Jong-Oh Park

A ciliary motion based 8-legged walking micro robot using cast IPMC actuators

In this paper, we present a micro robot using IPMC (Ionic Polymer Metal Composite) actuators. The IPMC actuator usually has been fabricated with commercially available ion-exchange polymer with the typical thickness of 100-300 /spl mu/m. By the casting of liquid ion-exchange polymer solution, the thickness of the IPMC actuator could increase up to a few millimeters. Based on the casting method, we could achieve the IPMC actuator that has larger stiffness and produces more generative tip force than the IPMC actuator fabricated with the commercially available solid ion-exchange polymer. A ciliary type 8-legged micro robot using the casting based IPMC actuators is constructed. The ciliary type 8-legged micro robot is 6.5 cm in length and 4.2 cm in width, and 1.5 cm in height and the total weight is 4.4 g with the actuators installed. The IPMC actuators used in this robot have a dimension of 20 mm in length, 4 mm in width and 1.15 mm in thickness. The input voltage to the IPMC actuator is set to /spl plusmn/4 V and the frequencies to the IPMC actuator is varying from 0.2 Hz to 1.0 Hz; with the increment of 0.2 Hz. The walking speed of the micro robot is changed from 3 mm/min to 17 mm/min with the variation of the frequencies.

Undulatory tadpole robot (TadRob) using ionic polymer metal composite (IPMC) actuator

We have developed the wireless tadpole robot that has simple geometry, driven by low voltage and the undulatory fin-motion using IPMC(Ionic Polymer Metal Composite) actuator. Behavior of TadRob is tested and analyzed under various frequencies(1/spl sim/8 Hz) to find the correlation between actuator frequency and velocity of the robot. In addition, the robot velocity based on undulation motion and oscillation motion of the fin is compared to find the proper fin-motion in the viewpoint of. velocity efficiency for the robot. Also, steering capability is tested under variation of duty ratio. Based on experimental results, we can confirm that the velocity of TadRob can be controlled by changing frequency of input voltage and the steering angle can be increased with increasing the duty ratio.

Locomotive mechanism design and fabrication of biomimetic micro robot using shape memory alloy

Recently, micro robots have been applied in various industrial areas. Some of them are requested to be able to move in small space or rough environment that people cannot reach. It is necessary to have a capability to move at even overturned and adapt simple mechanism to fabricate it easily with small size. In this paper, a novel bio-mimetic micro robot with simple mechanism using shape memory alloy (SMA) is introduced to generate earthworm-like locomotive motion. There have been many kinds of mobile micro robot using the SMA. However, these actuators generally require electric cable for power supply, which might have an adverse effect on the mobility of the micro robot The proposed micro robot system is composed of an actuator with SMA spring and silicone bellows, wireless control system, wireless power supply (battery) and body frames. The robot is also analyzed to customize required specifications. After the design and experiment, we find out that the micro robot can move a wireless free motion and be fabricated easily. Like an earthworm, the robot can travel on uneven, slippery and flexible environment.

Evaluation of the critical stroke of an earthworm-like robot for capsule endoscopes

Abstract Recently, the capsule endoscope has been highlighted for the patients convenience and the possibility of application in the small intestine. However, the capsule endoscope has some limitations in obtaining an image of the digestive organ because its movement depends only on the peristaltic motion. In order to solve these problems, it is necessary to determine the locomotive mechanism of the capsule endoscope. Therefore, the present authors have already proposed an earthworm-like robot, which has a locomotive mechanism. However, this mechanism should be designed so that the earthworm-like robot has a larger stroke than the critical stroke required to perform motion inside the small intestine. In this study, therefore, not only is the modelling of the locomotive process based on a biomechanical study presented but also the movement of the earthworm-like robot in the small intestine is simulated. Through the simulation process, the variation in the critical stroke with regard to the elastic modulus of the mesentery is investigated. Finally, from an in vitro test of the proposed robot, it is found that the experimental result is very similar to that of the simulation. Consequently, the present work will provide guidelines for designing an earthworm-like robot for diagnosis of the small intestine.

A locomotive mechanism for a robotic colonoscope

The increasing trend towards low fiber, high fat diets is leading to increasing pathology in the colon. Colonoscopy is a dexterous skill for doctors to perform and the procedure is painful to the patient. In this paper, we propose a new and simple locomotive mechanism that can be propelled by elliptic motion of multi legs. It has several legs that have constant phase difference to each other and are disposed along the upper and lower ends of the body. In order to evaluate the performance of the locomotive mechanism, we carried out simulations of moving characteristics and experiments in several environments including the colon of a pig.

Design and fabrication of an integrated cell processor for single embryo cell manipulation

This paper presents an integrated cell processor for the automatic handling of individual embryo cells. The integrated processor can perform various functions such as cell transport, isolation, orientation, and immobilization. These functions are indispensable and frequently used for the manipulation of single cells, but can only be carried out by a skillful operator. The purpose of this study was the integration and automation of these functions for effective cell manipulation, using a MEMS approach. The isolation of a cell was performed using polypyrrole (PPy) valves in a microchannel into which cells were transported. The orientation of cells was controlled by electrorotation (ER), and the target cell was immobilized by suction from a microhole. All of these functions were seamlessly realized on a single chip. Excellent experimental results with mouse (B6CBA) embryo cells showed that this device could substitute for routine and cumbersome manual work. It is expected that the integrated chip will contribute significantly to faster and more reliable manipulation of cells.

Bio-Material Property Measurement System for Locomotive Mechanism in Gastro-Intestinal Tract

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.

Pressure Monitoring System in Gastro-Intestinal Tract

Diseases in the gastro-intestinal tract are on an increasing trend. In order to diagnose a patient, various signals of the digestive organ, such as temperature, pH, and pressure, can offer the helpful information. Among the above mentioned signals, we choose the pressure variation as a monitoring signal. The variation of a pressure signal of the gastro-intestinal tract can offer the information of a digestive trouble or some clues of the diseases. In this paper, a pressure monitoring system for the digestive organs of a living pig is presented. This is why a pig’s gastro-intestinal tract is very similar as human’s. This system concept is to transmit the measured biomedical signals from a transmitter in a living pig to a wireless receiver that is positioned out of body. The integrated solution includes the following parts: (1) the swallow type pressure capsule, (2) the receiving set consisting of a receiver, decoder box, and PC. The merit of the proposed system is that the monitoring system can supply the precise and repeatable pressure in the gastro-intestinal tract. In addition, the design of low power consumption enables it to keep sending reliable signals while the pressure capsule is working in the digestive organ. The subject of the study for the pressure monitoring system is in-vivo experiments for a living pig. We achieved the pressure tracings in digestive organs and verified the validity of system after several in-vivo tests using the pressure monitoring system.

Design and fabrication of a bio-material property measurement system

Recently, diseases in gastro-intestinal tract have drastically increased. As a result, endoscopic technologies are being developed to diagnose and treat these diseases. Biomaterial property is essential information to develop endoscopic devices especially capsule type endoscope. For the past decades, experiments to obtain material property of gastro-intestinal tract are performed on in-vitro state. Therefore, material properties of digestive organs are not in-vivo test result but in-vitro result. In this research, we design, develop, and fabricate a bio-material property measurement (BMPM) system. The measuring system consists of a probing device, tendon device and suction part. The probe measures the force transmitted from the biomaterial as the sensing module protrudes based on the tendon controls, while the suction device seizes the organ. By using the system, we can measure the local deformation force and the piercing force. The measured deformation and piercing force data can be used for the locomotive and clamping mechanism design of the capsule type endoscope. In order to evaluate the validity of the BMPM, we perform the operation in an esophagus, stomach and colon of a pig. In conclusion, we could measure each organs material properties under in-vitro state without dissection of digestive organs. Some in-vivo test results are expected to design endoscopic devices using the proposed BMPM system.

Active operator guidance using virtual environment in teleoperation

Most existing teleoperation systems use video information for an operator to manipulate a remote system, or partially with force information. But these remain merely as assisting information to human perception. A new concept is presented, active operator guidance (AOG), which is comprehensive concept of assisting as well as guiding tool for a human operator using a virtual environment from monitoring level (passive) up to human reaction level (active). Two case studies explain how to use such AOG in teleoperation. The results show that AOG is powerful tool for precise and vital teleoperation.