Adjusting Haptic Guidance to Idiosyncratic Visuo-Haptic Matching Errors Improves Perceptual Consistency in Reaching

When subjects reach for a visual target with their unseen hand, they make systematic errors (visuo-haptic matching errors). Visuo-haptic matching errors are idiosyncratic and consistent over time. Therefore, it might be useful to compensate for these subject-specific matching errors in the design of haptic guidance to make the guidance perceptually consistent with the visual information. In this study, we investigated whether compensating for visuo-haptic matching errors results in better perceptual consistency in a reaching task. Subjects (N = 12) had to reach for visual targets with the handle of a haptic device (PHANToM Premium 3.0/6DoF) held in their unseen dominant hand without guidance, with haptic guidance toward the target position, or with haptic guidance toward the position they would reach for according to their idiosyncratic visuo-haptic matching error. We found that the distance between the aiming point of the guidance and the reached end position was smaller for the guidance toward the idiosyncratic matched positions, suggesting a larger perceptual consistency. Adjusting for idiosyncratic visuo-haptic matching errors seems to have benefits over guidance to the visual target position.