Adaptive Control for Aircraft Anti-Skid Braking System

The aircraft tire friction force varies significantly with different types of runway materials, surface lubricity and vertical load, which affects the braking efficiency. In this paper, the dynamic LuGre model is introduced to describe the friction force, which could give a projective mapping from the physical unknown runway state to mathematical friction force model with parametric uncertainties. The state observers are employed to estimate the unmeasurable internal friction states of the friction force model and the estimates are substituted into the parameter adaptive law to obtain the current runway state. The pseudo-static friction force model is calculated online to obtain the maximum friction coefficient and its slip ratio. This slip ratio is set as the tracking target for the well-designed feed-forward controller based on the feedback linearization method. The simulation results are shown to verify the proposed method.