Application of modern mathematical apparatus for determining the dynamic properties of vehicles

Purpose. Study of hydraulic-mechanical transmissions in the process of braking a mining diesel locomotive and determining their efficiency. Methodology. The paper uses the technique of matrix analysis of transmissions by Prof. V.B. Samorodov, based on the division of the kinematic scheme into structural elements. The method was chosen as the basic method due to its universality and the possibility of implementation with the help of computer technology. The developed mathematical models of the vehicle braking process take into account the possibility of a smooth change (decrease and increase) of the transmission ratio and the torque applied to the executive bodies. Findings. The advantages and disadvantages of the use of hydromechanical stepless transmissions in the braking modes of the diesel locomotive are determined. It was mathematically proven that such transmissions are efficient, it is limited by methods of implementing braking. The results of the modelling allow to justify the braking control strategies of the locomotive equipped with a hydromechanical transmission. Originality. The technique of matrix mathematical modelling of transmissions that work as part of mining and transport machines has got further development. The developed mathematical model of the braking process of a mine diesel locomotive with HMT allowed to study the change in the kinematic and power parameters of the transmission in different operating conditions of diesel locomotives – movement on traction and transport ranges, on descent and ascent, at different initial braking speeds for all possible ways of implementing the process braking. The obtained results made it possible to substantiate the braking control strategies depending on the initial speed and traction power of the mining diesel locomotive. Practical value. The obtained results testify to the operational efficiency of the considered transmissions due to correctly selected strategies of braking control, which exclude the possibility of the occurrence of emergency modes of operation, failure, and reduction of the service life of the transmission elements. The practical value of the paper is confirmed by the social effect due to the improvement of labour safety in locomotive transport.