Optimization-Based Feedforward Controller Design To Minimize The Effects Of Cross-Coupling Of A Helicopter With Articulated-Rotor

Abstract

In this study, TAI T-625 GÖKBEY helicopter pitch, roll and yaw axis cross coupling effects due to collective command and pitch axis cross coupling effects due to pedal command are minimized. A practical method, frequency domain magnitude curve minimization, is applied in frequency range of interest which is 0.3-20 rad/s. Mathematical model created by the flight mechanics team is used as the reference model to obtain off-axis response magnitude curves. A cost function, which defines difference between coupled and decoupled curves quantitatively, is used for minimization objective. The resultant controller is implemented to the helicop-ter. Flight tests are conducted to obtain time domain and frequency domain comparisons. In time domain comparisons, magnitudes of the responses are compared to verify decrement. For frequency domain compar-isons, CIFER tool is used and magnitude curves are compared to verify suppression in frequency range of interest and the results are found satisfactory.