Patent Application for Twisted String Actuator (TSA) for Robotics and Haptic Devices

Strategic Insights -

A Japanese inventor has filed a patent application for an actuator that converts rotational motion into linear motion using twisted wires, aiming to improve the performance of robots, braces, and haptic devices. This innovative design addresses the problem of over-twisting in existing actuators, which can lead to unstable stroke and torque. The new actuator configuration enables a larger amount of stroke without over-twisting and is designed to be used in a variety of applications.

Key Takeaways:

  • The patented actuator uses a twisted string configuration to convert rotational motion into linear motion, allowing for a larger amount of stroke without over-twisting.
  • Each wire is fixed to the support member in a state of being twisted in advance in the same twist rotation direction.
  • When the distance between the support member and the load is reduced, the wires are rotated in the same rotation direction as the twist direction and then twisted together.
  • The actuator can be used in robots, braces, and haptic devices to improve performance and assist in movement or provide a virtual sense of touch.
  • The wires can be made of ultra-high molecular weight polyethylene or be stranded wires with multiple element wires twisted together to increase strength.

Statistics:

  • The patent application was filed on October 16, 2024.
  • The patent application was posted on May 29, 2025.
  • The claims of the patent application number 20250172198 include 7 distinct inventions, including the actuator and its applications in robots, braces, and haptic devices.
  • The inventor, Kazutoshi Nishii, is affiliated with Toyota Jidosha Kabushiki Kaisha.

Sources:

  • NISHII, Kazutoshi. Actuator, And Robot, Brace, And Haptic Device Including The Same. U.S. Patent Application Number 20250172198, filed October 16, 2024 and posted May 29, 2025. Patent URL (for desktop use only): https://ppubs.uspto.gov/pubwebapp/external.html?q=(20250172198)&db=US-PGPUB&type=ids
  • VerticalNews, Jun 16, 2025, VerticalNews: Business, Robotics, Machine Learning, Emerging Technologies, Toyota Jidosha Kabushiki Kaisha