Control and Robustness Analysis for a High-Infinity Maneuverable Thrust-Vectoring Aircraft

摘要

This study focuses on designing a nonlinear controller for high-u0001 maneuvers of a fighter aircraft with a thrust-nvectoring control ability and checking the robustness of the designed controller using the structured singular-valuenu0002-based robustness analysis. The controller is designed using the nonlinear dynamic inversionmethod. It is designednto engage either the aerodynamic control surfaces or the thrust-vectoring control paddles of the engines, dependingnon the flight conditions. The necessary mathematical models are built to describe the nonlinear flight dynamics, thennonlinear aerodynamics, the engine with thrust-vectoring paddles, and the aircraft sensors. The robustness analysisnis especially needed when thrust-vectoring control is engaged in a challenging high-u0001maneuver. This is necessary tonanalyze the effect of increasing uncertainty in the aerodynamic parameters in such a flight condition. In a flight withnthrust-vectoring control, the effect of the aerodynamic uncertainties on the robustness is investigated for twondifferent cases. In the first case, the aerodynamic forces andmoments are treated as if they are completely unknown.nThis unusual uncertainty assumption is proposed and investigated for the first time in this paper. In the second case,nthe aerodynamic forces and moments are assumed to be known but only with a limited degree of confidence (e.g.,n70%). The results of the robustness analysis for each case show that it is impossible to achieve a satisfactorynrobustness if the aerodynamic forces and moments are treated as completely unknown disturbances, whereasnrobustness can be achieved rather easily if they are known evenwith only 70%confidence.These conclusions are alsonverified with numerical flight simulations.