Transparency improvement of force-reflecting teleoperation over time-varying network delays

In this paper, we carry out a transparency (i.e., haptic realism) analysis and propose a haptic synchronization scheme for a force-reflecting teleoperation over time-varying network delay. Although previous researches proposed several haptic synchronization schemes to efficiently compensate for delay jitter, defining a proper synchronization delay for transparency improvement remains a challenge. Therefore, the transparency analysis quantifies the force feedback distortion caused by network delay and packet loss, and predicts the maximally allowable delay and loss for predefined transparency requirements. In order to minimize the force feedback distortion, the proposed haptic synchronization scheme controls the playout times of the delayed transmitted haptic events based on the transparency analysis. According to simulation and experimental results, the transparency analysis provides an acceptable quantification method about haptic interaction quality with respect to network delays and packet losses. It is also verified that the proposed scheme guarantees more transparent haptic interaction than existing synchronization schemes tailored for networked haptics.