• Journal of Biosystems Engineering
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• v.27 no.3
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• pp.211-218
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• 2002

배추 생산에 있어서 수확, 운반, 적재 작업은 가장 노동이 집약적으로 요구되는 작업들이다. 최근, 여러 종류의 양배추 수화기가 일본과 유럽에서 개발되었다. 하지만 국내에서 재래되는 배추는 크기와 형태에 있어 양배추와는 달라 기 개발 기종의 도입이 어렵다. 또한 수확작업의 생력화 효과는 운반, 정선, 적재 작업과 밀접하게 연계되어 있어 출하시의 작업체계를 고려하여 수화에 따른 수집.반출 시스템을 개발하여야 한다. 수확시의 배추는 중량이 25~45 N 정도로 다 작물에 비하여 무겁고 부피가 크기 때문에 수확작업의 기계화를 위해서는 수확장치와 더불어 연속적으로 수확되는 배추를 적절하게 수집하여 적재하고 반출하는 시스템의 개발이 중요하다. 본 연구에서는 수확작업의 생력화 효과를 높이고 생력화 시스템 비용의 절감을 목적으로 작업자 1인에 의해 작업할 수 있는 반자동 형태의 트랙터 부착형 배추 수집, 적재, 반출시스템 시작기를 개발하였다. 시작기는 배추 이송장치, 적재장치, 팔렛 및 반출장치의 3개 부분과 PLC를 이용한 주 제어기로 구성하였다. 배추 수집용기로는 대략 70개의 배추를 담을 수 있는 크기가 1,050 mm$\times$1.050mm$\times$1,000mm 인 접이식 메쉬 팔렛을 사용하였으며 하단부에 롤러 안내판을 부착하여 적재한 팔렛의 배출이 용이하도록 하였다. 팔렛을 제외한 전체 시작기의 중량은 235 N 이였으며 크기는 3,940mm$\times$520mm$\times$1,630mm 이었다. 본 연구는 수확장치의 기능 및 생력화 효과를 극대화하고 배추의 손상정도를 최소화하는 시스템을 구성하고자 하였다. 이송장치는 트랙터 부착시 횡공간 점유율을 최소화하도록 하였으며 적재장치는 적재시 배추의 손상을 줄이고 배추가 놓이는 자세를 능동적으로 조절할 수 있도록 주름관을 부착하였다. 시작기의 실내시험 결과 이송장치는 0.18 m/s~0.36 m/s의 범위에서 적재장치는 0.4 m/s~2.4 m/s 범위에서 안정적으로 구동하였으며 두 장치를 동시에 구동하여 시험한 결과 이송장치는 0.26 m/s~0.36 m/s, 그리고 적재장치는 0.9 m/s~2.4 m/s 에서 적정하게 안정적으로 구동하였다. 적재장치의 성능에 있어서 1~3단 적재시에는 주름관을 이용하여 적재하고 4~5단 적재시에는 자유낙하에 의한 적재를 수행할 경우 인력에 의한 적재와 거의 동등한 적재량을 보였으며 손상정도는 거의 무시할 정도였다. 트랙터가 0.3 m/s로 주행하는 경우 노지로부터 배추를 뽑아 이송하는 뽑기벨트의 적정속도가 0.46 m/s인 점을 고려할 때 배추 이송 컨베이어는 0.34 m/s 이상의 속도를 유지할 필요가 있었으며 적재 컨베이어는 2 m/s~2.4 m/s의 속도에서 안정적으로 작동하였다. 배추의 주간 거리가 대략 30~40 cm 인 점을 감안하면 적재장치는 초당 1개의 적재성능을 보였다. 실내에서 수행한 시스템의 성능은 배추에 큰 손상없이 전반적으로 성공적으로 구동하였으나 향후 노면이 고르지 못한 포장에서의 성능 시험이 필요하다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.2
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• pp.63-70
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• 2003

In this paper, an MFC (Mass Flow Controller) which is widely used in many semiconductor manufacturing processes for controlling the mass flow rate of a gas is designed and implemented using the PIC 16F876 of Microchip, Inc. The MFC implemented in this thesis has the form of hybrid-type, i.e., the mixed-type of the analog-type MFC, which has many problems such as low accurary, and digital-type MFC, which use an expensive DSP (Digital Signal Processor) and an ADC (Analog to Digital Convertor) with high precision. The MFC is consists of the sensor unit, the control unit and the actuator unit, and it has used the automatic calibration algorithm and the reference table method for the improvement of the performance.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.173-181
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• 2016

This paper reports on the development of a roller-cam clutch mechanism. This mechanism can transfer bidirectional torque with high backdrivability, as well as increase actuation energy efficiency, in electrical exoskeleton robots. The developed mechanism was installed at the robot knee joint and unclutched during the swing phase which uses less metabolic energy, thereby functioning as a passive joint. The roller-cam clutch aimed to increase actuation energy efficiency while also producing high backdrivability by generating zero impedance for users during the swing phase. To develop the mechanism, mathematical modeling of the roller-cam clutch was conducted, with the design having more than three safety factors following optimization. Titanium (Ti-6AL-4V) material was used. Finally, modeling verification was done using ANSYS software.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.1
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• pp.8-14
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• 1998

This paper describes a novel real-time based optimal Pulse Width Modulation (PWM) method suitable for microprocessor-based PWM inverters. Optimal switching patterns minimizing the performance index corresponding to the distortion between the reference and the controlled output voltages are decided by on-line calculation using the microprocessor-implemented control system. To show the effectiveness of the proposed PWM scheme, digital simulation studies and experiments using a 16-bit single-chip microcontroller (Intel 80C196KC) are performed. The results obtained from these simulation studies and experiments show that the proposed PWM scheme has better performance than the other methods such as the natural PWM and the direct PWM.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.852-857
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• 2011

The shipbuilding industry needs automation and mechanization to solve reduction of skilled workers and labor shortage. Ship manufacturing process is the lack of automation than standardized manufacturing field. In this paper, we design and development an process automation system for hand rail production. Mechanical parts of the cutting process was designed with efficiency, productivity and reliability, CATIA and ANSYS, the stability of the mechanical structure was confirmed. System control using a PCNC controller to provide an open and scalable, and operate using touch-screen display control and monitoring of the system was performed. The automatic system successfully passed the driving test and processing test, and it showed an excellent performance.

• Journal of Biosystems Engineering
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• v.27 no.2
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• pp.97-106
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• 2002

이 연구는 채소의 생산에서 가장 많은 노동력이 소요되고 단순ㆍ반복적인 결속작업의 기계화기술을 개발하기 위하여 수행되었다. 본 논문은 이 연구의 제1보로서 채소의 결속작업실태를 조사분석하여 결속기의 개발방향을 설정하고, 채소의 이송 및 결속끈의 공급장치를 개발한 결과를 수록한 것이다. 채소의 결속작업은 철심이 내장된 끈을 사용하여 타원형으로 결속하고 있었으며, 작업자가 경험적으로 계량하여 결속된 단의 크기는 작물별 차이는 있으나 동일 작물에서 작업자간 차이는 없는 것으로 나타났다. 따라서 결속기는 작업자가 채소를 공급하면 일정 길이의 결속끈을 사용하여 타원형으로 결속하여 배출하는 방식으로 개발한 필요성이 있다고 생각된다. 이를 위해서 결속기는 작업자가 채소를 용이하게 공급할 수 있으며 결속장치까지 흐트러짐이 없이 이송하는 채소의 이송장치, 결속끈의 길이를 조절하여 공급하는 결속끈의 공급장치, 이송된 채소를 결속끈을 꼬아서 타원형으로 결속하는 결속장치 등으로 구성되어야 할 것이다. 채소의 이송장치는 작업자가 채소의 일정량을 용이하게 공급할 수 있도록 폭의 조절이 가능한 트레이를 체인콘베이어에 부착한 구조, 결속끈의 공급장치는 압축력이 걸려 있는 우레탄 재질의 구동 및 종동롤러로 원하는 길이의 결속끈을 피딩하면 칼날로 절단하는 구조로 개발하였다.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.351-358
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• 2000

This study was conducted to develop a speed control system of a DC motor which drove a barley seeder mounted on a combine harvester. Barley seeder mounted on a combine has been known to reduce labor and cost of barley cultivation. However, development of the seeder has been unsuccessful because the combine, a dedicated rice and barley harvester has not enough space and proper power take-off for barley seeder. To develop a barley seeder, small powered motor speed controller was required. A proximity sensor for detecting working speed of the combine and a programmable one board microprocessor was used to develope a control system. Motor parameters and motor constant, relationship between seeding rate, motor speed, groove volumes of a tested roller, torque were measured. The proximity sensor sent a frequency signal to the microprocessor. In laboratory experiments, the excitation voltage of the motor was shown not to be proportional to the size of pulse width (duty ratio). A table transforming frequency signal, that represented for working speed to proper pulse width was developed from seeding rate experiments. However, seeding rate at low frequency signal was not proportional to the working speed. Seeding rate control proportional to the frequency signal was achieved by shifting of the frequency signal.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.145-150
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• 2008

The objective of this research is to design the roller rig for the maintenances of high-speed train bogies operated on the tracks. Roller rigs have been studied and researched to develop the faster, safer and more efficient railway system. It is to reduce the time of testing vehicles and to make as wide a range of tests available as possible. Therefore, it is very important issue to check and evaluate the dynamic responses of high-speed train after several years of operation. This paper presents a study on the conceptual design and dynamic model to develop the roller rig for the routine maintenances of high-speed trains bogies with maximum speed of 350km/h. ANSYS was used to analyze the wheel/roller's contact behavior of driving axle and ADAMS was used to verify and analyze the dynamic behaviors of roller rig.

• Journal of the Korea Convergence Society
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• v.8 no.8
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• pp.77-82
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• 2017

In the splay manufacturing process, conveyor systems are widely used for conveying panels. In this conveyor, a large number of grounding lines are used in order to prevent a product failure due to static electricity. In many cases, the grounding line is disconnected due to the rotation of the transporting roller or curling, leading to product failure. In order to solve such a problem, there is a growing need for a system capable of detecting disconnection of a ground wire in real time. Therefore, in this paper, we propose a disconnection monitoring system of ESD (Electro-Static Discharge) ground wire caused by friction between the conveyor drive part and the panel. The proposed system is a monitoring system that can detect disconnection and disconnection of ground wire using ATmega 2560 and Wheatstone Bridge circuit. It can detect disconnection of ground wire immediately and can take measures to reduce the defect rate due to static electricity. The system proposed in this paper is expected to be applicable to the production and test equipments of all industries where the ground wire is used.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.525-535
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• 2004

In this paper, a two-phase DZRCD(Dual Zero Vector Modes RCD) technique is proposed to develope the problem of a conventional two-phase RCD-PWM (Random Centered Distribution PWM) which gives the power spectra of narrow band range in the high modulation index (M). In the proposed DZRCD technique, the zero vector $V_0$ is selected as $V_0$(111) for M$\geqq$0.8. Also, $V_0$ is selected as $V_0$(000) for the modulation indices < 0.8. For the unplementation of the proposed method, a 16-bit micro-controller Cl67 was used and the experiments were conducted with the 1.5kw induction motor under no load condition. The experimental results show that the voltage / current spectra is spread to a wide band range, and the switching noise of motor is reduced by the proposed method compared to the conventional random operation.