Enhancing Simulator Fidelity Through Virtualized Vestibular Feedback

Abstract:
Prior work demonstrated that acceleration washout in motion simulators produces decay-rate sensing ambiguity within the vestibular system, forcing pilots to rely on visual cues for control. While Pilot Induced Oscillation Ratings (PIORs) for flight and simulation have been matched using different sensing thresholds, a quantitative basis for the 50% reduction in the visual decay-rate threshold has remained elusive. This paper provides evidence that pilots perceive decay rate proprioceptively through stick force during both flight and simulation, rather than through vestibular or visual channels. The residues of the stick-force sensitivity transfer function reflect the amplification or attenuation of neighboring zeros and poles; when these residues fall outside the human's 30 dB tactile sensory window, the resulting decay rate becomes imperceptible. Modeling reveals that stabilization via the visual channel in simulators produces dominant mode characteristics - decay rates, frequencies, and residues - that diverge significantly from vestibular-stabilized flight. The Virtual Vestibular Cueing (VVC) technique is introduced to tune the visual channel using pseudo-vestibular rate cueing, optimally aligning the simulated dominant mode with flight-validated residues and decay rates. A preliminary fixed-base study demonstrates that VVC synchronizes performance and subjective ratings by restoring this tactile-vestibular harmony. This work establishes that handling qualities are fundamentally an Information Theory problem: Level 1 ratings occur when the residue-to-decay gradient is tuned to map the dominant mode's physical 'elbow' onto the human sensory window. This paper establishes that perceptual fidelity is not determined by the closed-loop vehicle residues, but by the force sensitivity residues. By identifying the stick-force channel as the superior conduit for this mapping, VVC allows designers to restore informational integrity in virtual environments across all axes of aircraft dynamics. VVC ensures that the visual channel supports a control strategy where the tactile feedback remains within the human sensory window, preventing the 'wrong reading' that leads to simulator-to-flight rating mismatches.

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