Studies on the Human Engineering of Tractor Operation (1)

Effects of the Visual Field and the Visual Distance on Parallel Travelling

Abstract

To study the effects of the visual point of the tractor operator an experiment was carried out by several different operators using walking type tractor equipped with apparatus for limited visual point. The travel experiment was carried out on a field with level road of soil and a rotary tilled field. The trial apparatus for recording travel trace which was manufactured and the travel trace was recorded. The experiment was done with the visual point distance of 2-30m and the travel speed of 0.2-2.3m/sec, for the cases of limited and unlimited. The results obtained are summarized as follows.
1) According to the experiment of limited visual field, when the visual distance was short, the visual angular velocity of the operator was large. It was difficult to predict the travel direction of the tractor, and an operater could not drive accurately. When the visual distance was short, the travel speed therefore needed to be slowed.
2) When the visual distance was long, the visual angular velocity of the operator's eyes was small, the travel direction of the tractor could be predicted only for the fair front, and an operator could not drive accurately. Therefore, when the visual distance was long, the travel speed must be fast.
3) It was recognized that there was a optimum speed for driving tractor accurately. It was recognized that the most moderate speed was decided by the travel speed of the operator when operation was difficult, and decided by the visual distance when operation was easy.
4) The difference in the steering technique of the operator was small for the cases of the limited the visual field, that was large for the cases of the unlimited the visual field.