Ergonomic Assessment of Hand-Transmitted Vibration on the Human Based on MEMS Accelerometer

Abstract

Exposure to vibration affects every organ in the human body, leading to resistance and potential health hazards. Hand-transmitted vibration (HTV) is an occupational hazard in industries, causing hand-arm vibration syndrome (HAVS) and vascular, neurological, and musculoskeletal symptoms. Continuous monitoring is essential to prevent these risks. Therefore, a micro-electro mechanical systems (MEMS) based accelerometer vibration monitoring device is indigenously developed for continuous monitoring. The developed device has two units as controller unit which can be worn on individual hand and the sensor unit where the sensor is placed between the tool and palm. The acquired data is processed to determine parameters such as frequency weighted root mean square (rms) value (ahv) in the three directions x, y, z (ahwx, ahwy, ahwz) and exposure action value (EAV) or A(8) according to ISO-5439 standard. The study involved ten participants subjected to a hand-held drilling operation, with sensors placed as per ISO 8662-3 standard. The participants were allowed to drill continuously for up to 5 minutes. In this study, the effect of using different glove materials was analyzed keeping the posture, feed rate and the drill material constant. The HTV exposures of thirty participants were measured under different conditions (barehand, wearing nylon, rubber, and leather gloves) while drilling teak wood using an impact drill. The total frequency-weighted rms acceleration magnitude (ahv) while wearing nylon, rubber, and leather gloves was reduced by 16.78%, 30.91% and 23.78% when compared to barehand. The A(8) or exposure action value (EAV) has a reduction effect when gloves are used. The reduction was 12.84%, 35.85%, and 22.36% for nylon, rubber and leather when compared with barehand, respectively. The most significant vibration amplitudes occurred at frequencies of 100 Hz and 1000 Hz. The study showed that using rubber gloves reduces the vibration exposure action value and can effectively improve the efficiency of the drill operator. The developed device is low-cost and helps in continuous monitoring of HTV exposure and alerts workers of highvibration dosages that might cause vascular, neurological, and musculoskeletal disorders.