Time-optimal control for advanced aircraft in the presence of uncertainties

Control configurations significantly influence the aircraft performance. A new synthesis method, which enables the integration of the constrained optimization methodology to uncertain aircraft dynamics, is presented. This paper deals with minimum-time control issues for vehicles subjected to parameter variations and constrained stare variables. Advances in computer technology have stimulated real-time flight control based upon the use of on-line optimization. Although optimal theory is well developed, the calculus of variations and Pontryagin's principle are not well suited for high-order aircraft models with uncertain parameters. These methods are hampered by the limited amount of time available for computations. This paper discusses the minimum-time flight control problem and presents a new synthesis procedure to ensure the robustness and time-optimal dynamics for aircraft with constraints and uncertainties. Utilizing the dynamic programming principle, the procedure provides a straightforward avenue for the design of robust bang-bang control structures. A nonquadratic performance measure is used. We present theoretical results showing that the robustness is guaranteed. Other advantages of this technique are feasibility and computational efficiency. This scheme allows us to solve on-line the constrained optimization problem for advanced vehicles.