• 로봇학회논문지
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• 제15권1호
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• pp.77-89
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• 2020

This paper proposes a simple and intuitive model-free torque-tracking control for rotary electro-hydraulic actuators. The undesirable natural-velocity-feedback effect is discussed by introducing mechanical impedance into the electro-hydraulic actuation system. The proposed model-free torque control comprises inner- and outer-loop control to achieve two control objectives. Inner-loop control reduces the mechanical impedance passively and optimally. To improve the tracking accuracy, a certain form of proportional-integral-derivative control is applied to the outer loop. The robustness of the proposed closed-loop system against external disturbances is demonstrated by transforming the two-loop control structure into a disturbance observer form. The proposed method is validated on a single joint electro-hydraulic actuator.

• 한국정밀공학회지
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• 제28권3호
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• pp.265-274
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• 2011

This paper presents current state of the prediction simulator of structural characteristics of machinery equipment accuracy. Developed accuracy prediction simulator proceeds and estimates the structural analysis between the designer and simulator through the internet for convenience of designer. 3D CAD model which is input to the accuracy prediction simulator would simplified by the process of removing the small hole, fillet and chamfer. And the structural surface joints would be presented as the spring elements and damping elements for the structural analysis. The structural analysis of machinery equipment joints, containing rotary motion unit, linear motion unit, mounting device and bolted joint, are presented using Finite Element Method and their experiment. Finally, a general method is presented to tune the static stiffness at a rotation joint considering the whole machinery equipment system by interactive use of Finite Element Method and static load experiment.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2000년도 추계공동학술대회논문집
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• pp.609-616
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• 2000

캐리어주식회사는 1985년 대우와 미국의 Carrier사가 50:50으로 설립한 Joint Venture로서 냉난방기 전문 제조 및 판매 회사이다. 1991년 미국 Carrier사가 85%의 지분을 확보함으로써 미국 Carrier사가 직접 경영을 하게 되었으며, 2000년에는 100% 지분을 확보하고 회사명도 대우캐리어주식회사에서 캐리어주식회사로 변경되었다 당사의 주요생산 품목은 룸 에어컨, 패키지 에어컨, Rotary Compressor 그리고 Chiller, AHU 등 System 제품이다. 공장은 광주광역시 하남공단에 위치하고 있으며 종업원은 약 1400명이다.(중략)

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.3207-3210
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• 2014

Background: Inflammatory breast cancer (IBC) is an aggressive form of locally advanced breast cancer characterized by rapidly progressive breast erythema, pain and tenderness, oedema and paeu d'orange appearance. It accounts for 1-3% of all newly diagnosed cases of breast cancer in the west. Data on IBC from India are lacking. The aim of our study was to assess the clinical-pathological parameters and outcome of IBC at, All India Institute of Medical Sciences, a large tertiary care centre. Materials and Methods: We screened 3,650 breast cancer cases registered from January 2004 to December 2012 and found 41 cases of IBC. Data included demographics as well as clinical, radiological and histopathological characteristics, and were collected from clinical case records using the International Classification of Diseases code (C-50). Patients who presented with IBC as a recurrence, or who had a neglected and advanced breast cancer that simulated an IBC were excluded from this study. Results: The median age was 45 years (range 23-66). The median duration of symptoms was 5 months. The American Joint Committee on Cancer stage (AJCC) distribution was Stage III - 26 and IV - 15 patients. Estrogen receptor (ER), progesterone receptor (PR) positivity and human epidermal growth factor receptor 2 (HER2/neu) positivity were 50%, 46% and 60%, respectively. Triple negativity was found in 15% of the cases. All the non metastatic IBC patients received anthracycline and/ or taxane based chemotherapy followed by modified radical mastectomy, radiotherapy and hormonal therapy as indicated. Pathological complete remission rate was 15%. At a median follow-up of 30 months, the 3 year relapse free survival and overall survival were 30% and 40%respectively. Conclusion: IBC constituted 1.1% of all breast cancer patients at our centre. One third of these had metastatic disease at presentation. Hormone positivity and Her2 neu positivity were found in 50% and 60% of the cases, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.593-596
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• 1997

The main purpose of this paper is to develop sensing device of joint angle using loss of opfical fiber. The source of light to optical fiber is infrared rays diode, and receiver is a photo transistor. The bent angle of optical fiber is measured with rotary encoder, and The change of voltage due to the loss of light is measured with micro computer PIC16C74. The sensing device may be used to Functional Electrical stimulation(FES) System for Rehabilitation patient.

• Ocean and Polar Research
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• 제39권4호
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• pp.293-300
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• 2017

Various approaches have been tried in an effort to improve the power performance of a flapping tidal stream turbine after it was introduced as an alternative to conventional rotary turbines. Among the different approaches, researches on mimicking the morphology and behavior of animals have been conducted. In this study, we utilized a flapper to mimic the multi-joint pectoral fin of a Manta-ray and investigated its effect on power generation. Experiments were conducted by a dual flapping apparatus with rigid and flexible flappers in a towing tank facility. First, in order to determine the conditions that can produce high power generation, the performances of the dual rigid flappers were compared when input arm angles and frequencies are changed, and the two conditions $40^{\circ}$, 0.2 Hz and $40^{\circ}$, 0.3 Hz for the input arm angle, frequency were selected. When the mimicked flexible flapper was used instead of the front rigid flapper and the rear one, the power was improved by an average of 22% and 38% in the experimental conditions, respectively. Moreover, it was recognized from the apparent camber observed during the experiment that the flexible flapper had been successfully applied. If the feasibility of the Manta-Ray mimicked flapper is improved through subsequent researches, the flapping tidal turbine can be a viable alternative to rotary turbines in the near future.

• 한국전산구조공학회논문집
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• 제36권3호
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• pp.165-171
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• 2023

건설기계와 특장차의 상부와 하부 구조를 연결하는 로터리 조인트는 축과 하우징이 회전하면서 유압을 전달하는데 오일의 유로에 누유를 방지하기 위해 여러 개의 시일이 조립된다. 시일재료는 강성이 커서 조립에 어려움이 있기 때문에 자른 후 조립하는 방법을 모색하였다. 절단면의 모양은 L형과 /형으로 하였고 유압이 작용할 때 누유 기준은 절단면에 발생하는 접촉압력으로 하였다. 시일의 구조와 재료는 이중 탄성중합체로 구성되며 강성이 큰 PE 재질만 절단한 경우에 대하여 비선형 접촉 구조해석을 수행하였다. 연구결과 절단 길이가 짧을수록 누유 방지에 유리하며 PE와 하우징이 접촉하는 윗면보다 NBR과 PE가 접촉하는 아랫면으로 누유될 가능성이 큰 것으로 나타났다.

• 한국정밀공학회지
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• 제31권7호
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• pp.643-649
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• 2014

In order to demonstrate the possibility of applying an ionic polymer metal composite (IPMC) to a finger exoskeleton, pinching motion analysis was performed for a thumb-index finger dummy actuated by IPMC actuators. The IPMC actuators of 5mm in width and 40mm in length with 2.4mm thickness generated 1.52N of blocking force for the applying voltage of 4.0V. Three actuators were installed on the three rotary joint of an index finger, and one actuator was installed on one proximal joint. Positions of each joint and finger tip were recorded on the video camera, and motion was analyzed. Power supply to the index finger actuators preceded power supply to the thumb actuator, and key pinching motion was accomplished in 180s. Tip pinching was accomplished in 135s as power supply to the thumb preceded power supply to the index finger.

• 한국정밀공학회지
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• 제15권12호
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• pp.142-147
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• 1998

Developing robot hands with multi-degree-of-freedom is one of the topics that researchers have recently begun to improve the limitation by adding flexibility and dexterity. In this study, an articulated servo-pneumatic robot hand system with direct-drive joints has been developed whose main feature is the minimization of the dimension. The servo-pneumatic system is advantageous to fabricate a dexterous robot hand system due to the high torque-to-weight and torque-to-volume ratio. This enables the design of a finger joint with an integrated rotary vane type actuator which produces high output torque without reduction gears, being very robust. In order to control the servo-pneumatic finger joints, a miniature proportional valve that can be attached to the robot hand is required. In this paper, a flapper nozzle type 4/3-way proportional directional valve has been designed and tested. The experimental results show that the developed valve can control a finger joint satisfactorily without much vibratory joint movements and acoustic noises.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.891-894
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• 2005

This paper describes a human finger model driven by shape memory alloy(SMA) wires. The finger model has three joints that are similar to human finger. Each joint is actuated with two wires in the antagonistic manner and six wires are used to actuate three finger joint. In order to obtain the desirable finger motion, the diameters of the SMA wires are designed with different diameters by considering the required actuating force and response time. The rotary sensors are used to measure the angle positions of the joints and PWM control using PID algorithm is used to achieve desired angle positions of the finger joints. After estimating the control performance of each finger joint for the desired angle position, the antagonistic motion control of the finger model is experimentally evaluated.