Abstract
This paper describes an investigation into the effects of displayed error scaling on manual control behavior during compensatory roll-axis tracking. Previous experiments have indicated that for compensatory displays that, similar to an artificial horizon, present the roll tracking errors in rotational form, the deviations for typical quasi-random forcing function signals are comparatively small and difficult to perceive. This was found to lead to degraded tracking performance and lower crossover frequencies than would be expected. To investigate this, a roll-axis tracking experiment has been performed in which the scaling of the presented tracking errors was varied from 0.5 to 5 times the true tracking error. In addition, both double integrator dynamics and typical conventional roll dynamics of a small jet aircraft were considered in a mixed experimental design. The main hypothesis for this experiment was that increased scaling of the presented roll-axis tracking error would result in improved tracking performance and correlation of manual control inputs with the target forcing function signal. In addition, these effects were hypothesized to be more pronounced for the more difficult double integrator dynamics. For both controlled elements, both tracking performance and linearity of pilot control were indeed found to increase with increasing display gain, leveling of for the highest considered display gains. Further analysis of manual control behavior using McRuer et al.’s Precision Model revealed marked changes in the adopted control strategy due to changes in displayed error scaling, which were found to be highly similar for both controlled elements.
