Nonlinear dynamic analysis of electrically driven gear transmission system for battery electric vehicle

To investigate the nonlinear dynamic characteristics of an electrically driven gear transmission system in battery electric vehicles, a coupled nonlinear dynamic model incorporating bending, torsion, and axial vibrations was developed. This model integrates the motor’s external characteristic curve and accounts for factors such as time-varying mesh stiffness, mesh damping, and gear backlash. The model was solved to obtain the nonlinear dynamic response of the gear transmission system. Bifurcation diagrams and Lyapunov exponent diagrams were generated with respect to mesh frequency, time-varying mesh stiffness coefficient, damping ratio, and gear backlash. The system’s bifurcation characteristics were thoroughly analysed using time-domain diagrams, phase portraits, and Poincaré sections. A test platform was designed to conduct vibration experiments, which validated the accuracy of the developed dynamic model. The results indicate that variations in mesh frequency induce rich dynamic behaviours, primarily alternating between periodic and chaotic motion states. Within a certain range, the time-varying mesh stiffness coefficient can drive the system towards chaotic behaviour. Appropriately increasing damping or reducing tooth backlash simplifies the system’s motion and enhances its stability. The findings presented in this paper provide a valuable reference for subsequent research on the nonlinear dynamics of electrically driven gear transmission systems.