The paper presents a certain method of analysing the dynamics of a belt transmission. A flat transmission model developed by us was presented. For the analysis, it assumed the transmission 5PK belt. A discrete belt model, being a system of rigid beams interconnected with flexible and shock-absorbing elements, was used. To account for the mutual influence between the belt and pulleys, the Kelvin–Voigt contact model was used. The GMS friction model was also implemented, which allows all basic known friction phenomena to be taken into account. For this purpose, the vector of generalized coordinates was expanded with additional sub-systems of coordinates modelling the flexible belt-pulley connection. Moreover, two additional cases of a sudden transmission start were presented: with values of driving and resistance torque not causing a significant slip in the transmission as well as values of torque that cause slip.
<p>The slender structures of a medical robot may have a tendency to buckling when a force equal to the critical Euler force and an additional disturbance will work on their structures. In this work, eigenvalue problem that describes the linear buckling, is under consideration. The main goal of the article is to check when linear buckling phenomenon appears in construction of a medical robot with serial chain due to the fact that for safety reasons of a robot’s work, it is necessary to answer the question, whether the buckling may occur in the robot’s structure. For this purpose, a numerical calculation model was defined by using the finite element method. The values of load factor coefficients that are eigenvalue are determinated and also the eigenvectors that have shapes of deformation for the next eigenvalues are presented. The multi-criteria optimization model was determined to aim for the minimum mass of the effector and the buckling coefficient, from which the Euler force results, for the maximum. The solution was obtained on the basis of Pareto fronts and the MOGA genetic algorithm.</p>
Two algorithms which allow one to take an uneven road surface into account in the vehicle dynamics analysis are presented in the article. Their essence is to determine the position of the contact point of the tire model with the uneven road surface. According to the concept of the authors, the names of the algorithms are to refer to the essence of the matter of the procedures assumed. The first of them -named Plane -can be used while considering the continuous model of the surface obtained by use of "the bicubic interpolation" taken from computer graphics, and the second one -named 4Points -in the case of the discrete model of this surface, developed especially for needs of the methods presented. In the work, it is assumed that only continuous changes of the road profile, without its possible abrupt changes, e.g. in form of a transversely placed threshold of sharp edges, can be considered. Therefore, the mapping of the road surface, obtained in the case of including its both models, is smooth. The developed algorithms are used to analyze dynamics of a technical rescue vehicle which can drive in terrain conditions.
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