A practical biodynamic feedthrough model for helicopters

Abstract

Biodynamic feedthrough (BDFT) occurs when vehicle accelerations feed through the pilot’s body and cause involuntary motions of limbs, resulting in involuntary control inputs. BDFT can severely reduce ride comfort, control accuracy and, above all, safety during the operation of rotorcraft. Furthermore, BDFT can cause and sustain rotorcraft-pilot couplings. Despite many different studies conducted in past decades—both within and outside of the rotorcraft community—BDFT is still a poorly understood phenomenon. The complexities involved in BDFT have kept researchers and manufacturers in the rotorcraft domain from developing robust ways of dealing with its effects. A practical BDFT pilot model, describing the amount of involuntary control inputs as a function of accelerations, could pave the way to account for adverse BDFT effects. In the current paper, such a model is proposed. Its structure is based on the model proposed by Mayo (15th European Rotorcraft Forum, Amsterdam, pp. 81-001–81-012 1989), and its accuracy and usability are improved by incorporating insights from recently obtained experimental data. An evaluation of the model performance shows that the model describes the measured data well and that it provides a considerable improvement to the original Mayo model. Furthermore, the results indicate that the neuromuscular dynamics have an important influence on the BDFT model parameters.