A Novel Miniature Interventional Robot With Shape-Sensing and Closed-Loop Control for ERCP

This article proposes an interventional robot with shape-sensing and closed-loop control that integrates multiple functionalities to address the technical challenges in endoscopic retrograde cholangiopancreatography, such as intricate curvatures and trans-luminal navigation. The robot has a diameter of 3.8 mm, an active bending angle of 110°, and 3 degree-of-freedom. It can be introduced through the working channel of a duodenoscope to reach the biliary and pancreatic ducts. By incorporating real-time shape reconstruction based on fiber Bragg grating sensing, the platform enables closed-loop control of the tip, enhancing positional accuracy during biliary/pancreatic interventions. The shape reconstruction accuracy reaches 0.247 mm. Experiments demonstrate that closed-loop control enhances system performance by 84.5% in accuracy and 65.5% in stability compared to open-loop control. Trajectory tracking tests achieved root mean square errors of 0.290 mm (circular trajectory), 0.267 mm (helical trajectory), and 1.133 mm (grating trajectory), with instantaneous incremental angular errors of 0.031°, 0.030°, and 0.207°, respectively. Phantom-based functional validation successfully replicates clinical workflows, including intervention, water-jet, stone extraction, and biopsy under direct visualization. Results demonstrated the system’s ability to improve procedural accuracy with direct visualization, while maintaining flexibility in narrow luminal environments, showing potential to reduce procedure time and complication risks.