Electric brake system and method for controlling the same

1. An electric brake system for a vehicle comprising:

a calculator configured to calculate a target brake pressure based on a pedal effort sensed by a pedal sensor of the vehicle;

a first hydraulic circuit configured to form a brake pressure of at least one rear wheel;

a second hydraulic circuit configured to form a brake pressure of at least one front wheel; and

a controller configured to perform cooperative control during deceleration of a vehicle,

wherein the controller is configured to:

control the second hydraulic circuit to form the brake pressure of a front-wheel hydraulic pressure when a rear-wheel regenerative braking torque reaches a maximum regenerative braking torque; and

in response to the rear-wheel regenerative braking torque being reduced, increase the front-wheel hydraulic pressure to the target brake pressure and then increase a rear-wheel hydraulic pressure after increasing the front-wheel hydraulic pressure.

2. The electric brake system according to claim 1 , wherein the controller is configured to, when performing the cooperative control of the front-wheel hydraulic pressure, increase the front-wheel hydraulic pressure to a first threshold value.

3. The electric brake system according to claim 1 , wherein:

the controller is configured to, when performing the cooperative control, increase the front-wheel hydraulic pressure so as to form the amount of a braking torque corresponding to a difference between a braking torque based on driver's deceleration intention and a maximum regenerative braking torque.

4. The electric brake system according to claim 1 , wherein the controller is configured to increase the front-wheel hydraulic pressure to the target brake pressure, and then increase the rear-wheel hydraulic pressure to the target brake pressure after increasing the front-wheel hydraulic pressure to the target brake pressure.

5. The electric brake system according to claim 1 , wherein the controller is configured to perform deceleration of the vehicle by controlling only the front-wheel hydraulic pressure when variation of a sensed driver's braking pressure is higher than a second threshold value.

6. The electric brake system according to claim 5 , wherein the controller is configured to perform the rear-wheel regenerative braking when the front-wheel hydraulic pressure reaches a third threshold value.

7. The electric brake system according to claim 6 , wherein:

the controller is configured to, when the rear-wheel regenerative braking pressure reaches the maximum regenerative braking pressure, increase the front-wheel hydraulic pressure in a manner that a sum of a front-wheel torque and a maximum regenerative brake torque is identical to the target brake torque.

8. The electric brake system according to claim 5 , wherein:

the controller is configured to, when the front-wheel hydraulic pressure exceed a fourth threshold value, increase the rear-wheel hydraulic pressure to the target brake pressure, and reduce the front-wheel hydraulic pressure to the target brake pressure.

9. The electric brake system according to claim 8 , wherein the controller is configured to allow a consumption time needed to increase the rear-wheel hydraulic pressure to the target brake pressure to be identical to another consumption time needed to reduce the front-wheel hydraulic pressure to the target brake pressure when the controller increases the rear-wheel hydraulic pressure to the target brake pressure and reduces the front-wheel hydraulic pressure to the target brake pressure.

10. The electric brake system according to claim 8 , wherein the controller is configured to, when the front-wheel hydraulic pressure exceeds the fourth threshold value, not to perform the rear-wheel regenerative braking.

11. The electric brake system according to claim 9 , wherein the controller is configured to, when the front-wheel hydraulic pressure exceeds the third threshold value after the rear-wheel regenerative braking is released, not to perform the rear-wheel regenerative braking.

12. A method for controlling an electric brake system of a vehicle, the method comprising:

calculating a target brake pressure based on a pedal effort sensed by a pedal sensor of the vehicle;

controlling either a first hydraulic circuit that forms a brake pressure of at least one rear wheel or a second hydraulic circuit that forms a brake pressure of at least one front wheel; and

performing cooperative control during deceleration of the vehicle,

wherein the performing of the cooperative control comprises:

controlling the second hydraulic circuit to form the brake pressure of a front-wheel hydraulic pressure when the rear-wheel regenerative braking torque reaches a maximum regenerative braking torque; and

in response to the rear-wheel regenerative braking torque being reduced, increasing the front-wheel hydraulic pressure to the target brake pressure and then increasing a rear-wheel hydraulic pressure after increasing the front-wheel hydraulic pressure.

13. The method according to claim 12 , wherein the increasing the rear-wheel hydraulic pressure includes:

synchronizing the front-wheel hydraulic pressure and the rear-wheel hydraulic pressure by increasing the rear-wheel hydraulic pressure to the target brake pressure.