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DINAME 2023
XIX International Symposium on Dynamic Problems of Mechanics
Practical application of Open Loop Onset Point Criterion to predict actuator rate saturation PIO in fly-by-wire aircraft
Submission Author:
Juliano A. B. Gripp , SP
Co-Authors:
Juliano A. B. Gripp, Marco Aurélio Guimarães Moreira, Luis Gonzaga Trabasso, Cleverson Marinho
Presenter: Juliano A. B. Gripp
doi://10.26678/ABCM.DINAME2023.DIN2023-0108
Abstract
Actuator rate saturation has been a contributing factor for Pilot-Induced Oscillations (PIO) experienced on some aircraft incidents, indicating potential design problems of flight control laws. Some criteria to predict this kind of phenomenon during design has been proposed in last decades, such as the Open Loop Onset Point (OLOP) criterion. In order to explore the capacities of prediction and limitations of OLOP criterion applied to the design of representative flight control laws for a transport aircraft in full flight envelope, two methods of control laws to regulate roll rate and sideslip (“p-beta”) were evaluated. As first method, consider a dead zone for roll spoilers, such that roll spoilers deflect only after certain deflection of ailerons. As second method, consider that ailerons and roll spoilers work together whenever required. OLOP criterion was applied in both methods with maneuvers varying pilot gain, frequency, and amplitude. These combinations were compared in practical offline simulations. Results show that OLOP criterion can be adopted as a first filter to identify potential PIO scenarios, although it presents difficulties for setup. Benefits and limitations of OLOP application are highlighted.
Keywords
nonlinear dynamics, rate saturation, open loop onset point, fly-by-wire aircraft, control law
