Lateral Directional Aircraft Control Using Eigenstructure Assignment

Abstract

Although recently overshadowed by various H1-based techniques in the research literature, eigenstructure techniques offer a simple method for designing low-order, easily implementable controllers that can directly incorporate handling quality specie cations. It is well known that, for a controllable linear system, eigenstructure techniques can be used to design a linear feedback controller that places closed-loop eigenvalues and shapes closed-loop eigenvectors into desired cone gurations. 4 The question for the designer is how to specify these desired eigenvalues and eigenvectors. The approachdevelopedinthisNoteistouseastate-spacemodelofdesired responses that is based on e ying quality specie cations. This statespace model is then used to generate the desired eigenvalues and eigenvectors, which are to be obtained by feedback control. In this Note, a direct method is used for calculating the gain matrix, which achieves the desired eigenvalues exactly and the desired eigenvectors in a best least squares sense. Direct methods for eigenstructure assignment by least squares methods are described in numerous references. 1i6 Garrard et al. 5 and Low and Garrard 6 showed how to use handling quality specie cations for helicopters to generate desired eigenstructures, which were then achieved in a least squares sense by feedback control.In this Note, the technique is extended to lateral-directional control of an aircraft. As an illustrative example, controlofa tailless aircraftisconsidered.The method of state-space modelingofhandlingqualitiescouldalsobeusedindesignofmodel matching H2 or H1 controllers.