• Tribology and Lubricants
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• 제15권3호
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• pp.278-286
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• 1999

To predict the behavior of the intravascular micro active endoscope in the real human vascular system, a human mock circulation system was developed. The intravascular micro active endoscope which consists of micro active bending catheter and micro drug infusion catheter was driven in the velocity, Re number and temperature controlled flow. The three SMA (Shape Memory Alloy) zigzag type spring in the micro active bending catheter was heated by the electric current generated by PWM controller, and the shape memory effect made the actuator bend to any direction. The micro drug infusion catheter was driven through the inner hole of the micro active bending catheter. A mock circulation system is shaped from Ascending Arota to Femoral artery according to a human data (the data contains many vascular sizes and hydrographs of many control points). We developed a vascular model with glass and silicone tubes, and set the flow system with circulation parts, flow settling parts, and lots of valves. The heater and heat-controller was added to the How system to centre! the temperature of the How at 36.5$^{\circ}C$. The result showed that the developed intravascular micro active endoscope could be induced to any point in the vascular model.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.15-22
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• 1999

This paper demonstrates the feasibility of Shape Memory Alloy (SMA) actuators in controlling the motion of micro active catheter. The dynamic behavior of SMA is obtained by several experiments for the design of the controller. With the control parameters obtained in experiments, temperature feedback control algorithm is proposed and realized. The prototype of micro active catheter is fabricated, and its control performance which uses the designed controller is investigated. The results obtained show the potential of the SMA as viable means for actuating the micro active catheter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.761-764
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• 1995

This paper demonstrates the feasibility of utilizing Shape Memory Alloy(SMA) actuators in controlling the motion of micro active catherer. The dynamic behavior of SMA is obtained by several experiments for the design of the controller. Two different type of structures which realize catheter are proposed. Each prototype of micro active catherer is fabricated, and its control performance which used the designed controller is investigated. The results obtained show the potential of the SMA as viable means for actuating the micro active catheter.

• Tribology and Lubricants
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• 제15권3호
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• pp.272-277
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• 1999

The objective of this investigation is to examine the influence of the micro catheters, which mimic the intravascular micro active endoscopes, on local pressure changes and flow rate in an arterial branch model similar to the femoral artery of human. The effects of branch to main lumen flow rate ratios and the locations of a catheter tip were found to be significant on the local pressure changes. Relatively large pressure drops and an increase in shear stress due to the obstruction effects may induce an endothelial cell damage and a change in arterial wall permeability, which have been reported to be the primary cause of the initiation of the atherosclerosis and other major vascular diseases.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.72-75
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• 2000

This paper presents a simulation study on the description of the motion and the control of an active catheter actuator with multi-link structure actuated by Shape Memory Alloy(SMA). The model of an active catheter adopted in this paper has 3 links, and the individual links are composed of 3 micro coils of SMA for the omni-directional motion. In order to analyze the motions of multi-link structure, 3-dimensional kinematics description is presented. Also, the motion control of the end point of an active catheter using simple Neural Network is shown based on GUI(Graphic User Interface) system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.615-617
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• 1997

This paper reports experimental results on the fabrication and analysis of millimeter-sized bending actuators for active catheter by use of the shape memory alloy spring and the flexible beam. The major components of micro actuator are shape memory alloy spring, stainless steel strip and two acryl links. The micro actuator with the diameter of 2.0 mm and the length of 25 mm has been fabricated and characterized for the possible application to the micro active catheters. The measured maximum angle is $60^{\circ}$ and the response time is 5 sec.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.62-71
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• 1999

Integrating micro-machined sensors and actuators on the conventional devices with the copper power lines was incompatible to fabricate the mass produced micro electromechanical system (MEMS) devices. To achieve the compatibility of the wiring method between MEMS parts and devices, we developed the three-dimensional sputter-evaporation system that coats micropatterned thin copper films on the surface of the MEMS element. The system consists of a process chamber, two branch chambers, the substrate holder, and a linear-rotary motion feedthrough. Thin copper film was sputtered and evaporated on the biocompatible polymer, Pellethane$^{circed{R}}$ and silicone, catheter that is 2 mm in diameter and 700 mm in length. The metal film coating technique with three-dimensional thin film sputter-evaporation system was developed to apply the power and signal lines on the micro active endoscope. In this paper, we developed the three-dimensional metal film sputter-evaporation system operated on the low temperature for the biopolymeric substrates used in the medical MEMS devices.

• Journal of Information Technology Applications and Management
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• 제28권1호
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• pp.63-81
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• 2021

The advent of the convergence era led to the convergence of industries while increasing the uncertainty of R&D. R&D uncertainty can be addressed by identifying and addressing industrial innovation patterns, which Neo-Schumpeterian suggested can be identified through the process of identifying the technical characteristics of a particular industry, which can be embodied in the concept of technology trajectory. Thus, this study considered and proposed a method to track the technology trajectory of the convergence industry through topic modeling and patent citation network analysis, and applied it to the micro medical robot industry, which is a representative convergence industry, to track the technology trajectory of active catheter. In particular, it is intended to identify the unique characteristics of the industry by identifying the industry before the promotion of the national-led medical robot industry support policy. Therefore, we tried to understand the innovation pattern of the industry by tracking the technology trajectory of the industry before 2017, the time of full-scale support for the medical robot industry in the United States. Through tracking technology trajectories, the role of each technology classification, the development path, and the knowledge flow between applicants were analyzed empirically. The results of this study are expected to contribute to resolving the remaining uncertainties in the process of establishing an active catheter R&D strategy, one of the leading convergence industries, and furthermore, it is expected to be available for tracking technology trajectories in other industries.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2512-2514
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• 1998

The bending actuator using zigzag type shape memory alloy springs has been fabricated and characterized. The small sized actuator with outer diameter of 3.0mm and inner diameter of 2.0mm could be implemented because zigzag type spring has advantages for thin wall type actuator over the coil type spring. The measured characteristics of the fabricated bending actuator show the possibility of practical application to micro active bending catheter.