In telepresence and teleaction (TPTA) systems, the transmission of haptic signals puts high demands on the applied signal processing and communication procedures. When running a TPTA session across a packet-based communication network (e.g., the Internet), minimizing the end-to-end delay results in packet rates of up to the applied sampling rate of the local control loops at the human system interface and the teleoperator. The perceptual deadband data reduction approach for haptic signals successfully addresses the challenge of high packet rates in networked TPTA systems and satisfies the strict delay constraints. In this paper, we extend the underlying perceptual model of the deadband approach by incorporating psychophysical findings on human force-feedback discrimination during operators' relative hand movements. By applying velocity-dependent perception thresholds to the deadband approach, we observe further improvement in efficiency and performance due to improved adaption to human haptic perception thresholds. The psychophysical experiments conducted reveal improved data reduction performance of our proposed haptic perceptual coding scheme without impairing the user experience. Our results show a high data reduction ability of up to 96% without affecting system transparency or the operator's task performance.

Telepresent tasks involve removal of the human operator from an immediate working area and relocation to a remote environment that offers the operator all necessary control features. In this remote location, the operator must be provided with adequate feedback information such that the task at hand can be effectively executed. This research explores the effectiveness of various feedback methods. More specifically, graphical feedback in the form of video streamed images is compared against rendered 3D models, the overall effectiveness of haptic feedback is analyzed, and the influences of sensory augmentation and sensory substitution are examined. This study involved 48 participants, each of whom executed a simple clockwork assembly task under various feedback mechanisms. The results support the use of 3D models as opposed to live video streams for graphical presentation, utilization of haptic feedback (which was found to significantly enhance operation effectiveness), and the use of sensory augmentation and substitution under specific circumstances.