Effects of network delay on a collaborative motor task with telehaptic and televisual feedback

Abstract

The incorporation of haptic interfaces into collaborative virtual environments is challenging when the users are geographically distributed. Reduction of latency is essential for maintaining realism, causality and the sense of co-presence in collaborative virtual environments during closely-coupled haptic tasks. In this study we consider the effects of varying amounts of simulated constant delay on the performance of a simple collaborative haptic task. The task was performed with haptic feedback alone or with visual feedback alone. Subjects were required to make a coordinated movement of their haptic displays as rapidly as possible, while maintaining a target simulated spring force between their end effector and that of their collaborator. Increasing simulated delay resulted in a decrease in performance, either in deviation from target spring force and in increased time to complete the task. At large latencies, there was evidence of dissociation between the states of the system that was observed by each of the collaborating users. This confirms earlier anecdotal evidence that users can be essentially seeing qualitatively different simulations with typical long distance network delays.

Variability-Aware Latency Amelioration in Distributed Environments

“…The authors concluded that participants adopt a move-and-wait strategy to synchronize their movements, consequently increasing the total time required to complete the task. This study, as well as other similar research [3] converge on the conclusion that, in addition to increased time-to-completion, task accuracy also suffers in setups with larger latencies. Furthermore, latency can result in oscillopsia, which is the perception that the visual world appears to swim about or oscillate in space [2].…”

“…While end-to-end delay has been clearly identified as a major impairment to DIVEs, jitter has recently been acknowledged as having an even greater impact [10,20,3]. Park and Kenyon [20] conclude that network latency jitter disarms compensatory prediction techniques otherwise available for known constant delay systems.…”

Evaluating ALPHAN with Multi-user Collaboration

“…There have been several attempts to study how the network conditions affect user interaction and cause instability in collaborative scenarios [10,11,12,13]. It is worth mentioning that most of the studies have been focused on only network delays, because they are the main cause of instability.…”

“…In a later research, the effects of varying simulated delay on a cooperative task has been studied and evaluated in [10]. During this experiment, the same time-delay compensator was used.…”

Simultaneous remote haptic collaboration for assembling tasks

“…Some researchers have studied the effects of delay or jitter on task performance and their acceptable performance limits [37,38]. The issue of "network-based force feedback" is addressed in [39].…”