| 摘要 |
PURPOSE:To enhance operability of a four-wheel steering gear at intermediate and high vehicle velocities, by providing a controller for controlling a rear-wheel steering gear in accordance with rear-wheel steering angle characteristics relative to a front-wheel steering angle. CONSTITUTION:Front wheels 1, 1 and rear wheels 2, 2 are mechanically separated from each other, an output 4a from a front-wheel steering angle sensor 4 detecting a steering angle thetaH of a steering wheel 3 is inputted into a controller 10 for the rear-wheel steering gear, and the rear wheels 2, 2 are steered by the input signal. A point of inflection P1, P2... at which a steering ratio thetaR/thetaF is reduced is varied toward a smaller front-wheel steering angle thetaF as the vehicle velosity is increased, so that a G range is reduced with an increase is the vehicle velocity, and the rear-wheel steering angle thetaR reaches a limit value theta'R for a small front-wheel steering angle thetaF, thereby enhancing operability. In addition, a higher steering ratio is obtained for a higher vehicle velosity, whereby response characteristic at the time of a lane change at an intermediate or high vehicle velocity is enhanced. |
