Design and Implementation of a Three-Segment Tendon-Driven Continuum Robot with Variable Stiffness for Manipulation...

Area of Science:

• Robotics
• Mechanical Engineering
• Materials Science

Background:

• Continuum robots (CRs) offer high compliance and adaptability in confined spaces.
• Their low stiffness and load capacity limit precise positioning and stable support capabilities.
• Addressing the "soft-rigid" paradox is crucial for expanding CR applications.

Purpose of the Study:

• To propose and implement a three-segment tendon-driven variable-stiffness continuum robot.
• To enhance bending consistency, motion predictability, and stiffness control.
• To reduce driver complexity and kinematic challenges in multi-segment CRs.

Main Methods:

• Utilized a segmented constant-curvature model for structural optimization.
• Employed elongated flat airbag actuators for segment-level stiffness switching.
• Implemented a time-sharing drive strategy to decouple multi-segment control.

Main Results:

• Flexible-mode joints maintained near-constant curvature with <0.9 mm trajectory error.
• Rigid mode demonstrated a 5.77x stiffness increase (4.0 N load capacity).
• Shape-locking disturbances were <1.32 mm, with successful pipeline path traversals.

Conclusions:

• The developed CR system offers a practical and scalable solution for variable stiffness and low-complexity multi-segment control.
• This research provides valuable insights for applications in minimally invasive surgery and industrial endoscopy.
• The variable-stiffness CR effectively balances compliance with the need for precise and stable operations in challenging environments.