• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.485-490
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• 2012

In this paper, driver circuit of LED lights for ships is designed and implemented to replace conventional lights with filament which have short life time due to vibration of ships. The driver of LED module is switching circuit without transformer to reduce volume and cost. As switch circuit controls input 220 VAC with PWM, LED module is reliably driven. Power factor is improved by using valley-fill PFC compensation circuit which is handled to pulse current of switching circuit. Serial-parallel LED circuit is applied to reduce change period of lights of long-term navigation ships. Array of serial-parallel can operate even if some of LEDs is damaged. It is suitable for ships that power consumption and power factor of lights including developed drive circuit have 39Watt and 0.925 respectively.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.1
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• pp.9-15
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• 2012

In this paper, the feasibility of a wheelchair carrier for the disabled own driver is checked kinematically to fit one of current domestic vans by drawings, design. A van with 9 passengers is selected for the modification to attach the wheelchair carrier and test the operation in real situation. The trajectory and motion process are studied to protect from the interception with outside body of van, and the conceptual design is proceeded kinematically. For the detail design, the stress analysis and driving mechanism with power supply must be studied and selected basically.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.595-597
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• 2008

자동반송 장비의 주행축에 적용되는 횡자속 선형전동기는 위치제어를 목적으로 한다. 위치제어는 자동 반송 장비가 최소구동시간에 최대의 생산을 할 수 있도록 성능이 우수한 구동프로파일을 사용하게 되는데, 어떤 종류의 구동 프로파일을 적용하느냐에 따라 시스템 전체의 응답 속도는 물론이고 진동과 소음을 최소화하여 전체 시스템의 성능을 좌우하게 된다. 일반적으로 사용되는 사다리꼴 속도 프로파일은 변화가 일정한 가감속 전류를 필요로 하고, 전체 구동시간이 짧아 간단한 시스템에 널리 사용되고 있지만, 가속의 끝점과 감속 구간의 시작점에서 급격한 속도 변화에 따른 져크(Jerk)가 발생하여 기구부에 충격이 가해지며, 이로 인한 진동과 소음을 유발해 순간적으로 큰 동적 에러를 발생시킨다. 따라서, 본 연구에서는 부드러운 속도 프로파일을 가지며 운동의 시작점과 끝점에서 '0'의 가속과 져크를 가지는 고차원의 구동 프로파일을 제시하고 횡자속 선형전동기에 적용하여 소음 특성을 분석하였다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.166-167
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• 2017

높은 효율과 긴 수명 등으로 형광등을 대체하며 차세대 조명기구로 각광받고 있는 LED 는 필수불가결적으로 PFC 및 DC-DC 컨버터 등으로 구성된 구동회로가 필요하다. 일반적으로 이러한 LED 구동회로의 조건으로 전체 90 % 이상의 고효율이 요구되고 있으나 Two-Stage 로 구성된 구동회로의 하드 스위칭에 따른 손실 및 기타 요건들에 의한 전력소모로 인해 실질적으로 완벽하게 조건을 달성하기 까다롭다. 최근에는 이러한 구동조건을 달성하기 위해 브릿지리스 PFC 컨버터를 적용한 Two-Stage 를 사용하거나 순환 전류 및 스위칭 손실이 보다 적은 LLC 공진 컨버터를 LED 용 구동회로에 접목하는 추세이다. 이에 따라서 본 논문은 LED 조명용 Single-stage LLC 공진 컨버터를 구성하여 동작특성을 분석하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.9-17
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• 2019

Variable guide vanes(VGVs) that consist of link mechanisms and an actuator system are required for an aircraft gas turbine engine to adjust the incidence angle of stator vanes. In this study, we developed a VGV actuator system for three-stage VGVs with two hydraulic actuators. The requirements for the actuator system were derived by analyzing the link mechanisms and air loads, and a hydraulic power-pack was developed based on these requirements. Through a load test using the actuator test-rig and the application of synchronizing control logic with proper control gains, the actuator system could be developed and verified.

• Journal of Drive and Control
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• v.13 no.4
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• pp.7-13
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• 2016

This paper presents the meter-out and meter-in speed control characteristics of a pneumatic cylinder with relief valve type cushion device. The piston displacement and velocity are measured to investigate high speed driving performance with variation of the pressure setting in relief valve, air supply pressure, load mass, the supply and exhaust flow rate from the cylinder. Also, the internal pressures and temperatures driving pressure and cushion chamber are measured. The piston displacements and velocities of meter-out and meter-in control are compared experimentally determined data. A comparison experimental data meter-out and meter-in control show that a relief valve type cushion device is suitable for high speed pneumatic cylinders. The desired response characteristics of piston displacement and velocity are satisfactory adjust the pressure setting of a relief valve with varying system parameters such as air supply pressure, load mass and controlled flow rate.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.476-481
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• 2001

In a vacuum circuit breaker mechanism, a spring-actuated linkage system is used to satisfy the desired opening and closing characteristics of electric contacts. Because the opening dynamics of electric contacts is determined by such a linkage system, the stiffness, free length and attachment points of a spring become the important design parameters. In this paper, based on the energy conservation that the total system energy is constant throughout the operating range of a mechanism, a systematic design procedure of determining the spring design parameters is presented. The proposed procedure is applied to the design of an opening spring for satisfying the specified opening characteristics.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.846-855
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• 1994

An effective stiffness, analogous to that of a wound spring, can be created by antagonistic redundant actuation of general closed-chain mechanisms. The qualitative and quantitative characteristics of the effective stiffness are investigated through a Four-bar mechanism, and a load distribution method is introduced which simultaneously guarantees the required system motion and the effective stiffness of the Four-bar mechanism. Furthermore, a simulation is performed to understand the inter-relationship among the effective stiffness, the Four-bar geometry, and the actuation effort. Based on this analysis, the Four-bar synthesis problem for effective stiffness generation is discussed.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.874-875
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• 2015

속도의 가변이 많지 않은 모터 application에서는 벡터 제어보다 홀센서를 사용한 BLDC제어를 주로 사용하고 있다. 하지만 기본적으로 홀센서의 기구적인 취약점으로 인하여 BLDC 제어에 문제점이 발생하는 현상을 확인할 수 있다. 본 논문에서는 기존의 BLDC전동기 구동에 필요한 3개의 홀센서를 이용한 전동기 구동방식에서 하나의 홀센서를 이용하여 회전자의 위치를 추정하는 방법에 대해 제안하였다. 이러한 방식을 통해 홀센서의 취약 부분인 열에 의해 손상되는 경우나 기구적으로 위치오차를 가지고 있는 경우에도 정상적으로 위치정보를 습득할 수 있도록 하여 정상적인 BLDC제어를 할 수 있도록 하는 방안을 제안하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.872-876
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• 1996

Most studies of rotary machinery design have been performed to establsih a new mechanism or a dramatic combination of machine elements for the power transmission. Although the rotary machine is worked very efficiently, that still has a major work to better performance which is the optimization of the selected mechanism for the mechanical efficiency, low vibration and noise, or customer interest. This work presents a practical approach used for washer's efficiency and machinery vibration and noise reduction along with a systematic procedure. Also for the confirming the study, a computer simulation program and a real working mock-up are developed and used to show very good agreement with the analytical result.