Data Gathering and Preliminary Results of the System Identification of a Flexible Aircraft Model

Abstract

This paper presents the planning and preliminary results of a flight experiment aiming at the identification of an integrated model for the flight dynamics of a flexible aircraft in time domain. The experimental setup is explained in details, focusing on the choice of the appropriate flight test instrumentation and maneuvers. In addition to the usual measurements for flight dynamics identification, an arrangement of accelerometers and strain gauges was mounted on the aircraft structure, in order to provide additional information about the flexible states. Classical maneuvers for system identification are used to excite the rigid-body and aeroelastic modes. A flight test campaign was performed, using the high-performance glider SB 10 and examples of gathered time histories are presented to illustrate the flexibility effects on the aircraft response. Preliminary results of the identification of the longitudinal dynamics coupled with the first wing bending mode are presented, demonstrating the feasibility of using the system identification methodology in time domain to obtain a flexible aircraft model, accounting for the dynamic coupling between rigid-body and structural modes.