A Historical and Prospective Look at Aerodynamic Modeling and System Identification from Flight Data

Abstract

System identification is fundamental to any observed dynamic process. This overview presentation brings out why and what system identification is as applied to flight vehicles. A historical background is briefly provided, tracing the developments to the 18th Century and early flight experiments to 1920s. This is followed by highlighting the unified Quad-M approach to flight vehicle system identification that has evolved over the last three decades. Several examples are presented, covering: 1) generation of complete aerodynamic databases, 2) estimation of nonlinear models for control surface effectiveness and stall hysteresis, 3) aerodynamic effects due to landing gear, and 4) Air drop. Some aspects of model validation are brought out. Finally, diversified applications to other flight vehicles are briefly elaborated to demonstrate the wide domain of applicability. The talk is concluded by indicating the possible future directions of work.