Study on Nonlinear Dynamics of RV Transmission System Used in Robot Joints

The nonlinear dynamic characteristics of RV transmission device was investigated according to dynamics theory, mass centralized method was used to establish the nonlinear dynamical model of RV transmission device, which was composed of inertial component, elastic element and damping element. The influence of the nonlinear factors as meshing stiffness varying with time (though the variation in the number of meshing teeth), backlash of gear pairs and errors were considered. Movement differential equations of system were derived, and these equations were changed to non-dimension, which were solved by Runge-Kutta method. Influences of excitation frequency and damping on system dynamic characteristics were analyzed. As the excitation frequency increased, the system would vibrate from single periodic motion to harmonic motion, chaotic motion. Along with the reduced damping, chaos vibration occurs gradually after a doubling periodic of bifurcation, as the system gradually gets into the chaotic state. The impact is also changed from coexistence of non-impact and the unilateral impact to coexistence of the non-impact, unilateral impact and bilateral impact.