Design and development of the sEMG-based exoskeleton strength enhancer for the legs

Mikecon Cenit, Vaibhav Gandhi


This paper reviews the different exoskeleton designs and presents a working prototype of a surface electromyography (EMG) controlled exoskeleton to enhance the strength of the lower leg. The Computer Aided Design (CAD) model of the exoskeleton is designed, 3D printed with respect to the golden ratio of human anthropometry, and tested structurally. The exoskeleton control system is designed on the LabVIEW National Instrument platform and embedded in myRIO. Surface EMG sensors (sEMG) and flex sensors are used coherently to create different state filters for the EMG, human body posture and control for the mechanical exoskeleton actuation. The myRIO is used to process sEMG signals and send control signals to the exoskeleton. Thus, the complete exoskeleton system consists of sEMG as primary sensor and flex sensor as secondary sensor while the whole control system is designed in LabVIEW. FEA simulation and tests show that the exoskeleton is suitable for an average human weight of 62 kg plus excess force with different reactive spring forces. However, due to the mechanical properties of the exoskeleton actuator, it will require additional lift to provide the rapid reactive impulse force needed to increase biomechanical movement such as squatting up. Finally, with the increasing availability of such assistive devices on the market, the important aspect of ethical, social and legal issues have also emerged and discussed in this paper.


leg-exoskeleton; electromyography based exoskeleton; LabVIEW myRIO; ethical, societal, and legal concerns.

Full Text:



H. S. Lo and S. Q. Xie, "Exoskeleton robots for upper-limb rehabilitation: State of the art and future prospects," Med. Eng. Phys., vol. 34, (3), pp. 261-268, 2012.

A. B. Zoss, H. Kazerooni and A. Chu, "Biomechanical design of the Berkeley lower extremity exoskeleton (BLEEX)," IEEE/ASME Transactions on Mechatronics, vol. 11, (2), pp. 128-138, 2006.

M. Hanlon, "Raytheon XOS 2: Second-Generation Exoskeleton. Robotics Suit, United States of America," Gizmag: Website:www.Gizmag.Com/Raytheon-significantly-Progresses-Exoskeletondesign/16479, (Дата Обращения 28.01.2015), 2015.

K. Tsuneyasu, A. Ohno, Y. Fukuda, K. Ogawa, T. Tsuji and Y. Kurita, "A soft exoskeleton suit to reduce muscle fatigue with pneumatic artificial muscles," in Proceedings of the 9th Augmented Human International Conference, 2018.

A. T. Asbeck, R. J. Dyer, A. F. Larusson and C. J. Walsh, "Biologically-inspired soft exosuit," in 2013 IEEE 13th International Conference on Rehabilitation Robotics (ICORR), 2013.

C. Walsh, A. T. Asbeck, I. G. Bujanda, Y. Ding, R. J. Dyer, A. F. Larusson, B. T. Quinlivan, K. Schmidt, D. Wagner and M. Wehner, "Soft Exosuit for Assistance with Human Motion," 2016.

L. Brenner, "Exploring the psychosocial impact of Ekso Bionics Technology," Arch. Phys. Med. Rehabil., vol. 97, (10), pp. e113, 2016.

C. M. Wilkins, "An Experimental Study of the Human Interface with One Atmosphere Diving Suit by Appendages," 2016.

A. S. Gorgey, "Robotic exoskeletons: The current pros and cons," World Journal of Orthopedics, vol. 9, (9), pp. 112, 2018.

M. Mekki, A. D. Delgado, A. Fry, D. Putrino and V. Huang, "Robotic rehabilitation and spinal cord injury: a narrative review," Neurotherapeutics, vol. 15, (3), pp. 604-617, 2018.

M. Fontana, R. Vertechy, S. Marcheschi, F. Salsedo and M. Bergamasco, "The body extender: A full-body exoskeleton for the transport and handling of heavy loads," IEEE Robotics & Automation Magazine, vol. 21, (4), pp. 34-44, 2014.

W. Van Diik, T. Van de Wijdeven, M. M. Holscher, R. Barents, R. Könemann, F. Krause and C. L. Koerhuis, "Exobuddy-A non-anthropomorphic quasi-passive exoskeleton for load carrying assistance," in 2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob), 2018.

F. Lunardini, C. Casellato, A. d'Avella, T. D. Sanger and A. Pedrocchi, "Robustness and reliability of synergy-based myocontrol of a multiple degree of freedom robotic arm," IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 24, (9), pp. 940-950, 2015.

R. Bogue, "Exoskeletons and robotic prosthetics: a review of recent developments," Industrial Robot: An International Journal, 2009.

N. Fotion and G. Elfstrom, "Military ethics: guidelines for peace and war," 1986.

M. Vukobratovic et al, Biped Locomotion: Dynamics, Stability, Control and Application. Springer Science & Business Media, vol. 7, 2012.

M. K. Reed, "LIFESUIT exoskeleton gives the gift of walking so they shall walk," in IEEE Global Humanitarian Technology Conference (GHTC 2014), 2014.

C. Kopp, "Exoskeletons for warriors of the future," Defence Today, vol. 9, (2), pp. 38-40, 2011.

S. Hesse, H. Schmidt, C. Werner and A. Bardeleben, "Upper and lower extremity robotic devices for rehabilitation and for studying motor control," Curr. Opin. Neurol., vol. 16, (6), pp. 705-710, 2003.

K. Bharadwaj, T. G. Sugar, J. B. Koeneman and E. J. Koeneman, "Design of a robotic gait trainer using spring over muscle actuators for ankle stroke rehabilitation," 2005.

C. T. Freeman, E. Rogers, A. Hughes, J. H. Burridge and K. L. Meadmore, "Iterative learning control in health care: Electrical stimulation and robotic-assisted upper-limb stroke rehabilitation," IEEE Control Syst. Mag., vol. 32, (1), pp. 18-43, 2012.

L. Lucas, M. DiCicco and Y. Matsuoka, "An EMG-controlled hand exoskeleton for natural pinching," Journal of Robotics and Mechatronics, vol. 16, pp. 482-488, 2004.

M. Krawczyk, Z. Yang, V. Gandhi, M. Karamanoglu, F. M. Franca, L. Priscila, W. Xiaochen and T. Geng, "Wrist movement detector for ROS based control of the robotic hand," Advances in Robotics and Automation, vol. 7, (1), 2018.

T. Nef, M. Guidali and R. Riener, "ARMin III–arm therapy exoskeleton with an ergonomic shoulder actuation," Applied Bionics and Biomechanics, vol. 6, (2), pp. 127-142, 2009.

A. H. Stienen, E. E. Hekman, Van Der Helm, Frans CT and H. Van Der Kooij, "Self-aligning exoskeleton axes through decoupling of joint rotations and translations," IEEE Transactions on Robotics, vol. 25, (3), pp. 628-633, 2009.

Y. Ren, H. Park and L. Zhang, "Developing a whole-arm exoskeleton robot with hand opening and closing mechanism for upper limb stroke rehabilitation," in 2009 IEEE International Conference on Rehabilitation Robotics, 2009.

C. Carignan, J. Tang and S. Roderick, "Development of an exoskeleton haptic interface for virtual task training," in 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009.

A. Roy, H. I. Krebs, S. L. Patterson, T. N. Judkins, I. Khanna, L. W. Forrester, R. M. Macko and N. Hogan, "Measurement of human ankle stiffness using the anklebot," in 2007 IEEE 10th International Conference on Rehabilitation Robotics, 2007.

J. Lu, K. Haninger, W. Chen, S. Gowda, M. Tomizuka and J. M. Carmena, "Design of a passive upper limb exoskeleton for macaque monkeys," Journal of Dynamic Systems, Measurement, and Control, vol. 138, (11), 2016.

S. Oh, E. Baek, S. Song, S. Mohammed, D. Jeon and K. Kong, "A generalized control framework of assistive controllers and its application to lower limb exoskeletons," Robotics and Autonomous Systems, vol. 73, pp. 68-77, 2015.

J. Zhu and H. Zhou, "Realization of key technology for intelligent exoskeleton load system," in Advances in Information Technology and Industry Applications, 2012.

D. M. Dao, P. D. Pham, T. X. Tran and T. T. T. Le, "Study on the transient response of lower limb rehabilitation actuator using the pneumatic cylinder," Journal of Mechatronics, Electrical Power, and Vehicular Technology, vol. 9, (2), pp. 65-72, 2018.

V. Krasin, V. Gandhi and Z. Yang, "EMG based elbow joint powered exoskeleton for biceps brachii strength augmentation," in July 12-17, 2015.

R. M. Singh, S. Chatterji and A. Kumar, "Trends and challenges in EMG based control scheme of exoskeleton robots-a review," Int J Sci Eng Res, vol. 3, (9), pp. 933-940, 2012.

L. J. Myers, M. Lowery, M. O'malley, C. L. Vaughan, C. Heneghan, A. S. C. Gibson, Y. Harley and R. Sreenivasan, "Rectification and non-linear pre-processing of EMG signals for cortico-muscular analysis," J. Neurosci. Methods, vol. 124, (2), pp. 157-165, 2003.

D. Copaci, D. Serrano, L. Moreno and D. Blanco, "A High-Level Control Algorithm Based on sEMG Signalling for an Elbow Joint SMA Exoskeleton," Sensors, vol. 18, (8), pp. 2522, 2018.

G. Weddell, B. Feinstein and R. E. Pattle, "The electrical activity of voluntary muscle in man under normal and pathological conditions." Brain: A Journal of Neurology, 1944.

D. Denny-Brown and J. B. Pennybacker, "Fibrillation and fasciculation in voluntary muscle," Brain, vol. 61, (3), pp. 311-312, 1938.

O. Fukuda, T. Tsuji, M. Kaneko and A. Otsuka, "A human-assisting manipulator teleoperated by EMG signals and arm motions," IEEE Trans. Rob. Autom., vol. 19, (2), pp. 210-222, 2003.

P. Konrad, "A Practical Introduction to Kinesiological Electromyography," The ABC of EMG, vol. 1, 2005.

C. J. De Luca, A. Adam, R. Wotiz, L. D. Gilmore and S. H. Nawab, "Decomposition of surface EMG signals," J. Neurophysiol., vol. 96, (3), pp. 1646-1657, 2006.

C. J. De Luca, S. Chang, S. H. Roy, J. C. Kline and S. H. Nawab, "Decomposition of surface EMG signals from cyclic dynamic contractions," J. Neurophysiol., vol. 113, (6), pp. 1941-1951, 2015.

F. Zaheer, S. H. Roy and C. J. De Luca, "Preferred sensor sites for surface EMG signal decomposition," Physiol. Meas., vol. 33, (2), pp. 195, 2012.

N. U. Ahamed, K. Sundaraj, R. B. Ahmad, M. Rahman and M. A. Islam, "Analysis of right arm biceps brachii muscle activity with varying the electrode placement on three male age groups during isometric contractions using a wireless EMG sensor," Procedia Engineering, vol. 41, pp. 61-67, 2012.

C. Amma, T. Krings, J. Böer and T. Schultz, "Advancing muscle-computer interfaces with high-density electromyography," in Proceedings of the 33rd Annual ACM Conference on Human Factors in Computing Systems, 2015.

R. H. Chowdhury, M. B. Reaz, Ali, Mohd Alauddin Bin Mohd, A. A. Bakar, K. Chellappan and T. G. Chang, "Surface electromyography signal processing and classification techniques," Sensors, vol. 13, (9), pp. 12431-12466, 2013.

M. A. Hemingway, H. Biedermann and J. Inglis, "Electromyographic recordings of paraspinal muscles: variations related to subcutaneous tissue thickness," Biofeedback Self., vol. 20, (1), pp. 39-49, 1995.

M. R. Al-Mulla, F. Sepulveda and M. Colley, "A review of non-invasive techniques to detect and predict localised muscle fatigue," Sensors, vol. 11, (4), pp. 3545-3594, 2011.

K. WoŸniak, D. Piątkowska, M. Lipski and K. Mehr, "Surface electromyography in orthodontics–a literature review," Medical Science Monitor: International Medical Journal of Experimental and Clinical Research, vol. 19, pp. 416, 2013.

I. Campanini, A. Merlo, P. Degola, R. Merletti, G. Vezzosi and D. Farina, "Effect of electrode location on EMG signal envelope in leg muscles during gait," Journal of Electromyography and Kinesiology, vol. 17, (4), pp. 515-526, 2007.

C. Hansen, F. Gosselin, K. B. Mansour, P. Devos and F. Marin, "Design-validation of a hand exoskeleton using musculoskeletal modeling," Appl. Ergon., vol. 68, pp. 283-288, 2018.

Hardware Integration with NI LabVIEW. Available online 5th March 2019 (Accessed 9th May 2020).

J. Guerreiro, R. Martins, H. Silva, A. Lourenço and A. L. Fred, "BITalino-A multimodal platform for physiological computing," in Icinco (1), 2013.

H. P. Da Silva, J. Guerreiro, A. Lourenço, A. L. Fred and R. Martins, "BITalino: A novel hardware framework for physiological computing." in PhyCS, 2014.

Electromyography (EMG) Sensor Data Sheet. Available (Accessed 9th May 2020).

A. Savitzky and M. J. E. Golay, "Smoothing and differentiation of data by simplified least squares procedures," Anal. Chem., vol. 36, (8), pp. 1627-1639, 1964.

V. Gandhi and T. M. McGinnity, "Quantum neural network based surface EMG signal filtering for control of robotic hand," in IEEE International Joint Conference on Neural Networks, 2013.

W. Lu, C. Huang, K. Hou, L. Shi, H. Zhao, Z. Li and J. Qiu, "Recurrent neural network approach to quantum signal: coherent state restoration for continuous-variable quantum key distribution," Quantum Information Processing, vol. 17, (5), pp. 109, 2018.

N. Miljković, N. Popović, O. Djordjević, L. Konstantinović and T. B. Šekara," ECG artifact cancellation in surface EMG signals by fractional order calculus application," Comput. Methods Programs Biomed., vol. 140, pp. 259-264, 2017.

A. Phinyomark, E. Campbell and E. Scheme, "Surface electromyography (EMG) signal processing, classification, and practical considerations," in Biomedical Signal Processing, 2020.

C. Gilliam, A. Bingham, T. Blu and B. Jelfs, "Time-varying delay estimation using common local all-pass filters with application to surface electromyography," in 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2018.

A. Syed, Z. T. H. Agasbal, T. Melligeri and B. Gudur, "Flex sensor based robotic arm controller using micro controller," 2012.

D. Copaci, E. Cano, L. Moreno and D. Blanco, "New design of a soft robotics wearable elbow exoskeleton based on shape memory alloy wire actuators," Applied Bionics and Biomechanics, vol. 2017, 2017.

D. Copaci, D. Blanco, A. Martin-Clemente and L. Moreno, "Flexible shape memory alloy actuators for soft robotics: Modelling and control," International Journal of Advanced Robotic Systems, vol. 17, (1), pp. 1729881419886747, 2020.

P. Salvini, "On ethical, legal and social issues of care robots," in Intelligent Assistive Robots, 2015.

Z. Dolic, R. Castro and A. Moarcas, "Robots in Healthcare: A Solution or a Problem?," Policy Department for Economic, Scientific and Quality of Life Policies, Directorate General for Internal Policies, European Parliament, 2019.

P. Maurice, L. Allienne, A. Malaisé and S. Ivaldi, "Ethical and social considerations for the introduction of human-centered technologies at work," in 2018 IEEE Workshop on Advanced Robotics and its Social Impacts (ARSO), 2018.

E. Fosch-Villaronga, C. Lutz and A. Tamò-Larrieux, "Gathering expert opinions for social robots’ ethical, legal, and societal concerns: Findings from four international workshops," International Journal of Social Robotics, pp. 1-18, 2019.

H. Felzmann, A. Kapeller, A. Hughes and E. Fosch-Villaronga, "Ethical, legal and social issues in wearable robotics: Perspectives from the work of the COST action on wearable robots," in International Conference on Inclusive Robotics for a Better Society, 2018.

D. Greenbaum, "Ethical, legal and social concerns relating to exoskeletons," ACM SIGCAS Computers and Society, vol. 45, (3), pp. 234-239, 2016.

R. Calo, "Robotics and the Lessons of Cyberlaw," Calif. Law Rev., pp. 513-563, 2015.

J. Yang, K. Abdel-Malek and K. Nebel, "The Reach Envelope of a 9 Degree-of-Freedom Model of the Upper Extremity," International Journal of Robotics and Automation, vol. 20, pp. 240–259, 2005.

K. Bharadwaj and T. G. Sugar, "Kinematics of a robotic gait trainer for stroke rehabilitation," in Proceedings 2006 IEEE International Conference on Robotics and Automation (ICRA 2006), 2006.

Article Metrics

Metrics Loading ...

Metrics powered by PLOS ALM


  • There are currently no refbacks.

Copyright (c) 2020 Journal of Mechatronics, Electrical Power, and Vehicular Technology

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.