A human factors evaluation of two different machine control systems for log loaders

The implement movement in today's mobile, heavy machinery does not correspond in a one-to-one proportion with hand control movement. This lack of correspondence places high perceptual and psychomotor demands on the operator. The objective of this study was to evaluate the human factors of two different machine control systems on a log loader in a controlled field setting. The traditional joint control system was compared with a co-ordinated control system. The two machines were tested on ten novice and six experienced operators. Operator performance was based on the time required to complete a task sequence, as well as reaction time. The results show that the novice operators performed significantly better in co-ordinated mode than they did in joint mode, whereas the experienced operators performed better in joint mode than they did in co-ordinated mode. Results indicate, however, that it would not take long for experienced operators to transfer their skills from joint control to co-ordinated control.