Аннотация:Our goal is to build up an efficient computer model of the omni-vehicle comprising several omni-wheels (each one carries several freely rotating rollers on its periphery); the vehicle rolls without control on a horizontal plane. For simulating contact interaction we use the holonomic non-ideal constraints instead of ideal non-holonomic ones. Although there exist papers on the dynamical models of the vehicle and its control, e. g. [1, 2], here we study how the algorithm for computing the contact forces between a particular roller and the plane influences a description of the vehicle dynamics. To simulate dynamics we build up our dynamical models using Modelica language of object-oriented modeling. Earlier we proposed the contact tracking algorithms [3] for the point-contact dry friction regularized by linear saturation function. Using numerical simulations of the models developed we compare the vehicle dynamics for three particular contact models: (a) ideal non-holonomic contact “with impacts”, (b) model of viscous friction with the large coefficient of viscosity, and (c) one with the regularized dry friction concentrating mostly on the tangent forces description.