2 a C 014 Parison of Washout Filters Using a Human Dynamic Orientation Model

The Ormsby model of human dynamic orientation, a discrete time computer program, has been used to provide a vestibular explanation for observed differences between two washout schemes. These washout schemes, a linear washout and a nonlinear washout, were subjectively evaluated by Parrish and Martin. They found that the linear washout presented false rate cues, causing pilots to rate the simulation fidelity of the linear scheme much lower than the nonlinear scheme. By inputting the motion histories from the Parrish and Martin study into the Ormsby model, it was shown that the linear filter causes discontinuities in the pilot's perceived angular velocity, resulting in the sensation of an anomalous rate cue. This phenomenon does not occur with the use of the nonlinear filter. In addition, the suitability of the Ormsby model as a simulator design tool was investigated. It was found to be a useful tool in predicting behavior of simulator motion bases, even when the mechanical motion base is replaced by a computer simulation. Further investigation of the model could provide simulation designers with a tool to predict the behavior of motion bases still in the drawing board stage.