Special Issue Article
Advances in Mechanical Engineering
1–8
Ó The Author(s) 2015
DOI: 10.1177/1687814015575979
aime.sagepub.com
Identification of motion trend of lower
limbs based on near-infrared
spectroscopic technology
Chunguang Li
1
, Tao Chen
1
, Wei Qu
2
and Lining Sun
1
Abstract
To increase intelligence of walki ng-assiste d devices, it is important to ide ntify m otion mo de of the subject who wears
a walking-assisted device. In this paper, cerebral hemoglobin information was used for recognizing motion mode.
Spontaneous upstairs, downstairs, sit-down, and standup movements were performed on seven subjects. During the
movement, cerebral hemoglobin information was recorded by applying near-infrared spectroscopic technology.
Analyses of variance were performed to compare the rate of change of oxygenated hemoglobin and deoxygenated
hemoglobin (oxyHb_rate and deoxyHb_rate) in different motion modes and in different motor-related regions. In
PMCR region, oxyHb_rate and deoxyHb_rate were significantly different in the upstairs and downstairs modes
(p = 0.001 and p = 0.000); h owever, they were not obviously different in the sit-down and standup modes (p = 0.914
and p = 0.836). In PMCL region, oxyHb_rate and deoxyHb_rate were significantly different in the downstairs mode
(p = 0.008), whereas they were not distinctly different in the upstairs mode (p = 0.601). Results demonstrated t hat
the motion trend of two lower limbs could be identified based on the statistical difference between oxyHb_rate and
deoxyHb_rate in the PMCR region. As for cycle-repetitive movement of two lower limbs, upward and downward
motion direction could be furt her recognized based on the difference between oxyHb_ rat e and deoxyHb_r ate in
the PMCL region. Since the data using for analyses was those col lected before the star t of movement, the results will
be preferable to provide appropriate reference movements for a walking-assisted device. This is helpful to enhance
intelligence of walking-assisted devices.
Keywords
Mirror-symmetric movement, cycle-repetitive movement, identification of motion mode, oxyHb_rate and deoxyHb_rate
Date received: 22 September 2014; accepted: 19 January 2015
Academic Editor: Zhuming Bi
Introduction
Recently, the number of persons with motor dysfunc-
tion in lower limbs has been increasing markedly
because of natural disasters, injuries, accidents, dis-
eases, and so on. In order to restore patients’ ability of
independent walking, there is an urgent demand for
intelligent walking-assisted devices. This requires
walking-assisted devices to provide auxiliary power in
different motion modes and to determine motion mode
based on patients’ physiological information rather
than an oral command or once selection of buttons. To
control the movement of a device by using brain
1
Robotics and Microsystems Center, Soochow University, Suzhou, China
2
ECOVACS Robotics (Suzhou) Co., Ltd, Suzhou, China
Corresponding author:
Tao Chen, Robotics and Microsystems Center, Soochow University,
Suzhou 215021, China.
Email: chent@suda.edu.cn
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