In this contribution, we present the description of a B-spline curve. We deal with creation of its basis function as well as with creation of the curve itself from entered control points. Following the literature, we formed an algorithm for B-spline modelling and we used it for the planar and spatial curve. The planar curve is made of chosen points. The spatial curve approximates the trajectory of a real vehicle, which trajectory was obtained by the set of measured points. The modelled curve very exactly describes the polygon created from the linked control points. With the lowering degree of the curve, this one is more clamping to the given polygon and for the extreme case it is transformed to the polygon itself. The advantage of the B-spline curve use is, for example in comparison with a Bézier curve, high adaptability, which is expressed in its parameters - besides entered control points, these are knots generated on the curve and degree of the curve.

In this contribution we present the methodology of the solution of ordinary differential equation by the Runge -Kutta numerical method of fourth order. Analysed function is continuous and it has derivatives at every point. Records of the centre of the gravity velocities of agricultural technological vehicle are function values of the derivatives. Algorithm of numerical integration was implemented by the help of programming language C# in MS Visual Studio Pro 2010 developing environment. Trajectory of the centre of the gravity movement in three-dimensional space is the result of the listed algorithm.

In this contribution, we deal with the methodology of visualisation of terrain surface, on which experimental measurements of driving manoeuvres of an agricultural technological vehicle MT8-222 were performed. The introduced methodology uses a defined approach when determining the dynamic stability of agricultural vehicles following the standard STN 47 017. Records of the centre of gravity accelerations were obtained from driving manoeuvres at every instance of time during the drive. From records of accelerations and by using Euler‘s parameters with respect to the inertial system, there were evaluated contact points of the wheel with the terrain. Performed driving manoeuvres consisted of movement in the direction of down grade slope as well as in the direction of tractive movement on the slope. We created a model of terrain surface in the Surfer® program from obtained experimental data. Next, by using supporting commands in Matlab®, we created an algorithm for visualisation of terrain surface. Following this algorithm, there was created another model of terrain surface. Both visualisations of terrain surface are depicted in Figs 4 and 5.