Endoscopic submucosal dissection (ESD) is a procedure targeted for early gastrointestinal cancer. Traction plays a crucial role in enhancing the efficiency of cutting lesions, thereby reducing procedural complexity and duration. From the perspective of traction devices, current non-magnetic ones hold shortcomings in complicating the workspace in directional tissue manipulation; Current magnetic traction devices cannot be prepared before the procedure, and require the withdrawal of endoscope in the midway to re-introduce the magnetic retractor to the lesion site. Towards these plights, this paper introduces a robotic flexible magnetic retractor designed for tissue manipulation during ESD. Precisely, the flexible prototype can be seamlessly inserted through the instrument channel of an endoscope to the lesion site without the need for endoscope withdrawal. Moreover, the introduction of robotic magnetic actuation enhances the agile control of magnetic retractors while alleviating the surgeon's workload in magnetic-retractor-assisted ESD. The experimental results validate the functionality and efficacy of the prototype magnetic retractor in magnetic traction-assisted ESD procedures. The retractor demonstrated its ability to provide adequate traction and accomplish clinical tasks. This innovative approach holds promise for enhancing the efficiency and outcomes of ESD procedures, offering a compelling alternative to traditional traction methods.

In response to torso-oriented magnetic localization tasks that require the system to have interactivity and flexibility with guaranteed accuracy, a novel bio-inspired magnetic sensor array configuration is proposed in this paper. Precisely, the ideas of the natural characteristics of octopus flexible tentacles and the "wrap" morphology are integrated into the design of the magnetic localization system based on the sensor array method. It is worth mentioning that such a design enhances the interactivity and flexibility of the localization system compared to the general planar sensor array strategy. Apart from the concept introduction, the geometry analysis of the proposed configuration is presented based on the constant curvature model. Besides, the magnetic localization algorithm for the system is presented by constructing a magnetic tracking optimization function. Eventually, the proposed concept and developed algorithm are examined in the sensor-array-simulation environment to manifest their effectiveness and applicability. The experimental results indicate that the octopus-inspired-configuration sensor array achieves a mean accuracy at a centimeter-level in our cases, and has better accuracy with a mean value of ē as 0.0178 m and ${\overline {SQR} _{ave{\text{ }}}}$ as 0.0883 for the center interest space compared to general planar configuration one. Moreover, the effect of the configuration error is analyzed. These results verify the feasibility and superiority of the proposed concept and hold significant practical significance in addressing the challenge associated with magnetic localization tasks toward the clinical application scenarios.

This paper is concerned with the issue of the kinematic model-based bending control for the magnetically actuated robotic endoscope and its application for automatic retroflexion. By the utilization of the Cosserat rod theory and the transformation in the magnetic tip of the endoscope, the comprehensive kinematic model of the magnetically-actuated robotic endoscope is established. Afterward, a magnetic control scheme for the bending motion is proposed by co-developing an error feedback PID control strategy and the model-based feedback approach. Moreover, as one unique kind of bending motion, retroflexion is taken into account, and the strategy aimed at the bid of compact space retroflexion is presented by virtue of the introduction of serial waypoints pursuing the position of the magnetic tip being close to the midline as possible. Eventually, the developed modeling and bending control scheme and the compact space retroflexion strategy are examined in a magnetically actuated robotic endoscope system to manifest the effectiveness and applicability of the theoretical approach. The experimental results indicate that the designed controller can drive the endoscope to bend to the desired pose and show a reduction of about 47.01% in the sweeping area and 79.25% in the last distance to midline achieved by conducting compact space retroflexion in comparison to “U” type one.

To solve the problems of discomfort and potential colon perforations of patients that arise when standard colonoscopes are used for colonoscopy, an electromagnetically actuated soft-tethered colonoscope robot (EASCR) is here introduced. Owing to EASCRs’ highly nonlinear and complex application environments, the hybrid vision/magnetic-force tracking control for these types of robots remains a challenging research issue, and the lack of current constraints may also give rise to safety concerns. Therefore, a hybrid vision/magnetic-force fast convergent dual neural network (DNN) tracking controller for an EASCR with current constraints is developed to alleviate patient discomfort and ensure the safe and smooth progression of colonoscopy. First, EASCR motion/vision and electromagnetically actuated force nonlinear coupling models are established, and a quadratic programming visual servo-tracking control scheme with current constraints is designed. Second, a novel DNN solver for the nonlinear control scheme is developed, and its convergence in finite time is strictly proved. The results of simulations and experiments indicate that the designed control method can well control EASCRs with current constraints to achieve tracking tasks, and it has a stronger anti-disturbance ability, faster convergence, and higher convergence accuracy than existing methods.

This paper presents a long-range magnetic actuated and guided endoscope for uniport video-assisted thoracic surgery (VATS). In VATS, the incision is quite narrow and part of the chest wall may be very thick. So, the magnetic endoscope system is required to produce sufficient attractive force at a considerable distance with a compact dimension. In this paper, a magnetic endoscope system is developed to meet the aforementioned clinical demands. In the system, both the internal and external units consist of two cylindrical magnets at both ends and a semi-cylindrical magnet in the middle. Coupled with the magnetic field from the external unit, the internal endoscope can achieve anchoring, tilting, panning, and translating to provide the desired view for the surgeon. The rotation of the endoscope is dynamically modeled by combining magnetic theory and coordinate transformation. The prototype is made with a boundary box of 10×14×56 mm, which can be inserted through the narrow incision in VATS. In the experiment, the developed models of anchoring, tilting, and panning were verified. The magnet configuration in the system can achieve a static anchoring distance of 95 mm and exhibits enhancement in attractive force compared with other designs.

Colorectal cancer incidence has been steadily rising worldwide. Magnetic colonoscopes provide new approaches to conduct colon inspection and treatment. This paper presents a novel electromagnetically actuated soft-tethered colonoscope to achieve precise and stable orientation control. An inflated balloon is designed to eliminate the unpredictable disturbance of the floating tether. A 2OR Pseudo-Rigid-Body (PRB) model of the soft tether is developed to analyze the relationship between the tether deflection and applied force and torque. A closed-loop control framework is constructed with visual position feedback. Experiments are first conducted to validate the assumption of the PRB model and the efficacy of the magnetic field model. Then, trajectory tracking tasks and disturbance rejection tests are performed to validate the feasibility of the proposed solution and closed-loop control. Results show that the colonoscope can stably and accurately orient to the desired orientation with an absolute mean position error of less than 0.5 mm and an average velocity of 3.5 mm/s. The distal tip can quickly re-stabilize to the desired orientation even when a large disturbance exists.

Crawling through various terrains has been a long research interest. In recent years, quite a number of soft crawling robots have been developed. However, locomoting in an elastic, humid, and slippery environment remains a challenge. In nature, gastropods, such as snails, live in humid environment and could crawl through all kinds of surface conditions by using wet adhesion. In the wet adhesive locomotion, the mucus is crucial in adhering the gastropod while allowing forward motion. Previously, we presented one snail-like soft robot that mimics the gastropods. In this work, we propose a second version and present a theoretical model of the mucus simulant. In addition, the dynamic model of the soft robot’s wet adhesive locomotion is developed for the first time. Results show that the speed of the current version is 5 times than that of the previous one through the optimization of design. Also shown by the results that the mucus helps to speed up the robot by at least 2.7 times.