| 摘要 |
PURPOSE:To improve the stability at the time of handling a steering wheel back. CONSTITUTION:When a front-wheel steering mechanism 14 and a rear-wheel steering mechanism 18 are linked up by such a mechanical linkage as an intermediate shaft 52 and front wheels 12 are in a neutral position, rear wheels 16 is set down to this neutral position without fail. A steering ratio thetaS serving as the rate of a rear-wheel steering angle thetaR with a front-wheel steering angle thetaF is changed by a steering ratio changing mechanism 20 assembled in the mechanical linkage. The steering ratio thetaS is determined by a steering characteristic of thetaS=C1+C2.Y, by way of example. Among them, C1 is a fundamental steering characteristic item, Y a yaw rate and C2 a control gain, respectively. When a steering wheel is handled back toward the neutral position, the steering ratio 6 S is compensated in the direction of a phase quantity increment. At time of handling the steering wheel back from the neutral position, it is desirable that the steering ratio is compensated in the direction of a phase quantity decrement and turnability is improved, rehandling and handling back of the steering wheel are judgeable on the basis of a steering angle thetaH and a steering angular velocity d thetaH, by way of example. |
