Ergonomic Assessment of Self-Propelled Machinery Seats for Agricultural Workers

Excessive vibrations in self-propelled machinery engaged in agricultural farm operations cause mechanical failures and subject the operators to discomfort. Laboratory tests were carried out in a completely randomized design in a factorial arrangement (type of seat×engine, speeds×subject) with a view to evaluate the self-propelled machinery seat ergonomically. Various performance parameters like 1/3rd octave band vibration acceleration, Working Heart Rate (WHR), Oxygen Consumption Rate (OCR), Energy Expenditure Rate (EER) were measured during the operation of self-propelled machinery with different types of seats (SM-1 to SM-5) and statistically analyzed. The 1/3rd octave band vibration acceleration of self-propelled machinery was found to be lowest with SM-5 seat i.e. 0.983, 0.646, 1.019 m/sec2 and highest with SM-1 seat i.e. 4.21, 2.77 and 9.819 m/sec2 in X, Y and Z direction, respectively. It was observed that the vibration acceleration in Z direction is higher as compared to X and Y direction and vibration acceleration has a linear correlation with engine speed. The vibration acceleration and physiological parameters viz. working heart rate, oxygen consumption rate and energy expenditure rate of the subjects were found lesser for SM-5 as compared to other four seats at different engine speed for the self-propelled machinery. Different types of seat, engine speed and subject has statistically significant effect on 1/3rd octave band vibration acceleration, WHR, OCR and EER at 1% level.