Identification of the Feedback Components of the Neuromuscular System in a Pitch Control Task

This goal of this study is to understand which parts of the the neuromuscular system contribute during a pitch control task. A novel method developed at the Delft University of Technology allows us to determine the contribution of the neuromuscular feedback system by identifying the admittance, which is the frequency response function of the yielded displacement due to an external force perturbation which applied to control inceptor. In an experiment in a full-motion flight simulator, the neuromuscular admittance was identified during a longitudinal pitch tracking task with a side stick, for two different side stick configurations, an approach configuration with a relatively low stick stiffness, and a cruise configuration with a high stiffness. Besides the admittance, also the muscle activity of eleven muscles was measured. To validate whether the external force perturbation changed the control behavior of the pilot, the visual and vestibular response functions were identified as well. From the measured results it could be concluded that the variations of the control inceptor settings had a significant effect on the neuromuscular feedback system (admittance), although the overall lumped neuromuscular system did not change significantly. A very interesting finding were the very high levels of co-contraction measured during the pitch tracking tasks. And lastly it could be concluded that the required external force perturbation did not affect the control behavior