肠道驻留机构的设计和实验

Design and experiment of an intestinal anchoring mechanism

研究并设计了一种微型肠道驻留机构以实现胃肠道机器人在人体肠道特殊环境下的有效驻留.该驻留机构采用径向伸出三组腿的方式实现扩张,扩张后三组腿仍然处于封闭状态,从而有效降低了肠道组织被夹住的风险.对驻留机构与肠道之间的相互作用进行了建模分析,并将驻留机构的驻留力分为库伦摩擦力和边缘阻力两部分,分析了其产生机理.通过实验测试了驻留机构的扩张力以及驻留力.实验结果表明：驻留机构的扩张力与理论分析较为接近,驻留力大小与肠道直径、驻留腿扩张直径以及驻留机构速度有关.当驻留腿的扩张直径为20～26 mm时,驻留力大小为0.15～0.4N;当驻留腿扩张直径大于26 mm时,驻留力迅速增加,为0.5～1.8N.设计的肠道驻留机构体积小、安全,可较好地适应肠道的生理环境,并为肠道诊疗微型机器人驻留机构的设计提供了一种新的思路.

A miniature intestinal anchoring mechanism is designed to realize the effective anchor of a gastrointestinal robotic endoscope in the special environment of human intestine.The mechanism explores a kind of expansion method through protruding three sets of legs radially,which lowers the risk of intestinal clamping because the three sets of legs show a enclosed structure after expansion.At the terminal of every legs,a curved plate is fixed to enlarge the contacting area between legs and intestine,which reduces the damage to intestinal tract.The interaction between anchoring mechanism and intestinal tract is modeled.The anchoring force is divided into two parts,Coulomb friction and marginal resistance,and its mechanism is analyzed.The expanding force and anchoring force are tested through experiments.The experimental results show that the expanding force of the anchoring mechanism is close to the theoretical analysis,and the anchoring force is related to intestinal diameters,the expanding diameters of anchoring legs and the speed of the anchoring mechanism.When the diameters of the anchoring legs are 20-26 mm,the anchoring force is 0.15-0.4 N; when the diameters of anchoring legs are greater than 26 mm,the anchoring force increases rapidly between 0.5 N and 1.8 N.The anchoring mechanism proposed in this paper is characterized by safe and a smaller volume and is suitable for the physical environment of the intestine.It provides a new idea for design of the intestinal anchoring mechanism for micro robots in gastro intestinal tract diagnosis.