EFFECTIVE PROFILE ESTIMATION FOR TRACTOR DYNAMICS ON AGRICULTURAL TERRAINS

Abstract

For tractor operation on deformable terrains, accurate terrain profiles are critically needed to determine the dynamic tractor response, which is affected by the terrain roughness. Effective profiles for tractors operating on agricultural terrains were identified in this study. A novel technique, called independent component analysis (ICA), was used to estimate the effective profiles. ICA can use a known system dynamic response (observed signals) to identify road-induced excitation. In this context, tractor wheel vibration signals were used as observed signals, and the ICA method was used to estimate the source signals, which are the effective profiles of the terrain. The proposed approach was validated by comparing the estimated profiles with those measured by a profiling apparatus in the time and frequency domains. The calculated root mean square error RMSE and the relative error Ef between the measured and estimated profiles showed that the proposed approach can be used to accurately estimate road profiles. A group of grass-field roughness data was taken as an example to compare the characteristics of the original and effective profiles, and the parameters of the effective profiles, such as the RMS, roughness index C and waviness W were found to noticeably change during the interaction between the tractor wheel and the terrain soil.