Electric brake device

An electric brake device comprising:

• a brake rotor;
• a frictional material configured to come into contact with the brake rotor;
• an electric motor;
• a motion converter mechanism configured to convert a driving force of the motor into a motion of the frictional material in a direction towards or away from the brake rotor;
• and
• a brake controller unit, the brake controller unit including:
• a motor rotational angle estimator configured to estimate a rotational angle of the motor;
• a braking force estimator configured to estimate a braking force that is actually being generated;
• a braking force controller configured to control the braking force by controlling the motor in such a way to follow a given target braking force;
• a clearance estimator configured to, based on the estimated rotational angle, estimate a clearance, inclusive of negative values, between the frictional material and the brake rotor;
• and
• a clearance controller configured to compare the target braking force with a predetermined switch-determining braking force, to generate, if the target braking force is below the switch-determining braking force, a target clearance, the target clearance being a clearance between the frictional material and the brake rotor which approaches zero or a predetermined negative value as the target braking force increases, and to use the estimated clearance to control the motor to follow the target clearance, in place of control performed by the braking force controller according to the target braking force.