Journal homepage: http://sjsutst.polsl.pl Article citation information: Sakno, O., Moysya, D.L. Kolesnikova, T. Dynamic stability of a model of a tractor-lorrytrailer combination.Summary. In this paper, we consider the mobility and stability of a model of a tractor-lorry-trailer combination, consisting of a two-axle tractor and a single-axle semi-trailer, and its possible stationary states with fixed steering. A feature of this research is the study of a non-linear mathematical model of a two-link tractorlorry-trailer combination. The set of steady-state conditions for the movement of the tractor-lorry-trailer combination model is determined on the basis of the developed mathematical model; it provides the necessary mobility for the passage of the circular overall traffic lane. The range of stable steady-state conditions of the road train is limited and the character of the loss of stability in the direct motion of the road train (divergent, flutter) is checked. The phase portraits of the system are constructed at different speeds, which allow us to estimate the range of attraction for direct motion. Stability issues are also considered, namely, the influence of the control parameters (θ, v) on stability or instability.