The equation of motion for a mechanical system with a variator

Kukhtenko, 1955, On one class of mechanisms with non-holonomic constraints, Trans. Inst. Study Machines (Sem. Theory Mach. Mech.), XV Lur'ye, 1961, Analytical Mechanics Umnov, 1967, A Graphical Method of Solving Dynamical Problems of Mechanisms with Variators, Mashinovedenie Roskoshnii, 1963, A Complex Calculation of Mechanisms with Continuous Variation of the Transmission Ratio, Transmission Gears