• Defense and Technology
• /
• 8호통권294호
• /
• pp.64-71
• /
• 2003

Rooivalk에 채택된 항전장착물은 프랑스의 Sextant가 주 개발자이며 3개의 다기능 디스플레이를 갖는 NVG 호환 G-Cockpit도 포함된다. Thales는 Topowl HMSD도 공급하는데 이것은 Denel사 Cumulus 공장에서 개발된 센서 터렛과 Pilkington Optronics와 공동개발한 Noctua PNVS와 연계된다. Rooivalk의 TDATS는 Topowl과 함께 작동하는 Cumulus사 Argos-780 EO 센서 터렛을 사용하고 있고 열상장비, TV카메라, 레이저 거리측정기, 레이저 표식기 그리고 자동추적기로 구성되어 있다.

• The Journal of the Korea institute of electronic communication sciences
• /
• 제16권1호
• /
• pp.37-44
• /
• 2021

This study is implemented as a sensor-less position controller capable of multi-turn detection to replace the expensive absolute encoder used in the turret servo system. For sensor-less control, the position information of the rotor is essential. For this, a magnetic flux estimator was implemented from the mathematical model of IPMSM used in the turret servo system. The position of the rotor and the angular velocity of the rotor were obtained using the rotor magnetic flux calculated from the magnetic flux estimator. Using the zero-crossing technique, one pulse was generated for each rotation of the estimated rotor magnetic flux to measure the number of multi-turns. Simulation and experiment results confirmed the usefulness of the proposed method.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 한국공작기계학회 2002년도 추계학술대회 논문집
• /
• pp.153-157
• /
• 2002

본 연구에서는 선반가공에서 일반적인 선반작업 후 밀링이나 드릴링 가공이 가능한 복합가공기의 역할을 한번에 수행할 수 있는 CNC 공구터렛의 홀더 주축에 대한 수학적 모델링을 통하여 시스템의 횡진동 및 비틀림 진동 해석으로 발생할 수 있는 진동 문제에 대처할 수 있는 방안을 제시 하고자 한다.

• Journal of the Society of Naval Architects of Korea
• /
• 제40권1호
• /
• pp.20-27
• /
• 2003

The FPSO is moored by mooring lines to keep the position of it. The nonlinear motion analysis of the moored FPSO must be carried out in the initial design stage because sea environments affect motion of it. In this paper, the mathematical model is based on the slow motion maneuvering equations in the horizontal plane considering wave, current and wind forces. The direct integration method is employed to estimate wave loads. The current forces are calculated by using mathematical model of MMG. The turret mooring forces are quasi-statically evaluated by using the catenary equation. The coefficients of a model for wind forces are calculated from Isherwood's experimental data and the variation of wind speed is estimated by wind spectrum according to the guidelines of API-RP2A. The nonlinear motions of FPSO are simulated under external forces due to wave, current, wind including mooring forces in time domain.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.847-848
• /
• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2013년도 춘계학술대회 논문집
• /
• pp.271-272
• /
• 2013

• Journal of the Society of Naval Architects of Korea
• /
• 제53권5호
• /
• pp.435-446
• /
• 2016

In this study, hydrodynamic and mooring analysis for LNG FSRU moored by an internal turret with 9 mooring lines are numerically performed using commercial softwares, Hydrostar and Ariane. Met-ocean combinations for screening method are taken from wave governed condition(BV Rule Note NR 493) with relative heading between wave and wind between −45° and +45° and relative heading between wind and current between −30° and +30°. Extreme mooring analysis and sensitivity analysis are performed for intact and damaged (=one line missing) conditions and the parameters for sensitivity analysis are wave peak period, peak enhancement factor and line pretension. In the viewpoint of the design tension in mooring line, chain diameter is designed to satisfy safety factor for each conditions. As the chain diameter is increased from 152mm to 171mm, the designtension is reduced while the minimum breaking load is increased.

• Journal of the Society of Naval Architects of Korea
• /
• 제50권1호
• /
• pp.8-13
• /
• 2013

Excessive yaw motion of a turret moored vessel was examined in this paper. The vessel was moored by an internal turret and catenary mooring lines. The experiments were conducted in regular waves. Turret moored vessel can oscillate from side to side or move to one particular direction, and eventually exhibit large yaw motion. The results showed that the excessive yaw occured for specific condition, ratio of wave lengths and vessel length. It was found that turret moored floating vessel was unstable for regular wave period from 14 to 18 sec and excessive yaw occurred to maximum 50 deg. The time series, trajectory, phase plot and qualitative analysis are performed. The analysis showed that the results of experiments agreed with the that of analytic method and the excessive yaw could be predicted by the stability analysis.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 한국해양공학회 2002년도 추계학술대회 논문집
• /
• pp.161-166
• /
• 2002

As offshore oil fields move towards the deep ocean, the oil production systems such as FPSO are being built these days. Generally, the FPSO is moored by turret mooring lines to keep the position of FPSO. Thus nonlinear motion analysis of moored FPSO must be carried out in the initial design stage because sea environments affect motion of it. In this paper the mathematical model is based on the slow motion maneuvering equations in the horizontal plane considering wave, current and wind forces. The direct integration method is employed to estimate wave loads. The current forces are calculated by using mathematical model of MMG. The turret mooring forces are quasi-statically evaluated by using the catenary equation. The coefficients of a model for wind forces are calculated from Isherwood's experimental data and the variation of wind speed is estimated by wind spectrum according to the guidelines of API-RP2A. The nonlinear motions of FPSO are simulated under external forces due to wave, current, wind including mooring forces in time domain.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 1989년도 하계종합학술대회 논문집
• /
• pp.66-69
• /
• 1989

In this paper, the LQG/LTR design method is applied of the third order linear time invariant plant model which is the SISO turret-gun servo-mechanism. The dynamic characteristics and the performance of the LQG/LTR controller are analyzed by the computer simulation, and compared with those of PID controller which has been already applied to the turret servomechanism under the sane design specifications.