  When coupled with additional degrees of freedom, centrifuge-based motion
platforms can combine the agility of hexapod-based platforms with the ability
to sustain higher G-levels and an extended motion space, required for
simulating extreme maneuvers. However, the false and often nauseating
sensations of rotation, by Coriolis effects induced by the centrifuge rotation
in combination with rotations of the centrifuge cabin or the pilot's head, are
a major disadvantage. This paper discusses the development of a motion filter,
the Coherent Alignment Method (COHAM), which aims at reducing Coriolis effects
by allowing small mismatches in the G-vector alignment, reducing cabin
rotations. Simulations show that as long as these mismatches remain within a
region where humans perceive the G-vector as 'coherent', the Coherent Alignment
Zone (CAZ), the cabin angular accelerations can indeed be reduced. COHAM was
tested in a high G-maneuver task with a fixed CAZ threshold obtained in a
previous study. It was experimentally compared to an existing motion filter,
using metrics such as sickness, comfort and false cues. Results show that
sickness, dizziness and discomfort are reduced, making the centrifuge sessions
more bearable. It is recommended to further improve the filter design and
tuning, and test it with more fighter pilots.
