• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.722-728
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• 1998

In this paper real-time estimation methods for identifying the tire-road friction coefficient are presented. Taking advantage of the Magic Formula Tire Model, the similarity technique and the specific model for the vehicle dynamics, a reduced order observer/filtered-regressor-based method is proposed. The Proposed method is evaluated on simulations of a full-vehicle model with an eight state nonlinear vehicle/transmission model and nonlinear suspension model. It has been shown through simulations that it is possible to estimate the tire-road friction from measurements of engine rpm, transmission output speed and wheel speeds using the proposed identification method. The proposed method can be used as a useful option as a part of vehicle collision warning/avoidance systems and will be useful in the implementation of a warning algorithm since the tire-road friction can be estimated only using RPM sensors.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1063-1072
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• 1996

Fruit harvesting robots should have more diversity and flexibility in the working conditions and environments than industrial robots. This paper presents an efficient optimization algorithm for redundant manipulators to avoid obstacles using dynamic performance criteria, while the optimization schemes of the previous studies used the performance criteria using kinematic approach. Feasibility and effectiveness of this algorithm were tested through simulations on a 3-degrees-of-freedom manipulator made for this study. Only the position of the end-effector was controlled , which requires only three degrees of freedom. Remaining joints, except for the wrist roll joint, which does not contribute to the end-effector linear velocity, provide two degrees of redundancy. The algorithm was effective to avoid obstacles in the workspace even through the collision occurred in extended workspace, and it was found be to a useful design tool which gives more flexibility to design conditions nd to find the mechanical constraints for fruit harvesting robots.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.245-246
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• 2006

For developing 5-axis laser cutting systems, many problems such as rotating of laser head or table, 5-axis tool path generation and collision avoidance between laser head and product should be solved. In this paper, a five-axis laser cutting machine with table swivel and rotary type configuration is developed. The five axes (X,Y,Z,A,B) are controlled and interfaced to PC via MMC board. Two kinds of CAM S/W such as commercial 5-axis CAM S/W(Euclid) and UG-API are engaged to generate NC code for the developed 5-axis laser cutting machine.

• Journal of the Korea Society for Simulation
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• v.8 no.3
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• pp.67-76
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• 1999

The study of the optimization of operating policy of AGV system, which is used in many factory automation environments has been proceeded by many researchers. The major operating policy of AGV system consists of routing and scheduling policy. AGV routing is composed with collision avoidance and minimal cost path find algorithm. To allocate jobs to the AGV system, AGV scheduling has to include AGV selection rules, parking rules, and recharging rules. Also in these rules, the key time parameters such as processing time of the device, loading/unloading time and charging time should be considered. In this research, we compare and analyze several operating policies of multiple loop-multiple AGV system by making a computer model and simulating it to present an appropriate operating policy.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.5
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• pp.281-286
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• 2011

FMCW Radar sensor is commonly used for an automobile collision avoidance system for rider's safe. Systems using FMCW radar, however, would be one of expensive solutions for just simple rear obstacle detection purpose due to its high cost. In this letter, a short range rear obstacle detector using novel 24GHz AM radar sensor is presented. It can be implemented at significantly lower cost than FMCW radar for practical commercialization. The proposed AM radar sensor module is fabricated in a single aluminum housing to reduce the overall size while using single power supply voltage of 12V with 1200mA current for automotive applications. The measured detection range is up to 210cm with 10cm of distance resolution, which is suitable for a parking assistance system for automobiles.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.170-177
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• 1993

In robotic arc welding, the roll (rotation) of the torch about its direction vector does not have any effect on the welding operation. Thus we could use this redundant degree of greedom for the motion control of the robot manipulator. This paper presents an algorithm for the pseudo- inverse kinematic motion control of the 6-axis robot, which utilizes the above mentioned redunancy. The prototype welding operation and the tool path are also graphically simulated. Since the proposed algorithm requires only the position and normal vector of the weldine as an input data, it is useful for the CAD-based off-line programming of the arc welding robot. In addition, it also has the advantages of the redundant manipulator motion control, like singularity avoidance and collision free motion planning, when compared with the other motion control method based on the direct inverse kinematics.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.37-45
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• 1999

In the decision of a collision avoidance action for navigators and intelligent ships, it is necessary to evaluate the degree of surrounding risks and to control them effectively. In this paper, we propose the new methodology for navigational risk evaluation and control at sea. In the methodology, navigation risk is evaluated in two dimensions using Even Risk Contour on the basis of the concept of contour line. In addition, the movement information of dangerous targets is assessed continuously and precisely with wide band data. The presented technique is useful for the safety navigation at the heavy traffic sea and will be applied for the ultra automatic ship.

• Journal of the Korean Society of Marine Environment & Safety
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• v.8 no.2
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• pp.9-15
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• 2002

Ship operators use anchor dredging for the collision avoidance or safety of ship handling in a harbour or narrow channel. This paper clarifies the technique of the anchor dredging known as a common sense for. the seafarers A mathematical model at low speed range is established for the estimation of ship motion under the assumed environment, simulate the advance speed , and turning ability under the anchor dredging or not. The results shows good agreement with the conventional seamanship and their experiences as follows. Ahead speed used the anchor dredging is slower(speed reduction ratio:40%) than the normal ahead speed and the stopping distance is shorter (distance reduction ratio:40%)than the normal ahead distance without the anchor dredging.. Turning speed used anchor dredging is slower(speed reduction ratio:72%)than the normal ahead speed and the tactical diameter is shorter(distance reduction ratio:24%)than the diameter by the normal turning without the anchor dredging.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1833-1834
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• 2008

본 논문에서는 다수의 AGV를 운용하는 물류자동화창고에서 최단경로가 배정된 AGV의 주행도중 발생하는 충돌 및 교착 상태를 예측하고 이를 회피하는 알고리즘을 개발하고자 한다. 충돌 및 교착 상태는 최단 경로와 경로 점유시간을 비교함으로써 예측하고 이를 경로 선입에 따른 우선권 및 지연시간에 따른 우선권에 따라 회피할 AGV를 선정함으로써 충돌 회피에 따른 AGV의 총 운행시간을 최소화한다.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.297-303
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• 2009

Automatic Identification System (AIS) is a VHF radio broadcasting system where transmits packets of data via VHF data link. It enables vessels and coastal-based station that equipped with AIS equipment to send and receive useful information. This information can be help in situational awareness and provide a means to assist in collision avoidance. In addition, AIS can be use as Aid-To-Navigation, by providing the location and additional information on buoys and lights. Besides, it can also contain details information in meteorological status of a particular ship location. This paper presents the standalone AIS system that able to receive and report own ship location, meteorological data collection and broadcast safety related information if necessary. With the unique ship's MMSI number, all the information of that particular ship can be monitor by using AIS program written in C++ programming language.