Predictor Displays to Improve the Operator Performance for Agricultural Guidance-aid Systems

Abstract

GPS guidance-aid systems for agricultural vehicles have been around for several years. This article will focus on the interaction of the human operator with these systems. Since lateral dynamics of agricultural vehicles is of second order, in order to achieve acceptable performance in tracking the GPS signal, the human operator needs to provide lead compensation, resulting in increased task difficulty. This study was carried out to investigate whether the use of predictor displays can reduce the task difficulty and improve the task performance. Two predictor displays were developed to show to the operator: i) projected error at some look-ahead distance, and ii) current error as well as the tractor heading. These displays were compared with a baseline display, which showed the current error, in a tractor simulator. The results indicated that predictor displays improved the measures of task performance and difficulty by a factor of two or more. With predictor displays, the differentiation operation is basically performed in the display rather than by the human operator, resulting in lower task difficulty and improved task performance.