Towards Semi-Autonomous Colon Screening Using an Electromagnetically Actuated Soft-Tethered Colonoscope Based on Visual Servo Control.

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Abstract

Conventional colonoscopy using a flexible colonoscope has two major limitations, including patient discomfort and difficult manipulations for surgeons. Robotic colonoscopes have been developed to provide new approaches to conducting colonoscopy in a patient-friendly manner. However, most robotic colonoscopes still face the challenge of nonintuitive and difficult manipulations, which limits their applications in clinical practice. In this paper, we demonstrated visual servo-based semi-autonomous manipulations of an electromagnetic actuated soft-tethered (EAST) colonoscope, which aims to improve the system’s autonomy level and lower difficulties of robotic colonoscope manipulations.Kinematic modeling of the EAST colonoscope is conducted, based on which an adaptive visual servo controller is established. Template matching technique and a deep-learning-based lumen and polyp detection model are developed, which are combined with visual servo control to enable semi-autonomous manipulations, including region-of-interest automatic tracking and autonomous navigation with automatic polyp detection.The EAST colonoscope demonstrates visual servoing with an average convergence time of around 2.5 s and a root-mean-square error of less than 5 pixels, and performs disturbance rejection within 3.0 s. Semi-autonomous manipulations were conducted in both a commercialized colonoscopy simulator and an ex-vivo porcine colon to show the efficacy of reducing the user workload compared to manual control.The EAST colonoscope can perform visual servoing and semi-autonomous manipulations with the developed methods in both laboratory and ex-vivo environments.The proposed solutions and techniques improve the autonomy level of robotic colonoscopes and reduce user workloads, which promotes the development and clinical translation of robotic colonoscopy.