Design of an Optimal 4-bar Mechanism Based Gravity Balanced Leg Orthosis

  • Ved Prakash Choudhary
  • Vipin Kumar Singh
  • Ashish Dutta


In this paper we propose the design and control of a 4-bar mechanism based gravity balanced orthosis for providing gait training to persons with disability. Human leg joints have a varying instantaneous centre of rotation and hence 4-bar mechanisms have been used to actuate the orthosis joints. Human gait is first recorded using a vision system and the hip and knee joint trajectories extracted from the data. Optimal 4-bar mechanisms are then designed using a genetic algorithm that gives the smallest mechanism that can replicate the hip and knee joint trajectories accurately. The orthosis joints are gravity balanced so that the potential energy of the system in any orientations is constant, and the wearer does not feel the weight of the system. Experimental and simulation results prove that the exoskeleton can effectively model the changing centre of rotation of the hip and knee joints and follow the desired human trajectories.


4-bar mechanism Leg orthosis Gravity balancing Human gait 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Dollar, A.M., Herr, H.: Lower extremity exoskeletons and active orthoses: challenges and state-of-the-art. IEEE Trans. Robot. 24(1), 144–158 (2008)CrossRefGoogle Scholar
  2. 2.
    Vukobratavic, M., Hristic, D., Stojiljkovic, Z.: Development of active anthropomorphic exoskeletons. J. Med. Biol. Eng. 12(1), 66–80 (1974)CrossRefGoogle Scholar
  3. 3.
    Kazerooni, H., Steger, R.: The berkeley lower extremity exoskeleton. Trans. ASME 128, 14–25 (2006)CrossRefGoogle Scholar
  4. 4.
    Chu, A., Kazerooni, H., Zoss, A.: On the biomimetic design of the berkeley lower extremity exoskeleton (BLEEX). IEEE International Conference on Robotics and Automation, 4345–4352 (2005)Google Scholar
  5. 5.
    Chu, A., Kazerooni, H., Zoss, A.: Biomechanical design of the berkeley lower extremity exoskeleton (BLEEX). IEEE/ASME Trans. Mechatron. 11(2), 128–138 (2006)CrossRefGoogle Scholar
  6. 6.
    Suzuki, K., Mito, G., Kawamoto, H., Hasegawa, Y., Sankai, Y.: Intention-based walking support for paraplegia patients with robot suit HAL. Adv. Robot. 21(12) (2007)Google Scholar
  7. 7.
    Kawamoto, H., Kamibayashi, K., Nakata, Y., Yamawaki, K., Ariyasu, R., Sankai, Y., Sakane, M., Eguchi, K., Ochia, N.: Pilot study of locomotion improvement using hybrid assistive limb in chronic stroke patients. BMC Neurol. 13, p141 (2013)CrossRefGoogle Scholar
  8. 8.
    Farris, R.J., Quintero, H.A., Goldfarb, M.: Preliminary evaluation of a powered lower limb orthosis to aid walking in paraplegic individuals. IEEE Trans. Neural Syst. Rehabil. Eng. 19(6), 652–659 (2011)CrossRefGoogle Scholar
  9. 9.
    Agarwal, S.K., Fattah, A.: On the design of a passive orthosis to gravity balance human legs. Trans. ASME J. Mech. Des. 127(4), 802–808 (2005)CrossRefGoogle Scholar
  10. 10.
    Agarwal, S.K., Fattah, A.: Theory and design of an orthotic device for full or partial gravity-balancing of a human leg during motion. IEEE Int. Conf. Neural syst. Rehabil. Eng. 12(2), 157–165 (2004)CrossRefGoogle Scholar
  11. 11.
    Banala, S.K., Kim, S.H., Agarwal, S.K., Scholz, J.P.: Robot assisted gait training with active leg exoskeleton (ALEX). IEEE Trans. Neural Syst. Rehabil. Eng. 17(1), 2–8 (2009)CrossRefGoogle Scholar
  12. 12.
    Cestari, M., Merodio, D.S., Areval, J.C., Garcia, E.: An adjustable compliant joint for lower limb exoskeleton. IEEE Trans. Mechatron. 20(2), 889–898 (2015)CrossRefGoogle Scholar
  13. 13.
    Cullell, A., Moreno, J.C., Rocon, E., Forner, A., Pons, J.L.: Biologically based design of an actuator system for a knee ankle foot orthosis. Mech. Mach. Theory 44, 860–872 (2009)MATHCrossRefGoogle Scholar
  14. 14.
    Hussain, S., Xie, S.Q., Jamwal, P.K., Parsons, J.: An intrinsically compliant robotic orthosis for treadmill training. Med. Eng. Physis 34, 1448–1453 (2012)CrossRefGoogle Scholar
  15. 15.
    Hussain, S., Xie, S.Q., Jamwal, P.K.: Control of a robotic orthosis for gait rehabilitation. Robot. Auton. Syst. 61, 911–919 (2013)CrossRefGoogle Scholar
  16. 16.
    Yeh, T.J., Wu, M.J., Lu, T.J., Wu, F.K., Huang, C.R.: Control of McKibben pneumatic muscles for a power assist, lower limb orthosis. Mechatronics 20, 686–697 (2010)CrossRefGoogle Scholar
  17. 17.
    Chen, J., Liao, W.H.: Design and control of a magnetorheological actuator for leg exoskeleton. IEEE International Conference on Robotics and Biomimetics, 1388–1393 (2007)Google Scholar
  18. 18.
    Wu, S.K., Jordan, M., Shen, X.: A pneumatically-actuated lower-limb orthosis. IEEE International Conference on EMBS, 8126–8129 (2011)Google Scholar
  19. 19.
    Nagarajan, U., Aguirre-Ollinger, G., Goswami, A.: Integral admittance shaping : A unified framework for active exoskeleton control. Robot. Auton. Syst. 75, 310–324 (2016)CrossRefGoogle Scholar
  20. 20.
    Karavas, N., Ajoudani, A., Tsagarakis, N., Saglia, J., Bicchi, A., Caidwell, D.: Tele-impedance based assistive control for a compliant knee exoskeleton. Robot. Auton. Syst. 73, 78–90 (2015)CrossRefGoogle Scholar
  21. 21.
    Oh, S., Baek, E., Song, S.K., Mohammed, S., Jeon, D, Kong, K.: A generalized control framework of assistive controllers and its applications to lower limb exoskeletons. Robot. Auton. Syst. 73, 68–77 (2015)CrossRefGoogle Scholar
  22. 22.
    Galle, S., Malcolm, P., Derave, W, De Clercq, D.: Uphill walking with a simple exoskeleton: Planterflexion assistance leads to proximal adaptations. Gait Posture 41, 246–251 (2015)CrossRefGoogle Scholar
  23. 23.
    Aach, M., Cruciger, O., Kaiser, M.S., Schwenkreis, P., Sankai, Y, Schildhauer, T.A.: Voluntary driven exoskeleton as a new tool for rehabilitation in chronic spinal cord injury: a pilot study. Spine J. 14, 2847–2853 (2014)CrossRefGoogle Scholar
  24. 24.
    Chen, B., Ma, H., Qin, L.Y., Gao, F., Chan, K.M., Law, S.W., Qin, L., Liao, W.H.: Recent developments and challenges of lower extremity exoskeletons. J. Orthop. Trans. 5, 26–37 (2016)Google Scholar
  25. 25.
    Norton, R.L.: Design of machinery: An introduction to the synthesis and analysis of mechanisms and machines, 3rd edn. McGraw-Hill Higher Education (2004)Google Scholar
  26. 26.
    Cabrera, J.A., Simon, A., Prado, M.: Optimal synthesis of mechanisms with genetic algorithms. Mech. Mach. Theory 37, 1165–1177 (2002)MATHCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2017

Authors and Affiliations

  • Ved Prakash Choudhary
    • 1
  • Vipin Kumar Singh
    • 1
  • Ashish Dutta
    • 1
  1. 1.Department of Mechanical EngineeringIIT KanpurKanpurIndia

Personalised recommendations