Electronic parking brake system and control method thereof
Disclosed is an electronic parking brake system including a piston provided to press a pair of brake pads disposed on opposite sides of a brake disk rotating together with a wheel of a vehicle, a nut member provided to press the piston, a spindle member provided to move the nut member, an electric motor provided to rotate the spindle member, an H-bridge having a pair of high-side switching elements and a pair of low-side switching elements to rotate the electric motor in a forward or backward direction, and a controller electrically connected to the H-bridge, wherein the controller is configured to detect a back electromotive force of the electric motor in a motor lock inspection mode for inspecting a lock failure of the electric motor and determine the lock failure of the electric motor based on a change in the detected back electromotive force.
1. An electronic parking brake system comprising:
a piston provided to press a pair of brake pads disposed on opposite sides of a brake disk rotating together with a wheel of a vehicle;
a nut member provided to press the piston;
a spindle member provided to move the nut member;
an electric motor provided to rotate the spindle member;
an H-bridge having a pair of high-side switching elements and a pair of low-side switching elements to rotate the electric motor in a forward or backward direction; and
a controller electrically connected to the H-bridge,
wherein the controller is configured to detect a back electromotive force of the electric motor in a motor lock inspection mode for inspecting a lock failure of the electric motor and determine the lock failure of the electric motor based on a change in the detected back electromotive force.
2. The electronic parking brake system according to claim 1 , wherein
the controller is configured to selectively turn on any one of the pair of high-side switching elements and the pair of low-side switching elements of the H-bridge in the motor lock inspection mode so that a current circulates through the turned-on switching elements and the electric motor.
3. The electronic parking brake system according to claim 1 , wherein
the controller is configured to initiate the motor lock inspection mode after completing driving of the electric motor for parking operation or parking release.
4. The electronic parking brake system according to claim 1 , wherein
the controller is configured to determine as the lock failure of the electric motor when a slope of the detected back electromotive force is greater than a preset slope.
5. The electronic parking brake system according to claim 1 , wherein
the controller is configured to, after completing driving of the electric motor for parking operation or parking release, selectively turn on any one of the pair of high-side switching elements and the pair of low-side switching elements, and at the same time detect the back electromotive force of the electric motor, and determine the lock failure of the electric motor based on the change in the detected back electromotive force.
6. A control method of an electronic parking brake system which comprises a piston provided to press a pair of brake pads disposed on opposite sides of a brake disk rotating together with a wheel of a vehicle, a nut member provided to press the piston, a spindle member provided to move the nut member, an electric motor provided to rotate the spindle member, and an H-bridge having a pair of high-side switching elements and a pair of low-side switching elements to rotate the electric motor in a forward or backward direction, the control method comprising:
detecting a back electromotive force of the electric motor in a motor lock inspection mode for inspecting a lock failure of the electric motor; and
determining the lock failure of the electric motor based on a change in the detected back electromotive force.
7. The control method according to claim 6 , further comprising
selectively turning on any one of the pair of high-side switching elements and the pair of low-side switching elements of the H-bridge in the motor lock inspection mode so that a current circulates through the turned-on switching elements and the electric motor.
8. The control method according to claim 6 , wherein
the detecting of the back electromotive force of the electric motor comprises initiating the motor lock inspection mode after completing driving of the electric motor for parking operation or parking release.
9. The control method according to claim 6 , wherein
the determining of the lock failure of the electric motor comprises determining as the lock failure of the electric motor when a slope of the detected back electromotive force is greater than a preset slope.