Dynamic Characterization of a Two Degree of Freedom Planetary Gearbox During Varying Load Conditions

This paper presents the dynamic characterization of a two degree of freedom planetary gearbox prototype during the variation of the load condition. Tests with varying load are developed at three different operating speeds of the input shaft: 190, 380 and 590 rpm. The dynamic torques and vibrations on the input and output shafts are acquired during the experiments, such as the angular velocity of the output shaft. The experimental data are analyzed to evaluate the dynamics of the system during the exchange of operation between the first and second DOF operation. Then, the radial vibrations are analyzed during the operation of the second DOF by means of a methodology using different signal processing tools: first, the continuous wavelet transform is used to identify the nonlinear behavior and the main frequency content of the system; then, the vibrations are filtered by means of passband filters in order to keep the main frequencies of the system and delete any other; finally, the filtered signals are analyzed with both, the Kuramoto’s order parameter to quantify the dynamic synchronization of the gearbox and the phase diagram to characterize its stability. The results demonstrates the utility of the second DOF in the design of the planetary gearbox in order to avoid excessive torques in the components of the system. Furthermore, it is found that the synchronization of the system increases at higher operating speed, however, the system becomes unstable as the operating speed is increased.