Modelling and control of paraplegic’s knee joint (fes-swinging)
The use of electrical signals to restore the function of paralyzed muscles is called functional electrical stimulation (FES). FES is a promising method to restore mobility to individuals paralyzed due to spinal cord injury (SCI). This thesis is concerned with the development of an accurate parapl...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2011
|
| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/2988/1/24p%20BABUL%20SALAM%20KADER%20IBRAHIM.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | The use of electrical signals to restore the function of paralyzed muscles is called
functional electrical stimulation (FES). FES is a promising method to restore
mobility to individuals paralyzed due to spinal cord injury (SCI). This thesis is
concerned with the development of an accurate paraplegic knee joint model and
control of electrically stimulated muscle. The modelling of musculoskeletal of
paraplegic’s lower limb is significantly challenging due to the complexity of the
system. The first aim of this study is to develop a knee joint model capable of
relating electrical parameters to dynamic joint torque as well as knee angle for FES
application. The knee joint is divided into 3 parts; active muscle properties, passive
knee joint properties and lower limb dynamics Hence the model structure
comprising optimised equations of motion and fuzzy models to represent the passive
viscoelasticity and active muscle properties is formulated. The model thus
formulated is optimised using genetic optimization, and validated against
experimental data. The results show that the model developed gives an accurate
dynamic characterisation of the knee joint. The second aim of this study is to
develop FES-induced swinging motion control. A crucial issue of FES is the control
of motor function by artificial activation of paralyzed muscles. Major problems that
limit the success of current FES control systems are nonlinearity of the
musculoskeletal system and rapid change of muscle properties due to fatigue. Fuzzy
logic control (FLC) with its ability to handle a complex nonlinear system without
mathematical model is used. Two FLC strategies; trajectory based control and cycleto-cycle
control are developed. In the trajectory
based control, the
controller
with
less
energy consumption
is developed to reduce muscle
fatigue. The ability of this
controller
to
minimize
the
fatigue
is proved in the
experimental
work. The
discretetime
cycle-to-cycle control strategy is developed
without predefined trajectory. This
strategy
is applicable for
controlling FES-induced
movement
with the ability to
reach
full knee
extension
angle and
to maintain
a steady swinging of the lower limb
as
desired in
the presence
of muscle
fatigue
and spasticity. The performances
of the
controllers are assessed through simulation study and validated through
experimental work. |
|---|