| 摘要 |
A steer-by-wire vehicle steering system and method of controlling such a steering system when steering into and away from a steering stop. In one embodiment, the system includes a steering reaction device (55) including a fluid displacement mechanism (71), and a valve arrangement (95) operable to vary the steering reaction provided to the vehicle operator. In another embodiment, there is a "friction" reaction device (111) including an electromagnetic coil (115) which can have a varying signal (61) applied to it to vary the steering reaction the coil imposes on a movable member (113) of the device (111). In either embodiment, the reaction device includes a spring arrangement (93;131), such that rotation of the steering wheel (51) is in opposition to a spring force. In accordance with the method of the invention, as the operator steers into a stop, the reaction torque increases enough to prevent turning the steering wheel (51) further, but when the operator turns the wheel to steer away from the stop, the system senses the reversed direction of steering and reduces substantially the steering reaction which the operator senses.
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