Whole Body Vibration Exposure during Rotary Soil Tillage Operation:

The Relative Importance of Tractor Velocity, Draft and Soil Tillage Depth

Abstract

The present investigation attempted to study the overall daily vibration exposure A(8) in actual field rotary tillage operation at various ride conditions (i.e. average velocity, draft and average soil tillage depth). Three different levels of each ride condition were chosen to formulate an organised design of experiments by using Taguchi’s approach. The concurrent root mean square (RMS) acceleration values were measured at the tractor platform, seat pan and seat backrest along the three translation axes to determine the A(8). Signal-to-noise ratios (SNRs) were computed and analysed concerning the conducted experiments. Further, the dominant frequencies at each set of experiment were determined by fast fourier transform (FFT) analysis. A linear regression model was developed to predict the output response and further, the ride conditions were optimised by using desirability approach. The overall daily vibration exposure was found between fairly uncomfortable to uncomfortable category (i.e. 0.64 and 0.84 m/s²) as per ISO 2631-1 (1997). Moreover, the exposure levels are beyond the exposure action limit recommended by Directive2002/44/EU. The average velocity and draft effects on the A(8) response were found significant (p≤0.05) with a contribution of 78.38% and 18.54%, respectively. The FFT analysis depicted a range of dominant peaks in the frequency range of 0.8 to 3.7 Hz. However, the exact frequency of the peaks was found to depend on the experimental condition. The prediction model indicates a good correlation between predicted and actual experimental response with an average error of 1.02%. Desirability and Taguchi’s approaches gave identical optimised ride conditions (i.e. 0.6 m/s, 6 kN, and 0.14 m) with the aim of reducing the A(8) value.