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  • Title/Summary/Keyword: 구동압력

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Development of Series Connectable Wheeled Robot Module (직렬연결이 가능한 소형 바퀴 로봇 모듈의 개발)

  • Kim, Na-Bin;Kim, Ye-Ji;Kim, Ji-Min;Hwang, Yun Mi;Bong, Jae-Hwan
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.5
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    • pp.941-948
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    • 2022
  • Disaster response robots are deployed to disaster sites where human access is difficult and dangerous. The disaster response robots explore the disaster sites prevent a structural collapse and perform lifesaving to minimize damage. It is difficult to operate robots in the disaster sites due to rough terrains where various obstacles are scattered, communication failures and invisible environments. In this paper, we developed a series connectable wheeled robot module. The series connectable wheeled robot module was developed into two types: an active driven robot module and a passive driven robot module. A wheeled robot was built by connecting the two active type robot modules and one passive type robot module. Two robot modules were connected by one DoF rotating joint, allowing the wheeled robot to avoid obstructions in a vertical direction. The wheeled robot performed driving and obstacle avoidance using only pressure sensors, which allows the wheeled robot operate in the invisible environment. An obstacle avoidance experiment was conducted to evaluate the performance of the wheeled robot consisting of two active driven wheeled robot modules and one passive driven wheeled robot module. The wheeled robot successfully avoided step-shaped obstacles with a maximum height of 80 mm in a time of 24.5 seconds using only a pressure sensors, which confirms that the wheeled robot possible to perform the driving and the obstacle avoidance in invisible environment.

Driving Characteristic of The Thin Type Ultrasonic Motor using Microcontroller (Microcontroller를 이용한 박형 초음파모터의 구동특성)

  • Jeong, Seong-Su;Jun, Ho-Ik;Chong, Hyon-Ho;Park, Tae-Gone
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.201-201
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    • 2008
  • 박형초음파모터의 구조는 그림 1(a) 와 같이 크로스형태의 앓은 스테이터에 윗면과 아랫면에 각각 8 개의 압전세라믹이 부착된 형태이다. 압전세라믹의 분극방향은 로터와 접촉하는 스테이터의 A, B, C, D 네 개의 타점에서 순차적인 타원변위가 생성되도록 결정된다. 유한요소해석프로그램인 ATILA 5.2.4를 사용하여 최적설계를 한 결과 폭 3[mm], 길이 18[mm], 두께 1.8[mm], Brass 재질, Mid surface clamp 조건에서 입력전압 18[Vrms] 일 때 0.3[μm]의 변위를 보였다. 최적설계된 모델을 제작하였고, 정확한 실험결과를 얻기 위해서 푸쉬풀게이지, x-y스테이지, rpm 메타, 토크게이지를 이용하여 실험테이블을 구성하였다. 그림 1(b) 는 마이크로컨트롤러를 이용한 구동 드라이버를 보여준다. 한 주기에서 1/4분주의 순차적인 네 개의 구형파를 생성하고, 이를 push-pull회로를 동하여 90도의 위상차가 나는 정현파를 생성하여 초음파 모터의 구동전원으로 사용한다. 엔코더와 AD 컨버터를 이용하여 정속도 운전을 위한 피드백 제어가 된다. 제안된 구동드라이버를 이용하여 측정한 결과, 구동 주파수 88.6[kHz], 입력전압 [40Vrms], preload 0.2 [N]에서 130 [rmp] 의 속도와 25 [gfcm] 의 토크특성을 보였다. 압력전압을 증가시킬수록 속도는 선형적인 증가를 보였고, 토크는 이와 반대로 감소하는 특성을 보였다. 피드백 제어회로가 없는 경우에는 preload 변화에 따른 극심한 속도 변화를 보였고, 피드백 제어를 하였을 경우에는 0.2~0.4[N]의 범위에서 정속도 운전이 가능함을 확인하였다. 기존의 주파수발생기와 파워 엠프를 이용한 구동장비와의 특성비교에서도 큰 차이를 보이지 않았으며, 장시간의 운전에도 안정적인 구동이 가능함을 확인하였다.

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Application of a Single-pulsatile Extracorporeal Life Support System for Extracorporeal Membrane Oxygenation -An experimental study - (단일 박동형 생명구조장치의 인공폐 적용 -실험연구-)

  • Kim, Tae-Sik;Sun, Kyung;Lee, Kyu-Baek;Park, Sung-Young;Hwang, Jae-Joon;Son, Ho-Sung;Kim, Kwang-Taik;Kim. Hyoung-Mook
    • Journal of Chest Surgery
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    • v.37 no.3
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    • pp.201-209
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    • 2004
  • Extracorporeal life support (ECLS) system is a device for respiratory and/or heart failure treatment, and there have been many trials for development and clinical application in the world. Currently, a non-pulsatile blood pump is a standard for ECLS system. Although a pulsatile blood pump is advantageous in physiologic aspects, high pressure generated in the circuits and resultant blood cell trauma remain major concerns which make one reluctant to use a pulsatile blood pump in artificial lung circuits containing a membrane oxygenator. The study was designed to evaluate the hypothesis that placement of a pressure-relieving compliance chamber between a pulsatile pump and a membrane oxygenator might reduce the above mentioned side effects while providing physiologic pulsatile blood flow. The study was performed in a canine model of oleic acid induced acute lung injury (N=16). The animals were divided into three groups according to the type of pump used and the presence of the compliance chamber, In group 1, a non-pulsatile centrifugal pump was used as a control (n=6). In group 2 (n=4), a single-pulsatile pump was used. In group 3 (n=6), a single-pulsatile pump equipped with a compliance chamber was used. The experimental model was a partial bypass between the right atrium and the aorta at a pump flow of 1.8∼2 L/min for 2 hours. The observed parameters were focused on hemodynamic changes, intra-circuit pressure, laboratory studies for blood profile, and the effect on blood cell trauma. In hemodynamics, the pulsatile group II & III generated higher arterial pulse pressure (47± 10 and 41 ± 9 mmHg) than the nonpulsatile group 1 (17 ± 7 mmHg, p<0.001). The intra-circuit pressure at membrane oxygenator were 222 ± 8 mmHg in group 1, 739 ± 35 mmHg in group 2, and 470 ± 17 mmHg in group 3 (p<0.001). At 2 hour bypass, arterial oxygen partial pressures were significantly higher in the pulsatile group 2 & 3 than in the non-pulsatile group 1 (77 ± 41 mmHg in group 1, 96 ± 48 mmHg in group 2, and 97 ± 25 mmHg in group 3: p<0.05). The levels of plasma free hemoglobin which was an indicator of blood cell trauma were lowest in group 1, highest in group 2, and significantly decreased in group 3 (55.7 ± 43.3, 162.8 ± 113.6, 82.5 ± 25.1 mg%, respectively; p<0.05). Other laboratory findings for blood profile were not different. The above results imply that the pulsatile blood pump is beneficial in oxygenation while deleterious in the aspects to high pressure generation in the circuits and blood cell trauma. However, when a pressure-relieving compliance chamber is applied between the pulsatile pump and a membrane oxygenator, it can significantly reduce the high circuit pressure and result in low blood cell trauma.

The Performance Characteristics of Anti-Surge Devices for High Head Cooling Water Systems in 1,000 MW Thermal Power plants (고수두 1,000 MW 석탄화력발전소 냉각수계통 수격방지장치의 성능특성)

  • Kim, Keun-Pil;Yoo, Hoseon
    • Plant Journal
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    • v.15 no.4
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    • pp.36-42
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    • 2019
  • In recent, according to the tightening of environment regulation policy, the height of the site of the power plant is increased and the length of the cooling water pipe is increased. This has a serious impact on the stability of the plant. This study analyzes the transient phenomenon using LIQT 7.2, an unsteady state one-dimensional analysis software, to secure the stability of 1,000 MW high-capacity coal-fired power plant cooling water system with high head. To prevent water hammer, The effects on performance characteristics were predicted by individual and combination application. The surge pressure of the cooling water which occurs when the pump was stopped without installing the anti-surge devices was the largest at the pump outlet side. The most effective and simple way to reduce surge pressure in these cooling water systems is to combine a vacuum breaker with a hydraulic non-return valve, which is an essential device for pump protection.

Development of a Walking-type Solar Panel Cleaning Robot Capable of Driving on Inclined Solar Panel (경사진 패널 위에서 주행이 가능한 보행형 태양광 패널 청소로봇 시스템 개발)

  • Park, Sunggwan;Jang, Woojin;Kim, Dong-Hwan
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.5
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    • pp.79-88
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    • 2020
  • This paper propose the method to drive a solar panel cleaning robot efficiently on an inclined panel using vacuum pad pressure. In this method, the rubber pads using the vacuum pressure are used to attach robot body to the panel surface. By applying the linkage mechanism to the vacuum pads, it was possible to reduce robot weight and power consumption and to prevent slipping of the robot. In addition, the use of solenoid valves, proximity sensors, and encoders to detect movement of the robot body and the control of the pad pressure dedicate to the driving of the robot on an inclined panel. In order to move the robot forward, the operation sequence of multiple solenoid valves was completed, and the six vacuum pads mounted to both legs were accurately controlled to form vacuum and atmospheric pressure in right order so that the robot could move forward without slipping. At last, it was confirmed through experiments that straight-forward moving and rotational movement could be performed up to 36 degrees of inclination angle of solar panel.

The Secondary Chamber Pressure Characteristics of Sonic/Supersonic Ejector-Diffuser System (음속/초음속 이젝터 시스템의 2차정체실 압력특성)

  • 이준희;최보규;김희동;박종호
    • Journal of the Korean Society of Propulsion Engineers
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    • v.5 no.4
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    • pp.50-56
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    • 2001
  • The present study is an experimental work of the soni $c^ersonic air ejector-diffuser system. The pressure-time dependence in the secondary chamber of this ejector system is measured to investigate the steady operation of the ejector system. Six different primary nozzles of two sonic nozzles, two supersonic nozzles, petal nozzle, and lobed nozzle are employed to drive the ejector system at the conditions of different operating pressure ratios. Static pressures on the ejector-diffuser walls are to analyze the complicated flows occurring inside the system. The volume of the secondary chamber is changed to investigate the effect on the steady operation. the results obtained show that the volume of the secondary chamber does not affect the steady operation of the ejector-diffuser system but the time-dependent pressure in the secondary chamber is a strong function of the volume of the secondary chamber.er.

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Combustion Characteristics of a Gas Generator Associated with a Turbopump (터보펌프 연계상태의 가스발생기 연소 특성)

  • Seo, Seong-Hyeon;Ahn, Kyu-Bok;Han, Yeoung-Min;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.133-136
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    • 2008
  • The present study presents experimental results of combustion tests of a fuel-rich gas generator associated with a turbopump. Five combustion tests had been successfully executed. Static pressures of the gas generator promptly reacted to propellant supply variations from the turbopump. A closed-loop test for driving the turbopump revealed no flaw. Exit gas temperature results are very similar to previous ones. An orifice was effective on the suppression of pressure fluctuations although tests conducted below 45 bar showed the same dynamic behaviour as that of component-only tests.

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Modeling and Simulation of A Small Hydraulic Actuation System for the Tactical Missile (전술유도무기용 소형 유압식 구동장치의 모델링 및 시뮬레이션)

  • Lee, Doyun;Lee, Hosung;An, Sungyong;Park, Yeonjung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.4
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    • pp.349-357
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    • 2017
  • If an actuation system of the tactical missile is required very fast response time on conditions of short operating time and big loads on the actuator, we would prefer to adopt a small hydraulic system. In this paper, a mathematical model is proposed to analyze and simulate the small hydraulic actuation system. The mathematical model consists of a high pressure vessel model, a pressure regulator model, a hydraulic reservoir model and a actuator model. The suggested model is validated by comparison of simulation results with experimental data. The simulation results show that the mathematical model could be useful for designing a hydraulic actuation system.

Biomimetic Actuator and Sensor for Robot Hand (로봇 손용 인체모방형 구동기 및 센서)

  • Kim, Baek-Chul;Chung, Jinah;Cho, Hanjoung;Shin, Seunghoon;Lee, Hyongsuk;Moon, Hyungpil;Choi, Hyouk Ryeol;Koo, Jachoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.12
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    • pp.1497-1502
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    • 2012
  • To manufacture a robot hand that essentially mimics the functions of a human hand, it is necessary to develop flexible actuators and sensors. In this study, we propose the design, manufacture, and performance verification of flexible actuators and sensors based on Electro Active Polymer (EAP). EAP is fabricated as a type of film, and it moves with changes in the voltage because of contraction and expansion in the polymer film. Furthermore, if a force is applied to an EAP film, its thickness and effective area change, and therefore, the capacitance also changes. By using this mechanism, we produce capacitive actuators and sensors. In this study, we propose an EAP-based capacitive sensor and evaluate its use as a robot hand sensor.

Improved Control Algorithm Development for Control Element Drive Mechanism Control System (제어봉구동장치제어계통의 개선된 제어 알고리즘 개발)

  • Kim, Byeong-Moon;Lee, Young-Ryul;Han, Jae-Bok;You, Joon
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.761-765
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    • 1995
  • The old Timing Controller for Control Element Drive Mechanism (CEDM) is designed as an open loop control system because it is difficult to mount sensors within the Control Element Drive Mechanism(CEDM) which is operating under the pressure boundary of the reactor vessel. In this work new method which can be used to detect the CEDM operational conditions without mounting sensors within the CEDM housing is developed in order to resolve problems of the old Timing Controller. By using the developed new method, the new Timing Controller for the CEDM is designed as a closed loop controller which has features of the control rod drop prevention, fine position control and the coil life time extension. The algorithm developed under closed loop control concept resolves most problems occurred in the old Timing Controller and improves the performance and reliability of the system. During designing and testing of the Timing Controller algorithm, the real time CEDM simulator developed here was used. And all functions of the developed algorithm were verified using CEDM simulator with the real data collected from the site. The results show that the Timing Controller performs its intended functions properly.

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