• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3105-3107
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• 1999

In this paper, we propose a new approach to autonomous wall-following of wheeled mobile robots using hybrid control system. The hybrid control approach IS introduced to the motion control of nonholonomic mobile robots in the Indoor navigation problems. In hybrid control architecture, the discrete states are defined by the user-defined constraints, and the reference motion commands are specified In the abstracted motions. The hybrid control system applied to motion planning and autonomous navigation with obstacle avoidance In indoor navigation problem. Simulation results show that it is an effective method for the autonomous navigation in indoor environments.

• 제어로봇시스템학회논문지
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• 제16권9호
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• pp.898-904
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• 2010

Unmanned autonomous forklifts have a great potential to enhance the productivity of material handling in various applications because these forklifts can pick up and deliver loads without an operator and any fixed guide. There are, however, many technical difficulties in developing such forklifts including localization, map building, sensor fusion, control and so on. Implementation, which is often neglected, is one of practical issues in developing such an autonomous device. This is because the system requires numerous sensors, actuators, and controllers that need to be connected with each other, and the number of connections grows very rapidly as the number of devices grows. Another requirement on the integration is that the system should allow changes in the system design so that modification and addition of system components can be accommodated without too much effort. This paper presents a network-based distributed approach where system components are connected to a shared CAN network, and control functions are divided into small tasks that are distributed over a number of microcontrollers with a limited computing capacity. This approach is successfully applied to develop an unmanned forklift.

• Human Ecology Research
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• 제61권3호
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• pp.429-443
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• 2023

The purpose of this study was to investigate whether internal control, autonomous motivation of middle school students, and perceived parental pressure on academic performance affect academic procrastination, while verifying the moderating roles of autonomous motivation and parental pressure on academic performance. The participants were a total of 371 middle school students. Academic procrastination, internal control, autonomous motivation, and parental pressure on academic performance were measured using the Procrastination Inventory (Aitken, 1982) revised by Jeon and Park (2014), the Internal-External Control Scale (Ko, 2014), the Academic Self-Regulation Questionnaire (Ryan & Connell, 1989) revised by Kim (2002), and the Scale of Kang (2003), respectively. The collected data was analyzed using SPSS 26.0 and a Process Macro Model 2 (multiple additional modulation effect). The results of the study are summarized as follows. First, middle school students' internal control, autonomous motivation, and perceived parental pressure on academic performance directly affected the students's academic procrastination. Second, the moderating role of parental pressure on academic performance was significant. On the other hand, the moderating role of autonomous motivation was not significant. In conclusion, the results of this study suggest that in order to reduce and prevent academic procrastination it is important to improve internal control by helping middle school students become confident enough to believe that they have the ability to change their behavior and achieve their aims. At the same time, parents need to be interested in the process rather than only the academic performance of their children and support their autonomy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1110-1115
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• 2004

Water covers two-thirds of the earth and has a great influence on the future existence of all human being. Thailand has extensive coastline and near shore water that contain vast biological and mineralogical resources. The rivers and canals can be found around the country especially in the Bangkok, which once called the Venice of the East. Autonomous underwater robot (AUR) will be soon a tool to help us better understand water resources and other environmental issues. This paper presents the design and basic control of a six-degree of freedom AUR "Chalawan", which was constructed to be used as a testbed for shallow. It is a simple low cost open-frame design, which can be modified easily to supports various research areas in the underwater environment. It was tested with a conventional proportional-integral-derivative (PID) controller. After fine-tuning of the controller gains, the results showed the controller's good performances. In the future, the dynamic model of the robot will be analyzed and identified. The advanced control algorithm will be implemented based on the obtained model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1008-1013
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• 2005

In this paper, position tracking control of an autonomous helicopter is presented. Velocity is controlled by using an optimal state controller LQR. A position control loop is added to form a PD controller. To minimize a position tracking error, neural network is introduced. The reference compensation technique as a neural network control structure is used, and a position tracking error of an autonomous helicopter is compensated by neural network installed in the remotely located ground station. Considering time delays between an autonomous helicopter and the ground station, simulation studies have been conducted. Simulation results show that the LQR with neural network compensation performs better than that of the LQR itself.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.335-335
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• 2000

Applications such as unmanned aerial vehicles (UAVs), autonomous underwater vehicles (AUVs) and the time varying nature of their navigation, guidance and control systems motivate an integrated approach to trajectory general ion and trajectory tracking for autonomous vehicles. In this paper, an experimental testbed was designed for studying this integrated trajectory control approach. In this paper we apply the separating approach to an autonomous nonlinear vehicle system. A new linear matrix inequality based H$_{\infty}$ control technique for periodic time-varying systems is applied to the role of trajectory tracking. Trajectory general ion is accomplished by exploit ing the differential flatness property of the vehicle system; this at lows product ion of desired feasible nominal or reference trajectories from certain ″flat'system outputs. Simulation and experimental results are presented showing stable tracking of a periodic circular trajectory.

• International Journal of Control, Automation, and Systems
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• 제4권4호
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• pp.395-404
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• 2006

The objective of this paper is to generate a desired flight path to be followed by an autonomous airship. The space is supposed without obstacles. As there are six degrees of freedom and only three inputs for the LSC AS200 airship, three equality constraints appear due to the under-actuation.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제9권6호
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• pp.674-682
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• 2003

선박 자율운항시스템(autonomous navigation system)이란 선박운항에 있어 항해계획을 수립하고 현재의 선박운항 상태를 파악하여 주변 상황변화를 예측하고 대처하는 항해 전문가의 능력을 전산화한 것이다. 선박 자율운항시스템은 항해, 충돌회피, 선체유지, 자료융합, 운동제어 그리고 이를 통합하는 아키텍처로 구성되어 있다. 운동제어시스템은 선박의 유체학적 특성을 고려하여 해도 상에 원하는 위치로 선박을 이동하기 위해서 추진 및 조타장치를 제어하는 시스템으로 자율운항제어시스템에 필수적인 구성 시스템 중에 하나이다. 본 논문은 운영플랫폼인 가상세계시스템을 기반으로 운영되는 선박자율운항시스템과 운동제어시스템의 연동과 구현에 관한 연구이다. 운동제어시스템은 충돌회피시스템으로부터 상위 레벨의 고수준제어 요구치를 전달받아 조타 및 추진치로 변환하고 조타장치와 추진장치를 제어하는 시스템이다. 본 논문에서 선박 운동 특성을 수학적으로 모방하는 Oldenburger의 제어 이론에 기반하여 선박운동제어기를 개발하고 성능검정을 위해 선박시뮬레이터에서 다양한 시나리오를 바탕으로 시뮬레이션 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1113-1114
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• 1996

We describe an algorithm to control an autonomous guided vehicle with 2-diagonal driving wheels, which navigates in the clean room.

• 한국안전학회지
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• 제36권4호
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• pp.1-11
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• 2021

Piping systems comprising pumps and valves are essential in the power plant, oil, and defense industry. Their purpose includes a stable supply of the working fluid or ensuring the target system's safe operation. However, piping system accidents due to leakage of toxic substances, explosions, and natural disasters are prevalent In addition, with the limited maintenance personnel, it becomes difficult to detect, isolate, and reconfigure the damage of the piping system and recover the unaffected area. An autonomous recovery piping system can play a vital role under such circumstances. The autonomous recovery algorithms for the piping system can be divided into low-pressure control algorithms, hydraulic resistance control algorithms, and flow inventory control algorithms. All three methods include autonomous opening/closing logic to isolate damaged areas and recovery the unaffected area of piping systems. However, because each algorithm has its strength and weakness, appropriate application considering the overall design, vital components, and operating conditions is crucial. In this regard, preliminary research on algorithm's working principle, its design procedures, and expected damage scenarios should be accomplished. This study examines the characteristics of algorithms, the design procedure, and working logic. Advantages and disadvantages are also analyzed through simulation results for a simplified piping system.