Technique for predicting longitudinal pilot-induced oscillations

A technique for predicting the susceptibility of an aircraft to longitudinal pilot-induced oscillations (PIOs) is proposed. The technique employs the optimal control model (OCM) of the human pilot formulated for pitch attitude command tracking tasks. The criterion is very simple and is based solely on the characteristics of the pilot/vehicle open-loop transfer function as predicted by the OCM. The criterion has its genesis in the results of a previous study using the OCM in pitch attitude tracking tasks and was evaluated here using results from flight tests of 25 configurations flown on the NT-33 variable stability aircraft and three additional configurations from flight tests of a high-performance aircraft. Only the index of performance weighting coefficients in the OCM are considered as model variables, and a technique for generating these coefficients is reviewed.