David W. Tack

Helmet accommodation analysis using 3D laser scanning

A method used to determine the probable population accommodation of a helmet sizing system is described. The method involves the use of 3D laser scanning, as a means of measuring helmet standoff distance (distance between the inside of the helmet and the skull), and the selection of a representative sample of test subjects. The laser scanner and the software developed to calculate standoff distance proved to be an excellent tool for the assessment of helmet fit. The main advantages include ease of use and visualization of problem areas. This 3D-analysis method gives designers objective evidence of the need for design changes as well as an idea of what these changes should be. A comparison was made between standoff distance results obtained from the scanner and those obtained using a physical measurement method (a probe). Although discrepancies were found between the two, sources of errors intrinsic to both methods make it difficult to determine which of the two methods yielded the truest standoff distance. Analysis of the comparison data shows laser scanning to be slightly more conservative than the probe method for standoff distance purposes, i.e. erring on the side of safety.

A Preliminary Investigation of the Effect of Protective Clothing Weight, Bulk and Stiffness on Combat Mobility Course Performance

Soldier loads continue to rise in response to new technological capabilities and emerging threats. However, literature addressing the extent to which load mass properties affects operational task performance and mission outcome is sparse. The objective of this preliminary study was to quantify the effect of PPE mass properties (weight, bulk and stiffness) on combat mobility, as measured using the standardized Load Effects Assessment Program (LEAP) course. Twenty-four soldiers completed the LEAP course in three clothing and individual equipment (CIE) configurations (UE: unencumbered; FFO: full fighting order (FFO) without body armour; and FFO+: FFO with body armour). Significant differences between clothing conditions were revealed for LEAP performance metrics (overall course time). Regression analysis revealed significant relationships between overall mobility performance and condition mass properties of weight, bulk, and stiffness. Outcomes will influence the design of future CIE and future research in this area.

Combined Task and Physical Demands Analyses towards a Comprehensive Human Work Model

Task analyses and physical demands analyses are combined to identify common and extreme postures and postural sequences, durations, frequency, and forces for Griffon Helicopter aircrew tasks, mission phases, and whole missions. The result is a comprehensive model of tasks and associated physical demands from which one can estimate the accumulative neck loads and moments caused by Night Vision Googles usage. Combining task and physical demands analyses yields a methodology for building a model of human work where information processing and physical demands are equally important for finding effective solutions to work issues.

Comparison of helmet-mounted display designs in support of wayfinding

The Canadian Soldier Information Requirements Technology Demonstration (SIREQ TD) soldier modernization research and development program has conducted experiments to help determine the types and amount of information needed to support wayfinding across a range of terrain environments, the most effective display modality for providing the information (visual, auditory or tactile) that will minimize conflict with other infantry tasks, and to optimize interface design. In this study, seven different visual helmet-mounted display (HMD) designs were developed based on soldier feedback from previous studies. The displays and an in-service compass condition were contrasted to investigate how the visual HMD interfaces influenced navigation performance. Displays varied with respect to their information content, frame of reference, point of view, and display features. Twelve male infantry soldiers used all eight experimental conditions to locate bearings to waypoints. From a constant location, participants were required to face waypoints presented at offset bearings of 25, 65, and 120 degrees. Performance measures included time to identify waypoints, accuracy, and head misdirection errors. Subjective measures of performance included ratings of ease of use, acceptance for land navigation, and mental demand. Comments were collected to identify likes, dislikes and possible improvements required for HMDs. Results underlined the potential performance enhancement of GPS-based navigation with HMDs, the requirement for explicit directional information, the desirability of both analog and digital information, the performance benefits of an egocentric frame of reference, the merit of a forward field of view, and the desirability of a guide to help landmark. Implications for the information requirements and human factors design of HMDs for land-based navigational tasks are discussed.

Helicopter Aircrew Cumulative Neck Loads from Integrated Task and Physical Demands Analyses

Task and physical demands analyses together can identify common and extreme postures and postural sequences, duration, frequency, and forces for Griffon Helicopter aircrew tasks and missions. A tasks and associated physical demands model was developed to estimate neck loads caused primarily by Night Vision Goggle usage. This integrated task and physical demands analysis was used to assess various solutions such as counterbalance or lighter helmets.

Investigation of alternative organizational structures for a digitized platoon

To evaluate the effect of digitization on platoon effectiveness and investigate the suitability of different platoon structures, a twelve-day field trial was undertaken with a Company of light infantry at Fort Benning, Georgia. Test missions were conducted in both day and night conditions, in wooded and urban terrain environments, in each of three organizational structures, with and without digitization. The three different organizational structures included our current in-service 8-man Section, a 13-man USMC squad, and a distributed model comprising six four-man teams. Results of this study confirmed that the effectiveness of a dismounted platoon is significantly enhanced by the use of select digital enhancements in the areas of navigation, situation awareness, communications, and command. During night operations, digitally-enabled capabilities were the difference between mission success and failure. None of the organizational structures tested proved to be universally better than the others at optimizing the benefits of digitally-enhanced capabilities, although each had their strengths and weaknesses. However, considerable insights were gained in the organizational structure issues of distributed small unit command and control, swarming formation tactics, and the tactics, techniques, and procedures necessary to employ small units effectively in a NCW environment.