Multibody Dynamics Modelling of a Passive Pilot for Aircraft-Pilot-Coupling Investigation

As civil and business aircraft increasingly incorporate lightweight materials and reduce airframe weights to optimize efficiency, airframes have generally become more flexible with less structurally damped vibrational modes. This has caused an increase in the occurrence of a phenomenon known as Aircraft-Pilot-Coupling (APC). APC occurs when an airframe's structural vibrational modes impinge on the bandwidth of a pilot's biodynamics, resulting in adverse interactions between passive pilot dynamics and the aircraft's control system and aeroservoelastic responses. Simulations are advantageous in the studying of APC, as they can be run during the design phase of an aircraft, allowing APC mitigation to be performed before an aircraft model takes flight. Simulating APC requires a dedicated passive pilot biodynamic model. While some models exist in literature, they typically are analytical 2-dimensional models, with many simplifications and limitations. This paper details the development of two pilot biodynamic models created within a multibody dynamics simulation software. The first model, composed of two 2D models, aims to recreate a recently developed detailed 2D analytical model to explore the capabilities of multibody dynamics simulations of 2D pilot biodynamic models. Parametric studies are outlined, allowing a direct comparison between the developed 2D model and the analytical model, alongside experimental data. The second model described in this paper builds off the first but consists of a single 3D model. For the 3D model, particle swarm optimization techniques were employed to tune the joint stiffness and damping values to the available experimental data. Identical parametric studies were performed allowing a comparison between the models and experimental data. Overall, the models both demonstrate notable results, accurately reproducing pilot response trends exhibited by the analytical model and by experimental results. Comparing error between the frequency response of the models and the available experimental data, it was found that the 3D model demonstrates significant improvements upon the multi-body dynamics 2D model and the analytical2D model, capturing characteristics of the experimental data that the 2D models were incapable of. Furthermore, the advanced abilities of the 3D model in performing simulation with multi-dimensional inputs and coupling between dimensions are demonstrated, further indicating the significance of the 3D model being presented.