1. • A deep exploration of the physical and electronic
landscape of the University of Central Lancashire
(UCLAN) was performed to navigate to
challenging areas where change may improve the
potential for exoskeleton research within UCLAN..
System Interoperability for Exoskeletons
M.M. Martinez supervised by B.A. Piorkowski
School of Computing, Engineering and Physical Sciences, University of Central Lancashire
Abstract
During the last few years the exoskeleton concept has been transformed from a science fiction device to a research field with considerable scope for
progression. A sensor network and hardware control architecture to be used in a powered exoskeletal foot ankle orthosis has been proposed. The proposed
system intends to improve communication networking and sensor network efficiency. The sensor network is exclusively based on Inertial Measurement Units
(IMUs) and pressure sensors. The hardware control architecture is intended to be distributed and highly modular featuring low-latency high bandwidth real-
time communication. A deep exploration of the physical and electronic landscape of the University of Central Lancashire (UCLAN) was performed to assess
the suitability of available industrial and the clinical biomechanics technology for exoskeleton development.
Introduction
Robotic and mechatronic products have been applied into many industrial and commercial sectors An
exoskeleton requires a network of sensors to interact with the human body and the external environment.
These sensor network could be based either in the measurement of biomechanical parameters or in the muscle
activity. Inertial Measurement Units (IMUs) are capable of estimating the ankle joint angles with signal
processing techniques. The University of Central Lancashire (UCLAN) has world-leading experience in
industrial robotics with the centre for Advanced Digital Manufacturing Technology (ADMT) and also in
clinical biomechanics with a state-of-the art movement analysis laboratory working in collaboration with the
National Health Service (NHS). Careful analysis of the interoperability of technology for exoskeletons is
necessary to leverage knowledge from the ADMT to support the development of a biomechatronic
exoskeleton in UCLAN.
Aim and Objectives
Methodology
Results
Conclusion • ATTON, S. Choosing the Right Prioritisation Method.
Software Engineering, 2008. ASWEC 2008. 19th
Australian Conference on, 26-28 March 2008 2008. 517-
526.
• HERR, H. 2009. Exoskeletons and orthoses:
classification, design challenges and future directions.
BioMed Central.
• LEVINE, D., RICHARDS, J. & WHITTLE, M. W. 2012.
Whittle's Gait Analysis, Elsevier - Health Sciences
Division.
• PARK, Y.-L., CHEN, B.-R., YOUNG, D., STIRLING, L.,
WOOD, R. J., GOLDFIELD, E. & NAGPAL, R. Bio-
inspired active soft orthotic device for ankle foot
pathologies. Intelligent Robots and Systems (IROS),
2011 IEEE/RSJ International Conference on, 25-30 Sept.
2011 2011. 4488-4495.
• RICHARDS, J. 2008. Biomechanics in Clinic and Research:
An Interactive Teaching and Learning Course, Churchill
Livingstone/Elsevier.
References
The step-by-step research objectives are to:-
1. Analyse the suitability of the industrial technology available in the centre for Advanced Digital Manufacturing Technology and the clinical biomechanics
movement analysis laboratory for exoskeleton development and;
2. Propose a state-of-the-art sensor network and control architecture technologies and configurations to be used in a powered exoskeletal foot ankle orthesis.
Investigating the compatibility of technologies to be used for wearable robots
Proposed Future Work
This study has assessed the feasibility of transferring real time
technology from industrial robotics into the exoskeleton domain.
Industrial technology available in the centre for Advanced Digital
Manufacturing was found to be too bulky for a wearable robotic
device. LabVIEW has turned out to be an intuitive and
appropriate programming language. A state-of-the-art sensor
network and control architecture technologies and configurations
to be used in a powered exoskeletal foot ankle orthesis have been
proposed for further development and testing. A final decision on
the particular components to use has not been made yet.
Figure 1: HAL-5
(Hybrid Assistive
Limb) Exoskeleton.
Exoskeleton for both
power augmentation
and rehabilitation
purposes developed
at the University of
Tsukuba, Japan (Herr,
2009).
Figure 3: Sensor networkwith the Whittle’s Gait cycle
from adapted from Levine et al. (2012)
Figure 4: Proposed Real time distributed hardware
control architecture adapted from Park et al. (2011)
The proposed wearable technology
will comprise of a measurement,
instrumentation and control
network including 3D inertial
motion units (IMUs) on the foot and
The data acquisition modules are Inertial
Measurement Units (IMU) and pressure
sensors along with the conditioning
circuitry. The IMUs and pressure sensor
have a dedicated microcontroller (µC) for
signal processing. The ankle joint angles
will be calculated in real time using the
General IMU µC. The processed data e
will be transmitted to the Core controller
which will perform the control. The Core
controller will command the actuation
providing feedback to the system. The
hardware control architecture is intended
to be distributed and highly modular
with an EtherCAT based communication
network with low-latency high
bandwidth real-time communication.
lower leg segment capable of
measuring ankle pronation.
Underneath the foot will be an
arrangement of pressure sensors.
NI Compact RIO was successfully
tested and evaluated for our
application. Its industrial real-time
software (LabVIEW Real-Time) and
architecture present characteristics
that make it suitable for modularity
and intuitive programing although it
is too bulky.
The specific IMUs, pressure sensors, local and main
microcontrollers should be selected. EtherCAT is a
suitable communication network but further
feasibility and comparative study on the other
Ehternet variations like Powerlink (EPL), Profinet-
IRT could be performed. A selection between
electric or fluid driven actuators should be
performed which will have a essential impact on
the power supply choice. LabVIEW should be
tested in the selected microcontrollers.
• The must requirements that applied to the
communication network were real-time capability,
accuracy, reliability and easy to implementation.
Feature a latency equal or less than 20 µs and
reducing cabling and at least 62.4 Mbit/s
bandwidth.
Figure 2: Ankle joint
angle variation in a
normal gait
cycle(Richards,2008)
• Typical ankle joint data during walking was
experimental results published in the literature
(Richards,2008).Ankle real data was also
gathered in the UCLAN human movement
laboratory to become familiar with the data
acquisition process. This was used to consider
instrumentation and event marks for a powered
exoskeletal foot ankle orthosis.
• The Must, Should, Could, Will-not (MoSCoW)
prioritisation method described by Hatton (2008)
has been applied to compare the requirements of
technology. The MoSCoW requirements have been
assigned using literature and calculations.
• The must requirements for the instrumentation
and control architecture are flexibility, modularity,
low cost, accessible software, deterministic,
compatible with bio-inspired control routines and
reasonable size and weight.
• Work was performed on a real European Regional
Development Fund (ERDF), ADMT Digital
Integrated Manufacturing Execution (DigitME)
project on real-time noise isolation. This allowed us
to assess the latest industrial instrumentation and
control equipment and software(NI Compact RIO
and LabVIEW real-time) for its utilisation in
wearable robotics.
Figure 5: Compact RIO tests set up
configuration