Stiffness Optimisation and Kinematics Modelling of a Cable-Stayed Flexible Manipulator for Endoscopic Surgery

Area of Science:

• Robotics
• Mechanical Engineering
• Materials Science

Background:

• Cable-driven continuum robots exhibit a fundamental trade-off between stiffness and flexibility.
• Enhancing stiffness is a significant challenge in developing these robots for advanced applications.

Purpose of the Study:

• To present a novel stiffness-optimized cable-stayed notched manipulator (CSNM).
• To address the critical challenge of stiffness enhancement in cable-driven continuum robots.

Main Methods:

• Utilized Bernoulli-Euler beam theory for elastic beam (EB) deformation modeling and stiffness optimization.
• Employed a simplified piecewise constant-curvature assumption for kinematic modeling based on tendon lengths.
• Implemented an evolution-based EB optimization algorithm to achieve uniform stress distribution and enhance load capacity.

Main Results:

• The optimized manipulator exhibited a maximum elastic beam bending angle variance of 0.5°.
• Achieved maximum motion errors of 0.21 mm on the x-axis and 0.32 mm on the y-axis.
• Demonstrated a 100% increase in load capacity due to uniform stress distribution.

Conclusions:

• The structural optimization and kinematic modeling of the CSNM are validated by experimental results.
• The CSNM shows significant potential for endoscopic applications requiring both high flexibility and substantial load capacity.