• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.278-278
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• 2004

실버용 로봇은 종래의 일반적인 로봇하고는 달리 매우 다양하고 복잡한 기능이 요구된다. 실버용 로봇이 주어진 작업을 성공적으로 수행하기 위해서는 인간의 두뇌작용에 해당하는 지능제어시스템과 이를 바탕으로 한 자율기능, 높은 수준의 인간과 로봇과의 통신을 위한 적절한 인터페이스, 고기능 센서를 이용한 감각기능, 로봇의 활동범위를 넓혀주는 이동기능, 조작을 위한 매니퓰레이션기능, 그리고 임무수행을 위한 처리기능 등이 필요하다. 이러한 다양하고 복잡한 작업을 수행하기 위해서는 지능적인 제어가 요구된다.(중략)

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.6
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• pp.88-96
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• 2011

Underwater acoustic communication is applicable in various areas, such as ocean data collection, undersea exploration and development, tactical surveillance, etc. Thus, robot control system construction used for underwater-robot like AUV or ROV is essential in these areas. In this paper, we propose the Message Merging MAC($M^2$-MAC) protocol, which is suitable for real time robot control system, considering energy efficiency in important parts of underwater acoustic sensor network constitution. In this proposed MAC protocol, gateway node receives the data from robot nodes according to the time slots that were allotted previously. And messages delivered from base-station are generated to one MAC frame by buffering process. Finally, generated MAC frames are broadcasted to all robot nodes in the cluster. Our suggested MAC protocol can also be hybrid MAC protocol, which is successful blend of contention based and contention-free based protocol through relevant procedure with Maintenance&Sleep (M&S) period, when new nodes join and leave as an orphan. We propose mathematical analysis model concerned about End-to-End delay and energy consumption, which is important factor in constructing real-time robot control system. We also verify the excellence of performance according to comparison of existing MAC protocols with our scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1605-1614
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• 2009

The technique of simultaneous localization and mapping is the most important research topic in mobile robotics. In the process of building a map in its available memory, the robot memorizes environmental information on the plane of grid or topology. Several approaches about this technique have been presented so far, but most of them use mapping technique as either grid-based map or topology-based map. In this paper we propose a frame of solving the SLAM problem of linking map covering, map building, localizing, path finding and obstacle avoiding in an automatic way. Some algorithms integrating grid and topology map are considered and this make the SLAM performance faster and more stable. The proposed scheme uses an occupancy grid map in representing the environment and then formulate topological information in path finding by A${\ast}$ algorithm. The mapping process is shown and the shortest path is decided on grid based map. Then topological information such as direction, distance is calculated on simulator program then transmitted to robot hardware devices. The localization process and the dynamic obstacle avoidance can be accomplished by topological information on grid map. While mapping and moving, pose of the robot is adjusted for correct localization by implementing additional pixel based image layer and tracking some features. A laser range finer and electronic compass systems are implemented on the mobile robot and DC geared motor wheels are individually controlled by the adaptive PD control method. Simulations and experimental results show its performance and efficiency of the proposed scheme are increased.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2493-2503
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• 2018

Passive dynamic walking exhibits humanoid and energy efficient gaits. However, optimal design of passive walker at multi-variable level is not well studied yet. This paper presents a Chaotic Particle Swarm Optimization (CPSO) algorithm and applies it to the optimal design of flexible passive walker. Hip torsional stiffness and damping were incorporated into flexible biped walker, to imitate passive elastic mechanisms utilized in human locomotion. Hybrid dynamics were developed to model passive walking, and period-one gait was gained. The parameters global searching scopes were gained after investigating the influences of structural parameters on passive gait. CPSO were utilized to optimize the flexible passive walker. To improve the performance of PSO, multi-scroll Jerk chaotic system was used to generate pseudorandom sequences, and chaotic disturbance would be triggered if the swarm is trapped into local optimum. The effectiveness of CPSO is verified by comparisons with standard PSO and two typical chaotic PSO methods. Numerical simulations show that better fitness value of optimal design could be gained by CPSO presented. The proposed CPSO would be useful to design biped robot prototype.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.332-335
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• 2006

전극 전해질 복합체가 하나로 구성된 단위전지는 전기출력이 낮아 원하는 전기출력을 얻기 위하여 단위전지를 여러 장 직렬로 쌓아 스택을 구성하여야 한다. 본 연구에서는 400W급 직접메탄을 연료전지 스택을 제조하여, 운전 조건의 최적화를 위한 실험을 수행하였고, 한국형 휴머노이드 로봇인 Hubo에 적용하여 그 동특성을 평가하였다. 0.8M 메탄을 용액은 260 ml/min의 유량을, 공기는 42LPM을 스택에 주입하여 400W의 성능을 나타내었다. 연료전지 스택의 온도와 전압의 편차는 작았으며 정상 운전시스템의 온도는 약 $70^{\circ}C$를 유지하였다. 로봇의 필요 전력이 높을 경우, 배터리와 연료전지가 동시에 부하 변동에 대응하였다 방전된 배터리는 로봇의 필요 전력이 낮아질 경우, 충전되어 이후의 방전 상황에 대비하였다. 연료전지 시스템 적용 결과 로봇의 성공적인 운전을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1838-1854
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• 2023

This paper presents a hybrid algorithm to solve the multi-objective path planning (MOPP) problem for mobile robots in a static nuclear accident environment. The proposed algorithm mimics a real nuclear accident site by modeling the environment with a two-layer cost grid map based on geometric modeling and Monte Carlo calculations. The proposed algorithm consists of two steps. The first step optimizes a path by the hybridization of improved ant colony optimization algorithm-modified A^* (IACO-A^*) that minimizes path length, cumulative radiation dose and energy consumption. The second module is the high radiation dose rate avoidance strategy integrated with the IACO-A^* algorithm, which will work when the mobile robots sense the lethal radiation dose rate, avoiding radioactive sources with high dose levels. Simulations have been performed under environments of different complexity to evaluate the efficiency of the proposed algorithm, and the results show that IACO-A^* has better path quality than ACO and IACO. In addition, a study comparing the proposed IACO-A^* algorithm and recent path planning (PP) methods in three scenarios has been performed. The simulation results show that the proposed IACO-A^* IACO-A^* algorithm is obviously superior in terms of stability and minimization the total cost of MOPP.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1786-1790
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• 2004

The main objective of this paper is to analyze the performance of various force control algorithms in improving and adjusting the compliance of industrial robots in contact with their environment. Some of fundamental force control algorithms such as sensorless control, impedance control and hybrid position/force control are theoretically analyzed and simulated for various situations of an environment, and then a series of experiments using them were performed. In this paper, a control scheme to use position control in implementing the impedance control was investigated in order to nullify the effect of joint friction. The new reference trajectory is generated using contact force feedback and original desired trajectory. And an inner position control loop is designed to provide accurate position tracking for the new reference trajectory and good disturbance rejection. Experiments to insert a peg in a hole (so-called the peg-in-a-hole task) were performed with HILS (hardware-in-theloop simulation) system based on the results of the analyses and simulations on the characteristics of each control algorithm. The experiments showed that various force control methods improved the performance of robots in close contact with the environment by adjusting their compliance with respect to an arbitrary set of coordinates.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.9
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• pp.796-802
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• 2000

A master-slave system for teleoperation is usually used to control the robor's motion on remote place such as abyss, outer space etc.. When the slave robot is a humanoid one, it can make a better performance if the configuration of the master arm is similar to that of the slave arm and of the human. The master arm proposed in this paper has a type to be put on the human arm, that is, the exoskeleton type, and has a combination of serial joint and parallel mechanism imitating the human's arm structure of muscles and bones, so called hybrid mechanism so that it can follow arm's movement effectively. But it is easy to solve the forward kinematis of the parallel structure because relating equations are implicit functions. In order to solve that, the virtual joint angle corresponding to human arm's joint is introduced and a sequential computation step is employed in calculating virtual joint angles and the posture of the end effector. Also validity is checked up through computational simulation.

• Journal of Gastric Cancer
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• v.21 no.3
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• pp.308-318
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• 2021

Purpose: The benefits of robotic gastrectomy remain controversial. We designed this study to elucidate the advantages of a hybrid robot and laparoscopic gastrectomy over conventional laparoscopic surgery. Materials and Methods: A total of 176 patients who underwent gastrectomy for gastric cancer were included in this study. We compared 88 patients treated with hybrid robotic and laparoscopic gastrectomy (HRLG) and 88 patients who underwent conventional laparoscopic gastrectomy (CLG). In HRLG, suprapancreatic lymph node (LN) dissection was performed in a robotic setting. Clinicopathological characteristics, operative details, and short-term outcomes were analyzed for the patients. Results: The number of LNs retrieved from the suprapancreatic area was significantly greater in the HRLG group (11.27±5.46 vs. 9.17±5.19, P=0.010). C-reactive protein levels were greater in the CLG group on both postoperative day (POD) 1 (5.11±2.64 vs. 4.29±2.38, P=0.030) and POD 5 (9.86±6.51 vs. 7.75±5.17, P=0.019). In addition, the neutrophil-to-lymphocyte ratio was significantly greater in the CLG group on both POD 1 (7.44±4.72 vs. 6.16±2.91, P=0.031) and POD 5 (4.87±3.75 vs. 3.81±1.87, P=0.020). Pulmonary complications occurred only in the CLG group (4/88 [4.5%] vs. 0/88 [0%], P=0.043). Conclusions: HRLG is superior to CLG in terms of suprapancreatic LN dissection and postoperative inflammatory response.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.5
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• pp.311-318
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• 2017

A reduced order observer is developed for depth control of a hybrid underwater glider which combines the good aspects of a conventional autonomous underwater vehicle and a underwater glider. State variables include the center of gravity of the robot and the weight of the buoyancy bag, which can not be directly measured. By using the mathematical model and available information such as directional velocities, accelerations, and attitudes, we developed a Luenberger's reduced order observer to estimate the center of gravity and the buoyancy weight. By simulations using Matlab/Simulink, the efficiency of the proposed observer is shown, where a LQR controller using full state variables is adopted as a depth controller.