A predictive model for the vibration risk evaluation in agricultural machinery use

Several well known national and international Standards provide different limits relevant to workers' vibration exposure. The agricultural activity is characterized by seasonal work peaks, in which operators widely exceed the traditional 8-hours work day, alternated to other long time periods of relatively light activity. On the other hand, agricultural machinery management involves many different tasks, in terms of procedures to be completed, considering the variety of operating conditions. As a consequence, the evaluation of the operator's vibration risk exposure is very difficult, and the results obtained are normally very poor, because they take into account the inputs from the vibration levels published on the machinery instruction manuals. On the basis of a suitable campaign of field trials, the present paper proposes the building of a predictive model for the vibration exposure, starting from the worldwide most popular agricultural machine, the tractor and one of the most frequently carried out operation, ploughing. This job represents a very effective example, as for its high frequency of execution, because ploughing is normally (both in-furrow and out-of-furrow) a very hazardous operation when considering vibrations point.