title: An airjet actuator system for identification of the human arm joint mechanical properties.
abstract: A system is described for determining the mechanical properties of the human arm during unconstrained posture and movement. An airjet perturbation device is attached to the wrist with a special cuff, and provides high-frequency stochastic perturbations in potentially three orthogonal directions. The airjet operates as a fluidic flip-flop utilizing the Coanda effect, and generates binary force sequences with a steady-state thrust of 4 N, a flat frequency response to 75 Hz, usable thrust to 150 Hz, and a rise time of 1 ms, when the static pressure at the nozzle inlet is 5.5 x 10(5) Pa (80 psi). These operating characteristics are adequate to identify the arm's mechanical properties efficiently and robustly.
authors.affiliation: Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
authors.lastname: Xu YMj
authors.forename: I W
authors.initials: IW
authors.lastname: Hunter
authors.forename: J M
authors.initials: JM
authors.lastname: Hollerbach
authors.forename: D J
authors.initials: DJ
authors.lastname: Bennett
mesh_terms: D000388:Air; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D004864:Equipment and Supplies; D006801:Humans; D007596:Joints / Q000502:physiology*; D009068:Movement