ROBUSTNESS ANALYSIS OF NONLINEAR FLIGHT CONTROL LAWS OVER CONTINUOUS REGIONS OF THE FLIGHT ENVELOPE

In this paper, a hybrid global/local optimisation algorithm is developed and applied to the problem of analysing the robustness of a nonlinear flight control law over continuous regions of the flight envelope. The analysis employs a typical nonlinear clearance criterion used by the European aerospace industry together with a simulation model of a high performance aircraft with a full authority control law which is gain scheduled over the flight envelope. The flexibility of global optimisation methods is exploited to allow for clearance of the flight control law over continuous regions of the flight envelope in the presence of multiple continuous variations in key aircraft parameters. Convergence properties of the optimisation algorithm are improved by incorporating local gradient-based optimisation via a hybrid switching scheme.