Open-Loop/Closed-Loop Control Simulation on the Stability of a Landing Gear Undergoing Overrun Braking

Abstract

The antiskid braking system (ABS) of a landing gear of aircraft is one of the operating system which can guarantee an aircraft to taxi along the runway in safety. The ABS consists of wheel-speed sensor, antiskid braking controller and brake. As the output of ABS, the braking moment will directly influence both the braking efficiency and the taxiing stability of aircraft. The existing experimental results show that during the taxiing and braking operations of aircraft along the runway, overrun braking will not only make the wheel lock, tyre wear seriously, but also result in a marked drop in the taxiing stability of aircraft. For this reason, based on the viewpoint of the mechanical principle combined with the nonlinear control theory, we develop the open-loop/closed-loop control simulation on the dynamic properties and the taxiing stability of landing gear by numerical integral method. In this paper, we demonstrate and analyze the slipping phase-plane trajectories of a wheel and tyre under braking. In order for ABS to promote the braking efficiency and guarantee antiskid automatically, we present the variable structural control of braking moment and express the analytical conditions that the braking moment should be satisfied. Through dynamic simulations, we discuss the dynamic properties of main landing gear under taxiing and braking along the runway.