Modeling and Simulation of Shaft Drive CVT: Study on Characteristic of Ratio Change Mechanism

This paper deals with a modeling and a control technique for a ratio change mechanism of the shaft drive CVT. The ratio change mechanism is composed of a geared motor, spur gears and ball screws. The natural frequencies are calculated by using a 6-degree of freedom model of the mechanism. The principal natural frequency depends on a torsional stiffness of the output shaft of the geared motor. This ratio change mechanism is controlled by a velocity control loop using the PI action as a dynamical compensator. The interaction between the principal natural frequency and the proportional gain of the PI action is investigated. Further, the performance of this mechanism is also investigated by simulations on time responses. Simulations show satisfactory results