| 摘要 |
PURPOSE:To attempt a precise control at high speed as well as improvement of steering responsiveness at low speed by providing a partition number correction means which makes a digital partition number corresponding to an unit rear wheel steering angle vary in such a way as to be small at low speed, but be great at high speed. CONSTITUTION:In a low speed range, an angular width corresponding to one pulse as an input rear wheel steering angle information for a feedback control is four times as much as that in a high speed range. And a motor 21 is controlled in such a way that an actual rear wheel steering angle information thetar of a certain width to be detected corresponds with a target rear wheel steering angle deltar. Namely, if a steering angle deltar is out of an angular width means by the information thetar, the rotational direction of the motor 21 is determined for outputting a rotational output signal to a circuit 21b whereby the motor 21 is suspended by a hold signal as soon as the angle deltar falls within the angular width of the information thetar. By the afore-said constitution, the angular width of the information thetar is made wider as speed becomes lower, even if a rear wheel steering mechanism 10 somewhat overruns by inertia after the hold signal has been outputted, the steering angle deltar does not come out of the angular width of the information thetar whereby the information thetar is small at high speed for enabling a precise control to be exerted. |
