Perception of stiffness during interaction with delay-like nonlinear force field

Abstract

The perception of linear stiffness, as well as delayed linear stiffness, was studied extensively during the last decades. In this study we set to explore the effects of non linear relation between force and position on perception of stiffness. We designed a state dependent non-linear force field, similar to the previously explored delayed force field, which is essentially a piecewise linear force field depending only on the position and the direction of movement and not on time. We show that the stiffness of this force field is overestimated. We suggest a model based on the inverse of the slope of a regression of position over force in order to explain these behavioral results, which indirectly implies that force control is used during this exploratory probing. © 2010 Springer-Verlag.