Opening the haptic loop: Network degradation limits for haptic task performance

For realtime teleoperation with haptic feedback, network-induced artifacts like delay, packet loss and lossy coding of haptic data deteriorate the operability of the system. We provide a systematic quantification of the limits within which, these network-induced degradations are tolerable for human task performance in executing a given haptic task. These limits are conservative in the sense that we do not account for any stabilizing approaches from control engineering to counter the impact of the network-induced degradations. Through experimental evaluation with a pursuit tracking task, we show that task performance is most affected by delay on the network and a strong lossy coding scheme. With statistical analysis we show that task performance is significantly decreased for one-way delay higher than 14 ms and strong lossy coding with a deadband parameter higher than 27%. For the given task, packet loss is found not to affect task performance significantly.