Design of Portable Semi-Active Upper-Limb Exoskeleton for Long-Term Working Assistance

Strategic Insights -

Researchers from Tianjin University have designed a portable semi-active upper-limb exoskeleton to address the challenges of long-term working in fixed postures. The exoskeleton is equipped with three pneumatic-driven variable-stiffness units, including a bending actuator, a tensile actuator, and a teeth-engagement clutch. This innovative design aims to reduce muscle fatigue and musculoskeletal disorders associated with long-term working in fixed postures.

Key Takeaways:

  • The exoskeleton is controlled by a portable pneumatic system and weighs 3.35 kg, making it a lightweight and portable solution for workers.
  • The bending variable-stiffness actuator achieved 50.98-Nm/rad bending stiffness and 87.9-fold stiffness variation ratio at a relatively low vacuum pressure of 40 kPa.
  • The exoskeleton was tested on twelve healthy subjects, who showed a 42.3 +/- 2.4% reduction in muscular activation level while maintaining four commonly-used postures in assembly work.
  • The proposed exoskeleton design has the potential to provide long-term working assistance in fixed overhead and ahead postures, reducing the risk of musculoskeletal disorders.
  • The study's findings have been peer-reviewed and published in IEEE Robotics and Automation Letters, a reputable journal in the field of robotics and automation.
  • The research was funded by the Tianjin Municipal Science and Technology Program, demonstrating the importance of government support for innovative research in robotics and automation.
  • The team of researchers, led by Baojun Chen, includes Zhichao Hua, Qiang Lin, and Tianfang Li, all from Tianjin University.

Statistics:

  • 50.98-Nm/rad bending stiffness achieved by the bending variable-stiffness actuator
  • 87.9-fold stiffness variation ratio achieved at a relatively low vacuum pressure of 40 kPa
  • 3.35 kg: the total mass of the exoskeleton
  • 42.3 +/- 2.4%: the reduction in muscular activation level among twelve healthy subjects
  • 40 kPa: the relatively low vacuum pressure used in testing the exoskeleton
  • 4: the number of commonly-used postures in assembly work maintained by the subjects
  • 12: the number of healthy subjects tested in the study

Sources:

  • A Portable Upper-limb Exoskeleton With Pneumatic-driven Variable-stiffness Units for Long-term Working In Fixed Overhead and Ahead Postures. Ieee Robotics and Automation Letters, 2025;10(6):6240-6247.
  • Ieee Robotics and Automation Letters can be contacted at: Ieee-inst Electrical Electronics Engineers Inc, 445 Hoes Lane, Piscataway, NJ 08855-4141, USA.
  • NewsRx. Findings on Robotics and Automation Detailed by Investigators at Tianjin University (A Portable Upper-limb Exoskeleton With Pneumatic-driven Variable-stiffness Units for Long-term Working In Fixed Overhead and Ahead Postures). Robotics & Machine Learning. June 30, 2025; p 128.