An Integrated Kinematic Modeling and Experimental Approach for an Active Endoscope

Area of Science:

• Robotics and Control Systems
• Medical Device Engineering
• Mechanical Engineering

Background:

• Continuum robots, with flexible backbones instead of joints, are ideal for miniaturized active endoscopes.
• Modeling and controlling these robots is challenging due to their inherent flexibility, especially for closed-loop medical applications.
• Existing modeling approaches (theoretical and experimental) have limitations in accuracy, computational cost, and capturing complex system interactions.

Purpose of the Study:

• To develop a hybrid approach merging theoretical and experimental methods for modeling endoscopic continuum robots.
• To create a simplified yet representative mathematical model based on Cosserat rod theory coupled with tendon tensions.
• To validate the model through a bespoke experimental facility with contactless sensing and precise tendon tension control.

Main Methods:

• Developed a simplified continuum robot model using Cosserat rod theory, integrated with tendon tension dynamics.
• Formulated a computationally efficient numerical technique for robot behavior prediction.
• Constructed an experimental setup for precise backbone motion control via tendon tensions and utilized contactless sensors for data acquisition.

Main Results:

• Achieved a mean real-world positioning error of 3.95% of backbone length, outperforming existing methods.
• Successfully incorporated hysteresis behavior, a phenomenon not predicted by theoretical modeling alone.
• Demonstrated a theoretically grounded and experimentally validated workflow for accurate continuum robot behavior prediction.

Conclusions:

• The hybrid theoretical-experimental approach provides accurate and robust modeling of continuum robots for endoscopic applications.
• This method overcomes limitations of purely theoretical or experimental approaches by integrating real-world observations.
• The geometrically agnostic model is scalable for various robotic endoscopes, enabling precise prediction and control.