Details
| Original language | English |
|---|---|
| Pages (from-to) | 8786-8791 |
| Number of pages | 6 |
| Journal | IFAC-PapersOnLine |
| Volume | 50 |
| Issue number | 1 |
| Publication status | Published - Jul 2017 |
Abstract
Functional Electrical Stimulation (FES) can be used to support the gait of stroke patients. By measuring joint angles and adjusting the stimulation intensities automatically to the current need of the patient, setup times can be reduced and time-variant effects like muscle fatigue can be compensated. This was achieved in recent publications by using Iterative Learning Control (ILC) on the ankle complex. In this paper we consider FES of the antagonistic knee muscle complex (quadriceps and hamstring muscles) that controls knee flexion/extension. We used a coactivation strategy in order to map the two stimulation channels to a single control input. A large class of dynamic models was obtained by system identification based on data from two experiments: one with standing subjects and one with subjects walking on a treadmill while being stimulated during different time segments of the gait cycle. Time delays, system poles, and in particular the system gains were found to vary largely. Furthermore, large differences were observed between muscle dynamics in standing pose and during walking. We designed an iterative learning controller that is stable for almost all models. In experiments with eight healthy subjects walking on a treadmill, the ILC was found to reduce deviations from a reference trajectory to about five degrees within two strides.
Keywords
- adaptive, functional electrical stimulation (FES), gait, iterative learning control (ILC), knee angle, multichannel, neuroprosthesis, stroke rehabilitation, system identification
ASJC Scopus subject areas
- Engineering(all)
- Control and Systems Engineering
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In: IFAC-PapersOnLine, Vol. 50, No. 1, 07.2017, p. 8786-8791.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Iterative learning control and system identification of the antagonistic knee muscle complex during gait using functional electrical stimulation
AU - Müller, Philipp
AU - Balligand, Cécile
AU - Seel, Thomas
AU - Schauer, Thomas
PY - 2017/7
Y1 - 2017/7
N2 - Functional Electrical Stimulation (FES) can be used to support the gait of stroke patients. By measuring joint angles and adjusting the stimulation intensities automatically to the current need of the patient, setup times can be reduced and time-variant effects like muscle fatigue can be compensated. This was achieved in recent publications by using Iterative Learning Control (ILC) on the ankle complex. In this paper we consider FES of the antagonistic knee muscle complex (quadriceps and hamstring muscles) that controls knee flexion/extension. We used a coactivation strategy in order to map the two stimulation channels to a single control input. A large class of dynamic models was obtained by system identification based on data from two experiments: one with standing subjects and one with subjects walking on a treadmill while being stimulated during different time segments of the gait cycle. Time delays, system poles, and in particular the system gains were found to vary largely. Furthermore, large differences were observed between muscle dynamics in standing pose and during walking. We designed an iterative learning controller that is stable for almost all models. In experiments with eight healthy subjects walking on a treadmill, the ILC was found to reduce deviations from a reference trajectory to about five degrees within two strides.
AB - Functional Electrical Stimulation (FES) can be used to support the gait of stroke patients. By measuring joint angles and adjusting the stimulation intensities automatically to the current need of the patient, setup times can be reduced and time-variant effects like muscle fatigue can be compensated. This was achieved in recent publications by using Iterative Learning Control (ILC) on the ankle complex. In this paper we consider FES of the antagonistic knee muscle complex (quadriceps and hamstring muscles) that controls knee flexion/extension. We used a coactivation strategy in order to map the two stimulation channels to a single control input. A large class of dynamic models was obtained by system identification based on data from two experiments: one with standing subjects and one with subjects walking on a treadmill while being stimulated during different time segments of the gait cycle. Time delays, system poles, and in particular the system gains were found to vary largely. Furthermore, large differences were observed between muscle dynamics in standing pose and during walking. We designed an iterative learning controller that is stable for almost all models. In experiments with eight healthy subjects walking on a treadmill, the ILC was found to reduce deviations from a reference trajectory to about five degrees within two strides.
KW - adaptive
KW - functional electrical stimulation (FES)
KW - gait
KW - iterative learning control (ILC)
KW - knee angle
KW - multichannel
KW - neuroprosthesis
KW - stroke rehabilitation
KW - system identification
UR - http://www.scopus.com/inward/record.url?scp=85031821187&partnerID=8YFLogxK
U2 - 10.1016/j.ifacol.2017.08.1738
DO - 10.1016/j.ifacol.2017.08.1738
M3 - Article
VL - 50
SP - 8786
EP - 8791
JO - IFAC-PapersOnLine
JF - IFAC-PapersOnLine
SN - 2405-8963
IS - 1
ER -