Journal of Mechanical Science and Technology

, Volume 33, Issue 1, pp 357–366 | Cite as

Safety design and performance analysis of humanoid rehabilitation robot with compliant joint

  • Jian LiEmail author
  • Shuai Li
  • Yin Ke
  • Siqi Li


Human safety represents the key requirement in physical human-robot interaction (pHRI). However, the majority of current research works focus on the safety evaluation. There is no definite way to design a robot that not only meets the performance but also has inherent safety. A humanoid robot for human joint movement rehabilitation is developed, to fulfill the requirement of both safety and its performance. A nonlinear model of human-robot collision with effective mass and stiffness of robot’s end-effecter (EE) is proposed. An important parameter involved in the model is the joint stiffness of the robot, which has an inherent direct effect on the safety. The influence of joint compliance on the modal frequencies is analyzed, and the kinematic performance of the robot is estimated roughly by the lowest order modal frequency. The design method of compliant joint stiffness is put forward, which can balance the safety and kinematics performance requirements. When the compliance is utilized intentionally in joints to improve safety, the question whether or not rigid performance of compliant joint can be achieved or approached by control is arose naturally. Such a challenge is addressed by the cascade control, where outer position loop with link-side position feedback is constructed. Here, restoring torque in the elastic transmission is taken as virtual control that is, in turn, set as the reference command of the inner torque loop. Intuitively, once the virtual control is reproduced as rapidly as possible in the inner torque loop, quasi-rigid performance is exhibited in the outer position loop as if there were no series elasticity in compliant joint. The stability criterion is derived, and the virtual stiffness and dynamic performance are examined. Finally, experiments are performed to validate effectiveness of the suggested control scheme.


Humanoid rehabilitation robot Compliant joint Safety Modal frequency Cascade control 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [1]
    A. D. Santis, B. Siciliano, A. D. Luca and A. Bicchi, An atlas of physical human-robot interaction, Mechanism and Machine Theory, 43 (3) (2008) 253–270.CrossRefzbMATHGoogle Scholar
  2. [2]
    A. Albu-Schaffer, A. Bicchi and R. Chatila, Physical humanrobot interaction in anthropic domains: Safety and dependability, 4th IARP/IEEE-EURON Workshop on Technical Challenges for Dependable Robots in Human Environments, Nagoya (2005).Google Scholar
  3. [3]
    J. Carlsson, Robot accidents in Sweden, National Board of Occupational Safety and Health, Springer, Berlin (1985) 49–64.Google Scholar
  4. [4]
    R. Hirschfeld, F. Aghazadeh and R. Chapleski, Survey of robot safety in industry, International Journal of Human Factors in Manufacturing, 3 (4) (2007) 369–379.CrossRefGoogle Scholar
  5. [5]
    Y. Yamada, Y. Hirasawa, S. Huang and Y. Umetani, Human-robot contact in the safeguarding space, IEEE/ASME Transactions on Mechatronics, 2 (4) (1997) 230–236.CrossRefGoogle Scholar
  6. [6]
    M. Zinn, O. Khatib, B. Roth and J. Salisbury, Playing it safe: A new actuation concept for human-friendly robot design, IEEE Robotics and Automation Magazine, 11 (2) (2004) 12–21.Google Scholar
  7. [7]
    A. Bicchi and G. Tonietti, Fast and soft arm tactics, IEEE Robot. Autom. Magazine, 11 (2) (2004) 22–33.CrossRefGoogle Scholar
  8. [8]
    S. Haddadin, A. Albu-Schaffer, F. Haddadin and J. Rosmann, Study on soft-tissue injury in robotics, Robotics and Automation Magazine IEEE, 18 (4) (2011) 20–34.CrossRefGoogle Scholar
  9. [9]
    Y. Huang, Z. Li and X. Duan, Cascade control for compliant joint robots with redundant position sensors, IEEE 55th Conference on Decision and Control (CDC), Las Vegas, NV, USA (2016) 6427–6433.Google Scholar
  10. [10]
    P. V. Kokotovic, H. K. Khalil and J. O. Reilly, Singular perturbations methods in control: Analysis and design, Academic Press, New York (1986).Google Scholar
  11. [11]
    K. Kreutz-Delgado, M. Long and H. Seraji, Kinematic analysis of 7-DOF anthropomorphic arms, IEEE International Conference on Robotics and Automation, Cincinnati, OH, 2 (2) (1990) 824–830.CrossRefGoogle Scholar
  12. [12]
    Y. C. Huang et al., Design and implementation of dual-arm robot with homogeneous compliant joint, International Conference on Intelligent Human-Machine Systems and Cybernetics (IHMSC), Hangzhou, China (2017) 265–270.Google Scholar
  13. [13]
    K. Hunt and F. Crossley, Coefficient of restitution initerpreted as damping in vibro impact, ASME Journal of Applied Mechanics, 42 (1975) 440–445.CrossRefGoogle Scholar
  14. [14]
    J. J. Craig, Introduction to robotics: Mechanics and control, 3rd Ed., Pearson (2004).Google Scholar
  15. [15]
    D. C. Schneider and A. M. Nahum, Impact studies of facial bone and skull, Proceedings of the 16th Stapp Car Crash Conference, SAE Paper (1972) 186.Google Scholar
  16. [16]
    G. Gilardi and I. Sharf, Literature survey of contact dynamics modeling, Mechanism and Machine Theory, 37 (10) (2002) 1213–1239.MathSciNetCrossRefzbMATHGoogle Scholar
  17. [17]
    Y. Huang, P. Soueres and J. Li, Contact dynamics of massage compliant robotic arm and its coupled stability, IEEE International Conference on Robotics and Automation (ICRA), Hong Kong, China (2014) 1499–1504.Google Scholar
  18. [18]
    J. Li et al., Tradeoff between safety and performance for humanoid rehabilitation robot based on stiffness, IEEE International Conference on Mechatronics and Automation (ICMA), Takamatsu, Japan (2017) 1585–1590.Google Scholar
  19. [19]
    X. Y. Zeng et al., Fast solar sail rendezvous mission to near Earth asteroids, Acta Astronautica, 105 (2014) 40–56.CrossRefGoogle Scholar
  20. [20]
    X. Y. Zeng et al., Solar sail planar multireversal periodic orbits, Journal of Guidance, Control, and Dynamics, 37 (2) (2014) 674–681.Google Scholar

Copyright information

© The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Key Laboratory for Intelligent Control and Decision on Complex Systems, School of AutomationBeijing Institute of TechnologyBeijingChina
  2. 2.The Bionic Robot and System Key Laboratory, School of Mechatronical EngineeringBeijing Institute of TechnologyBeijingChina

Personalised recommendations