The influence of handle-avatar mapping uncertainty on torque fidelity of 6-DOF haptic rendering

The handle-avatar mapping from the handle of a desktop haptic device (i.e., the handle) to the virtual tool (i.e., the avatar) is subject to several uncertainties, including uncertain held positions of the human hand, un-modeled hand position on the virtual tool, and difference between the shape of the virtual tool and that of the physical handle. The influence of these uncertainties on the force/torque fidelity of 6-DOF haptic rendering is analyzed in this paper. A model of force/torque error induced by these uncertainties is introduced to measure the influences under different contact scenarios. A method based on adding a handle-hand avatar to the virtual tool is proposed to reduce the uncertainties and thus to improve simulation fidelity. Psychophysical experiments were carried out. Experiment results show that the subjective feeling of the human operator is consistent with the theoretical analysis results. Most subjects can feel the increase on torque fidelity after using the proposed method.