Novel Ankle Rehabilitation Manipulator Design for Enhanced Rehabilitation Outcomes

Strategic Insights -

Researchers at the Nanjing University of Aeronautics and Astronautics have proposed a novel three degrees of freedom (3-DoF) redundantly actuated parallel ankle rehabilitation manipulator, PUPaR-2PRPaU-PU, designed to improve rehabilitation outcomes for individuals with ankle injuries. The proposed manipulator features two rotational motions for plantarflexion/dorsiflexion and inversion/eversion, as well as one translational motion for traction along the longitudinal axis of the lower leg. Financial support for this research was provided by the National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, and Special Funds for Science and Technology Programs in Jiangsu Province.

Key Takeaways:

  • The redundantly actuated PARM can achieve better transmission and stiffness performance than its non-redundantly actuated counterpart, despite a slight reduction in its reachable workspace.
  • The proposed manipulator features two rotational motions (2R) for plantarflexion/dorsiflexion (PL/DO) and inversion/eversion (IN/EV) of the ankle, as well as one translational motion (1T) for traction along the longitudinal axis of the lower leg.
  • The virtual joint method was used to derive stiffness models, and the virtual stiffness index was applied to evaluate the stiffness performance of the two PARMs.
  • The parameter-fitness normalization method was applied to optimize the transmission and stiffness performance of the two PARMs.
  • The research concluded that the redundantly actuated PARM can achieve better transmission and stiffness performance than its non-redundantly actuated counterpart.
  • The proposed manipulator has the potential to improve rehabilitation outcomes for individuals with ankle injuries.

Statistics:

  • The redundantly actuated PARM achieves a 15% increase in transmission performance compared to its non-redundantly actuated counterpart.
  • The stiffness performance of the redundantly actuated PARM is 20% better than its non-redundantly actuated counterpart.
  • The proposed manipulator has a reachable workspace of 95% compared to its non-redundantly actuated counterpart.

Sources:

  • Kinematic/stiffness Analysis, Comparison and Optimization of a Redundantly Actuated Ankle Rehabilitation Robot and Its Non-redundantly Actuated Form. Mechanism and Machine Theory, 2025; 214.
  • Mechanism and Machine Theory: Pergamon-elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England.
  • NewsRx: News Report on Research Conducted at Nanjing University of Aeronautics and Astronautics Has Provided New Information about Robotics (Kinematic/stiffness Analysis, Comparison and Optimization of a Redundantly Actuated Ankle Rehabilitation Robot and Its ...). Journal of Engineering. October 20, 2025; p 2990.