• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.993-998
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• 1992

The paper treated the oscillation control of cargo rope and the position control of cart for a tower crane system by adopting the optimal regulator method. Since the tower crane has nonlinearity and it is very unstable when the cargo is mobiling, an insensitive control system with respect to oscillation of cargo rope and disturbance such as wind is required. In this paper, model equation of the tower crane is induced by using Lagrange equation and it is linearized at equilibrium point. The real time control of tower crane syste is implemented by 16bits microcomputer with A/D and D/A convetters to illustrate the application of the adopted optimal desgn method.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.11 no.2
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• pp.59-77
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• 2003

Air Traffic Control Tower is one of the most important units in Airport operation. It provides services related to safe and efficient traffic flows that control aircraft on the ground maneuvering area and terminal airspace. Also It is responsible for managing of ground operators. The major objective of this study is to evaluates relative efficiency of ATC towers in Domestic airports using data envelopment analysis so that it helps the ATC authority to improve the tower efficiency, to decide the level of benchmarking target and to establish the best alternative. The results of this study are the following; First, as a result of analysis for the potential improvement, it has analysed that the common problems of each ATC tower are to increase its number of flight and to reduce its number of runway followed by airside area, the number of air traffic controller and the number of stand. Second, it has shown that the each tower in RKPC(8), RKPT(5), RKPK(l) and RKSS(l) are used as the reference set. Especially, the tower in RKPC analyzed as a relatively efficient unit is the most main target for the towers in RKTU, RKTH, RKPS and RKTY to do bench marking and to set up the strategy for improving relative efficiency of the tower. Third, tower is actually not able to control the input and output data in this study except the number of controller, so that ATC authority is recommended to improve inefficiency of the towers through handling the number of controller.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.427-430
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• 2002

The present parer outlines the system identification and vibration control performance of air traffic control tower of Yangyang international airport with tuned mass damper(TMD). From the free vibration test, natural frequency, damping ratio and mode shape of tower are obtained and these values are compared with the values from numerical analysis. In the vibration control test to evaluate the vibration control performance, equivalent damping ratio increased by tuned mass damper are obtained in case the TMD is operated as passive mode. Damping ratio of tower evaluated from free vibration test is about $1.0{\%}$. It is very low value than damping ratio recommended in general code. Damping ratio of passive mode is about $5{\%}$. These equivalent damping ratio increased by TMD is enough to enhance the serviceability of tower structure under wind load.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.711-719
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• 2019

At present, wind power is the fastest growing technology in the world. The domestic market depends heavily on imports for wind tower lift. so it manage through the overseas maker. The lift manufacture, establishment and maintenance utility is increasing, localization development of one wind tower lift is necessary with domestic fundamental base technique. In this paper, we will study the components necessary for the development of onshore offshore wind tower elevators, which are currently dependent on total imports, in line with the high growth of the wind market and the enlargement of the wind power generators. First of all, endless winders and cabins, which are the core components of the offshore wind tower lift, were examined for the components that affect the structural safety. Structural analysis was performed on Sheave, which is responsible for most of the lift lifting loads, and Block Stop, a safety device that prevents the cabin from falling in an emergency. The structural suitability was evaluated by comparing with the safety factor. In addition, the on-board control panel combines the control panel of the elevator and the drive motor driving the endless winder for efficient control of the offshore wind tower lift. The addition of features improves ride comfort at departure.

• Journal of the Korea Institute of Construction Safety
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• v.2 no.2
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• pp.76-81
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• 2019

It becomes easy to acquire operating qualification of remote control tower crane and illegal retrofits is increased, remote control tower crane models are increasingly being used in smaller construction sites. However, as the problems caused by tower crane operators who have shortages of operating experience grow, safety accidents is increasing and worker is exposed to risk of accident. In this study, the cause of the accident was derived by analyzing the cause of the remote control tower crane accident. And then, the significance of accident causes was analyzed by AHP technique. The result of this study is that tower crane operators and construction workers do not comply with work rules.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.213-222
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• 1993

This paper is concerned with automation of tower cranes in view of the robust control of tower crane during take-off, load hoisting, load lowering and landing. The model equation of the tower crane is induced by using Lagrange's equation and it is linearized at equillibrium point. The control is realized by adopting the optimal regulator method. The effectiveness is proved through the experimental results for the oscillation control of cargo rope and the position controls of trolley and boom by the implementation of digital control using 16 bits microcomputer for the designed optimal control law.

• Structural Engineering and Mechanics
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• v.82 no.5
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• pp.571-585
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• 2022

As a vital component of power grids, long-span transmission tower-line systems are vulnerable to wind load excitation due to their high flexibility and low structural damping. Therefore, it is essential to reduce wind-induced responses of tower-line coupling systems to ensure their safe and reliable operation. To this end, a shape memory alloy-bidirectional tuned mass damper (SMA-BTMD) is proposed in this study to reduce wind-induced vibrations of long-span transmission tower-line systems. A 1220 m Songhua River long-span transmission system is selected as the primary structure and modeled using ANSYS software. The vibration suppression performance of an optimized SMA-BTMD attached to the transmission tower is evaluated and compared with the effects of a conventional bidirectional tuned mass damper. Furthermore, the impacts of frequency ratios and SMA composition on the vibration reduction performance of the SMA-BTMD are evaluated. The results show that the SMA-BTMD provides superior vibration control of the long-span transmission tower-line system. In addition, changes in frequency ratios and SMA composition have a substantial impact on the vibration suppression effects of the SMA-BTMD. This research can provide a reference for the practical engineering application of the SMA-BTMD developed in this study.

• Smart Structures and Systems
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• v.24 no.1
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• pp.1-14
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• 2019

Transmission tower-line system is one of most critical lifeline systems to cities. However, it is found that the transmission tower-line system is prone to be damaged by earthquakes in past decades. To mitigate seismic demands, this study introduces a tuned-mass damper (TMD) using superelastic shape memory alloy (SMA) spring for the system. In addition, considering the dynamic characteristics of both tower-line system and SMA are affected by temperature change. Particular attention is paid on the effect of temperature variation on seismic behavior. In doing so, the SMA-TMD is installed into the system, and its properties are optimized through parametric analyses. The considered temperature range is from -40 to $40^{\circ}C$. The seismic control effect of using SMA-TMD is investigated under the considered temperatures. Interested seismic performance indices include peak displacement and peak acceleration at the tower top and the height-wise deformation. Parametric analyses on seismic intensity and frequency ratio were carried out as well. This study indicates that the nonlinear behavior of SMA-TMD is critical to the control effect, and proper tuning before application is advisable. Seismic demand mitigation is always achieved in this wide temperature range, and the control effect is increased at high temperatures.

• Wind and Structures
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• v.9 no.5
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• pp.345-356
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• 2006

It is well known that cylinder steel stacks are heavily impacted by vortex-induced vibration. However, the wind-induced vibration behaviors of tower-supported steel stacks are not clarified due to a lack of observation. We studied a stack's response to strong winds over a long period of time by observing the extreme wind-induced vibration of a 200 m-high tower-supported steel stack. This experiment aimed to identify the wind-induced vibration properties of a tower-supported steel stack and assess the validity of the vibration control method used in the experiment. Results revealed a trend in wind-induced vibration behavior. In turn, an effective measure for controlling such vibration was defined by means of increasing the structural damping ratio due to the effects of the tuned mass damper to dramatically decrease the vortex-induced vibration of the stack.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.36-41
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• 2008

Cooling tower is an important equipment of the cooling systems for large buildings like factory and department store. Water used for cooling in cooling tower is reused continuously. If the water is polluted, corrosion and scale can happen at equipments and pipes. In order to prevent this problem, it is necessary to control the water quality using chemicals. To control the water quality, an automatic control system is designed, fabricated, and experimented. The control system is based on an imbedded microcontroller. Relays are used for power driving, an LCD and LED for display, and RS485 for remote data acquisition. Monitoring program is also developed for easy man-machine interface and extraction of data stored in the imbedded processor and EEPROM. The control system calculates amounts of chemicals necessary using sensor data and injects the chemicals into the cooling tower on proper time. The developed water quality control system is expected to reduce cost of maintenance and extend the lifetime of the cooling systems with low cost.