Evaluation of a motion fidelity criterion with visual scene changes

An experiment examined how visual scene and platform motion variations affe cted a pilot's ability to perform altitude changes. pilots controlled a hel icopter model in the vertical asis and moved between two points 32-ft apart in a specified time. Four hf tors were varied: visual-scene spatial freque ncy, visual-scene background, motion-filter gain, and motion-filter natural frequency. Drawing alternating black and white stripes of varying widths b etween the two extreme altitude points varied visual-scene spatial frequenc y. The visual-scene background varied by either drawing the stripes to fill the entire field of view or by placing the stripes on a narrow pole with a natural sky and ground plane behind the pole. Both the motion-filter gain and natural frequency were varied in the motion platform command software. Five pilots evaluated all combinations of the visual and motion variations. The results showed that only the motion-filter natural frequency and visua l-scene background affected pilot performance and their subjective ratings. No significant effects of spatial frequency or motion system gain were fou nd For the values examined in this tracking task. A previous motion fidelit y criterion was found to still be a reasonable predictor of motion fidelity .