Close-loop stabilization of a flexible wing aircraft

The design of the airframe of an aircraft is constrained due to aeroelastic effects (generally related to the wings) that induce flexible modes on the structure, and may lead to structural instability. This paper addresses the problem of active mode stabilization in an aircraft with flexible wings. The main objective of closed-loop control is to enlarge the allowable flight envelope by stabilizing flexible modes that become unstable after a certain airspeed is exceeded. The nominal full-order (FO) model has a very large state dimension and hence the controller is designed using a reduced order (RO) model. This paper offers an analysis of the trade-offs present when designing controllers for systems under the premise of large order model reductions. Simulation results are provided using a reliable high order linear model.