Abstract

This paper illustrates the development and experimental validation of a robotic ankle–foot orthosis (AFO) with a series elastic actuator (SEA) and a magneto-rheological (MR) brake. First, the biomechanics of a human ankle joint during walking is explained. Next, the hardware design of the robotic AFO is introduced, including its mechanical structure, actuator design and configuration, and electronic system. The SEA is primarily composed of an electric motor, a planetary gearbox, a torsion spring, and a pair of bevel gears. The MR brake can modulate the viscosity of the robotic AFO and generate a large braking torque of 21.8 Nm with a low power of 8.8 W. Additionally, the modeling of the robotic AFO is presented, followed by an introduction to its control; several gait evaluation indices are proposed as well. Finally, a pilot study is conducted to verify the effectiveness of the developed robotic AFO. The experimental results demonstrate that the robotic AFO has the potential to provide dorsiflexion assistance, thus preventing foot slap and toe drag, in addition to plantarflexion assistance for the forward propulsion of the body. During a gait cycle, an average power of 0.23 W is harvested, and an 8% improvement in the system energy efficiency is achieved.

References

References
1.
Langhorne
,
P.
,
Bernhardt
,
J.
, and
Kwakkel
,
G.
,
2011
, “
Stroke Rehabilitation
,”
Lancet
,
377
(
9778
), pp.
1693
1702
. 10.1016/S0140-6736(11)60325-5
2.
Winter
,
D. A.
,
1991
,
Biomechanics and Motor Control of Human Gait: Normal, Elderly and Pathological
,
University of Waterloo Press
,
Waterloo, ON
.
3.
Chen
,
G.
,
Patten
,
C.
,
Kothari
,
D. H.
, and
Zajac
,
F. E.
,
2005
, “
Gait Differences Between Individuals With Post-Stroke Hemiparesis and Non-disabled Controls at Matched Speeds
,”
Gait Posture
,
22
(
1
), pp.
51
56
. 10.1016/j.gaitpost.2004.06.009
4.
Stoquart
,
G.
,
Detrembleur
,
C.
, and
Lejeune
,
T. M.
,
2012
, “
The Reasons Why Stroke Patients Expend So Much Energy to Walk Slowly
,”
Gait Posture
,
36
(
3
), pp.
409
413
. 10.1016/j.gaitpost.2012.03.019
5.
Neptune
,
R. R.
,
Kautz
,
S. A.
, and
Zajac
,
F. E.
,
2001
, “
Contributions of the Individual Ankle Plantar Fexors to Support, Forward Progression and Swing Initiation During Walking
,”
J. Biomech.
,
34
(
11
), pp.
1387
1398
. 10.1016/S0021-9290(01)00105-1
6.
Bulley
,
C.
,
Mercer
,
T. H.
,
Hooper
,
J. E.
,
Cowan
,
P.
,
Scott
,
S.
, and
van der Linden
,
M. L.
,
2014
, “
Experiences of Functional Electrical Stimulation (FES) and Ankle Foot Orthoses (AFOs) for Foot-Drop in People With Multiple Sclerosis
,”
Disability Rehabil. Assistive Technol.
,
10
(
6
), pp.
458
467
. 10.3109/17483107.2014.913713
7.
Bregman
,
D. J.
,
Harlaar
,
J.
,
Meskers
,
C. G.
, and
de Groot
,
V.
,
2012
, “
Spring-Like Ankle Foot Orthoses Reduce the Energy Cost of Walking by Taking Over Ankle Work
,”
Gait Posture
,
35
(
1
), pp.
148
153
. 10.1016/j.gaitpost.2011.08.026
8.
Wang
,
C. Z.
,
Fang
,
Y. F.
,
Guo
,
S.
, and
Chen
,
Y. Q.
,
2013
, “
Design and Kinematical Performance Analysis of a 3-RUS/RRR Redundantly Actuated Parallel Mechanism for Ankle Rehabilitation
,”
ASME J. Mech. Rob.
,
5
(
4
), p.
041003
. 10.1115/1.4024736
9.
Nurahmi
,
L.
,
Caro
,
S.
, and
Solichin
,
M.
,
2019
, “
A Novel Ankle Rehabilitation Device Based on a Reconfigurable 3-RPS Parallel Manipulator
,”
Mech. Mach. Theory
,
134
, pp.
135
150
. 10.1016/j.mechmachtheory.2018.12.017
10.
Gasparri
,
G. M.
,
Luque
,
J.
, and
Lerner
,
Z. F.
,
2019
, “
Proportional Joint-Moment Control for Instantaneously Adaptive Ankle Exoskeleton Assistance
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
27
(
4
), pp.
751
759
. 10.1109/TNSRE.2019.2905979
11.
Yandell
,
M. B.
,
Tacca
,
J. R.
, and
Zelik
,
K. E.
,
2019
, “
Design of a Low Profile, Unpowered Ankle Exoskeleton That Fits Under Clothes: Overcoming Practical Barriers to Widespread Societal Adoption
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
27
(
4
), pp.
712
723
. 10.1109/TNSRE.2019.2904924
12.
Yamamoto
,
S.
,
Ebina
,
M.
,
Iwasaki
,
M.
,
Kubo
,
S.
,
Kawai
,
H.
, and
Hayashi
,
T.
,
1993
, “
Comparative Study of Characteristics of Plastic AFOs
,”
J. Prosthet. Orthot.
,
5
(
2
), pp.
59/47
52/64
.
13.
Daryabor
,
A.
,
Arazpour
,
M.
, and
Aminian
,
G.
,
2018
, “
Effect of Different Designs of Ankle-Foot Orthoses on Gait in Patients With Stroke: A Systematic Review
,”
Gait Posture
,
62
, pp.
268
279
. 10.1016/j.gaitpost.2018.03.026
14.
Oba
,
T.
,
Kadone
,
H.
,
Hassan
,
M.
, and
Suzuki
,
K.
,
2019
, “
Robotic Ankle-Foot Orthosis With a Variable Viscosity Link Using MR Fluid
,”
IEEE/ASME Trans. Mechatron.
,
24
(
2
), pp.
495
504
. 10.1109/TMECH.2019.2894406
15.
Sedlacik
,
M.
,
Pavlínek
,
V.
,
Vyroubal
,
R.
,
Peer
,
P.
, and
Filip
,
P.
,
2013
, “
A Dimorphic Magnetorheological Fluid With Improved Oxidation and Chemical Stability Under Oscillatory Shear
,”
Smart Mater. Struct.
,
22
(
3
), p.
035013
. 10.1088/0964-1726/22/3/035011
16.
Chen J
,
Z.
, and
Liao W
,
H.
,
2010
, “
Design, Testing and Control of a Magnetorheological Actuator for Assistive Knee Braces
,”
Smart Mater. Struct.
,
19
(
3
), p.
035029
. 10.1088/0964-1726/19/3/035029
17.
Gao
,
F.
,
Liu Y
,
N.
, and
Liao W
,
H.
,
2017
, “
Optimal Design of a Magnetorheological Damper Used in Smart Prosthetic Knees
,”
Smart Mater. Struct.
,
26
(
3
), p.
035034
. 10.1088/1361-665X/aa5494
18.
Furusho
,
J.
,
Kikuchi
,
T.
,
Tokuda
,
M.
,
Kakehashi
,
T.
,
Ikeda
,
K.
,
Morimoto
,
S.
,
Hashimoto
,
Y.
,
Tomiyama
,
H.
,
Nakagawa
,
A.
, and
Akazawa
,
Y.
,
2007
, “
Development of Shear Type Compact MR Brake for the Intelligent Ankle-Foot Orthosis and its Control
,”
Proceedings of IEEE International Conference Rehabilitation Robotics
,
Noordwijk, The Netherlands
,
June 12–15
, pp.
89
94
.
19.
Naito
,
H.
,
Akazawa
,
Y.
,
Tagaya
,
K.
,
Matsumoto
,
T.
, and
Tanaka
,
M.
,
2009
, “
An Ankle-Foot-Orthosis With a Variable-Resistance Ankle Joint Using a Magnetorheological-Fluid Rotary Damper
,”
J. Biomech. Sci. Eng.
,
4
(
2
), pp.
182
191
. 10.1299/jbse.4.182
20.
Yamamoto
,
S.
,
Ibayashi
,
S.
,
Fuchi
,
M.
, and
Yasui
,
T.
,
2015
, “
Immediate-Term Effects of Use of an Ankle-Foot Orthosis With an Oil Damper on the Gait of Stroke Patients When Walking Without the Device
,”
Prosthet. Orthot. Int.
,
39
(
2
), pp.
140
149
. 10.1177/0309364613518340
21.
Shafiei
,
M.
, and
Behzadipour
,
S.
,
2020
, “
The Effects of the Connection Stiffness of Robotic Exoskeletons on the Gait Quality and Comfort
,”
ASME J. Mech. Rob.
,
12
(
1
), p.
011007
. 10.1115/1.4044841
22.
Font-Llagunes
,
J. M.
,
Lugrıs
,
U.
,
Clos
,
D.
,
Alonso
,
F. J.
, and
Cuadrado
,
J.
,
2020
, “
Design, Control, and Pilot Study of a Lightweight and Modular Robotic Exoskeleton for Walking Assistance After Spinal Cord Injury
,”
ASME J. Mech. Rob.
,
12
(
3
), p.
031008
. 10.1115/1.4045510
23.
Chen
,
B.
,
Zi
,
B.
,
Wang
,
Z. Y.
,
Qin
,
L.
, and
Liao
,
W. H.
,
2019
, “
Knee Exoskeletons for Gait Rehabilitation and Human Performance Augmentation: A State-of-the-Art
,”
Mech. Mach. Theory
,
134
, pp.
499
511
. 10.1016/j.mechmachtheory.2019.01.016
24.
Takahashi
,
K. Z.
,
Lewek
,
M. D.
, and
Sawicki
,
G. S.
,
2015
, “
A Neuromechanics-Based Powered Ankle Exoskeleton to Assist Walking Post-Stroke: A Feasibility Study
,”
J. Neuroeng. Rehabil.
,
12
(
1
), pp.
23
35
. 10.1186/s12984-015-0015-7
25.
Liu
,
J. Z.
,
Xiong
,
C. H.
, and
Fu
,
C. L.
,
2019
, “
An Ankle Exoskeleton Using a Lightweight Motor to Create High Power Assistance for Push-Off
,”
ASME J. Mech. Rob.
,
11
(
4
), p.
041001
. 10.1115/1.4043456
26.
Lerner
,
Z. F.
,
Gasparri
,
G. M.
,
Bair
,
M. O.
,
Lawson
,
J. L.
,
Luque
,
J.
,
Harvey
,
T. A.
, and
Lerner
,
A. T.
,
2018
, “
An Untethered Ankle Exoskeleton Improves Walking Economy in a Pilot Study of Individuals With Cerebral Palsy
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
26
(
10
), pp.
1985
1993
. 10.1109/TNSRE.2018.2870756
27.
Ward
,
J.
,
Boehler
,
A.
, and
Louis
,
S.
,
2011
, “
Stroke Survivors’ Gait Adaptations to a Powered Ankle Foot Orthosis
,”
Adv. Robot.
,
25
(
15
), pp.
1879
1901
. 10.1163/016918611X588907
28.
Yeung
,
L. F.
,
Ockenfeld
,
C.
,
Pang
,
M. K.
,
Wai
,
H. W.
,
Soo
,
O. Y.
,
Li
,
S. W.
, and
Tong
,
K. Y.
,
2018
, “
Randomized Controlled Trial of Robot-Assisted Gait Training With Dorsiflexion Assistance on Chronic Stroke Patients Wearing Ankle-Foot-Orthosis
,”
J. Neuroeng. Rehabil.
,
15
(
51
), pp.
1
12
.
29.
Chen
,
B.
,
Zi
,
B.
,
Zeng
,
Y. S.
,
Qin
,
L.
, and
Liao
,
W. H.
,
2018
, “
Ankle-Foot Orthoses for Rehabilitation and Reducing Metabolic Cost of Walking: Possibilities and Challenges
,”
Mechatronics
,
53
, pp.
241
250
. 10.1016/j.mechatronics.2018.06.014
30.
Shorter
,
K. A.
,
Kogler
,
G. F.
,
Loth
,
E.
,
Durfee
,
W. K.
, and
Hsiao-Wecksler
,
E. T.
,
2011
, “
A Portable Powered Ankle-Foot Orthosis for Rehabilitation
,”
J. Rehabil. Res. Dev.
,
48
(
4
), pp.
459
472
. 10.1682/JRRD.2010.04.0054
31.
Yeung
,
L. F.
,
Ockenfeld
,
C.
,
Pang
,
M. K.
,
Wai
,
H. W.
,
Soo
,
O. Y.
,
Li
,
S. W.
, and
Tong
,
K. Y.
,
2017
, “
Design of an Exoskeleton Ankle Robot for Robot-Assisted Gait Training of Stroke Patients
,”
Proceedings of IEEE International Conference on Rehabilitation Robotics
,
London
,
July 17–20
, pp.
211
215
.
32.
Choi
,
H.
,
Park
,
Y. J.
,
Seo
,
K.
,
Lee
,
J.
,
Lee
,
S.
, and
Shim
,
Y.
,
2018
, “
A Multi-Functional Ankle Exoskeleton for Mobility Enhancement of Gait-Impaired Individuals and Seniors
,”
IEEE Robot. Autom. Lett.
,
3
(
1
), pp.
411
418
. 10.1109/LRA.2017.2734239
33.
Ferris
,
D. P.
,
Czerniecki
,
J. M.
, and
Hannaford
,
B.
,
2005
, “
An Ankle-Foot Orthosis Powered by Artificial Pneumatic Muscles
,”
J. Appl. Biomech.
,
21
(
2
), pp.
189
197
. 10.1123/jab.21.2.189
34.
Aguilar-Sierra
,
H.
,
Yu
,
W.
,
Salazar
,
S.
, and
Lopez
,
R.
,
2015
, “
Design and Control of Hybrid Actuation Lower Limb Exoskeleton
,”
Adv. Mech. Eng.
,
7
(
6
), pp.
1
13
. 10.1177/1687814015590988
35.
Refour
,
E. M.
,
Sebastian
,
B.
,
Chauhan
,
R. J.
, and
Ben-Tzvi
,
P.
,
2019
, “
A General Purpose Robotic Hand Exoskeleton With Series Elastic Actuation
,”
ASME J. Mech. Rob.
,
11
(
6
), p.
060902
. 10.1115/1.4044543
36.
Manna
,
S. K.
, and
Dubey
,
V. N.
,
2019
, “
A Portable Elbow Exoskeleton for Three Stages of Rehabilitation
,”
ASME J. Mech. Rob.
,
11
(
6
), p.
065002
. 10.1115/1.4044535
37.
Agboola-Dobson
,
A.
,
Wei
,
G. W.
, and
Ren
,
L.
,
2019
, “
Biologically Inspired Design and Development of a Variable Stiffness Powered Ankle-Foot Prosthesis
,”
ASME J. Mech. Rob.
,
11
(
4
), p.
041012
. 10.1115/1.4043603
38.
Dijk
,
W. V.
,
Meijneke
,
C.
, and
Kooij
,
H. V. D.
,
2017
, “
Evaluation of the Achilles Ankle Exoskeleton
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
25
(
2
), pp.
151
160
. 10.1109/TNSRE.2016.2527780
39.
Boehler
,
A. W.
,
Hollander
,
K. W.
,
Sugar
,
T. G.
, and
Shin
,
D.
,
2008
, “
Design, Implementation and Test Results of a Robust Control Method for a Powered Ankle Foot Orthosis (AFO)
,”
Proceedings of IEEE International Conference on Robotics and Automation
,
Pasadena, CA
,
May 19–23
, pp.
2025
2030
.
40.
Erdogan
,
A.
,
Celebi
,
B.
,
Satici
,
A. C.
, and
Patoglu Patoglu
,
V.
,
2017
, “
Assist On-Ankle: A Reconfigurable Ankle Exoskeleton With Series-Elastic Actuation
,”
Auton Robot.
,
41
, pp.
743
758
.
41.
Blaya
,
J. A.
, and
Herr
,
H.
,
2004
, “
Adaptive Control of a Variable-Impedance Ankle-Foot Orthosis to Assist Drop-Foot Gait
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
12
(
1
), pp.
24
31
. 10.1109/TNSRE.2003.823266
42.
Zinn
,
M.
,
Khatib
,
O.
,
Roth
,
B.
, and
Salisbury
,
J. K.
,
2004
, “
Playing It Safe [Human-Friendly Robots]
,”
IEEE Robot. Autom. Mag.
,
11
(
2
), pp.
12
21
. 10.1109/MRA.2004.1310938
43.
Wang
,
Z.
,
Yip
,
H. M.
,
Navarro-Alarcon
,
D.
,
Li
,
P.
,
Liu
,
Y. H.
,
Sun
,
D.
,
Wang
,
H. S.
, and
Cheung
,
T. H.
,
2016
, “
Design of a Novel Compliant Safe Robot Joint With Multiple Working States
,”
IEEE/ASME Trans. Mechatron.
,
21
(
2
), pp.
1193
1198
. 10.1109/TMECH.2015.2500602
44.
Moltedo
,
M.
,
Cavallo
,
G.
,
Baček
,
T.
,
Lataire
,
J.
,
Vanderborght
,
B.
,
Lefeber
,
D.
, and
Rodriguez-Guerrero
,
C.
,
2019
, “
Variable Stiffness Ankle Actuator for Use in Robotic-Assisted Walking: Control Strategy and Experimental Characterization
,”
Mech. Mach. Theory
,
134
, pp.
604
624
. 10.1016/j.mechmachtheory.2019.01.017
45.
Rahman
,
S. M. M.
, and
Ikeura
,
R.
,
2012
, “
A Novel Variable Impedance Compact Compliant Ankle Robot for Overground Gait Rehabilitation and Assistance
,”
Procedia Eng.
,
41
, pp.
522
531
. 10.1016/j.proeng.2012.07.207
46.
Inman
,
V. T.
,
Ralston
,
H. J.
, and
Todd
,
F.
,
1981
, “Human Locomotion,”
Human Walking
,
J.
Rose
, and
J. G.
Gamble
, eds.,
Williams and Wilkins
,
Baltimore, CA
.
47.
Zhou
,
X.
, and
Fang
,
J.
,
2013
, “
Precise Braking Torque Control for Attitude Control flywheel With Small Inductance Brushless DC Motor
,”
IEEE Trans. Power Electron.
,
28
(
11
), pp.
5380
5390
. 10.1109/TPEL.2013.2244617
48.
Engelhart
,
D.
,
Schouten
,
A. C.
,
Aarts
,
R. G. K. M.
, and
van der Kooij
,
H.
,
2015
, “
Assessment of Multi-Joint Coordination and Adaptation in Standing Balance: A Novel Device and System Identification Technique
,”
IEEE Trans. Neural Syst. Rehabil. Eng.
,
23
(
6
), pp.
973
982
.
49.
Fitzpatrick
,
R. C.
,
Taylor
,
J. L.
, and
McCloskey
,
D. I.
,
1992
, “
Ankle Stiffness of Standing Humans in Response to Imperceptible Perturbation: Reflex and Task-Dependent Components
,”
J. Physiol.
,
454
(
1
), pp.
533
547
. 10.1113/jphysiol.1992.sp019278
50.
Pons
,
J. L.
,
2008
,
Wearable Robots: Biomechatronic Exoskeletons
,
John Wiley & Sons, Inc.
,
Hoboken, NJ
, pp.
47
85
.
51.
Shamaei
,
K.
,
Cenciarini
,
M.
, and
Dollar
,
A. M.
,
2011
, “
On the Mechanics of the Ankle in the Stance Phase of the Gait
,”
Proceedings of IEEE International Conference on Engineering in Medicine and Biology Society
,
Boston, MA
,
Aug. 30–Sept. 3
, pp.
8135
8140
.
52.
Kirtley
C
, CGA Normative Gait Database, Hong Kong Polytechnic University, http://www.clinicalgaitanalysis.com/data/, Accessed March 8, 2020.
53.
Ishikawa
,
M.
,
Komi
,
P. V.
,
Grey
,
M. J.
,
Lepola
,
V.
, and
Bruggemann
,
G. P.
,
2005
, “
Muscle-Tendon Interaction and Elastic Energy Usage in Human Walking
,”
J. Appl. Physiol.
,
99
(
2
), pp.
603
608
. 10.1152/japplphysiol.00189.2005
54.
van den Bogert
,
A. J.
,
2003
, “
Exotendons for Assistance of Human Locomotion
,”
BioMedical Eng.
,
2
(
17
), pp.
1
8
.
55.
Hassan
,
M.
,
Yagi
,
K.
,
Kadone
,
H.
,
Ueno
,
T.
,
Mochiyama
,
H.
, and
Suzuki
,
K.
,
2019
, “
Optimized Design of a Variable Viscosity Link for Robotic AFO
,”
Proceedings of IEEE International Conference on. Engineering in Medicine and. Biology Society
,
Berlin, Germany
,
July 23–27
, pp.
6220
6223
.
56.
Kikuchi
,
T.
,
Tanida
,
S.
,
Otsuki
,
K.
,
Yasuda
,
T.
, and
Furusho
,
J.
,
2010
, “
Development of Third-Generation Intelligently Controllable Ankle-Foot Orthosis with Compact MR Fluid Brake
,”
Proceedings of IEEE International Conference on Robotics and Automation
,
Anchorage, AK
,
May 3–8
, pp.
2209
2214
.
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