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Torsional Kinematic Model for Concentric Tube Robots
Pierre E Dupont1, Jesse Lock, Evan Butler
1Mechanical Engineering, Boston University, Boston, MA 02215 USA ( pierre@bu.edu ).
IEEE International Conference on Robotics and Automation : ICRA : [Proceedings]. IEEE International Conference on Robotics and Automation
|April 12, 2011
Summary
This study introduces a new mechanics model for steerable needles, incorporating torsion for precise control. The model predicts needle instability, validated by simulations and experiments.
Area of Science:
- Medical Devices
- Mechanical Engineering
- Robotics
Background:
- Steerable needles are crucial for minimally invasive surgery.
- Existing models often overlook torsional effects in pre-curved needle designs.
- Concentric tube designs offer controllable needle tip positioning and shape.
Purpose of the Study:
- To develop a comprehensive mechanics model for concentric tube steerable needles.
- To incorporate torsional effects and variable curvature/stiffness into the model.
- To enable analytic prediction of needle instability.
Main Methods:
- Developed a mechanics model for multi-tube concentric designs.
- Included torsion and variable properties along the needle's arc length.
- Derived an analytic solution for two tubes with constant curvature.
- Utilized simulations and experimental validation.
Main Results:
- The new model accurately captures needle behavior, including torsion.
- An analytic solution for constant curvature tubes predicts snap-through instability.
- A single dimensionless parameter governs this instability.
- Simulations and experiments confirm model predictions.
Conclusions:
- The presented mechanics model enhances the design and control of steerable needles.
- The inclusion of torsion provides a more accurate representation of needle mechanics.
- The analytic solution offers a valuable tool for predicting and avoiding instability during procedures.
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