Bio-Material Property Measurement System for Locomotive Mechanism in Gastro-Intestinal Tract Jiwoon Kwon, Sukho Park*, Byungkyu Kim and Jong-Oh Park Microsystem Research Center Korea Institute of Science and Technology, KIST P.O.Box 131, Cheongryang, Seoul 130-650, Korea {jwhj0814, shpark, bkim }@kist.re.kr, jop@microsystem.re.kr Abstract - Recently, diseases in gastro-intestinal tract have drastically increased. As a result, endoscopic technologies are being developed to diagnose and treat these diseases. Bio- material property is essential information to develop endoscopic devices especially capsule type endoscope. Because the capsule endoscope is moved by the peristaltic motion, it has some limitations to get the image of the digestive organ. Therefore, locomotive mechanism for capsule is necessary. In order to develop the locomotive mechanism, the information of bio- material property is required. Especially, the friction force between capsule endoscope and the tissues of the gastro-intestinal tract is very important information. In this paper, we propose the bio-material property measuring system which can supply the information for the design of the locomotive mechanism. By using the proposed measuring system, we evaluate the effects of design parameters such as velocity, diameter size and shape of capsule endoscope that influence the friction force to the capsule endoscope to get the dominant parameters. As a result, we can offer the useful information to design the locomotive mechanism of the capsule endoscope. Index Terms - locomotion; earthworm-like robot; bio-material property; gastro-intestinal tract I. INTRODUCTION In recent years, endoscopic technologies have been developed since disease for digestive system of latest human body increases gradually. Among the endoscopic technologies, a capsule endoscope is highlighted for the patient’s convenience and the possibility of the application in the small intestine. Because the movement of the capsule endoscope only depends on the peristaltic motion, it has some limitations to get the image of the digestive organ. Therefore, the research of the capsule’s locomotion is necessary. As the basic study of the locomotive mechanism, the information of bio-material property is required. Especially, the friction force of the tissues of the gastro-intestinal tract is very important information. In the bio-material properties of the digestive organ, several researches have been reported, which may be summarized as follows: Y. C. Fung investigated mechanical property of living tissues through several animal researches [1]. Also, J. Rosen and B. Hannaford showed similar relationship between general visco-elastic material and living tissue [2], and intravascular property detectable device is proposed by Mitsutaka Tanimoto and Fumihito Arai [3]. However, the above mentioned bio-material property measurement systems supply the limited information that is closely dependant on the measuring system. Therefore, they could not supply the information in order to design the locomotive mechanism. On the other hand, the locomotion mechanisms in gastro- intestinal tract are proposed as follows: Firstly, rotating wheel has been the most conventional method for the robot locomotion [4]. In this case, the mobility is not sufficient because the wheel has disadvantage when the robot moves on uneven, slippery or flexible environments. Secondly, some of legged robot has been studied, but the mechanism is complex and hard to control [5][6]. In addition, the miniaturization of robots does not mean downsizing the existing macro technologies. In our previous work, we proposed the earthworm-like locomotive mechanism by using shape memory alloy (SMA) spring and silicone bellows [7]. This mechanism is simple and effective. Such mechanism enables the earthworm-like robot to move on any environments. Among the previous researches, we have decided that the earthworm-like locomotive mechanism is appropriate to the locomotion in the GI tract. In this paper, therefore, we propose the bio-material property measuring system which can supply the information for the design of the locomotive mechanism. By using the proposed measuring system, we can derive the dominant design variables and get the proper values of the variables. Therefore, the results of this test can offer the useful information to design the locomotive mechanism of the capsule endoscope. II. EARTHWORM-LIKE LOMOTIVE MECHANISM DESIGN IN GASTRO-ITESTINAL TRACT A. Earthworm’s Locomotion Firstly, the structure and the locomotive mechanism of the earthworm are shown in Fig. 1. An earthworm’s body is made of segments. On each segment, except the first and the last, Proceedings of the 2005 IEEE International Conference on Robotics and Automation Barcelona, Spain, April 2005 0-7803-8914-X/05/$20.00 ©2005 IEEE. 1315