A negative imaginary solution to an aircraft platooning problem

Over the next decade, the growth of commercial aircraft is expected to increase by 30%, causing significant challenges in air traffic management and control. To address this problem, we propose the idea of aircraft platooning during the descending and pre-landing phases. The objective is to design a distributed flight guidance and control system that assists onboard pilots in finding a feasible and collision-free trajectory from descent to pre-landing. The proposed aircraft platoon control scheme comprises a feedback linearising controller in the inner loop that transforms the nonlinear aircraft dynamics into a MIMO double-integrator, inherently a Negative Imaginary system. The outer loop employs a distributed output feedback Strictly Negative Imaginary controller, enabling networked aeroplanes to maintain the desired inter-aircraft spacing along each coordinate by synchronising their velocities. In addition, a contingency strategy is proposed to handle potential runway failures (e.g. sudden blockage, damage, etc.) by switching a descending aircraft platoon into a time-varying hover formation for each aircraft, maintaining a safe vertical gap. Finally, a comprehensive MATLAB simulation case study is conducted to test the feasibility and performance of the NI theory-based aircraft platoon control scheme.