Resumo:
Pilot-induced oscillations, subclass of aircraft pilot couplings (APC), are characterized by interactions between the pilot and an aircraft, which when unstable, result in sustained and/or uncontrollable oscillations from the pilot’s efforts to maintain control of the aircraft. In the pres-ence of non-linearities, such as rate saturation, the events tend to be severe and abrupt, subjecting the pilot to unfavorable conditions, being a contributing factor to PIO – and from what is known, in the loss of control in-flight (LOC-I). In this dissertation, we seek to evaluate the oscillatory tendency of aircraft with the purpose of mitigating PIO due to actuator rate saturation. The open loop onset point (OLOP) criterion was applied with this objective, given a pilot-vehicle system (PVS), including the control laws, pilot model, actuator rate saturation and aircraft dynamics. Then, as an innovation proposal, a robust controller based on conditional integrator sliding mode control (CISMC), was implemented. The results are presented in the subsequent simulations and analyses, with the intention of validating and comparing the responses obtained for the controller with models published in the literature. In general, the performance of the CISCM, for the cases analyzed, was satisfactory, with regard to the aircraft control and stability, with a decrease in the degradation of responses and phase delays, showing a positive indication in reducing the risks of PIO occurring, in order to develop countermeasures and strategies that ensure aircraft flying qualities.
