Elimination of Cross-dimensional Artifacts in the Multi-Dof Time Domain Passivity Approach for Time-delayed Teleoperation with Haptic Feedback

This paper extends the state-of-the-art multi-Dof time domain passivity approach (TDPA), leading to more flexible usability and improved user experience in time-delayed teleoperation. TDPA is an effective method to guarantee stable teleoperation in the presence of communication delay. As the TDPA has gained increasing attention, several studies have focused on extending the originally proposed one-degree-of-freedom (1-Dof) TDPA to multi-Dof. In this paper, we describe that the existing multi-Dof TDPA introduces additional distortions which do not appear in the 1-Dof TDPA. More specifically, motion in one direction can cause distortion (force fluctuation and position drift) even perpendicular to the motion. We name this phenomenon cross-dimensional artifact (CDA). The CDA leads to disturbed teleoperation control and degraded user experience. To address this issue, we first offer a deep analysis of this CDA. Then, we propose a projection-based multi-Dof TDPA extension and suggest a corresponding adaptation to eliminate the CDA. Subjective experiments show that the proposed adaptation is able to remove the distortions caused by the CDA and improve the user experience for sliding tasks and perceiving object surface features.