Research on optimal reference point selection method for path tracking of articulated tractors based on whole vehicle dynamic deviation control

With the development of smart agriculture, articulated tractors are increasingly applied in hilly and mountainous areas, where precise path tracking under lateral slippage remains a major challenge. Due to the articulated structure, the front and rear vehicle bodies exhibit different responses to terrain disturbances, making conventional single-point reference tracking insufficient for accurately describing whole-vehicle deviation. To address this issue, this study proposes a novel multi-point tracking deviation index that integrates the deviations of the front axle center, articulation point, and rear axle center. Based on this index, a systematic comparison of different reference points, including the centroid, incenter, and circumcenter of the characteristic triangle, is conducted through co-simulation experiments. The results demonstrate that the centroid yields the smallest whole-vehicle comprehensive deviation, achieving average deviations of 0.040 and 0.037 m under U-shaped and closed-curve paths, respectively, corresponding to reductions of 87% and 88% compared with the traditional articulation-point-based method. These findings indicate that the centroid provides the most balanced and robust reference point for articulated tractor path tracking under terrain-induced slippage, offering an effective trade-off between tracking accuracy and computational efficiency for autonomous operations in complex agricultural environments.