Turning radius is calculated from steering angles of steering-wheels and
articulation angles of respective frames, and the steering-wheels are
automatically rotated faster than rear-wheels based on the turning radius,
the revolution number of the rear-wheels, engine speed of an engine and a
speed range of hydraulic motors, so that conventional trouble for
manipulating operation lever etc. while turning a motor grader and
skill-requiring work for adjusting the revolution number of the
steering-wheels in accordance with the revolution number of the
rear-wheels can be eliminated, thereby easily and accurately controlling
the revolution number of the steering-wheels and securely preventing
tight-corner braking phenomenon.
