Macroscopic Fundamental Diagrams for Low-Altitude Air city Transport

Low-altitude aircraft is being developed as a new mode of urban transport; consequently, the penetration of low-altitude aircraft into the urban airspace is inevitable in the near future. This will give rise to new urban air transport systems, called low-altitude air city transport (LAAT) systems. Such systems will include aircraft operated with or without pilots, transferring passengers and goods in urban areas using low-altitude levels of urban airspace. This paper investigates the collective and aggregate aircraft traffic flow diagrams, i.e. Macroscopic Fundamental Diagrams (MFDs), for LAAT systems. A LAAT plant model that captures the microscopic and macroscopic levels is established to construct the MFD curve, which links flow, density, and speed. The MFD allows us to identify the airspace traffic conditions, and to detect congested regimes. Different case study examples were simulated to analyze the full shape of MFD curves for LAAT systems, considering different algorithms (waypoints and destination plane), aircraft, and airspace settings. In this paper, a unique modeling framework for LAAT operation and a real-time synchronized implementation of large-scale LAAT simulation were developed. The findings of the current paper, the development of LAAT simulation environment, and the identification of airspace traffic conditions, can lead to the development of aggregate models and new control strategies to minimize congestion in futuristic urban airspace.