Electro-mechanical brake and control method therefor

A control method for an electro-mechanical brake in a vehicle, the electro-mechanical brake including a piston driven by a motor and configured to push a brake pad toward a wheel disc, the control method comprising:

• generating a first map in a first state, wherein the first state is a state of the electro-mechanical brake when power is applied to the vehicle at start-up, the state of the electro-mechanical brake changes from the first state when a temperature and volume of the brake pad changes or the brake pad wears, and the first map comprises data correlating current flowing through the motor, a position of the piston, and a braking force relative to the first state;
• generating a second map when in the first state wherein the second map comprises data correlating current flowing through the motor and a factor, where the factor is a ratio of the braking force to the current flowing through the motor;
• detecting a position of the piston when braking is performed;
• detecting a current value flowing through the motor when braking is performed;
• and
• detecting a braking force value based on the piston position, the current value, the first map, and the second map.

An electro-mechanical brake including a piston configured to be driven by a motor to push a brake pad toward a wheel disc of a vehicle, the electro-mechanical brake comprising:

• a current detection unit configured to detect a current flowing through the motor;
• a position detection unit configured to detect a position of the piston;
• a map generating unit configured to generate a first map and a second map in a first state, wherein
• the first state is a state of the electro-mechanical brake when power is applied to the vehicle at start-up,
• the first map comprises data correlating current flowing through the motor, position of the piston, and braking force with reference to the first state,
• the second map comprises data of current flowing through the motor and a factor with reference to the first state, and
• the factor is a ratio of braking force to current flowing through the motor;
• and
• a braking force value detection unit configured to detect a braking force value based on a piston position detected by the position detection unit, a current value detected by the current detection unit, the first map, and the second map when braking is performed,
• wherein the braking force value detection unit includes
• a first braking force value determination unit configured to determine a value of braking force output when the piston position is input to the first map, as a first braking force value;
• a difference value detection unit configured to detect a difference value between the current value and a value of a current that is output when the piston position is input to the first map;
• and
• a compensation value determination unit configured to multiply the difference value by a first factor value to determine a compensation value, wherein the first factor value is output when the current value is input to the second map;
• and
• wherein
• a decision is made that stiffness of the brake pad has increased when the difference value is greater than 0, and
• a decision is made that the stiffness of the brake pad has decreased when the difference value is smaller than 0.