Non Linear Aircraft Dynamics and PIO
Author: Philippe Montarnal
The purpose of this report is to study the Pilot Induced Oscillations (PIO) phenomenon.
The method to show this phenomenon is to build the model of an airplane and its control
system and then perform simulations on this plane with Matlab-Simulink software. The
equations of flight dynamics used are the linear and the non-linear equations of dynamics
given by Mc Lean 1990. The simulation is performed on a Douglas DC-8 with the help of
derivatives data given by Mc Ruer 1995.
The model of the plane is built in different parts: flight dynamics model, pilot model, actuator
model and control model. Then these parts are integrated in a bigger model representing the
whole airplane with its controls. After checking that the aircraft is stable, a big gain
representing a wrong reaction of the pilot is put inside this model. Then the plane starts to
oscillate: the Pilot Induced Oscillations appear.
So, this report clearly shows that the PIO are caused by an overreaction of the pilot inside the
loop of the control system.