• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1389-1390
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• 2015

본 논문에서는 선도-추종자 로봇의 대형을 유동적으로 변형하며 장애물을 효과적으로 회피하는 방법을 제안한다. 로봇이 장애물을 회피함에 있어서 고정된 대형으로 이동하는데 어려운 문제가 발생한다. 본 논문에서는 이러한 문제점을 해결하기위해 장애물 회피시 선도로봇의 방향각과 위치, 선도로봇과 추종자 로봇의 거리를 이용하여 대형을 유동적으로 변형하여 장애물과의 충돌을 회피하는 방법을 사용하고 로봇의 경로계획을 위하여 포텐셜 필드 알고리즘을 사용하였다. 본 논문에서는 Matlab을 이용한 모의실험을 통하여 제안된 방법의 성능을 확인하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.187-187
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• 2022

최근 선박의 자율운항기술이 활발하게 연구되어 오면서, 경로추종 제어 및 충돌회피 등의 자율운항 기술 연구가 많이 진행되고 있으며 그에 따른 시뮬레이션과 실해역 시험 등도 활발하게 수행되고 있다. 이러한 자율운항기술 중 본 연구에서는 AUV(Autonomous Underwater Vehicle) 진회수 시 모함에 활용되며 쌍동선형을 갖는 쌍동형 무인수상선을 대상으로 경로추종 제어에 대한 실해역 시험을 수행한 내용을 소개한다. 대상선인 쌍동형 무인수상선은 배수량이 약 10ton, 최대속도 10knots를 기준으로 설계된 선형이며 Sail drive 타입의 쌍축 추진기를 탑재하고 있으며 Fig. 1에 나타내었다. 실해역 시험은 경기도 화성시에 위치한 제부마리나 전면 해역에서 여러 속도에 대해 Fig. 2의 경로(빨간색)를 활용하여 수행되었다. 해당 경로는 변침각이 45도까지 이루어져 있다. 경로추종 제어 알고리즘은 목표경유점을 향하기 위해 선수각을 제어하는 부분과 목표속도로 추진하기 위해 속도를 제어하는 부분으로 나뉘어져 있다. 선수각 제어 시 경로와 무인선과의 위치 오차를 줄이는 방향으로 선수각이 향할 수 있도록 알고리즘이 설계되었다. 속도 제어의 경우 RPM 별로 실제 속도를 계측하여 데이터화 한 후, 실제 속도가 명령 속도와 다를 경우 RPM을 가감하여 명령 속도로 추진하기 위해 제어할 수 있도록 하였다. Fig. 2에서 파란색 선은 설계한 알고리즘을 활용하여 경로추종 제어를 한 결과의 궤적을 보여준다.

• Journal of IKEEE
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• v.24 no.1
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• pp.275-283
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• 2020

A leader-follower robot system using low cost small mobile robots has been developed. Sine the developed mobile robot is made of widely used low cost parts, it can be built easily and fastly. Characteristics of the developed sensor array composed of seven low-cost infrared(IR) distance sensors has been investigated, and a positioning algorithm of the reader robot is proposed. Through a series of experiments, it has been verified that the proposed algorithm can detect the position of the reader robot well.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.4
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• pp.476-480
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• 2012

In this paper, artificial potential field(APF) is applied to formation control for the leader-following swarm robot. Furthermore, APF is constructed by applying the electrical field model. Moreover, to model the obstacle effectively, each obstacle has different form due to the electrical field equation. The proposed method is formed as two sub-objective: path planning for the leader-robot and following-robots following the leader-robot. Finally, simulation example is given to prove the validity of proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.804-807
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• 2003

Recently, standardization is essential strategic tool for a firm to preoccupy a market. Also WTO TBT(Technical Barriers to Trade) makes importance of standardization greater in telecommunication industry. Therefore countries, not to speak of firms, recognize standards essential strategy to preoccupy markets. In this paper, we will examine the standardization competition between a leader and a follower and their strategies through dynamic incomplete information game model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1811-1817
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• 2014

In this paper, a PID controller with interpolated gains by use of neural networks is proposed for the formation control problem that following robots track a leading robot with constant distances and angles when there are changes in the mass of the following robot. The whole control system is composed of a kinematic controller and a dynamic controller considering the robot dynamics. The dynamic controller is the PID controller with varying gains, and the proper gains are obtained for some representative masses of the follower robot by the genetic algorithm. Neural networks is trained using the genetic algorithm with the gain data obtained in the previous step. The trained neural network determines optimal PID gains for a random mass of following robot. Simulation studies show that for arbitrary masses of the tracking robot, the PID controller with interpolated gains by the trained neural network has better tracking performance than that of the PID controller with fixed gains.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.121-126
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• 2000

국내 원자력발전은 전체 전력공급의 40%이상을 차지하고 있으면서도 그 특성상 기저부하용으로만 사용되고 있다. 그러나 전기에너지의 효율적인 이용과 다양한 전력수요에 능동적으로 대처할 수 있도록 원전의 부하추종운전 능력이 더욱 중요하게 인식되고 있는 상황이다. G7과제의 하나인 차세대원자로(Korean Next Generation Reactor, KNGR)는 기본적인 요건으로 부하추종운전 능력을 갖도록 개발되고 있다. 여기에서는 기존에 개발된 부하추종운전 제어논리를 변경된 부하추종운전 기본요건에 맞도록 하고, 구동 제어군 특성의 극대화 및 온도불감대 출력분포 제어논리 등을 개선시킴으로써 주기초 및 주기중 뿐만아니라 90% 주기말에서도 ASI(Axial Shape Index)가 만족스럽게 제어됨을 확인하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.264-273
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• 2010

In this work, autonomous formation flight tests of multiple UAVs are experimentally studied. After a guidance and control system for a UAV is designed and tested, PID formation controller for follower UAV is tested using longitudinal and lateral distance feedback. It is shown that more stable and efficient formation guidance system is obtained by using position and attitude of the leader aircraft, which is exploited to calculate virtual waypoint for follower. In order to improve transient response during turn, part of roll command of the leader is added to the guidance command. Finally, autonomous formation flight test results of 3 UAVs are shown by using the best guidance algorithm suggested.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.827-832
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• 2013

In this study, curve responsiveness was assessed based on the lateral force and running safety was evaluated based on the wheel unloading ratio and derailment coefficient, which is the ratio of the wheel load and the lateral force. The evaluation of the curving performance and running safety of the new high-power electric locomotive showed that the derailment coefficient appeared higher when the wheel-set was set to the front of the train instead of being placed backward, and the maximum value of the derailment coefficient was recorded as 0.572 on the Gyeongbu line. Furthermore, the lateral force increased in curved sections, and it appeared to be proportional to the curve radius. Meanwhile, a maximum axis lateral force of 77.6 kN was recorded on the Taebaek line, and the wheel unloading ratio was 47.6% on the Yeongdong line. Finally, the running safety at the maximum speed as well as the through-curve performance of the curve radius satisfied the required standards.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.503-509
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• 2014

In this paper, a PID controller with adaptive neural network compensator is proposed to control the formations of mobile robot. The control system is composed of a kinematic controller based on the leader-following robot and dynamic controller for considering the dynamics of the mobile robot. The dynamic controller is constituted by a PID controller and the adaptive neural network compensator for improving the performance and compensating the change in dynamic characteristics. Simulation results show the performance of the PID controller and the neural network compensator for the circular trajectory and linear trajectory. And it is verified that by improving the performance of a PID controller via the adaptive neural network compensator, the following robot's tracking performance is improved.