Electronic parking brake system and control method thereof

1. An electronic parking brake system that generates a clamping force required for parking of trailer-mounted towing vehicles, the electronic parking brake system comprising:

an electronic parking brake provided on at least one of front and rear wheels of the towing vehicle; and

a controller configured to

receive a front wheel speed, a rear wheel speed, and a longitudinal acceleration of the towing vehicle,

determine whether or not the trailer is mounted based on changes in the received front wheel speed, rear wheel speed, and longitudinal acceleration when the towing vehicle passes a speed bump,

determine the clamping force required for parking according to whether or not the trailer is mounted when parking is operated, and

control the electronic parking brake to generate the determined clamping force,

wherein the controller is configured to

check a first condition in which a front wheel disturbance or a rear wheel disturbance occurs within a first preset time after both the front and rear wheels of the towing vehicle pass through the speed bump, the first preset time being measured from a time when an initial rear wheel disturbance occurs and from a first driving speed of the towing vehicle and a first distance between a rear wheel axle of the towing vehicle and a trailer wheel axle of the trailer, wherein the front wheel disturbance or the rear wheel disturbance is determined based on at least one of the received front wheel speed and the received rear wheel speed,

check a second condition in which a first vehicle shaking occurs in the towing vehicle within a second preset time after both the front and rear wheels of the towing vehicle pass through the speed bump, wherein the first vehicle shaking is determined based on the longitudinal acceleration when the towing vehicle passes the speed bump,

determine whether a third condition in which a second vehicle shaking occurs when the towing vehicle stops, is satisfied, when both the first trailer mounting condition and the second trailer mounting condition are satisfied, wherein the second vehicle shaking is determined based on a longitudinal acceleration according to operating an inertia brake of the trailer mounted on the towing when the towing vehicle stops, and

determine that the trailer is mounted on the towing in response to the first-third condition being satisfied.

2. The electronic parking brake system according to claim 1 , wherein the controller is configured to determine whether the front and rear wheels of the towing vehicle pass through the speed bump based on a time interval between a time when an initial front wheel disturbance occurs in the received front wheel speed and the time when the initial rear wheel disturbance occurs in the received rear wheel speed.

3. The electronic parking brake system according to claim 1 , wherein the second preset time is determined based on a second driving speed of the towing vehicle and a second distance between the rear wheel axle of the towing vehicle and the trailer wheel axle of the trailer.

4. The electronic parking brake system according to claim 3 , wherein the controller is configured to determine whether the front and rear wheels of the towing vehicle pass through the speed bump based on a time interval between a time when one shaking of the towing vehicle occurs and a time when an other shaking of the towing vehicle occurs.

5. The electronic parking brake system according to claim 4 , wherein the controller is configured to determine the second condition is satisfied in response to the first vehicle shaking occurring within the second preset time measured from a point of time where a shaking of the towing vehicle occurs when the rear wheel of the towing vehicle passes through the speed bump.

6. A control method of an electronic parking brake system that generates a clamping force required for parking of a trailer mounted towing vehicle, the control method comprising:

receiving a front wheel speed, a rear wheel speed and a longitudinal acceleration of the towing vehicle,

determining whether or not the trailer is mounted based on changes in the received front wheel speed, rear wheel speed, and longitudinal acceleration when the towing vehicle passes the speed bump,

determining the clamping force required for parking according to whether or not the trailer is installed when parking is operated, and

generating the determined clamping force by the electronic parking brake,

wherein the determining whether or not the trailer is mounted comprises:

checking a first condition in which a front wheel disturbance or a rear wheel disturbance occurs within a first preset time after both the front and rear wheels of the towing vehicle pass through the speed bump, the first preset time being measured from a time when an initial rear wheel disturbance occurs and determined based on a first driving speed of the towing vehicle and a first distance between a rear wheel axle of the towing vehicle and a trailer wheel axle of the trailer, wherein the front wheel disturbance or the rear wheel disturbance is determined based on at least one of the received front wheel speed and the received rear wheel speed,

checking a second condition in which first vehicle shaking occurs in the towing vehicle within a second preset time after both the front and rear wheels of the towing vehicle pass through the speed bump, wherein the first vehicle shaking is determined based on the longitudinal acceleration when the towing vehicle passes the speed bump,

determining whether a third condition in which second vehicle shaking occurs when the towing vehicle stops, is satisfied, when both the first trailer mounting condition and the second trailer mounting condition are satisfied, wherein the second vehicle shaking is determined based on a longitudinal acceleration according to operating an inertia brake of the trailer mounted on the towing when the towing vehicle stops, and

determining that the trailer is mounted on the towing in response to the third condition being satisfied.

7. The method according to claim 6 , wherein the determining whether or not the trailer is mounted comprises: determining whether the front and rear wheels of the towing vehicle pass through the speed bump based on a time interval between a time when an initial front wheel disturbance occurs in the received front wheel speed and the time when the initial rear wheel disturbance occurs in the received rear wheel speed.

8. The method according to claim 6 , wherein the second preset time is determined based on a second driving speed of the towing vehicle and a second distance between the rear wheel axle of the towing vehicle and the trailer wheel axle of the trailer.

9. The method according to claim 8 , wherein the determining whether or not the trailer is mounted comprises:

determining whether the front and rear wheels of the towing vehicle pass through the speed bump based on a time interval between a time when one shaking of the towing vehicle occurs and a time when an other shaking of the towing vehicle occurs.