Abstract
There exist several hand exoskeletons systems that provide assistive force to the user for strength enhancement or rehabilitation. However, the lack of stability analyses for such systems has made it difficult to ensure that these systems can apply assistance forces corresponding to the user’s intended motion. In this study, a tendon-driven soft hand exoskeleton was developed to provide assistive grip force, and the qualitative stability condition of the system was investigated during system operation. The proposed exoskeleton assisted the middle finger, index finger, and thumb, based on the fingertip force estimated using a previously developed fingertip force sensor. This system applies a flexion force for the middle and index fingers, as well as flexion and abduction forces for the thumb. Because the stability of the system is important during the operation of the system, we qualitatively analyzed the stability condition of the system based on the modified form of the generalized unstructured model comprising the user’s finger, exoskeleton, and external environment. An experimental verification of the stability criterion was performed to determine the approximate range of the stably applicable assistance gain. This study is the first to quantify the stability of fingertip sensor-based assistive power being applied to the hand.
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References
Feix, T., Romero, J., Schmiedmayer, H.-B., Dollar, A. M., & Kragic, D. (2016). The GRASP taxonomy of human grasp types. IEEE Transactions on Human-Machine Systems, 46(1), 66–77.
Heo, P., Gu, G. M., Lee, S., Rhee, K., & Kim, J. (2012). Current hand exoskeleton technologies for rehabilitation and assistive engineering. International Journal of Precision Engineering and Manufacturing, 13(5), 807–824.
Zhou, Y. M. et al. (2019). Soft robotic glove with integrated sensing for intuitive grasping assistance post spinal cord injury. In 2019 International conference on robotics and automation (ICRA), pp. 9059–9065.
Yun, S.-S., Kang, B. B., & Cho, K.-J. (2017). Exo-glove PM: an easily customizable modularized pneumatic assistive glove. IEEE Robotics and Automation Letters, 2(3), 1725–1732.
Agarwal, P., Yun, Y., Fox, J., Madden, K., & Deshpande, A. D. (2017). Design, control, and testing of a thumb exoskeleton with series elastic actuation. The International Journal of Robotics Research, 36(3), 355–375.
Heo, P., & Kim, J. (2014). Power-assistive finger exoskeleton with a palmar opening at the fingerpad. IEEE Transactions on Biomedical Engineering, 61(11), 2688–2697.
Lee, B., Lee, S. C., & Han, C. (2020). Design of fixations for an exoskeleton device with joint axis misalignments. International Journal of Precision Engineering and Manufacturing, 21(7), 1291–1298.
Kim, J., Kim, J. W., Kim, H. C., Zhai, L., Ko, H. U., & Muthoka, R. M. (2019). Review of soft actuator materials. International Journal of Precision Engineering and Manufacturing, 20(12), 2221–2241.
Popov, D., Gaponov, I., & Ryu, J. H. (2017). Portable exoskeleton glove with soft structure for hand assistance in activities of daily living. IEEE/ASME Transactions on Mechatronics, 22(2), 865–875.
Kang, B. B., Choi, H., Lee, H., & Cho, K. J. (2019). Exo-glove poly II: a polymer-based soft wearable robot for the hand with a tendon-driven actuation system. Soft Robotics, 6(2), 214–227.
Cho, H., Lee, H., Kim, Y., & Kim, J. (2017). Design of an optical soft sensor for measuring fingertip force and contact recognition. International Journal of Control, Automation and Systems, 15(1), 16–24.
Kim, D., et al. (2019). Eyes are faster than hands: A soft wearable robot learns user intention from the egocentric view. Science Robotics, 4(26), eaav2949.
Lenzi, T., De Rossi, S. M. M., Vitiello, N., & Carrozza, M. C. (2012). Intention-based EMG control for powered exoskeletons. IEEE Transactions on Biomedical Engineering, 59(8), 2180–2190.
Yun, Y. et al. (2017). Maestro: An EMG-driven assistive hand exoskeleton for spinal cord injury patients. In 2017 IEEE international conference on robotics and automation (ICRA), pp. 2904–2910.
Lee, J., Kim, M., & Kim, K. (2017). A control scheme to minimize muscle energy for power assistant robotic systems under unknown external perturbation. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 25(12), 2313–2327.
Kyeong, S., Na, Y., & Kim, J. (2020). A mechatronic mirror-image motion device for symmetric upper-limb rehabilitation. International Journal of Precision Engineering and Manufacturing, 21, 947–956. https://doi.org/10.1007/s12541-019-00310-x.
Mathiowetz, V., Kashman, N., Volland, G., Weber, K., Dowe, M., & Rogers, S. (1985). Grip and pinch strength: Normative data for adults. Archives of Physical Medicine and Rehabilitation, 66(2), 69–74.
Park, J., Heo, P., Kim, J., & Na, Y. (2020). A finger grip force sensor with an open-pad structure for glove-type assistive devices. Sensors, 20(1), 4. https://doi.org/10.3390/s20010004.
Björkstén, M., & Jonsson, B. (1977). Endurance limit of force in long-term intermittent static contractions. Scandinavian Journal of Work, Environment & Health, 3(1), 23–27.
Acknowledgements
This research was supported by Sookmyung Women’s University Research Grants (1-1903-2014). This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government(MSIT) (No. 2020R1C1C1008424).
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Park, J., Heo, P., Kim, J. et al. Qualitative Stability Analysis of Soft Hand Exoskeleton Based on Tendon-driven Mechanism. Int. J. Precis. Eng. Manuf. 21, 2095–2104 (2020). https://doi.org/10.1007/s12541-020-00383-z
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DOI: https://doi.org/10.1007/s12541-020-00383-z