Effects of Heave Washout Filtering on Motion Fidelity and Pilot Control Behavior for a Large Commercial Airliner

Abstract

Due to the significant translational heave motion at the pilot station associated with changes in aircraft pitch attitude, themotion cueing for aircraft pitchmaneuvering typically requires significant heave washout filtering. Previous studies that attempted to motivate choices in the motion cueing strategy for pitch maneuvering based on measurements of pilot behavior. For the small conventional aircraft considered in these studies, the results indicated that, despite the fact that pilots were found to adapt their control strategy to changes in heave cueing, the pitch rotation had a dominant influence on pilot behavior during pitch tracking. For large commercial airliners, a relevant application of this research as a lot of commercial pilot training occurs on moving-base simulators, the location of the pilot station is significantly further from the center of aircraft pitch rotation, yielding more pronounced heave motion cues during changes in pitch attitude. This difference, in addition to typically slower pitch dynamics that require more lead equalization, implies the best choice in motion cueing for large aircraft may be significantly different from what would be optimal for smaller aircraft. In this paper, an experiment is described in which pilot behavior is measured in a pitch attitude disturbance-rejection task with a controlled element and motion cueing conditions that are representative for a Boeing 747 aircraft. Different third-order heave washout filter settings were considered, in addition to a variation in the presence of 1-to-1 rotational pitch motion. Significant effects of the applied variation in pitch and heave motion cueing are observed, even though the effect of heave motion feedback is indeed found to be comparatively more important for larger aircraft. Furthermore, a heave motion filter that combined a low gain with low filter phase distortion was found to yield the least effect on pilot behavior, while for heave motion filters with a relatively high gain and high break frequency significantly larger contributions of motion feedback to pilot behavior were observed.