Electric power steering device

An electric power steering device for applying steering assist force to a steering mechanism of a vehicle though a reducer by driving an electric motor in response to an operating amount applied by an operating member for vehicle steering, the electric power steering device comprising:

• a steering angular-speed detector for detecting steering angular speed corresponding to rate of steering-angle variation caused by the operation of the operating member;
• a rotational speed detector for detecting rotational speed corresponding to rate of rotational angle variation of the electric motor;
• a target value setting unit for setting a current target value to be supplied to the electric motor;
• a current detector for detecting current flowing in the electric motor and outputting the detected current value;
• a controller for generating an instruction value for feed-back control to the driving of the electric motor on the basis of current deviation between the current target value and the current detection value;
• and
• a driving unit for driving the electric motor in accordance with the instruction value,
• wherein the target value setting unit includes,
• a deviation calculator for calculating angular speed deviation based on the rotational speed, reduction ratio of the reducer and the steering angular speed, and
• a target value calculator for calculating the target value of current by multiplying integration value corresponding to the operating amount, obtained by integrating the angular speed deviation, by a predetermined integration gain.