Capsule Robot Research Articles

A Chemical Reaction-Driven Untethered Volume Changing Robotic Capsule for Tissue Dilation

A Chemical Reaction-Driven Untethered Volume Changing Robotic Capsule for Tissue Dilation

Dynamic modeling and simulation of a new conceptual design of a magnetic capsule robot by application of endoscopic capsule

This paper investigates design, modeling, simulation, and dynamic issues related to self-propelled endoscopic capsule navigated inside the human body through external magnetic fields. A novel magnetic propulsion system is proposed and fabricated, which has great potential of being used in the field of noninvasive gastrointestinal endoscopy. The endoscopic capsule dynamic is studied on a medical silicone plate as the closest available material for the stomach tissue. First, the mechanical characteristics of the medical silicone plate is measured. Next, the forces acted on the endoscopic capsule which are friction, hydrodynamic and magnetic forces are determined by means of test and numerical techniques such as finite element method. Having known the magnitude of forces and torques on the endoscopic capsule, the dynamics of capsule are calculated under different initial conditions and external magnetic fields.

Exploiting reprogrammable nonlinear structural springs for enhancing the manoeuvrability of a vibro-impact capsule robot

Vibro-impact capsule robots, propelled by rhythmic collisions of an internal mass triggered by an external magnetic field, are emerging as promising tools for minimally invasive surgery. This innovative actuation mechanism allows for delicate interaction with tissues, making them ideal candidates for navigating confined surgical spaces. However, their limited manoeuvrability and controllability remain significant hurdles, restricting their ability to navigate complex anatomies and perform precise interventions, ultimately hindering their broader clinical applications. This paper investigates the integration of reprogrammable structural springs in capsule robots, demonstrating how dynamic tuning can tailor the interaction between the inner mass and the capsule, thereby unlocking enhanced manoeuvrability and precise control of the capsule robot. A mathematical model describing the dynamic response of a vibro-impact capsule robot integrated with von Mises trusses (VMT), which are used to tailor the interaction between the inner mass and the capsule, is developed and verified using finite element modelling. Using the verified mathematical model, we explore how the transition between mono-stability and bi-stability of VMTs affects the capsule robot’s propelling performance. Our findings demonstrate that this state switch enables four distinct propulsion modes of the capsule robot. This work paves the way for a new paradigm in small-scale robot design by incorporating reprogrammable nonlinear structures. These structures empower the robots with unprecedented manoeuvrability and controllability within a compact, deployable form factor.

Multimodal conversion of a magnetic navigated dual-hemisphere capsule robot based on self-standing characteristics

Multimodal conversion of a magnetic navigated dual-hemisphere capsule robot based on self-standing characteristics

Pose-Independent Interaction Distance Adjustment for Magnetically Driven Robotic Capsules

Pose-Independent Interaction Distance Adjustment for Magnetically Driven Robotic Capsules

Two-dimensional ferrite core-based transmitting coil for wireless power transfer in novel capsule robots

Two-dimensional ferrite core-based transmitting coil for wireless power transfer in novel capsule robots

Design and Experiment of 2D Rectangular Solenoid Transmitting Coil for Novel Gastrointestinal Capsule Robot

Design and Experiment of 2D Rectangular Solenoid Transmitting Coil for Novel Gastrointestinal Capsule Robot

A new industrially magnetic capsule MedRobot integrated with smart motion controller

Capsule medical robots with unique application advantages have broad prospects for gastrointestinal detection, targeted drug delivery, medical assistance, and other fields. However, due to the complexity of the gastrointestinal environment and the limitations of the space magnetic field, robust motion control of capsule robots is still a challenge. Using a permanent magnet (NdFeB) as a space magnetic source, a capsule robot manipulation instrument with an integrated motion intelligent control approach is proposed in this work. First of all, a steering fixture controlling a permanent magnet is designed, and a manipulation instrument capable of five degrees of motion freedom is built with low cost and high accuracy. Furthermore, an integrated motion control approach, consisting of a primary motion subsystem and an auxiliary motion subsystem, is presented, where the motion route of the capsule robot is planned. A parallel optimization strategy is adopted to improve the traditional Gray Wolf Optimization Algorithm, the improved version of which is utilized to tune the parameters of controllers. Finally, some experiments of the designed capsule robot are carried out in different planes and slopes, as well as simulated stomach and real pig stomach, respectively. The results show that the motion characteristics are continuous and stable, and the average position error is 4.2 mm, which meets the application requirements.

Multiple Sampling Capsule Robot for Studying Gut Microbiome

Longitudinal analysis of the gut microbiota is crucial for understanding its relationship with gastrointestinal (GI) diseases and advancing diagnostics and treatments. Most ingestible sampling devices move passively within the GI tract, rely on physiological factors, and fail at multipoint sampling. This study proposes a multiple‐sampling capsule robot capable of collecting gut microbiota from various locations within the GI tract with minimal cross‐contamination. The proposed capsule comprises a body, a driving unit, six sampling tools, a central rod, and two heads. Electromagnetic field control facilitates control of the orientation and position of the capsule, particularly to align the channel of the capsule where the sample is collected facing downward. The capsule can collect six gut microbiota samples preventing contamination before and after sampling. The active locomotion and multiple sampling performance of the capsule are evaluated through basic performance tests (propulsion direction precision: 0.76 ± 0.52°, channel alignment precision: 0.84 ± 0.55°), phantom tests (average amount per sample: 10.3 ± 2.4 mg, cross‐contamination: 0.6 ± 0.4%), and ex‐vivo tests (average amount per sample: 9.9 ± 1.7 mg). The possibility of integration and clinical application of the capsule is confirmed through preclinical tests using a porcine model.

Optimization of Wireless Power Receiving Coil for Near-Infrared Capsule Robot

Optimization of Wireless Power Receiving Coil for Near-Infrared Capsule Robot

Enhancing the Mobility of Small-Scale Robots Via Nonlinear Structural Springs Exhibiting Negative Stiffness

Abstract Compared to traditional robotic systems, small-scale robots, ranging from several millimeters to micrometres in size, are capable of reaching narrower and vulnerable regions with minimal damage. However, conventional small-scale robots’ limited maneuverability and controlability hinder their ability to effectively navigate in the intricate environments, such as the gastrointestinal tract. Self-propelled capsule robots driven by vibrations and impacts emerge as a promising solution, holding the potentials to enhance diagnostic accuracy, enable targeted drug delivery, and alleviate patient discomfort during gastrointestinal endoscopic procedures. This paper builds upon our previous work on self-propelled capsule robots, exploring the potential of nonlinear connecting springs to enhance its propulsion capabilities. Leveraging a mathematical model for self-propelling robots with a von Mises truss spring, which is verified using a finite element model, we investigate the effects of negative stiffness and snap-back within the nonlinear structural spring on the robots’ propelling speed. Our analysis reveals that the negative stiffness of the von Mises truss can significantly reduce the sensitivity of the propelling speed to excitation frequency. As a result, the capsule robot exhibits a remarkably wider operational band where it maintains a high average propelling speed, surpassing its linear counterpart. This work sheds light on the potential for developing customized nonlinear structural systems for diverse scenarios in small-scale robot applications, opening up new possibilities for enhanced functionality and maneuverability in various biomedical applications.

Magnetically Driven Biopsy Capsule Robot with Spring Mechanism.

In recent years, capsule endoscopes (CEs) have appeared as an advanced technology for the diagnosis of gastrointestinal diseases. However, only capturing the images limits the advanced diagnostic procedures and so on in CE's applications. Herein, considering other extended functions like tissue sampling, a novel wireless biopsy CE has been presented employing active locomotion. Two permanent magnets (PMs) have been placed into the robots, which control the actuation of the capsule robot (CR) and biopsy mechanism by employing an external electromagnetic actuation (EMA) system. A spring has been attached to the biopsy mechanism to retract the biopsy tool after tissue collection. A camera module has also been attached to the front side of the CR to detect the target point and observe the biopsy process on the lesion. A prototype of CR was fabricated with a diameter of 12 mm and a length of 32 mm. A spring mechanism with a biopsy needle was placed inside the CR and sprang out around 5 mm. An in vitro experiment was conducted, which demonstrated the precise control translation (2 mm/s and 3 mm/s in the x and y directions, respectively) and desired extrusion of the biopsy mechanism (~5 mm) for sampling the tissue. A needle-based biopsy capsule robot (NBBCR) has been designed to perform the desired controlled locomotion and biopsy function by external force. This proposed active locomoted untethered NBBCR can be wirelessly controlled to perform extended function precisely, advancing the intestinal CE technique for clinical applications.

Modeling and Experimental Validation of Anchoring Resistance of the Radial Expanding Capsule Robot in the Intestine

Modeling and Experimental Validation of Anchoring Resistance of the Radial Expanding Capsule Robot in the Intestine

A new capsule-intestine model for the capsule robot self-propelling in the lower gastrointestinal tract

Circular and haustral folds in the lower gastrointestinal tract (small and large intestines) are the major obstructions impeding the locomotion of the capsule robots for endoscopic diagnosis. Understanding the interactions between the capsule and these folds is critical for design and control of these robots to reach the areas of clinical interest. This paper proposes a new mathematical model of capsule-intestine interaction based on our previous work (Yan et al. 2022) by introducing capsule’s rotation during fold crossing. The resisting force of the fold predicted by the new model is more consistent with our finite element and experimental results compared to our previous model. It is found that the obstructive effect of the fold is stronger for a higher and thinner fold with a thinner and stiffer intestine. For the capsule robot, which is actuated by a periodically driven inner mass, a stronger excitation force is required to overcome the fold with a larger resisting force. Moreover, our bifurcation analysis reveals that a small excitation force always incurs a simple period-1 motion for the robot, while a large excitation force may result in various complex dynamics before the fold crossing. The findings of this work may help capsule robotics engineers to evaluate their designs in terms of propulsion and understand the locomotion of their robots in the lower gastrointestinal tract.

Characterizing the Coefficient of Friction Between a Capsule Robot and the Colon.

A capsule robot (CR) with an onboard active locomotion mechanism, has been developed as a promising alternative to colonoscopy due to its minimally-invasive advantage. Predicting the traction force and locomotion resistance of the CR, which are both the friction force, is significantly important for the CR development and control. However, a comprehensive study concerning the coefficient of friction (COF) in the colon, which is necessary for prediction, is not available in literature. This paper is dedicated to determining a quantitative COF equation in terms of the contact pressure, hoop strain, and sliding velocity. The COFs of three commonly-used materials of the CR (i.e., PDMS, white and transparent ABS plastic), are measured under 144 different friction cases (6 contact pressures×4 hoop strains×6 sliding velocities). By analyzing the measurements, the influence law of the three factors on the COFs of the three materials is revealed, and based on which, a general COF equation involving eight fitted constants is determined. The determination coefficients of the COF equation for the three materials are up to 0.9822, 0.9286, and 0.9696, respectively. The COF equation is used to predict the traction force and locomotion resistance of a crawler CR, and the predicting results fit well with the measured ones. The COF equation can provide a correct COF for friction force prediction. It is promising to enable a better force and locomotion control for the CR in the colon.

Design and Optimization of a Novel Double-Layer Helmholtz Coil for Wirelessly Powering a Capsule Robot

Design and Optimization of a Novel Double-Layer Helmholtz Coil for Wirelessly Powering a Capsule Robot

Design and Control of a Miniaturized Magnetic-Driven Deformable Capsule Robot for Targeted Drug Delivery

Design and Control of a Miniaturized Magnetic-Driven Deformable Capsule Robot for Targeted Drug Delivery

Magnetic Localization Algorithm of Capsule Robot Based on BP Neural Network

Magnetic Localization Algorithm of Capsule Robot Based on BP Neural Network

A Magnetic Capsule Robot with an Exoskeleton to Withstand Esophageal Pressure and Delivery Drug in Stomach

A Magnetic Capsule Robot with an Exoskeleton to Withstand Esophageal Pressure and Delivery Drug in Stomach

Enhanced Localization Strategy for Magnetic Capsule Robot Using On-Board Nine-Axis IMU Through Incorporation of Alternating Magnetic Field

Enhanced Localization Strategy for Magnetic Capsule Robot Using On-Board Nine-Axis IMU Through Incorporation of Alternating Magnetic Field