Now showing 1 - 2 of 2
  • Publication
    Functionally biarticular control for smart prosthetics
    In this paper we introduce the use of force feedback in conjunction with myoelectric control to establish an improved interface for a powered prosthetic limb. The force feedback is delivered through a single-axis exoskeleton worn about the elbow, while the EMG signal is derived from the biceps muscle. This combination is intended to produce a sense of effort in the biceps that is associated with the action of the motorized prosthetic gripper. The method engages both efferent and afferent signals innervating a functional muscle with the aim of realizing a muscle that is effectively biarticular. The controlling muscle spans one joint physiologically and a second, prosthetic joint functionally. Preliminary experiments have demonstrated that force feedback can substitute for vision during grasp and lift tasks.
      975Scopus© Citations 6
  • Publication
    Passive and active kinesthetic perception just-noticeable-difference for natural frequency of virtual dynamic systems
    This paper investigates the just-noticeable-difference (JND) for natural frequency of virtual second order dynamic systems. Using a one degree-of-freedom haptic device, visual and/or haptic sensory feedback were presented during interactions with the system. Participants were instructed to either perceive passively or actively excite the system in order to discriminate natural frequencies. The JND for this virtual resonance task ranged from 3.99% to 6.96% for reference frequencies of 1 Hz and 2 Hz. Results show that sensory feedback has a significant effect on JND in passive perception, with combined visual and haptic feedback enabling the best discrimination performance. In active perception, there is no significant difference on JND with haptic and combined visual and haptic feedback. There is also no significant difference between active perception and passive perception for this JND experiment. The presentation of systems with equivalent natural frequencies but different spring stiffness resulted in no large bias toward larger stiffness and no significant difference in JND for equivalent systems. This finding indicates that human participants do not discriminate natural frequency based on the maximum force magnitude perceived, as indicated by prior studies.
      1443Scopus© Citations 2