• 수산해양기술연구
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• 제36권4호
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• pp.281-286
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• 2000

저층트롤 실물 어구를 이용한 해상 실험을 통하여 예망 중인 어구의 망구 형태에 관련되는 전개판의 간격 및 망고 등을 예망 속도별, 끌줄의 길이별로 측정하고, 이론적인 수치 해석 결과와 비교하여 실물어구의 수중 현황을 해석함으로서 어구의 효율적인 운용과 어획효과의 증대를 위한 기초자료를 제공하고자 한다. 수중 현황을 해석한 결과를 요약하면 다음과 같다. 1. 전개판의 전개간격은 예망 속도와 끌줄길이의 증가에 따라 직선적으로 증가하며 끌줄 길이에 의한 증가율이 예망 속도에 의한 증가율보다 현저히 크게 나타났으며, 그 간격의 변화는 57.0∼82.8m로서 후릿줄과 그물목줄 및 그물길이 전체의 43∼62%를 차지하였다. 2. 망구의 높이는 예망 속도와 끌줄길이의 증가에 따라 직선적으로 감소하며, 예망 속도에 의한 감소율이 끌줄 길이에 의한 감소율보다 현저히 크게 나타났는데 그 높이의 변화는 3.1∼4.0m로 나타났다. 3. 양 날개끝의 간격이 커지면 망고는 낮아지나 끌줄 길이가 증가할수록 날개 끝 간격의 증가에 대한 망구 높이 감소율의 비는 점차 작아졌다. 4. 망고에 대한 양 날개 끝 간격의 비는 예망속도와 끌줄 길이의 증가에 따라 점차 커졌는데, 그 비는 4.17∼7.81로 나타났다.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.89-94
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• 2006

The tire delivering power generated from engine to the ground pulls a vehicle to move. Radius of tires is changeable due to elasticity that depends on the speed of vehicle and traction force. The main objectives on this study are real time measurement of dynamic radius and slip ratio according to the speed and traction force. The dynamic radius is proportional to speed and traction force. According to measurement, the dynamic radius is increased about 3mm under 100km/h compared to stop. It is also increased about 1.5mm when a traction force is supplied as much as 4kN compared to no load state at low speed. There is no strong relationship between slip ratio and vehicle speed. The slip ratio is measured up to 4% under WOT at first stage gear. Through this research, the method of measuring dynamic radius and slip ratio is set up and is expected to be applied to the measurement of traction force in chassis dynamometer or accelerating and climbing ability.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.286-292
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• 1993

The classical way to improve the control performance is studied on the aspects of gun/turret deive systens. Two ways are discussed comparadively ; electrical case and electro-hydraulic case. System parameters are analytically studied in terms of resonance frequencies, and damping and gear train ratio effects are checked in relation to resonance frequency increase. Benefit of the feedback is discussed to increase the damping of the natural frequency lending to bandwidth increase.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.124-130
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• 1998

A mathematical model describing gear pump flow degradation in the presense of abrasive particles is presented. The model considers the operating parameters as Sommerfeld number, so that contamination sensitivity test results could be conversed to field application to predict contamination service life. A method to estimate the volumetric efficiency and the contamination level of a pump is proposed by measuring the temperature differences in the fluid. Test results show the validity of the theoretical establishments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.425-425
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• 2000

The heavy duty power manipulate generally has high ratio gear reducers at its joints. When it is used as a slave manipulator in the teleoperation system, therefore, the control input saturates frequently and its tracking performance and stability ate also likely to be deteriorated. This paper proposes a force reflecting control scheme for the manipulator with control input saturation. A series of experiments are shown to give excellent tracking performance with force reflection regardless of control input saturation.

• 연구논문집
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• 통권33호
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• pp.53-65
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• 2003

Electrostatic micro-motors can be divided into three classes: (i) salient type side drive motor, (ii) radial gap type wobble motor, (iii) axial gap type wobble motor. The working mechanism, torque evaluation, fabrication, and operational characteristics of each micro motors are compared. It is proved that axial gap type wobble motor has the bigger generating torque than that of the other type. The gear ratio of wobble motors increases the driving torque at the cost of a decreasing angular speed and decreases the friction because of the rolling motion instead of sliding at the bearing. Techniques for characterizing micro-motors performance are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2907-2909
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• 2000

This paper proposes a force reflecting and compliant control scheme for the heavy-duty power manipulators with high ratio gear reducers at its joints. From the experimental results. it can be seen that the proposed scheme has an excellent compliant force control performance.

• 드라이브 ㆍ 컨트롤
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• 제16권4호
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• pp.23-31
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• 2019

The purpose of this study was to evaluate the PTO severeness for an agricultural tractor during disk plow and rotary tillage. The PTO load measurement system was constructed with data acquisition and a PTO torquemeter. Field experiments were conducted at a combination of traveling speed (L3 Low, L3 High) and PTO speed (P1, P2). The load spectrum was generated using the rain-flow counting method, and the SWT method was used to consider the range and mean of the PTO load. The damage sum was calculated by applying a modified miner rule, which is a cumulative damage law. The relative severeness was expressed as the ratio of the lowest damage sum. Relative severeness was higher with the lower PTO gear stage, and higher driving gear stage and it was approximately 40-102 times higher for rotary tillage than disk plow tillage in the same gear stages. The relative severeness was 1010.12 in the rotary tillage under L3 High P1 based on the disk plow tillage under L3 Low P2.

• 수산해양기술연구
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• 제22권4호
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• pp.41-48
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• 1986

To investigate the midwater trawl gear available for the Korean near sea trawlers, the authors carried out a field experiment on the attitude and the opening efficiency of the otter board with the Pusan 404 (160GT, 750ps), a training ship of National Fisheries University of Pusan. The experimental trawl gear was designed to be operable by the ship and the otter board was made of single iron plate with 12% camber ratio. The special-prepared potentiometric angle detector was used for determining the attitude, and the 50 KHz fish finder for the opening between the otter boards. The results obtained can be summarized as follows: 1. The angle of attack varied by moving the towing point on the towing plate of the otter board. It showed 33 to 36 degrees when the point was set at the outmost position, 25 to 31 degrees at the middle position and 19 to 30 degrees at the inmost position, with a decreasing tendency according to the increase of towing speed in each cases. 2. The heel of the otter board always occured inwards, increasing slightly according to the increase of towing speed. 3. The tilt of the otter board always occured outwards, increasing slightly according to the move of the towing point inwards, and decreasing slightly according to the increase of towing speed. 4. The opening between otter boards showed the largest value when the towing point was set at the outmost position.

• 한국항공운항학회지
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• 제23권3호
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• pp.1-7
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• 2015

In the present study, we conducted the research on the high efficiency propulsion system for the development of long-endurance UAV with an electric propulsion system. For the long endurance UAV, fair aerodynamic characteristics with the high efficiency of the propulsion system is required because the flight power and the duration time of the long-endurance UAV vary greatly depending on the efficiency of the propulsion system. Therefore, in this study, the tracking program which records the performance of motor, propeller was developed because of their wide variation in the efficiency depending on the using condition, and records from the existing flight test program were utilized to check the accuracy of the program we had developed. For the development of future long-endurance solar UAV, we confirmed the applied voltage of motor, the optimal rotation of propeller and the gear ratio of reduction gear in order to get the highest efficiency on the propulsion system at the optimal flying condition.