Some of what one needs to know about using head-mounted displays to improve teleoperator performance

It is noted that a head-mounted display (HMD) system would be a useful teleoperator system display if it increased operator performance of the desired task but could degrade performance because of display update rate limitations and communication delays. 3-D tracking and pick-and-place tasks are simulated to characterize performance levels for a range of update rates and delays. How performance changes as the display is altered to maintain the update rate is also examined. The results of the update experiments indicate that performance levels degrade only slightly until the update rate is below 1 or 2 Hz. Attempts to maintain update rate by eliminating display features such as stereo and occlusion cues show that the presence of either cue alone is sufficient to maintain performance levels in the simple, short-term tasks considered. Delays also degrade performance in both manipulation tasks considered. These HMD performance problems are not lessened by the presentation of a predictive feedback display. Instead, the delay in the head movement tracking loop must be eliminated. >