An adaptive foot device for increased gait and postural stability in lower limb Orthoses and exoskeletons

Regular Papers Robotics and Automation


Assistive devices and exoskeletons have critical importance for people with manipulative and locomotive disabilities. One of the major purposes of such devices when used for lower extremities is to help provide the postural or gait stability of the user. However, current lower extremity exoskeletons available lack the sufficient foot support area to guarantee a safe operation for the rehabilitation of patients, and normal posture/gait for users carrying heavy loads on backpack. As a result, these devices may require an intensive control effort to supply the posture or gait stability and can demand additional therapist help during rehabilitation. In this paper, we proposed a novel adaptive foot system to enhance the required stability of lower extremity exoskeletons as an add-on device. The method essentially aims to automatically extend the support area behind the heel during walking. The proposed adaptive foot system can extend passively during stance and retract during the toe rocker phase, which allows increased support areas during stance and prevent collisions to the level ground during swing. It is practical to implement and can be employed without necessitating an actuation power. The proposed wearable system will particularly be valuable in rehabilitation for enhancing the stability where safety of patients is particularly critical. It is also anticipated that the system can be a complementary device for current exoskeletons or humanoid robots to enhance their stability. A detailed description and numerical analysis of the stability in sagittal plane is presented for postural and gait cases in this paper. Experiments have been also conducted to prove the effectiveness of the adaptive wearable device for postural and gait stability.


Adaptive foot device backpack lower extremity exoskeleton rehabilitation stability 


  1. [1]
    R. B. Dariush, “Analysis and simulation of an exoskeleton controller that accommodates static and reactive loads,” Proc. International Conference on Robotics and Automation, Spain, pp. 2350–2355, April 2005.Google Scholar
  2. [2]
    E. Guizzo and H. Goldstein, “The rise of the body bots,” IEEE Spectrum, vol. 42, no. 10, pp. 42–48, 2005.CrossRefGoogle Scholar
  3. [3]
    H. Kazerooni, R. Steger, and L. Huang, “Hybrid control of the berkeley lower extremity exoskeleton (BLEEX),” International Journal of Robotics Research, vol. 25, no. 5–6, pp. 561–573, May–June 2006.Google Scholar
  4. [4]
    J. Yoon, B. Novandy, C. Yoon, and K. Park, “A 6-DOF gait rehabilitation robot with upper and lowerlimb connections that allows walking velocity updates on various terrains,” IEEE/ASME Trans. on Mechatronics, vol. 15, no.2, pp. 201–215, 2010.CrossRefGoogle Scholar
  5. [5]
    A. M. Dollar, “Lower extremity exoskeletons and active orthoses: challenges and state-of-the-art,” IEEE Trans. on Robotics, vol. 24, no. 1, pp. 144–158, 2008.CrossRefGoogle Scholar
  6. [6]
    J. A. Blaya and H. Herr, “Adaptive control of a variable-impedance ankle-foot orthosis to assist drop-foot gait,” IEEE Trans. on Neural Systems and Rehabilitation Engineering, vol. 12, no. 1, 2004.Google Scholar
  7. [7]
    A. M. Dollar and H. Herr, “Lower extremity exoskeletons and active orthoses: challenges and state-of-the-art,” IEEE Trans. on Robotics, vol. 24, no. 1, 2008.Google Scholar
  8. [8]
    K. E. Gordon and D. P. Ferris, “Learning to walk with a robotic ankle exoskeleton,” Journal of Biomechanics, vol. 40, pp. 2636–2644, 2007.CrossRefGoogle Scholar
  9. [9]
    D. P. Ferris, G. S. Seasick, and A. R. Domingo, “Powered lower limb orthoses for gait rehabilitation,” Top Spinal Cord Inj. Rehabil, vol. 11, no. 2, pp. 34–49, 2005.CrossRefGoogle Scholar
  10. [10]
    S. Ito, Y. Saka, and H. Kawasaki, “Where center of pressure should be controlled in biped upright posture,” Systems and Computers in Japan, vol. 35, no. 5, pp. 23–31, 2004.CrossRefGoogle Scholar
  11. [11]
    L. Nashner and G. McCollum, “The organization of human postural movements: a formal basis and experimental synthesis,” The Behavioral and Brain Sciences, vol. 8, pp. 135–172, 1985.CrossRefGoogle Scholar
  12. [12]
    R. P. Kumar and J. Yoon, “Improved stability in lower extremity exoskeletons using foot extensions,” Proc. of ICROS-SICE International Joint Conference, August, Fukuoka, Japan, 2009.Google Scholar
  13. [13]
    M. Vukobratović and B. Borovac, “Zero-moment point-thirty five years of its life,” International Journal of Humanoid Robotics, vol. 1, no. 1, pp. 157–173, 2004.CrossRefGoogle Scholar
  14. [14]
    A. Goswami, “Postural stability of biped robots and the foot-rotation indicator (FRI) point,” International Journal of Robotics Research, vol. 18, no. 6, pp. 523–533, 1999.MathSciNetCrossRefGoogle Scholar
  15. [15]
    S. Park, Y. Han, and H. Hahn, “Balance control of a biped robot using camera image of reference object,” International Journal of Control, Automation, and Systems, vol. 7, no. 1, pp. 75–84, 2009.CrossRefGoogle Scholar
  16. [16]
    W. Yang and N. Y. Chong, “Imitation learning of humanoid locomotion using the direction of landing foot,” International Journal of Control, Automation, and Systems, vol. 7, no. 4, pp. 585 597, 2009.Google Scholar
  17. [17]
    J. Perry, Gait Analysis: Normal and Pathological Function, Slack Inc, Thorofare, NJ, 1992.Google Scholar
  18. [18]
    R. P. Kumar, J. Yoon, Christiand, and G. Kim, “The simplest passive dynamic walking model with toed feet: a parametric study,” Robotica, vol. 27, no. 5, pp. 701–713, 2009.CrossRefGoogle Scholar
  19. [19]
    Y. Laufer, “Effect of age on characteristics of forward and backward gait at preferred and accelerated walking speed,” Journal of Gerontology: Medical Sciences, vol. 60, no. 5, pp. 627–632, 2005.Google Scholar
  20. [20]
    D. Oeffinger, B. Brauchb, S. Cranfillb, C. Hisleb, C. Wynnb, R. Hicksb, and S. Augsburger, “Comparison of gait with and without shoes in children,” Gait & Posture, vol. 9, no. 2, pp. 95–100, 1999.CrossRefGoogle Scholar
  21. [21]
    S. Whitney, D. Wrisley, and J. Furman, “Concurrent validity of the berg balance scale and the dynamic gait index in people with vestibular dysfunction,” Physiotherapy Research International, vol. 8, no. 4, pp. 178–186, 2003.CrossRefGoogle Scholar

Copyright information

© Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Jungwon Yoon
    • 1
  • R. Prasanth Kumar
    • 2
  • Abdullah Özer
    • 1
  1. 1.School of Mechanical & Aerospace Engineering and ReCAPTGyeongsang National UniversityJinjuKorea
  2. 2.Research Center for Aircraft Parts TechnologyGyeongsang National UniversityJinjuKorea

Personalised recommendations