31th Congress of the International Council of the Aeronautical Sciences

06.1 - Flight Dynamics and Control (Control & Modelling)

CLOSED-LOOP SYSTEM IDENTIFICATION OF A LARGE FLEXIBLE AIRCRAFT USING SUBSPACE METHODS

R.C.M.G. Barbosa╣, L.C.S. Gˇes╣; ╣ITA, Brazil

The aim of this work is present a methodology to identify flexible aircraft operating in closed-loop. The development of an accuracy model to flexible aircraft have been pursued because the coupling between rigid and flexible dynamics causes stronger interaction between flight control system and the structural modes. Preliminary results about the identification of a large elastic airplane known as Rockwell B1 is described. A priori, synthetic data of linear longitudinal dynamic considering two symmetric flexible modes are used as input to DSR (combined deterministic and stochastic system identification and realization) method. This algorithm is a subspace identification method that works to deals with closed-loop data. Later, the subspace method will be applied to synthetic data considering the completed nonlinear model including three symmetric modes. The preliminary results suggest a representative model for aircraft even returning only the state-space matrices, which can be evaluated by some control system law design.rn


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