Iterative learning control of drop foot stimulation with array electrodes for selective muscle activation
Valtin M, Seel T, Raisch J, Schauer T (2014)
Publication Type: Conference contribution
Publication year: 2014
Journal
Publisher: IFAC Secretariat
Book Volume: 19
Pages Range: 6587-6592
Conference Proceedings Title: IFAC Proceedings Volumes (IFAC-PapersOnline)
Event location: Cape Town
ISBN: 9783902823625
DOI: 10.3182/20140824-6-za-1003.01991
Abstract
Disorders of the central nervous system like stroke often lead to a paresis of the muscles responsible for dorsiflexion and eversion of the foot during swing phase. Functional electrical stimulation (FES) is commonly used to improve the foot movement. A precise placement of two single surface electrodes on the shank as well as a manual tuning of heel-switch triggered stimulation is required when using standard drop-foot stimulators. In this work, the use of automatically tuned array electrodes for selective nerve/muscle stimulation and the application of iterative learning control for adjusting stimulation intensities are investigated with the aim to obtain an optimal foot movement. The stimulation effect is observed by means of two inertial measurement units mounted on the foot and shank, respectively. Two array electrodes are placed over the areas covering the peroneal nerve and the muscle tibialis anterior. A fast identification procedure finds three suitable sets of array elements, forming so-called virtual electrodes, in both arrays. Two stimulation channels are established over the three virtual electrodes. Both channels produce dorsiflexion, but one promotes eversion and the other inversion. A decoupling matrix is applied to the stimulation intensities of both channels in order to obtain independent control over dorsiflexion and eversion. Finally, two independent iterative learning controllers are employed to achieve desired angle profiles. The proposed stimulation and control scheme is initially tested on a healthy person sitting on a table with the shank and foot free to swing. A tracking RMS error of less than one degree is achieved within six walking steps.
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Germany (DE)How to cite
APA:
Valtin, M., Seel, T., Raisch, J., & Schauer, T. (2014). Iterative learning control of drop foot stimulation with array electrodes for selective muscle activation. In Edward Boje, Xiaohua Xia (Eds.), IFAC Proceedings Volumes (IFAC-PapersOnline) (pp. 6587-6592). Cape Town, ZA: IFAC Secretariat.
MLA:
Valtin, M., et al. "Iterative learning control of drop foot stimulation with array electrodes for selective muscle activation." Proceedings of the 19th IFAC World Congress on International Federation of Automatic Control, IFAC 2014, Cape Town Ed. Edward Boje, Xiaohua Xia, IFAC Secretariat, 2014. 6587-6592.
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