title: Acceleration feedback improves balancing against reflex delay.
abstract: A model for human postural balance is considered in which the time-delayed feedback depends on position, velocity and acceleration (proportional-derivative-acceleration (PDA) feedback). It is shown that a PDA controller is equivalent to a predictive controller, in which the prediction is based on the most recent information of the state, but the control input is not involved into the prediction. A PDA controller is superior to the corresponding proportional-derivative controller in the sense that the PDA controller can stabilize systems with approximately 40 per cent larger feedback delays. The addition of a sensory dead zone to account for the finite thresholds for detection by sensory receptors results in highly intermittent, complex oscillations that are a typical feature of human postural sway.
authors.affiliation: Department of Applied Mechanics, Budapest University of Technology and Economics, 1521 Budapest, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Insperger
authors.forename: John
authors.initials: J
authors.lastname: Milton
authors.forename: Gábor
authors.initials: G
authors.lastname: Stépán
mesh_terms: D000054:Acceleration; D001696:Biomechanical Phenomena; D056228:Feedback, Sensory / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D004856:Postural Balance / Q000502:physiology*; D012018:Reflex / Q000502:physiology*