行星齿轮传动系统在润滑不良等极端工况下运行时，容易发生齿面点蚀故障，严重影响传动精度与服役寿命。为保障系统可靠运行，需深入探究点蚀故障下的系统动态特性。本文综合考虑点蚀故障状态下的时变啮合刚度、时变摩擦力、传动误差和齿侧间隙等因素，建立一种多重激励因素耦合的行星齿轮传动系统非线性动力学模型。采用四阶龙格-库塔数值积分方法对系统振动微分方程进行求解，通过时域图、相平面图、频谱图、小波时频图、三维频谱图及分岔图等表征方法，对不同转速与点蚀故障下的系统振动特性进行分析。结果表明：系统在不同转速下呈现出丰富的非线性动力学行为，包括周期运动、多周期运动及混沌运动等运动特征。轮齿点蚀故障通过改变时变啮合刚度，导致系统振动位移突变，降低系统稳定性。随着转速的增加，点蚀故障所引起的系统振动的振幅也随之增大。通过搭建行星齿轮传动系统动力学特性试验台，验证所建模型及计算方法的准确性。本文揭示点蚀故障与系统动态特性之间的内在关联，为行星齿轮传动系统的故障诊断与状态监测提供重要参考。

When the planetary gear transmission system operates under extreme conditions such as poor lubrication, it is prone to tooth surface pitting faults, which seriously affects the transmission accuracy and service life. In order to ensure the reliable operation of the system, it is necessary to deeply explore the dynamic characteristics of the system under pitting failure. In this paper, a nonlinear dynamic model of planetary gear transmission system coupled with multiple excitation factors is established by considering the time-varying meshing stiffness, time-varying friction, transmission error and backlash under the condition of pitting fault. The fourth-order Runge-Kutta numerical integration method is used to solve the vibration differential equation of the system. The vibration characteristics of the system under different rotational speeds and pitting faults are analyzed by time domain diagram, phase plane diagram, spectrum diagram, wavelet time-frequency diagram, three-dimensional spectrum diagram and bifurcation diagram. The results show that the system exhibits rich nonlinear dynamic behaviors at different rotational speeds, including periodic motion, multi-periodic motion and chaotic motion. The pitting fault of the gear tooth causes a sudden change in the vibration displacement of the system and reduces the stability of the system by changing the time-varying meshing stiffness. With the increase of the rotational speed, the amplitude of the system vibration caused by the pitting fault also increases. The accuracy of the model and calculation method is verified by building a dynamic characteristic test bench of planetary gear transmission system. This paper reveals the intrinsic relationship between pitting fault and system dynamic characteristics, and provides an important reference for fault diagnosis and condition monitoring of planetary gear transmission system.