Electric power steering apparatus

An electric power steering apparatus comprising:

• a steering torque sensor for detecting a steering torque of a steering system;
• a steering velocity sensor for detecting a steering velocity of said steering system;
• a steering torque differentiating section for producing a differential value of the steering torque;
• a motor control signal determining section including a target value setter which receives a signal value corresponding to the steering torque and which outputs a target value, said determining section for subtracting a value corresponding to the steering velocity from a value corresponding to the differential value of the steering torque to obtain a result of the subtraction and adding said target value to the result of the subtraction to thereby determine a motor control signal;
• an electric motor for providing an assist torque to said steering system;
• a motor drive section for driving said electric motor according to the motor control signal;
• and
• said steering torque differentiating section being arranged to output a differential value of a component of the steering torque which is free from a component near direct current and a high frequency component;
• wherein said steering torque differentiating section includes a band-pass filter that passes a component of the steering torque having a predetermined frequency band, and a differentiating circuit for achieving differentiating operation of said steering torque component passed through said band-pass filter, wherein said band-pass filter is a band-pass filter that passes a component of the torque signal having frequencies in the range of from 2 to 100 Hz.