A Soft Magnetic Jamming Method Enabling Variable Stiffness and Active Steering for Robotic Catheter

Area of Science:

• Biomedical Engineering
• Materials Science
• Robotics

Background:

• Endovascular interventions require catheters with both steering and variable stiffness (VS) capabilities.
• Current methods often use multiple systems, leading to bulkiness, reduced efficiency, and safety concerns.

Purpose of the Study:

• To introduce a novel, single-source magnetic jamming method for achieving both steering and VS in endovascular catheters.
• To develop and validate a physics-based model correlating magnetic field parameters with catheter performance.

Main Methods:

• Developed a carrier-free, matrix-free magnetic jamming scheme encapsulating soft-magnetic powder in coaxial tubes.
• Established an analytical micro-to-macro stiffness model linking field parameters and particle properties to stiffness and steering.
• Validated the magnetic jamming method and stiffness model on catheter prototypes.

Main Results:

• Demonstrated single-source, field-driven steering and reversible VS through interparticle jamming.
• Achieved substantial field-tunable stiffness modulation (up to 300-fold).
• Validated the physics-based stiffness model and prototype performance against vacuum jamming.

Conclusions:

• The magnetic jamming approach enables on-demand steering and rapid, large-range stiffness modulation in millimeter-scale catheters.
• This technology offers potential for faster navigation, stable device deployment, and workflow-friendly autonomous endovascular interventions.