| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power steering device capable of appropriately controlling a motor on the basis of a rotational angular velocity of the motor. <P>SOLUTION: The electric power steering device calculates a rotational angular velocity of a motor on the basis of a motor equation. An approximation formula of the motor equation is calculated based on a running state of the motor and a counter-induced voltage constant of the motor equation is updated based on the approximation formula. The electric power steering device includes: a sensor for outputting a signal according to the operation of a drive unit to which a motor torque is provided; and a calculating unit for calculating a calculated value of the rotational angular velocity of the motor on the basis of an output signal of the sensor. The device also stores a measured voltage value and a calculated value of the rotational angular velocity of the motor when a measured current value of the motor is within a predetermined range, and calculates an approximation formula when a stored measured voltage value or a calculated rotational angular velocity value is not less than a predetermined value. <P>COPYRIGHT: (C)2013,JPO&INPIT |
