| 摘要 |
<p>In an electric power steering system (1), when a motor rotation angular speed É and a motor rotation angular acceleration ± of a steering assisting motor (21) both exceed corresponding predetermined values És and ±s, respectively, an abnormal external force application-determining section (50) determines that an external force equal to or greater than a predetermined value is applied to a steering mechanism, and sets an abnormal external force application determination flag (FLG) to 1. When the abnormal external force application determination flag (FLG) is 1, a d-axis electric current command value-calculating section (41) activates a motor rotation angular speed-reducing section (100) and performs field-strengthening control based on a motor rotation speed/d-axis electric current command value map.</p> |
