Anti-Skid Induced Aircraft Landing Gear Instability

The paper deals with the application of multidisciplinary multibody modelling to the analysis of a particular aircraft landing gear-induced instability, known as “gear walk”. This low frequency fore-and-aft oscillation of the landing gear (LG) is primarily due to the coupling of the LG deflection with the brake anti-skid control system characteristics. The objective is the development of a modelling approach that can be used as a design tool for the anti-skid controller in order to avoid malfunction during the braking manoeuvre. A comprehensive multibody model of an aircraft with a tripod main LG is developed and used, together with a simple anti-skid model, to predict the onset of the instability. The components used in the multibody model are thoroughly explained and the numerical results obtained are presented and discussed.