INTEGRATED DETERMINATION OF TRACTOR CENTRE OF GRAVITY AND LATERAL ROLLOVER ANGLE

Tractor roll-over is one of the major safety issues particularly when these machines operate in mountainous environments. This causes nearly 140 fatal accidents each year in Italy, and many other cases still result in considerable vehicle damages and loss of income from lost work. Therefore, the development and implementation of stability models to study the behaviour of existing vehicles operating in hazardous conditions results very important, especially if they are originally designed to work on flat surfaces. From them, new solutions can be integrated into the vehicles control systems to warning the operator when an instability is approaching, or to implement automatic countermeasures to prevent it. However, the validation of these models is still a challenge as they must be compared and calibrated with experiments on real machines (i.e., too much complexity in working with bulky and heavy machines even from a safety point of view). In this work a four-wheel-drive narrow-track tractor (New Holland TN75V) is considered as a test case. Firstly, a mathematical model of static rollover stability was derived to predict all instabilities for any orientation of the machine. The results are then compared with an experimental test campaign performed on a real tractor and taking advantage of an innovative vehicle stability test rig available at the Agroforestry Innovations Lab (AFILAB) of the Free University of Bozen-Bolzano.