Operatorʹs Fatigue in Field Operation of Hand Tractors

A hand tractor was modified to enable operation in a seated position. The physiological effects of the new seated position were compared with the effects of the standard design where the operator must walk behind the machine. The study was conducted in three operations, namely, transportation on a tarmacadam road, rota-tilling and rota-puddling of the hand tractor under different field conditions. Parameters such as vibration intensity in root mean square (rms) acceleration, heart rate, oxygen consumption rate and work-related body pain of operators were evaluated to study the fatigue on the operators. The energy expenditure rate was computed for various operations. The experiments were statistically designed and replicated. The results indicate that vibration intensity in rms acceleration in all the gear settings and all the conditions was minimum in the range of 1750–1850 min−1. The vibration intensity in rms acceleration was observed maximum as 45 m s−2 without the seat whereas this value was 20 m s−2 with the seating arrangement. It was observed that the seating posture requires about 25% less energy in transportation, 29% in rota-tilling and 10% in rota-puddling as compared to walking behind. The work-related body pain was also reduced on an average by 27% due to seating arrangement.