Abstract
A prototype trailer-mounted mechanical drawbar control system was developed to facilitate the operation of a tractor-trailer combination (TTC) in greenhouse. It was designed to solve the problems of jackknifing and zigzagging of the TTC when driving in a reverse direction and the large turning radius on sharp curves and narrow roads when going forward. The prototype performance was compared to the conventional drawbar hitching system. The results showed that it attained a straight reverse direction at a minimal yaw rate of 0.025-0.05deg/s while the conventional system was observed to be on zigzag path when controlling the steering wheel and jackknifed when steadily held. A reduction in the turning radius and TTC track width of 16 and 20%, respectively, were attained for a 360 degree turn at a maximum tractor steering angle of 42 degrees.
