Friction-Induced Vibration Analysis of an Aircraft Electric Braking System Considering the Transmission Mechanism

Friction-induced unstable vibration caused by nonlinear stator–rotor friction and electromechanical coupling is a critical dynamic stability issue in aircraft electric braking systems, potentially degrading braking performance and operational safety. In this study, a novel nonlinear dynamic model of an aircraft electric braking system is developed by considering nonlinear stator–rotor friction, the nonlinear meshing force of the gear pair, and the nonlinear axial contact stiffness of the ball screw pair. The effects of braking conditions, negative friction–velocity slope, and transmission mechanism parameters on the stability and global nonlinear dynamic behavior of the system are systematically investigated. The results indicate that the negative friction–velocity slope has a critical influence on system stability. Reducing its magnitude simplifies the steady-state response and improves system stability, while the corresponding instability boundary depends on the braking conditions and system parameters. In addition, increasing the screw lead reduces the vibration intensity and simplifies the vibration modes of the system. The time-varying meshing stiffness and backlash of the transmission mechanism significantly affect the impact response and vibration intensity of the transmission mechanism, but have little influence on the vibration response of the disc brake. These findings provide theoretical guidance for vibration suppression, stability-oriented design, and parameter optimization of aircraft electric braking systems.