• Journal of Mechanical Science and Technology
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• v.20 no.7
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• pp.1012-1018
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• 2006

Diagnosis and treatment using the conventional flexible endoscope in gastro-intestinal tract are very common since advanced and instrumented endoscopes allow diagnosis and treatment by introducing the human body through natural orifices. However, the operation of endoscope is very labor intensive work and gives patients some pains. As an alternative, therefore, the capsule endoscope is developed for the diagnosis of digestive organs. Although the capsule endoscope has conveniences for diagnosis, it is passively moved by the peristaltic waves of gastro-intestinal tract and thus has some limitations for doctor to get the image of the organ and to diagnose more thoroughly. As a solution of these problems, various locomotive mechanisms for capsule endoscopes are introduced. In our proposed mechanism, the capsule-type microrobot has synchronized multiple legs that are actuated by a linear actuator and two mobile cylinders inside of the capsule. For the feasibility test of the proposed microrobot, a series of in-vitro experiments using small intestine without incision were carried out. From the experimental results, our proposed microrobot can advance along the 3D curved and sloped path with the velocity of about $3.29\sim6.26mm/sec$ and $35.1\sim66.7%$ of theoretical velocity. Finally, the proposed locomotive mechanism can be not only applicable to micro capsule endoscopes but also effective to advance inside of gastro-intestinal tract.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1669-1680
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• 2006

This paper explains that the RF systems for hi-directional wireless capsule endoscopes were designed and implemented. The designed RF systems for a capsule endoscope can transmit the images of intestines from the inside to the outside of a body and the behavior of the capsules can be controlled by an external controller simultaneously. The hi-directional wireless capsule endoscope consists of a CMOS image sensor, FPGA, LED, battery, DC to DC Converter, transmitter, receiver, and antennas. The transmitter and receiver which were used in the hi-directional capsule endoscope, were designed and fabricated with $10mm(diameter){\times}3.2mm(thickness)$ dimensions taking into the MPE, power consumption, system size, signal to noise ratio and modulation method. The RF systems designed and implemented for the hi-directional wireless capsule endoscopes system were verified by in-vivo experiments. As a result, the RF systems for the hi-directional wireless capsule endoscopes satisfied the design specifications.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.3
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• pp.80-85
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• 2008

Capsule endoscopes generally use primary cells as a power source due to its limited space. However, the primary cells have several limitations such as high cost, limited power and no reuse. To solve these problems, a new wireless energy transmission method is proposed. The proposed approach uses air-gap transformer concepts and LC resonance to transmit energy from transmitter(primary side) to capsule endoscopes(secondary side). The ferrite core with 3-axis winding is used to increase energy transfer efficiency regardless of direction and location. The experimental results show that the proposed method stably supplies 30mW power to secondary circuit.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.1 s.244
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• pp.84-89
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• 2006

A wireless capsule endoscope has been developed to replace the conventional endoscope. However, the commercialized capsule endoscope moves passively by peristaltic waves, which has some limitations for doctors to diagnose more thoroughly and actively. In order to solve this problem, a locomotive mechanism is proposed for wireless capsule endoscopes. Based on the tests of various actuators, a piezo actuator is selected as a micro actuator for capsule endoscope. In general, piezo actuators are known to have limited displacement with high voltage supply. In order to overcome the limitation of common piezo actuator, the impact based piezo actuator, is developed to realize long stroke up 11mm. By using the impact based piezo actuator, a prototype of an earthworm-like locomotive mechanism was developed. In addition, the proposed locomotive mechanism has engraved clamps mimicked the claw of an insect. The earthworm-like locomotive mechanism has 15 mm in diameter and 30mm under retraction stage and 41 mm under elongation stage in total length. Hollow space is allocated to comprise essential endoscope components such as a camera, a communication module, bio sensors, and a battery. For the feasibility test of proposed locomotive mechanism, a series of experiments were carried out including in-vitro tests. Based on results of the experiments, we conclude that the proposed locomotive mechanism is effective to be used for micro capsule endoscopes.

• The Journal of Korea Robotics Society
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• v.4 no.1
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• pp.62-67
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• 2009

For diagnoses of digestive organs, capsule endoscopes are widely used and offer valuable information without patient's discomfort. A general capsule endoscope which consists of image sensing module, telemetry module and battery is able to move along gastro-intestinal tracts passively only through peristaltic waves. Thus, it is likely to have some limitations for doctor to acquire images from the desired organs and to diagnose them effectively. As solutions to these problems, a locomotive function of capsule endoscopes has being developed. We have proposed a capsule-type microrobot with synchronized multiple legs. However, the proposed capsular microrobot also has some limitations, such as low speed in advancement, inconvenience to controlling the microrobot, lack of an image module, and deficiency in a steering module. In this paper, we will describe the limitations of the locomotive microrobot and propose solutions to the drawbacks. The solutions are applied to the capsular microrobot and evaluated by in-vitro tests. Based on the experimental results, we conclude that the proposed solutions are effective and appropriate for the locomotive microrobot to explore inside intestinal tracts.

• Journal of Magnetics
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• v.12 no.2
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• pp.89-92
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• 2007

The authors propose a magnetic actuator for use as a navigation system for capsule endoscopes. The actuator is composed of a capsule dummy, a permanent magnet inside the capsule, and an external spiral structure. The device rotates and propels wirelessly when exposed to an external rotational magnetic field. In this study we measured the effect of the spiral shape on the velocity and thrust force properties. According to our experimental results, the actuator obtained a maximum velocity and thrust force when the spiral angle was set at 45 degrees, the number of spirals was set at 4, and the spiral-height was set at 1-mmf. We also conducted a motion test in the large intestine of a pig placed on a 30 degrees slope. The actuator passed through a 700 mm length of the intestine in about 300 s. The device also managed to travel up and down the 30 degrees slope with no difficulty whatsoever. Our results demonstrate the great potential of this actuator for use as a navigation system for capsule endoscopes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.279-280
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.103-104
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• 2011

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1849-1855
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• 2003

Newly commercialized wireless capsule endoscope has many advantages compared to conventional push-type endoscopes. However, it is moved by the peristaltic waves. Therefore, it can not diagnose desired zones actively. In this paper, a locomotive mechanism for wireless capsule endoscope is proposed to increase the efficiency of endoscopy. We designed and fabricated a prototype using SMA springs and bio-mimetic clamping device. The hollow space in the prototype is allocated for further system integration of a camera module, a RF module and a battery. And the sequential control scheme is employed to improve the efficiency of its locomotion. To validate the performance of the locomotive mechanism, experiments on a silicone rubber pad and in vitro tests are carried out. The results of the experiments indicate that proposed mechanism is effective in harsh environments such as digestive organs of a human.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.57-63
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• 2005

Development of a locomotive mechanism fer the capsule type endoscopes will largely enhance the ability to diagnose disease of digestive organs. In connection with it, most of researches have focused on an installable locomotive mechanism in the capsule. In this paper, it is introduced that the movement of a capsule type endoscope in digestive organ can be manipulated by magnetic force produced outside human body. Since the magnetic force is provided by permanent magnets, no additional power supply to the capsule is required. Using a robotic manipulator for locating the external magnet, the capsule motion control system can cover the whole human digestive organs. This study is particularly concentrated on dither motion effect to improve the mobility of capsule type endoscope. It was experimentally found out that the friction coefficient between the capsule and digestive organ can be remarkably reduced by superposing yawing or rolling dither motion on the translatory motion. In this paper, the experimental results obtained with the direction, amplitude and frequency of sinusoidal dither motion changed is reported.