Control device for vehicle and control method for vehicle

1. A control device for vehicle that generates a friction braking force, via friction brakes, to decelerate a vehicle, the control device for vehicle comprising:

a vehicle speed sensor configured to detect a speed parameter proportionate to a traveling speed of the vehicle;

an accelerator position sensor configured to detect an accelerator operation amount; and

a controller configured to control the friction brakes; and

wherein the controller is further configured to:

estimate a disturbance torque acting on the vehicle based on disturbance factors;

electrically adjust a friction braking amount; and

control the friction braking amount to converge to a value decided on a basis of the disturbance torque in conjunction with a reduction in the speed parameter when the accelerator operation amount is equal to or less than a predetermined value and the vehicle is just before a stop of the vehicle.

2. The control device for vehicle according to claim 1 , wherein the controller is further configured to:

multiply the speed parameter by a predetermined gain to calculate a speed feedback torque,

wherein the controller is further configured to decide the friction braking amount on a basis of the speed feedback torque and the disturbance torque.

3. The control device for vehicle according to claim 1 , wherein

the controller is further configured to estimate the disturbance torque on a basis of a model for a transfer characteristic of the speed parameter with respect to a torque input to the vehicle and the friction braking amount.

4. The control device for vehicle according to claim 3 , wherein the controller is further configured to:

detect a friction-braking-amount-related value related to the friction braking amount,

wherein the friction braking amount is used by the controller to estimate the disturbance torque, the friction braking amount being calculated on a basis of the friction-braking-amount-related value detected by the controller.

5. The control device for vehicle according to claim 3 , wherein the friction braking amount used by the controller to estimate the disturbance torque is a friction-braking-amount command value.

6. The control device for vehicle according to claim 3 , wherein the controller is configured to estimate the disturbance torque on a basis of a model for a transfer characteristic of the speed parameter with respect to the torque input to the vehicle, a model for a transfer characteristic of the speed parameter with respect to an input of the friction braking amount to the vehicle, and the friction braking amount.

7. The control device for vehicle according to claim 1 , wherein the controller is further configured to:

calculate a first torque target value on a basis of vehicle information;

calculate a second torque target value, the second torque target value converging to the disturbance torque in conjunction with the reduction in the speed parameter; and

compare a magnitude of the first torque target value with a magnitude of the second torque target value to determine whether the vehicle is just before the stop of the vehicle, wherein the controller is configured to decide the friction braking amount on a basis of the first torque target value when the vehicle is determined as not being just before the stop of the vehicle, and the controller is configured to decide the friction braking amount on a basis of the second torque target value when the vehicle is determined as being just before the stop of the vehicle.

8. The control device for vehicle according to claim 1 , wherein the speed parameter is a rotation speed of an electric motor.

9. The control device for vehicle according to claim 8 , wherein the controller is further configured to cause a torque from the electric motor to converge to the disturbance torque in conjunction with a reduction in the rotation speed of the electric motor when the accelerator operation amount is equal to or less than a predetermined value and the vehicle is just before the stop of the vehicle on an uphill road.

10. A control method for vehicle that generates a friction braking force, via friction brakes, to decelerate a vehicle, the control method for vehicle comprising:

detecting a speed parameter proportionate to a traveling speed of the vehicle;

detecting an accelerator operation amount;

estimating, via a controller, a disturbance torque acting on the vehicle based on disturbance factors; and

controlling, via the controller, a friction braking amount, to control the friction brakes, to converge to the disturbance torque in conjunction with a reduction in the speed parameter when the accelerator operation amount is equal to or less than a predetermined value and the vehicle is just before a stop of the vehicle.