A New Methodology for Evaluating Guidance Systems for Agricultural Vehicles

Evaluation of new technologies in agricultural machinery guidance is very important and can help producers choose the right equipment for their applications. At present, comparison between different guidance systems has typically been based on the amount of guidance error (i.e., the deviation of the vehicle from the desired path). This paper proposes a new methodology for evaluating these guidance systems. An RTK-GPS was used to record the exact location of a tractor while the operator used one of seven lightbar guidance systems to drive along parallel passes in the field. Frequency-domain analysis of the tractor path was used to compare the performance of the seven systems. Fourier analysis of the tractor path was performed by dividing the changes in the tractor path into low-, medium-, and high-frequency changes. Guidance systems with lower driving error have more high-frequency changes in the tractor path. This means that there is a tradeoff between the driving accuracy and operator workload. It is suggested that a comparison of the frequency spectrum of the tractor path can be used to better evaluate or compare agricultural guidance systems.