• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.76-83
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• 2010

There have been many studies regarding development of autonomous excavation system which is helpful in construction sites where repetitive jobs are necessary. Unfortunately, bucket trajectory planning was excluded from the previous studies. Since, the best use of excavator is to dig efficiently; purpose of this research was set to determine an optimized bucket trajectory in order to get best digging performance. Among infinite ways of digging any given path, criterion for either optimal or efficient bucket moves is required to be established. One method is to adopt work know-how from experienced excavator operator; However the work pattern varies from every worker to worker and it is hard to be analyzed. Thus, other than the work pattern taken from experienced operator, we developed an efficiency model to solve this problem. This paper presents a method to derive a bucket trajectory from optimization theory with empirical CLUB soil model. Path is greatly influenced by physical constraints such as geometry, excavator dimension and excavator workspace. By minimizing a energy function under these constraints, an optimal bucket trajectory could be obtained.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.495-496
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• 2008

• International conference on construction engineering and project management
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• 2013.01a
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• pp.209-212
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• 2013

Global warming and climate change is now an important issue in every industry. Construction is not an exception. Greenhouse Gases (GHG) are emitted by construction activities such as fuel usage in construction equipment and so on. In light of this, Intelligent Excavating System (IES), which is a robotic excavator with site modeling capability, is developed by a research consortium formed in Korea to improve productivity, quality, and safety of the traditional earthwork. This paper presents that energy saving effect of IES in comparison to traditional method. Through this review, we propose a research strategy to achieve carbon reduction goals in construction industry.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.65.6-65
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• 2002

In teleoperation robotic system such as hydraulically actuated robotic excavator for dangerous area, the maneuverability and convenience is the most important part. Particularly the force information is important in dealing with digging and leveling operation in the tole-operated excavator. Excavators are also subject to a wide variation of soil-tool interaction forces. This paper proposes a new force reflecting joystick using pneumatic motor and a new algorithm for selecting force-reflecting gain in a velocity-force type bi lateral teleoperation system. The master system is electrical joystick with the same structure of that of real excavator. Particularly Pneumatic motor is used newly in...

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.552-557
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• 2004

This paper presents a disturbance observer based on an $H_{\infty}$ controller synthesis for the trajectory control of a hydraulic excavator. Compared to conventional robot manipulators driven by electrical motors, the hydraulic excavator has more nonlinear and coupled dynamics. In particular, the interactions between an excavation tool and the materials being excavated are unstructured and complex. In addition, its operating modes depend on working conditions, which make it difficult to not only derive the exact mathematical model but also design a controller systematically. In this study, the approximated linear model obtained through off-line system identification is used as nominal plant model for a disturbance observer. A disturbance observer based tracking controller which considers the effect of disturbance and model uncertainty is synthesized in $H_{\infty}$ frameworks. Simulation results are used to demonstrate the applicability of the proposed control scheme.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4D
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• pp.433-442
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• 2010

Recent decrease in the availability of experienced skilled labor and a corresponding lack of new entrants has required the need for automating many of the construction equipment used in the construction industry. In particular, excavators are widely used throughout earthwork operations and automating its tasks enables work to be performed with higher productivity and safety. This paper introduces an optimal path generation method which is one of the core technologies required to make "Intelligent" excavators a reality. The method divides a given earthwork area into unit cells, identifies networks created by linking these cells, and identifies the optimal path an excavator should follow to minimize its total transportation costs. In addition, the method also accounts for drainage direction and path continuity to ensure that the generated path considers site specific conditions.

• 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.

• Journal of Drive and Control
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• v.21 no.1
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• pp.31-37
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• 2024

In this study, to prevent accidents in underground facilities during excavation, we developed a Lv.3 automated control system that can be configured as an electronic control system without changing the existing hydraulic system in a general excavator and utilized digital map information of underground facilities. We aimed to develop a strategy to prevent accidents caused by operator error. To implement this, a real-time excavator bucket end position recognition and control system was developed through angle measurement of the boom, arm, and bucket using an electronic joystick, RTK-GPS, and angle sensors. In addition, excavators are large, machine-based equipment, and it is difficult to control overshoot due to inertia with feedback control using position recognition information of the bucket tip. Therefore, feed-forward control is used to calculate the moving speed of the bucket tip in real-time to determine the target position. We developed a technology that can converge and verified the performance of the developed system through actual vehicle installation and field tests.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.29-36
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• 2006

The hydraulic excavators are mainly applied for excavating, public works, quarrying, etc. In some of the construction site, however, they are used for crane works of relatively light materials, although the crane works by the hydraulic excavators are forbidden by law due to the safety reasons. The major construction equipment companies in forward countries have been developing the new systems, e.g. crane works by the hydraulic excavators, and they are working in the construction site. Therefore, the new system of crane works by the hydraulic excavators should be developed for the domestic construction site in order to prevent the accident. In this paper, the fundamental study and experiment are accomplished for the crane system application on the hydraulic excavators.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.609-612
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• 2008

Since most of the industries have adopted automation system, the industrial disaster has been declined sharply. Also automation system has offered many benefits such as productivity and assured quality. However, the construction industry is still relying on man power and because of this there are many victims occurring due to the industrial disaster. Construction industry has to overcome uncertainty of incidents and changing natural surroundings to actualize automation. Therefore, the efficient working plan and intelligent decision making process are needed to run more developed techniques and automations. Specially to decline the rate of industrial accidents occurred in basic construction in earth work, the automation via excavator is necessary and also the development of planning process system is too. This research is to establish Task Planning System to prevent disaster which is used for planning automated earth work.