Many exoskeleton systems use a cable-pulley mechanism for actuation for complex hand grips. This paper discusses a trajectory control of a finger using a mathematical model. The soft glove is designed based on the conceptual framework of a natural skeletal finger. A two-link mechanism forms the kinematic model of the finger joints and soft actuators. The design has a natural claw-like position for distal and middle phalanges during flexion. The cable passes through specially designed pulleys and anchors. An experiment is conducted to validate the controller model in predicting the finger position. A flex sensor measures the actual joint angle during flexion. The results indicate that the model is accurate in attaining the desired angular displacement. The controller is more accurate for lower joint angles of the finger. The model demonstrates potential in Continuous Passive Movement (CPM), task training exercises, and rehabilitation applications.

1. Yap, H. K., Lim, J. H., Nasrallah, F., Goh, J. C. H., & Yeow, C. H. (2016). Characterization and evaluation of soft elastomeric actuators for hand assistive and rehabilitation applications. Journal of Medical Engineering & Technology, 40(4), 199–209. https://doi.org/10.3109/03091902.2016.1161853
2. Chiri, A., Vitiello, N., Giovacchini, F., Roccella, S., Vecchi, F., & Carrozza, M. C. (2012). Mechatronic design and characterization of the index finger module of a hand exoskeleton for post-stroke rehabilitation. IEEE Transactions on Mechatronics, 17(5), 884–894. https://doi.org/10.1109/TMECH.2011.2144614
3. Ali, S., et al. (2019). An adaptive multi-robot therapy for improving joint attention and imitation of ASD children. IEEE Access, 7, 81808–81825. https://doi.org/10.1109/ACCESS.2019.2923678
4. Fontana, M., Dettori, A., Salsedo, F., & Bergamasco, M. (2009). Mechanical design of a novel hand exoskeleton for accurate force displaying. In Proceedings of the 2009 IEEE International Conference on Robotics and Automation (pp. 1704–1709). https://doi.org/10.1109/ROBOT.2009.5152591
5. Wege, A., & Hommel, G. (2005). Development and control of a hand exoskeleton for rehabilitation of hand injuries. In Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (pp. 3046–3051). https://doi.org/10.1109/IROS.2005.1545506
6. In, H., Kang, B. B., Sin, M., & Cho, K. (2015). Exo-Glove: A wearable robot for the hand with a soft tendon routing system. IEEE Robotics & Automation Magazine, 22(1), 97–105. https://doi.org/10.1109/MRA.2014.2362863
7. Kang, B. B., Lee, H., In, H., Jeong, U., Chung, J., & Cho, K. J. (2016). Development of a polymer-based tendon-driven wearable robotic hand. In Proceedings of the 2016 IEEE International Conference on Robotics and Automation (pp. 3750–3755). https://doi.org/10.1109/ICRA.2016.7487562
8. Shahid, T., Gouwanda, D., Nurzaman, S., & Gopalai, A. (2018). Moving toward soft robotics: A decade review of the design of hand exoskeletons. Biomimetics, 3(3), 17. https://doi.org/10.3390/biomimetics3030017
9. Xiloyannis, M., Cappello, L., Khanh, D. B., Yen, S.-C., & Masia, L. (2016). Modelling and design of a synergy-based actuator for a tendon-driven soft robotic glove. In Proceedings of the 2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics (pp. 1213–1219). https://doi.org/10.1109/BIOROB.2016.7523796
10. Radder, B., Prange-Lasonder, G. B., Kottink, A. I., Gaasbeek, L., Sletta, K., Holmberg, J., Meyer, T., Buurke, J. H., & Rietman, J. S. (2017). Preliminary evaluation of a wearable soft-robotic glove supporting grip strength in ADL. In Converging Clinical and Engineering Research on Neurorehabilitation II (pp. 1245–1250). Springer. https://doi.org/10.1177/2055668316670553
11. Khatik, V., Nishad, S. S., & Saxena, A. (2020). Comprehending finger flexor tendon pulley system using a computational analysis. arXiv. https://arxiv.org/abs/2010.02580
12. Leeflang, S., & Coert, J. (2014). The role of proximal pulleys in preventing tendon bowstringing: Pulley rupture and tendon bowstringing. Journal of Plastic, Reconstructive & Aesthetic Surgery, 67(6), 822–827. https://doi.org/10.1016/j.bjps.2014.01.041
13. Lee, K. S., & Jung, M. C. (2015). Ergonomic evaluation of biomechanical hand function. Safety and Health at Work, 6(1), 9–17. https://doi.org/10.1016/j.shaw.2014.09.002
14. Alipour, A. H. K., Kazeminasab, S., & Elahinia, M. (2018). ASR glove: A wearable glove for hand assistance and rehabilitation using shape memory alloys. Journal of Intelligent Material Systems and Structures, 29(8), 1575–1585. https://doi.org/10.1177/1045389X17742729
15. Takagi, M., Iwata, K., Takahashi, Y., Yamamoto, S. I., Koyama, H., & Komeda, T. (2009). Development of a grip aid system using air cylinders. In Proceedings of the 2009 IEEE International Conference on Robotics and Automation (pp. 2312–2317). https://doi.org/10.1109/ROBOT.2009.5152246
16. Shahid, T., Gouwanda, D., Nurzaman, S. G., Gopalai, A. A., & Kheng, T. K. (2021). Development of an electrooculogram-activated wearable soft hand exoskeleton. In Proceedings of the 2021 IEEE-EMBS Conference on Biomedical Engineering and Sciences (pp. 433–438). https://doi.org/10.1109/IECBES48179.2021.9398797