IEEE Trans Neural Syst Rehabil Eng
December 2020
This article presents an analytical method that offers both spectral and spatial information to predict local electric fields capable of driving neural activities for neuromuscular activation, and the findings of an experimental investigation on a common strategy utilizing multiple high-frequency (HF) electric fields to create an interference to recruit neural firing at depth. By introducing a cut-off frequency [Formula: see text] too high to recruit neural firing in a frequency-based field descriptor, the analytical method offers an effective means to position a focused temporal interference (TI) without mechanically moving the electrodes. The experiment, which was conducted on both forearms of five healthy volunteers, validates the feasibility of the method for selective neuromuscular stimulation, where three nerve/muscles that control human fingers were independently stimulated with two current channels.
View Article and Find Full Text PDFIEEE Trans Neural Syst Rehabil Eng
September 2020
Loaded walking with a rucksack results in both gravitational and inertial forces of the load that must be borne by human carriers. The inertial force may be the source of metabolic burden and musculoskeletal injuries. This paper presents a lightweight backpack with a disturbance observer-based acceleration control to minimize the inertial force.
View Article and Find Full Text PDFWearable devices developed with flexible electronics have great potential applications for human health monitoring and motion sensing. Although material softness and structural flexibility provide a deformable human-machine interface to adapt to joint bending or tissue stretching/compression, flexible sensors are inconvenient in practical uses as they usually require calibration every time they are installed. This article presents an approach to design and fabricate a flexible curvature sensor to measure human articular movements for amphibious applications.
View Article and Find Full Text PDFLocalization of active neural source (ANS) from measurements on head surface is vital in magnetoencephalography. As neuron-generated magnetic fields are extremely weak, significant uncertainties caused by stochastic measurement interference complicate its localization. This paper presents a novel computational method based on reconstructed magnetic field from sparse noisy measurements for enhanced ANS localization by suppressing effects of unrelated noise.
View Article and Find Full Text PDFProc Inst Mech Eng H
February 2015
This article presents a multi-motion control system to help severe disabled people operate an auxiliary appliance using neck-up bioelectric signals measured by a single-channel dry electrode on the forehead. The single-channel dry-electrode multi-motion control system exhibits several practical advantages over its conventional counterparts that use multi-channel wet-electrodes; among the challenges is an effective technique to extract bioelectric features for reliable implementation of multi degrees-of-freedom motion control. Using both time and frequency characteristics of the single-channel dry-electrode measurements, motion commands are derived from multiple feature signals associated with concentration demands and different eye-blink actions for use in a two-level control strategy that has been developed to control predefined multi degrees-of-freedom motion trajectories.
View Article and Find Full Text PDFRev Sci Instrum
December 2011
A method based on binocular vision servoing for positioning of a diagnostic package in inertial confinement fusion (ICF) experiments is presented. The general diagnostic instrument manipulator will provide precision three dimension positioning and alignment-to-target capability in ICF experiments. In this work, we focus on the final precise automatic positioning with a binocular vision system.
View Article and Find Full Text PDFThis paper presents a knee-joint model to provide a better understanding on the interaction between natural joints and artificial mechanisms for design and control of rehabilitation exoskeletons. The anatomically based knee model relaxes several commonly made assumptions that approximate a human knee as engineering pin-joint in exoskeleton design. Based on published MRI data, we formulate the kinematics of a knee-joint and compare three mathematical approximations; one model bases on two sequential circles rolling a flat plane; and the other two are mathematically differentiable ellipses-based models with and without sliding at the contact.
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