Validation of a Model-Based Structural Loads Monitoring System using the Flight Test Aircraft UW-9 Sprint

摘要

Operational loads monitoring is of increasing importance in the context of aircraft efficiency enhancement. It allows for a detailed knowledge of structural loading due to flight maneuvers and gusts and provides the opportunity to improve structural inspections and maintenance procedures. At the Hamburg University of Technology, model-based methods for structural loads monitoring are investigated. One promising approach is the so-called Loads Observer. It mainly consists of a nonlinear aircraft model. In order to provide the component loads as a result of pilot inputs and due to turbulence and gusts, the aircraft model is part of a nonlinear Luenberger observer. The observer enables an estimation of the unknown disturbances, which are used as an additional aircraft model input. In this way the estimation of turbulence related component loads becomes feasible. The present paper illustrates the Loads Observer implementation and validation for the flight test aircraft UW-9 Sprint. The development of the Loads Observer model structure and the identification of included parameters using the output error method are outlined. Finally, the estimated loads are compared to measured loads. For that purpose, a comprehensive flight test database containing relevant maneuver and gust loads is used.