Numerical Investigation on the Role of Control Inceptors Layout in Rotorcraft-Pilot Couplings

Aeroelastic rotorcraft-pilot couplings are dynamic phenomena in which the vibrations of a rotorcraft are transmitted through the cockpit, the seat and the control inceptors to the pilot, and the resulting induced motion is involuntarily fed back into the control system. Handling qualities, in terms of ability to complete the desired task, and even safety of flight can be affected by the proneness of the rotorcraft to giving rise to adverse interactions, an unwanted characteristic that can be captured by the so-called biodynamic feedthrough. In this work, a multibody model of the whole upper body, developed by the authors, is used to support the design of the control inceptors. The sensitivity of biodynamic feedthrough to the characteristics of cockpit layout and inceptors is analyzed varying several parameters: the length and inertia of the inceptors, the effect of the trim spring and of the compliance of the seat cushion. The simulations encompass subjects of different anthropometric data, in order to represent possible intra-subject variations. Biodynamic feedthrough at collective and cyclic inceptors, in response to vertical acceleration inputs, is discussed along with single-harmonic, large-magnitude input responses that highlight the presence and importance of nonlinearities.