• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.35 no.5
• /
• pp.389-404
• /
• 2017

The main purpose of this presented investigation is to build up the BHMS based on GNSS. This proposed monitoring system can conduct the deflection and dynamic characteristics analysis by using only GNSS positioning solution. The general bridge monitoring system being operated recently is composed of a combination of various sensors that are able to conduct deflection monitoring and dynamic characteristics monitoring analysis at the same time. However, GNSS based BHMS has the unique procedure in terms of data analysis. In the other words, GNSS positioning solution is firstly applied to deflection monitoring analysis then, this deflection analysis can be sequentially reflected in the dynamic characteristics. Unfortunately, the adjustment result of GNSS positioning solution estimated through various options and conditions and the process of monitoring analysis has not been fulfilled systematically. This means that different results or analysis value are presented according to the methodology and officers. Most of researches have been focusing on deflection monitoring analysis and some investigation regarding to dynamic characteristics is recently introduced. Moreover, it is not still reported the systematic investigation with regards to proper filtering and analysis methodology. This study was carried out based on a large amount of data, from this, various variables not reported yet are actively considered. Therefore, specific software for both monitoring analysis have been developed.

• Journal of Ocean Engineering and Technology
• /
• v.10 no.3
• /
• pp.153-161
• /
• 1996

This paper presents a design method of dynamic positioning control system for floating platform with rotatable and retractable thruster using $H_{\infty}$ control technique. The norm band of uncertainty is captured by multiplicative perturbation between nominal model and reduced order model. A controller robust to the uncertainty is designed applying $H_{\infty}$ synthesis. The control law satisfying robust stabillity and nominal performance condition is determined through the mixed sensitivity approach. The evaluation for the resultant controller obtained by $H_{\infty}$ synthesis is done through simulations of the closed loop system. The results of $H_{\infty}$ synthesis are compared to those of the traditional LQ synthesis method.

• Journal of Advanced Research in Ocean Engineering
• /
• v.1 no.2
• /
• pp.94-105
• /
• 2015

In this study, a thruster allocation method of a deep-sea working vessel was proposed with the aims of producing the demanded generalized forces and moment for dynamic positioning while at the same time minimizing total power. For this, an optimization problem for thrust allocation was mathematically formulated with design variables, objective function, and constraints. The genetic algorithms (GA) was used to solve the formulated problem. The proposed method was applied to an example of finding optimal thrust allocation of the deep-sea working vessel having 5 thrusters. The result showed that the method could be used to determine better strategy for thruster allocation of the vessel as compared to existing study.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.1
• /
• pp.8-19
• /
• 2003

Special purpose vessels such as drillship and ocean research vessels install the DPS(Dynamic Positioning System) to maintain the position and heading for long-time operation. This paper deals with the design parameters for the control theory and filter algorithms of DP system. for the environmental loadings wind forces, current forces and wave forces were considered. In order to estimate the low frequency motions without first-order wave motion, the Kalman filter was used and it was assumed that the first-order wave forces correspond to system noises and first-order wave motions are measurement noises. In this simulation, the length of research vessel is 65 meters and it has four thrusters to maintain the position. The ability of keeping position and heading was confirmed. For the calculation of thruster input the LQR and LOI control theory were adopted and the effects of gain were investigated.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.10a
• /
• pp.28-30
• /
• 2014

Dynamic Positioning System(DPS)은 그 신뢰성 및 대체 시스템에 따라 IMO 및 각 선급에서 3개의 class(등급)로 나누고 있다. IMO MSC/Circ 645에 의하면 DPS는 Class 1, 2, 및 3로 나뉘어 있으며 등급이 높을수록 좀 더 신뢰성 있고 안전하게 DP 선박을 운용할 수 있다. 이러한 DPS의 등급은 DP 선박을 건조할 때 그 선박의 사용 목적 및 필요성 신뢰도에 따라 건조되고 있으나 최근에는 이미 건조되어 있는 DP 선박의 등급을 개조를 통해 변경하여 사용하기도 한다. 본 연구에서는 DP Class 1선박을 DP Class 2 선박으로 변경하기 위해서는 어떠한 IMO 및 선급 요건의 만족이 필요하며 이를 위해서 어떠한 설비의 추가가 필요한지를 알아보고 이를 실제 사례를 통해 확인 및 검증해 본다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.285-290
• /
• 2006

This paper presents an adaptive neural network based controller and its application to Dynamic Positioning (DP) control system of ship. The proposed neural network based controller is developed for station-keeping and low-speed maneuvering control of ship. At first, the DP system configuration is described. And then, to validate the proposed DP system, computer simulations of station-keeping and low-speed maneuvering performance of a multi-purpose supply ship are presented under the influence of measurement noise, external disturbances such as sea current, wave, and wind. The simulations have shown the feasibility of the DP system in various maneuvering situations.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.18 no.4
• /
• pp.1122-1140
• /
• 2024

The importance of indoor positioning has grown in numerous application areas such as emergency response, logistics, and industrial automation. In ships, indoor positioning is also needed to provide services to passengers on board. Due to the complex structure and dynamic nature of ship environments, conventional positioning techniques have limitations in providing accurate positions. Compared to other indoor positioning technologies, Bluetooth 5.1-based indoor positioning technology is highly suitable for ship environments. Bluetooth 5.1 attains centimeter-level positioning accuracy by collecting In-phase and Quadrature (IQ) samples from wireless signals. However, distorted IQ samples can lead to significant errors in the final estimated position. Therefore, we propose an indoor positioning method for ships that utilizes a Deep Neural Network (DNN) combined with IQ fingerprint maps to overcome the challenges associated with accurate location detection within the ship. The results indicate that the accuracy of our proposed method can reach up to 97.76%.

• Journal of Power System Engineering
• /
• v.16 no.2
• /
• pp.66-74
• /
• 2012

In this paper, the authors propose a new approach to control a barge type surface vessel. It is based on the Dynamic Positioning System(DPS) design. The main role of barge ship is to carry and supply the materials to the floating units and other places. To carry out this job, it should be positioned in the specified area. However sometimes the thrust systems are installed on it, and in general the rope control by mooring winch system is used. It may be difficult to compare the control performances of two types. If we consider this problem in point of usefulness, we can easily find out that the winch control system is more useful and applicable to the real field than the thrust control system except a special use. Therefore, in this paper we consider a DPS design problem which can be extended to the many application fields. The goal of this paper is twofold. First, the sliding mode controller (SMC) for positioning the our vessel is proposed. Especially, in this paper, a robust stability condition is given based on descriptor system representation. In the result, the sliding mode control law guarantees to keep the vessel in the defined area in the presence of environmental disturbances. And second, the thrust allocation problem is solved by using redistributed pseudo-inverse (RPI) algorithm to determine the thrust force and direction of each individual actuator. The proposed approach has been simulated with a supply vessel model and found work well.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.1
• /
• pp.343-364
• /
• 2021

In the 5G era, the communication networks tend to be ultra-densified, which will improve the accuracy of indoor positioning and further improve the quality of positioning service. In this study, we propose an indoor three-dimensional (3D) dynamic reconstruction fingerprint matching algorithm (DSR-FP) in a 5G ultra-dense network. The first step of the algorithm is to construct a local fingerprint matrix having low-rank characteristics using partial fingerprint data, and then reconstruct the local matrix as a complete fingerprint library using the FPCA reconstruction algorithm. In the second step of the algorithm, a dynamic base station matching strategy is used to screen out the best quality service base stations and multiple sub-optimal service base stations. Then, the fingerprints of the other base station numbers are eliminated from the fingerprint database to simplify the fingerprint database. Finally, the 3D estimated coordinates of the point to be located are obtained through the K-nearest neighbor matching algorithm. The analysis of the simulation results demonstrates that the average relative error between the reconstructed fingerprint database by the DSR-FP algorithm and the original fingerprint database is 1.21%, indicating that the accuracy of the reconstruction fingerprint database is high, and the influence of the location error can be ignored. The positioning error of the DSR-FP algorithm is less than 0.31 m. Furthermore, at the same signal-to-noise ratio, the positioning error of the DSR-FP algorithm is lesser than that of the traditional fingerprint matching algorithm, while its positioning accuracy is higher.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.348-352
• /
• 2002

a basis such as IT(Information Technology), NT(Nano Technology) and BT(Bio Technology). Recently, NT is applied to various fields that are composed of science, industry, media and semiconductor-micro technology. It has need of IT that is ultra-precision positioning technology with strokes of many hundreds mm and maintenance of nm precision in fields of ultra micro process, ultra precision measurement, photo communication part and photo magnetic memory. This thesis represents optimal design on ultra-precision positioning with single plane X-Y stage and development of artificial control system for adequacy of industrial demand. Also, dynamic simulation on global stage is performed by using ADAMS (Automated Dynamic Analysis of Mechanical System) for the purpose of grasping dynamic characteristic on user designed X-Y global stage. The error between displacements from micro stage and from FEM(Finite Element Method) is 3.53% by verifications of stability on micro stage and control performance. As maximum Von-mises stress on hinge of micro stage is 5.981kg/mm$^2$ that is 1.5% of yield stress, stability on hinge is secured. Preparing previous results, optimal design of micro stage can be possible, and reliance of results with FEM can be secured.