Observation of load transfer from fully mounted plough to tractor wheels by analysis of three point hitch forces during ploughing

During in-furrow ploughing the wheel running in the furrow exposes the soil to greater risk of undesired compaction of the subsoil. This fact is due to a different load placed on the rear axle wheels of the tractor. The wheel moving in the furrow is loaded more than the wheel moving on the land. This fact is also reflected in fuel consumption and performance. The aim of this paper was to analyse the possibility of eliminating the problem with different loads of the rear wheels by changing the length of the upper link of the three-point hitch. We also studied the impact of adjustments made on the economics of ploughing. During the experimental ploughing carried out for three lengths of the upper link, we have indirectly evaluated the load on the wheels. In the course of ploughing the exerted forces were measured by the strain gauge sensors attached to each link of the three-point hitch. These measured forces we used to calculate the load on individual tractor wheels using a verified algorithm that uses a multibody tractor model. The results show that the large difference between the loads on the left and right rear wheels typical for in furrow ploughing can be reduced by adjusting the length of the upper link of three-point hitch from the original 5 kN-1 kN. Changing the wheel load resulted in reduction of fuel consumption per ploughed area by 13.7% and increased performance, namely the area ploughed per unit time, by 6.45%.