Translational vibration evaluation of tractor seats for ride comfort

Abstract

An investigation was carried out on tractor seat design for better operator comfort during operation. The project objectives were mainly aimed to increase the ride comfort by improving the seat suspension which is used in Indian tractors. Tests were conducted for haulage operation and also for field operation. During haulage operation tests were carried out onexisting seats used in Indian tractors with three new selected suspension systems of the two most selling models of MF 241 and MF 1035. The model MF 241 equipped with a existing seat is mostly used in India, while the model MF 1035 consists of exported benchmark seat (for comparison) which is a seat whose suspension appeared to majority of operators is used for more comfortable and rest three selected seat suspensions were replaced to same existing seat used in India. Tests were conducted with three different operators representing 5th, 50th and 95th percentile (SM1, SM2 and SM3) of the population of India. Best suspension system was selected, based on weighted RMS acceleration awx, awy, awz for each axis and the acceleration vector sum av performance. The values of weighted RMS acceleration awx, awy, awz, and acceleration vector sum av of different suspension systems were compared with exported benchmark seat as well as existing seat mostly used in India. The changes in the vibration peak along with speed were compared graphically. It was observed that the SP2 suspension gives better result amongthree selected suspensions. The results were comparable with exported benchmark seat in higher speed range which was available in developed countries.
Keywords: seat suspension, weighted R.M.S acceleration, spring constant