Dynamic analysis of nose landing gear shimmy considering hydraulic damping characteristics

Large and medium-sized aircraft widely employ nose wheel hydraulic steering systems to achieve steering control and shimmy suppression. The damping characteristic of the steering system is the core factor for effective shimmy control of the nose landing gear, directly influencing its dynamic performance. In order to investigate the influence of the hydraulic characteristics of the steering system on the shimmy behavior of the nose landing gear, this paper establishes the hydraulic model of the nose wheel steering system and the dynamic shimmy model of the nose landing gear for a specific aircraft type. Through simulation analysis, the oil damping torque characteristics of the hydraulic system and its coupling with the Coulomb friction torque are discussed, and the time-frequency dynamic characteristics of the front wheel swing angle under the anti-swing state are further studied. The results indicate that: The hydraulic damping of the steering system exhibits significant nonlinear characteristics during shimmy suppression. Appropriately increasing the system's Coulomb friction torque can effectively compensate for the limitations arising from the nonlinearity of the hydraulic damping. This research provides valuable references for optimizing the damping parameter design of steering systems and offers important engineering guidance for improving ground taxiing stability.