The application of actuator performance limits to aeroservoelastic compensation

Abstract

An interaction between an aircraft's structural dynamics, unsteady aerodynamics and flight control system can have serious effects on the aircraft both in terms of structural integrity and rigid body stability. The effects of such an interaction, known as aeroservoelasticity, are poorly understood and as a result, very conservative flight control system design methods are used in order to achieve flight clearance. This paper demonstrates how the use of nonlinear actuation system models predicts a maximum boundary for the amplitude of the structural response as a result of the performance limits of the nonlinear actuation system. This envelope of maximum structural response can then be used to allow relaxation of the current design criteria for the structural mode filters. The procedure is demonstrated using a representative aircraft system model. Finally, the results of single input frequency response tests of a representative actuation system are presented in support of the earlier results.