On the discrimination of stiffness during pressing and pinching of virtual springs

In this paper, we study the perception of stiffness while pressing and pinching virtual springs. These exploration events are highly relevant for telerobotics, but their influence on stiffness perception is largely unexplored. Our study contributes to the understanding of the limits of stiffness perception for human-robot interactions. According to our experiments, mean Weber fraction values between 0.134 and 0.166 are obtained for a reference stiffness value of 200 N/m. Our results also show that the differential sensitivity for stiffness is not significantly affected by the actual exploration event. To test the constancy of the extracted Weber fraction values five further reference stiffness values are evaluated suggesting a constant stiffness sensitivity value in the range of stiffness between 135 and 390 N/m.