| 摘要 |
PURPOSE:To ensure the stability of a vehicle, particularly in a reverse phase range which is sensitive to change in rear wheel steering ratio, by restraining the speed of change in rear wheel steering ratio in accordance with the phase of rear wheel steering ratio to restrain change in the behavior of the vehicle in association with change in rear wheel steering ratio. CONSTITUTION:In a four wheel steering device in which the ratio of rear wheel steering is variable, and a rear wheel steering ratio having the same phase and a rear wheel steering ratio having the reverse phase are given to the control characteristic of rear wheel steering ratio, there are provided a phase discriminating means 1 for discriminating whether the rear wheel steering ratio has the same phase or the reverse phase, and a limiting means 2 for limiting the speed of change in rear wheel steering ratio. Further, there is provided a limiting value regulating means 3 receiving a signal from the phase discriminating means 1, for setting the limiting value by the limiting means 2 so that it is greater when the rear wheel steering ratio has the reverse phase than when the rear wheel steering ration has the same phase. Thereby it is possible to ensure the stability of the vehicle in the reverse phase range which is sensitive particularly to change in rear wheel steering ratio. |
