Modal control of relaxed static stability aircraft

Abstract

A method is developed that assigns a selected portion of a closed loop system eigenstructure in accordance with certain desirable criteria. The method is applied here to a relaxed static stability aircraft, the goal being to synthesize a control law that provides the unstable aircraft with handling qualities equal to or better than those of a comparable statically stable aircraft. It is shown that by using the target system eigenstructure, good flight characteristics are achieved by the unstable aircraft. It is also shown that improved characteristics can be obtained by assigning an orthogonal eigenvector structure.