Abstract
An important issue regarding safety in mountain agricultural and forestry operations concerns the machines rollover stability. Although new technologies and techniques have generally improved safe working conditions, there are still too many fatalities. This work focuses on the study and the comparison of the (static) rollover stability of three typologies of tractors commonly used in the Alpine environment: a conventional tractor, a narrow track tractor and a mountain specialist one. A mathematical model has been developed to predict the tractor stability behaviour in different machine orientations (i.e., not limited to the study of lateral stability alone) and scenarios, through the generation of stability maps. These are graphical tools that summarize the stability limit conditions for all the different configurations in a single representation. An important aspect of this work is that the model has been calibrated and then validated through a series of experimental tests on real machines. For this scope, a new rotating test-rig for evaluating the stability of vehicles (up to 10 tons) available at the Agroforestry Innovation Laboratory (AFI-Lab) of the Free University of Bolzano has been exploited. It consists in a rotating and tilting platform able to move a machine positioned on it in any direction, while measuring in real-time the wheels contact forces. The preliminary results, despite some simplifications adopted in the first version of the mathematical model, are very satisfactory, showing an excellent correlation.