Electric brake system and method thereof

1. An electronic brake system including a motor configured to drive a pump for pumping brake oil from a reservoir of a master cylinder, an accumulator configured to store the pumped brake oil according to operation of the pump driven by the motor, a first hydraulic circuit configured to control a hydraulic pressure generated by the accumulator to be transmitted to at least one first wheel, and a second hydraulic circuit configured to control the hydraulic pressure generated by the accumulator to be transmitted to at least one second wheel, the electronic brake system comprising:

a pressure sensor including a first pressure sensor configured to measure a hydraulic pressure of the accumulator, a second pressure sensor configured to measure a hydraulic pressure of the first hydraulic circuit, and a third pressure sensor configured to measure a hydraulic pressure of the second hydraulic circuit;

a driver including one or more apply valves and release valves configured to control the hydraulic pressures of the first hydraulic circuit and the second hydraulic circuit;

a determiner configured to determine that at least one of the first hydraulic circuit and the second hydraulic circuit has failed when an absolute value of a slope of the pressure measured by the first pressure sensor is greater than a preset first threshold value and the pressure measured by the first pressure sensor is less than a preset second threshold value; and

a controller configured to close apply valves of the first hydraulic circuit and the second hydraulic circuit when the failure has been determined, determine that a leak has occurred in one of the first and second hydraulic circuits having an amount of pressure change greater than that of the other hydraulic circuit measured on the basis of the second pressure sensor and the third pressure sensor, and control braking using only the hydraulic circuit operating normally.

2. The electronic brake system of claim 1 , wherein the determiner further determines that at least one of the first hydraulic circuit and the second hydraulic circuit has failed when the absolute value of the slope of the pressure measured by the first pressure sensor is greater than the preset first threshold value, and at least one of the pressures measured by the second pressure sensor and the third pressure sensor is less than a preset third threshold value.

3. The electronic brake system of claim 2 , wherein the determination that the leak has occurred in one of the first and second hydraulic circuits having the amount of pressure change greater than that of the other hydraulic circuit measured on the basis of the second pressure sensor and the third pressure sensor after the apply valves of the first hydraulic circuit and the second hydraulic circuit are closed determines that the leak has occurred in one of the first and second hydraulic circuits having an amount of pressure change greater than that of the other hydraulic circuit when a difference between the amount of pressure change measured by the second pressure sensor and the amount of pressure change measured by the third pressure sensor is greater than the preset third threshold value.

4. The electronic brake system of claim 3 , wherein the determination that the leak has occurred in one of the first and second hydraulic circuits having the amount of pressure change greater than that of the other hydraulic circuit measured on the basis of the second pressure sensor and the third pressure sensor after the apply valves of the first hydraulic circuit and the second hydraulic circuit are closed is determined within a preset time.

5. The electronic brake system of claim 4 , wherein:

the amount of pressure change measured by the second pressure sensor denotes a difference between a pressure measured at a time at which the apply valve included in the first hydraulic circuit is closed and a pressure measured after a preset first time from a time at which the apply valve is opened; and

the amount of pressure change measured by the third pressure sensor denotes a difference between a pressure measured at a time at which the apply valve included in the second hydraulic circuit is closed and a pressure measured after the preset first time from a time at which the apply valve is closed.

6. The electronic brake system of claim 5 , wherein the controller forms the hydraulic circuit that has been determined to have the leak into a closed circuit.

7. A control method of an electronic brake system including a motor configured to drive a pump for pumping brake oil from a reservoir of a master cylinder, an accumulator configured to store the pumped brake oil according to operation of the pump driven by the motor, a first hydraulic circuit configured to control a hydraulic pressure generated by the accumulator to be transmitted to at least one first wheel, and a second hydraulic circuit configured to control the hydraulic pressure generated by the accumulator to be transmitted to at least one second wheel, the control method comprising:

measuring a hydraulic pressure of the accumulator, a hydraulic pressure of the first hydraulic circuit, and a hydraulic pressure of the second hydraulic circuit;

driving valves included in the first hydraulic circuit and the second hydraulic circuit on the basis of the measured hydraulic pressure of the accumulator, the measured hydraulic pressure of the first hydraulic circuit, and the measured hydraulic pressure of the second hydraulic circuit;

determining that at least one of the first hydraulic circuit and the second hydraulic circuit has failed when a magnitude of a slope of the measured hydraulic pressure of the accumulator is greater than a preset first threshold value and the measured hydraulic pressure of the accumulator is less than a preset second threshold value;

closing apply valves included in the first hydraulic circuit and the second hydraulic circuit when the failure is determined;

determining that a leak has occurred in one of the first and second hydraulic circuits having an amount of hydraulic pressure change greater than that of the other hydraulic circuit measured on the basis of the hydraulic pressures of the first hydraulic circuit and the second hydraulic circuit measured after the apply valves are closed; and

determining that one of the first and second hydraulic circuits having an amount of hydraulic pressure change less than that of the other hydraulic circuit measured on the basis of the hydraulic pressures of the first hydraulic circuit and the second hydraulic circuit measured after the apply valves are closed operates normally, and controlling braking of only the hydraulic circuit operating normally.

8. The control method of claim 7 , wherein the determining that the leak has occurred in one of the first and second hydraulic circuits having the amount of pressure change greater than that of the other hydraulic circuit measured on the basis of the second pressure sensor and the third pressure sensor after the apply valves of the first hydraulic circuit and the second hydraulic circuit is performed within a preset time.

9. The control method of claim 7 , further comprising determining that at least one of the first hydraulic circuit and the second hydraulic circuit has failed when the magnitude of the slope of the hydraulic pressure of the accumulator is greater than the preset first threshold value and at least one of the hydraulic pressures of the first hydraulic circuit and the second hydraulic circuit is less than a preset third threshold value.

10. The control method of claim 9 , wherein the determining that the leak has occurred in one of the first and second hydraulic circuits having the amount of hydraulic pressure change greater than that of the other hydraulic circuit measured on the basis of the hydraulic pressures of the first hydraulic circuit and the second hydraulic circuit after the apply valves are opened determines that the leak has occurred in one of the first and second hydraulic circuits having an amount of hydraulic pressure change greater than that of the other hydraulic circuit when a difference between the amount of hydraulic pressure change of the first hydraulic circuit and the amount of hydraulic pressure change of the second hydraulic circuit is greater than the preset third threshold value.

11. The control method of claim 10 , wherein the amount of hydraulic pressure change denotes a difference between an amount of hydraulic pressure change measured at a time at which the apply valves are closed and an amount of hydraulic pressure change measured after a preset first time passes from a time at which the apply valves are opened.

12. The control method of claim 11 , further comprising forming the one of the first and second hydraulic circuits that has been determined to have the leak into a closed circuit.