Abstract. Mechanical transient processes in single-engine and two-engine three-mass mechanisms of executive axes of servo drives of support-rotating systems are considered. Vector – matrix mathematical models describing the processes are proposed. Formulas for calculation of resonance frequencies are presented, the model data are confirmed by results of spectral analysis of the transient processes carried out with the use of MatLab package. Transformation of initial models with the use of electric analogy method allows calculating parameters of equivalent two-mass models of two-engine servo drives with three-mass mechanisms of the axes. The results provide a basis for selection of structure design and development of rigorous method for synthesis of control systems of telescope servo drives with two-engine three-mass mechanisms of the axes.

Keywords: executive axis, three-mass mechanism, mathematical model, mechanical transient processes, resonance frequencies, spectral analysis