摘要 |
An apparatus (10) for use in turning steerable wheels of a vehicle (12) upon manual rotation of a steering wheel (14) comprises a front steering motor (36) coupled to a front steerable wheel (18) of the vehicle (12) for turning the front steerable wheel. A rear steering motor (66) is coupled to a rear steerable wheel (22) of the vehicle (12) for turning the rear steerable wheel. A position sensor (34) senses a rotational position of the steering wheel (14) and provides an output indicative of said rotational position. A controller (90) receives the output of the position sensor (34) and controls the front and rear steering motors (36, 66) to turn the front steerable wheel (22) in response to the output from the position sensor (34) indicating rotation of the steering wheel (14) in a first portion of a range of rotation of the steering wheel. The controller (90) also controls the front and rear steering motors (36, 66) to turn only the rear steerable wheel (22) in response to the output from the position sensor (34) indicating rotation of the steering wheel (14) in a second portion of the range of rotation of the steering wheel.
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