Shape Tracking of a Dexterous Continuum Manipulator Utilizing Two Large Deflection Shape Sensors

Area of Science:

• Medical Robotics
• Sensing Technologies
• Minimally Invasive Surgery

Background:

• Dexterous continuum manipulators (DCMs) offer enhanced reach and steerability in minimally invasive surgery.
• Accurate real-time shape sensing is critical for controlling DCMs, especially during large deflections.
• Existing sensors may not adequately capture the complex shapes required for procedures like osteolysis treatment.

Purpose of the Study:

• To develop and validate a novel shape sensor capable of accurately tracking large deflections in a 35 mm DCM.
• To assess the sensor's performance in various bending scenarios, including those with obstacles.
• To enable precise control and improve outcomes in less invasive surgical interventions.

Main Methods:

• Embedding two shape sensors, each with three fiber Bragg grating (FBG) sensing nodes, within the DCM.
• Computing the DCM centerline based on the reconstructed sensor curves.
• Utilizing an experimental platform with a linear slide stage for controlled actuation and a 2D camera for verification.
• Comparing sensor-based shape reconstruction with ground truth derived from 2D-3D registration.

Main Results:

• The FBG shape sensor demonstrated high accuracy in tracking the DCM's distal tip.
• Distal tip tracking accuracy was 0.40 ± 0.30 mm in free bending.
• Accuracy in bending with obstacles ranged from 0.23 ± 0.10 mm to 0.93 ± 0.05 mm.

Conclusions:

• FBG arrays provide an accurate method for characterizing the shape of large-deflection DCMs.
• The developed sensor system is suitable for real-time shape monitoring in demanding surgical environments.
• This technology has the potential to enhance the safety and efficacy of robot-assisted minimally invasive procedures.