Ergonomics Study of a Helmet-Mounted Augmented Reality System for Coal Power Plant Workers

Augmented reality (AR) is a technology that combines real and virtual information presented to the user in an interactive way in real time. The Microsoft HoloLens and RealWear HMT-1 are two common types of head-mounted AR available to industrial field workers. These two AR systems were tested on how they affected indicators of eye strain and forces of the neck and shoulder muscles for electric utility power plant operators while they performed five routine inspection tasks using coal burning equipment. The inspection tasks were conducted under three conditions: HoloLens, HMT-1, and absence of AR (normal). The duration of the inspection tasks ranged from an average of 10 to 28 s. Twelve experienced power plant operators participated in the study. Surface electromyography (sEMG) of the right and left sternocleidomastoid, splenius, semispinalis capitis, and upper trapezius muscles were measured, and a small camera recorded blink rate of the right eye. Results show there were generally no significant differences in 50th and 90th percentile sEMG between the three conditions for all eight muscles. Although blink rate did not vary significantly between the experimental conditions, a trend appeared that showed average HoloLens blink rate lower than the HMT-1 and No AR (~ 4.5 blinks/min;28% decrease). Lower blink rate is a risk factor of eye strain, and data from this experiment suggest that the HoloLens may cause eye strain. Longer durations of sustained HoloLens usage must be tested to determine whether the HoloLens presents risk of eye strain to electric utility field workers