Much of the grassland in Japan and other countries
are in hilly areas where the farm tractor is used for
various tasks. However, working on hilly terrain can
cause discomfort to the operator, due to the effects on
body alignment. This also increases the fatigue of the
operator and thereby decreases the work efficiency with
time. Although much research has been conducted on
automatic guidance system for the farm tractor, most is
concerned with flat land