Perception of haptic force magnitude during hand movements

Haptic interfaces are used increasingly in medical systems and related applications, but relatively little is known on the effectiveness of these interfaces. This paper reports a study on the perception of haptic force magnitude during hand movements. Discrimination thresholds were determined for a reference force of 1.5N in five different directions (0deg, 45deg, 90deg, 135deg, and 180deg) with respect to the movement direction. We found that force discrimination thresholds detected were significantly higher during hand movement than those reported previously without hand movement, indicating that the perception of force magnitude is impaired by hand movement. The results also show there is no significant difference between the discrimination thresholds found for fast (28 mm/s) and slow (14 mm/s) hand movements. Finally, we found that the perception of force magnitude is impaired at a force direction of 45deg with respect to the hand movement, indicating the existence of an oblique effect.