• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1788-1791
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• 1997

In this paper constant-level luffing and time optimal control of a JIB crane is investigated. The crane is assumed to have only the derricking motion. the analysis of plance kinematics provides the relationship between the boom angle and the main hosit motor angle for constant-level luffing. The dynamic equations for the crane are very nonlimear, and therefore they are linearized for the application of the linear control theory. The time optimal control in the perspective of no-sway at the end of boom stroke is investigated.

• 대한금속재료학회지
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• 제48권6호
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• pp.489-497
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• 2010

The remaining life estimation of the level luffing crane component, which has operated for about 20 years is examined carefully, especially on the crane structures. To analyse the crane sructures, the basic load and load combination needed to be considered. We modeled various parts of the level luffing crane to analyse fatigue. Fatigue analysis results showed that the level luffing crane is in the fatigue life so that the crane is in the safe state in fatigue cumulative damage. Analysis results show that the remaining life of a jib upper beam would be about 10 years therefore, the level luffing crane should be stable for fatigue for that period.

• 한국강구조학회 논문집
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• 제12권6호
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• pp.715-725
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• 2000

본 논문은 링크구성 설계를 통하여 결정된 하나의 이중링크 형식 수평인입 집 크레인에 대하여 작업위치에 따라 각 링크의 변위, 속도, 가속도 해석을 하고, 인입 가감속에 의한 관성력, 바람에 의한 풍하중, 크레인 자중 및 정격 권상하중 등이 크레인에 작용할 때 인입장치에 요구되는 정적 힘을 계산하였다. 모든 해석과정은 전산 프로그램으로 작성되었고, 프로그램의 신뢰성은 관련 범용 소프트웨어들의 해석 결과와 비교하여 검증하였다. 따라서, 본 논문에서 개발한 전산 프로그램은 이중링크 형식 수평인입 집 크레인의 설계 실무에 있어서 이동하중에 대한 인입궤적의 진폭 및 작업위치에 따라 인입장치에 요구되는 힘의 해석을 신속, 정확하게 처리할 수 있어 설계의 생산성 및 신뢰성 제고뿐만 아니라 기본설계 기술력의 확보 측면에서 그 의의가 있다.

• 동력기계공학회지
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• 제15권1호
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• pp.57-63
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• 2011

It is very important to determine link composition of a crane in the basic design of the crane. There are many parameters in the design for the link composition of a double link type level luffing jib crane. We analyze the variation of link composition according to the variation of these parameters which are the angle of fixed link, the angle between the fixed link and backstay when the position of the crane is the maximum working radius, the ratio of fly jib length between two moving hinges to the total length of fly jib, the length of backstay, and the slewing radius. In this paper, we describe the application of the previous analysis program of the link composition design for a double link type level luffing jib crane.

• 한국정밀공학회지
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• 제30권9호
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• pp.983-990
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• 2013

Evaluation of the structural analysis for a 70/15 ton${\times}$105 m LLC (Level Luffing Crane) was conducted with an FEM Tool. Due to a discordance of the modeling and element type, the LLC was progressively analyzed after dividing it into the boom, main structure and rocker. All loads such as slewing, traveling and wind load, etc., that are indicated in the reference standards, were inputted as various severe conditions of the LLC. The deformation, equivalent stress(Von Mises stress), buckling characteristics were evaluated for the LLC structures. The stress concentrated areas over the allowable stress were identified, and reinforcement work was performed with a stiffener.

• 동력기계공학회지
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• 제13권1호
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• pp.19-25
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• 2009

This paper is a study on the link composition design of a double link type level luffing jib crane using path generation synthesis passing through three precision points according to parameters, the length of backstay, the ratio of fly jib length between two moving hinges to the total length of fly jib, the location of a intermediate passing point etc. when the maximum and minimum working radius of the crane are given. The performance of the crane depends on the deviation of the luffing trajectory at fly jib tip. The luffing trajectories according to the above parameters are analyzed and shown in graphs by the developed computer program. In a real-life design, some trials are needed to arrive at a proper link composition design. Therefore, it is expected that the present computer program can rapidly and exactly deal with a link composition design proper to the design criteria of the crane.

• 한국해양공학회지
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• 제19권1호
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• pp.87-94
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• 2005

This paper investigates the constant-level luffing and time optimal control of jib cranes. The constant-level luffing, which is the sustainment of the load at a constant height during luffing, is achieved by analyzing the kinematic relationship between the angular displacement of a boom and that of the main hoist motor of a jib crane. Under the assumption that the main body of the crane does not rotate, the equations of motion of the boom are derived using Newton's Second Law. The dynamic equations for the crane system are highly nonlinear; therefore, they are linearized under the small angular motion of the load to apply linear control theory. This paper investigates the time optimal control from the perspective of no-sway at a target point. A stepped velocity pattern is used to design the moving path of the jib crane. Simulation results demonstrate the effectiveness of the time optimal control, in terms of anti-sway motion of the load, while luffing the crane.

• 대한기계학회논문집A
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• 제32권6호
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• pp.526-532
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• 2008

Structure evaluation for 70/15 $T{\times}105\;m$ LLC(Level Luffing Crane)'s boom was conducted by Finite Element Method. Boom modeled with beam element was fixed by luff rope and boom mount and was received loads from self weight, luff hoisting, traveling motion, slewing motion, and wind force, etc. These applied loads were calculated using various factors presented in the reference standards and were inputted in the analysis model after considering about the adverse conditions of LLC. In the research, deformation, stresses, buckling of boom were evaluated by ANSYS. Structural safety of boom was confirmed in the results of numerical analysis.

• 한국안전학회지
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• 제16권4호
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• pp.65-73
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• 2001

This paper is a study on the fatigue analysis using BS5400 Part10(1980), code of practice for fatigue for a double link type level luffing jib crane which has been operated since the crane was built in 1985 at a domestic pier. South Korea. In addition, on the basis of the design lift due to fatigue analysis and the number of cracks detected from the nondestructive test the structural reliability and the residual life of the crane is predicted by evaluating the expected development of detectable fatigue oracle during the next five to ten years using Paris's Law for predicting fatigue crack growth and Gaussian probability density function to be reasonable for stress ranges below the mean values determined by laboratory tests. The statistical data used for the analysis of the structural reliability and life expectancy is given in the above referred code.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.250-256
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• 2009

This paper presents a robotic tower-crane system using encoder and gyroscope sensors as path tracking devices. Tower crane work is often associated with falling accidents and industrial disasters. Such problems often incur a loss of time and money for the contractor. For this reason, many studies have been done on an automatic tower crane. As a part of 5-year 23-million-dollar research project in Korea, we are developing a robotic tower crane which aims to improve the safety level and productivity. We selected a luffing tower crane, which is commonly used in urban construction projects today, as a platform for the robotic tower crane system. This system comprises two modules: the automated path planning module and the path tracking module. The automated path planning system uses the 3D Cartesian coordinates. When the robotic tower crane lifts construction material, the algorithm creates a line, which represents a lifting path, in virtual space. This algorithm seeks and generates the best route to lift construction material while avoiding known obstacles from real construction site. The path tracking system detects the location of a lifted material in terms of the 3D coordinate values using various types of sensors including adopts encoder and gyroscope sensors. We are testing various sensors as a candidate for the path tracking device. This specific study focuses on how to employ encoder and gyroscope sensors in the robotic crane These sensors measure a movement and rotary motion of the robotic tower crane. Finally, the movement of the robotic tower crane is displayed in a virtual space that synthesizes the data from two modules: the automatically planned path and the tracked paths. We are currently field-testing the feasibility of the proposed system using an actual tower crane. In the next step, the robotic tower crane will be applied to actual construction sites with a following analysis of the crane's productivity in order to ascertain its economic efficiency.