• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.932-938
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• 2009

As a stringing troy wire is installed by manual operation, it is necessary to scheme the automatic system for stringing troy wire. To accomplish a task of this kind, in this paper an approach to designing controllers for the hybrid Position/Tension control of a stringing troy wire is presented. Position control system is designed based on equation of dc motor and motion equation of robot, it is controlled by feedback with a detected speed dc motor. Tension control system is designed based on equation of ac servomotor for generating torque and dynamic equation of a troy wire, it is controled by feedback with a detected tension. The control parameters is determined by simulation in independence operation of each system. To suppress a mutual interference that the disturbance occur in operating of two task at same time. Dynamic hybrid control is proposed by feed forward compensator with a disturbance accelerator and a step torque at start. The operation of proposed system is simulated and experimented, results is verified the utilities.

• 대한조선학회논문집
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• 제29권4호
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• pp.146-151
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• 1992

이 논문에서는 스내핑 케이블(Snapping Cable)의 극단 인장력(Extreme Tension)이 연구되어지고 해석기법으로 클리핑-오프 모델(Clipping-off Model)을 이용하여 매개변수 연구(Parameter Study)가 수행되었다. 이 매개변수 연구에 의한 주어진 케이블의 초기 클리핑 발생 주파수 예측은 거친 해상에서 큰 동인장력(Large Dynamic Tension)이 발생되어 전체인장력(Total tension) 이 음의 값이 되는 스내핑현상이 일어날 수 있는 케이블의 동적 거동을 예견하기 위한 유용한 지침으로서 사용될 수 있을 것이다.

• Ocean Systems Engineering
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• 제8권3호
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• pp.345-360
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• 2018

Increasing demand for large-sized Floating, Storage and Regasification Units (FSRUs) for oil and gas industries led to the development of novel geometric form of Buoyant Leg Storage and Regasification Platform (BLSRP). Six buoyant legs support the deck and are placed symmetric with respect to wave direction. Circular deck is connected to buoyant legs using hinged joints, which restrain transfer of rotation from the legs to deck and vice-versa. Buoyant legs are connected to seabed using taut-moored system with high initial pretension, enabling rigid body motion in vertical plane. Encountered environmental loads induce dynamic tether tension variations, which in turn affect stability of the platform. Postulated failure cases, created by placing eccentric loads at different locations resulted in dynamic tether tension variation; chaotic nature of tension variation is also observed in few cases. A detailed numerical analysis is carried out for BLSRP using Mathieu equation of stability. Increase in the magnitude of eccentric load and its position influences fatigue life of tethers significantly. Fatigue life decreases with the increase in the amplitude of tension variation in tethers. Very low fatigue life of tethers under Mathieu instability proves the severity of instability.

• 대한기계학회논문집 C: 기술과 교육
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• 제3권2호
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• pp.89-96
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• 2015

Based on multi-body dynamic software RecurDyn, this paper proposes a modified form of timing silent chain system combing with the existing problem that vibration and chain tension is too large, which is applied for complicated conditions in a V-type engine, such as high speed, variable loads. The analysis of chain drive meshing characteristics is completed. Using the multi-body dynamic soft-ware RecurDyn, the dynamics characteristics of the improved system is studied, including chain tension, transmission error, chain fluctuations, equivalent spring force in different operating conditions. The study results show that chain tension, transmission error, chain fluctuation and equivalent spring force are within the scope of permission, all of them can meet the design requirement. There-fore, the design of this system is reasonable and practicable. The research results will provide a basis for assessing timing silent chain system in a V-type engine and a theoretical reference for designing and optimizing the timing silent chain system.

• 한국지진공학회논문집
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• 제18권5호
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• pp.253-259
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• 2014

Porcelain surge arrestor is very vulnerable to earthquake but there is very few information on its dynamic characteristics which are necessary to the seismic design. Therefore, the dynamic characteristics of the porcelain surge arrestor are evaluated considering the variation of its cable tension and stiffness by shaking table test. The test results show that the first natural frequencies are 5.3 Hz and 5.2 Hz in the horizontal x- and y-axis directions, respectively, and higher than 30 Hz in the vertical z-axis direction, respectively. The installation of cable on the surge arrestor reduces the horizontal natural frequencies due to the constraint effect of the cable but cable tension has no effect on the natural frequency. Also, the natural frequency is proportional to the stiffness of the surge arrestor. This test result will be used for the seismic design and seismic capacity assessment of domestic substations and contribute to the stability of the electric power supply under earthquake event.

• 한국해양공학회지
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• 제19권3호
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• pp.39-46
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• 2005

A series of forced oscillation tests on a model mooring chain was carried out to investigate dynamic tension characteristics. The model test was conducted at two different water depths to gather basic data for a 'truncated mooring test' and 'hybrid mooring test'. The truncated and hybrid mooring tests are important for overcoming the limitation of water depth that existed in previous model tests. The resultant tension RAO provides a good possibility of approximation of dynamic tension by equivalent weight adjustment for different water depths. Because the hybrid mooring test is an adequate combination of model test and simulation, an accurate simulation model for the mooring system is essential. The simulation results show good agreement with model test results.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.134-141
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• 2002

A series of forced oscillation test on model mooring chain was carried out to investigate dynamic tension characteristics. The model test was conducted at two different water depth to gather basic data for 'truncated mooring test' and 'hybrid mooring test'. The truncated and hybrid mooring test are highly recommended to overcome the limitation of water depth in model test recently. The resultant tension RAO gives good possibility of approximation of dynamic tension by equivalent weight adjustment for the ratio of water depth in different water depth. Because the hybrid mooring test is the adequate combination of model test and simulation, accurate simulation model on mooring system is essential. The simulation results show good agreement with model test results.

• 동력기계공학회지
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• 제16권1호
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• pp.65-71
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• 2012

A numerical procedure is described for predicting the dynamic structural responses of tension leg platforms(TLPs) in current and waves. The developed numerical approach is based on a combination of the three dimensional source distribution method and the dynamic structural analysis method, in which the superstructure of the TLPs is assumed to be flexible instead of rigid. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the dynamic structural analysis. The equations of motion of a whole structure are formulated using element-fixed coordinate systems which have the origin at the nodes of the each hull element and move parallel to a space-fixed coordinate system. The dynamic structural responses of a TLP were analyzed in the case of including the current or not including the one in waves and the effects of current on the TLP were investigated.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.76-81
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• 2002

The characteristics of the track are important concerning the mobility of tracked vehicles. It can be represented in terms of the track tension and maintaining the track tension adequately guarantees the stable and improved driving of the tracked vehicles. The track tension must be known in order to be controlled and it needs to be estimated in real-time because it is difficult to be measured. The tension around idler and sprocket can be controlled by the frizzy logic control system base on the estimated values. Dynamic Track Tensioning System(DTTS) which is estimating and controlling the track tension. In this paper, simulation tool is developed in order to apply the DTTS to real battle tanks. To construct the simulation tool, the Modeling the tracked vehicle, constructing estimation system, and designing controller should be achieved first and then all subsystem should be organized in one. The simulation tool make the RecurDyn model of tracked vehicle, which is plant model, and the control system exchange their data simultaneously. Simulation with many kinds of driving conditions and road conditions is carried out and the results are interpreted. The interpretation provides necessary information to apply the DTTS to real battle tanks.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권1호
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• pp.62-69
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• 2000

The strip tension as well as the line speed should be controlled tightly for the quality of products and productivity of the continuous strip processing line. In this paper, a new tension control algorithm with tension observer is proposed using observed tension as regulator feedback. The tension observer is based on the torque balance of a roller stand including the acceleration torque. Using this estimated tension, new tension controller can be constructed with faster dynamic response in case of line speed acceleration or deceleration. The proposed scheme needs no additional hardware because the inputs of observer, current and speed, are already being monitored by the motor drive system. Through the simulations and experiments with laboratory set up, performances fo conventional schemes and proposed one are compared. The results show the effectiveness of the proposed tension controller.