Analysis of annoying shocks transferred from tractor seat using vibration signals and statistical methods

In many developing countries, agricultural tractors are employed for different field operations and transportation along rural roads where the operator is exposed to high levels of harmful vibrations from the tractor seat. In case of the vibrations transferred to the operator's body, the vibration signal form and the number and type of the shocks have been neglected in related literature. This article is focused on modern approaches to analyze tractor and car seats vibrations which have been ignored in many standards guidelines. For this purpose, examining a case study, kurtosis and skewness approaches were used to evaluate the vibration signals generated by a tractor seat. Further, an innovative model was developed to evaluate the effect of the vibrations, in terms of vibration intensity and signal form, on the operator. Average percentage of vibration transfer from the engine to feet platform was estimated at 31%. It could be concluded that, ground roughness generates vibrations within the frequency range of 0-30 Hz, while the engine causes vibrations at some frequency ranging within 50-200 Hz. Kurtosis could better present the difference between the two signals. The results indicated that, when considered independently, the values of RMS, VDV and kurtosis cannot well represent differences in vibration signals parametrically. However, the novel approach, when used as a benchmark for comparison, showed the differences between the signals at high accuracy.