An energy bounding approach for directional transparency in multiple degree-of-freedom haptic interaction

This paper presents an energy bounding approach (EBA) to enhance directional transparency while guaranteeing stability for multiple degree-of-freedom (DOF) haptic interaction. It was observed that the passivity condition for multiple ports may lead to some oscillations in some coordinate directions even though total energy is positive. The passivity condition, therefore, needs to be applied to each orthogonal coordinate. For guaranteeing stability in each orthogonal coordinate, the EBA is applied. For multiple-dof haptic interaction, however, the EBA in each coordinate may cause a problem that the direction of the rendered force vector is distorted. This problem can easily be solved by projecting the direction of the rendered force vector on its original direction. The validity of the proposed algorithm is shown by some experiments.