高支柱起落架走步振动与稳定性分析

In order to improve the gear walk instability of high strut landing gear equipped with carbon ceramic brake discs, the rule of gear walk is analyzed thoroughly. The gear walk mechanism is explained. The braking torque with negative slope caused by the friction characteristics of the carbon ceramic brake disc can introduce negative damping to the longitudinal system of the landing gear, which causes the divergence of walking vibration. The effects of the brake torque parameters, the structural parameters of landing gear and the initial velocity of aircraft on gear walk are studied. Finally, a gear walk control strategy for reducing the braking pressure with the relative angular velocity of brake stators and rotors is proposed. The result shows that the decrease in the absolute value of negative slope of brake disc friction coefficient and the braking pressure, as well as the increase in the longitudinal stiffness and damping of strut will all contribute to the stability of gear walk. The stable gear walk can be achieved at any initial velocity of aircraft by increasing the minimum friction coefficient of brake disc to 0. 186. The dropping slope of braking pressure is closely related to the initial velocity of aircraft. The simulated results of aircraft braking from 144 km / h show that a 24. 7% dropping in braking pressure can lead to the convergence of unstable gear walk and a 77. 23% reduction in the longitudinal acceleration peak of wheel axle.