Pilot and control system modelling for handling qualities analysis of large transport aircraft

摘要

The notion of airplane stability and control being a balancing act betweenstability and control has been around as long as aeronautics. The Wrightbrothers’ first successful flights were born of the debate, and were successful atleast in part because they spent considerable time teaching themselves how tocontrol their otherwise unstable airplane.This thesis covers four aspects of handling for large transport aircraft: largesize and the accompanying low frequency dynamics, the way in which liftingsurfaces and control system elements are modelled in flight dynamics analyses,the cockpit feel characteristics and details of how pilots interact with them, andthe dynamic instability associated with Pilot Induced Oscillations.The dynamics associated with large transport aircraft are reviewed from theperspective of pilot-in-the-loop handling qualities, including the effects ofrelaxing static stability in pursuit of performance. Areas in which current designrequirements are incomplete are highlighted. Issues with modelling of dynamicelements which are between the pilot’s fingers and the airplane response areilluminated and recommendations are made.Cockpit feel characteristics are examined in detail, in particular, the nonlinearelements of friction and breakout forces. Three piloted simulation experimentsare described and the results reviewed. Each was very different in nature, andall were designed to evaluate linear and nonlinear elements of the cockpit feelcharacteristics from the pilot’s point of view. These included understanding thepilot’s ability to precisely control the manipulator itself, the pilot’s ability tocommand the flight path, and neuro-muscular modelling to gain a deeperunderstanding of the range of characteristics pilots can adapt to and why.Based on the data collected and analyzed, conclusions are drawn andrecommendations are made. Finally, a novel and unique PIO prediction criterion is developed, which is basedon control-theoretic constructs. This criterion identifies unique signatures in thedynamic response of the airplane to predict the onset of instability.