Electronic parking brake system and control method thereof

1 . An electronic parking brake system, comprising:

an electronic parking brake that includes an electronic parking brake actuator applied by a motor;

a current sensor configured to detect a current flowing in the motor;

a processor configured to control a parking apply operation of the electronic parking brake; and

a memory configured to store an inrush current generated during the parking apply operation of the electronic parking brake in a no-load condition,

wherein the processor is configured to:

in the no-load condition, store the inrush current generated during the parking apply operation of the electronic parking brake a preset number of times;

store the inrush current generated when the parking of the electronic parking brake is released the preset number of times;

calculate an average value of the stored inrush current;

calculate an inrush current model based on the average value of the inrush current; and

identify a clamping force of the electronic parking brake actuator based on the inrush current model and the inrush current.

2 . The electronic parking brake system according to claim 1 , wherein the inrush current model is an Nth order function,

wherein the processor is configured to store coefficients of the Nth order function in the memory, and

wherein N is a natural number.

3 . The electronic parking brake system according to claim 2 , wherein the processor is configured to estimate a driving current of the motor by removing from the Nth order function the inrush current generated during the parking apply operation or parking release operation of the electronic parking brake.

4 . The electronic parking brake system according to claim 3 , wherein the processor is configured to identify a clamping force of the electronic parking brake actuator based on the estimated driving current.

5 . The electronic parking brake system according to claim 1 , wherein the inrush current model includes a first inrush current model and a second inrush current model, and

the processor is configured to calculate the first inrush current model based on an average value of the first inrush current, and calculate the second inrush current model based on an average value of the second inrush current.

6 . The electronic parking brake system according to claim 5 , wherein the first inrush current model and the second inrush current model are an Nth order function,

wherein the processor is configured to store each coefficient of each Nth order function in the memory, and

wherein N is a natural number.

7 . A control method of an electronic parking brake system including an electronic parking brake actuator applied by a motor, the control method comprising:

identifying a no-load condition;

in the no-load condition, storing an inrush current generated during a parking apply operation of an electronic parking brake a preset number of times;

storing the inrush current generated when the parking of the electronic parking brake is released the preset number of times;

calculating an average value of the stored inrush current;

calculating an inrush current model based on the average value of the inrush current; and

identifying a clamping force of the electronic parking brake actuator based on the inrush current model and the inrush current.

8 . The control method according to claim 7 , wherein the inrush current model is an Nth order function,

wherein the calculating of the inrush current model includes storing coefficients of the Nth order function, and

wherein N is a natural number.

9 . The control method according to claim 8 , further comprising:

estimating a driving current of the motor by removing from the Nth order function the inrush current generated during the parking apply operation or parking release operation of the electronic parking brake, and

identifying a clamping force of the electronic parking brake actuator based on the estimated driving current.

10 . The control method according to claim 7 , wherein:

the inrush current model includes a first inrush current model and a second inrush current model, and

the calculating of the inrush current model includes:

calculating the first inrush current model based on an average value of the first inrush current, and

calculating the second inrush current model based on an average value of the second inrush current.

11 . The control method according to claim 10 , wherein the first inrush current model and the second inrush current model are an Nth order function,

wherein the calculating of the inrush current model includes storing each coefficient of the Nth order function, and

wherein N is a natural number.

12 . A control method of an electronic parking brake system including an electronic parking brake actuator applied by a motor, the control method comprising:

identifying a no-load condition;

in the no-load condition, storing an inrush current generated during a parking apply operation of an electronic parking brake a preset number of times;

storing the inrush current generated when the parking of the electronic parking brake is released the preset number of times;

calculating an average value of the stored inrush current;

calculating an inrush current model based on the average value of the inrush current; and

identifying a clamping force of the electronic parking brake actuator during the parking apply operation of the electronic parking brake in the no-load condition based on the inrush current model and the inrush current.