Application of Pilot Induced Oscillations Prediction Criteria To Rotorcraft

This paper investigates the applicability of fixed-wing aircraft pilot induced oscillations criteria to rotorcraft. Three prediction criteria, among the several proposed in literature, were chosen for this study, namely the Bandwidth/Phase Delay method, the Open Loop Onset Point (OLOP) criterion and the Realtime Oscillation VERifier (ROVER). A pilot+rotorcraft mathematical model, developed in MATLAB®, was used to test the criteria. Pilot-in-the-loop simulations were carried out in a fixed-base simulator to verify the criteria's reliability. The global results obtained from the comparison of the PIOs criteria outcomes with the simulation tests data showed an acceptable correlation. The simulator tests provided useful information about the choice of the manoeuvres most suited to detect a rotorcraft's PIOs tendencies.