Biodynamic Feedthrough Models and Model-Based Cancellation for Touchscreen Dragging Inputs in Turbulence

Abstract

This paper applies model-based biodynamic feedthrough (BDFT) cancellation to a touchscreen dragging task during realistic vertical (vertical) and lateral (horizontal) aircraft turbulence, to mitigate erroneous turbulence-induced inputs. One-size-fits-all (OSFA) BDFT models were used to model the influence of turbulence accelerations on finger position, achieving average quality-of-fits of 61% and 69% in the vertical and horizontal screen directions, respectively. On average, 27% of the touch input error variance was mitigated these OSFA models, with individualized models providing only a marginal improvement (+4%). The application of OSFA models identified from a condition with equally-scaled vertical and horizontal motion (adjusted intensity) to the realistic turbulence condition did not significantly affect cancellation performance, indicating that BDFT models may not need to be adaptive to varying motion intensity. However, consistent with earlier work, BDFT dynamics were found to vary between vertical and horizontal finger movements, with BDFT dynamics exhibiting lower stiffness and a higher static gain for vertical BDFT. On average, the linear BDFT-related component of touch input errors contributed 41% of the overall error variance, indicating that current linear BDFT model may need to be extended to include nonlinear effects, such as varying finger friction.