Research on driving force of capsule endoscope in fluid

The capsule endoscope (CE) is widely used in the inspection of digestive tract diseases. Due to the tortuosity and complexity of the intestinal tract, the CE is difficult to move during the intestinal examination. Therefore, establishing a reliable intestinal model to analyze the stress on the CE is very important. A fluid–structure coupling model of intestinal fluid and intestine was established to simulate the stresses of different shape CEs under a dynamic intestinal fluid environment. We analyzed the flow velocity distribution near the CE and the stress on the intestine in the horizontal and curved intestine environment. The relationship between the stress on the CE and the diameter of the intestine, the viscosity coefficient of the intestinal fluid, the elevation angle of the CE, and the shape of the CE head is studied. The results show that the stress on the head surface of the oval CE in the curved intestine (15.610 Pa) is greater than the stress on the head surface of the round CE (12.157 Pa). This research provides a basis for the design and structural optimization of the CE and provides more evidence for human intestinal examination and surgery.