Fighter aircraft lateral axis full envelope control law design

Abstract

A decoupled wide envelope lateral/directional axes control design is presented for a supermaneuverable version of an F-18 aircraft. A control structure is developed that separates gain-scheduling issues from aircraft performance issues. Flightcondition dependent state and control effectiveness variations are accounted for by an inner loop controller designed using eigenstructure assignment. Structured singular value synthesis is used to design an implicit model following outer loop controller that addresses flying qualities performance specifications. A control selector is designed that generates lateral/directional aerodynamic and thrust vectoring commands from generalized control inputs of roll and yaw acceleration. Robustness analysis show that the control system performs well despite neglected dynamics and system uncertainties. Nonlinear simulations are presented showing excellent decoupling of roll and yaw responses.