| 摘要 |
PURPOSE:To prevent the transverse slip of vehicles and ensure the small turning radius thereof to an available level by determining a steering ratio depending upon the slippery condition of a road surface and determining a rear wheel steering angle correspondingly. CONSTITUTION:A detecting means 5 for a road condition finds a slip condition attributable to the wetted and frozen road surface, and outputs a corresponding signal. Then, according to said detected signal and another signal from a car speed detecting means 1, a steering ratio operating means 2c calculates a primary steering angle ratio when the road is in a non-slippery condition, and a secondary steering angle ratio when the road is in a slippery condition. The result of the calculation is fed to an output means 3 as a determined steering angle ratio. And a control signal corresponding to the determined steering angle ratio, is outputted to a rear wheel steering mechanism 4 to set a rear wheel steering angle to the determined steering angle ratio. The secondary steering angle ratio in this case gives a steering value in the same phase as the front wheel at a relatively slow running speed, as compared with the primary steering angle ratio. Therefore, even when a coefficient of friction between the road surface and the wheels is small, the slip angle of vehicles does not become so large, thereby preventing a transverse slip and keeping the small turning radius as original. |
