Development of an Inchworm‐Like Dual‐Balloon‐Assisted Colonoscopic Robot Based on a Two‐Segment Extensible Continuum Section

The clinical flexible colonoscopy, particularly when navigating through the sigmoid colon, is prone to forming loops due to the complex physiological structure characterized by sharp curves and nonfixed sites of the intestinal tract. This challenge commonly results in discomfort and pain for patients and increases the risk of complications. To address these issues, this work presents an inchworm‐like dual‐balloon‐assisted colonoscopic robot based on a rod‐driven two‐segment continuum section, in which the proximal segment uses a fixed‐length continuum joint with two bending DoFs. The distal segment employs an extensible continuum joint with 3 DoFs. Besides, an inchworm‐like locomotion strategy for the robot is proposed to achieve sigmoid colon straightening by alternating the extension/contraction of the two‐segment continuum section and the anchoring of the dual inflated balloons, thereby facilitating subsequent colonoscopy examinations. Characterization experiments are conducted to verify the performance of the proposed colonoscopic robot. It demonstrates an average 3D distal positioning error of less than 2.27 mm, indicating superior bending accuracy. The anchoring balloons achieve a maximum inflation diameter of over 70 mm at 5.75 kPa, demonstrating their ability to undergo large deformations at low air pressures. Moreover, three types of balloons with different surface patterns are evaluated to assess anchoring force. The experimental results show that the balloon with ribbon‐type patterns can generate an anchoring force of 3.87 N. Ex vivo experiments conducted on a porcine large intestine validate the feasibility of the proposed concept for flexible‐access colonoscopy.