• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.1
• /
• pp.32-44
• /
• 2015

In general, a series of ship steering motion is represented by the combination of translational motion and rotational motion of the ship. Especially, special-functioned ships such as large-scale cruises, ships for installing underwater optical cable, and diver ships must be able to reveal only a translational motion without the change of orientation. In this paper, a method to comprise an integrated control system based on the joystick as a command instrument for translational motion control is suggested. In order to realize the translational motion control system, several algorithms are suggested including the velocity command generation, the selection of motional variables, and the generation and tracking of reference inputs for the selected motional variables. A simulation bench is composed to execute simulations for several translational motion commands. At last, the effectiveness of the proposed method is verified by analyzing the simulation results.

• Journal of Navigation and Port Research
• /
• v.46 no.6
• /
• pp.554-561
• /
• 2022

Technology development related to maritime autonomous surface ships (MASS) is actively progressing around the world. However, since there are still many technically unresolved problems such as communication, cybersecurity, and emergency response capabilities, it is expected that it will take a lot of time for MASS to be commercialized. In this study, we proposed a ship group navigation system in which one leader ship and several follower ship are grouped into one group. In this system, when the leader ship begins to navigate, the follower ship autonomously follows the path of the leader ship. For path following, PD (proportional-derivative) control is applied. In addition, each ship navigates in a straight line shape while maintaining a safe distance to prevent collisions. Speed control was implemented to maintain a safe distance between ships. Simulations were performed to verify the ship group navigation system. The ship used in the simulation is the L-7 model of KVLCC2, which has related data disclosed. And the MMG (Maneuvering Modeling Group) standard method proposed by the Japan Society of Naval Architects and Ocean Engineering (JASNAOE) was used as a model of ship maneuvering motion. As a result of the simulation, the leader ship navigated along a predetermined route, and the follower ship navigated along the leader ship's path. During the simulation, it was found that the three ships maintained a straight line shape and a safe distance between them. The ship group navigation system is expected to be used as a navigation system to solve the problems of MASS.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.04a
• /
• pp.182-183
• /
• 2009

• Nuclear industry
• /
• v.8 no.9 s.67
• /
• pp.17-27
• /
• 1988

최근 일본의 원자력 비판운동은 이방원전의 부하추종운전시험 반대를 계기로 새로운 전개를 보이고 있는데, 이 반대움직임은 선동적인 내용으로 원자력발전에 대한 반대감정을 자극한 광뢰 륭씨 저 ${\ulcorner}$위험한 이야기${\lrcorner}$에 의해서 시작되었다고 할 수 있다. 그러나 이 책의 내용에는 과학적인 지식을 잘못 인식한 주장과 신문기사 및 논문의 인용에 모순과 의문이 많으며, 또한 불확실한 정보에 근거를 둔 내용도 많다. 따라서 일본원자력문화진흥재단에서는 이러한 부분을 분석정리하여 ${\ulcorner}'$위험한 이야기'의 오인${\lrcorner}$이란 자료를 발간하였다. 다음은 이 자료를 요약한 것이다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.4
• /
• pp.166-175
• /
• 2001

The high speed tracking control of a 6-6 Stewart platform manipulator (SPM) normally requires knowledge of its complex full dynamics and measurement of its base motion when the SPM operates on a motion nit. In this study, an enhanced sliding mode control scheme has been developed, which is based on the reduced dynamics, not necessitating measurement of the base motion. The enhanced sliding mode control implemented with the perturbation compensation and modified reaching phase alleviation functions has been successfully employed for high speed tacking control of the laboratory SPM, when it is subjected to a virtual base motion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.10a
• /
• pp.99-100
• /
• 2016

드론이나 이동형 촬영장비에 장착된 카메라로부터 깨끗하고 안정된 영상을 획득하기 위해서는 짐벌시스템의 안정화기 설계가 필요하다. 짐벌시스템은 카메라 모듈을 지지하는 구조와 외부로 부터의 진동을 차단하면서 정확한 각도를 추종하는 안정화기로 구성된다. 이동형 촬영장비나, 비행중인 드론에는 매우 다양한 주파수 성분의 진동이 발생되는데, 이러한 진동을 제어하기 위하여 6자유도 운동방정식을 유도하고, 이 중에서 본 논문에서는 일반적으로 rolling, pitching, yawing 운동에 대해서는 PID 제어기를 사용하여 안정화를 제어하기만, 카메라종류나 짐벌시스템 구조가 바뀔 때 마다 PID 파라미터를 변경해야 되는 경우가 빈번하다. 본 논문에서는 이런 문제점을 개선하기 새로이 제기된 제어 기법인 지적 PID(intelligent PID) 제어를 통하여 진동제어를 수행하여 짐벌시스템의 안정화를 위한 제어기법을 제안하고자 한다.

• Proceedings of the KIPE Conference
• /
• 2018.11a
• /
• pp.18-20
• /
• 2018

본 논문에서는 위치-속도 모드전환 제어기를 제안하고 이 제어기를 활용한 운동범위 제약을 가진 기계의 연착륙 방법을 제시한다. EGR 밸브와 같은 기계제품들은 이동할 수 있는 범위를 가지며 범위 내에서 위치를 제어한다. 위치제어 중 양끝 위치로 이동시 기계는 빠른 속도로 충돌할 수 있다. 속도가 빠르면 빠를수록 충돌 시, 충격력이 커지며, 충격력으로 기구물은 빠르게 마모되고 수명을 단축시킬 수 있다. 따라서 양끝 위치 이동 시, 일시적으로 속도를 제어할 수 있는 제어기가 필요하다. 제안된 위치-속도 모드전환제어기는 Hanus Scheme을 사용하여 모드전환 시, 범프효과로 인한 부작용을 감소시켰으며, 모드전환 이후 모드 전환된 제어기의 지령을 빠르게 추종한다. 마지막으로, EGR 밸브 양끝 위치 학습알고리즘에 적용시켜 시험하였다.

• Journal of IKEEE
• /
• v.3 no.2 s.5
• /
• pp.250-258
• /
• 1999

This paper presents a decentralized adaptive controller design for a Magnetically Levitated Fine Manipulator to follow the given trajectory as close as possible in spite of coupling effects between motion axes(degree of freedoms or subsystems). The present controller consists of two parts: the model reference controls based on known subsystems and the local adaptive controls. The former stabilizes the motion of the manipulator so as to follow that of the reference model. The latter reduces tracking errors due to coupling disturbances by adjusting the local gains to such levels that override interactions and assure the stability of the overall system. Through several experimental results, it has been shown that the decentralized adaptive control scheme has better tracking performances comparing to the PID controller case as well as good disturbance(coupling) rejection property.

• Journal of Advanced Navigation Technology
• /
• v.5 no.1
• /
• pp.19-25
• /
• 2001

In this study an analysis on flight characteristics and flight control methods for a wing in ground effect vehicle is made. In order to closely view its nonlinearity a few limit cycles are examined and related to the characteristics of the linearized systems. Several flight control methods are compared for the cruise mode with initial height error and command tracking mode of ascending, cruise, and descending. In comparison performance and the implementation aspects are examined. For the possible control inputs, combinations of elevator, thrust, and flap are considered and LQR-based output command tracking scheme is applied in the control system design.

• Journal of the Korea Society for Simulation
• /
• v.21 no.1
• /
• pp.35-43
• /
• 2012

In this study, underwater behaviors of negative buoyant body and positive buoyant body, which are ejected from a platform, are compared through eject test and simulation. CFD(Computational Fluid Dynamics) method is used to calculate the hydrodynamic derivatives of negative buoyant body with varied hull. Hydrodynamic derivatives that cannot be calculated with CFD are used with the same values of base shape. The pitch angles of test data are much bigger than those of simulated data, and the reason is supposed to be the trailing air effect. A more accurate simulation is possible via modified force modeling which reflects this phenomenon. The underwater behaviors of positive buoyant body and negative buoyant body are somewhat different with each other at the same eject condition, but it may not be a problem in the view of operation.