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In previous works, when studying the frictional behaviour of the small intestine, the small intestine was always in a natural state. However, when a capsule endoscope is travelling through the small intestine, since the diameter of the capsule endoscope may larger than the small intestine, the small intestine is then expanded in circumferential direction, which implies that previous works are not sufficient. This work uses flat–flat contact to simulate a capsule travelling through the small intestine, comparing the frictional behaviour of the small intestine in its natural and circumferentially expanding states, analysing the effects of other factors such as load, velocity and lubrication, which provides a realistic basis for the optimisation and control of magnetically controlled endoscopes. [ABSTRACT FROM AUTHOR]

An interventional robot is a means for vascular diagnosis and treatment, and it can perform dredging, releasing drug and operating. Normal hemodynamic indicators are a prerequisite for the application of interventional robots. The current hemodynamic research is limited to the absence of interventional devices or interventional devices in fixed positions. Considering the coupling effect of blood, vessels and robots, based on the bi-directional fluid–structure interaction, using the computational fluid dynamics and particle image velocimetry methods, combined with the sliding and moving mesh technologies, we theoretically and experimentally study the hemodynamic indicators such as blood flow lines, blood pressure, equivalent stress, deformation and wall shear stress of blood vessels when the robot precesses, rotates or does not intervene in the pulsating blood flow. The results show that the intervention of the robot increase the blood flow rate, blood pressure, equivalent stress and deformation of the vessels by 76.4%, 55.4%, 76.5%, and 346%, respectively. The operating mode of the robot during low-speed operation has little impact on the hemodynamic indicators. Using the methyl silicone oil as the experimental fluid, the elastic silicone pipe as the experimental pipe, and the intervention robot having a bioplastic outer shell, the velocity of the fluid around the robot is measured on the developed experimental device for fluid flow field in a pulsating flow when the robot runs. The experimental results are similar to the numerical results. Our work provides an important reference for the hemodynamic study and optimization of the mobile interventional devices. [ABSTRACT FROM AUTHOR]

In past studies, when modeling the resistance of magnetically controlled capsules traveling through the small intestine, the small intestine was usually assumed to be a straight tube with constant diameter. However, the small intestine is curved in most cases, which means that the intestine can no longer be simplified to be a straight tube with constant diameter, meaning that existing resistance models will no longer be applicable. In this paper, based on the assumption that intestine is curved, the resistance models of the capsule running in the curved intestine is established, and then it is validated experimentally. The model provides a realistic foundation for the optimization and control of the magnetically controlled endoscopy. [ABSTRACT FROM AUTHOR]