Longitudinal and lateral differential braking decoupler for enhanced aircraft ground handling

Differential braking is one of the fundamental mechanisms to generate the required yaw moments for adequate directional control during aircraft ground handling. Current design practices in aircraft braking systems favor two independent braking channels at each side of the main landing gear, each connected to a cockpit pedal. The map between the pedal deflection and commanded braking pressure is a key design parameter that is often difficult to calibrate. In this paper, we analyze the impact of conventional piecewise linear pedal laws on the differential braking dynamics, revealing discontinuous sensitivity variations that interfere with adequate directional control. We show that such sensitivity variations can lead to limit cycles in simple ground handling tasks. Moreover, we propose a novel differential braking decoupling architecture that can mitigate the sensitivity variations and enhance directional stability. The decoupler is highly customizable and can accommodate different design goals in the directional and longitudinal ground handling dynamics. We validate the results with real-time pilot-in-the-loop experiments of centerline tracking and centerline capture maneuvers conducted with a highly accurate multibody nonlinear aircraft simulator. We show that the proposed decoupler enhances directional control and reduces pilot workload against the independent braking structure.