Electromechanical brake device and method of controlling the same

A method of estimating a motor torque constant of an electromechanical brake device, which includes:

• a piston which moves forward in an axial direction so as to press a friction pad for clamping a disc at a time of performing a braking operation and moves backward in the axial direction at a time of releasing the braking operation;
• and an actuator which includes a motor that provides rotational force for moving the piston, the method comprising:
• providing a reaction force generating mechanism which generates reaction force applied against straight moving force of the piston and applies the reaction force to the piston when the piston moves backward in the axial direction, the reaction force being applied in a direction in which the braking operation is released;
• rotating the motor in a reverse direction, by a controller, in which the braking operation is released so as to allow the piston to move backward in the axial direction;
• detecting motor operating state information by using a sensor while the operation of the motor is controlled so that the piston moves backward in the axial direction;
• and
• estimating, by the controller, a motor torque constant that represents a correlation between motor electric current and motor rotational torque, based on the detected motor operating state information.

A method of controlling an electromechanical brake device, which includes:

• a piston which moves forward in an axial direction so as to press a friction pad for clamping a disc at a time of performing a braking operation and moves backward in the axial direction at a time of releasing the braking operation;
• an actuator which includes a motor that provides rotational force for moving the piston;
• and a reaction force generating mechanism which generates reaction force applied against straight moving force of the piston and applies the reaction force to the piston when the piston moves backward in the axial direction, the reaction force being applied in a direction in which the braking operation is released, the method comprising:
• rotating the motor in a reverse direction, by a controller, in which the braking operation is released so as to allow the piston to move backward in the axial direction;
• detecting motor operating state information by using a sensor while the operation of the motor is controlled so that the piston moves backward in the axial direction;
• estimating, by the controller, a motor torque constant which represents a correlation between motor electric current and motor rotational torque, based on the detected motor operating state information;
• and
• controlling, by the controller, electric current applied to the motor so as to generate desired motor rotational torque by using the estimated motor torque constant.