Dynamic Response of Human Body Seated on a Tractor and Effectiveness of Suspension Systems

High amplitude vibrations, in the 0.5 - 11 Hz frequency range, are found to be harmful to tractor drivers. This paper deals with the analysis of vertical and pitch vibrations of the tractor - human occupant system. Our specific purpose is to determine the parameters and effectiveness of standard type suspension systems (provided to (i) both seat and front axle, (ii) seat only) so that the response of the human body parts to vibration are minimized. It is found that the standard type suspension provided to the seat alone is better than the other type and effective in reducing vertical and pitch vibration levels by 60% and 85% respectively, thus improving ride comfort to a considerable extent.