A Neurophysiological Evaluation of Cognitive Load during Augmented Reality Interactions in Various Industrial Maintenance and Assembly Tasks.

Augmented reality (AR) has been shown to improve productivity in industry, but its adverse effects (e.g., headaches, eye strain, nausea, and mental workload) on users warrant further investigation. The objective of this study is to investigate the effects of different instruction methods (i.e., HoloLens AR-based and paper-based instructions) and task complexity (low and high-demanding tasks) on cognitive workloads and performance. Twenty-eight healthy males with a mean age of 32.12 (SD 2.45) years were recruited in this study and were randomly divided into two groups. The first group performed the experiment using AR-based instruction, and the second group used paper-based instruction. Performance was measured using total task time (TTT). The cognitive workload was measured using the power of electroencephalograph (EEG) features and the NASA task load index (NASA TLX). The results showed that using AR instructions resulted in a reduction in maintenance times and an increase in mental workload compared to paper instructions, particularly for the more demanding tasks. With AR instruction, 0.45% and 14.94% less time was spent on low- and high-demand tasks, respectively, as compared to paper instructions. According to the EEG features, employing AR to guide employees during highly demanding maintenance tasks increased information processing, which could be linked with an increased germane cognitive load. Increased germane cognitive load means participants can better facilitate long-term knowledge and skill acquisition. These results suggested that AR is superior and recommended for highly demanding maintenance tasks since it speeds up maintenance times and increases the possibility that information is stored in long-term memory and encrypted for recalls.

Experimental evaluation of impact-resistant gloves using surrogate hands.

Injuries to the hand and fingers with varying degrees of severity are widespread in industries such as mining and oil and gas production. This study presents the results of tests carried out to measure the impact performance for commonly used impact-resistant gloves (metacarpal gloves). Sets of surrogate hands made out of a 3D-printed skeletal structure and soft tissues represented by synthetic gel were manufactured and subjected to controlled impact tests. The calibration and validation of the surrogates were based on impact response data reported previously for cadaveric specimens. Calibrated surrogate hand specimens were tested to assess the impact protection of typical metacarpal gloves. Each type of metacarpal glove provided different levels of protection measured by the decrease in the peak impact reaction force and the fractures detected after the impacts. Results indicated that surrogate specimens suffered fractures in 77% and 33% of the impacts for unprotected and protected hands, respectively.

Experimental evaluation of protected and unprotected hands under impact loading.

Hand injuries are a significant problem in many industries with relatively high incidence rates and injury severity. Many workers are required to wear impact protective gloves to protect their hands from impact-related hazards. This research presents the results of an experimental quantification of metacarpal gloves performance subjected to controlled impacts. Thirteen cadaveric hands were used to conduct a set of controlled impact tests on protected and unprotected hands. The controlled impacts targeted the proximal interphalangeal (PIP) joints, the metacarpophalangeal (MCP) joints, and the middle section of the metacarpal bones. Two types of metacarpal gloves commonly used in mining and oil and gas operations were selected for the tests. These gloves include different material and protection configurations on the dorsal side of the hand. The performance of selected gloves was quantified using the maximum reaction force to the impact and number of bone fractures. A total of 191 impacts produced 108 fractures, from which 71% corresponded to the unprotected hands and 40% to the protected hands. Depending on the impact position and type of glove used, the effect of protection ranged from no change up to a 23% reduction in peak reaction force.