Enabling
the development of efficient exoskeletons
by means of human movement
experiments
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WALL-X is a simple pneumatically
powered
robotic exoskeleton developed by the
lab of
Movement Science of Ghent University
that assists ankle push-off, thus making walking easier. Traditionally, labs
working on robotic exoskeletons have been focusing on the technological
aspect. As movement scientists we focus on the human inside the device. We
typically conduct experiments where we change the actuation pattern of the
exoskeleton and measure the effect on the user via oxygen consumption
measurement and motion capture techniques.
This approach was highly
successful as in 2013 our simple but experimentally optimized exoskeleton
was the first ever worldwide to be able to reduce the metabolic cost
below the cost of walking with normal shoes.
Put simply, this means that walking with the Ghent University exoskeleton
requires less effort than walking with your normal shoes.
While practical use of exoskeletons seems to be something from science fiction the first exoskeletons have become commercially available over the last few years. It is expected that exoskeletons will replace wheeled devices such as mobility scooters for clinical populations such as stroke patients or elderly. In addition to advances in engineering, it is crucial to gain understanding on the presently insufficiently known human neuromechanics during assisted locomotion via movement science research methods.
Our mission is to enable the rise of a new generation of exoskeletons that augment mobility to a clearly perceivable degree, in able-bodied as well as impaired persons, by optimizing assistance patterns based on evidence from human neuromechanics experiments.
Companies or researchers who are interested to become
involved in this project are highly welcome to reach out to us via the
contact
details at the bottom of this webpage. For companies we have a specific
technology opportunity document.
Figure: Typical research
approach for studying human neuromechanics during exoskeleton walking.
1)
Experimental optimization of exoskeleton actuation pattern for reducing the
metabolic cost of walking.
Representative study:
Malcolm P, Derave W, Galle S, De Clercq D: A Simple Exoskeleton that Assists
Plantarflexion Can Reduce the Metabolic Cost of Human Walking.
PLoS One 2013, 8:e56137.
2) Biomechanics and physiology of human adaptation
to exoskeleton assistance during walking.
Representative studies:
- Galle S, Malcolm P, Derave W, De Clercq D: Enhancing performance during
inclined loaded walking with a powered
ankle-foot exoskeleton.
Eur J Appl Physiol 2014.
- Galle S, Malcolm P, Derave W, De Clercq D: Adaptation to walking with an
exoskeleton that assists ankle extension.
Gait Posture 2013, 38:495–499.
3) Application of an exoskeleton that reduces
metabolic cost of walking in clinical populations.
Representative study:
Galle S, Malcolm P, Derom E, Calders P, De Clercq D. Pilot test of a
Wearable Assistive Lower Leg eXoskeleton in patients. In preparation.
4) Use of an exoskeleton as an experimental tool
for investigating neuromechanics of human gait.
Representative study:
Malcolm P, Fiers P, Segers V, Van Caekenberghe I, Lenoir M, De Clercq D:
Experimental study on the role of the ankle push off in the walk-to-run
transition by means of a powered ankle-foot-exoskeleton.
Gait Posture 2009, 30:322–327.
While it was known by now that exoskeletons can reduce
the metabolic cost of walking at normal intensity it was unsure whether
subjects would still benefit from the exoskeleton during maximum intensity
efforts. Our new paper shows that with the help of our exoskeleton subjects
reach exhaustion at their normal physiological parameters but at a higher
external workload. This signifies that aside from restoring patient mobility
another possible application of exoskeletons could be allowing healthy
subjects to transcend their biological limits.
Reference:
Galle S, Malcolm P, Derave W, De Clercq D: Enhancing performance during
inclined loaded walking with a powered ankle-foot exoskeleton.
Eur J Appl Physiol 2014.
About one year after the Ghent University exoskeleton,
two very recent studies with exoskeletons also broke the normal-walking
barrier, this time with fully autonomous exoskeletons.
In the
study
from MIT this result was
achieved using the
optimal timing
and
required adaptation period that were discovered by research with the Ghent University
exoskeleton thus indirectly
confirming the practical relevance of our own research.
The
second
study uses exclusively elastic actuation which means that
this exoskeleton has unrestricted autonomy. Both results clearly demonstrate
that it is possible to assist ‘free’ walking with exoskeletons which
emphasizes the opportunities of this new technology for assisting mobility
in clinical populations (cfr. own research line no. 3) . Congratulations to
Mooney, Rouse and Herr from
MIT
and Wiggin, Collins and Sawicki from
NCSU
and
CMU
for their exciting results.
Several leading authorities in the field of walking biomechanics and
robotics were given the opportunity to experience firsthand how it feels to
walk with the Ghent University exoskeleton.
This result was obtained
by optimizing actuation timing confirming a hypothesis from
a mathematical model of walking
saying that push-off timing is important. Previously, no exoskeletons from
university labs or commercial companies were able to reduce metabolic cost
below the level of walking without exoskeleton. This result gets covered in
national television and popular scientific press.
VTM News, February 18, 2013: “Prolonged walking with
Robot Shoe”.
EOS Magazine,
February
15, 2013, I-pad edition:
“Wearable robots”.
§ This research is supported by BOF10/DOC/288 (drs. S. Galle, Prof. D. De Clercq, Prof. W. Derave).
§ Technische Orthopedie België (www.orthoshop.be) has been helping us since the very beginning in 2007 by custom-designing the different iterations of the orthotic part of our exoskeletons.
·
Steve Collins, Carnegie Mellon University.
In 2013, Philippe Malcolm from Ghent University was given the opportunity
to
study the effect of push-off timing now using the robotic prosthesis
emulator from Caputo and Collins
at the
lab of Experimental Biomechatronics
of Carnegie Mellon University
·
Delft University of Technology,
Biorobotics lab
·
University of Twente
Neuromechanics and Biomechatronics section
·
Industrial Design Center,
Ghent University, Campus Kortrijk
·
Eric Derom and Patrick Calders of the
Department of Physical Therapy and Motor Rehabilitation
of the Ghent University
Hospital
·
Joris Degrieck of the
Department of Materials Science and Engineering
of Ghent University has supported our research
with improvements in the
actuator attachments, force sensing and modeling of our exoskeleton.
· Wim Derave, Ghent University Department of Movement and Sports Sciences, lab of exercise physiology.
We are highly interested in partnerships with:
·
Companies who are interested in using our database of optimal actuation
and/or optimization method and infrastructure
(see
technology opportunity document)
·
Engineering scientists who are interested in working on the hardware and/or
control of our exoskeletons.
·
Scientists who are interested in using our experimental data to develop and
validate simulation models of exoskeleton-assisted walking.
·
Clinicians who are interested to test the exoskeleton in specific patients
populations.
·
Engineering labs who develop exoskeletons or prostheses looking for support
with conducting walking experiments to test their
designs.
From 2015 we will
have a
brand new lab
and
equipment
that is optimally suited to this end.
·
Orthopedic, pneumatic, electronic or mechatronic suppliers who are
interested to sponsor the material needs of our
research.
You are welcome to contact drs.
Samuel Galle to
discuss collaboration opportunities.
E-mail:
samuel.galle@ugent.be
Telephone: 0032/9.264.94.37
