Apparatus and method for controlling braking pressure of powered booster brake system

1. An apparatus for controlling a braking pressure of a powered booster brake system, comprising:

a pedal stroke sensor configured to detect a manipulation degree of a brake pedal;

an electronic control unit configured to calculate the braking pressure of the powered booster brake system using the detection result of the pedal stroke sensor; and

a motor configured to move a piston inside a pump to perform a braking operation under control of the ECU,

wherein the ECU determines a first position of the piston based on the calculated braking pressure of the powered booster brake system, and controls the motor to move the piston to the first position of the piston determined based on the calculated braking pressure of the powered booster brake system,

wherein the apparatus further comprises a pressure sensor configured to detect a fluid pressure in the pump, which is used in the braking operation, in a state in which the piston is moved to the first position, and provide the fluid pressure to the ECU, and

wherein the ECU compares the fluid pressure detected by the pressure sensor with the braking pressure, determines a second position of the piston, which is capable of compensating for a difference between the fluid pressure and the braking pressure when the difference occurs therebetween, and drives the motor to move the piston to the second position.

2. The apparatus of claim 1 , wherein, when the difference between the fluid pressure and the braking pressure falls within an error range, the ECU determines the first position as a normal position and stops movement control of the piston.

3. The apparatus of claim 1 , wherein the ECU determines the first position or the second position using a lookup table in which position information of the piston according to braking pressure is stored.

4. The apparatus of claim 3 , wherein the position information of the piston stored in the lookup table is changed according to a required fluid amount which is necessary to form a braking force of a vehicle.

5. The apparatus of claim 1 , wherein the ECU repeats movement control of the piston to compensate for the difference between the fluid pressure, which is detected by the pressure sensor, and the braking pressure.

6. A method for controlling a braking pressure of a powered booster brake system, comprising:

detecting a manipulation degree of a brake pedal;

calculating the braking pressure of the powered booster brake system using the manipulation degree of the brake pedal;

determining a first position of the piston based on the calculated brake pressure of the powered booster brake system;

driving a motor to move the piston to the first position of the piston determined based on the calculated braking pressure of the powered booster brake system; and

detecting a fluid pressure used in the braking operation in a state in which the piston is moved to the first position, and comparing the fluid pressure with the braking pressure, determining a second position for compensating for a difference when the difference occurs between the fluid pressure and the braking pressure, and moving the piston to the second position.

7. The method of claim 6 , wherein the first position or the second position is determined using a lookup table in which position information of the piston according to braking pressure is stored.

8. The method of claim 6 , wherein movement control of the piston is repeatedly performed to compensate for the difference between the detected fluid pressure and the braking pressure.

9. The apparatus of claim 1 , wherein the ECU determines the first position of the piston using a lookup table storing associations between positions of the piston and braking pressures.

10. The method of claim 6 , wherein the first position of the piston is determined using a lookup table storing associations between positions of the piston and braking pressures.

11. The apparatus of claim 1 , wherein the ECU controls the motor using a lookup table storing positions of the piston and movement speeds of the piston with respect to braking pressures.

12. The method of claim 6 , wherein the driving the motor further comprises driving the motor using a lookup table storing positions of the piston and movement speeds of the piston with respect to braking pressures.

13. The apparatus of claim 1 , wherein the pedal stroke sensor is configured to detect the manipulation degree of the brake pedal including a depression degree and a depression speed of the brake pedal.

14. The method of claim 6 , wherein the manipulation degree of the brake pedal includes a depression degree and a depression speed of the brake pedal.