Abstract: Electromechanical integrated toroidal drive is a new-style generalized composite transmission in which mechanism, electronism and control are integrated. The dynamic characteristics of toroidal drive system are affected by nonlinear fluctuation of rota- tory inertia for the rotor during running obviously. In toroidal drive, manufacture error and installation error of multi-planets that are equably placed in space lead to periodic fluctuation of their gyration center and the rotor moment of inertia. Firstly, considering the fluctuation of rotatory inertia, the differential equation of toroidal drive system is expanded into the form of Mathieu equation by talor series expansion and chang-of-variable. And then, stabilities curves and stabilities figures of toroidal drive system with different excited frequencies are worked out by Linstedt-Poincare Perturbation method, and stabilities of toroidal drive system are discussed. Next, excited frequencies and amplitude of rotatory inertia for the rotor are analyzed in influence on stabilities of toroidal drive system. Finally, an example illustrates practical application of theories.

Key words: Electromechanical integration, Parameter excitation, Perturbation method, Stability, Toroidal drive