Design and fabrication of a locomotive mechanism for capsule-type endoscopes using shape memory alloys (SMAs)
Design and fabrication of a locomotive mechanism for capsule-type endoscopes using shape memory alloys (SMAs)
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DOI：
10.1109/tmech.2004.842222
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发表时间：
2005-02-01
影响因子：
6.4
通讯作者：
Park, JO
中科院分区：
文献类型：
--
作者：
Kim, B;Lee, S;Park, JO
内窥镜是诊断各种疾病的医疗设备，贯穿整个胃肠道。通常，它们分为传统的推式内窥镜和最近开发的无线胶囊式内窥镜。传统的内窥镜不能到达小肠，并且由于患者身体的僵硬而对患者产生疼痛和不适。这种缺点在无线胶囊型内窥镜中不存在。然而，商业化的胶囊型内窥镜通过蠕动波（和重力）被动地移动，这使得医生不可能更彻底和主动地诊断他或她感兴趣的区域。为了解决这个问题的被动，机车机制提出了无线胶囊型内窥镜。微型无刷直流电机，离子聚合物金属复合材料驱动器，和形状记忆合金（SMA）线的原型设计和制造的初步测试。在试验的基础上，选择了弹簧型SMA驱动器作为胶囊内窥镜的微驱动器。因此，双向线性驱动器使用一对SMA弹簧的基础上，他们的静态分析。此外，一个简单而有效的夹紧装置，开发基于仿生的方法。研制了一种具有四对SMA弹簧和四个夹持器的原型内窥镜。它的直径为13 mm，总长度为33 mm，具有直径为7.6 mm的中空空间，以容纳内窥镜检查所需的其他部件，例如摄像头，RF模块，传感器，内窥镜超声波和电池四个致动器的顺序控制将运动效率提高了四倍。为了验证所提出的运动机制的性能，进行了一系列的实验，包括在体外测试。实验结果表明，所提出的运动机构是有效的，用于微胶囊型内窥镜。
Endoscopes are medical devices to diagnose various kinds of diseases throughout the whole gastrointestinal tracks. Generally, they are divided into conventional push-type endoscopes and more recently developed wireless capsule-type endoscopes. The conventional endoscopes cannot reach the small intestines and generate pain and discomfort to patients due to the stiffness of their body. Such disadvantages do not exist in wireless capsule-type endoscopes. However, commercialized capsule-type endoscopes move passively by peristaltic waves (and the gravity), which makes it impossible for doctors to diagnose the areas of his or her interest more thoroughly and actively. To address this problem of passivity, a locomotive mechanism is proposed for wireless capsule-type endoscopes. Prototypes with micro brushless dc motors, ionic polymer metal composite actuator, and shape memory alloy (SMA) wires are designed and fabricated for preliminary tests. Based on the tests, spring-type SMA actuators are selected to be microactuators for capsule endoscopes. Thus, two-way linear actuators using a pair of SMA springs are developed based on a static analysis on them. Moreover, a simple and effective clamping device is developed based on biomimetic approach. A prototype endoscope with four pairs of SMA springs and four clampers was developed. It has 13 mm in diameter and 33 mm in total length, with a hollow space of 7.6 mm in diameter to house other parts that are needed for endoscopy such as a camera, an RF module, sensors, e.g., for endoscopic ultrasound, and a battery. A sequential control of the four actuators improves the efficiency of locomotion up to four times. To validate the performance of the proposed locomotive mechanism, a series of experiments were carried out including in-vitro tests. The results of the experiments indicate that the proposed locomotion mechanism is effective to be used for micro capsule-type endoscopes.