• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.373-376
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• 2007

The construction industry is an inevitable part of modem development. Now-a-days, the construction industry experiencing several issues related with the maintenance of productivity, quality and labor. Hence there is an immediate requirement for the development of technologies enabling the automated construction equipment. The new technologies should also assure the sufficient safety and efficiency. In the present investigation, an attempts have been made for the development of object sensing algorithm and safety control system for intelligent excavating system. we have analyzed some elemental technologies for sensing objects and also proposed a technology for safety control system as well. The proposed technology will highly influence the safe working performance of construction industry in the positive sense.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.184-187
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• 1996

본 연구에서는 산업 현장에서 중장비 엔진마운트를 설계함에 있어서 벤치상태에서의 번거로움과 비현실성을 해결하고 실차상태의 하중 조건에 맞는 적절한 엔진마운트를 설계하기 위해 TDA(Time Domain Analysis) 기법을 도입하여 굴삭기 모델에 응용하여 이론치와 실험치를 비교 검토하고 승차감향상을 도모하였다.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.11-18
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• 2013

For a reliability assessment of machinery parts, accurate performance test, environmental test, life test, etc. are required on the sample. In the performance test conditions of various machinery parts, some problems happen such as needs to rise temperature rapidly with large flow of oil having very low thermal conductivity and to measure very high torque or tiny torque, etc. This study brings out the method to apply heat to rise temperature for large flow of oil without chemical change in a performance test of oil cooler. To measure large scale of torque in a performance test of planetary gearbox of excavator, the method of torque measurement is proposed by replacing the large torque meter priced very expensive. To measure very small torque on lubricated friction, a methode of force balance type test mechanism is introduced for tests of piston assembly.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.207-212
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• 2011

A hydraulic breaker is an attachment installed at the end of excavator arm and is used for breaking. As per the authors' knowledge, there have been no research results on reducing the weight of the hydraulic breaker even though this weight reduction is very important for improving the performance of the excavator. In this study, we minimize the weight of the housing of the hydraulic breaker under normal operating conditions, while the maximum stress of the housing is lower than the allowable stress. A meta-model, which is generated by using the CAE results for the sampling design points determined by an orthogonal array, is used to solve the minimization problem. The weight of the housing according to the optimal design is found to be lower than the original weight by 4.8% while satisfying the constraint on the maximum stress.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.375-380
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• 1993

We developed a part of stroke sensing cylinder and its measurement system for system for automatic excavator. In this paper, for development of stroke sensing sylinder, we consist of 2-axis control instrument system with magnetic sensor. A Performence of cylinder rod with magnetic scales is evaluated by its system. Furthmore, the position control for good performance of instrument system is achieved by a sliding mode control which is a new method diminishing the chattering in that control by setting 2-dead band along the swtching line. The unknown parameters for sliding mode control are estimated by the signal compression method.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.132.4-132
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• 2001

Field robot represented by excavator can be applied for various kinds of working in manufacturing, construction, agriculture etc. because of the flexibility of its multi-joint mechanism and the high power of hydraulic actuators. In general, the dynamics of field robot have strong coupling, various kinds of non-linearity, and time varying parameters according to working conditions. Therefore, it is very difficult to describe the system well, and design controller systematically based on its model. This paper established the mathematical model of field robot driven by electro-hydraulic servomechanism and constructed the adaptive control system robust to external load variations. The proposed control system for the field robot was evaluated by the computer simulation, and the performance results of trajectory tracking were compared with that of PID control system.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.71-77
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• 2008

Earthwork is very equipment-intensive task and researches related to automated excavation have been conducted. There is an issue to secure the safety for an automated excavating system. Therefore, this paper focuses on how to improve safety for semi- or fully-automated backhoe excavation. The primary objective of this research is to develop the core technology for automated object detection in excavation work. In order to satisfy the research objective, a diverse sensing technologies are investigated and analysed in terms of functions, durability, and reliability. The authors developed detecting algorithm for the objects using laser sensor and verified its performance by several tests. The results of this study would be the basis for developing the automated object detection system.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.10-21
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• 1996

In this study, as a strategy to improve shift characteristics, the authors developed a new style pressure modulator which can reduce shock torque during power shift by modulating the pattern of pressure increase in the cylinder for actuating the clutch. The remarkable merits of this new pressure modulator lie in its structural simplicity and durability, because the modulator is only composed of a poppet type valve and a few orifices. The usefulness of the new pressure modulator is confirmed by experiments and numerical analyses on a clutch control hydraulic system simplified for easy test. Also, the excellency of the transmission with the new pressure modulator is verified by experiments on a test bench for simulating the running power train of an excavator.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.2
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• pp.194-201
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• 2005

For engineers in the industry, this study considers a reliable and practical finite element modeling technique to estimate the behavior of closed thin-walled members with spot weldings. Dynamic and static experiments confirm that the technique - modeling the spot weldings with solid elements which have the adjusted rotational freedoms and fill the welding space - Yields satisfactory results. Numerical studies on the double hat-shaped members. adopting this modeling technique. show the effect of the spot welding Pitch and the spot welding location in the flange on the stiffness of the members Using the principal stiffness and newly proposed GSPI(global stiffness performance index), we also carefully examine how the spot welding curvature, and sectional shape, etc.. synthetically influence the stiffness of a real excavator pillar in the field.

• Korean Journal of Construction Engineering and Management
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• v.17 no.3
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• pp.116-124
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• 2016

Work efficiency of earth work which is one of the main works occurring in construction site mainly depends on the performance of individual operators of earth work equipment. Consequently, the skill of individual operators of earth work equipment can significantly affect overall construction schedules. Many invisible areas inevitably exist in construction site because of the nature of construction site where occlusions occur from structures being built, installed or moving equipment, moving workers, etc. The lack of visual information regarding tasks critically impedes the effective performance of operators of earth work equipment. AR (Augmented Reality) is a computer technology that superimposes virtual objects onto the real world scene. This characteristic of AR may address the lack of visual informations in earth work process, thus helping to improve the work efficiency of operators of earth work equipment. The purpose of this study is to present a task-visual information map that identifies visual informations required in tasks of earth work and which of the tasks are suitable for AR technology. This study focuses on visual informations in tasks of earth work with excavators. The map was created based on the investigations on the problems of each task of earth work with excavators and visual informations required to address the problems. Through the map, four visual informations were found to be suitable for AR technology to improve the work efficiency of excavator operators. Based on the findings of this study, AR systems for excavators can be developed more effectively.