MULTIPLE INPUT MULTIPLE OUTPUT (MIMO) ANALYSIS PROCEDURES WITH APPLICATIONS TO FLIGHT DATA

Iterative algorithms for the solution of multiple input/multiple output (MIMO) problems, formulated from stationary flight test data, are developed here. These are direct extensions of Bendat's MISO algorithms. Computed are spectral, coherence, frequency response functions, both for the original and conditioned MIMO systems. A joint multiple coherence function is derived to describe the combined effects of both controls and states on any selected response. Additionally, output spectral decomposition is done to illustrate explicitly the effect of each of the controls and states. Specific MIMO applications studied from measured flight data of BO-105 helicopter are prediction of the effects of coupled controls and states on pitch rate response, and some lateral handling quality prediction of dutch roll and roll rotor flap modes.