Why delay breaks the feedback loop
Haptic teleoperation depends on a tight loop: the operator moves, the robot moves, the robot feels contact, and that force is fed back to the operator almost instantly. Over a low-latency local connection this loop feels natural. Over a high-latency link, such as a long-distance network connection or, in the extreme, a link to space, that same loop can become unstable. Delayed force feedback can cause an operator to overcorrect, and the system can start to oscillate or, in more extreme cases, apply damaging force before the operator even perceives that contact has occurred.
The underlying problem is that force feedback is fundamentally different from displaying a delayed video frame. A delayed image is merely stale information. Delayed force feedback creates a mismatch between what the operator's hand is doing right now and what the remote robot is currently experiencing, and because force loops involve continuous, high-frequency exchange of energy between operator and robot, even small delays can undermine the stability of that exchange rather than just its timeliness.