| 摘要 |
PURPOSE:To improve the reliability of steering ratio control by driving a stepping motor even when a coil winding is disconnected. CONSTITUTION:A rear wheel steering angle sensor 98 is mounted on a stepping motor 5 and a coil winding disconnection sensing means 99 is provided in a stepping motor driving section 6. A controller 94 receives the disconnection sensing signal of each coil and outputs a current direction switching signal to the stepping motor driving section 6. In other words, when one coil winding is disconnected, a coil winding that has a relationship of inversion phase with the disconnected coil winding is excited in a polarity reverse to that at normal time. In addition, the driving pulse frequency is reduced and the torque decrease following the current direction switching is prevented. |
