Brake-Induced Landing Gear Walk Vibration Analysis and Suppression Method Research

Abstract

During aircraft braking, brake-induced frequent wheel slippage may cause coupling vibration between the antiskid brake system and landing gear. Brake-induced longitudinal coupled vibration is also known as “gear walk” vibration. Gear walk vibration not only reduces the structural life of the landing gear but also impairs the efficiency of the aircraft braking system. This paper focuses on the landing gear walk vibration mechanism and suppresses the method by modifying the antiskid brake control law. Firstly, a comprehensive multiwheel landing gear walk vibration model is developed. This model describes not only the longitudinal and vertically coupled vibration characteristics of the landing gear but also the dynamics of the aircraft braking system and the fuselage. Secondly, by simplifying the landing gear walk to the transverse vibration of a cantilever beam with a tip mass, the landing gear walk vibration mechanism is revealed in the frequency domain. Finally, a method to suppress landing gear walk vibration by modifying the pressure-bias-modulated (PBM) antiskid braking control law is proposed, which can solve the serious landing gear walk vibration problem caused by the conventional PBM control law. Simulation and experimental results show that the proposed method can suppress the landing gear walk vibration while improving braking efficiency.