Vehicle control system and vehicle control method

1. A vehicle control system that controls a vehicle of a steer-by-wire type,

the vehicle control system comprising one or more processors configured to execute:

driving assist control that assists driving of the vehicle; and

conjunction reaction force control that applies a steering reaction force component to a steering wheel in conjunction with turning of the vehicle caused by the driving assist control, wherein

a system turn angle is a target turn angle of the driving assist control,

a driving assist direction is a direction of the turning of the vehicle caused by the driving assist control, and

the conjunction reaction force control includes feedforward reaction force control that moves the steering wheel in a same direction as the driving assist direction without depending on a steering angle of the steering wheel and a magnitude of the system turn angle.

2. The vehicle control system according to claim 1 , wherein

the feedforward reaction force control includes:

a driving assist direction acquisition process that acquires information on the driving assist direction; and

applying a steering reaction force component that moves the steering wheel in the same direction as the driving assist direction to the steering wheel.

3. The vehicle control system according to claim 2 , wherein

the driving assist direction acquisition process includes:

acquiring the system turn angle; and

determining the driving assist direction based on the system turn angle.

4. The vehicle control system according to claim 3 , wherein

the driving assist direction acquisition process further includes:

calculating a system turn angular velocity by differentiating the system turn angle; and

determining the driving assist direction based on the system turn angular velocity.

5. The vehicle control system according to claim 1 , wherein

the steering reaction force component caused by the feedforward reaction force control is set to a value greater than a static frictional force acting on a steering shaft coupled with the steering wheel.

6. The vehicle control system according to claim 1 , wherein

the conjunction reaction force control further includes feedback reaction force control,

the feedback reaction force control includes:

acquiring a driver turn angle that is a target turn angle corresponding to the steering angle of the steering wheel;

acquiring the system turn angle; and

applying a steering reaction force component to the steering wheel in a direction of reducing a difference between the driver turn angle and the system turn angle.

7. A vehicle control method that controls a vehicle of a steer-by-wire type,

the vehicle control method comprising:

driving assist control that assists driving of the vehicle; and

conjunction reaction force control that applies a steering reaction force component to a steering wheel in conjunction with turning of the vehicle caused by the driving assist control, wherein

a system turn angle is a target turn angle of the driving assist control,

a driving assist direction is a direction of the turning of the vehicle caused by the driving assist control, and

the conjunction reaction force control includes feedforward reaction force control that moves the steering wheel in a same direction as the driving assist direction without depending on a steering angle of the steering wheel and a magnitude of the system turn angle.

8. The vehicle control system according to claim 1 , wherein the driving assist direction is a first value or a second value, and

wherein the first value corresponds to a left direction, and the second value corresponds to a right direction.

9. The vehicle control method according to claim 7 , wherein the driving assist direction is a first value or a second value,

wherein the first value corresponds to a left direction, and the second value corresponds to a right direction.