Wire-driven flexible manipulator with constrained spherical joints for minimally invasive surgery

Area of Science:

• Robotics
• Mechanical Engineering
• Surgical Technology

Background:

• Flexible robots are crucial for minimally invasive surgery but suffer from reduced rigidity and accuracy due to twist deformation and non-constant curvature.
• Conventional kinematic models often assume constant curvature, which does not reflect the real-world behavior of these robots.

Purpose of the Study:

• To propose a novel flexible manipulator design that improves rigidity and accuracy for minimally invasive surgery.
• To prevent twist deformation and ensure constant curvature in flexible robots.

Main Methods:

• A new flexible manipulator incorporating ball-constrained spherical (BCS) joints and springs was developed.
• BCS joints limit axial rotation to prevent twist deformation, while strategically placed springs ensure constant curvature.
• The BCS joint design is optimized based on forceps diameter, workspace, and desired bending angles.

Main Results:

• A prototype with 13 BCS joints demonstrated the ability to achieve constant curvature with a mean error of 0.21°.
• The mechanism effectively supported up to 5 N of force without significant twist deformation.
• Experimental validation confirmed the prototype's performance in maintaining constant curvature and resisting twist.

Conclusions:

• A novel flexible manipulator with BCS joints was successfully developed for minimally invasive surgery applications.
• The proposed design is expected to enhance robot rigidity and accuracy by preventing twist deformation and maintaining constant curvature.
• This advancement holds significant potential for improving surgical outcomes in procedures requiring flexible robotic instruments.