wheel before a second predetermined time elapses after the second warning is started.

15. The method according to claim 11 , further comprising

detecting whether the operator is facing forward by using a driver monitor camera.

16. The method according to claim 11 , wherein

the second warning has a stimulus intensity higher than the stimulus intensity of the first warning.

17. The method according to claim 11 , further comprising

causing an autonomous driving electronic control unit to perform the autonomous driving of the vehicle, the autonomous driving electronic control unit being provided in the vehicle and being configured to perform the autonomous driving of the vehicle; and

outputting a signal for terminating the autonomous driving of the vehicle to the autonomous driving electronic control unit when the number of re-holding times is equal to or greater than a threshold, wherein

incrementing the number of re-holding times comprises incrementing the number of re-holding times when it is determined that the operator faces forward before a second predetermined time elapses after the second warning is started or when it is determined that the operator holds the steering wheel before the second predetermined time elapses after the second warning is started.

18. The method according to claim 17 , further comprising

decelerating the vehicle or stopping the vehicle when it is determined that the operator does not hold the steering wheel before the second predetermined time elapses after the second warning is started.

19. The method according to claim 11 , wherein

the second warning is performed to stimulate a number of senses of the driver greater than a number of senses that the first warning is performed to stimulate.

20. The method according to claim 11 , wherein

the vibration generation device includes a weight and a motor configured to rotate the weight to generate the vibration, and the sound output device includes a speaker configured to output the sound.