Jin Yicheng

Ship simulation using virtual reality technique

In this paper, ship is simulated and modeled applying the virtual reality technique. In addition, the ship model is verified with IMO resolution or the ship trial data. The ship mathematic model libraries are created and modified or tested by the IMO Ship Maneuverability resolution in order to meet the needs of ship handling simulator. Moreover, three dimensions viewing of ship is simulated using the virtual reality technique. The viewing effect is very living in the Large Ship Manouvring Simulator.

Real-time ocean wave in multi-channel marine simulator

We present an adaptive scheme for real-time simulating irregular long crest waves in multi-channel marine simulator. The method restricts computations to the visible part of the ocean surface in each view channel, adapts the geometric resolution to the viewing distance and only considers the visible waves wavelengths. The method allows the user to move over an unbounded ocean following the own-ship, and immersed in a real-time updated photo-realistic ocean environment.We present an adaptive scheme for real-time simulating irregular long crest waves in multi-channel marine simulator. The method restricts computations to the visible part of the ocean surface in each view channel, adapts the geometric resolution to the viewing distance and only considers the visible waves wavelengths. The method allows the user to move over an unbounded ocean following the own-ship, and immersed in a real-time updated photo-realistic ocean environment.

Real-time Shadow Rendering in Scene System of Marine Simulator

In the large-scale scene system based on scene management software, an efficient method was presented to render shadow with shadow volume algorithm. Approaches were discussed to convert scene model from openflight file to 3ds file. The data used to determine silhouette edge was obtained by accessing the simplest LOD of model A new method that reduced silhouette edge by removing redundant internal edge was provided. A new strategy of shadow rendering was presented: depending on models position, shadows were rendered with z-pass algorithm utilizing CPU or z-fail algorithm within vertex shader. The method and strategy presented in this paper can be integrated directly into the large-scale scene system based on scene management software. The effect of shadow rendering meets the real-time and reality requirements of scene system.

Multi-Level Virtual Reality System for Marine Education and Training

Full Mission Marine Simulator (FMMS) is a fully immersive Visual Reality (VR) System for marine education and training and is valuable and effective for fostering the qualified and competent seafarer. However, many problems, such as limited accessibility, high expenditure, and difficult maintenance etc, limit their pervasive use. Then we developed a partially immersive Desktop Marine Teaching System (DMTS) based FMMS which is low cost and easy to maintenance. Furthermore, one Web-based Marine Training Environment (WMTE) is proposed, which fully combining web technology, high fidelity simulation, and e-learning tools to create a more cost-effective and flexible training environment. In this paper, FMMS, DMTS and WMTE are combined together and supplemented each other to a multi-level VR system in the whole marine training process. Experimental results demonstrated that the multi-level VR system can provide a consistent and more effective medium for improving marine education and training.

A Prototype of Marine Search and Rescue Simulator

There are many of distress vessels in marine to wait for succor. Marine Search and Rescue (SAR) is an important social responsibility and it is very urgent to improve marine SAR ability by peacetime training. However, conventional real ship practical training on the sea is expensive and the training circumstance differs from of real SAR circumstance which is very adverse. This paper brings forward one prototype of Marine SAR simulator (MSARS) which is a very effective, flexible and low cost training method. The MSARS is constructed by reusing the existing shiphandling simulators and adding rescue helicopter simulation unit. Then, Global Maritime Distress Safety System (GMDSS) simulation is integrated into the MSARS. Distress vessel, rescue vessels, rescue helicopter are shared one highly realistic and reliably marine SAR virtual environment through visual and auditory display. It can provide all kinds of marine SAR environments and is effective for all kinds of marine SAR missions training. Further more, anti-pirate drilling also can be implemented in the MSARS.

Real-time rendering of ocean in marine simulator

The scientific, rapid and realistic rendering of ocean is always a difficult problem in marine simulator. A spectrum method of ocean simulation was developed in the paper. The fast Fourier transform based on GPU was used to generate the height map. A grid model of concentric circles was proposed to replace ocean surface geometry, and the height of grid vertex could be obtained through accessing the height map in vertex shader. Then the choppy waves was simulated and the repeating tiles of ocean was reduced. The reflection and refraction of ocean surface were rendered. The method developed in the paper has been successfully applied in the visual system of marine simulator.

Design radar signal interface for navigation Radar/ARPA simulator using radar display

Using radar/ARPA simulators for seafarers training is made mandatory by International Maritime Organization (lMO) as early as 1978. This paper presents a new radar simulator using one PC, one radar signal interface and one radar display. PC generates radar echo of any sea area and simulates all kinds of radar echo effects and features. Then the radar signal interface receives the radar echo through PC USB and outputs all kinds of signals to radar display. In the interface, lots of logical circuit is implemented by CPLD, which largely simplifies the design and improves the flexibility. Seafarers can operate the radar display in simulated environment of any sea area in Radar/ARPA Operation training. It provides more flexibility and fidelity and effectively improves the training effect. The result shows that this type of radar simulator meets with the requirements of radar simulator standard completely and has been used in our full mission ship handling simulator successfully.

Ship motion modeling and simulation in Ship Handling Simulator

For developed irregular waves, wave heights or wave amplitudes are gained using the wave spectrums. Based on the hypothesis of Froude-Krylov, ship shape is predigested box. Wave forces and moments to ship motion can be calculated. They are added in the motion mathematical models, and ship six degrees of freedom mathematical models are given. Using the fourth order Runge - Kutta integration method solves differential equations. The mathematical models are applied to Full Mission Ship Handling Simulator. Six degrees of freedom of the ship: the location, attitude and speed and acceleration are passed to the other modules in the navigation simulator, in order to achieve interaction between human and computer. As an example, a cargo ship that its displacement is ten thousand tons are simulated in three sea states, the time histories of motion are good and the viewing scene is very vivid. The results are shown that the mathematical models can meet the engineering demands.

The Marine Safety Simulation based Electronic Chart Display and Information System

Navigation safety has a huge impact on the world economy and our everyday lives. One navigation safety simulation model in ECDIS based on international standard format (S-57) is put forward, which is mainly involved in route plan and route monitoring. The universal kriging interpolation is used in the route planning and to compute the water depth of any place in the sea bottom. The man-machine conversation method is taken to amend planned route to obtain autodeciding of feasibility according to ECDIS information, and the route monitoring algorithm is improved by enhancing its precision caused by screen coordinate conversion. The DCQA (distance close quarters situation of approach) model and TCQA (time close quarters situation of approach) model are adopted to judge if the close quarters situation or the risk of collision between own ship and target ship is emerging. All these methods are proven to be reliable through the navigation simulator made by Dalian Maritime University which is certified by DNV to class A.

Ship Virtual Mass and Virtual Rotation Moment of Inertia Estimation Based on Model Tank Data

It is important to gain the ship hydrodynamic coefficients in the process of ship motion modeling and simulation. Currently, hydrodynamic coefficients are available by tank test methods, theoretical calculations and the approximate estimation methods that based on the experimental data in the tank. In this paper, based on the ship test data in the tank, longitudinal and transverse virtual mass and virtual rotation moment of inertial can be estimated by multiple linear regressions. It is estimated with the existing formula of reference to compare. This formula can meet the precising engineering applications. It is well used as guide in ship motion modeling and it is applied to the general mathematical model of Ship Handling Simulator.