Prediction of pilot induced oscillations

Abstract

An important problem in the design of flight-control systems for aircraft under piloted control is the determination of handling qualities and pilot-induced oscillations (PIO) tendencies when significant nonlinearities exist in the vehicle description. The paper presents a method to detect possible pilot-induced oscillations of Category II (with rate and position limiting), a phenomenon usually due to a misadaptation between the pilot and the aircraft response during some tasks in which tight closed loop control of the aircraft is required from the pilot. For the analysis of Pilot in the Loop Oscillations an approach, based on robust stability analysis of a system subject to uncertain parameters, is proposed. In this analysis the nonlinear elements are substituted by linear uncertain parameters. This approach assumes that PIO are characterized by a limit cycle behavior.