Adaptive control for aircraft anti-skid braking system based on friction force model

The improvements of aircraft braking system reliability and efficiency are important for the safety promotion of a whole flight circle. The aircraft tire/runway friction force varies significantly on different types of runways (dry and wet, etc.), materials (asphalt and soft ground, etc.) and temperatures. This affects the braking control efficiency and even the effectiveness. The velocity correlative dynamic LuGre friction force model was introduced to describe the friction force, which could give a projective mapping from the physical unknown runway state to mathematical model with parametric uncertainties, and then the runny state could be detected through parameter estimations. Firstly, the fuselage and aircraft wheel were modeled and the state observers were employed to estimate the unmeasurable internal friction states of the friction force model. The estimates were substituted into the parameter adaptive law to obtain the current runny state. Then the online calculation of pseudo-static friction force model was applied to obtain the maximum friction coefficient and its slip rate. This slip rate was set as the tracking target for the well-designed feed-forward controller based on the feedback linearization method. At last, the simulation results were shown to prove the control effects.