Optimization and Systems Theory Seminar
Monday, June 16, 1997, 11.00-12.00, Room 3721, Lindstedtsvägen 25

Professor Shankar Sastry
University of California, Berkeley, CA

Hybrid control issues in air traffic management systems

The modeling and control of multi-agent, scarce resource systems requires both discrete protocols which coordinate the interplay among agents, and continuous control laws which regulate each individual agent. In a new research project at Berkeley, we are studying such systems in the context of Air Traffic Management Systems (ATMS). In ATMS, a large number of aircraft are required to converge from many directions to a few well defined airspace routes which lead to the airport runways.

The need for a new ATMS arises from the overcrowding of large urban airports and the need to more efficiently land and take off larger numbers of aircraft, without building new runways. In the current air traffic system, aircraft are routed and sequenced manually by a centralized, ground-based controller and the resulting system is fault intolerant and plagued by delays. Technological advances that make a more advanced air traffic management system a reality include the availability of relatively inexpensive and fast real time computers both on board the aircraft and in the control tower. We propose an architecture for an automated, decentralized ATMS, in which much of the control functionality exists in the flight vehicle management system on board each aircraft rather than at the ground-based air traffic control.

The complexity of this system suggests the need for a hierarchical control structure in which the high level discrete protocols control the relative positioning of the aircraft and the spacing between them, and the low level continuous control laws guide the aircraft along the given route. We discuss in this talk control strategies for both the discrete and continuous layers of the hierarchy. A game theoretic approach is used to generate a set of discrete protocols for the coordination among aircraft, as well as for control of the flight vehicle management systems of individual aircraft. The interface controllers between controllers built using different models is built using notions of ``consistent abstractions'' of hybrid control systems. Proofs of the safety and some measures of liveness and fairness of the control schemes will be discussed.

This is joint work with Claire Tomlin, George Pappas, John Lygeros, and Datta Godbole.

Calendar of seminars
Last update: June 2, 1997 by Anders Forsgren, andersf@math.kth.se.