An Artificial Neural Network for Hand Movement Classification using
Surface Electromyography
Paulo L. Viana
1
, Victoria S. Fujii
1
, Larissa M. Lima
1
, Gabriel L. Ouriques
1
, Gustavo C. Oliveira
2
,
Renato Varoto
3
and Alberto Cliquet Jr.
1,2,3
1
Department of Electrical and Computer Engineering, Trabalhador S
˜
ao-Carlense Avenue, 400, S
˜
ao Carlos, Brazil
2
University of S
˜
ao Paulo Interunits Graduate Program in Bioengineering, University of S
˜
ao Paulo,
Trabalhador S
˜
ao-Carlense Avenue, 400, S
˜
ao Carlos, Brazil
3
Department of Orthopedics and Traumatology, University of Campinas, Cidade Universit
´
aria Zeferino Vaz,
Campinas, Brazil
Keywords:
Neural Networks, Hand Movement, Electromyography, Rehabilitation, Machine Learning.
Abstract:
In this paper we present the development of an artificial neural network that uses surface EMG data from two
forearm muscles to classify hand movements and gestures. We trained our network to classify three different
sets of movements, using EMG data from six healthy subjects. We were able to achieve hit rates of above 99%
in the training sets and hit rates of above 85% in all three test sets, with a maximum of 88.8% for the second
movement set. Advantages of the proposed method include small number of electrodes, reduced complexity,
computational cost and response time.
1 INTRODUCTION
For healthy individuals, the execution of daily tasks
(e.g feeding, bathing and dressing, for example) heav-
ily relies on the adequate motor control of the upper
limbs, which is performed by the central and periph-
eral nervous system. Unfortunately, there are many
pathological conditions that can impair one’s ability
to control his or her own arms and hands, such as
spinal cord lesions, stroke and cerebral palsy. Experi-
encing one of these conditions can lead to a reduced
sense of autonomy and negatively impact one’s qual-
ity of life (Guyton, 2010).
Many strategies have been employed over the
years to help individuals cope with reduced upper
limb motor control. One of these approaches is the
use of myoelectric controlled prosthesis, which began
to have a significant role in the rehabilitation of up-
per limb deficient patients in the 1970s. This type of
prosthesis makes use of the myoelectric signal, also
known as EMG, which is a group of electrical signals
that is generated by the body and precede mechanical
muscle activity. Its amplitude is small (1.5 mV RMS)
and random, and its frequency can range from 6 to
500 Hz, with most of its energy comprised between
20 to 150 Hz. These signals can be captured directly
from the skin, using surface electrodes, or from the
muscles, using needle electrodes (Englehart and Hud-
gins, 2003).
Myoelectric controlled prosthesis offer many ad-
vantages over other types. Firstly, the signal can be
acquired in a non-invasive manner, reducing risks for
the user. Secondly, small effort and muscle activity
is necessary to generate the control signals. Thir-
dle, its controller is relatively easy to adapt. Lastly,
there is no need for straps and harnesses that are re-
quired when using mechanical switch and body pow-
ered control (Englehart and Hudgins, 2003).
Although many myoelectric control systems are
currently available and have gained some success,
their application is relatively limited in the control
of multiple functions and devices. This is unfortu-
nate, since the capacity to offer multiple functions and
accurate movement selection is a critical feature that
could highly increase the functional benefits of pros-
thetic apparatuses (Englehart and Hudgins, 2003).
Exploring this context, many researchers have
developed strategies for a pattern-recognition-based
myoelectric control, which could be used to link de-
grees of freedom of the prosthetic apparatus to move-
ment classes. For small groups of movements, these
approaches have been successful. However, error
rates tend to increase with the number of movements
analyzed. For example, Glette et al. (2008) applied
a variety of machine learning techniques, such as k-
nearest neighbors, decision trees and support vector
machines, to identify 8 different movements using
surface EMG signals. Error rates of their classifiers
Viana, P., Fujii, V., Lima, L., Ouriques, G., Oliveira, G., Varoto, R. and Cliquet Jr., A.
An Artificial Neural Network for Hand Movement Classification using Surface Electromyography.
DOI: 10.5220/0007404201850192
In Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2019), pages 185-192
ISBN: 978-989-758-353-7
Copyright
c
2019 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
185