| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power steering system capable of imparting a steering assist force of a motor in both turning direction and turning-back direction even if a torque sensor cannot detect a steering torque, and capable of imparting especially a proper assisting force while preventing an excessive turning along the turning direction. <P>SOLUTION: When an abnormality of a torque sensor 20 is detected by an abnormality detecting part 80, a motor 24 is driven on the basis of a rotational angle θr detected by a resolver 58 and an assist current characteristic. During driving, an assist current Ia which drives the motor 24 is controlled to be smaller as a rotational angular speed, which is calculated on the basis of the rotational angle θr, becomes larger. Consequently, an excessive turning along the turning direction is prevented while a proper assisting force is imparted. <P>COPYRIGHT: (C)2012,JPO&INPIT |
