Characterisation of the Behaviour of a High Power Tractor on the Road

In recent years the use of the tractor on the road has increased also due to a higher maximum velocity allowed. An increase in velocity has highlighted certain limits of the vehicle in terms of driveability and comfort. A lot of studies and standards on the behaviour on the road exist in the automotive sector. On the contrary, there are no studies on the tractor behaviour on the road but only off the road with the objective of developing steering systems that facilitate the driveability of the vehicle compared to similar on the road studies. The objective of this paper is to design tests that allow to characterise the functionality of the steering system and the tractor behaviour on the road. The tests were executed on two high power tractors. The tests were carried out using the standards of the automotive sector with some changes: a decrease of the travelling velocity, the lateral acceleration and the maximum frequency of the steering action. Different parameters characteristic of the steering system were analysed in function of the lateral acceleration of the tractor while steering to take a turn with a constant velocity and in function of the oscillating frequency of the steering wheel with a constant velocity. The results are a global behaviour of the tractor on the road and in particular the characterisation of the steering system’s quality.