This work is important for all robotic systems and is most recently motivated by head mounted displays, such as the Oculus Rift. A head mounted display (HMD) is a device worn on the head that can display different images to each eye, providing a virtual 3D display. Common applications for HMDs include training and gaming, where the action takes place within a virtual environment. As the user moves in the virtual environment, the images displayed on the HMD are updated to show how the world looks from the user's position. To facilitate this operation, the head of the user is tracked, detecting the position and orientation, and thus providing the location within the virtual environment from where the display images should be generated.
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For an HMD we are interersted in the delay between when the head moves and when the images on the display are updated. This delay is caused by a series of steps, including sensing the motion, determining the new position, generating images for the user from that position, and actually displaying the images. The delay can cause the user to feel naseaus or unwell, feelings commonly referred to as "sim sickness". We seek to model the delay, characterize its distribution, and perform experiments where we control the delay in order to better understand its effect on sim sickness. Previous work has focused on constant latency as the causal factor of motion sickness. Our group has found that latency is not constant, but varies over time. Further, we have found that constant latency is not sickening, but varying latency is sickening. We have a unique laboratory paradigm in which we can manipulate the amplitude and frequency effects of latency and measure human motor performance and motion sickness.