title: A novel method of using accelerometry for upper limb FES control.
abstract: This paper reports on a novel approach to using a 3-axis accelerometer to capture body segment angle for upper limb functional electrical stimulation (FES) control. The approach calculates the angle between the accelerometer x-axis and the gravity vector, while avoiding poor sensitivity at certain angles and minimizing errors when true acceleration is relatively large in comparison to gravity. This approach was incorporated into a state-machine controller which is used for the real-time control of FES during upper limb functional task performance. An experimental approach was used to validate the new method. Two participants with different upper limb impairments resulting from a stroke carried out four different FES-assisted tasks. Comparisons were made between angle calculated from arm-mounted accelerometer data using our algorithm and angle calculated from limb-mounted reflective marker data. After removal of coordinate misalignment error, mean error across tasks and subjects ranged between 1.4 and 2.9°. The approach shows promise for use in the control of upper limb FES and other human movement applications where true acceleration is relatively small in comparison with gravity.
authors.affiliation: Centre for Health Sciences Research, University of Salford, Salford M6 6PU, UK.
authors.forename: Mingxu
authors.initials: M
authors.lastname: Sun
authors.affiliation: Centre for Health Sciences Research, University of Salford, Salford M6 6PU, UK. Electronic address: l.p.j.kenney@salford.ac.uk.
authors.forename: Laurence
authors.initials: L
authors.lastname: Kenney
authors.affiliation: Department of Allied Health Professions, Collegiate Crescent, Sheffield, South Yorkshire S10 2BP, UK.
authors.forename: Christine
authors.initials: C
authors.lastname: Smith
authors.affiliation: Centre for Health Sciences Research, University of Salford, Salford M6 6PU, UK.
authors.forename: Karen
authors.initials: K
authors.lastname: Waring
authors.affiliation: Centre for Health Sciences Research, University of Salford, Salford M6 6PU, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Luckie
authors.affiliation: Centre for Health Sciences Research, University of Salford, Salford M6 6PU, UK.
authors.forename: Anmin
authors.initials: A
authors.lastname: Liu
authors.affiliation: Centre for Health Sciences Research, University of Salford, Salford M6 6PU, UK; School of Computing, Science and Engineering, University of Salford, Salford M5 4WT, UK.
authors.forename: David
authors.initials: D
authors.lastname: Howard
mesh_terms: D061725:Accelerometry / Q000295:instrumentation*; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D006112:Gravitation; D006801:Humans; D034941:Upper Extremity
keywords: Accelerometer; Body segment angle; Functional electrical stimulation control; Functional tasks; Upper limb rehabilitation