Simulating believable forward accelerations on a Stewart motion platform

Here we present a study where human participants rated the believability of forward accelerations simulated with a hexapod motion platform equipped with a projection screen. Visual forward accelerations were presented together with brief forward surge translations and backwards pitches of the platform, and synchronous random up-down movements of the camera in the visual scene and the platform. The magnitudes of all of the parameters were varied independently across trials. Even though we found a high variability between participants, most believable simulation occured with strong visual accelerations combined with backwards pitches of the platform which approximately matched the visually simulated acceleration. This was contrary to a previous study, which had found most believable simulation when the platform movements simulated a much smaller acceleration than what was shown visually. Furthermore, surge translations increased believability if they qualitatively matched the magnitude of visual acceleration. The acceleration-deceleration profile of the surge translation and the magnitude and frequency range of the up-down movements had little effect on the believability. When strong visual acceleration cues were given, most participants reported trials as realistic even when the platform tilt rate was above thresholds for the vestibular canals reported in literature. These results can be used to optimize motion cueing algorithms for the simulation of linear accelerations in motion simulators