Ergonomic Assessment of Multi Calibre Individual Weapon System in Virtual Reality Platform

Abstract

     The primary objective of the study was to assess the compatibility of multi calibre individual weapon system (MCIWS) with the shorter, medium and larger individual users of Indian Army. Three dynamic digital human models (DHM) 5thp, 50thp, 95thp army pooled (AP) population were considered to accommodate wide range (more than 90 per cent) of the army population for ergonomic analysis of the weapon system with the help of digital human modelling software Jack. Solid model of MCIWS which was in Parasolid file format X_T (*.x_t) was imported into NX5 (solid model design software) and subsequently converted to JT (*.jt) format. This solid model was later translated into Jack 5.0.1 environment. Standing, squatting and crawling with the weapon were adopted for the study. Angular deviations of important joints, posture prediction using OWAS, and comfort discomfort assessment using Dreyfus 3D method were carried out in the study. The result of the study revealed that the operation in squatting and crawling conditions may increase postural load on neck, shoulder and upper arm. The pistol grip size, shape and contour are acceptable for the taller population. Removal of corrugated gripping surface, reduction of grip diameter and space adjustment for gloves use will be effective for optimal use. The position and size of fore grip seemed suitable for the taller users. Sight system could be accessed by all three user populations. It is advised to avoid holding the weapon for long duration with hands to prevent overuse injury or undue fatigue.