An Integrated Sensor-Model Approach for Haptic Feedback of Flexible Endoscopic Robots

Area of Science:

• Robotics
• Biomedical Engineering
• Sensor Technology

Background:

• Haptic feedback in flexible endoscopic surgical robots is difficult due to sensor space constraints and tendon-sheath mechanism (TSM) force hysteresis.
• Existing methods struggle with the complex mechanics and limited space within endoscopic robotic arms.

Purpose of the Study:

• To develop a compact, accurate force sensor for TSMs in endoscopic robotic arms.
• To create an integrated sensor-model approach for estimating forces across multiple TSMs using a single sensor.
• To enable effective haptic feedback in space-constrained robotic surgery.

Main Methods:

• A single-axis fiber Bragg grating (FBG) based force sensor was designed and integrated onto the distal sheath of a TSM.
• The sensor's temperature compensation and robust structure were utilized for accurate force measurement.
• A sensor-model approach was employed, using data from the single sensor to identify parameters for force-transmission models of other TSMs.
• An animal study was conducted to validate the system's performance in a surgical context.

Main Results:

• The FBG-based force sensor achieved a measurement error of 0.37 N.
• The integrated sensor-model approach estimated distal forces with a Root Mean Square Error (RMSE) of 0.65 N.
• The system demonstrated feasibility in a real-life animal surgical study.

Conclusions:

• The proposed sensor-model approach provides a robust, space-saving, and cost-effective solution for haptic feedback in endoscopic robots.
• This method overcomes limitations of space constraints and complex TSM hysteresis without assumptions on robot shape.
• The technology holds significant potential for enhancing surgical precision and safety in minimally invasive procedures.