title: Impedance control complements incomplete internal models under complex external dynamics.
abstract: In this paper, we investigate motor adaptation of human arm movements to external dynamics. In an experiment, we tried to determine whether humans can learn an internal model of a mixed force field (V+P) that was the sum of a velocity-dependent force field (V) and a position-dependent force field (P). The experimental results show that the subjects did not learn the internal model of V+P accurately and they compensated for the loads by using impedance control. Our results suggest that humans use impedance control when internal models become inaccurate because of the complexity of the external dynamics.
authors.affiliation: Department of Computational Intelligence and Systems Science, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama-shi, Kanagawa, Japan. naoki@ito.dis.titech.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Tomi
authors.forename: Manabu
authors.initials: M
authors.lastname: Gouko
authors.forename: Koji
authors.initials: K
authors.lastname: Ito
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D005246:Feedback / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D009048:Motor Skills / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D013314:Stress, Mechanical; D013647:Task Performance and Analysis; D014783:Viscosity; D055815:Young Adult