| 摘要 |
PURPOSE:To improve safety and drivability of a vehicle, when it is reversed, by executing a steering control in accordance with the reverse time steering ratio characteristic, which switches steering ratio from a reverse phase side to a same phase side following an increase of car speed while performing this switching in a very low speed region, when the vehicle is reversed. CONSTITUTION:An advance reverse decision part 54, which decides an advance or reverse condition from an output of a gear position sensor 51 detecting a meshing condition of a transmission gear, is provided, and being based on this decision result, the advance time or reverse time steering ratio characteristic is selected from a steering ratio characteristic memory part 56. While calculating a steering angle of a rear wheel in a rear wheel steering angle arithmetic part 57 from output signals of a steering angle sensor 52 and a car speed sensor 53 and from the above described steering ratio characteristic, and in accordance with the arithmetic result, a stepping motor 45 for steering the rear wheel is controlled. The above described reverse time steering ratio characteristic is set in a manner wherein it switches steering ratio from the reverse phase side to the same phase side following an increase of car speed while performing this switching in a very low speed region of a vehicle. |
