Key problems & objectives

ARISTOTEL identified six key problems specifically related to Aircraft-and-Rotorcraft Pilot Couplings (A/RPC) analysis which represent, at the same time, the project's objectives.

Key problem #1:

Is a particular event an A/RPC at all? When analysing oscillatory behaviour we first have to find out if this particular event is an A/RPC or not. Therefore, the ARISTOTELians updated the existing A/RPC definition and decided that the following definition of A/RPC events be used throughout the project: An aircraft- or rotorcraft-pilot coupling (A/RPC) is an unintentional (inadvertent) sustained or uncontrollable vehicle oscillation characterized by a mismatch between the pilot’s mental model of the vehicle dynamics and the actual vehicle dynamics. The result is that the pilot's control input is out-of-phase with the response of the vehicle, possibly causing a diverging motion.

Key problem #2:

To date, there is a lack of quantitative pilot behavioural models. The possible interactions between the flight control system and the pilot are hardly understood. As a matter of course the ARISTOTEL project will develop such models in order to gain a deep understanding of possible interactions.

Key problem #3:

Here, ARISTOTEL concentrates especially on rotorcraft. In current rotorcraft modelling for RPC analysis, research is rather limited to the particular case analysed and does not take into account the massive interactions existing between aerodynamics, structures and other control systems; there is no high-fidelity comprehensive model that is generally applicable to RPCs and also no guidelines as to how much detail should be included in the model. Here again, ARISTOTEL tackles this problem by developing the required vehicle models.

Key problem #4:

Despite numerous attempts to define design criteria that will result in an aircraft free of RPC tendencies, A/RPC events have stubbornly refused to go away. Even more so, with highly augmented rotorcraft becoming more prevalent, it assumed that RPC events will increase. The ARISTOTEL consortium will therefore develop, extend and improve the current A/RPC criteria.

Key problem #5:

To date simulator and flight tests do not possess the proper practices to reveal the A/RPC signature. With the protocols for training in the simulator the ARISTOTELians will develop, this problem can be overcome.

Key problem #6:

No coherent design guide or simulator guidelines are available to the designer for revealing A/RPCs. As a matter of fact, another project outcome will be those needed guidelines.